EExperime

Poipu, K

Second

ental La

Kauai, Haw

Worksh

aboratory

waii, Februa

op on

y Astrop

ary 23-26,

physics

2015

The second workshop will take place at the Sheraton Kauai Resort in Poipu, Kauai, Hawaii, starting with a reception and registration on February 22, 2015, at 6 pm. Based on the success and enthusiasm of the first workshop in 2013, the workshop again features invited (senior and junior researchers) as well as contributed talks and poster presentations focusing on the interaction of ionizing radiation (UV, VUV, gamma rays, charged particles) and neutrals (atoms, radicals, molecules, grains) with low temperature solids (ices, minerals, organics). Presentations have been extended to include observations, modeling, and electronic structure calculations that can directly link to laboratory experiments.

During the last decade, significant new experimental techniques have been developed to investigate the interaction of ionizing radiation (UV, VUV, gamma rays, charged particles) and of neutrals (atoms, radicals, molecules, grains) with surfaces of solids (ices, minerals, carbonaceous compounds) in the Solar System and in the Interstellar Medium (ISM). These processes provide new fundamental insights into the processes that are critical to the chemistry in the ISM, star and planet forming regions, and on/in icy objects in the Solar System ranging from the formation of the simplest molecule (molecular hydrogen) to astrobiologically important species such as amino acids and sugars. Considering the highly anticipated results from space craft missions such as New Horizons and Rossetta, there is an increasing necessity for the dissemination of laboratory results. As such we are grateful that so many of you have utilized this opportunity to present your work to the community and hope that this level of enthusiasm will continue to provide a solid foundation for future workshops to come.

We are looking forward to seeing you on Kauai in 2015.

Sincerely,

The Organizers

Brant Jones, University of Hawaii at Manoa

Murthy Gudipati, JPL

Mark Loeffler, NASA Goddard

Gianfranco Vidali, Syracuse University

Helen Fraser, Open University, UK

Ralf I. Kaiser, University of Hawaii at Manoa

Naoki Watanabe, University of Hokkaido, Japan

Time Monday Tuesday Wednesday Thursday Session Chair Brant Jones Gianfranco Vidali Karin Öberg Ralf Kaiser

8:00 – 8:40

Louis le Sergeant

d’Hendecourt

(8:20 – 9:00)

Murthy Gudipati Gianfranco Vidali

Helen Fraser

8:40 – 9:20 Pierre de Marcellus

(9:00 – 9:20) Lucy Ziurys Jean Louis Lemaire

Guillermo

Manuel Muñoz

Caro

9:20 – 10:00 Laurent Nahon Pascale

Ehrenfreund David Anderson

Jean-Hugues

Fillion

10:00 – 10:20 Break with snacks

Session Chair Murthy Gudipati Steven Sibener Reggie Hudson Patrice Theulé

10:20 – 11:00

Adwin Boogert Reggie Hudson Yu-Jung Chen Lahouari Krim

11:00 – 11:25

Ralf Kaiser

Lisseth Gavilan Brett McGuire Marko Förstel

11:25 – 12:05 Sergio Ioppolo Naoki Watanabe Thomas Henning

Katherine Tran

12:05 – 12:25

Paul Brumer

Yuki Kimura Andrew Turner Brant Jones

12:25 – 1:05

Steven Sibener

Karin Öberg Jean-Baptiste Bossa Albert Rimola

1:05 – 6:00 Free Time

End of

Conference

Session Chair Naoki Watanabe Dag Hanstorp Thomas Orlando

6:00 – 6:40

Bing-Ming Cheng

Thomas Orlando Emmanuel Dartois

6:40 – 7:05 Matthew Abplanalp Marie-Aline

Martin-Drumel Sven Thorwirth

7:05 – 7:45

Musahid Ahmed

Yuan-Pern Lee Liv Hornekær

7:45 – 8:05

Niels Ligterink

Martina D’Angelo Daniel

Paardekooper

8:05 – 8:25 Break with snacks

Session Chair Wolf Geppert Sergio Ioppolo

8:25 – 9:05

Poster Session

Léon Sanche

Dag Hanstorp

9:05 – 9:25

Robert Continetti

Thushara Perera

9:25 – 10:05

Patrice Theulé

Wolf Geppert

WHY INTERSTELLAR ICES CAN BE CONSIDERED AS PRECURSORS FOR PREBIOTIC CHEMISTTRY?

Louis le Sergeant d’hendecourt,ab

aUniv. Paris-Sud, Institut d’Astrophysique Spatiale, « Astrochimie et Origines », UMR 8617, F-91405 Orsay, France; eCNRS, France

ldh@ias.u-psud.fr

ABSTRACT Interstellar ices made of quite simple and basic molecules (H2O, CO, CO2, CH3OH, NH3, CH4, etc.) are, by far, the most abundant molecular species in the universe (if one excepts H2), observed in molecular clouds where protostellar objects are detected. Since the constitutive elements (H, O, C, N, S (and P?)) are the most cosmically abundant, available and condensable, they are prone to favour the making of ices on solid grains. In the bulk mantles formed around silicates (or carbon) cores, a rich organic chemistry can develop and, thanks to the protective nature of the grains against destruction processes and because of their extremely high density (that of a solid namely), this organic chemistry leads to a very high chemical organic complexity. Radical chemistry generated by photo/thermos-chemical processes on these surfaces, may well leave to the formation of solid organic residues similar to those that routinely produced in the laboratory with ice templates and studied much further, using methods that are unusual in the astrophysical/chemical community but pertain to cosmochemistry (meteorites) and analytical chemistry. The organic material formed in these processes may resemble the Soluble Organic Matter observed in pristine meteorite. From numerous amino acids [1] aldehydes and sugars [2] detected in these residues to chiral molecules and enantiomeric excesses produced by ultraviolet Circularly Polarized Light from synchrotron radiation [3], one might seriously ask whether the chemistry of molecular clouds out of which stars, planetary systems and debris (comets, asteroids, dust) form, may not be seriously considered as the precursor of prebiotic chemistry that will take place in a given environment at the surface of a telluric planet as it may have been the case for the Earth. I will present the general frame of these experiments in relation with the possibly feeding of the necessary prebiotic chemistry at the origin of life. Certainly, prebiotic chemistry is very different in itself than astrochemistry but the starting bricks issued from astrochemistry may well be necessary for the possibility of developing life on planets under certain assumptions I will briefly discuss. REFERENCES [1] Meinert, C., Filippi, J.-J., de Marcellus, P., Le Sergeant d’Hendecourt, L. and Meierhenrich, U.J., ChemPlusChem, 77, 186-191 (2012). [2] de Marcellus, P., Meinert, C., Myrgorodska, I., Nahon, L., Buhse, T., Le Sergeant d’Hendecourt, L., Meierhenrich, U.J., PNAS, January 12th, 2015 [3] Modica, P., Meinert, C. de Marcellus, Nahon, L., Meierhenrich, U.J., Le Sergeant d’Hendecourt, L. Astrophys.J, 788, 79

THE IMPORTANCE OF PRE-COMETARY ICES IN ASTROCHEMICAL AND

PREBIOTIC EVOLUTION

Pierre de Marcellusa, Cornelia Meinert

b,e, Iuliia Myrgorodska

b,c, Laurent Nahon

c, Thomas

Buhsed, Louis Le Sergeant d’Hendecourt

a,e, and Uwe J. Meierhenrich

b

aUniv. Paris-Sud, Institut d’Astrophysique Spatiale, UMR 8617, F-91405 Orsay, France;

bUniv.

Nice Sophia Antipolis, Institut de Chimie de Nice, UMR 7272 CNRS, F-06108 Nice, France; cSynchrotron SOLEIL, F-91192 Gif-sur-Yvette, France;

dCentro de Investigaciones Químicas,

Universidad Autónoma del Estado de Morelos, Avenida Universidad 1001, 62209 Cuernavaca,

Mexico; eCNRS, France

pierre.demarcellus@ias.u-psud.fr

ABSTRACT

Interstellar ices (H2O, CO, CO2, CH3OH, NH3, CH4, etc.) are widely observed in the mid-

infrared range around protostellar objects [1], from which planets, comets and asteroids may

ultimately form. In the laboratory, experiments simulating the energetic (UV photons, cosmic

rays) and thermal evolution of ice analogues lead, after warming the sample up to room

temperature, to the formation of a water-soluble semi-refractory organic residue. Theses residues

have been studied thanks to numerous analytical techniques over the last thirty years, allowing

their partial physical and chemical characterisation [2] and showing that they contain a wide

variety of organic molecules, some of them of potential prebiotic interest, such as amino and di-

amino acids [3]. They can then be considered as analogues of pre-cometary and/or meteoritic

organic matter, in particular the soluble part (SOM).

I will present our last analyses in which we have detected aldehydes and sugars for the first time

in such laboratory residues [4]. I will discuss the potential implication of these results for

prebiotic chemistry, within an astrophysical scenario that emphasizes the central role of

extraterrestrial ice photo/thermo-chemistry as an ubiquitous phenomenon in protostellar media

and protoplanetary disks environments.

REFERENCES

[1] Öberg, K.I., Boogert, A.C.A., Pontoppidan, K.M. et al., The Astrophysical Journal, 740, 109-

124 (2011).

[2] Danger, G., Orthous-Daunay, F.-R., de Marcellus, P. et al., Geochimica et Cosmochimica

Acta, 118, 184–201 (2013).

[3] Meinert, C., Filippi, J.-J., de Marcellus, P., Le Sergeant d’Hendecourt, L. and Meierhenrich,

U.J., ChemPlusChem, 77, 186-191 (2012).

[4] de Marcellus, P., Meinert, C., Myrgorodska, I., Nahon, L., Buhse, T., Le Sergeant

d’Hendecourt, L., Meierhenrich, U.J., PNAS, submitted.

ASTROPHYSICAL SCENARI FOR THE ORIGIN OF BIOMOLECULAR ASYMMETRY PROBED BY CIRCULARLY-POLARIZED VUV SYNCHROTRON RADIATION

Laurent Nahon

Synchrotron SOLEIL laurent.nahon@synchrotron-soleil.fr

Synchrotron radiation appears to be a very valuable tool for laboratory astrophysics able to simulate the VUV spectrum of light (including Lyman-α) encountered in the ISM and planetary ionospheres. This is especially the case of the DESIRS beamline [1] at SOLEIL providing an intense, tunable, high resolution, VUV radiation with controlled polarizations, including Circularly Polarized Light (CPL). This last characteristics allows the study of several asymmetric photon-induced processes which could be part of an abiotic astrophysical scenario linked to the origin of life’s homochirality, the fact for instance that only L-amino acids are found in the biosphere. Assuming an extra-terrestrial formation of building blocks of life such as amino-acids, a possible abiotic explanation for the selection of the L enantiomers could be the exposure to CPL as an asymmetric bias during their journey towards Earth, inducing some enantiomeric excess (e.e) than could then be amplified on Earth. After an introduction to the laboratory astrophysics opportunities opened by VUV synchrotron radiation, asymmetric photon-induced processes leading to noticeable ee will be described: (i) The photon wavelength-controlled enantio-selective photolysis of racemic solid-films on the alanine amino acid leading to e.e. of up to 4 %,[2] as measured by 2D-GCMS techniques, in direct connection with anisotropy spectra recorded on similar samples.[3] (ii) Photochirogenesis on CPL-irradiated interstellar achiral ice analogs (H2O, NH3, CH3OH) leading to the asymmetric production of several amino acids with e.e up to 2.5 % for alanine, and with the same e.e sign for all amino acids at given wavelength. These excesses reverse sign by swapping the light helicity, showing a chirality transfer from photon to matter.[4] (iii) Photoelectron Circular Dichroism on gas phase alanine,[5] an asymmetric photoemission process observed as an intense asymmetry of the ejected electrons and therefore of the corresponding amino-acid recoiling ion, leading in a given light of sight to an e.e of up to 4 % at the Lyman α wavelength.[6]

[1] L. Nahon, N. de Oliveira, G. Garcia, J. F. Gil, B. Pilette, O. Marcouille, B. Lagarde, and F.

Polack, J. Synchrotron Rad. 19, 508 (2012). [2] C. Meinert, S. V. Hoffmann, P. Cassam-Chenaï, A. C. Evans, C. Giri, L. Nahon, and U. J.

Meierhenrich, Angew. Chem.-Int. Edit. 53, 210 (2014). [3] C. Meinert, J. H. Bredehoeft, J. J. Filippi, Y. Baraud, L. Nahon, F. Wien, N. C. Jones, S. V.

Hoffmann, and U. J. Meierhenrich, Angew. Chem.-Int. Edit. 51, 4484 (2012). [4] P. Modica, C. Meinert, P. de Marcellus, L. Nahon, U. J. Meierhenrich, and L. L. S. d'Hendecourt,

The Astrophysical Journal 788, 79 (2014). [5] M. Tia, B. Cunha de Miranda, S. Daly, F. Gaie-Levrel, G. A. Garcia, L. Nahon, and I. Powis, J.

Phys. Chem. A 118, 2765 (2014). [6] M. Tia, B. Cunha de Miranda, S. Daly, F. Gaie-Levrel, G. Garcia, I. Powis, and L. Nahon, J.

Phys. Chem. Lett. 4, 2698 (2013).

THE COMPOSITION OF INTERSTELLAR ICES

Adwin BoogertUniversities Space Research Association, Stratospheric Observatory for Infrared

Astronomy, NASA Ames Research Center, MS 232-11, Moffett Field, CA 94035, USAacaboogert@alumni.caltech.edu

ABSTRACT

Infrared spectroscopy of dense clouds and young stars has led to the secure identification of justa handful of species embedded in the ice mantles on refractory grains (Boogert, Gerakines, &Whittet, 2015): H2O, CO, 13CO, CO2, 13CO2, CH3OH, NH3, and CH4. All other proposed icespecies are less securely identified on the basis of a single absorption feature, which for some iswell fitted (peak position and shape) by laboratory spectra (H2CO, OCN-, OCS), but not forothers (e.g., HCOOH, NH4

+). Conversely, the origin of a number of interstellar ice absorptionfeatures is highly uncertain. Often, for lack of proper identifications with species produced bycold grain surface chemistry, these features are considered candidates for production byenergetic processes (UV photons and energetic particles; e.g., Schutte & Khanna 2003, Gibb etal. 2002). The continued search for carriers relies on the availability of laboratory spectra. Basicchemistry (Theule et al. 2013), cometary ices (Mumma & Charnley 2011), and gas phaseobservations of cloud edges and hot cores (Herbst & van Dishoeck 2009) may be used as aguidance in the search for new carriers of the interstellar ice features. In the identificationprocess with laboratory spectra, the widest possible spectral range must be considered (in thetelluric windows and ISO, Spitzer, and future JWST wavelength ranges). Also, appropriateinterstellar targets must be considered because the ice composition is known to varyconsiderably.

REFERENCES• Boogert ACA, Gerakines PA, Whittet DCB, Annual Review of Astronomy and

Astrophysics 53, 2015 (submitted)• Gibb EL, Whittet DCB, ApJL 566, 113 (2002)• Herbst E, van Dishoeck EF, Annual Review of Astronomy and Astrophysics, 47, 427

(2009)• Mumma MJ, Charnley SB, Annual Review of Astronomy and Astrophysics 49, 471

(2011)• Schutte WA, Khanna RK, A&A 398, 1049 (2003)• Theule P, Duvernay F, Danger G, et al., Advances in Space Research 52, 1567 (2013)

Kuiper Belts - Cradles of Cosmic Life

Prof. Dr. Ralf I. Kaiser

Department of Chemistry W.M. Keck Research Laboratory in Astrochemistry

University of Hawaii at Manoa, Honolulu, HI 96822, USA

http://www.chem.hawaii.edu/Bil301/welcome.html http://www.chem.hawaii.edu/Bil301/KLA.html

Kuiper Belt Objects (KBOs) have emerged in their critical role to understand the chemical evolu-tion of the Solar System and how the molecular precursors to life formed and came together to create environments such as on early Earth. KBOs are small planetary bodies orbiting the sun be-yond the planet Neptune, which are among the least modified, most primitive objects in the Solar System. A study of KBOs is important because they are keys to understand the evolution of mat-ter in the early Solar System and are considered as ‘natural time capsules’ at a frozen stage before life developed on Earth. Since dynamical processes exist, which move material residing in the Kuiper Belt into the inner Solar System, this may well play a role in delivering biorelevant molecules to early Earth. As KBOs are windows into the dawn of our Solar System, deciphering the underlying chemistry of KBOs is therefore central to the understanding of the Origins of Life.

In our laboratory, this understanding is achieved by studying the radiation-induced formation of key classes of biorelevant molecules central to the Origins of Life in ices of Kuiper Belt Objects (KBOs) from simple precursor molecules (water, methane, ammonia, carbon monoxide, carbon dioxide, nitrogen, methanol) by reproducing the space environments in a next generation space simulation chamber. Biorelevant molecules are identified on line and in situ by a unique suite of tools which have never been assembled together previously. While functional groups of organic molecules in the condensed phase will be accessible via state of the art infrared, Raman, and UV/VIS spectroscopy, individual biorelevant molecules formed in the ices are probed via isomer-selective reflectron time-of-flight mass spectrometry exploiting soft photo ionization with tunable vacuum ultraviolet light generated via four-wave mixing schemes. Considering that Kuiper Belts have been observed around stars like Fomalhaut and Vega outside our Solar System as well, this knowledge can be transferred to extrasolar planetary systems with Kuiper Belt analog structures thus revolutionizing our understanding of the origin of cosmic life as we know it and eventually revealing the molecular birthplace of life.

This endeavor comes at an exciting time for space exploration. The New Horizons spacecraft is currently en route to Pluto (2015), the most prominent member of the Kuiper Belt; the Rosetta mission is at the very moment orbiting 67P/Churyumov–Gerasimenko – a short period comet from the Kuiper Belt. Both spacecrafts carry out a search for (precursors of) biorelevant mole-cules. Since Rosetta’s lander Philae touched down on 67P/Churyumov–Gerasimenko, data on the molecular composition of the comet’s surface can be directly compared with the inventory of biorelevant molecules extracted from our experiments thus defining the first inventory of biorele-vant molecules, which forms the nucleus for evolution of life in our Solar System billions of years ago.

FORMATION OF MOLECULES OF ASTROBIOLOGICAL RELEVANCE BY SURFACE

HYDROGENATION REACTIONS UNDER DENSE MOLECULAR CLOUD CONDITIONS

S. Ioppolo1, G. Fedoseev

2, T. Lamberts

2, 3, H. M. Cuppen

3, and H. Linnartz

2

1 Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK

2 Sackler Laboratory for Astrophysics, Leiden Observatory, University of Leiden, Leiden NL2300 RA, NL

3 Institute for Molecules and Materials, Radboud University Nijmegen, Nijmegen NL6500 GL, NL

Fax: +31-(0)71-5275819 / Tel: +31-(0)71-5275804 / Email: linnartz@strw.leidenuniv.nl

The unambiguous identification of nearly 200 molecular species in different astronomical

environments proves that our cosmos is a ‘Molecular Universe’. It is currently accepted that ice-

covered dust grains play a key role in the chemistry of the interstellar medium. The cumulative

outcome of recent observations, laboratory studies, and astrochemical models indicates that there

is a strong interplay between the gas and the solid phase throughout the process of forming

molecules in space [1, 2]. Small and mainly unsaturated species can be created in the gas phase.

However, surface reaction mechanisms on cold dust grains initiate molecular chemistry through

the formation of H2, and likely dominate the formation of COMs (e.g., sugars and amino acids)

in space. Indeed, interstellar grains provide surfaces on which gas-phase species can accrete,

meet, and react, and to which they can donate excess energy. Therefore, in dense cold clouds, icy

dust grains act both as a molecular reservoir and as sites for catalysis.

In the last decade, laboratory work showed that molecules like H2O, CO2, CH3OH, H2CO,

HCOOH, and NH3 are efficiently formed through non-energetic atom addition reaction on cold

ice grains [3-7]. However, more complex molecule formation has always been thought to be

triggered largely by cosmic ray induced UV photon irradiation, and thermal processing [8]. Here,

I present the first laboratory results on the formation of molecules of astrobiological importance

– hydroxylamine (NH2OH), glycolaldehyde (HC(O)CH2OH), and ethylene glycol

(H2C(OH)CH2OH) – by non-energetic surface hydrogenation of NO and CO containing ices,

respectively [9-13]. These experiments aim at simulating the CO freeze-out stage in interstellar

dark cloud regions, well before thermal and energetic processing become dominant. My talk

reviews the most recent work performed at the Sackler Laboratory for Astrophysics in Leiden

(NL). The experimentally established new reaction pathways are implemented into astrochemical

models to study their impact on the interstellar ice evolution under much longer timescales

(105 yr) than possible in the laboratory.

REFERENCES

[1] Herbst and van Dishoeck 2009, ARAA, 47, 427. [2] Garrod 2013, ApJ, 765, 60. [3] Ioppolo,

Cuppen, Romanzin, van Dishoeck, Linnartz 2008, ApJ, 686, 1474. [4] Ioppolo, van Boheemen,

Cuppen, van Dishoeck, Linnartz 2011, MNRAS, 413, 2281. [5] Fuchs, Cuppen, Ioppolo et al.

2009, A&A, 505, 629. [6] Ioppolo, Cuppen, van Dishoeck, Linnartz 2011, MNRAS, 410, 1089.

[7] Fedoseev, Ioppolo, Zhao, Lamberts, Linnartz 2015, MNRAS, 446, 439. [8] van Dishoeck

and Blake 1998, ARAA, 36, 317. [9] Congiu, Fedoseev, Ioppolo et al. 2012, ApJL, 750, 12. [10]

Fedoseev, Ioppolo, Lamberts et al. 2012, JCP, 137, 4714. [11] Minissale, Fedoseev, Congiu et al.

2014, PCCP, 16, 8257. [12] Ioppolo, Fedoseev, Minissale et al. 2014, PCCP, 16, 8270. [13]

Fedoseev, Cuppen, Ioppolo, Lamberts, Linnartz 2015, MNRAS in press.

Long-lived Coherent Dynamics Induced by Cosmic Microwave Background Radiation

Timur Tscherbul and Paul Brumer

Chemical Physics Theory Group

University of Toronto

Toronto, Ontario, Canada

Fax: 416-978-5325

Telephone: 416-978-3569

Email: pbrumer@chem.utoronto.ca

Quantum coherences generated in molecules due to excitation by incoherent blackbody radiation

is of considerable interest in a number of research areas. As a means of determining the influence

of the coherence time of the radiation on such processes, we have examined Rydberg atom

excitation by the cosmic microwave background, an environment with the longest coherence

time of any natural radiative process. Resultant theoretical results, obtained by solving non-

Markovian equations of motion with no free parameters, show that the atoms display long lived

quantum coherences and associated quantum beats in fluorescence on the time scale of tens of

picoseconds. An analytic model exposes the dependence of coherent dynamics on the energy

splitting between atomic eigenstates, transition dipole moments, and the coherence time of the

radiation. Experimental detection of the fluorescence quantum beat signal from a trapped

ensemble of 108 Rydberg atoms will be discussed, but shown to be technically challenging at

present. Further studies on model systems show the significance of Fano interferences in

obtaining long lived coherences, particularly in the regime where the molecular level spacing is

smaller than the radiative line width.

References: T. Tscherbul and P. Brumer, Phys. Rev. A 89, 013423 (2014)

T. Tscherbul and P. Brumer, Phys. Rev. Lett. 113, 113601 (2014)

Energetic Gas-Surface Encounters at Ice and Organic Interfaces

Wenxin Li, G. Langlois, K. Gibson, N. Kautz, D. Killelea and Steven J. Sibener James Franck Institute & Dept. of Chemistry, University of Chicago, Chicago, IL 60637

Email: s-sibener@uchicago.edu; Tel: 1-773-702-7193

The interaction of energetic atomic and molecular species with water and ice is of fundamental importance for astrophysical chemistry, as are the interactions of atomic reagents in reactive heterogeneous systems. Our initial efforts in ice chemistry, involving both experiment and numerical simulations, demonstrated that translational energy activates the embedding of Xe and Kr atoms in the near surface region of ice surfaces [1-3]. These studies revealed a rich palette of dynamics that are dependent upon the kinetic energy of the gas-surface encounter, the size and mass of the incident specie, as well as the nature of the ice itself; differing dynamics are seen for crystalline ice in comparison to amorphous solid water. During the past two years we have substantially expanded these studies to include the energetic embedding dynamics of molecular systems, namely CF4 [4] and most recently CO2, with ice interfaces using a combination of in situ FTIR, scattering, and desorption measurements. CF4 and CO2 with high translational energies (≥ 3 eV) were observed to embed in amorphous solid water. Just as with Xe and Kr, the initial adsorption rate is strongly activated by translational energy, with the embedding probabilities for both molecules being less than that for Kr and Xe. At Ei = 3 eV, the embedding probability for Xe and Kr is ~5x10-4, for CF4 ~5x10-5, and for CO2 ~10-6. The new CO2/ice system is of particular interest because of its fundamental role in the Earth’s aqueous, atmospheric, permafrost, and seabed geosciences, as well as in the interstellar and circumstellar regions. IR spectra of embedded CO2 reveal two peaks, at ~2341 cm-1, and at 2361 cm-1, which indicate changes in bonding for the embedded CO2 as well as in the formation of local CO2 dimers or clusters, respectively. These results show that energetic ballistic embedding in ice is a general phenomenon, and represents a significant new channel by which incident species can be trapped under conditions where they would otherwise not be bound stably as surface adsorbates. These findings have implications for many fields including environmental science, trace gas collection and release, and the composition of astrophysical icy bodies in space. If time permits, further discussion will also be devoted to the reaction mechanisms that we observe for O(3P) reacting with saturated [5] and unsaturated/aromatic adsorbed hydrocarbons [6]. 1. Energetic Ballistic Deposition of Volatile Gases into Ice, K. D. Gibson, Daniel R. Killelea, James S. Becker, Hanqiu Yuan, and S. J. Sibener, Chem. Phys. Lett., 531 18-21 (2012). 2. Scattering of High-Incident-Energy Kr and Xe from Ice: Evidence That a Major Channel Involves Penetration into the Bulk, K. D. Gibson, Daniel R. Killelea, Hanqiu Yuan, James S. Becker, Subha Pratihar, Paranjothy Manikandan, Swapnil C., Kohale, W. L. Hase, S. J. Sibener, J. Phys. Chem. C, 116, 14264-14273 (2012). 3. Chemical Dynamics Simulations of High Energy Xenon Atom Collisions with the (0001) Surface of Hexagonal Ice, S. Pratihar, S. C. Kohale, L. Yang, P. Manikandan, K. D. Gibson, D. R. Killelea, H. Yuan, S. J. Sibener, and W. L. Hase, J. Phys. Chem. C, 117, 2183-2193 (2013). 4. Molecular Interactions with Ice: Molecular Embedding, Adsorption, Detection and Release, K. D. Gibson, Grant G. Langlois, Wenxin Li, Daniel R. Killelea, and S. J. Sibener; Invited Feature Article - The Journal of Chemical Physics 141, 18C514/1-10 (2014). 5. Modification of Alkanethiolate Monolayers by O(3P) Atomic Oxygen: Effect of Chain Length and Surface Temperature, Hanqiu Yuan, K. D. Gibson, Wenxin Li, and S. J. Sibener, J. Phys. Chem. B 117, 4381-4389 (2013). 6. Formation of Stabilized Ketene Intermediates in the Reaction of O(3P) with Oligo(phenylene ethynylene) Thiolate Self-Assembled Monolayers on Au(111), Wenxin Li, Grant G. Langlois, Natalie A. Kautz, and S. J. Sibener, J. Phys. Chem. C 118, 15846-15852 (2014).

VUV PHOTOLYSIS OF SOLID METHANE

Bing-Ming Cheng

National Synchrotron Radiation Research Center, Hsinchu Science Park, Hsinchu 30076, Taiwan

Fax:+886-3-5783813/Tel:+886-3-5780281/Email: bmcheng@nsrrc.org.tw

ABSTRACT

In some space objects, methane is observed at small proportions; for examples, the

concentrations of methane are 1.6, 4.7, and 0.2~1.45 % on Titan, young stellar objects and

comets, respectively. In other astronomical objects, methane exists in clouds like water clouds on

Earth; the cycling of methane clouds condenses methane into lakes or oceans in astronomical

environments, similar to water on Earth. From observations from radar imaging of spacecraft

Cassini on Titan, Stofan et al. discovered more than 75 radar-dark patches attributed to liquid

methane lakes (Nature, 2007, vol. 445, 61); this evidence demonstrates convincingly the

existence of pure condensed methane in astronomical environments. The melting point of

methane is about 90 K; liquid methane freezes in cold outer space where temperatures are less

than 40 K, at which methane is known to exist in a solid form. Photons in vacuum-ultraviolet

light and energetic particles incident on molecular solids analogously induce varied effects in

astrophysical environments. The photolysis of CH4 with vacuum-ultraviolet light undoubtedly

serves as an initial process in the evolution of hydrocarbons in space. With light of wavelength

120-200 nm selected from a synchrotron source, we irradiated samples of solid methane at 3 K.

After irradiation on pure solid methane, four distinct products -- CH3, C2H2, C2H4 and C2H6 –

were identified according to their characteristic infrared absorption lines. The distribution among

these products depended on the wavelength of irradiation. We observed all four products upon

excitation at 121.6, 130 and 140 nm, C2H2 and C2H6 at 155, 165 and 175 nm, and only C2H2 at

185 and 190 nm. No product was observed after irradiation at 200 nm. In contrast, photolysis of

methane dispersed in solid neon at 121.6 nm, at ratios 1:100 to 1:10,000, yielded many more

products, comprising CH3, C2H2, C2H3, C2H4, C2H6, C4H2, C4H4, C5H2 and C8H2, CnH (n=1-5),

and carbon chains Cn (n=3-20); not only the production but also the yield of carbon agglomerates

increased with a decreasing initial concentration of methane dispersed in solid neon. For

example, at CH4:Ne = 1:100, the products with 121.6 nm were stable molecules C2H2, C2H4,

C2H6, C4H2, and radicals CH3, C2H3, C3H, C4H, C5H, C6; whereas, at CH4:Ne = 1:10,000, the 30

products included stable molecules C2H2, C2H4, C2H6, C4H2, C4H4, oxides CO and C5O, hydride

radicals CH, CH3, C2H3, C2H, C3H, C4H, C5H, C5H2, C8H2, and carbon chains C3, C4, C5, C6, C7,

C8, C9, C10, C11, C12, C14, C16, C18, and C20. The photolysis of methane in a solid sample is thus

affected to a large extent by the environment of the methane molecules. The comparison with the

photochemistry of methane dispersed in neon exposes another disparity regarding a dissociation

threshold. No product of photolysis of methane was detectable on irradiation of methane

dispersed in neon at wavelength larger than 150 nm, whereas methane was photolyzed to

produce C2H2 at 190 nm in a pure solid state. A novel finding in our present work is that the

largest wavelengths at which products C2H6, C2H4 and C2H2 were generated were 175, 140 and

190 nm, respectively, through a radiative process: the greatest molecular disruption occurred

with the photons of least energy. Our photochemical experiments on solid methane are thus

directly applicable to space environments. Information about the dissociation of CH4 at low

temperature with photons of varied energy has implications for astrophysical environments.

Formation and Isomer-Specific Detection of Complex Organic Molecules in

Astrophysical Ice Analogs

Matthew Abplanalp, Brant Jones, Ralf Kaiser

Department of Chemistry, University of Hawai’i at Manoa, Honolulu, HI 96822

W.M. Keck Research Laboratory in Astrochemistry, University of Hawai’i at Manoa, Honolulu, HI 96822

Email: mja38@hawaii.edu; brantmj@hawaii.edu; ralfk@hawaii.edu

ABSTRACT

We present results from the W.M. Keck Research Laboratory in Astrochemistry on the formation

of complex organic molecules starting from simple ice mixtures of carbon monoxide (CO) and

simple hydrocarbons (C2H4 or C2H6) upon interaction of the ices with ionizing radiation.

Specifically, a reflectron time-of-flight mass spectrometer coupled with soft vacuum ultraviolet

tunable photoionization was used to discriminate between complex organic isomers, such as

propanal/cyclopropanone (C3H4O) and acetone/propanal (C3H6O). The use of soft tunable

photoionization allows for the parent molecular ion to be produced from sublimed molecules

formed within the processed ice without fragmentation, and also for specific molecules to be

detected based upon their unique ionization energies. Selective isotopologue ices were also used

to unambiguously determine which molecules were formed. Several molecules existing as ices

consisting of H2O, CO, CO2, CH3OH, NH3, and CH4 have been detected in the interstellar

medium and are subject to chemical processing due to galactic cosmic rays, UV photons, and

other forms of ionizing radiation. This research focuses on understanding the evolution of analog

ices by simulating the chemical processing via ionizing radiation in an ultrahigh vacuum

chamber while analyzing the system online and in situ with several spectroscopy methods in the

ice (UV-Vis, FT-IR, Raman) as well as the sublimed gas products during temperature

programmed desorption studies (QMS, ReTOF-PI). These studies can provide a detailed

description of the molecules that are formed from the processing of interstellar analog ices.

Reflectron Time-of-Flight mass spectrum as a function of temperature for the newly formed species from

the energetic processing of carbon monoxide (C18

O) – ethylene (C2D4) ice at a photoionization energy of

10.49 eV.

PHOTOIONIZATION DYNAMICS, MOLECULAR GROWTH AND NUCLEATION WITH

MOLECULAR BEAMS AND SYNCHROTRON RADIATION

Biswajit Bandyopadhyay, Yigang Fang, Oleg Kostko & Musahid Ahmed

MS 6R 2100, Lawrence Berkeley National Laboratory, Berkeley, CA-94720

510-486-5311/510-486-6355/mahmed@lbl.gov

ABSTRACT

The photoionization dynamics of clusters is of paramount interest in a number of fields spanning

biology, chemistry, and physics. Understanding the changes in electronic structure that occur in

these ionic clusters is critical to unveil their structure and function and is important in fields as

diverse as cloud nucleation in the earth and planetray atmospheres, radiation biology, and

catalysis. Coupled with electronic structure calculations, photoionization mass spectrometry with

tunable VUV synchrotron radiation provides for insight into diverse processes such proton

transfer in solvated DNA nucleobases,1 fragmentation in strongly hydrogen bonded ionic

systems,2 and elucidation of potential energy surfaces.3 I will discuss this and also highlight new

directions in probing molecular growth and nucleation in ion and neutral cluster systems.

We have recently developed an experimental strategy for characterizing neutral versus ion-

induced growth using in-source ionization of molecular beams with tunable VUV synchrotron

radiation. Methanol was chosen as a model system (since our group had extensively studied its

VUV photoionization processes) and by varying the distance between ionization and source, a

new method of studying molecular growth was enabled. The dominant distribution are

protonated methanol clusters (CH3OH)nH+), followed by protonated methanol-water

((CH3OH)n)(H2O)H+) and protonated methanol-dimethyl ether ((CH3)2O(CH3OH)nH+) clusters.

The intensity distributions show signatures for both ion induced and neutral growth, and can be

qualitatively modelled by Thomson’s liquid drop model.4 I will discuss these results and also

show molecular growth processes in acetylene/ethylene clusters.

REFERENCES

1) K. Khistyaev, A. Golan, K. B. Bravaya, N. Orms, A. I. Krylov, and M. Ahmed, “Proton

transfer in nucleobases is mediated by water,” J. Phys. Chem. A., (2013) 117, 6789 2) F. Bell, Q. N. Ruan, A. Golan, P. R. Horn, M. Ahmed, S. R. Leone, and M. Head-Gordon,

“Dissociative Photoionization of Glycerol and its Dimer Occurs Predominantly via a Ternary Hydrogen-Bridged Ion-Molecule Complex,” J. Am. Chem. Soc., (2013) 135, 14229

3) M. Perera, R. B. Metz, O. Kostko, and M. Ahmed, “Vacuum Ultraviolet Photoionization

Studies of PtCH2 and H-Pt-CH3: A Potential Energy Surface for the Pt + CH4 Reaction,”

Angew. Chem. Int. Ed., (2013) 125, 922 4) B. Bandyopadhyay, Y. Fang, O. Kostko, and M. Ahmed, “In-Source VUV Ionization

Induces Nucleation in a Molecular Beam of Methanol” (To be submitted)

Extended Hydrogen Microwave discharge lamp studies for laboratory applications  

Niels Ligterink1, Daniel Paardekoper1, Harold Linnartz1 1Sackler Laboratory for Astrophysics, Leiden Observatory, Leiden University 

 In various regions of the interstellar medium, such as cold dark clouds and protoplanetary disks, where cosmic ray induced H2                                       emission yields vacuum UV photons, ice covered dust grains will undergo photo­induced physical and chemical processes. In                                 the laboratory such light has been simulated for decades using hydrogen microwave discharge lamps. These lamps are intense                                   and cover the range between 115 to 200 nm, specifically Lyman­alfa transitions at 121 nm and several molecular hydrogen                                     transitions around 160 nm. However, in the past years it has become more and more apparent that a more systematic characterization of these lamps is                                         necessary to compare quantitative results from different laboratories [Chen et al. 2014]. Clearly, emission features depend on a                                   number of parameters, such as H2 pressure, gas mixture, MW power, lamp and cavity design. Given the wavelength dependent                                     nature of some processes, such as ice photodesorption [Fayolle et al. 2011] it is important that the parameters determining the                                       lamp operation are fully understood.  Here we present new results, confirming findings by Chen et al 2014, but also extending on these, using a vacuum UV                                         spectrometer as available at the Leibniz Institut für Plasmaforschung und Technologie (INP Greifswald) [Foest et al. 2007]. This                                   spectrometer is highly precise both in wavelength and absolute intensity, using a calibrated D2 DC lamp. We will show settings                                       for which the lamp provides a higher output and how to manage the 121/160 band ratios in a way that this helps to interpret                                               photodesorption efficiencies [Öberg et al. 2009, Muñoz­Caro et al. 2010], measured in different groups, in a consistent way.  Y.­J. Chen, K.­J. Chuang, G. M. Muñoz Caro et al. 2014, APJ 781:15 E.C. Fayolle, M. Bertin, C. Romanzin et al. 2011, APJL 739:L36 R. Foest, E. Kindel , H. Lange et al. 2007, Contrib. Plasma Phys. 47, No. 1­2, 119 – 128 K.I. Öberg, E.F. van Dishoeck, H. Linnartz, 2009, A&A 496, 281­293 G.M. Muñoz­Caro, A. Jiménez­Escobar, J.Á. Martín­Gago et al. 2010, A&A 511, A108 We thank INP Greifswald (www.inp­greifswald.de) and especially Mr. Holtz for making the measurements presented here                             possible.  Contact or more information: ligterink@strw.leidenuniv.nl 

 Figure 1. Three spectra showing the differences between a lamp running on pure H2 and two lamps running on a H2:He or D2:He                                             mixture. These spectra clearly show the increase in the Lyman­alfa component after helium addition and suppresion of                                 molecular bands. 

CHEMICAL EVOLUTION OF ASTROPHYSICAL AND PLANETARY ICE ANALOGS

UNDER RADIATION: IN-SITU TWO-COLOR LASER ABLATION AND IONIZATION

MASS SPECTROMETRY (2C-LAIMS)

Bryana L. Henderson and Murthy S. Gudipati*

Ice Spectroscopy Lab, Science Division, Jet Propulsion Laboratory, California Institute of

Technology, Pasadena, CA 91109, USA.

Fax: +1-818-393-4445; Tel: +1-818-354-2637; *E-mail: gudipati@jpl.nasa.gov

ABSTRACT

Studying the chemical evolution of ices in the interstellar medium and around stars at different

stages of their lives provides insight into the formation and evolution of complex organics under

radiation and the likelihood of their survival and transport to Earth-like planets.

Traditional spectroscopic methods (ultraviolet, infrared, and fluorescence) have contributed

significantly to enhance our understanding of the evolution of ices and organics in the Universe

(Allodi et al. 2013; Herbst 2014). However, these techniques have some limitations and search

for complementary techniques has begun recently (Gudipati & Yang 2012). Two-color laser

ablation and laser ionization mass spectrometry (2C-LAIMS), demonstrating that chemical

evolution of ices and impurities therein can be monitored by generating plumes of these ices and

subjecting the plumes to multiphoton ionization (MPI), has paved a path for new complementary

methods (Henderson & Gudipati 2014a; Henderson & Gudipati 2014b; Yang & Gudipati 2014).

Other similar works are also emerging to probe and understand the chemistry and composition of

ices (Maity, Kaiser, & Jones 2014; Paardekooper et al. 2014), indicating the importance of time-

of-flight mass spectrometry in understanding the chemical evolution of astrophysical and

planetary ice analogs.

In this talk we will discuss the effect of photons vs. electrons on water-rich ices containing the

most common carbon-containing molecule methanol (CH3OH) and nitrogen-containing molecule

ammonia (NH3). We found that even under the coldest temperatures studied (5 K) electron or

photon irradiation of these ices leads to production of several complex organics, many of which

are observed in the interstellar ices as well as in cometary outgassing.

Acknowledgments: This work has been conducted at the Jet Propulsion Laboratory, California

Institute of Technology under a contract with the National Aeronautics and Space

Administration. Funding from NASA Planetary Atmospheres and Cassini Data Analysis

Programs and NASA Postdoctoral Fellowship to BLH is gratefully acknowledged.

References

Allodi, M. A., et al. 2013, SSRv, 180, 101

Gudipati, M. S., & Yang, R. 2012, The Astrophysical Journal Letters, 756, L24

Henderson, B. L., & Gudipati, M. S. 2014a, ApJ, (accepted for publication)

Henderson, B. L., & Gudipati, M. S. 2014b, J Phys Chem A, 118, 5454

Herbst, E. 2014, PCCP, 16, 3344

Maity, S., Kaiser, R. I., & Jones, B. M. 2014, ApJ, 789

Paardekooper, D. M., Bossa, J. B., Isokoski, K., & Linnartz, H. 2014, RScI, 85

Yang, R., & Gudipati, M. S. 2014, J Chem Phys, 140, 104202 (7pp)

FOLLOWING THE CHEMICAL HISTORY OF STELLAR EJECTA THROUGH

ASTRONOMICAL OBSERVATONS AND LABORATORY SPECTROSCOPY

L.M. Ziurys, D.T. Halfen, J.L. Edwards, J. Min, and D.R. Schmidt

Department of Chemistry and Biochemistry, Department of Astronomy and Steward

Observatory, Arizona Radio Observatory, University of Arizona, Tucson, AZ 85721

520-621-5554/520-621-6525/lziurys@email.arizona.edu

ABSTRACT Mass loss from circumstellar envelopes of evolved stars and the more advanced, planetary nebulae (PNe)

stage, is a major avenue by which the interstellar medium (ISM) is enriched in gas, dust, and the heavier

elements. The chemical and physical characteristics of circumstellar shells and subsequent PNe thus have

major impact on the overall life cycle of dense material in the ISM, as well as determining Galactic

chemical evolution. Through a combined observational and laboratory program, we have been

investigating the chemistry of such envelopes and the subsequent planetary nebula phase. The laboratory

aspect has centered on high resolution rotational spectroscopy of molecules possibly associated with these

regions, using a combination of direct absorption and Fourier transform microwave/millimeter-wave

(FTMmmW) techniques. Recent studies have included measurements of the CCN (X2Πr), SH+ (X3Σ-), and

ScO (X2Σ+) radicals. Observational work includes searches for these molecules and other species in

circumtellar environments, and in various planetary nebulae, using the telescopes of the Arizona Radio

Observatory. CCN has now been identified in the carbon-rich envelope of IRC+10216 with an abundance

of f0 ~ 6 × 10-8, resulting in a [CN]/[CCN]/[C3N] ratio of ~ 500:1:50. Furthermore, studies of

PNe have resulted in the detection of numerous polyatomic species in older nebulae, including

HNC, SO2, N2H+, H2CO, and CCH, in complete contradiction to model calculations. This result

suggests that some significant fraction of the molecular content of circumstellar shells survives into the

late stages of the PNe phase, and is being recycled into the diffuse ISM. Interstellar molecules therefore

appear to be far more robust than theoretically predicted, and can be abundant in regions thought to be

overwhelmingly atomic in composition.

PHOTOSTABILITY OF ORGANICS IN LOW EARTH ORBIT: RESULTS FROM

SPACE EXPOSURE PLATFORMS AND NANOSATELLITES

Pascale Ehrenfreund1,2

, Andreas Elsaesser1, Arthur Stok

1, Euan Monaghan

1, Richard C. Quinn

3,

Antonio J. Ricco4, Andrew L. Mattioda

4, Amanda Cook

4, Farid Salama

4, K. Bryson

4, Bernard

Foing5

1Leiden Observatory, 2300 RA Leiden, NL,

2Space Policy Institute, Washington DC, USA,

3Carl

Sagan Center, SETI Institute, 189 Bernardo Ave, Suite 100, Mountain View, CA, 94043, USA, 4NASA Ames Research Center, Moffett Field, CA, USA,

5ESA/ESTEC, Noordwijk, NL, email:

pehren@gwu.edu

ABSTRACT

The study of the reactions, destruction, and longevity of organics in the space environment is of

fundamental interest. To provide an accurate outer space environment for extended durations,

exposure experiments in low Earth orbit have been conducted in the last decades in order to

examine the consequences of actual space conditions including combinations of solar and cosmic

radiation, space vacuum, and microgravity. A series of successful experiments performed on

International Space Station (ISS) external platforms have provided insights into the evolution of

organic and biological materials in space and planetary environments. The O/OREOS

(Organism/ORganic Exposure to Orbital Stresses) nanosatellite studied in situ during the 6-

month primary and 1-year extended mission the photochemical processing of the PAH

isoviolanthrene, the quinone anthrarufin (1,5-dihydroxyanthrarquinone), and iron

tetraphenylporphyrin chloride in low Earth orbit (650 km altitude); results were autonomously

telemetered to Earth. We report on the methods and flight preparation of samples for space

exposure platforms and results on the stability of organic thin-films. We also present laboratory

experiments investigating the photostability of the anthraquinone derivative anthrarufin and its

interaction with iron oxide thin-films, namely magnetite and hematite. The UV-vis degradation

process of anthrarufin thin-films was recorded over time, which revealed intriguing and counter-

intuitive photolytic kinetics that will be re-investigated on the ISS in a space environment.

Laboratory Studies of Astronomical Ices at the NASA Goddard Space Flight Center: Past Successes, Present Efforts, and Future Perspectives

Reggie L. Hudson, Perry A. Gerakines, and Mark J. Loeffler

Astrochemistry Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 Fax: (301) 286-0440 Tel: (301) 286-6961 Email: reggie.hudson@nasa.gov

Web: http://science.gsfc.nasa.gov/691/cosmicice/

ABSTRACT

NASA has supported an active laboratory research program to study the chemistry and spectroscopy of astronomical ices for over 30 years at the Goddard Space Flight Center. Our group's earliest work, and that in the recent past, helped to establish chemical and physical phenomena in ices that are still being studied and led to predictions later verified by astronomical observers and expanded upon by others. More specifically, radiation-chemical and spectroscopic methods have been used to provide insight into the expected evolution of icy materials within and beyond the Solar System, motivated by potential applications to NASA-related, and NASA-funded, projects. This presentation will begin with a brief review of our research group's original purpose and goals, followed by several examples of current research into irradiated ices, such as relate to Jovian cloud chemistry and Martian astrobiology. Both published and unpublished results will be presented. In the final part of the presentation the speaker will offer a few brief perspectives and predictions for the near future of the field.

SELECTED RECENT WORK Hudson, R. L., Ferrante, R. F., and Moore, M. H. (2014). Infrared Spectra and Optical Constants of Astronomical Ices: I. Amorphous and Crystalline Acetylene. Icarus, 228, 276-287. Hudson, R. L. and Loeffler, M. J. (2013). Ketene Formation in Interstellar Ices: A Laboratory Study. The Astrophysical Journal, 773, 773-782. Gerakines, P. A., Hudson, R. L., Moore, M. H., and Bell, J-L. (2012). In-situ Measurements of the Radiation Stability of Amino Acids at 15 - 140 K. Icarus, 220, 647-659. Loeffler, M., Hudson, R. L., Moore, M. H., and Carlson, R. W. (2011). Radiolysis of Sulfuric Acid, Sulfuric Acid Monohydrate, and Sulfuric Acid Tetrahydrate and its Relevance to Europa. Icarus, 215, 370-380. Peeters, Z., Hudson, R.L., Moore, M.H., and Lewis, A. (2010). The Formation and Stability of Carbonic Acid on Outer Solar System Bodies. Icarus, 210, 480-487.

VUV spectroscopy of carbonaceous dust analogues relevant to the interstellar medium

Lisseth Gavilan1*, Ivan Alata1,2, Thomas Pino1,2, Emmanuel Dartois1

1Institut d’Astrophysique Spatiale (IAS), UMR 8617,

Université Paris Sud, bâtiment 121, 91405 Orsay, France 2Institut des Sciences Moléculaires d’Orsay (ISMO), UMR 8214,

Université Paris Sud, bâtiment 210, 91405 Orsay, France

*Email: lisseth.gavilan@ias.u-psud.fr

ABSTRACT

At the IAS and ISMO laboratories (Université Paris Sud, France), we produce analogues to carbonaceous interstellar dust encountered in various phases of the interstellar medium: amorphous hydrogenated carbons (a-C:H) and soots. The a-C:Hs were produced using an R.F. plasma reactor at low pressures, and their structure is dominated by an aliphatic skeleton1. The soots have been produced in an ethylene (C2H4) flame and provide samples dominated by a polyaromatic carbon skeleton2. We have measured thin films (<100 nm) of these analogues in transmission in the far ultraviolet (190 - 250 nm) and in the vacuum ultraviolet (50 - 190 nm) regions using the DISCO/APEX beamline of the SOLEIL synchrotron. These materials were also characterized via infrared microscopy on the SMIS beamline. These measurements enable the derivation of optical constants and photo cross-sections used to improve models of the photochemistry of these materials in astrophysical environments. The relation between the IR and UV spectral properties of these materials and their astronomical counterparts will be discussed.

REFERENCES

1. E. Dartois, G. M. Muñoz Caro, D. Deboffle, et al. « Ultraviolet photoproduction of ISM dust: Laboratory characterisation and astrophysical relevance » , A&A 432, 895–908 (2005)

2. Y. Carpentier, G. Féraud, E. Dartois, et al. « Nanostructuration of carbonaceous dust as seen through the positions of the 6.2 and 7.7 µm AIBs », A&A 548, A40 (2012)

WHAT CONTROLS THE DIFFUSION MECHANISM OF HYDROGEN ATOM ON ICE?

Naoki Watanabe, Tetsuya Hama, Kazuaki Kuwahata, Akira Kouchi

Institute of Low Temperature Science, Hokkaido University, Sapporo, Hokkaido 060-0819,

JAPAN

Email: watanabe@lowtem.hokudai.ac.jp In molecular clouds, the accretion rate of hydrogen atom on dust is considered to be very low,

something like 1 atom per days, so that the surface number density of H atoms is very limited. In

such a situation, significant surface diffusion of H atoms is necessary to encounter reaction

partners on dust. Therefore, investigating the diffusion mechanism of H atom on ice in various

conditions is indispensable to understand chemical evolution. There have been many reports on

the surface diffusion of H atom on amorphous solid water (ASW). After debate for a period of

years, as long as we understand, some consensus has been reached for the H-atom diffusion on

ASW (see, as a review, refs [1,2]): 1. The ASW surface consists of various adsorption sites with different potential depths, leading

to the distribution of activation barriers for diffusion;

2. Diffusion mechanism on ASW can be represented by classical thermal hopping over the

barriers of ~20 meV at low coverage (<10-2) of H atoms although tunneling diffusion cannot

be excluded;

3. Very shallow potential sites providing the activation barrier of <18 meV for diffusion

dominate the ASW surface.[3]

The above knowledge was derived from H-H recombination rates in TPD experiments or those

estimated from the attenuation of surface H-atoms after given amounts of H atoms predeposited.

In these experiments, the number of H atoms prepared on the surface tends to be low and thus

recombination would require H atoms to diffuse over relatively long distance. It is reasonable to

consider that longer diffusion makes atoms have more chance to be trapped at the deep

adsorption potential sites. In other words, the diffusion rate observed in these experiments would

be limited by the diffusion over the deep sites. We expect that when H atoms locate nearby each

other, those can meet through short diffusion over the dominant shallow sites without trapped in

the deep sites. In such a situation, the diffusion rate and mechanism would appear differently

from previous experiments.

We recently performed a new experiment in which H- or D-atom number densities on ASW and

polycrystalline ice were measured during atomic deposition at various fluxes. In this experiment,

the number density of H (D) atoms on the surface can be changed by the flux deposited. At

higher number densities (higher fluxes), recombination through short-distance diffusion can be

monitored unlike the previous works. Our results demonstrate that the observed diffusion

mechanism (tunneling or thermal) and rates depend on the diffusion length and the morphology

of ice surfaces. During the atomic deposition, the number density of H atoms was found to differ

from that of D atom even though the fluxes are the same. It means that we should be careful to

compare hydrogenation and deuteration rates which have been determined experimentally in

previous works. [1] T. Hama & N. Watanabe, Chem. Rev. 113, 8783 (2013)

[2] G. Vidali, Chem. Rev. 113, 8762 (2013)

[3] T. Hama, K. Kuwahata, N. Watanabe, A. Kouchi, Y. Kimura, T. Chigai, V. Pirronello, ApJ

757, 185 (2012)

EXPERIMENTAL APPROACHES TO UNDERSTAND NUCLEATION PROCESS VIA METASTABLE PHASES

Yuki Kimura, Shinnosuke Ishizuka, Kyoko K. Tanaka

Institute of Low Temperature Science, Hokkaido University, Sapporo, Hokkaido 060–0819, Japan

ykimura@lowtem.hokudai.ac.jp

ABSTRACT

Nucleation is a process to form stable particles by self-assembly of atoms, molecules or ions and to overcome a free energy barrier to generate a new surface. Traditionally, it has been believed that the nucleation process is a result of a valance of attachment and detachment of growth units into a stable particle. Against the traditional view, recently, non-classical pathway of the nucleation process has been proposed, e.g., formation via agglomeration of pre-nucleation clusters or metastable phases such as amorphous [1-3]. However, there is a lots of matters for debate. In the nucleation process, it passes through the size of meso-scale. We, therefore, believe physical properties and singular phenomena of nanoparticles must be taken into account to understand the nucleation process and also formation process of cosmic dust particles.

Nucleation is very difficult to visualize in experimentally because of rapid process in nano-scale. In order to understand the nucleation process, we started new experimental projects based on following two approaches; (A) Visualization of nucleation processes from a solution by fluid-reaction transmission electron microscope (TEM), which can be observe the nucleation process from a solution in nanometer scale; (B) In-situ observation of temperature and concentration using an interferometer, and infrared spectra by FT-IR spectrometer during nucleation from a vapor phase. Here, we show our recent results related to formation and evolution of cosmic dust particles accompanying with stellar life.

We succeeded to determine physical parameters, surface free energies and sticking probabilities, of metallic nanoparticles for homogeneous nucleation and show the nucleation process via metastable phases based on the nucleation environment and nucleation theories [4]. Homogeneous nucleation is only able to occur under very high supersaturation and then the size of critical nuclei is only several atoms. The nuclei grow as a melt phase and crystallize stochastically. In case of Mn, both of stable -Mn and metastable -Mn are formed, and the case of Mg-silicate, amorphous and crystalline phases are obtained in the resulting sample. We also performed a nucleation experiment of Fe in micro gravity environment using a sounding rocket and determined the sticking probability, which is as small as 10-4 or less. This value is significantly lower than ~100 obtained by ground based bulk experiment. In the presentation, we will show the possible formation scenario of cosmic dust particles around evolved stars.

REFERENCES [1] Gebauer, D., Volkel, A., Colfen, H. Science, 322 (2008) 1819. [2] Nielsen, M. H. et al. Science, 345 (2014) 1158. [3] Kimura, Y. et al. Journal of the American Chemical Society, 136 (2014) 1762. [4] Kimura, Y. et al. Crystal Growth and Design, 12 (2012) 3278.

Diffusion and Entrapment in Simple Ice Mixtures

Karin I. Öberg

Harvard-Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138, USA

+1-617-496-9062 / koberg@cfa.harvard.edu

Diffusion of atoms, radicals and molecules inside of and on top of icy grain mantles regulate the

morphology of these ices as well as their chemistry. Together with desorption, ice diffusion

therefore underpins both grain-surface and gas-phase chemical compositions in the dense and

cold regions of the interstellar medium. We have carried out a series of experiments aimed at

characterizing diffusion-driven processes such as segregation, mixing, and entrapment in water

and CO-dominated ices. The experiments are performed under UHV conditions at low

temperatures (down to 10 K) and with thin ices to mimic interstellar condition. In this talk I will

first discuss the observations that have motivated these studies, including ice observations with

Spitzer and new gas-phase compositional studies with ALMA. I will review the empirical

constraints provided by our and other related experiments in terms of time scales and barriers for

different kinds of ice diffusion. These results have been used in concert with theory to isolate and

quantify some of the microscopic processes that ultimately drive the observed macroscopic

changes in ice morphology and composition. I will discuss these constraints and how they can be

implemented in astrochemical models.

VACUUM ULTRAVIOLET PHOTON-STIMULATED FORMATION OF CO2 AT

BURIED ICE:GRAPHITE GRAIN INTERFACES

J. Shi1, G. A. Grieves

1, and T. M. Orlando

*1, 2

1School of Chemistry and Biochemistry and

2School of Physics

Georgia Institute of Technology, Atlanta, GA 30332-0400

Phone: (404) 894-4012, Thomas.Orlando@chemistry.gatech.edu

ABSTRACT

The vacuum ultraviolet (VUV) synthesis of carbon dioxide on ice-coated graphite and

isotopic labeled 13

C graphite has been examined for temperatures between 40 and 120 K. The

results show that CO2 can be formed at the buried ice:graphite interface with Lyman-α photon

irradiation via reaction of radicals (O and OH) produced by direct photodissociation and

dissociative electron attachment (DEA) of the interfacial water molecules. The synthesized CO2

molecules can desorb in hot photon dominated regions (PDRs) and lost to space when ice coated

carbonaceous dust grains cycle within the protoplanetary disks. Thus, non-thermal formation of

CO2 at the buried ice:grain interface by VUV photons may regulate the carbon inventory during

the early stage of planet formation. This may help explain the carbon deficits in our solar system,

and suggests that a universal carbon deficit gradient may be expected within astrophysical bodies

surrounding center stars.

LABORATORY DETECTION OF HSNO FORMED BY THE SURFACE REACTION BETWEEN H2S AND NO

Marie-Aline Martin-Drumel1,*, Caroline C. Womack2, Kyle N. Crabtree3, Sven Thorwirth4 and Michael C. McCarthy1

1Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA2Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA

3Department of Chemistry, University of California-Davis, Davis, CA 95616, USA4I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany

*mmartin@cfa.harvard.edu

ABSTRACT

In the cold regions of the interstellar medium (ISM), many complex gas-phase molecules are believed to form on the surface of dust grains [1], although the exact mechanisms of dust-to-gas-phase chemistry remain subtle. In this regard, thionitrous acid, HSNO, may provide a sensitive test of dust grain chemistry. While calculations conclude that the gas phase reaction between the two well-known astronomical compounds H2S and NO [2-3] to yield HSNO is endothermic [4], much to our surprise we find that this molecule is efficiently formed in our experiment, presumably on metal surfaces, and then liberated into the gas-phase.

HSNO is a good candidate for detection in the ISM: it is a simple non-organic molecule composed of four elements which are relatively abundant in the ISM, it has a favorable partition function, and it has a modestly large permanent dipole moment of about 1 D. Determination of the HSNO abundance in space, relative to its more stable isomer HNSO, might provide a sensitive probe of solid-state versus gas-phase formation.

Here we report the first detection of both cis- and trans-HSNO, by means of Fourier-transform microwave spectroscopy and double resonance experiments. Subsequent isotopic studies have enabled a precise molecular structure determination of both species. Once formed, HSNO appears quite stable, as evidenced by its high steady-state concentration in our gas expansion. The global minimum structural isomer of the [H,N,S,O] system, cis-HNSO, is observed under the same experimental conditions, indicating some tendency towards rearrangement.

This talk will discuss the HSNO chemistry, the possible formation routes of this molecule, and more general NO-initiated processes.

REFERENCES[1] Bisschop S. E. et al. A&A 465, 913 (2007)

[2] P. Thaddeus et al., Astrophys. J. 176, L73 (1972)[3] H. S. Liszt & B. E. Turner, Astrophys. J. 224, L73 (1978)

[4] G. K. Kolluru et al., Redox Biology 1, 313 (2013)

INFRARED SPECTRA OF PROTONATED SPECIES AND THEIR NEUTRAL

COUNTERPARTS ISOLATED IN SOLID PARA-HYDROGEN

Masashi Tsuge,a) Yu-Jong Wu,b) Yuan-Pern Leea), c)

a) Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung

University, 1001, Ta-Hsueh Road, Hsinchu 30010, Taiwan b) National Synchrotron Radiation Research Center, 101, Hsin-Ann Road, Hsinchu 30076,

Taiwan c) Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan

FAX:+886-3-5713491/Tel:+886-3-5131459/e-mail:yplee@mail.nctu.edu.tw

Protonated polycyclic aromatic hydrocarbons (H+PAH) have been reported to have infrared

(IR) bands at wavenumbers near those of unidentified infrared (UIR) emission bands from

interstellar objects. However, recording IR spectra of H+PAH in laboratories is challenging. Two

spectral methods are employed to yield IR spectra of H+PAH. One employs IR multiphoton

dissociation (IRMPD) of H+PAH, but the bands are broad and red-shifted.1 Another measures the

single-photon IR photodissociation (IRPD) action spectrum of cold H+PAH tagged with a

weakly bound ligand, such as Ar, but application of this method to large PAH is difficult.2 A new

method for investigating IR spectra of H+PAH and their neutral counterparts was developed

using electron bombardment during p-H2 matrix deposition.

With this technique, we have recorded high-resolution IR absorption spectra of protonated

forms of benzene (C6H7+),3 naphthalene (1- and 2-C10H9

+),4 pyrene (1-C16H11+),5 to coronene (1-

C24H13+)6 and their neutrals. The significant superiority of the spectra recorded with our

technique to those with the Ar-tagging and IRMPD methods is demonstrated. A survey of these

experimental results shows that three major lines in the 79 m region are red-shifted from 7.19,

7.45, and 8.13 m of 1-C16H11+ to 7.37, 7.53, and 8.21 m of 1-C24H13

+, showing the direction

towards the UIR bands near 7.6, 7.8, and 8.6 m. In contrast, the line at 11.5 m of 1-C16H11+ is

blue-shifted to 11.4 m for 1-C24H13+, showing the direction toward the UIR band near 11.2 m.

We have also extended this work to ovalene, and the preliminary results indicate that the trend in

spectral shifts is maintained.

We have also investigated small protonated species such as HN2+, HN4

+, HCO2+, XeHXe+,

KrHKr+, and KrHXe+. In these cases, p-H2 compete for the proton and results into significant

matrix shifts in spectral bands. Some representative examples will be discussed.

REFERENCES

1. H. Knorke, J. Langer, J. Oomens, O. Dopfer, Astrophys. J. Lett. 706, L66 (2009).

2. A. M. Ricks, G. E. Douberly, M. A. Duncan, Astrophys. J. 702, 301 (2009).

3. M. Bahou, Y.-J. Wu, Y.-P. Lee, J. Chem. Phys. 136, 154304 (2012).

4. M. Bahou, Y.-J. Wu, Y.-P. Lee, Phys. Chem. Chem. Phys. 15, 1907 (2013).

5. M. Bahou, Y.-J. Wu and Y.-P. Lee, J. Phys. Chem. Lett. 4, 1989 (2013).

6. M. Bahou, Y.-J. Wu, and Y.-P. Lee, Angew. Chem. Int. Ed. 53, 1021 (2014).

LABORATORY STUDY AND ASTROPHYSICAL MODEL OF DUST SURFACE CHEMISTRY IN THE INNER SOLAR NEBULA

Martina D’Angelo1,2, Inga Kamp 2 & Petra Rudolf 11.Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The

Netherlands 2. Kapteyn Institute, University of Gronigen, PO Box 800, 9700 AV Groningen, The Netherlands

m.d.angelo@rug.nl

ABSTRACT

Recent observations have revealed a rich organic chemistry (e.g CO2, C2H2, HCN) in the inner warm regions of protoplanetary disks around young T Tauri stars1, posing the question to which extent the gas-grain interaction and the intense star radiation field (X-ray and UV) can favour the formation of essential organic molecules necessary for the origin of life.We are investigating the catalytic activity of montmorillonite clay, a natural crystalline aluminosilicate making up 40% of Earthʼs crust and likely representative of the phyllosilicate matrix of many meteorites2 and interplanetary dust particles3 (IDPs). Its layered, negatively charged structure promotes intercalation of polar molecules and formation of organo-silicate bonds 4. This smectite clay is an excellent water trap thanks to its swelling property5, suggesting that the clay matrix in meteorites may operate as water reservoir and could catalyze the formation of oligomers such as pre-RNA, giving new insights on how life originated on Earth6. In our project we combine a new astrophysical model of the Solar Nebula with laboratory surface experiments to unravel the mechanisms by which sub-micron-sized silicate dust grains could have contributed in developing simple organics, trapping and preserving them within their structure and transporting them throughout the Solar Nebula.We reproduce the physical conditions of the inner and warm region of a protoplanetary disk, where dust grain analogues are embedded in 0.01-0.1 mbar of H2/CO/N2 gas mixtures at 250-550 K temperature range, in accordance with the astrophysical disk model ProDiMo7. Typical surface science techniques such as Reflection-Absorption Infrared Spectroscopy (RAIRS) together with in situ X-ray Photoelectron Spectroscopy, developed at advanced synchrotron beamlines, are used to identify reactions products, binding mechanisms and sites. The empirical results will be used as input parameters for ProDiMo, to study the impact of catalytic surface reactions on the chemical composition of the inner Solar Nebula.

REFERENCES1. Carr J.S., Najita J.R., 2008, Science 319,504.2. Pearson, V. K. et al. Meteoritics & Planetary Science 2002, 37: 1829-1833.3. Hofmeister, A. M. and Bowey, J.E. Mon.Not.R. Astron.soc. 2006, 367: 577-591.4. Kaur, N. and Kishore, D. Journal of Chemical and Pharmaceutical Research 2012, 4: 991-1015.5. Schuttlefield, J.D., Cox, D., Grassian, V. H., Journal of Geophysical Research 2007, 112.6. Ferris, J.P., Phil.Trans. R. Soc. B 2006, 361: 1777-1786.7. Woitke, P., Kamp, I., Thi,W.F. 2009, A&A 501, 383.

Mechanisms of low-energy electron- induced processes in atomic

and molecular solids

Léon. Sanche*

Group in the Radiation Sciences, Department of Nuclear Medicine and Radiobiology,

Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, QC,

Canada J1H 5N4.

One possible pathway to the formation of the complex organic molecules observed in

astronomical data [1] involves the chemistry engendered by ionizing radiation fields (e.g.,

cosmic rays, X-rays and UV) in icy mantles surrounding the small, micron-sized dust

grains that exist in the interstellar medium (ISM) [2]. Since electrons with energies < 100

eV (i.e., low energy electrons: LEEs), are among the most numerous secondary species

generated by the interaction of ionizing radiation with matter [3], it is likely that

processes initiated by LEEs contribute significantly to the production (and destruction) of

molecular species in the icy mantles. The reactions of LEEs with molecular solids,

similar to those encountered in astrochemical ices, can be studied by irradiating with

energy selected beams of electrons, nanometer-scale molecular solid films constructed at

cryogenic temperatures. The basic mechanisms involved in these reactions are often

different than those of photons, and those found in the gas phase. As in the gas-

phase[4,5], electron-induced dissociation at energies < 20 eV, which can lead to further

radical reactions and thus the formation of new species, often occur via the formation of

transient negative ions (TNIs) [5]. Yet in addition to TNIs, other basic phenomena

specific to the condensed phase may occur; these include electron-exciton complex

formation and their coupling to TNIs and intermolecular trapping states, breakdown of

electron-molecule symmetry rules, cavity expulsion, cluster reactions, reactive scattering,

coupling of surface states to TNIs and strong density-of-state (DOS) effects on various

electron scattering cross sections [6]. These mechanisms will be explained at the

conference with specific results and a description of the techniques utilized to produce

them. It will be shown that reactions induced at cryogenic temperatures can be very hot

(i.e., they can occur at temperatures well over 10,000 K).

[1] The Cologne Database for Molecular Spectroscopy, HTTP:// http://www.astro.uni-

koeln.de/cdms/molecules

[2] A. G. G. M. Tielens, Rev. Mod. Phys., 85, 1021 (2013).

[3] S. M. Pimblott, and J. A. LaVerne, Radiat. Phys. Chem., 76 1244 (2007).

[4]. A. D. Bass and L. Sanche, Low Temp. Phys., 29, 202 (2003).

[5] C. R. Arumainayagam, H-L Lee, R. B. Nelson, D. R. Haines, R. P. Gunawardane,

Surf. Sci. Rep., 44 65 (2010)

[6] L. Sanche, Scanning Microscopy, 9619 (1995)

* Tel: 819-821-8000 ext. 74672; e-mail: leon.sanche@usherbrooke.ca

IMAGE CHARGE DETECTION MASS SPECTROMETRY: APPLICATIONS FROM ATOMS TO AEROSOLS

Joel Rivera, Katherine A. Nadler, Morgan Miller, Rico Otto and Robert E. Continetti

Department of Chemistry and Biochemistry, University of California, San Diego 9500 Gilman drive, La Jolla, CA 92093-0340

Tel: (858)-534-5559 email: rcontinetti@ucsd.edu

Image Charge Detection Mass Spectrometry (ICDMS) has become a powerful method for non-destructive mass and charge analysis of ionic species. When coupled with a linear electrostatic ion trap, the mass to charge ratio of an ionic species can be determined by measuring the induced charge of the ion as it oscillates in the linear electrostatic trap. The m/z of the ion can be determined from the oscillation frequency, while the charge of the ion is proportional to the induced charge measurement; the mass of the ion can be determined from these two measurements. Using the ICDMS technique, mass resolutions on the order of ∆m/m = 10-6 have been reported for atomic ions.1 Since charged particles are trapped using only electrostatic fields, ICDMS techniques are not mass limited and can be used for mass analysis of heavier particles. Measurements of intact viruses with masses on the order of 40MDa have been reported.2 We have built a Nanoparticle Electrostatic Trap (NET) that will be used for ICDMS studies of aerosol nanoparticles ejected from a quadrupole ion trap. The performance of this trap on systems ranging from atomic cations and anions to large (µm) diameter particles will be reviewed. In addition the interfacing of the NET with the quadrupole ion trap and a subsequent linear accelerator to allow hypervelocity impact studies of single particles will be discussed. Acknowledgements: The contributions of Joseph Taulane, Morgan Miller and Clayton Anderson as well as the support of the NSF MRI program under grant NSF-1229690 are acknowledged. 1. Zajfman D., Rudich Y., Sagi I., Strasser D., Savin D. W., Goldberg S., Rappaport M., Heber, O. Int. J. Mass Spec., 2003, 229, 55-60 2. Fürstenau S. D., Benner H. W., Thomas J. J., Brugidou C., Bothner B., Siuzdak G. Angew. Chem. Int. Ed. 2001, 40, 541-544

Thermal reactivity in interstellar ice

Patrice Theulé Laboratoire de Physique des Interactions Ioniques et Moléculaires

Aix-Marseille University, France Many reactions involving atoms, radicals, ions or neutrals are taking place in interstellar ice, increasing the molecular complexity in the interstellar medium. I will review a particular class of reactions: the purely thermal reactions involving neutrals. The small molecules, which are observed in the ice (H2CO, NH3, CO2, …) by infrared telescopes, can react to form larger molecules. The kinetics of these rations is dominated both by a large activation energy and by the diffusion of the reactants. The corresponding kinetics parameters (activation energy, diffusion coefficients) can be measured in laboratory and used in gas-grain models

Oxygen chemistry on dust grains

G. Vidali,1 J.He1,2

1Physics Department, Syracuse University, USA 2Current address: Chemistry Department, University of Hawai’i at Manoa, USA

(315) 443 3901 gvidali@syr.edu

ABSTRACT

Oxygen, the third most abundant element in space, intervenes in the formation of many molecular species, some of which are important in the generation of molecules relevant to the emergence of life. The realization that many gas-phase processes are insufficient to justify the abundance of some of these molecules has led to laboratory studies of the formation of molecules (such as H2O, CO2, and others) on the surface of dust grain analogs in simulated ISM conditions1,2. As these surface processes rely on the residence time and diffusion of reactants, we devised a combination of experiments and theoretical simulations to obtain desorption energy and energy barriers for diffusion of oxygen atoms and of important oxygen-containing molecules3. Here we present the results of recent experiments and simulations of the interaction of oxygen with surfaces of amorphous silicates, amorphous water ice (see figure below), and ammonia ice4,5. We also report on the formation of water on warm grains6, i.e., grains that are present at the edge of molecular clouds or of photodissociation regions, and on the formation of precursors of biogenic molecules5.

0 20 40 60 80 100 1200

2000

4000

6000

8000

QM

S s

ign

al (

cou

nts

/s)

Time (second)

temperature

32 amu

16 amu

48 amu30

40

50

60

70

Te

mp

era

ture

(K

)

This work is partially supported by NSF Astronomy & Astrophysics Grant No.1311958.

REFERENCES [1] G.Vidali, 2013, J. Low Temp. Phys., 170, 1. [2] T. Hama & N.Watanabe, 2013, Chem. Rev. 113, 8783. [3] J.He & G.Vidali:, 2014, Faraday Discuss. 168, 5. [4] J.He, J.Shi, T.Hopkins, G.Vidali & M.Kaufman, 2014, Astrophys. J., submitted. [5] J.He, G.Vidali, J.L.Lemaire, & R.Garrod, 2014, Astrophys. J., accepted. [6] J.He & G.Vidali, 2014, Astrophys.J. , 788, 50.

FORMATION OF LARGE ORGANIC MOLECULES ON COSMIC DUST GRAINS

(FROM PREBIOTIC TO AMINO ACIDS MOLECULES)

J. L. Lemaire

Paris Observatory (France)

jean-louis.lemaire@obspm.fr

ABSTRACT

Does life on earth come from interstellar space (IS)? This is a question of paramount interest

involving astrophysics and astrobiology. It has been recently demonstrated that part of the

terrestrial water is of IS origin [1]. This raises the question whether materials like amino-acids or

their pre-biotic molecular precursors could have been formed and brought to earth in the same

way than water. A related question is whether these molecules were formed in the gas phase or

through reactions at the surface or in the volume of ice-covered grains. This may have occurred

in the vicinity of proto-stellar cores in the first case, or, in the second one, deep into a pristine

dense molecular clouds at very low temperatures.

In any case, as far as bio-related molecules are concerned, chemistry with nitrogen-bearing

molecules (like NH3 and NO) is involved. I will review recent experimental work showing that

hydroxylamine (NH2OH) could be formed either by surface or by volume reactions in conditions

close to those prevailing in dense media. They use either electron-UV irradiation of water-

ammonia ices[2] or successive hydrogenation of solid nitric oxide[3] or the simple oxidation of

ammonia[4] or the reaction of ammonia with hydroxyl radicals in a rare gas matrix[5]. A step

further, the synthesis of the simplest amino-acids, glycine (NH2CH2COOH) and L- or D-alanine

(NH2CH3CHCOOH) has already been obtained via reactions in the gas phase involving

NH2OH+[6].

In addition to several earlier models demonstrating that the formation of all these molecules

is possible in the gas phase, a new recent three-phase gas-grain chemical kinetics model of hot

cores[7] shows that the results of ammonia oxidation obtained in [3] are plausible by

surface/volume reactions.

Although none of the aforementioned molecules (except glycine in a sample of cometary

origin) has been yet detected in the IS, they all are considered by many observers and modelers

as likely targets of detection with ALMA. A short review of the present observational status will

be presented and suggestions of conditions for future observations will be provided.

REFERENCES

[1] Cleeves L.I., Bergin E.A., C.M.O'D., Du F., Graninger D., Öberg K., Harries T.J. 2014, Science, 345,.1590

[2] Zheng W. & Kaiser R.I., J. Chem. Phys. A, 114, 5251, 2010

[3] Congiu E., Fedoseev G., Ioppolo S., Dulieu F., Chaabouni H., Baouche S., Lemaire J.L.,Laffon C., Parent Ph.,

Lamberts, T. Cuppen H.M., Linnartz H. ApJ Letters, 750, L12,.2012

[4] He J., Vidali G., Lemaire J.L., Garrod R.T. ApJ, 2015 (in press)

[5] Zins, E. L., & Krim, L. 2014 (in press) in 69th International Symposium on Molecular Spectroscopy

(http://isms.illinois.edu)

[6] Blagojevic V., Petrie S., Bohme D.K. Mon. Not. R. Astron. Soc., 339, L7, 2003 [7] Garrod, R.T. 2013, ApJ, 765, 60

Reactions of Hydrogen Atoms in Solid Parahydrogen: New Lessons to be Learned

Fredrick M. Mutunga, Morgan E. Balabanoff, David T. Anderson

Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071, USA

danderso@uwyo.edu

Our group has been studying a number of H-atom reactions in solid parahydrogen over the

temperature range between 1.7 and 4.3 K. The H-atoms are generated by the 193 nm in situ

photolysis of precursor molecules trapped in the parahydrogen crystal and the subsequent

reaction kinetics are followed using rapid scan FTIR spectroscopy. One of the unique properties

of H-atoms in solid parahydrogen is the H-atom diffusion rate is facile even at temperatures

below 2 K. The delocalized nature of H-atoms in solid parahydrogen therefore permits a variety

of H-atom reactions to be studied within the “deep-tunneling” regime. One of the first reactions

that we studied is the H+NO → HNO reaction which has been studied previously at low

temperature in solid parahydrogen [1] and in interstellar ice analogs [2]. This barrierless radical-

radical reaction proceeds at the diffusion limit over the full temperature range studied. However,

we also observe the competing H+NO → NOH reaction which is calculated [3] to have a

significant barrier (6200 K). Furthermore, we have studied the reactions of H-atoms with N2O,

HCOOH, and CH3OH and have measured somewhat surprising kinetics; all these reactions only

occur at an appreciable rate below a critical temperature of around 2.7 K. We have tried to

understand these kinetic results [4] using a two-step reaction mechanism that involves formation

of an encounter complex of the reactants followed by dissociation or reaction, but cannot

quantitatively model our results. In this talk, I will present results from our laboratory and

modeling studies that focus on the contrasting H-atom reaction kinetics measured for NO and

N2O.

References

[1]. M. Fushitani, T. Momose, “A Study on Diffusion of H Atoms in Solid Parahydrogen,” Low

Temp. Phys. 29, 740-743 (2003).

[2]. E. Congiu, et al., “NO Ice Hydrogenation: A Solid Pathway to NH2OH Formation in

Space,” Astrophys. J. 750, L12.1-4 (2012).

[3]. U. Bozkaya, J.M. Turney, Y. Yamaguchi, H.F. Schaefer III, “The Lowest-Lying Electronic

Singlet and Triplet Potential Energy Surfaces for the HNO–NOH System: Energetics,

Unimolecular Rate Constants, Tunneling and Kinetic Isotope Effects for the Isomerization

and Dissociation Reactions,” J. Chem. Phys. 136, 164303.1-15 (2012).

[4]. Fredrick M. Mutunga, Shelby E. Follett, David T. Anderson, “Communication: H-atom

reactivity as a function of temperature in solid parahydrogen: The H+N2O reaction,” J.

Chem. Phys. 139, 151104.1-4 (2013).

The Effects of Temperature on the VUV Photodesorption of CO2 Ice

Y.-J. Chen1, S.-R. Wu

1, G. M. Muñoz Caro

2, M. Nuevo

3,4, C.-C. Chu

1, T.-S. Yih

1,

W.-H. Ip5, and C.-Y. R. Wu

6

1 Department of Physics, National Central University, Jhongli City, Taoyuan County 32054,

Taiwan

2 Centro de Astrobiología, INTA-CSIC, Torrejón de Ardoz, 28850 Madrid, Spain

3 NASA Ames Research Center, Moffett Field, CA 94035, USA

4 BAER Institute, Petaluma, CA 94952, USA

5 Graduate Institute of Astronomy, National Central University, Jhongli City, Taoyuan County

32049, Taiwan

6 Space Sciences Center and Department of Physics and Astronomy, University of Southern

California, Los Angeles, CA 90089-1341, USA

+886-3-4227151 ext 65390/asperchen@phy.ncu.edu.tw

In this study, we present results from experiments in which CO2 ice was deposited and

VUV irradiated at different temperatures, in order to understand the effects of

temperature on the VUV photodesorption yield and to elucidate the mechanism of

VUV-induced photodesorption of CO2 ice. A quartz crystal microbalance (QCM) and

a Fourier-transform infrared (FTIR) spectrometer were used to measure the

photodesorption yield in two separated experimental vacuum systems, each equipped

with a quadrupole mass spectrometer (QMS) to characterize species desorbed during

the experiments.

The results from the QBM show that the photodesorption yield of CO2 ice deposited

and irradiated at 50 K and 70 K increases almost by an order of magnitude higher

with respect to the value at 14 K. The likely explanation is that photodesorption

occurs only on the top few monolayers of CO2 ice at 14 K, whereas CO and O2 can

desorbed from deeper monolayers of CO2 ice at temperatures above 30 K and 50 K,

respectively. On the other hand, mass spectra show that desorbed molecules mostly

originate after photodissociation of CO2 forming CO which photodesorbs, but also

photodesorption of C, O, CO2, and O2 was observed. The desorption rate of O2

increases rapidly when the deposition temperature of CO2 ice is above 50 K. In the

case of CO2 ice deposition and irradiation above 50 K, CO desorbs after the VUV

irradiation is stopped, the maximum mobile distance of CO and O2 molecules in CO2

ice was estimated at 50 K and 70 K.

A BROADBAND (0.3 – 7.5 THz) TERAHERTZ TIME-DOMAIN SPECTROMETER FOR THE STUDY OF ASTROPHYSICAL ICE ANALOGS

Brett A. McGuire1,2, Sergio Ioppolo3, Marco A. Allodi2, Xander de Vries4, P. Brandon Carroll2,

and Geoffrey A. Blake2,5 1National Radio Astronomy Observatory

2Division of Chemistry and Chemical Engineering, California Institute of Technology 3Department of Physical Sciences, The Open University

4Radboud University Nijmegen 5Division of Geological and Planetary Sciences, California Institute of Technology

bmcguire@caltech.edu // Office (626) 395-6791

We have previous reported at this meeting on the initial construction of a broadband (0.3 – 7.5 THz) TeraHertz time-domain spectrometer to study condensed-phase samples of astrophysically-relevant species. Despite the critical role these species play in interstellar chemical reactions and

evolution, and the wealth of observational facilities available or coming online in the THz, literature spectra for such species in this spectral window are discouragingly sparse. Here, we report on the continued design and construction of this spectrometer. Recent upgrades have

improved the sensitivity and resolution of the spectrometer by more than an order of magnitude. We will report on a number of the first studies enabled by these new capabilities, including

systematic studies of increasingly complex organic molecules, newly observed transitions of primary ice constituents (e.g., CO2), and polycyclic aromatic hydrocarbons. We find the spectra

to be extremely structure-dependent, and sensitive largely to long-range, large-amplitude motions within the ices. We will discuss the feasibility of the interstellar detection of species

from these spectra, approaches to the direct determination of optical constants, upcoming proof-of-concept observations with the SOFIA telescope, and the challenges associated with comparing

our spectra to theoretical calculations.

Formation of Dust under Astrophysical Conditions

Thomas Henning Max Planck Institute for Astronomy

Koenigstuhl 17, 69117 Heidelberg, Germany henning@mpia.de

The lecture will review our knowledge about stellar dust sources in space, ranging from AGB stars to supernovae. I will discuss the problem of efficient dust destruction and highlight the possibility of dust formation in the general interstellar medium. In the second part of my talk I will present the results of dedicated laboratory experiments to study dust formation under astrophysical conditions.

PRODUCTION OF OPEN-CHAIN PHOSPHANES AND ALKYL-PHOSPHINES IN

ASTROCHEMICAL ICE ANALOGUES

Andrew M. Turner, Matthew J. Abplanalp, Ralf I. Kaiser

Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii, United States

W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI

Email: aturner7@hawaii.edu, mja38@hawaii.edu, ralfk@hawaii.edu

ABSTRACT

The existence of phosphine (PH3) has recently been confirmed in the carbon-rich circumstellar

envelop of IRC +10216, which along with CP comprise the only phosphorus-containing

molecules discovered around this star. Methane (CH4) and acetylene (C2H2) were the first two

simple hydrocarbons detected around IRC +10216; furthermore, solid-state methane is known to

exist in the interstellar medium. We present results from the W. M. Keck Research Laboratory in

Astrochemistry that study the possible formation products of phosphine that enters the condensed

phase with methane. Phosphine and phosphine-methane ices were irradiated at 5.5 K in ultra-

high vacuum conditions to produce various larger phosphorus hydrides and alkyl-phosphines.

Reflectron time-of-flight mass spectrometry using 10.49 eV vacuum ultraviolet photoionization

proved to be the most sensitive detection method, capable of detecting compounds with greater

than nine phosphorus atoms. Infrared spectroscopy and quadrupole mass spectrometry were also

utilized, but these detected molecules with three phosphorus atoms or fewer. These tools

monitored the ices during temperature-programmed desorption from 5.5 to 300 K. The irradiated

ice analogues simulate the conditions of astrochemically relevant environments, enhance the

knowledge of phosphorus chemistry in the interstellar medium, and provide a list of possible

compounds that may be detected in circumstellar or interstellar media. Looking forward, these

products may be an intermediate to the formation of alkyl phosphonic acids, which were the only

phosphorus-containing organic molecules found in the Murchison meteorite.

Reflectron time-of-flight mass spectrum showing the sublimation products of phosphine

irradiation during warm-up from 5.5 to 300 K.

Methane ice photochemistry and kinetic study using laser desorption time-of-flight mass spectrometry at 20 K

Jean-Baptiste Bossa, Daniel Paardekooper, Karoliina Isokoski, and Harold Linnartz

Raymond and Beverly Sackler Laboratory for Astrophysics, Leiden Observatory, Leiden University, The Netherlands

Advances in telescope and interferometer arrays have highlighted a rich and exotic chemistryoccurring in the surroundings of star-forming regions, as evidenced by the detection of more than180 molecules and ions in space. Complex organic molecules (> 6 atoms) have beenunambiguously detected, but their formation mechanism and corresponding yields are stillunknown. Following astronomical observations, laboratory studies and models, it has become clearthat surface chemistry on icy grains steadily increases the chemical diversity and offers a way toexplain the molecular complexity in space. So far, systematic experimental investigations on theformation of complex organic molecules have been restricted, mainly due to the limitations imposedby standard solid-state techniques. To overcome these limitations, a new experimental setup as beendesigned.

A new ultra-high vacuum experiment is described that allows studying photo-induced chemicalprocesses in interstellar ice analogues. MATRIICES: a Mass Analytical Tool to study Reactions inInterstellar ICES applies a new concept by combining UV laser desorption and time-of-flight massspectrometry with the ultimate goal to characterize in situ and in real time the solid state evolutionof organic compounds upon VUV photolysis for astronomically relevant ice mixtures andtemperatures

The performance of the experimental setup is demonstrated by the kinetic analysis of the differentphotoproducts of pure methane (CH4) ice at 20 K. A quantitative approach provides molar fractionsat the different stages of the VUV irradiation. These data are then kinetically fitted to a reducedchemical reaction network in order to obtain the rate constants and ultimately the branching ratiosof photochemical reactions yielding new species with up to two carbon atoms (C2Hx and C3Hy).Convincing evidence is found for the formation of even larger species.

INTERSTELLAR AND OUTER SOLAR SYSTEM SOLIDS IN THE LABORATORY

E. Dartois 1,2

, I. Alata,3,1,2

, Karine Beroff 3, N. Bardin

4, R. Brunetto

1,2, Marin Chabot

5,6, B.

Crane1,2

, Gustavo A. Cruz-Diaz7, L. Delauche

4, P. Dumas

8, J. Duprat

4, C. Engrand

4, Lisseth

Gavilan1,2

, Aurelie Jallat5,6

, F. Jamme8, G. Morinaud

1,2, S. Mostefaoui

9, Guillermo M. Munoz

Caro7, T. Pino

3, E. Quirico

10, L. Remusat

9, Ch. Sandt

8, N. Szwec

1,2

1CNRS-INSU, Institut d'Astrophysique Spatiale, UMR 8617, 91405 Orsay, France 2Université Paris Sud, Institut d'Astrophysique Spatiale, UMR 8617, bât 121, 91405 Orsay, France

3Institut des Sciences Moléculaires d’Orsay (ISMO), UMR 8214-CNRS Université Paris Sud, bât.210, F-91405 Orsay Cedex, France 4 Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud, UMR 8609-CNRS/IN2P3, F-91405 Orsay, France

5 CNRS-IN2P3, Institut de Physique Nucléaire d’Orsay, UMR8608, 91406 Orsay, France 6 Université Paris Sud, Institut de Physique Nucléaire d’Orsay, UMR8608, IN2P3-CNRS, bât 103, 91406 Orsay, France

7 Centro de Astrobiologa (CSIC-INTA), Carretera de Ajalvir, km 4, Torrejon de Ardoz, 28850 Madrid, Spain 8Synchrotron SOLEIL, L’orme des Merisiers, BP 48, Saint Aubin, F-91192 Gif sur Yvette, France

9 Institut de Minéralogie, de Physique des Matériaux, et de Cosmochimie (IMPMC) - Sorbonne Universités - UMR 7590 CNRS, UPMC, IRD,

Muséum National d’Histoire Naturelle, 61 rue Buffon, F-75005 Paris, France 10UJF-Grenoble 1/CNRS-INSU, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG), UMR 5274, F-38041 Grenoble, France

EMAIL/emmanuel.dartois@ias.u-psud.fr

ABSTRACT

The interstellar medium is a physico-chemical laboratory where extreme conditions are

encountered, and whose environmental parameters (e.g. density, reactant nature, radiations,

temperature, time scales) define the composition of matter.

Whereas cosmochemists can spectroscopically examine collected extraterrestrial material in the

laboratory [e.g. 1,2,3,4,5], astrochemists must rely on remote observations to monitor and

analyze the physico-chemical composition of interstellar solids [e.g. 6,7,8,9,10].

The observations give essentially access to the molecular functionality of these solids, rarely to

elemental composition constraints and isotopic fractionation only in the gas phase. Astrochemists

bring additional information from the study of analogs produced in the laboratory, placed in

simulated space environments.

In this presentation, recent advances from laboratory experiments will be presented, setting

constraints on the composition of organic solids and molecules in the cycling of matter in the

Galaxy. One objective will be to draw some commonalities and differences between materials

found in the Solar System and Interstellar dust.

This talk will particularly focus on two carbonaceous dust materials, from the far (ISM) and near

(Solar System) space environments: (i) the small species released by the VUV irradiation of

interstellar a-CH analogues and their influence on PDR regions composition [11]; (ii)

extraterrestrial collected dust, Ultracarbonaceous Antarctic Micrometeorites (UCAMMs) from

the CONCORDIA collection [12], associated with the outer Solar System icy bodies.

REFERENCES

[1] Orthous-Daunay et al. (2013) Icarus 223, 534–543. [2] Brunetto et al. (2011) Icarus 212,

896–910. [3] Kebukawa et al. ( 2011) Geochim. Cosmochim. Acta 75, 3530–3541. [4] Sandford

et al. (2006) Science 314, 1720–1724. [5] Flynn et al. (2003) Geochim. Cosmochim. Acta 67,

4791–4806. [6] Spoon et al. (2007) The Astrophysical Journal 654, L49-L52 [7] Dartois &

Muñoz Caro (2007) Astronomy and Astrophysics 476, 1235-1242 [8] Van Diedenhoven et al.

(2004) The Astrophysical Journal 611, 928-939. [9] Chiar et al. (2002) The Astrophysical

Journal 570, 198-209. [10] Pendleton et al. (1994) The Astrophysical Journal 437, 683-696. [11]

Alata et al. (2014). [12] Dartois et al. (2013) 224, 243–252.

Laboratory studies of fundamental transient molecules containing 2nd-row elements

Sven Thorwirth1, Valerio Lattanzi2, Jürgen Gauss3, Ralf I. Kaiser4, Kyle N. Crabtree5, and Michael C. McCarthy6

1I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany 2Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, 85748 Garching, Germany

3Institut für Physikalische Chemie, Universität Mainz, 55099 Mainz, Germany 4Department of Chemistry, University of Hawai’i at Manoa, Honolulu, Hawaii 96822, United States

5Department of Chemistry, University of California - Davis, Davis, CA 95616, United States 6Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, United States

sthorwirth@ph1.uni-koeln.de / phone: +49-221-470-1936

ABSTRACT More than 175 astronomical molecules are now known, the vast majority detected by means of radio astronomy. Although those containing elements from the first row are most frequently observed in space, we are arguably entering the golden age of interstellar inorganic chemistry, because larger and more sensitive single-dish telescopes and interferometers have recently come on-line, and because of the availability of precise rest laboratory frequencies for many small molecules containing a second-row element or metal atom. Studies of these types of molecules in the gas phase are crucially important because they ultimately may provide key information on the formation and destruction of interstellar dust. In this regard, silicon-bearing molecules play a major role as gas-phase silicon monoxide, SiO, for example is thought to be created in the ISM from grains subjected to shocks [1]. In turn, grains may form in the same environment from condensation processes involving SiO [2]. In the laboratory astrochemistry group in Cambridge, a long-term program has been undertaken to systematically characterize new molecules that are derived from well-known and abundant astronomical ones, in which one or more atoms are replaced with their second-row counterpart. The pure rotational spectra of many such species have now been detected, including silanethione, H2SiS [3] (formally derived from H2CO), HPSi [4] (HCN/HNC), HCCNSi (HCCCN), SiH3SH (CH3OH), OSiS [5] (OCS/CO2) and HPCO/HNSiO [6] (HNCO). In nearly every instance, detection was accomplished by means of Fourier transform microwave spectroscopy guided by high-level quantum level calculations performed at the coupled-cluster level of theory. This talk will provide an overview of our recent work in this area, and a discussion of the prospects for future laboratory and radio astronomical studies.

REFERENCES [1] Schilke, Walmsley, Pineau des Forets, and Flower 1997, Astron. Astrophys. 321, 293 [2] Krasnokutski, Rouille, Jäger, Huisken, Zhukovska, and Henning 2014, Astrophys. J. 782, 15 [3] Thorwirth, Gauss, McCarthy, Shindo, and Thaddeus, Chem. Commun. 2008, 5292 [4] Lattanzi, Thorwirth, Halfen, Mück, Ziurys, Thaddeus, Gauss, and McCarthy 2010, Angew. Chem. Int. Ed. 49, 5661 [5] Thorwirth, Mück, Gauss, Tamassia, Lattanzi, and McCarthy 2011, J. Phys. Chem. Lett. 2, 1228 [6] Thorwirth, Lattanzi, and McCarthy 2014, submitted.

Polycyclic aromatic hydrocarbons as catalysts for interstellar chemical complexity

L. Hornekær

Dept. Physics and Astronomy, Aarhus University, Ny Munkegade Bygn. 1520, 8000 Aarhus C, Denmark

*liv@phys.au.dk

Even though Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous in the interstellar medium, the role they play as catalysts for interstellar chemistry is still not well understood. However, existing experimental data [1-3] and theoretical calculations [4] indicate that PAHs may well play a very active role, in particular in connection with the formation of molecular hydrogen. These findings may explain observations of increased molecular hydrogen formation rates in Photodissociation regions with high PAH abundances [5-6]. In my talk I will present temperature programmed desorption data demonstrating the formation of highly super-hydrogenated PAHs via hydrogen addition reactions and catalytic formation of molecular hydrogen via abstraction reactions at a wide range of H atom temperatures [1-3]. Approximate cross-sections for these reactions derived via model simulations will be presented [7]. The implications for the role played by PAHs in interstellar chemistry will be discussed. [1] J. D. Thrower, E. E. Friis, A. L. Skov, B. Jørgensen and L. Hornekær. Phys. Chem. Chem. Phys. 16, 3381 (2014) [2] J. D. Thrower, B. Jørgensen, E. E. Friis, S. Baouche, V. Menella, A. C. Luntz, M. Andersen, B. Hammer, and L. Hornekær. Astrophysical Journal 750, 1, (2012) [3] V. Menella, L. Hornekær, J. Thrower and M. Accolla. Astrophys. J. Lett. 745, L2 (2012) [4] E. Rauls and L. Hornekær. Astrophys. J. 679, 531 (2008) [5] E. Habart, F. Boulanger, L. Verstraete, G. P. des Fortes, E. Falgarone and A. Abergel, Astron. Astrophys. 397, 623 (2003) [6] E. Habart, F. Boulanger, L. Verstraete, C. M. Walmsley and G. P. des Forets, Astron. Astrophys. 414, 531 (2004) [7] A. L. Skov, J. D. Thrower and L. Hornekær. Faraday Discussions 168, 223 (2014)

A Mass-analytical Study of UV Irradiated Interstellar Ice

Daniel M. Paardekooper, Jean-Baptiste Bossa, Karoliina Isokoski and Harold Linnartz

Sackler Laboratory for Astrophysics, Leiden University, Leiden Observatory, the Netherlands

With ALMA surveying the inter- and circumstellar medium, it is expected that the number of

new molecules observed in space – more than 180 by now - will increase rapidly. This further

highlights the rich chemistry in star-forming regions. The underlying formation pathways,

however, are not well understood. Decades of astronomical observations, laboratory studies and

astrochemical models point towards a complex interplay between gas-phase and solid state

processes. Many of the larger species are expected to form on icy dust grains, following thermal

processing, irradiation by UV photons or X-rays or bombardment by atoms, electrons and

cosmic rays. In order to characterize these processes under fully controlled conditions, dedicated

laboratory experiments are needed.

Initially, complex ice mixtures were processed, quite often over long periods, and resulting

residues were investigated ex situ. The last decade ultra high vacuum techniques in combination

with RAIRS and/or TPD allow to study chemical processes in ices in situ. The two techniques,

however, are limited in their application; typically species with less than 10 atoms are studied.

Here we introduce MATRIICES [1], a new measurement concept that aims at studying the

formation pathways of larger species (>10 atoms) in photo-processed interstellar ice analogues,

by applying soft-laser ablation combined with time-of-flight mass spectrometry. Interstellar ice

analogues are first grown onto a cold gold substrate (20 K). Surface reactions are induced using

vacuum UV irradiation with a microwave powered H2-discharge lamp, producing Ly-α photons.

In the past CH3OH was already shown to be an excellent starting point for the formation of

complex molecules.[2] MATRIICES extends on this work.

In this talk, the performance of MATRIICES is discussed and data are presented for different

ices. Besides for methanol, also data for methane are presented. During UV irradiation, the

formation and destruction of different hydrocarbons is tracked. A quantitative approach provides

formation yields of several new species with up to four carbon atoms. Convincing evidence is

found for the formation of even larger species. [1,3]

References:

[1] D.M. Paardekooper, J.-B. Bossa, K. Isokoski, H. Linnartz, Laser desorption time-of-flight

mass spectrometry of ultraviolet photo-processed ices, 2014, Rev. Sci. Instrum. 85, 104501.

[2] K. I. Oberg, R. T. Garrod, E. F. van Dishoeck, H. Linnartz, Formation rates of complex

organics in UV irradiated CH3OH-rich ices I: Experiments, 2009, A&A 504, 891.

[3] D.M. Paardekooper, J.-B. Bossa, K. Isokoski, H. Linnartz, in preparation.

PHOTODETACHMENT STUDIES OF NEGATIVE IONS

D. Hanstorp

Department of Physics

University of Gothenburg

SE-412 96 Gothenburg, Sweden

dag.hanstorp@gu.se

ABSTRACT

The extra electron in a negative ion does not experience the Coulomb force from the nucleus at

large distances. Instead, core polarization induced by the extra electron stabilizes the ion. As a

consequence, the binding energies of negative are typically an order of magnitude smaller than

the ionization potential for neutral systems. Further, the number of excited states is very limited

and normally only the ground state is bound. Hence, traditional optical spectroscopy cannot be

used to investigate negative ions. However, recent interstellar observations of negative ions

have shown that bound-bound transitions can be used to detect negative ions. This has triggered

an intense search for negative ions in interstellar media as well as in corresponding laboratory

experiments.

I will review various laboratory experiments of negative ions. Optical photodetachment spectra

have been measured at the negative ion beam facility GUNILLA in Sweden, using infra-red,

visible and UV lasers. This has yielded information about electron affinities, fine structure

splittings and isotope shifts. Femtosecond spectroscopy has been performed using a velocity

map imaging spectrometer, and the first data from an angular resolved collinear electron

spectrometer will be reported. Further, the first experiment using the newly commissioned

cryogenic electrostatic double storage ring DESIREE, in which the life time of an excited state

in S- has been measured, will be presented. DESIREE is designed to study mutual neutralization

of negative and positive ions at conditions that resembles the environment in the interstellar

media.

A NEW LABORATORY FOR MM-WAVE CHARACTERIZATION OF COSMIC DUST ANALOGS

Thushara Perera

Illinois Wesleyan University tperera@iwu.edu

ABSTRACT

A custom experimental setup has been constructed for measuring the temperature-dependent

absorptivity of cosmic dust analogs, with the hope of providing input for millimeter-wave observations of dusty environments. A unique feature of this apparatus is that all of its

components—a 4-K cryostat, bolometer + optics, cold sample holder/exchanger, and Fourier transform spectrometer (FTS)—were designed specifically for laboratory studies of dust candidates. Some of the main concerns addressed by the instrumentation are: accurate

temperature control (between 5-50 K) of samples and ease of switching between samples, compactness of cold chamber as well as external FTS (using a novel FTS design), minimization

of optical windows in measurement scheme, use of mm-wave observational techniques to minimize optical and thermal systematics, and simplicity of operation (catered to undergraduate students) once completed. We have also started a dust synthesis effort locally, based on sol-gel methods. The measurement scheme as well as preliminary data on in-house and external (from

NASA Goddard) dust samples will be presented.

CHAIN ELONGATION REACTIONS OF CYANO IONS WITH HYDROCARBONS

P.Fathi,1 F. Lindén,1 D. Ascenzi2 and W. D. Geppert1 Physics Department, Roslagstullsbacken 21, S-10691 Stockholm, Sweden

Dept. of Physics, University of Trento, via Sommarive 14, I-38100 Trento, ITALY wgeppert@fysik.su.se

A multitude of large anions and cations has been detected in Titan’s ionosphere by the Cassini-Huygens mission [1,2], but their identity and their formation pathways are still elusive in many cases. However, ion-molecule-neutral reactions followed by dissociative recombination could be important routes to complex species. The ion–neutral mass spectrometer (INMS) has identified a number of ion masses corresponding to protonated nitriles and other nitrogen-containing ions [2]. In addition, the CN-, C3N

-, and C5N- anions have been detected by the electron plasma

spectrometer (EPS) on board the Cassini spacecraft. Thus, ions containing cyano groups can be expected to play a substantial role in the chemistry of Titan’s ionosphere. Reactions of these ions with unsaturated and saturated hydrocarbons could lead to larger ionic species, since such processes can be barrier-less and thus feasible at the temperatures prevailing in Titan’s ionosphere. Mutual neutralization reactions between cations and anions or dissociative recombination (in the case of cations) can then lead to heavy neutral molecules. However, quite a number of the detected cations possessing cyano groups are protonated nitriles, which are fairly unreactive and are mainly destroyed by dissociative recombination. Nevertheless, exceptions like the CH2CN+ ion exist. We investigated the reactions of the CH2CN+ ion with a multitude of saturated and unsaturated hydrocarbons (C2H2, C2H4, CH4 etc.) using the guided ion beam device at the university of Trento, Italy in order to determine the products and cross-sections of these processes and to establish if they are feasible pathways for building up entities with longer carbon and carbon nitrogen chains. Furthermore, the reactions of C3N

- with ethylene and acetylene have also been studied. Experiments using deuterated isotopologues as well as ab initio calculations on the MP2/6-311G++** level have been employed to explain the obtained findings.

REFERENCES [1] V. Vuitton, P. Lavvas, R.V. Yelle, M. Galand, A. Wellbrock, G.R. Lewis, A.J. Coates, J.-E. Wahlund, Planet. Space Sci. 57, 1558 (2009) [2] V. Vuitton, R. V. Yelle, M. J. McEwan, Icarus, 191, 722 (2007)

Understanding Interstellar Ices, from Molecular Structure to the Nano- Meso- and Micro- Scales

H.J. Fraser1, O. Auriacombe1, A. Dawes1, P. Elkind1, S. Gaertner1, C. Hill1, N. Pascual1, A. Suutarinen1, D. Chakarov2, J. Noble3, D. Bowron4, B. Ellison4, T. Youngs4, T. Loerting5

1Astronomy Division, Department of Physical Sciences, The Open University, Walton Hall, Milton

Keynes, MK7 6AA, + 44 1908 332 92, helen.fraser@open.ac.uk

2Chalmers University of Technology, Department of Applied Physics, Fysikgränd, 3, F5127 SE-412 96 Göteborg, Sweden, 3Laboratoire Physique des Interactions Ioniques et Moléculaires, UMR 633, Université de Provence CNRS, Centre St-Jérôme, 13397 Marseille Cedex 20, France, 4Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, Oxford, Didcot, OX11 0QX, UK, 5Institute of Physical Chemistry, University of Innsbruck, Innrain 52a, A – 6020 Innsbruck, Austria The precise structure of interstellar ices, Amorphous Solid Water (ASW) in particular, has long been debated, most importantly the issue of ice porosity1. If interstellar ice is porous this would inextricably link icy mantles with the earliest stages of planet building through grain aggregation2 and produce grain-surface areas up to three orders of magnitude greater than those currently utilised in gas-grain chemical models e.g.3. Porosity also greatly enhances the ability of the ice to uptake, then release (on heating) small gas adsorbates such as N2 CH4 or CO4. This property provides the strongest evidence that interstellar ices must be porous, accounting for the differences between predicted and observed gas-phase abundances e.g.5,6. Conversely, no dangling OH bond features have been reported in ice observations7, and a number of experiments conclude that interstellar ices must be non-porous, given that the ‘porosity measurables’, i.e. dangling OH bonds e.g.8, ice height9, and gas ad / desorption rates e.g.10, are all rapidly diminished as porous ASW is heated, exposed to electron, UV, or ion bombardment e.g.11,12, or subject to chemical reactions, especially H + H →H2

13 and H + OH →H2O14,15. Using the AKARI satellite we have been able to detect the complete interstellar water ice stretching vibration16, including the dangling-OH bond region. From observations of water ice on hundreds of lines of sight, we will show upper-limit detections of dangling OH spectra towards a handful of sources, proving that interstellar ices could have dangling OH bonds. However are the presence of dangling OH features and gas uptake reliable experimental measures of ice porosity? Recent neutron scattering data show that even compact ASW ices actually contain pseudo cylindrical pores of around 10 Å diameter17. We will show that the pore collapse process can only be initiated by energy input and is not autocatalytic18; such effects can be reproduced by molecular dynamics simulations of ASW ice-heating19. We can reconcile these new results with previous interpretations of TPD and RAIRS data, to understand ice porosity under interstellar conditions, and the effects of this on grain surface reactivity, ice growth20, and ice aggregation21-22. Looking forwards, this study highlights the need to move beyond “traditional” TPD and RAIRS surface science techniques to study solid-state ices of astronomical interest. I will finish this presentation by highlighting some new avenues of research being pursued in the Open University astrochemistry group, and new activities to more closely link the Physical Chemistry and Astronomy communities across Europe through the EU COST action CM1401 “Our Astrochemical History”. 1. Bartels-Rausch et al Rev Mod Phys (2012) 84 885 2.Wang et al ApJ (2005) 620 1027 3. Cazaux et al A&A (2010) 522 A74 4. Collings et al (2004) MNRAS 354 1123 5. Viti et al MNRAS (2004) 354 1141 6. Brinch et al A&A (2008) 489 617 7.Fraser et al MNRAS 353 59 (2004) 8. McCoustra & Williams MNRAS (1996) 279 L53 9. Bossa et al A&A (2012) 545 A82 10. May et al J Chem Phys (2013) 138 104501 11. Palumbo A&A (2006) 453 903 12. Raut et al J Chem Phys (2007) 126 244511 13. Accolla et al PCCP (2011) 13 8037 14. Oba et al ApJ (2009) 701 464 15. Accolla et al MNRAS (2013) 429 3200 16. Noble et al ApJ (2013) 775 85 17. Mitteldorfer et al PCCP 16 16013 (2014) 18. Collings et al AP&SS (2003) 285 633 19. Elkind et al JCP (2015) submitted 20. Pascal et al Nanotech (in prep) 21. Hill et al A&A (2015) 573 49 22. Hill et al A&A (2015) in press

Photoabsorption, Photodissociation, and Photodesorption of Astrophysical Ices G. M. Muñoz Caro1, R. Martín-Doménech1, J. Manzano Santamaría1, G. A. Cruz Diaz1, Y.-J. Chen2 1 Centro de Astrobiología, INTA-CSIC, Torrejón de Ardoz, 28850 Madrid, Spain 2 Department of Physics, National Central University, Jhongli City, Taoyuan County

32054, Taiwan The photodesorption of molecules, induced by VUV irradiation of interstellar and circumstellar ice analogs in the laboratory, has provided a plausible desorption mechanism in cold regions where thermal desorption is inhibited. The case of pure CO ice has been extensively studied because CO ice is not efficiently dissociated at photon energies below 11 eV, and therefore photodesorption becomes important. In addition, CO ice has a clear infrared absorption band that allows monitoring of the photodesorption. But most molecules present in ice mantles are, either efficiently photodissociated, or not active in the infrared. The study of photodesorption is therefore more challenging, and the detection of the desorbed molecules and their photoproducts is made directly in the gas phase. We use IR spectroscopy in transmittance of the ice and QMS of the desorbed molecules to provide a quantification of these processes. In addition, the VUV-photoabsorption of the molecular ice components is also measured, allowing the determination of their absorption cross sections. The final outcome is the estimation of the photodesorption rates as the number of photodesorbed molecules per absorbed photon in the ice. Our recent experimental results will be presented.

Photon Induced Desorption of interstellar relevant ices in the VUV

J.-H. Fillion(1,2), E.C. Fayolle(3), X. Michaut(1), L. Philippe(1), K. Öberg(3), H. Linnartz(4), C. Romanzin(5) and M. Bertin(1)

(1) Sorbonne Universités, UPMC Univ Paris 06, UMR 8112, LERMA, F-75005, Paris, France (2) LERMA, Observatoire de Paris, PSL Research University, CNRS, UMR 8112, F-75014, Paris, France

(3) Harvard-Smithsonian Center For Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA. (4) Sackler Laboratory for Astrophysics, Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300

RA Leiden, The Netherlands. (5) Laboratoire de Chimie Physique, CNRS UMR 8000, Univ Paris Sud, F-91400 Orsay, France.

ABSTRACT

During the cold and dense phase of star- and planet-formation, ices frozen out on microscopic interstellar dust

particles, are the dominant reservoir of molecules other than H2. When exposed to UV radiation from protostars,

background stars or through secondary H2 emission induced by cosmic rays, the mantle molecules non-thermally

desorb into the gas phase. Because of negligible thermal evaporation in these cold regions, this process is crucial to

explain the abundance of gas phase species below their accretion temperatures.

Previous estimates of the photodesorption rates have been largely based on broadband discharge lamps, peaking at

Ly-α wavelength (10.2 eV), which limits both the understanding of the desorption mechanisms and the applicability

to various astrophysical environments where UV field spectral profiles can be very different. In recent years, we

have developed a novel approach based on the coupling of the “Surface Processes and ICES” set-up to the DESIRS

beamline at SOLEIL, enabling tunable monochromatic excitation of interstellar ice analogs at low temperature (10

K). Instead of probing the depletion of the solid-state molecular concentration to obtain an average desorption rate,

the high photon fluxes provided by DESIRS has opened the opportunity to measure the wavelength dependency of

absolute desorption rates for individual particles ejected into the gas phase. This approach has led to revisit the

desorption mechanisms in the context of astrophysical media.

In this talk, previous results obtained on amorphous ice films of various composition (pure, and binary ices) and

various structures (mixed, layered) will be reviewed. The case of pure CO2 ices will be discussed considering the

chemical composition evolution of ice samples during the irradiation in conditions of laboratory experiments. The

role of indirect desorption induced by CO for the desorption of other organic compounds will be emphasis.

REFERENCES

1. M. P. Brown and K. Austin, The New Physique, Publisher City: Publisher Name, 2005, pp. 25-30. 2. M. P. Brown and K. Austin, Appl. Phys. Letters 85, 2503-2504 (2004). 1. E.C. Fayolle, M. Bertin, C. Romanzin, X. Michaut, K.I. Öberg, H. Linnartz, J.-H. Fillion, Astrophys. J. 739, L36 (2011) 2. M. Bertin, E.C. Fayolle C. Romanzin, , K.I. Öberg X. Michaut, A. Moudens, L. Philippe, P. Jeseck, H. Linnartz, J.-H. Fillion, Phys. Chem.

Chem. Phys. 14, 9929 (2012) 3. E.C. Fayolle, M. Bertin, C. Romanzin, H.A.M. Poderoso, L. Philippe, X. Michaut, P. Jeseck, H. Linnartz, K.I. Öberg, J.-H. Fillion, Astron.

Astrophys. 556, A122 (2013) 4. M. Bertin, E.C. Fayolle, C. Romanzin, H.A.M. Poderoso, X. Michaut, L. Philippe, P. Jeseck, K.I. Öberg, H. Linnartz & J.-H. Fillion,

Astrophys. J. under review (2013) 5. J.-H. Fillion, E.C. Fayolle, X. Michaut, M. Doronin, L. Philippe, J. Rakovsky, C. Romazin, N. Champion, K.I. Öberg, H. Linnartz and M.

Bertin, Faraday Discussions 168, 533 (2014)

THE ROLE OF GROUND STATE N(4S) NITROGEN ATOMS IN THE INTERSTELLAR

DUST GRAINS CHEMISTRY

Lahouari Krim

MONARIS , UMR 8233 du CNRS, de la MOlécule aux NAno-objets : Réactivité, Interactions et

Spectroscopies, Sorbonne Universités, Université Pierre et Marie Curie, UPMC Univ Paris 06, 4

place Jussieu, 75252 Paris cedex 05 France.

Fax 33 (0) 44 27 30 21 / Tel 33 (0)1 44 27 30 23 / Email: lahouari.krim@upmc.fr

Since the detection of the first chemical species in the interstellar media, it was found that a

complex chemistry takes place in this dilute and very cold medium. Using near IR spectroscopy, (a

region which is accessible to ground-based observations) laboratory experiments at very low

temperature and very low pressure under non-energetic conditions are of primary importance to

help understanding processes that may take place in some interstellar regions such as dense clouds.

Although the solid phase experiments are relevant from an astrochemical point of view, one is

unable to characterize all the byproducts formed for a studied reaction, due to the broad absorption

bands of the reactant ices. For this reason, some groups combine two complementary spectroscopy

methods to carry out their studies: infrared and mass spectroscopies. However the mass spectral

results, by warming the solid sample at relatively higher temperature, may be inappropriate to

characterize some reactions that should occur with no additional energy. This is the raison why we

have developed an original experimental approach that combine the study of heterogeneous

reactions (by exposing neutral molecules adsorbed on ice to non-energetic radicals H, OH, N...) and

a neon matrix isolation study at very low temperatures, which is of paramount importance to isolate

and characterize highly reactive reaction intermediates. Such experimental approach has already

provided answers1-4

to many questions raised about some astrochemically-relevant reactions

occurring in the ground state on the surface of dust grain ices in dense molecular clouds. The aim of

this new present work is to show the implication of ground state atomic nitrogen on hydrogen atom

abstraction reactions from some astrochemically-relevant species, at very low temperatures (3K-

20K), with no additional energy. Under cryogenic temperatures and with high barrier heights, such

reactions involving N(4S) nitrogen atoms should not occur spontaneously and require an initiating

energy. However, the detection of some radicals species as byproducts, in our solid samples left in

the dark for hours at 10K, proves that hydrogen abstraction reactions involving ground state N(4S)

nitrogen atoms may occur in solid phase at cryogenic temperatures. Our results show the efficiency

of radical species formation stemming from non-energetic N-atoms and astrochemically-relevant

molecules such as CH4, CH3OH and NH3. Such reactions, involving nitrogen atoms in their ground

states, may occur on the surface of dust grain ices in dense molecular clouds, could be the first key

step towards complex organic molecules production in the interstellar medium, and should be taken

into account in the astrochemical models.

Refrences (1) C. Pirim, L. Krim. Phys. Chem. Chem. Phys. 13, 19454 (2011), (2) P. Joshi, E. Zins, L. Krim Mon. Not. Roy. Astron. Soc. 419,

1713 (2012). (3) E. Zins, L. Krim RSC Advances. 4, 22172, (2014), (4) C. Pirim, L. Krim RSC Advances. 4, 15419, (2014).

1

Chemistry of ammonia ices under irradiation of energetic electrons

Marko Förstel, Pavlo Maksyutenko, Brant M. Jones and Ralf I. Kaiser

Department of Chemistry

W. M. Keck Research Laboratory in Astrochemistry

University of Hawaii at Manoa, Honolulu, Hawaii, HI, 96822, USA

Ammonia and/or ammonia hydride has been found in many places in our solar system; the atmospheres of

Jupiter, Saturn, Uranus and Neptune, on Kuiper belt objects and on comets[1-6]. Together with water,

carbon monoxide, carbon dioxide, methane and others, these solar system bodies possess a rich and

complex chemical environment which is constantly subject to ionizing radiation. We are aiming to fathom

the radiation induced chemistry in these systems and the study of their constituents is a necessary starting

point for the understanding of their multifaceted, heterogeneous chemistry.

Figure 1: Selected time programmed desorption profiles of ions detected in a time of flight mass spectrometer using soft x-ray

ionization at 10.5eV. Shown in blue are the traces of ice irradiated with 5keV electrons and in red the traces of the unirradiated

ice.

In this talk I report new experimental findings complimenting and extending an earlier infrared

absorption study on ammonia ice exposed to ionizing radiation[7]. Briefly, pure ammonia ice was

bombarded with 5keV electrons and the newly formed reaction products were then identified using

temperature program desorption coupled with soft photoionization reflectron time of flight mass

spectroscopy. With this very sensitive method we could not only clarify and confirm earlier tentative

assignments of molecules formed in the ice but also detect a new molecule - triazene. Triazene is a

potential high energy molecule which has not been isolated before[8].

References: [1] S.K. Atreya, P.R. Mahaffy, H.B. Niemann, M.H. Wong, T.C. Owen, Planetary and Space Science 51

(2003) 105.

[2] J.M. Bauer, T.L. Roush, T.R. Geballe, K.J. Meech, T.C. Owen, W.D. Vacca, J.T. Rayner, K.T.C. Jim,

Icarus 158 (2002) 178.

[3] J.M. Greenberg, C.E.P.M. Van de Bult, L.J. Allamandola, The Journal of Physical Chemistry 87

(1983) 4243.

[4] M.D. Hofstadter, D.O. Muhleman, Icarus 81 (1989) 396.

[5] G.F. Lindal, Astronomical Journal 103 (1992) 967.

[6] S. Maret, E.A. Bergin, C.J. Lada, Nature 442 (2006) 425.

[7] W. Zheng, D. Jewitt, Y. Osamura, R.I. Kaiser, The Astrophysical Journal 674 (2008) 1242.

[8] R.M. Richard, D.W. Ball, Journal of molecular modeling 14 (2008) 29.

The Role of Low-Energy (< 20 eV) Electrons in Astrochemistry

Katherine D Tran, Sebiha M Abdullahi, and Chris Arumainayagam Wellesley College,

Wellesley, MA 02481 In the interstellar medium, UV photolysis of ice mantles encasing dust grains is thought to be the mechanism that drives the synthesis of “complex” molecules. The source of this reaction-initiating UV light is assumed to be local because externally sourced UV radiation cannot penetrate the ice-containing dark, dense molecular clouds. Specifically, high-energy cosmic rays penetrate and ionize the molecular clouds, generating secondary electrons. Hydrogen molecules, present within these dense molecular clouds, are excited in collisions with these secondary electrons. The UV light emitted by these electronically excited hydrogen molecules is generally thought to photoprocess interstellar ice mantles to generate “complex” molecules. In addition to producing UV light, the large numbers of low-energy (< 20 eV) secondary electrons, produced by cosmic rays, can also directly initiate radiolysis reactions in the condensed phase. We hypothesize that cosmic-ray induced low-energy electron processing of interstellar ices may occur via three mechanisms:(1) the interaction of cosmic rays with gaseous molecular hydrogen producing low-energy electrons that can interact with the surface (top few molecular layers) of cosmic ices, (2) the interaction of cosmic rays with molecules within cosmic ices generating a cascade of low-energy electrons that can interact with the surface and the bulk of the ice mantles, (3) the interactions of the cosmic rays with the dust grain beneath the ice mantle engendering low-energy electrons that can interact with the bottom ice layers in contact with the dust grain. The goal of our studies is to understand the low-energy, electron-induced processes that occur when high-energy cosmic rays interact with interstellar ices. Using post-irradiation temperature-programmed desorption (TPD) and infrared reflection absorption spectroscopy (IRAS), we have investigated the radiolysis initiated by low-energy (5 – 20 eV) electrons in condensed methanol, ammonia, and water at ~ 90 K under ultrahigh vacuum (1×10−9 Torr) conditions. Our experimental results suggest that low-energy, electron-induced condensed phase reactions may contribute to the interstellar synthesis of “complex” molecules previously thought to form exclusively via UV photons.

Detection of Large Complex Organics via Reflectron Time-of-Flight Mass Spectroscopic Analysis of Methanol and Methanol:Carbon Monoxide Ices Exposed to Ionizing Radiation

Brant M. Jones, Surajit Maity, and Ralf Kaiser

University of Hawaii at Manoa

Department of Chemistry, W.M. Keck Research Laboratory in Astrochemisty,

Honolulu, HI 96822 I will present recent results regarding the formation of complex organics starting from simple methanol and mixed methanol – carbon monoxide ices upon interaction of these ice systems with ionizing radiation. Specifically, we have utilized reflection time-of-flight mass spectrometry (ReTOF) coupled with soft vacuum ultraviolet photoionization to observe high mass, complex organics as a function of their respective sublimation temperature. Surfaces of interstellar dust grains are enclosed with an icy shell consisting of simple carbon, hydrogen, oxygen, and nitrogen containing molecules. These micron sized dust grains have undergone millions of years of chemical processing due to ionizing radiation from galactic cosmic radiation and Lyman α photons from the interstellar UV field. Laboratory experiments have unequivocally shown that energetic processing of frozen gases by ionizing radiation will produce complex organics. These organics may then sublime for instance, via photodesorption, grain – grain collisions, shocking of the interstellar medium and/or direct thermal sublimation via hot cores. Our research has been focused on trying to understand how these ices have chemically and physically evolve by simulating the processing in an ultrahigh vacuum chamber coupled with in situ FTIR spectroscopy along with gas phase mass spectroscopy. Despite, numerous previous experimental investigations examining the effect of ionizing radiation on simple astrophysical ice analogues, our results suggest that there is still a vast unknown collection of molecules formed upon exposure of these ices to ionizing radiation. For example, recent results of the products synthesized from the energetic processing of simple amorphous methanol and methanol:carbon monoxide mixed ice systems indicate the possible formation of sugars with up to a five carbon chain backbone.

CONTRIBUTION OF QUANTUM CHEMICAL METHODS IN THE STUDY OF ICE-BASED COSMOCHEMISTRY

Albert Rimola

Departament de Química, Universitat Autònoma de Barcelona, 08193, Bellaterra, Catalonia, Spain

0034 93 5812173 / albert.rimola@uab.cat

ABSTRACT The existence of cosmic molecules is of great relevance due to their connection with the

chemical evolution steps occurring in the universe [1,2]. A key role of this chemical evolution is played by reactions occurring on or in cosmic ices. The current knowledge of the chemistry derived from these ices is mostly based on spectroscopic observations, helped by laboratory

experiments and astrochemical models. This combination has been fruitful to obtain important information, such as the chemical activity of an ice with a given composition [3]. However, this

approach cannot provide atomic-scale information such as the precise mechanistic steps and quantitative energetic data of the reactions, or the exact role played by the icy particles. This is a

serious limitation to fully understand the basic physical and chemical steps that lead to the chemical complexity in space. This information gap, however, can partly be filled in by using

theoretical calculations based on quantum mechanical approaches [4]. In this presentation, examples on how these theoretical calculations can contribute to ice-based cosmochemical

studies in both rationalizing puzzling experimental results as well as predicting possible reaction channels will be presented. In particular, results obtained from simulations devoted to the

formation of H2CO and CH3OH, both through H additions to CO on water ice nanoparticles and in the presence of an extra electron embedded in the water ice, will be shown [5]. Finally, the

fruitful interplay between theory and experiment will be demonstrated showing results focused on the formation of formaldehyde derivatives in water-dominated cometary ices [6,7].

REFERENCES [1] A.G.G.M. Tielens, Rev. Mod. Phys., 2013, 85, 1021.

[2] P. Caselli, C. Ceccarelli, A&AR, 2012, 20, 1. [3] T. Hama & N. Watanabe, , Chem. Rev., 2013, 113, 8783.

[4] S.T. Bromley, T.P.M. Goumans, E. Herbst, A.P. Jones & B. Slater, Phys. Chem. Chem. Phys., 2014, 16, 18623.

[5] A. Rimola, V. Taquet, P. Ugliengo, N. Balucani & C. Ceccarelli, submitted to A&A. [6] G. Danger, A. Rimola, N.A. Mrad, F. Duvernay, G. Roussin, P. Theule, T. Chiavassa, Phys.

Chem. Chem. Phys., 2014, 16, 3360. [7] F. Duvernay, G. Danger, P. Theule, T. Chiavassa, A. Rimola, ApJ, 2014, 791, 75.

Poster Presentations

Monday, February 23, 8:25 to 10:05 p.m.

P. Brandon Carroll

THz Spectroscopy of PAHs

Sebiha M Abdullahi

Revisiting Water Radiolysis

Jiao He

Formation of Hydroxyl amine on Dust Grains via

Ammonia Oxidation

Antonio Jimenez-Escobar

X-ray Irradiation of realistic H2O:CO ice mixtures.

Yuki Kimura

Molecular Formation Experiment by Catalytic

Reaction on Inorganic Surfaces at Low Pressure Environment

Léon Sanche

Cyanide and old Ice: Radiation Induced C-N Bond Coupling in Simulated Interstellar CO2/NH3 Ices

Niels Ligterink

Search for methylamine in high mass hot cores

Kazuya Osaka

Water Formation by Reaction of Solid Hydrogen

Peroxide with Hydrogen Atoms at Low Temperatures via Quantum Tunneling

Sergio Ioppolo

THz and Mid-IR Spectroscopy of Interstellar CO2 and CH3OH Ice

Christopher N. Shingledecker

Cosmic Ray Induced Interstellar Grain Chemistry: A “Big-Data” Approach

Tetsuya Hama

Controlling Hydrogenation of Solid Benzene by Quantum Tunneling via Surface Structure

THz Spectroscopy of PAHs P. Brandon Carroll, Marco A. Allodi, Sergio Ioppolo, Brett A. McGuire, & Geoffrey A. Blake

1200 E. California Blvd, Pasadena CA, 91125 (626) 395-6824/pcarroll@caltech.edu

Polycyclic aromatic hydrocarbons (PAHs) present themselves as a strong candidate as carriers of the unidentified infrared features (UIRs). As UIR carriers, PAHs may account for up to 20% of the interstellar carbon budget and may play key roles in many chemical and physical processes in the ISM, and yet our inability to definitively detect PAHs hinders our ability to evaluate the role they may play. A possible solution is observations in the TeraHertz (THz) regime, where observed transitions are specific to each molecule. Recent advances in THz technology have enabled both laboratory spectroscopy and astronomical observations in this region. A first step in both laboratory and astronomical studies of PAHs is the acquisition of spectra of pure PAH samples. Here, we present the THz time-domain spectra (0.3 - 7 THz) of several PAHs, including naphthalene, anthracene, and pyrene, and discuss the utility of these spectra for future laboratory and astronomical studies.

s

Revisiting Water Radiolysis

Sebiha M Abdullahi, Katherine D Tran, and Chris Arumainayagam Wellesley College,

Wellesley, MA 02481 The goal of our research is to obtain a fundamental understanding of water radiolysis, an

important topic that has been studied extensively since the discovery of natural radioactivity in 1896. Radiolysis of “dirty” water ice in the interstellar medium could have led to the synthesis of “complex” organic molecules which could be precursors for prebiotic molecules. To study the radiolysis of water, nanoscale-thin films of solid amorphous water are deposited on a Mo(110) single crystal substrate at 90 K in an ultrahigh vacuum (UHV) chamber. An electron gun is used to irradiate the thin films with low- and high- energy electrons ranging from ~5 to 1000 eV. Post-irradiation analysis of the species left behind in the film is done with temperature-programmed desorption (TPD) and infrared reflection absorption spectroscopy (IRAS). Because copious amounts of low-energy (< 20 eV) secondary electrons are produced when high-energy radiation interacts with condensed matter, our goal is to verify the hypothesis that it is these low-energy electrons that mediate high-energy condensed-phase water radiolysis.

Formation of Hydroxylamine on Dust Grains via Ammonia

Oxidation

Jiao He1*, Gianfranco Vidali1, Jean-Louis Lemaire2, and Robin T. Garrod3

1Physics Department, Syracuse University, Syracuse, NY 13244*Current Address: Department of Chemistry, University of Hawaii at Manoa, Honolulu,

HI 968222 Email: hejiaonju@gmail.com2Paris Observatory, Paris, France

3Center for Radiophysics and Space Research, Cornell University, Ithaca, NY 14853, USA

Hydroxylamine is considered to be a precursor to the formation of glycine, which isan important prebiotic molecule. Although not yet detected in the interstellar medium,the detection of hydroxylamine is likely with ALMA. Because of the ubiquity of NH3 andatomic oxygen in molecular clouds, the formation of hydroxylamine via ammonia oxidationseems plausible. We performed temperature programmed desorption (TPD) experimentsto study the formation of hydroxylamine. Ammonia and atomic oxygen were sequentiallydeposited onto an amorphous silicate surface when the surface was kept at 70 K. In the sub-sequent TPD, hydroxylamine (m/z=33) and its fragments were detected using a quadrupolemass spectrometer (QMS). Control experiments confirmed that hydroxylamine is formedby NH3+O instead of NH3+O2 or NH3+O3. The reaction efficiency was quantized by thedestruction rate of ammonia exposed to different doses of atomic oxygen, and the reac-tion NH3+O→NH2OH was found to be efficient. A simulation using a three phase densecloud model supports that the ammonia oxidation is an important formation mechanism forhydroxylamine.

This work is supported by the NSF Astronomy and Astrophysics Division (Grant No.1311958 to GV). We thankDr. J. Brucato of the Astrophysical Observatory of Arcetri (Italy) for providing the sample used in these experimentsand Zhirou Zhang, Jianming Shi, and Tyler Hopkins for technical help. RTG acknowledges the support of the NASAAstrophysics Theory Program (Grant No. NNX11AC38G).

REFERENCEHe, J., Vidali, G., Lemaire, J.L., and Garrod, R., ApJ accepted (2014)

X-ray Irradiation of realistic H2O:CO ice mixtures.

A. Jimenez-Escobar1, A. Ciaravella1, Y.-J. Chen2, C. Cecchi-Pestellini1,G. M. Muñoz-Caro3 1 INAf-Osservatorio Astronomico di Palermo, Palermo, Italy2 Department of Physics, National Central University, Jhongli City, Taiwan 3 Centro de Astrobiología (INTA-CSIC),Torrejón de Ardoz, Spain

ciaravella@astropa.uniap.it, jimenezea@astropa.unipa.it,cecchi-pestellini@astropa.unipa.it, asperchen@phy.ncu.edu.tw, munozcgster@gmail.com

ABSTRACT

H2O:CO ice mixtures were irradiated at 14 K with monochromatic soft X-rays of 300, 550, and900eV and with a broad spectrum (250 - 1200 eV). During irradiation, new products ofastrophysical interest were identified through its new infrared absorption bands such as CO2,HCO, H2CO, HCOOH, CH3OH. Carbon suboxides including C3O2, C3, C2O, and CO3 havebeen detected solely after irradiation with broad spectrum. During the subsequent warm-up of theirradiated samples, the infrared features of H2CO3 and O3 were detected. Monochromaticexperiment with 550 eV photons shows a larger H2O destruction, at the same absorbed Energy,displaying the role of the photon energy. The chemical network of the new species will bediscussed.

REFERENCES

MOLECULAR FORMATION EXPERIMENT BY CATALYTIC REACTION ON INORGANIC SURFACES AT LOW PRESSURE ENVIRONMENT

Yuki Kimura1, Naoki Watanabe1, Akira Tsuchiyama2, Hiroko Nagahara3, Akira Kouchi1

1Institute of Low Temperature Science, Hokkaido University, Sapporo, Hokkaido 060–0819, Japan

2Division of Earth and Planetary Sciences, Graduate School of Science, Kyoto University 3Department of Earth and Planetary Science, Graduate School of Science, The University of

Tokyo ykimura@lowtem.hokudai.ac.jp

ABSTRACT

At the transit stage from molecular cloud to primitive solar nebula, more complex molecules were produced from abundant H2, CO and N2 gases reacted mainly on the cooled surface of cosmic dust particles [1]. The complex molecules might be incorporated into the primordial organic system of the Earth and have some contribution on the evolution of life. Nanometer sized cosmic dust particles may work as catalysts to produce organic materials in the solar nebula after the formation of simple molecules in the molecular cloud. In the previous experimental study, organic molecules ranging from methane (CH4), ethane (C2H6), benzene (C6H6) and toluene (C7H8), to more complex species such as acetone (C3H6O), methyl amine (CH3NH2), acetonitrile (CH3CN) and N-methyl methylene imine (H3CNCH2) have been produced using such as the Fischer-Tropsch type (FTT) and Haber-Bosch type (HBT) reactions on analogs of naturally occurring grain surfaces at higher-temperature (>573 K) and pressure (~1 atm) than the expected conditions in the solar nebula [2-6]. In this project, we have performed molecular formation experiments in a more plausible environment [lower temperature (100-500 K) and pressure (10-3-100 Pa)]. We are constructing a vacuum chamber based on a new concept to conduct the experiments mentioned above. The chamber with a differential pumping system has a temperature-controlled substrate, a Fourier transform infrared spectrometer (FT-IR), and two quadrupole mass spectrometers (Q-MSs). FT-IR measures the vibration modes of adsorbed and produced molecules on the surface and the Q-MSs detect volatile molecules, respectively. As a preliminary experiment, the substrate has a gold thin film was used in a continuous gas flow of a mixture gas of H2 and CO for FTT reactions to check the background. Then, the gold thin film is replaced by magnesium silicate thin film. Resulting reaction rates of molecules on the substrates will be shown as a function of temperature and pressure in the workshop.

REFERENCES [1] J. Llorca and I. Casanova, Meteorit. Planet. Sci. 35, 841 (2000). [2] H. G. G. M. Hill, and J. A. Nuth, Astrobiology 3, 291 (2003). [3] J. A. Nuth, N. M. Johnson, and S. Manning, The Astrophysical Journal 673, L225 (2008). [4] J. A. Nuth, N. M. Johnson, and S. Manning, Organic matter in space, Proc. IAU Symp. 251,

edited by S. Kwok and S. Sandford, Cambridge Univ. Press, NY (2008), pp. 403–408. [5] J. A. Nuth, Y. Kimura, C. Lucas, F. Ferguson, and N. M. Johnson, The Astrophysical Journal

Letters 710, 98 (2010). [6] Y. Kimura, J. A. Nuth, N. M. Johnson, K. D. Farmer, K. P. Roberts, and S. R. Hussaini,

Nanoscience and Nanotechnology Letters 3, 4 (2011)

Cyanide and old ice: radiation induced C-N bond coupling in simulated interstellar CO2/NH3 ices

S. Esmaili, A.D. Bass, P. Cloutier, L. Sanche, and M. A. Huels Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences,

University of Sherbrooke, Sherbrooke, QC, Canada J1H 5N4

More than 180 molecules, many of them organic or biotic, have been observed within interstellar media (ISM). Experimental and observational evidence supports the notion that much of this intriguing molecular diversity arises from heterogeneous chemistry occurring on icy surfaces of ISM dust grains [1]. These ices are exposed to ionizing radiation including UV, x-ray and cosmic radiation fields, and secondary electrons with initial energies less than 100 eV are abundantly produced along ionizing radiation tracks. Thus, one approach to investigate the chemistry occurring in these ices is to irradiate nanometer thick molecular solids of simple molecular constituents, with energy selected electron beams, and to monitor the electron stimulated desorption of new molecular product ions [2]. Of particular interest is the formation of HCN, which is a tracer of dense gases in interstellar clouds, and is ubiquitous in the ISM. Moreover, the study of the formation and subsequent radiation chemistry of HCN fragments such as CN- is essential to the understanding of the basic building blocks of life such as amino acids [3, 4] or purine bases of DNA, e.g. adenine, which consist essentially of HCN subunits. Here we present measurements of 70 eV electron irradiation of multilayer films of CO2, NH3 and CO2/NH3 mixtures (1:1) on Pt(111). The electron stimulated desorption (ESD) yields of cations and anions are recorded as a function of electron fluence. Measurements at very low fluence show the prompt desorption of cationic reaction/scattering products, e.g. C2

+,C2O2+, C2O+, CO3

+, C2O3+ or

CO4+ from pure CO2, and NH4

+, N2+, N2H+ from pure NH3, and NO+, NOH+ from CO2/NH3

mixtures. Most saliently, increasing signals of negative ion products desorbing during prolonged irradiation of CO2/NH3 films included C2

, C2H, C2H2, as well as CN, HCN and H2CN. The

gradual appearance of the desorption signals of the latter three anions during continuing irradiation, suggests that these fragments result from the dissociation of much larger molecules that contain new nitrile groups, and which form during electron irradiation of these simulated interstellar surface ices. In our experiments, the identification of particular product ions was accomplished by using 13CO2 and 15NH3 isotopes (This work has been funded by NSERC).

REFERENCES [1] N. J. Mason, A. Dawes, P. D. Holtom, R. J. Mukerji, M. P. Davis, B. Sivaraman, R. I. Kaiser, S. V. Hoffmann, and D. A. Shaw, Faraday Discuss. 133, 311 (2006). [2] M. A. Huels, L. Parenteau, A. D. Bass, and L. Sanche, International Journal of Mass Spectrometry 277, 256 (2008). [3] M. H. Vera, Y. Kalugina, O. Denis-Alpizar, T. Stoecklin, and F. Lique, J. Chem. Phys. 140 (2014). [4] J. Loison, V. Wakelam, and K. M. Hickson, Monthly Notices of the Royal Astronomical Society 443, 398 (2014).

Search for methylamine in high mass hot cores  

Niels Ligterink1,2, Ewine van Dishoeck1,3 1Leiden Observatory, Leiden University, 2Raymond and Beverly Sackler Laboratory for Astrophysics, Leiden Observatory, 

Leiden University, 3Max­Planck Institut für Extraterrestrische Physik (MPE), Garching  

 Methylamine is potentially an important tracer for the importance of UV radiation in inducing chemistry in ice mantles on                                     

interstellar dust grains. The formation of methylamine is thought to follow from the addition of the CH3 and NH2 radical [Garrod                                         et al. 2008], which in turn are formed by UV photodissociation of methane and ammonia. Subsequent heating of the ice mantles                                         as the dust grains move inwards to the protostar causes the radicals to become mobile and react with each other. Further                                         heating results in the release of the newly formed methylamine to the gas phase, from where its rotational spectrum can be                                         detected by telescopes on Earth and in space.  

A particularly interesting molecule to compare with methylamine is formamide, NH2CHO. Whereas methylamine has so far only                                 been detected toward the galactic center [Belloche et al. 2013 e.g.], formamide is more widely observed [Halfen et al. 2011,                                       Bisschop et al. 2007 e.g.] and is in fact the most observed amine containing molecule. Contrary to the proposed radical­radical                                       interaction that forms methylamine, formamide can be formed by H and N atom addition to CO or H atom addition to HNCO                                           (isocyanic acid).  In this poster deep JCMT searches for a number of methylamine transitions toward nine high mass hot cores are presented                                       [Ligterink et al. submitted]. This did not result in clear methylamine detections, however it was possible to determine upper limits                                       of CH3NH2. Comparisons are made with results from Bisschop et al. 2007 and Isokoski et al. 2013, whose data were taken                                         towards the same sources using the same telescope making a direct comparison possible. Abundance ratios of methylamine                                 over formamide, methanol and acetonitril are obtained and compared with model values of Garrod et al. 2008, which show that                                       methylamine is overproduced in these models. Further conclusions are drawn about methylamines origin, its potential as UV                                 tracer and the nitrogen chemistry in the studied hot cores.   R.T. Garrod, S.L. Widicus Weaver, E. Herbst, 2008, APJ 682:283­302 A. Belloche, H.S.P. Müller, K.M. Menten et al. 2013, A&A 559, A47 D. T. Halfen, V. Ilyushin and L. M. Ziurys, 2011, APJ 743:60 S.E. Bisschop, J. K. Jørgensen, E. F. van Dishoeck et al. 2007, A&A 465, 913­929 N.F.W. Ligterink, E.D. Tenenbaum and E.F. van Dishoeck, A&A, submitted K. Isokoski, S. Bottinelli, E.F. van Dishoeck, 2013, A&A 554, A100  Contact or more information: ligterink@strw.leidenuniv.nl     

Water Formation by Reaction of Solid Hydrogen Peroxide with Hydrogen Atoms at Low

Temperatures via Quantum Tunneling

K. Osaka1, Y. Oba1, A. Kouchi1, and N. Watanabe1

1Institute of Low Temperature Science, Hokkaido University, Japan

+81-11-706-5477/k_osaka@lowtem.hokudai.ac.jp

ABSTRACT

Water (H2O) is one of the most important constituents of icy grain mantles in molecular clouds.

The observed abundance of water molecules cannot be explained only by the gas phase synthesis,

and thus surface reactions on cold interstellar grains must play an important role. H2O formation

has been proposed to originate from hydrogenation of atomic oxygen (O), molecular oxygen (O2),

or ozone (O3), and is completed by the following reactions [1,2]:

OH + H → H2O, (1)

OH + H2 → H2O + H, (2)

H2O2 + H → H2O + OH. (3)

Among these reactions, the experimental study of reaction (3) is associated with difficulty in

producing pure solid H2O2 and therefore has remained to be done. Here we report experimental

results on the formation of H2O via reaction (3) and its isotope effect using high-purity (>95%)

solid H2O2 and D2O2.

Experiments were performed using the Apparatus for SUrface Reations in Astrophysics

(ASURA), which mainly consists of a main chamber, and an atomic source chamber. Pure solid

H2O2 (D2O2) was prepared by the codeposition of H atoms with O2 molecules on a substrate at

45-50 K and then exposed to cold H (D) atoms (100 K) at 10-30 K. The reaction products were

measured by FT-IR in situ.

We found that the H2O2 solid reacts with both H and D atoms at 10–30 K despite the large

activation barriers (~2000 K) [3] and also that the rate of reaction with H atoms is approximately

45 times faster than that with D atoms at 15 K. This isotope effect suggests that these reactions

occur through quantum tunneling. We will further discuss the astrophysical implications of this

work in the poster.

REFERENCES

[1] A. Tielens and W. Hagen, Astron. Astrophys., 1982, 114, 245–260

[2] H. M. Cuppen and E. Herbst, Astrophys. J., 2007, 668, 294–309

[3] R. Atkinson et al., Atmos. Chem. Phys., 2004, 4, 1461–1738

THz AND MID-IR SPECTROSCOPY OF INTERSTELLAR CO2 AND CH3OH ICE

S. Ioppolo1, X. de Vries

2, B. A. McGuire

3, M. A. Allodi

3, P. B. Carroll

3, G. A. Blake

3, 4

1 Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK

2 Institute for Molecules and Materials, Radboud University Nijmegen, Nijmegen NL6500 GL, NL

3 Division of Chemistry and Chemical Engineering, Caltech, 1200 E California Blvd., Pasadena, USA

4 Division of Geological and Planetary Science, Caltech, 1200 E California Blvd., Pasadena, USA

Fax: +1-(626)-5851917 / Tel: +1-(626)-3956296 / Email: gab@gps.caltech.edu

Astrochemistry is currently being driven forward by an impressive amount of high quality

observational data from astronomical facilities in the far-infrared (far-IR), submillimeter, or

terahertz (THz) frequency range. The Herschel archive as well as data from SOFIA and ALMA

provide valuable information on the rotational motions of small molecules, the rovibrational

transitions of larger species, interlayer vibrational and single molecule torsional modes of ices,

and phonon modes in solids. Moreover, due to the long-range nature of the forces involved in the

THz modes of solids, these data potentially contain information on the structure, composition,

and thermal processing history of interstellar dust and ice [1, 2]. Therefore, spectroscopy in the

THz region of the electromagnetic spectrum holds the key to our ability to understand the

physics and chemistry of the interstellar medium. Ices, however, have typically only been

observed under specific conditions via mid-IR absorption spectroscopy toward the line of sight

to bright sources (i.e., field stars or protostars). THz spectroscopy provides the unique

opportunity to detect ices in disks and clouds in either emission or absorption against the dust

continuum, through a number of distinct features and, theoretically, along any line of sight. To

take full advantage of the enormous amount of available observations, laboratory analogs must

be studied systematically. After water ice [3], carbon dioxide (CO2) and methanol (CH3OH) are

the best candidates to be observed at THz frequencies, because of their abundance relative to

water and their clear and distinct THz features in the solid phase [2, 4].

My poster will review the latest laboratory results on THz Time-Domain spectroscopy of

CO2 and CH3OH ices as obtained by the Blake Research Group at Caltech. The THz TD

spectrometer that my co-workers and I have constructed and optimized relies upon an ultrafast

laser system to generate and detect THz pulses in the range between 0.3 - 7.5 THz (10 - 250 cm-1

or 1000 - 40 µm). The system is coupled to a FT-IR spectrometer to monitor the ices in the mid-

IR (4000 - 500 cm-1

or 2.5 - 20 µm). Laboratory results are supported by theoretical calculations

to retrieve fundamental information on the nature of the phonon vibrational modes observed in

our THz spectra.

REFERENCES

[1] Allodi, Ioppolo, Kelley, McGuire, Blake 2014, PCCP, 16, 3442. [2] Ioppolo, McGuire,

Allodi, Blake 2014, FD 168, 461. [3] McClure, Manoj, Calvet, Adame, Espaillat, Watson,

Sargent, Forrest, D’Alessio 2012, ApJL, 759, 10. [4] General Discussion 2014, FD 168, 423.

Cosmic-Ray Induced Interstellar Grain Chemistry: A “Big-Data”

Approach

Christopher N. Shingledecker and Eric Herbst

Department of Chemistry, University of VirginiaCharlottesville, VA 22904

email: cns7ae@Virginia.EDU

Abstract

A lingering problem in the field of astrochemistry is how to treat the interaction between cosmic radiation,which consists mostly of high-energy protons, and interstellar dust grains. The ices that cover these dustgrains are the engine that drives much of the complex chemistry observed in these regions. Much of thedifficulty in incorporating collisions between cosmic rays and dust grains into existing astrochemical modelsis due to the number of possible physical processes that can occur, such as the desorption of energized speciesand a cascade of up to 104 secondary electrons produced in collisions between the ion and bulk [4]. Theseelectrons have energies of less than 50 eV [2] and can, in turn, interact with the surrounding molecules viaa variety of mechanisms, many of which lead to molecular dissociation [1].

Our initial approach to this problem is to extend current methods for simulating grain chemistry byreducing the complexity of the physics through reasonable approximations. The basis for the grain chemistryis the kinetic Monte Carlo model described in Chang and Herbst [3]. There, the ice is represented as a threedimensional matrix comprised of normal crystal lattice sites and interstitial sites which can be thought of aspotential locations for inclusions within the structure. Cosmic-ray collisions are treated stochastically. Theirtracks within the matrix are calculated and interactions can occur when the track crosses an occupied site.Electrons produced in ionization events are placed at a random, nearby site and react immediately with aneighboring species. Ionic species thus produced are made to recombine. Finally, in order to overcome thelimits of running this simulation on a single processor, the program will be run on a large multiprocessortype supercomputer. This will be accomplished by dividing the total grain surface into a large number ofdiscrete units, each running on one node of a supercomputer.

References

[1] C. R. Arumainayagam, H.-L. Lee, R. B. Nelson, D. R. Haines, and R. P. Gunawardane. Low-energyelectron-induced reactions in condensed matter. Surface Science Reports, 65(1):1–44, Jan. 2010.

[2] E. M. Bringa and R. E. Johnson. A new model for cosmic-ray ion erosion of volatiles from grains in theinterstellar medium. The Astrophysical Journal, 603(1):159, 2004.

[3] Q. Chang and E. Herbst. Interstellar simulations using a unified microscopic-macroscopic monte carlomodel with a full gas-grain network including bulk diffusion in ice mantles. The Astrophysical Journal,787(2):135, June 2014.

[4] N. J. Mason, B. Nair, S. Jheeta, and E. Szymaska. FD 168: Electron induced chemistry a new frontierin astrochemistry. Faraday Discussions, 2014.

1

Controlling Hydrogenation of Solid Benzene by Quantum Tunneling via Surface Structure

Tetsuya Hama,† Hirokazu Ueta,

† Akira Kouchi,

† Naoki Watanabe,

† and Hiroto Tachikawa

‡

†Institute of Low Temperature Science, Hokkaido University

‡Division of Materials Chemistry, Graduate School of Engineering, Hokkaido University

hama@lowtem.hokudai.ac.jp

Polycyclic aromatic hydrocarbons (PAHs) and mixed aromatic/aliphatic carbonaceous dusts are

abundant in the interstellar medium. Benzene (C6H6), the building block of PAHs, has also been

detected in circumstellar environments such as post-asymptotic giant branch objects. C6H6 can

be produced in cold interstellar clouds, typically at 10 K via gas-phase reactions, in which the

calculated abundance was < 10−9

with respect to H2.1 Surface reactions with H atoms are some of

the most important chemical processes for these materials.2 However, activation barriers of about

20 kJ mol-1

exist for hydrogenation of aromatic hydrocarbons in order to break the aromaticity.

Here, we show that H atoms can efficiently add to C6H6 molecules on the surface of amorphous

C6H6 solid at 10–50 K by quantum tunneling to form cyclohexane (C6H12).

C6H6 + H → C6H7, Ea = 18.2 kJ mol−1

, (1) C6H7 + H → C6H8, (2)

C6H8 + H → C6H9, Ea = 6.3 kJ mol−1

, (3) C6H9 + H → C6H10, (4)

C6H10 + H → C6H11, Ea = 10.5 kJ mol−1

, (5) C6H11 + H → C6H12, (6)

Ea represents the activation barrier in the gas phase. In situ infrared spectroscopy revealed that

cold H atoms can add to the amorphous C6H6 surface at 10–50 K to form C6H12 by tunneling.

The present study suggests that cyclic alkenes and alkanes, such as C6H10 and C6H12, can be

formed on the surface of dust grains in interstellar clouds following subsequent H atom addition

to aromatic molecules (e.g., C6H6) once the surface temperature reaches at 10–50 K. We also

infer that it can efficiently occur in the outer disk in protoplanetary disks, where the temperature

drops below 50 K.

We also found that the surface structure

strongly controls the hydrogenation

efficiency; hydrogenation is greatly

reduced on crystalline C6H6 (Figure). We

suggest that the origin of the high

selectivity of this reaction is the large

difference in geometric constraints

between the amorphous and the

crystalline surfaces. The present findings

can improve our understanding of

heterogeneous reaction systems,

especially those involving tunneling.3

REFERENCES

1. Jones et al., PNAS. 2011, 108, 452–457.

2. Skov et al., Faraday Discuss. 2014, 168, 223–234.

3. Hama et al., J. Phys. Chem. Lett. 2014, 5, 3843−3848.

Figure. Schematic illustration of the present study.

List of Participants

Last Name First Name Affiliation

Abdullahi Sebiha Wellesley College

Abplanalp Matthew University of Hawaii at Manoa

Ahmed Musahid Lawrence Berkeley National Laboratory

Anderson David University of Wyoming

Boogert Adwin USRA/SOFIA, NASA Ames

Bossa Jean-Baptiste Leiden University

Brumer Paul University of Toronto

Carroll Brandon California Institute of Technology

Chen Yu-Jung National Central University

Cheng Bing-Ming National Synchrotron Radiation Research Center

Continetti Robert University of California at San Diego

Crandall Parker University of Hawaii at Manoa

D'Angelo Martina University of Groningen

Dartois Emmanuel Institut d'Astrophysique Spatiale

de Marcellus Pierre Institut d'Astrophysique Spatiale

Ehrenfreund Pascale George Washington University

Fillion Jean-Hugues Pierre and Marie Curie University

Förstel Marko University of Hawaii at Manoa

Fraser Helen The Open University

Gavilan Lisseth Institut d'Astrophysique Spatiale

Geppert Wolf Stockholm University

Gorczyca Thomas Western Michigan University

Gordon Karl Space Telescope Science Institute

Gudipati Murthy Jet Propulsion Laboratory

Hama Tetsuya Institute of Low Temperature Science, Hokkaido University

Hanstorp Dag University of Gothenburg

He Jiao University of Hawaii at Manoa

Henning Thomas Max Planck Institute for Astronomy

Hornekær Liv Aarhus University

Hudson Reggie NASA Goddard Space Flight Center

Ioppolo Sergio The Open University

Jimenez-Escobar Antonio Osservatorio Astronomico di Palermo (INAF-OAPa)

Jones Brant University of Hawaii at Manoa

Kaiser Ralf University of Hawaii at Manoa

Kimura Yuki Institute of Low Temperature Science, Hokkaido University

KRIM Lahouari Pierre and Marie Curie University

Le Sergeant d'Hendecourt Louis IAS-CNRS-FRANCE

Lee Yuan-Pern National Chiao Yung University

Lemaire Jean Louis Observatoire de PARIS

Ligterink Niels Sackler Laboratory for Astrophysics, Leiden Observatory

Martin Marie-Aline Harvard-Smithsonian Center for Astrophysics

McGuire Brett NRAO / Caltech

Misselt Karl University of Arizona

Muñoz-Caro Guillermo M. Center of Astrobiology (CAB)

Nahon Laurent SOLEIL

Öberg Karin Harvard-Smithsonian Center for Astrophysics

Orlando Thom Georgia Institute of Technology

Osaka Kazuya Institute of Low Temperature Science, Hokkaido University

Paardekooper Daniel Leiden University

Perera Thushara Illinois Wesleyan University

Rimola Albert Universitat Autonoma de Barcelona

Sanche Léon University of Sherbrooke

Shingledecker Christopher University of Virginia

Sibener Steven University of Chicago

Strittmatter Peter Steward Observatory, University of Arizona

Theulé Patrice Aix-Marseille University

Thomas Aaron University of Hawaii

Thorwirth Sven University of Cologne

Tran Katherine Wellesley College

Turner Andrew University of Hawaii at Manoa

Vidali Gianfranco Syracuse University

Watanabe Naoki Hokkaido University

Ziurys Lucy Arizona Radio Observatory, University of Arizona