Studies of Molecular Photoruptures by using 2 Dimension (2+1) and (3+1) REMPI-TOF

Jingming Long15/09/2010

About project

WHY

WHAT High Energy Rydberg States of Molecules; Spectroscopy and Photofragmentation processes;

A fundamental role in various photochemical and photophysical processes, and so on

Resonance Enhanced Multiphoton Ionization –Time of Flight (REMPI-TOF) ---2D (2+1) REMPI, (3+1)REMPIREMPI-current (University of Iceland,Iceland)

HOW

Synchrotron studies (Paul Sherrer Institute, Switzerland)

Two color, Nanosecond(UV/Vis) + Femtosecond(IR) experiment (University of Bergen,Norway)

About project

CONDITION

Excimer(308nm XeCl)Dye Laser( Lambda Physik) SHG, Sirah, Vaccum chambeDiffusion pump, turbo pumpLecroy oscilloscope 400MHz/2.5GS/Sand so on

Instruments:

Prof. Agust KvaranDr. Victor Huasheng WangPh.D student Kristján Matthíasson

Group:

Collaborators: Professors J.P. Hansen and F. Øyvind , University of Bergen

Dr. Erik Horsdal, University of Aarhusand so on

outoutout

Voltagedevider

HV-2Kv

HX nozzle

TurboPump

TOF

lense

MCP/iondetector

oscilloscope

computer

Excimer Laser

Inout

Dye-Laser

SHG

Timedelay

laser control

Pellin Brocaprism

SHG controlInInIn

REMPI-TOF

Laser beam

Experimental equipment

Experimental equipment

Experimental equipment

HV+

0

-

Iondetector

Titanium sapphire

Dye laser

Field ionizationequipment

SHG

Pumppulse

Delayd/probepulse

Laserpulse

Sketch of the experimental setup to perform two-color experiments

University of Bergen

Main research compounds

i) Hydrogen halides (HX; X = Cl, Br, I)

ii) Halogens, X2 and interhalogens XY; X,Y = Cl, Br, I, X ≠ Y

iii) Freons, CFnXm; X = Cl, Br, I.

25

20

15

10

5

x103

8908089060890408902089000

j 3

-(1), v'=0

J'=1 J'=2 J'=3 J'=4 J'=5 J'=6

V1

J'=3 J'=2

H+

35Cl

+

H35

Cl+

37Cl

+

H37

Cl+

J'=7

J'=1

40

35

30

25

20

15

10

8908089060890408902089000

H37

Cl+

H35

Cl+

35Cl

+

H+

37Cl

+

Typical 2D REMPI-TOF graph

2h

1h

Summarization of the first half year of 2010

Old Dye Laser New Dye Laser

PD REMPI PD REMPI

Tektronix × × × ×

Lecroy × × × ×

PD: Power DependentOld dye laser: LumonicsNew dye laser: Scanmate Pro

Parts of LabVIEW programs

10

9

8

7

6

5

x103

100009500900085008000

9000

8000

7000

6000

5000

200190180170160

11

10

9

8

7

6

5

x103

20001900180017001600

6200

6000

5800

5600

5400

5200

5000

4800

10095908580

Different horizontal resolution at the same vertical resolution for mass spectrum

500 Pnts 10 000 Pnts

50 000 Pnts1000 Pnts

After next triggerWhat’s its value??

Different vertical resolution at the same horizontal resolution for mass spectrum

10

9

8

7

6

5

x103

9600940092009000

35

30

25

20

9600940092009000

Vertical resolution:1/65536

Vertical resolution:1/256

Example---HCl mass spectrum

30

25

20

15

10

5

0

-5

x103

17.217.016.816.616.4x10

3

35Cl+

H35

Cl+

37Cl

+ H37

Cl+

52

51

50

49

x1

03

370365360355

Old data

New data

Improvement

What’s the meaning?

More work for data processing?

Larger file size?

Higher resolution?

More time?

NO

YES

NO

YES

Old New

Manual Automatic

0~255/1Byte500pnts

0~65535/2ByteMax 50000pntsAt 2us

More than 2sTransmitted time

Less than 1s

500*1*(100cm-1/0.1cm-1)Byte

50000*2*(100 cm-1/0.1cm-1)Byte

Larger uncertain,Mass spectrum overlap

Weaker background of spectra? YES Smoothness

Plan for the latter half year of 2010

Perform the experiment of 2D (3+1) REMPI-TOF of HClTry to obtain the unexplored REMPI spectra of High Rydberg statesThen analyze, make assignments…If everything goes well, prepare to write relevant academic papers.

Work with Kari to finish the measurement and analysis of (2+1) REMPI experiment of CF3Br

Plan for the latter half year of 2010

To design and finish a Igor pro “toolkit” contains a series of procedures toProcess REMPI-TOF experimental data, perform simulations and so on, which can be shared by our group easily.For example, the procedures we has finished, REMPI IntegrateV2.2,Mass IdentifyV1.0.

During this period

To optimize the REMPI-TOF LabVIEW program. Make it easy to operate and also be used in teaching of undergraduate experiment.