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Structure, bonding, and spectroscopyStructure, bonding, and spectroscopyof actinides in crystalsof actinides in crystals
A quantum chemical perspectiveA quantum chemical perspective
Zoila BarandiaránZoila Barandiarán
Departamento de Química &Departamento de Química &Instituto Universitario Instituto Universitario dede Ciencia de Materiales Nicolás Cabrera Ciencia de Materiales Nicolás Cabrera
Universidad Autónoma de Madrid, Spain.Universidad Autónoma de Madrid, Spain.
http://www.uam.es/zoila.barandiaran
2
Structure, bonding, and spectroscopyStructure, bonding, and spectroscopy of actinides in of actinides in crystalscrystals
A quantum chemical perspectiveA quantum chemical perspectiveActinidesActinides
spectroscopyspectroscopy
quantum chemical perspectivequantum chemical perspective
in crystalsin crystals
advanced nuclear energy systemsadvanced nuclear energy systemschallenge challenge basicbasic and applied and applied researchresearchsocietal interest: societal interest: controversial energy source; security & waste controversial energy source; security & waste problemsproblems
open shells: 5f, 6d, 7sopen shells: 5f, 6d, 7s
extreme conditions (temperature, extreme conditions (temperature, pressurepressure))ions in crystals, solid fuel and fission products (UOions in crystals, solid fuel and fission products (UO22, PuO, PuO22))
large manifolds of excited states: 5flarge manifolds of excited states: 5fNN, 5f, 5fN-1 N-1 6d6d11, and others, and others
spectroscopy: a basic tool spectroscopy: a basic tool expected/exotic electronic structures beyond the gsexpected/exotic electronic structures beyond the gs
figerprints of local structure and bondingfigerprints of local structure and bonding models of coordination chemistrymodels of coordination chemistry
3
UU4+4+ in Cs in Cs22GeGeFF66
Actinide ions doped in solids – an exampleActinide ions doped in solids – an example
point defect:point defect:
+ local distortion+ local distortion + new electronic states in the energy + new electronic states in the energy gapgap
how many states ? how to calculate them ?how many states ? how to calculate them ? N electrons formally in 5f, 6d shells in a crystal fieldN electrons formally in 5f, 6d shells in a crystal field
4
f and d electrons in an octahedral fieldf and d electrons in an octahedral field
PaPa4+4+ in Cs in Cs22ZrClZrCl66
5
f and d electrons in an octahedral fieldf and d electrons in an octahedral field
UU4+4+ in Cs in Cs22ZrClZrCl66PaPa4+4+ in Cs in Cs22ZrClZrCl66
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Structure, bonding, and spectroscopyStructure, bonding, and spectroscopy of actinides in of actinides in crystalscrystals
A quantum chemical perspectiveA quantum chemical perspective
A quantum chemical model A quantum chemical model (for ground and excited states)(for ground and excited states)
ResultsResults
an overviewan overview type of resultstype of results accuraciesaccuraciesa show casea show case
Conclusions and what is next Conclusions and what is next
7
Defect clusterDefect clusterEmbedding hostEmbedding host
• Relativistic (spin-orbit)Relativistic (spin-orbit)• Electron correlationElectron correlation• Large fLarge fnn and f and fn-1 n-1 dd1 1 manifoldsmanifolds
ffnn , f , fn-1n-1dd11
embedding-AIMPembedding-AIMP
• relativistic core-AIMP relativistic core-AIMP (ECP)(ECP)• wave-function based correlation wave-function based correlation methodsmethods (CASSCF + MS-CASPT2)(CASSCF + MS-CASPT2)
A quantum chemical modelA quantum chemical model for ground and excited states for ground and excited states
8
MaterialMaterialCsCs22GeFGeF6 6 withwith
UU4+4+ impurities impurities
Ab InitioAb Initio Model Potentials Model Potentials as as Effective Effective Core+EmbeddingCore+Embedding Potentials Potentials
ActiveActive (cluster valence) (cluster valence)
(UF(UF66))2- 2- 68 electrons68 electrons
InactiveInactive (environment) (environment)
CsCs22GeFGeF66
• Non-parametric & produced directly from the frozen orbitalsNon-parametric & produced directly from the frozen orbitals• Inactive-active explicit interactionsInactive-active explicit interactions
– Coulomb, Coulomb, ExchangeExchange, , Linear independenceLinear independence
InactiveInactive (core) (core)
U U [[KrKr],4f ],4f
F 1s F 1s
9
Embedded Cluster HamiltonianEmbedded Cluster Hamiltonian
Relativistic Cowan-Griffin-Wood-Boring Hartree-Fock Relativistic Cowan-Griffin-Wood-Boring Hartree-Fock all-electron all-electron atomicatomic calculations calculations
+ + Frozen core approximationFrozen core approximation
CoulomCoulombb
Exchange + scalar relativisticExchange + scalar relativistic Linear Linear independenceindependence
+ + AIMP recipe for representation of AIMP recipe for representation of
operatorsoperators
long-range long-range locallocallocallocal
10
Embedded Cluster HamiltonianEmbedded Cluster Hamiltonian
Relativistic Cowan-Griffin-Wood-Boring Hartree-Fock Relativistic Cowan-Griffin-Wood-Boring Hartree-Fock all-electron all-electron atomicatomic calculations calculations
+ + Frozen core approximationFrozen core approximation
CoulomCoulombb
Exchange + scalar relativisticExchange + scalar relativistic Linear Linear independenceindependence
+ + AIMP recipe for representation of AIMP recipe for representation of
operatorsoperators
short-rangeshort-range
spectral spectral representatiorepresentatio
nn
11
Embedded Cluster HamiltonianEmbedded Cluster Hamiltonian
Relativistic Cowan-Griffin-Wood-Boring Hartree-Fock Relativistic Cowan-Griffin-Wood-Boring Hartree-Fock all-electron all-electron atomicatomic calculations calculations
+ + Frozen core approximationFrozen core approximation
+ + AIMP recipe for representation of AIMP recipe for representation of
operatorsoperators
CoulomCoulombb
Exchange + scalar relativisticExchange + scalar relativistic Linear Linear independenceindependence
12
Embedded Cluster HamiltonianEmbedded Cluster Hamiltonian
Perfect crystal latticePerfect crystal latticeloop over loop over lattice ionslattice ions until convergence until convergence
perform a single embedded-ion calculation (SCF, perform a single embedded-ion calculation (SCF, CASSCF)CASSCF)produce its produce its embedding-AIMPembedding-AIMP out of its orbitals out of its orbitalsupdate the lattice embedding potentialsupdate the lattice embedding potentials
end loopend loop
SSelf-elf-Consistent onsistent EEmbedded mbedded IIon on calculationscalculations
13
Embedded Cluster HamiltonianEmbedded Cluster Hamiltonian
14
Spin-orbit coupling / electron correlationSpin-orbit coupling / electron correlation
Spin-orbit splittingsSpin-orbit splittings
depend on:depend on: spin-orbit couplingsspin-orbit couplings spin-free spectrumspin-free spectrum
which demand:which demand: small CI space small CI space PP large CI space large CI space GG
Use Use GG space for the space for the spin-free spectrumspin-free spectrum
Use Use PP space for the space for the spin-orbit couplingsspin-orbit couplings
An aproximate decoupling ofAn aproximate decoupling of correlationcorrelation andand spin-orbitspin-orbit
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Spin-free state shifted HamiltonianSpin-free state shifted Hamiltonian
Use Use PP space for the space for the spin-orbit couplingsspin-orbit couplings
small CI space small CI space PP large CI space large CI space GG
Use Use GG space for the space for the spin-free spectrumspin-free spectrum
16
Spin-free state shifted HamiltonianSpin-free state shifted Hamiltonian
Use Use PP space for the space for the spin-orbit couplingsspin-orbit couplings
small CI space small CI space PP large CI space large CI space GG
Use Use GG space for the space for the spin-free spectrumspin-free spectrum
17
Spin-free state shifted HamiltonianSpin-free state shifted Hamiltonian
Use Use PP space for the space for the spin-orbit couplingsspin-orbit couplings
Use Use GG space for the space for the spin-free spectrumspin-free spectrum
– Codes:Codes:
MOLCASMOLCAS
COLUMBUSCOLUMBUS
Björn O. Roos et al., Lund UniversityRuss M. Pitzer et al., Ohio State University
EPCISOEPCISO Valérie Vallet et al., Université de Lille
18
– Cluster: Cluster: (AnL(AnL66))q-q-
Details of the calculationsDetails of the calculations
EmbeddedEmbedded--cluster cluster (embedding AIMP (embedding AIMP for ionic solidsfor ionic solids))
spin-free: spin-free: CASSCFCASSCF//CASPT2CASPT2
EffectivEffective ce core ore ppotential otential (Cowan-Grif(Cowan-Griffin-Wood-Boring based fin-Wood-Boring based AIMP)AIMP)
spin-orbit: spin-orbit: sfss-SOCI [MRCI(S)]sfss-SOCI [MRCI(S)]
– Embedding Embedding potentials:potentials:~ 500 AIMPs ~ 500 AIMPs + 3000 point charges + 3000 point charges
atat experimental sitesexperimental sites so that E(R) is stableso that E(R) is stable
19
Details of the calculationsDetails of the calculations
EmbeddedEmbedded--cluster cluster (embedding AIMP (embedding AIMP for ionic solidsfor ionic solids))
spin-free: spin-free: CASSCFCASSCF//CASPT2CASPT2
EffectivEffective ce core ore ppotential otential (Cowan-Grif(Cowan-Griffin-Wood-Boring based fin-Wood-Boring based AIMP)AIMP)
spin-orbit: spin-orbit: sfss-SOCI [MRCI(S)]sfss-SOCI [MRCI(S)]
– Core AIMPs:Core AIMPs:
An: [Xe,4f] 5d,6s,6p, 5f,6d,7sAn: [Xe,4f] 5d,6s,6p, 5f,6d,7s
Cl: [Ne] 3s,3pCl: [Ne] 3s,3p
– Valence basis sets:Valence basis sets:
An: (14s10p12d9f3g)/[6s4p5d4f1g]An: (14s10p12d9f3g)/[6s4p5d4f1g]
Cl: (7s7p1d)/[3s4p1d]Cl: (7s7p1d)/[3s4p1d]
20
Details of the calculationsDetails of the calculations
EmbeddedEmbedded--cluster cluster (embedding AIMP (embedding AIMP for ionic solidsfor ionic solids))
spin-free: spin-free: CASSCFCASSCF//CASPT2CASPT2
EffectivEffective ce core ore ppotential otential (Cowan-Grif(Cowan-Griffin-Wood-Boring based fin-Wood-Boring based AIMP)AIMP)
spin-orbit: spin-orbit: sfss-SOCI [MRCI(S)]sfss-SOCI [MRCI(S)]
– SA-CASSCF:SA-CASSCF: [5f,6d,7s][5f,6d,7s]NN
– MS-CASPT2:MS-CASPT2: An: 5dAn: 5d10106s6s226p6p6 6 [5f,6d,7s][5f,6d,7s]NN + 6 x Cl: 3s + 6 x Cl: 3s223p3p66
21
Details of the calculationsDetails of the calculations
EmbeddedEmbedded--cluster cluster (embedding AIMP (embedding AIMP for ionic solidsfor ionic solids))
spin-free: spin-free: CASSCFCASSCF//CASPT2CASPT2
EffectivEffective ce core ore ppotential otential (Cowan-Grif(Cowan-Griffin-Wood-Boring based fin-Wood-Boring based AIMP)AIMP)
spin-orbit: spin-orbit: sfss-SOCI [MRCI(S)]sfss-SOCI [MRCI(S)]
– spin-free-state-shifted Spin-Orbit CI:spin-free-state-shifted Spin-Orbit CI:
Wood-Boring spin-orbit operator scaled by 0.9Wood-Boring spin-orbit operator scaled by 0.9
Basis of double-group adapted functionsBasis of double-group adapted functions
MRCI(S) CAS[5f,6d,7s]MRCI(S) CAS[5f,6d,7s]NN
22
Results: type of resultsResults: type of results
Local structure (ground/excited Local structure (ground/excited states)states)
bond lengths, vibrational frequenciesbond lengths, vibrational frequencies
23
Results: type of results Results: type of results
Local structure (ground/excited Local structure (ground/excited states)states)
bond lengths, vibrational frequenciesbond lengths, vibrational frequenciesWave functions (and their analyses)Wave functions (and their analyses) bonding interactionsbonding interactions
24
Results: type of results Results: type of results
Local structure (ground/excited Local structure (ground/excited states)states)
bond lengths, vibrational frequenciesbond lengths, vibrational frequenciesWave functions (and their analyses)Wave functions (and their analyses) bonding interactionsbonding interactionsAbsorption/emission spectraAbsorption/emission spectra
transition energies, transition moments, emission transition energies, transition moments, emission lifetimeslifetimes
25
Results: type of results Results: type of results
Local structure (ground/excited Local structure (ground/excited states)states)
bond lengths, vibrational frequenciesbond lengths, vibrational frequenciesWave functions (and their analyses)Wave functions (and their analyses) bonding interactionsbonding interactionsAbsorption/emission spectraAbsorption/emission spectra
transition energies, transition moments, emission transition energies, transition moments, emission lifetimeslifetimes
Mechanisms of energy transferMechanisms of energy transfer upconversion/quantum cutting mechanismsupconversion/quantum cutting mechanisms
Green-to-blue light upconversion in CsGreen-to-blue light upconversion in Cs22ZrClZrCl66: : UU4+4+
UU4+4+ impurities impurities
5f5f22 levels levels
UOUO222+2+ impurities impurities
5f5f116d6d11 levels levels
26
Results: type of results Results: type of results
Local structure (ground/excited Local structure (ground/excited states)states)
bond lengths, vibrational frequenciesbond lengths, vibrational frequenciesWave functions (and their analyses)Wave functions (and their analyses) bonding interactionsbonding interactionsAbsorption/emission spectraAbsorption/emission spectra
transition energies, transition moments, emission transition energies, transition moments, emission lifetimeslifetimes
Mechanisms of energy transferMechanisms of energy transfer upconversion/quantum cutting mechanismsupconversion/quantum cutting mechanismsPressure effectsPressure effects
CsCs22NaYClNaYCl66:Ce:Ce3+3+ under pressure under pressure
P=0
P=25 kbar
f1
d(t2g)1
d(eg)1
27
Results: type of results Results: type of results
Local structure (ground/excited Local structure (ground/excited states)states)
bond lengths, vibrational frequenciesbond lengths, vibrational frequenciesWave functions (and their analyses)Wave functions (and their analyses) bonding interactionsbonding interactionsAbsorption/emission spectraAbsorption/emission spectra
transition energies, transition moments, emission transition energies, transition moments, emission lifetimeslifetimes
Mechanisms of energy transferMechanisms of energy transfer upconversion/quantum cutting mechanismsupconversion/quantum cutting mechanismsPressure effectsPressure effects
28
Results: accuracies Results: accuracies (validation + applications)(validation + applications)
CeCe PrPr NdNd PmPm SmSm EuEu GdGd TbTb DyDy HoHo ErEr TmTm YbYb LuLu
ThTh PaPa UU NpNp PuPu AmAm CmCm BkBk CfCf EsEs FmFm MdMd NoNo LrLr
CsCs22NaYClNaYCl66
CsCs22ZrClZrCl66
CsCs22GeFGeF66
SrFSrF22
BaFBaF22
YAG YAG (Y(Y33AlAl55OO1212))
Bond distancespresumably (no EXAFS available)0.01Å
Bond length changes very good(exceptions?)
Cs2ZrCl6:Pa4+
YAG:Ce3+
Vibrational frequencies
5% Ce3+,Pr3+,Sm2+,Pa4+
Electronic transitions 10% Ce3+,Pa4+,U3+,U4+
Pressure induced shiftsof electronic transitions
semiquantitative Sm2+
Intensidades relativas semiquantitative Ce3+,U3+,U4+CsCaBrCsCaBr33
29
UU4+ 4+ in fluoridesin fluorides
UU4+ 4+ 5f5f22, 5f, 5f116d6d1 1 manifolds manifolds ~90 excit~90 excited statesed states
fluorides fluorides large transparency windowlarge transparency window
● ● UV solid state laserUV solid state laser
● ● Phosphor based on quantum cutting or cascade Phosphor based on quantum cutting or cascade luminescenceluminescence
PotentialityPotentiality as as
Results: a show case Results: a show case
Predicting the luminescence of a new material Predicting the luminescence of a new material + experimental & theoretical study+ experimental & theoretical study
30
5f5f22 levels levels
UV solid state laserUV solid state laser
Strong, broad, fast Strong, broad, fast 6d6d→→5f 5f
luminescenceluminescence
quantum cutting orquantum cutting orcascade cascade
luminescenceluminescence5f5f116d6d11 levelslevels
11SS00
YLiFYLiF44:U:U4+4+ YFYF33:U:U4+4+
Weak, slow, two-step 5fWeak, slow, two-step 5f→→5f5fluminescenceluminescence
31
UV solid state laserUV solid state laserquantum cutting orquantum cutting or
cascade cascade luminescenceluminescence
UU4+4+ in Cs in Cs22GeGeFF66
•The electronic structure of the 5fThe electronic structure of the 5f22 manifold manifold •The 5fThe 5f1 1 6d6d11 manifold manifold
• Promote the synthesis and experimental studyPromote the synthesis and experimental study
• An unexpected 5fAn unexpected 5f1 1 7s7s1 1 manifold: U-trapped manifold: U-trapped excitonsexcitons
32
CsCs22GeFGeF66:U:U4+4+, a potential quantum cutter or solid state , a potential quantum cutter or solid state laser ?laser ?
11SS00
5f5f22 levels levels
33
5f5f22 levels levels
quantum cutting orquantum cutting orcascade luminescencecascade luminescence
5f5f116d6d11 levelslevels
11SS00
11SS00
33PP00
5f5f116d6d11 levelslevels
33HH44
5f5f22 levels levels
CsCs22GeFGeF22:U:U4+4+, a potential quantum cutter or solid state , a potential quantum cutter or solid state laser ?laser ?
34
11SS00
5f5f116d6d11 levelslevels
5f5f22 levels levels
CsCs22GeFGeF22:U:U4+4+, a potential quantum cutter or solid state , a potential quantum cutter or solid state laser ?laser ?
5f5f22 levels levels
UV solid state laserUV solid state laser
Strong, broad, fast Strong, broad, fast 6d6d→→5f luminescence5f luminescence
5f5f116d6d11 levelslevels
11SS00
35
Miroslaw Karbowiak, University of Wroklaw
• • growth of Csgrowth of Cs22GeFGeF66:U:U4+4+ single crystals single crystals
• • experimental absorption spectrum (7 experimental absorption spectrum (7 K)K)
• • broad, intense bands 37000 – broad, intense bands 37000 – 45000cm45000cm-1-1
• • no appreciable fine vibronic no appreciable fine vibronic structurestructure
• • most prominent at 38000 cmmost prominent at 38000 cm-1-1
Absorption spectrum.Absorption spectrum.
36
• • Theoretical spectrumTheoretical spectrum
•• 2500cm2500cm-1 -1 too high too high (0.3 eV) (0.3 eV) (7 %)(7 %)
•• Five 5fFive 5f116d6d11 origins: 1A origins: 1A1g1g → → iTiT1u1u ( i = 1,5) ( i = 1,5)
Absorption spectrum.Absorption spectrum.
37
Absorption spectrum.Absorption spectrum.
•• Intensities:Intensities:+ most prominent band 1A+ most prominent band 1A1g1g → →
1T1T1u1u
+ relative intensities ok, + relative intensities ok, - except for 1A- except for 1A1g1g → → 2T2T1u1u
•• 2500cm2500cm-1 -1 too high too high (0.3 eV) (0.3 eV) (7 %)(7 %)
•• Five 5fFive 5f116d6d11 origins: 1A origins: 1A1g1g → → iTiT1u1u ( i = 1,5) ( i = 1,5)
• • Theoretical spectrumTheoretical spectrum
38
Emission spectrum.Emission spectrum.
1T1T1g1g
1T1T2g2g
2T2T1g1g, 2T, 2T2g2g
3T3T2g2g
5f5f22 levels levels
5f5f116d6d11 levels levels1E1Euu
39
Large Stokes shift: 6200 cmLarge Stokes shift: 6200 cm-1-1
Emission spectrum.Emission spectrum.
1T1T1g1g
1T1T2g2g
2T2T1g1g, 2T, 2T2g2g
3T3T2g2g
1A1A1g1g
1E1Euu
40
Spontaneous emission Spontaneous emission lifetime: lifetime:
Emission spectrum.Emission spectrum.
Experiments underwayExperiments underway
41
An unexpected 5fAn unexpected 5f117s7s11 manifold: U-trapped exciton? manifold: U-trapped exciton?
2.154, 2.154, 2.174,2.174, 2.21 2.21 Å Å 2.092.09
U(IV)
• • Bond length Bond length ~~ U(V) U(V) clustercluster• • Very diffuse 7s Very diffuse 7s orbitalorbital• • Energy sensitive to basisEnergy sensitive to basis set delocalization set delocalization
U - trapped exciton ?
42
An unexpected 5fAn unexpected 5f117s7s11 manifold: U-trapped exciton? manifold: U-trapped exciton?
Impurity-trapped excitonImpurity-trapped exciton
D. S. McClure, et al. D. S. McClure, et al. Phys. Rev. B, 32, 8465 (1985)Phys. Rev. B, 32, 8465 (1985)
SrFSrF22:Yb:Yb2+2+ anomalous emissionanomalous emission
““The excited state ... could be called an The excited state ... could be called an impurity-trapped impurity-trapped excitonexciton, since it consists of a, since it consists of a bound electron-hole pair bound electron-hole pair with with thethe hole localized on the impurity hole localized on the impurity and theand the electron on electron on nearby lattice sites...”nearby lattice sites...”
““The trappedThe trapped exciton geometry exciton geometry is probablyis probably that expected that expected forfor a trivalent impurity ion, a trivalent impurity ion, YbYb3+3+...” ...”
YbYb2+2+ → → YbYb3+ 3+ + 1e(Sr) very short bond + 1e(Sr) very short bond lengthlength localised hole delocalised localised hole delocalised
43
7s MO 7s MO [5f[5f117s7s11-2-233AA2u2u (UF (UF66CsCs88))6+6+]]7s AO 7s AO [5f[5f117s7s11--33F UF U4+4+]]
AnalAnalysis of the wavefunctionsysis of the wavefunctions
44
•• Hole localized Hole localized in the U(5f)in the U(5f)
• • ~~ U(V) bond length U(V) bond length
Diffuse orbitals Diffuse orbitals of Ln/An in solids of Ln/An in solids can lead tocan lead to impurity trapped excitonsimpurity trapped excitons
Microscopic description of Microscopic description of an impurity trapped an impurity trapped exciton exciton
•• Electronic densityElectronic density in the frontier of in the frontier of
the UFthe UF66 unit unit
45
Wavefunction based Wavefunction based ab initioab initio embedded cluster calculations on embedded cluster calculations on
LnLnq+q+ and An and Anq+q+ impurities in ionic hosts impurities in ionic hosts – Reliable enough (complement experiments, predict)Reliable enough (complement experiments, predict)– Can be used to progress in the understanding ofCan be used to progress in the understanding of
Advanced Nuclear Energy SystemsAdvanced Nuclear Energy Systems
ConclusionsConclusions
What is next ?What is next ?Nuclear fuel and nuclear wastes materialsNuclear fuel and nuclear wastes materials
– UOUO22 (experimental spectroscopy available) , PuO (experimental spectroscopy available) , PuO22
– diluted UOdiluted UO22/PuO/PuO22 mixtures UO mixtures UO22:Pu:Pu4+4+, PuO, PuO22:U:U4+4+
Transuranium systems (the fTransuranium systems (the f77 configuration) configuration)
– CmCm3+3+ in Cs in Cs22NaYClNaYCl6 6 (experimental spectroscopy available)(experimental spectroscopy available)
– and Amand Am2+2+ and Bk and Bk4+4+
46
AcknowledgmentsAcknowledgments
Luis SeijoLuis Seijo
Belén Ordejón Belén Ordejón
Ana Muñoz
José Luis PascualJosé Luis Pascual
meme
José GraciaJosé Gracia
Fernando Fernando Ruipérez Ruipérez
on campus, UAM 2006on campus, UAM 2006
Goar SánchezGoar Sánchez
Noémi BarrosNoémi Barros
in La Sierra, Madrid 2007in La Sierra, Madrid 2007
http://www.uam.es/quimica/aimp/
47
AcknowledgmentsAcknowledgments
• Miroslaw Karbowiak, Miroslaw Karbowiak, Faculty of Chemistry, University of Wroclaw, Wroclaw, Faculty of Chemistry, University of Wroclaw, Wroclaw, PolandPoland
• Norman Edelstein,Norman Edelstein, Lawrence Berkeley National Laboratory, Berkeley, Lawrence Berkeley National Laboratory, Berkeley, California, USACalifornia, USA
• Björn Roos, Rolandh Lindh,Björn Roos, Rolandh Lindh, (MOLCAS)(MOLCAS) Lund University, Lund, SwedenLund University, Lund, Sweden• Russell Pitzer, Russell Pitzer, (COLUMBUS) Ohio State University, Columbus, Ohio, USA(COLUMBUS) Ohio State University, Columbus, Ohio, USA• Valérie Vallet, Jean-Pierre Flament Valérie Vallet, Jean-Pierre Flament (EPCISO) Université de Lille, Lille, France(EPCISO) Université de Lille, Lille, France
• Spanish Ministry of Education and Science, Spanish Ministry of Education and Science, DGI-BQU2002-01316,DGI-DGI-BQU2002-01316,DGI-
CTQ2005-08550. CTQ2005-08550.
48
Structure, bonding, and spectroscopy Structure, bonding, and spectroscopy of actinides in crystals.of actinides in crystals.
A quantum chemical perspectiveA quantum chemical perspective
Universidad Autónoma de MadridUniversidad Autónoma de Madrid