TY - JOUR

T1 - Is cerocene Really a Ce(III) compound?

T2 - all-electron spin-orbit coupled CASPT2 calculations on M(eta(8)-C8H8)(2) (M = Th, Pa, Ce)

AU - Kerridge, Andrew

AU - Coates, Rosemary

AU - Kaltsoyannis, Nikolas

PY - 2009/3/26

Y1 - 2009/3/26

N2 - Spin-orbit free CASPT2 wave functions and energies are presented for the ground and 31 excited states of three f element sandwich Molecules; thorocene (ThCOT2), protactinocene (PaCOT2), and cerocene (CeCOT2). Ground-state metal-ring centroid distances are optimized at this level and show excellent agreement with experiment. The effects of spin-orbit coupling are included and are found to be negligible for the ground states of ThCOT2, and CeCOT2, for which comparison of the electronic excitation energies is made with experimental data. For PaCOT2, spin-orbit coupling is found to alter significantly the energies and nature of the ground and low-lying excited states, and good agreement is obtained with previous computational data. The ground state of CeCoT2 is found to be strongly multiconfigurational, though not in the same way as previously reported. The relationship of this result to previous computational and experimental data is discussed, as is the most appropriate way to view the electronic structure of CeCOT2. It is concluded that the occupations of the natural orbitals produce a more reliable description of the CeCOT2 ground state than does the configurational admixture.

AB - Spin-orbit free CASPT2 wave functions and energies are presented for the ground and 31 excited states of three f element sandwich Molecules; thorocene (ThCOT2), protactinocene (PaCOT2), and cerocene (CeCOT2). Ground-state metal-ring centroid distances are optimized at this level and show excellent agreement with experiment. The effects of spin-orbit coupling are included and are found to be negligible for the ground states of ThCOT2, and CeCOT2, for which comparison of the electronic excitation energies is made with experimental data. For PaCOT2, spin-orbit coupling is found to alter significantly the energies and nature of the ground and low-lying excited states, and good agreement is obtained with previous computational data. The ground state of CeCoT2 is found to be strongly multiconfigurational, though not in the same way as previously reported. The relationship of this result to previous computational and experimental data is discussed, as is the most appropriate way to view the electronic structure of CeCOT2. It is concluded that the occupations of the natural orbitals produce a more reliable description of the CeCOT2 ground state than does the configurational admixture.

KW - GROUND-STATE

KW - MOLECULAR STRUCTURE

KW - OXIDATION-STATE

KW - BASIS-SETS

KW - DENSITY

KW - COMPLEXES

KW - URANOCENE

KW - SPECTRA

KW - CERIUM

KW - PSEUDOPOTENTIALS

U2 - 10.1021/jp807804w

DO - 10.1021/jp807804w

M3 - Journal article

VL - 113

SP - 2896

EP - 2905

JO - Journal of Physical Chemistry A

JF - Journal of Physical Chemistry A

SN - 1089-5639

IS - 12

ER -