Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - A mystery solved?
T2 - photoelectron spectroscopic and quantum chemical studies of the ion states of CeCp3+
AU - Coates, Rosemary
AU - Coreno, Marcello
AU - DeSimone, Monica
AU - Green, Jennifer C.
AU - Kaltsoyannis, Nikolas
AU - Kerridge, Andrew
AU - Narband, Naima
AU - Sella, Andrea
PY - 2009/8/14
Y1 - 2009/8/14
N2 - The electronic states of CeCp3+ have been studied experimentally by variable photon energy photoelectron spectroscopy, and computationally using multi-configurational ab initio methods. Relative partial photoionisation cross section and branching ratio data are presented to confirm our previous conclusion that bands A and D in the valence photoelectron spectrum, despite their 3.2 eV separation, are produced by ionization of the single 4f electron of CeCp3 [M. Coreno, M. de Simone, J. C. Green, N. Kaltsoyannis, N. Narband and A. Sella, Chem. Phys. Lett., 432, 2006, 17]. The origin of this effect is probed using the CASSCF/CASPT2 approach. While configurations based on the canonical CASSCF orbitals are found to be an unreliable description of the ground and excited states of CeCp3+, the state-specific natural orbitals and their occupations yield greater insight, allowing us to characterize ion states in terms of the presence or otherwise of a Ce 4f-localised electron. Neither the CeCp3+ ground state (assigned to band A), and two excited states ((E) over bar (1)A' and (1)A '' , associated with band D), possess such a metal-based electron, as expected of f ionization. The E (1)A' and (1)A '' states differ from the ground state in having a significant Ce 5d population, arising from Cp -> Ce charge transfer, which accompanies f ionization, and which is responsible for the energetic separation of bands A and D in the valence photoelectron spectrum.
AB - The electronic states of CeCp3+ have been studied experimentally by variable photon energy photoelectron spectroscopy, and computationally using multi-configurational ab initio methods. Relative partial photoionisation cross section and branching ratio data are presented to confirm our previous conclusion that bands A and D in the valence photoelectron spectrum, despite their 3.2 eV separation, are produced by ionization of the single 4f electron of CeCp3 [M. Coreno, M. de Simone, J. C. Green, N. Kaltsoyannis, N. Narband and A. Sella, Chem. Phys. Lett., 432, 2006, 17]. The origin of this effect is probed using the CASSCF/CASPT2 approach. While configurations based on the canonical CASSCF orbitals are found to be an unreliable description of the ground and excited states of CeCp3+, the state-specific natural orbitals and their occupations yield greater insight, allowing us to characterize ion states in terms of the presence or otherwise of a Ce 4f-localised electron. Neither the CeCp3+ ground state (assigned to band A), and two excited states ((E) over bar (1)A' and (1)A '' , associated with band D), possess such a metal-based electron, as expected of f ionization. The E (1)A' and (1)A '' states differ from the ground state in having a significant Ce 5d population, arising from Cp -> Ce charge transfer, which accompanies f ionization, and which is responsible for the energetic separation of bands A and D in the valence photoelectron spectrum.
KW - ELECTRONIC-STRUCTURE
KW - PHOTOEMISSION SPECTRA
KW - CERIUM COMPOUNDS
KW - CEROCENE
KW - CE
KW - LANTHANIDE
KW - CE(ETA-C5H5)(3)
KW - COMPLEXES
KW - CHEMISTRY
KW - SUBSHELL
U2 - 10.1039/b902263e
DO - 10.1039/b902263e
M3 - Journal article
VL - 2009
SP - 5943
EP - 5953
JO - Dalton Transactions
JF - Dalton Transactions
SN - 1477-9226
IS - 30
ER -