Page 74 - Book of Abstracts

th
8 Biannual Conference on Chemistry - CHEM 08

References:
Theoretical Soft X-ray Spectroscopy of Transition Metal

Compounds: Case Study of Cobalt complexes

Basmah H.Allehyani , Rifaat H. Hilal , Saadullah G. Aziz , Walid M. Hassan ,
2
1
1,2
1
Oliver Kühn and Sergey I. Bokarev
3
3
1 Chemistry Department, Faculty of science, King Abdulaziz University, Jeddah,
SA, Chemistry Department, Faculty of science, Cairo University, Giza, Egypt,
2
3 Institute of Physics, University of Rostock, Rostock, Germany. Email:
bbhhaa1@hotmail.com.
ABSTRACT
X-ray spectroscopy is one of the most powerful tools to access structure and properties
of matter in different states of aggregation. X-ray spectroscopic techniques probe the local
electronic structure of a particular atom in its environment. This is in contrast to UV/vis
spectroscopy, where transitions generally occur between delocalized molecular orbitals.
The combination of different absorption, emission (scattering) as well as photo- and
autoionization X-ray methods allows addressing various aspects of ultrafast dynamics
and identification of short-lived intermediates of catalytic reactions.1 However,
interpretation of complex experimental spectra and verification of experimental
hypotheses is a non-trivial task and a powerful first principles theoretical approach that
allows for a systematic investigation of a broad class of compounds is needed. An
additional complexity stems from strong electron correlation and spin-orbit coupling in
the core-excited electronic states.
X-ray absorption (XAS) and resonant inelastic scattering (RIXS) of [Co(H2O)6] 2+/3+ and
[Co(CN)6] complexes with special care to the effect of metal charge and ligand field
4-
stringth studied theoretically using the RASSCF/RASSI approach. This enables us to
quantify the L-edge excitations of electrons from the 2p core to unoccupied MOs which
containing information on the nature of metal−ligand interaction. For comparing
purpose, the spectra were calculated with the same basis set and active space. Specific
findings deduced from the analysis of the shape of the L-edge excitations and RIXS
spectra concern the efficiency of the theoretical methodology under investigation. The
notably different patterns of spectroscopic features in metal charge and ligand field
strength develop an efficient and versatile theoretical methodology for the treatment of
soft X-ray spectra of [Co(H2O)6] 2+/3+ and [Co(CN)6] complexes based on the
4-
multiconfigurational self-consistent field electronic structure theory combined with a
perturbative LS-coupling scheme for spin-orbit coupling.
[1] S. I. Bokarev, M. Khan, M. K. Abdel-Latif, J. Xiao, R. Hilal, S. A. Aziz, E. F. Aziz, O. Kuhn, "Unravelling the Electronic
Structure of Photocatalytic Manganese Complexes by L-Edge X-ray Spectroscopy", J. Phys. Chem. C, 2015, 119, 19192-
19200.
[2] J. Romanova, T. Miteva, A. Ivanova, A. Tadjer, M. Baumgarten, "An in-depth theoretical approach to the design of Cu(II)
hybrid-spin magnets", Phys. Chem. Chem. Phys., 2009, 11, 9545-9555.
[3] K. Atak, S. I. Bokarev, M. Gotz, R. Golnak, K. M. Lange, N. Engel, M. Dantz, E. Suljoti, O. Kuhn, E. F. Aziz, "Nature of
the Chemical Bond of Aqueous Fe2+ Probed by Soft X-ray Spectroscopies and ab Initio Calculations", J. Phys. Chem. B,
2013, 117, 12613-12618.

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