Ab Initio Calculations of X-ray Spectra: Atomic Multiplet and Molecular Orbital Effects in a Multiconfigurational SCF Approach to the L-Edge Spectra of Transition Metal Complexes.
A new ab initio approach to the calculation of X-ray spectra is demonstrated. It combines a high-level quantum chemical description of the chemical interactions and local atomic multiplet effects. We show here calculated L-edge X-ray absorption (XA) and resonant inelastic X-ray scattering spectra for aqueous Ni(2+) and XA spectra for a polypyridyl iron complex. Our quantum chemical calculations on a high level of accuracy in a post-Hartree-Fock framework give excellent agreement with experiment. This opens the door to reliable and detailed information on chemical interactions and the valence electronic structure in 3d transition-metal complexes also in transient excited electronic states. As we combine a molecular-orbital description with a proper treatment of local atomic electron correlation effects, our calculations uniquely allow, in particular, identifying the influence of interatomic chemical interactions versus intra-atomic correlations in the L-edge X-ray spectra.
†Department of Physics, Stockholm University, AlbaNova University Center, 106 91 Stockholm, Sweden.
Ida
I
Josefsson
‡Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany.
Kristjan
K
Kunnus
‡Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany.
Simon
S
Schreck
‡Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany.
Alexander
A
Föhlisch
§Inorganic Chemistry and Catalysis, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, Netherlands.
Frank
F
de Groot
‡Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany.
Philippe
P
Wernet
†Department of Physics, Stockholm University, AlbaNova University Center, 106 91 Stockholm, Sweden.
Michael
M
Odelius
RASSCF calculations; X-ray spectroscopy; resonant inelastic X-ray scattering; spectrum simulations; transition metal ions