Core Level Shifts in Transition Metal Compounds

Ab initio SCF calculations of X-ray emission chemical shifts are presented for the molecules TiH 4 , TiH 3 F, TiF 4 , and TiF 2 . The calculated Ti K α 1,2 shifts parallel 3 d orbital populations through a coupling via the radial extension of the 3 p and 3 s orbitals. Anomalous results are obtained for TiF 2 , which was calculated in a closed-shell configuration differing from its ground state. Potential models for chemical effects in core level spectra are shown to violate the atomic virial theorem but have still value as semiempirical tools.