High resolution studies of core electron excitations in Ru3(CO)12 and the effects of metallic screening.

High resolution electron yield spectra of core electron excitations in condensed Ru3(CO)12 exhibit a pronounced shoulder in the C 1s→π* excitation, due to transitions into unoccupied π levels consisting of linear combinations of the 2π orbitals of the various CO molecular ligands. The O edge near edge spectrum shows a clear and pronounced σ shape resonance transition, about 2 eV lower in energy than in free CO. We develop an intuitive model, which correlates the differences in the relaxation energies associated with the various core electron excitations with changes in the metal to ligand charge transfer process. The consequences of these differences in the core hole screening process with respect to standard models relating the position of the σ shape resonance to the bond length are discussed also. [ABSTRACT FROM AUTHOR]