Photoelectron spectroscopy of transition metal complexes. Effect of electron relaxation on spectrum informativity

Orbital ionization energies are compared with the results of ab initio calculations for three-atomic linear BeCl₂, XeF₂, CrCl₂ and five-atomic tetrahedral TiCl₄, RuO₄ molecules to investigate the effect of electron relaxation in ions on the informativity of photoelectron spectra of molecules and complex compounds. For all compounds except CrCl₂ there is satisfactory agreement between theory and experiment in respect of the sequence and character of electronic levels and the orbital nature of chemical bonds. In the series of 3d metal tris-β-diketonates, for metal complexes of the second half of the series there are wide discrepancies between the photoelectron, X_α-DV, and ab initio data on the electronic structure of the complexes, which are due to electron relaxation in the ions. The calculations exaggerate the mixing of levels between the metal and ligands, since the energy splitting of the corresponding spin-orbitals (spin polarization) considerably exceeds the multiplet splitting of states corresponding to a vacancy on the ligand MO estimated from the photoelectron spectra. Translated fromZhurnal Struktumoi Khimii, Vol. 39, No. 6, pp. 1113–1120, November–December, 1998.