Theoretical interpretation of photoelectron spectra for transition metal compounds. The He(I) and He(II) spectra of MF 2 molecules (M = Co, Ni and Cu)

Abstract

Calculated vertical ionization energies (VIEs) and relative intensities (RIs) have been used in interpreting He(I) and He(II) photoelectron spectra of MF 2 molecules, M being Co, Ni and Cu. VIEs have been obtained by the Green's function technique applying the semiempirical CNDO-UHF method. Within the framework of the Gelius-Siegbahn model, but utilizing the theoretical atomic cross-sections, the molecular photoionization cross-sections (and the corresponding relative intensities of spectral bands) have been calculated for He(I) and He(II) spectra of MF 2 molecules. A comparison of the theoretical and experimental VIEs and RIs shows that the procedure is useful in ascribing photoemission peaks at particular binding energies of He(I) and He(II) spectra to the set of molecular orbitals.