Theoretical study of ultraviolet photoelectron spectra of carbonyl systems: CO,Cr(CO)6, and CO/Cu(100)

Abstract

We present calculations of partial-channel photoionization cross sections and photoelectron spectra in the ultraviolet energy region of the carbonyl systems CO, Cr(CO)${}_{6}$, and CO/Cu${}_{14},$ the latter system modeling CO/Cu(100). The dependence on photon energy, including He I and He II spectra, and on the particular ionization channel has been investigated for the three systems by means of the independent-channel static exchange method. It is found that the method is able to reproduce all essential trends and features of the spectra as well as the energy dependence of the cross sections. The COCu${}_{14}$ model can be used to reproduce the organization of states in the spectra of CO/Cu(100) and for the photon energy dependence of the individual channel cross sections, while the relative cross sections between the different parts of the spectra can only be qualitatively assessed due to the limited representation of the metal density of states in the cluster model.