Valence ionized states of open-shell and closed-shell organometallic compounds studied by two-dimensional Penning ionization electron spectroscopy and ab initio MO calculations

摘要

Outer valence ionized electronic states of open-shell organometallic compounds are difficult to determine due to mixing of spin states and large electron correlation effects. We have studied two-dimensional Penning ionization electron spectroscopy (2D-PIES) [1] for some closed-shell [2,3] and open-shell [4] organometallic compounds. By collisional Penning ionization electron spectroscopy, the orbital reactivity of ionization process can be connected with spatial extending of respective molecular orbitals outside of the boundary surface of a colliding excited rare gas atom A~* to a target molecule M (A~* + M → A + M~+ + e~-), since the transition probability for the electron transfer from an occupied MO to the inner singly occupied orbital of A~* depends mainly on the spatial overlap between the related orbitals. The change of the orbital reactivity as a function of collision energy between metastable He~*(2~3S) atoms and target molecules, which is collision energy dependence of partial ionization cross sections (CEDPICS), can be observed by the 2D-PIES. In this study, we have applied 2D-PIES and high level ab initio MO calculations.