Asymmetric molecular-frame photoelectron angular distributions for C 1s photoejection from CO2; a theoretical study

Abstract

We report the results of ab initio calculations of cross sections and molecular-frame photoelectron angular distributions for C 1s ionization of CO2, and propose a mechanism for the recently observed asymmetry of those angular distributions with respect to the CO+ and O+ ions produced by subsequent Auger decay. The fixed-nuclei, photoionization amplitudes were constructed using variationally obtained electron-molecular ion scattering wave functions. We have also carried out electronic structure calculations which identified a dissociative state of the CO2++ dication that is likely populated following Auger decay. We show that a proper accounting of vibrational motion in the computation of the photoelectron angular distributions, along with reasonable assumptions about the nuclear dissociation dynamics, gives results in good agreement with recent experimental observations.