Photoionization Cross Sections and Asymmetry Parameters for Ethylene

Abstract

We present the results of applications of the iterative Schwinger variational method to obtain photoionization cross sections and phoelectron angular distributions for ionization out of the four outermost valence orbitals 1b_(3u), 1b_(3g), 3a_g and 1b_(2u) of ethylene for photon energies ranging from near threshold to 30 eV. The observed resonance-like maxima in the cross sections for ionization of the 1b_(3g) and 3a_g orbitals are reproduced in our calculations. The disagreement between our cross sections and the experimental data for the 1b_(3u) orbital below 17 e V is attributed to autoionization, which is not accounted for in our calculations.