Photoelectron angular distribution in valence shell ionization of heteroaromatic molecules studied by the continuum multiple scattering Xα method

Photoelectron angular distributions are calculated for the valence shell ionization of heteroaromatic molecules of pyridine, pyrazine, pyrimidine, pyrrole, and furan by the continuum multiple scattering X(x method. The asymmetry parameters exhibit strong energy dependences in ionization from g orbitals but are almost invariant in ionization from a orbitals, in good agreement with experimental results. The asymmetry parameters in ionization from nonbonding orbitals appear generally higher than those in ionization from bonding orbitals. These features are interpreted in terms of the Coulomb phase and photoelectron angular distribution in the molecular frame.