Photoionization Cross Sections and Asymmetry Parameters for the Valence Shell of Methanol

Abstract

Theoretical cross sections for photoionization of the methanol valence orbitals in covering a region up to 80 eV beyond the first ionization potential are reported. The molecular quantum defect orbital, MQDO, method, which has proved to be reliable in previous applications to molecular photoionization, has been used. To our knowledge, predictions of electronic partial cross section profiles on this molecule are made here for the first time, and we are not aware of any reported experimental data. Partial cross sections for production of parent and fragment ions of methanol have also been calculated and compared with previous measurements. In addition, the MQDO method has been used to calculate the angular distribution of photoelectrons for the valence orbitals of methanol over the 11-50 eV photon energy range. Our results are compared with experimental data, showing a good agreement in most cases. We hope that the present results might be of use in atmospheric and interstellar chemistry, where this molecule plays an important role.