Calculation of the molecular photoionization cross sections in the UV region. I. Diatomic molecules.

Abstract

The total and partial photoionization cross sections and the angular distributions of the photoelectrons in the UV region have been calculated employing the one-center deformed Coulomb waves obtained by the pseudo-potential method of Schneider and Berry for diatomic molecules H 2, N 2, CO and O 2. In comparison with the experimental results, the agreement is generally satisfactory from threshold to the incident photon wavelength of 580 Å except in the region where intense autoionization bands exist, while the energy dependences of the partial cross sections are often different from the observed results. The relative errors of the approximations are estimated to be less than 30 %, both for the total cross sections and the angular distributions in the region in which the photoelectron energy is smaller than 0.2 a.u. In our results, the energy dependences of the angular distributions agree with the observed results, and angular distributions for the ionization of π and σ u orbitals are found to be strongly dependent on the final states.