Absolute oscillator strengths for the photoabsorption, photoionization and ionic photofragmentation of phosphine. I. The valence shell

Abstract

Dipole (e, e) spectroscopy has been used to obtain the first reported measurements of the absolute photoabsorption oscillator strengths (cross sections) for the valence shell of phosphine in the equivalent photon energy range 5–130 eV. Dipole (e, e+ion) coincidence spectroscopy has been used to collect photoionization time-of-flight mass spectra from the first ionization potential up to 50 eV to yield ionic photofragmentation branching ratios. Absolute partial photoionization oscillator strengths for production of the molecular and fragment ions have been obtained from the measured absolute photoabsorption oscillator strengths, the photoionization efficiency and the ionic photofragmentation branching ratios. Radiation-induced breakdown pathways of phosphine have been deduced using observed ion appearance potentials and the presently reported partial photoion oscillator strengths, together with the known electronic state ionization potentials of PH 3. Absolute electronic state partial photoionization oscillator strengths have been derived by summing the appropriate portions of the ionic photofragmentation partial oscillator strengths according to the proposed radiation-induced breakdown scheme.