Photoionization of molecular hydrogen

A theoretical formulation of diatomic photoionization is given in terms of an entirely body-frame Hund’s case b description. Within this formalism, the electronic wavefunctions for both the bound initial state and the free final state of photoionization are described with conventional configuration interaction wavefunctions expanded in a Gaussian basis. The Stieltjes imaging procedure is used to recover the continuum oscillator strength from the discrete eigenspectrum. The continuum oscillator strength is combined with variationally determined vibrational wavefunctions to yield model photoelectron spectra, specific v–v ionization cross sections, a photoion kinetic energy spectrum, dissociative ionization spectra, and a total photoionization spectrum. For a series of photon energies near threshold, cross sections from these calculations are compared with previous theoretical results and with recent experimental measurements.