CALCULATION OF PHOTOIONIZATION CROSS SECTIONS USING AB-INITIO WAVEFUNCTIONS AND THE PLANE WAVE APPROXIMATION

A method is outlined for the calculation of photoionization cross sections representing the initial state by a minimal basis set STO NG wavefunction and the final state by the plane wave approximation. Numerical results for several small molecules compare well with the band intensities in published ESCA spectra, and are superior to ESCA band intensities obtained from valence electron wavefunctions. For the UV region, ab-initio and valence electron calculations lead to comparable results