Molecular differential photoionization cross-section calculations with L2 basis functions in the random-phase approximation. Results for H2O

A computational procedure, based on the K-matrix technique, is presented to solve the random-phase-approximation equations for the description of excitations in the molecular electronic continuum using L2 basis functions. The proposed method has been applied to the calculation of the photoionization cross sections and asymmetry parameters of the three main valence ionization processes in H2O including the effect of the channel interaction. The comparison of the calculated quantities with the available experimental data shows a remarkable improvement for the integral cross sections as well as an amelioration of the angular distribution parameters with respect to the static-exchange results previously obtained by a similar computational technique.