Calculation of ionization potentials and electron affinities for molecules relevant for streamer initiation and propagation

We investigate different quantum chemical methods to compute ionization potentials and electron affinities for various molecules of interest to streamer propagation experiments in liquids. Solvation effects have been studied for the ionization potential using a polarizable continuum model. The ionization potentials can be reasonably well predicted by the methods used, but electron affinities are more problematic. We discuss possible reasons for these problems. Our primary interest in exploiting these calculations is to aid the understanding of discharges in liquids, and to help predict the utility of various additives for insulating liquids.