High-resolution threshold photoelectron and photoion spectroscopy of molecular nitrogen in the 15.0–52.7 eV photon energy range

Abstract

We have performed an extensive study of the threshold photoelectron spectrum of N2 over the valence ionization region 15.0–28.0eV under high-resolution conditions. In addition, we measured the high-resolution photoion spectrum of N2 over the same photon energy range. These complimentary views of ionization in molecular systems provide different perspectives of the mechanism for the production of both ions and threshold electrons. The studies are presented in the context of our current understanding of the relationship between: (i) the autoionization of neutral Rydberg states and direct photoionization to (ii) the production of electrons and the ionic states of nitrogen at threshold. In both cases (ions and threshold electrons) we have found a considerable amount of new information on the vibrational states of a number of neutral and ionic electronic states. The inner valence ionization region of nitrogen was also investigated using threshold photoelectron spectroscopy over the photon energy range (27.7–52.7eV) and is presented from the perspective of the formation of mixed-configuration ionic satellite states and the possibility of the involvement of ionic Rydberg states converging on the double ionization of nitrogen.