Photoelectron spectroscopic studies of dinitrogen tetroxide and dinitrogen pentoxide

Abstract
Rapid expansion of vapour through a nozzle inlet system has been used for the study of some molecular species normally only present at pressures much above those usually obtaining at the ionization region of a photoelectron spectrometer. The He I photoelectron spectra for dinitrogen tetroxide and dinitrogen pentoxide obtained in this way are presented and discussed. Comparison is made with Gaussian ab initio molecular orbital calculations and with the spectra of the dissociated species. The relation to nitric acid is also noted. Several possible geometrical structures are considered in the case of dinitrogen pentoxide. It is shown that a planar form with a N–O–N angle of the order of 120° is most consistent with the p. e. s. results.