Photoelectron Studies of Ionic Materials using Molecular Beam Techniques

Photoelectron spectra of the monomeric species of several classes of ionic molecule have been obtained by crossing a molecular beam of the material with a photon beam containing photons of energies up to 50 eV (He I and He II lines). In this way electrons from the s 2, p 6 and d 10 shells of the relevant atoms (or ions) were ejected and studied by photoelectron spectroscopy. The spectra are found to be explicable in terms of simple ionic models in which polarization of both negative and positive ions but mainly the former are taken into account. Work is reported on the alkali halides and the halides of Tl, In, Sn and Pb.