Photoemission from alkali halides: Energies and line shapes

Abstract

Energies and line shapes are calculated for photoemitted electrons from core and valence states in alkali halides. Energies are obtained by assuming that the holes are localized at lattice points and by using the point-ion model. The usual energy terms are obtained, including the ionization potential of the free ion, the Madelung energy, and the Mott-Littleton relaxation energy. An exact solution of the point-ion model is presented, which derives a new energy term from relaxation. The inclusion of this term considerably improves the agreement between theory and experiment for threshold energies. In addition, the phonon relaxation energy and line shapes are calculated for ten salts.