Solid state broadening in Auger spectra

Abstract

Some Auger spectra in the gas phase show extremely sharp lines and a great deal of fine structure while the Auger spectra of solids, even at high resolution, lack this detailed fine structure and generally have much broader peaks. In an effort to understand the broadening processes which occur on condensation of a gas or vapour to the solid phase, several solids for which high resolution gas phase data exists have been studied. The result of measurements of the M 45N 45N 45 Auger spectrum of cadmium are reported and comparison is made with the vapour phase data. Although the solid data contains considerable quasi-atomic fine structure the lines are broader than the vapour phase and by matching computer broadened vapour phase data to the experimental data an estimate of the individual line widths may be made. The relative intensities of the lines in the simulation agree closely with the solid data if loss processes are considered. Measurements have also been made on the same Cd transition in CdS and in this material the Auger lines are much broader than in Cd metal and the fine structure has almost disappeared. Results are also reported of measurements of the Auger spectra of solid rare gases made with the aid of a UHV cryostat capable of operating at temperatures down to 10 K. The gases studied were Xe, Ar and Kr and again comparison with computer broadened gas data enable the broadening of individual Auger lines to be estimated. Measurements of the line breadths have been made at various temperatures and the results of these experiments will be discussed in terms of lifetime and lattice vibrational broadening.