The width and Shape of the Lines. The Fluorescence Yield

Abstract

The shape and width of the different spectral lines — x-ray, emission, Auger, photoelectron — are all determined by the same fundamental principles, which makes it worthwhile to combine our examination of these questions into a single chapter. We will discuss the various factors involved in line broadening in Sec. 9.1: spontaneous transitions, distortions caused by the equipment, Doppler broadening, etc. A quantity closely related to natural linewidth — the fluorescence yield, which is characteristic of the relative role of a radiation and Auger decay of a state with a vacancy — is the topic of Sec. 9.2. The natural linewidth and fluorescence yield as a function of the nuclear charge, one- and many-electron quantum numbers, and the approximate invariance of these quantities that occurs for some configurations is studied in Sec. 9.3.