Resolution and signal-to-background enhancement in gas-phase electron spectroscopy

Abstract

The most important factors contributing to line broadening and background intensity in electron spectra are identified and new design principles for high quality measurements are presented. It is shown that time‐dependent potential gradients in the gas cell are responsible for a large part of the ‘‘normal’’ line broadening, while scattering processes inside the gas cell are responsible for a large part of the background intensity. By designing the experiment according to these results, gas‐phase electron spectra can be recorded routinely at an instrument resolution level of better than 5 meV even at comparatively high gas cellpressures necessary to give high intensity for weak lines, and in principle unlimited counting times, at a much improved signal‐to‐background level. The resulting improvements in the spectral quality are demonstrated by spectra of Ar and HBr.