A kinematic and experimental investigation of the (e,2e) simulation of photoelectron spectroscopy

Abstract

A general expression has been derived for the coincidence intensity in (e,2e) scattering experiments at small momentum transfers. The relationship with photoelectron spectroscopy using both polarized and unpolarized radiation is discussed. The predictions of the expression have been tested using a rotatable analyser which allows measurements to be made at ejection angles of 54.7 degrees and 90 degrees . Measurements at 54.7 degrees on He, Ne and Ar verify the most significant result of the analysis, namely the existence of a magic angle at which the coincidence intensity is independent of the angular anisotropy factor beta . At an ejected angle of 90 degrees the predicted beta dependence is observed for helium. The expected independence from beta of the coincidence intensity at 90 degrees and an energy loss of 22 eV is checked by comparing branching ratios for ionization of N₂ and CO with photoelectron data.