Energy dependence of the (e,2e) recoil peak to binary peak ratio across He (2p2)1

Abstract

The (e,2e) recoil peak to binary peak ratio as a function of the ejected-electron energy is reported for helium autoionizing levels (2p 2 ) 1 D and (2s2p) 1 P . A special out-of-plane geometry is used where the ejected electrons are detected in a plane that includes the momentum transfer axis but is perpendicular to the scattering plane. The measured recoil peak to binary peak ratio is a dimensionless quantity that can be directly compared with calculations. A second-order model in the projectile-target interaction correctly reproduces the observed energy dependence and magnitude of the ratio, while a first-order model does not.

Hyperfine-changing transitions in3He II and other one-electron ions by electron scattering

“…Here we added the physical n = 3 states plus a number of pseudostates to approximate the effect of the higher-lying Rydberg states as well as the ionization continuum on the numerical predictions. This model has been tested in great detail on several occasions, including the description of the initial bound state and the ejectedelectron−residual-ion interaction in calculations of electron-impact ionization (Sakelashvili et al 2005;Bellm et al 2006;deHarak et al 2014).…”