Fully differential cross sections for singly ionizing 1-Mev p+He collisions at small momentum transfer: Beyond the first Born approximation

TL;DR

This paper calculates electron angular distributions in helium ionization by 1-MeV protons, comparing theoretical models beyond the first Born approximation with experimental data, highlighting the importance of electron-electron correlations.

Contribution

It introduces calculations using the 3C model with correlated helium wave functions to improve agreement with experimental data beyond the first Born approximation.

Findings

Good agreement with experimental data using the 3C model

Electron-electron correlations affect binary and recoil peak ratios

Second Born approximation improves accuracy over first Born

Abstract

We present calculations of the electron angular distributions in the single ionization of helium by 1-MeV proton impact at momentum transfer of 0.75 a.u. and ejected-electron energy of 6.5 eV. The results using the first and second Born approximations and the 3C model with different trial helium functions are compared to the experimental data. A good agreement between theory and experiment is found in the case of the 3C final state and a strongly correlated helium wave function. The electron-electron correlations in the He atom are found to influence the ratio of the binary and recoil peak intensities.