Angular distribution in the double ionization of helium by fast electrons: Effect of target e-e correlations.

Abstract

Some kinematical arrangements in He(e,3e) process have been explored to ascertain the sensitivity of continuum electron-electron angular correlation to the electron-electron (e-e) correlation in the target wave function. The calculation has been done in the Coulomb-projected Born approximation with suitably chosen effective charges. It is found that the variation in the cross section is quite sensitive to the target e-e correlation when (i) the two low-energy ejected electrons are detected at fixed angles ${\mathrm{\ensuremath{\theta}}}_{\mathit{b}}$ and ${\mathrm{\ensuremath{\theta}}}_{\mathit{c}}$ but their energies ${\mathit{E}}_{\mathit{b}}$ and ${\mathit{E}}_{\mathit{c}}$ are varied such that ${\mathit{E}}_{\mathit{b}}$+${\mathit{E}}_{\mathit{c}}$ is held fixed, or (ii) one of the electrons is detected at some large fixed angle (say, 90\ifmmode^\circ\else\textdegree\fi{}) and the other angle ${\mathrm{\ensuremath{\theta}}}_{\mathit{c}}$ is varied at fixed energies.