Low energy (e, 2e) differential cross-section measurements on the 1π_gand 4σ_gmolecular orbitals of CO₂

Abstract

Experimental results are reported for the (e, 2e) differential ionization crosssection from the 3σ g and 1π u valence molecular orbitals of molecular nitrogen N 2 at incident electron energies between 25.6 and 76.7 eV. The measurements have been conducted in a coplanar symmetric geometry in an energy regime where ionization is sensitive to contributions from shape resonances and autoionizing doubly excited states. The results suggest that these additional channels may contribute to the measured cross-section. The measurements also display trends qualitatively similar to previous results at higher incident electron energies using the same geometry.

Comparison of experimental and theoretical triple differential cross sections for the single ionization ofCO2 (1πg)by electron impact

“…The results were compared with the same energy range results for the diatomic molecule N 2 . A double forward peak was observed at low angles and energies for the CO 2 1π g state but not N 2 [14]. TDCSs for CO 2 and N 2 molecules in coplanar asymmetric geometry at incident electron energies around 500-700 eV were measured by Lahmam-Bennani et al [15] for cases corresponding to large momentum transferred to the ion which yields larger recoil scattering.…”

“…Despite all this work, detailed experimental and theoretical examinations of triple differential cross section (TDCS) for electron-CO 2 collisions have been relatively few. The first experimental (e,2e) study was done by Hussey and Murray [14]. They presented differential ionization cross sections for low energy electron scattering from the 1π g and 4σ g orbitals of CO 2 for 10-80 eV incident electron energies in coplanar symmetric (e,2e) experiments.…”

Three-centre continuum wavefunction: application to the (e, 2e) simple ionization of the 1πg, 1πuand 3σumolecular orbitals of CO2by fast electron impact

“…The aim of the present work is to extend the TCC model to the three-centre case and apply it to the ionization of CO 2 , which is the most common linear three-centre target, for which (e, 2e) experiments have been realized [15,16]. Besides the direct interest of modelling the experiments, we want to verify if the variation of the multiply differential cross section (MDCS) of a three-centre target with the scattering and ejection angles can show interference patterns similar to those already predicted for the two-centre case [10].…”

(e,2e) simple ionization of CO2by fast electron impact: use of three-center parameterized continuum wave function and Dyson orbitals

“…We define E i , E s , and E e as the energy values of the incident, scattered, and ejected electrons, respectively. They must satisfy the following energy conservation equation with I = 13.77 eV representing the energy necessary to eject an electron from the 1π g orbit of the CO 2 target [9,17]. In our model we will consider only the active electron of the target.…”