Eur. Phys. J. D (2015) 69: 86
https://doi.org/10.1140/epjd/e2015-60005-0

Regular Article

Effect of orthogonalization on total ionization cross sections by electron impact: application to small molecules

¹ LPQSD, Department of Physics, Faculty of Sciences, University Setif 1, 19000 Setif, Algeria
² SRSMC, UMR CNRS 7565, University of Lorraine, BP 70239, 54506 Vandoeuvre-lès-Nancy, France
³ USTHB, Faculty of Physics, Department of theoretical physics, 16111 Algiers, Algeria
⁴ Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia
⁵ Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, 2, chemin du Cyclotron, Box L7.01.07, 1348 Louvain-la-Neuve, Belgium
⁶ School of Mathematical Sciences, Ramakrishna Mission Vivekananda University, P.O. Belur Math, 711202 West Bengal, India

^a e-mail: shouamer@univ-setif.dz

Received: 2 January 2015
Published online: 24 March 2015

Abstract

Total ionization cross sections by electron impact are calculated for H₂O, NH₃ and CH₄ molecules by using an improved first Born approximation which has been previously applied for atomic targets by Bartlett and Stelbovics [P.L. Bartlett, A.T. Stelbovics, Phys. Rev. A 66, 012707 (2002)]. In this model a full orthogonalization of the final state to the initial state has been performed to evaluate the cross sections. One center wave functions are employed to describe the molecular orbitals. It is shown that the results obtained in the present model are immensely improved when compared with the first Born model without orthogonalization. Furthermore, an overall agreement is also observed when a comparison is made with the experimental data.