Electron impact ionization?excitation of Helium

L. U. ANCARANI; A. I. GOMEZ; G. GASANEO; D. M. MITNIK; M. J. AMBROSIO

Ruhr

Conferencia; 69TH ANNUAL GASEOUS ELECTRONICS CONFERENCE; 2016

University Bochum

We calculate triple differential cross sections (TDCS)for the process of ionization?excitation of Helium by fast electron impactin which the residual ion is left in the n=2 excited state. We chose thestrongly asymmetric kinematics used in the experiment performed byDupr´e et al. [1]. In a perturbative scheme, for high projectile energiesthe four?body problem reduces to a three?body one [2] and, within thatframework, we solve the time- independent Schr¨odinger equation witha Sturmian approach [3]. The method, based on Generalized SturmianFunctions (GSF), is employed to obtain the initial ground state of Helium,the single-continuum state and the scattering wave function; foreach of them, the GSF basis is constructed with the corresponding adequateasymptotic conditions. Besides, the method presents the followingadvantage: the scattering amplitudes can be extracted directly in theasymptotic region of the scattering solution, and thus the TDCS can beobtained without requiring a matrix element evaluation. [1] C. Dupr´eet al. (1992) J. Phys. B 25, 259. [2] M.J. Ambrosio et al. (2014) Phys.Rev. A 89, 012713. [3] G. Gasaneo et al. (2013) A