Electron impact ionization--excitation of Helium

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

Bochum

Congreso; 69th Annual Gaseous Electronics Conference; 2016

American Physical Society

We calculate triple differential cross sections (TDCS) for the process of ionization--excitation of Helium by fast electron impact in which the residual ion is leftin the n 2 excited state. We chose the strongly asymmetric kinematics used in the experiment performed by Dupr´{e} et al. [1]. In a perturbative scheme, forhigh projectile energies the four--body problem reduces to a three--body one [2] and, within that framework, we solve the time- independent Schr"{o}dingerequation with a Sturmian approach [3]. The method, based on Generalized Sturmian Functions (GSF), is employed to obtain the initial ground state ofHelium, the single-continuum state and the scattering wave function; for each of them, the GSF basis is constructed with the corresponding adequateasymptotic conditions. Besides, the method presents the following advantage: the scattering amplitudes can be extracted directly in the asymptotic region ofthe scattering solution, and thus the TDCS can be obtained without requiring a matrix element evaluation