Eur. Phys. J. D (2021) 75: 310
https://doi.org/10.1140/epjd/s10053-021-00326-x

Regular Article – Atomic and Molecular Collisions

Electronic excitation of benzene by low energy electron impact and the role of higher lying Rydberg states

¹ Instituto de Física “Gleb Wataghin”, Universidade Estadual de Campinas, 13083-859, São Paulo, Campinas, Brazil
² Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-580, São Paulo, Santo André, Brazil
³ Laboratoire de Chimie et Physique Quantiques (UMR 5626), Université de Toulouse, CNRS, UPS, 31062, Toulouse, France
⁴ College of Science and Engineering, Flinders University, Adelaide, Australia
⁵ Department of Actuarial Science and Applied Statistics, Faculty of Business and Information Science, UCSI University, 56000, Kuala Lumpur, Malaysia

^c fkossoski@irsamc.ups-tlse.fr

Received: 15 October 2021
Accepted: 6 December 2021
Published online: 20 December 2021

Abstract

Benzene is undoubtedly one of the most studied target molecules in electron scattering experiments and calculations. However, there is still a huge knowledge gap on the electronic excitation cross sections of this fundamental collision. Here, we report calculated differential and integral cross sections for elastic and electronic excitation, as well as total cross sections, for electron scattering by the benzene molecule, for impact energies in the 10–50 eV range. We have employed the Schwinger multichannel method, in two levels of approximation. By including extra diffuse functions in the second calculation, the role of higher lying Rydberg states in the multichannel coupling scheme was assessed. We found that such states have minor effects on the elastic and total cross sections. In contrast, the electronic excitation cross sections of the lower-lying bands decrease in magnitude when accounting for the higher Rydberg states, and this effect becomes more pronounced at lower impact energies. Our computed elastic cross sections are in quite good agreement with the available experimental data, whereas the comparison for the electronic excitation channels is still satisfactory. We also discuss the need for accurate excitation energies in order to properly compare theoretical and experimental electronic excitation cross sections.