Regular Article

Low-energy-electron scattering by CH₃CN^★

Departamento de Física, Universidade Federal do Paraná, Caixa Postal 19044, 81531-990 Curitiba, Paraná, Brazil

^a e-mail: bettega@fisica.ufpr.br

Received: 21 July 2017
Received in final form: 7 October 2017
Published online: 12 December 2017

Abstract

We report integral and differential cross sections for the elastic scattering of low-energy electrons by methyl cyanide (CH₃CN), also known as acetonitrile. The cross sections were computed using the Schwinger multichannel method implemented with pseudopotentials. The fixed-nuclei scattering calculations were performed in the static-exchange and static-exchange plus polarization approximations for energies up to 15 eV. In our calculations with polarization effects, we found a π^* shape resonance at around 2.22 eV and a broad structure associated to a σ^* shape resonance at around 7 eV. The low-lying resonance was assigned to the electron capture by the two-fold degenerate π^* orbital of the E symmetry of C_3v group; the second was assigned to a σ^* shape resonance in the A₁ symmetry. We compared our cross sections with theoretical results and experimental data available in the literature, and in general we found good agreement for the positions of the two resonances.