Theoretical study on positron scattering by benzene over a broad energy range

Abstract

In this paper two theoretical methodologies, the Schwinger multichannel (SMC) method and the independent atom model with the screening corrected additivity rule (IAM-SCAR), were employed to study positron scattering by benzene over a broad impact energy range. The SMC calculations were carried out in the static plus polarization approximation, accounting for the elastic channel, for impact energies up to 20 eV. The IAM-SCAR method covered energies up to 1000 eV to provide total, elastic, ionization, excitation, and positronium formation cross sections. In the low-energy region we discuss how the description of the polarization effects affects the cross sections. In particular, our calculations support the existence of a bound state in the positron scattering by benzene, in agreement with previous predictions by Young and Surko [Phys. Rev. A 77, 052704 (2008)NIMBEU0168-583X10.1103/ PhysRevA.77.052704]. Disciplines Engineering | Science and Technology Studies Publication Details Barbosa, A. Souza., Blanco, F., Garcia , G. & Bettega, M. H. F. (2019). Theoretical study on positron scattering by benzene over a broad energy range. Physical Review A, 100 (4), 042705-1-042705-7. This journal article is available at Research Online: https://ro.uow.edu.au/eispapers1/3298 PHYSICAL REVIEW A 100, 042705 (2019) Theoretical study on positron scattering by benzene over a broad energy range Alessandra Souza Barbosa ,1,* Francisco Blanco,2 Gustavo García,3,4 and M. H. F. Bettega1 1Departamento de Física, Universidade Federal do Paraná, Caixa Postal 19044, 81531-980 Curitiba, Paraná, Brazil 2Departamento de Estructura de la Materia, Física Térmica y Electrónica, Universidad Complutense de Madrid, Plaza de Ciencias 1, 28040 Madrid, Spain 3Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 113-bis, 28006 Madrid, Spain 4Centre for Medical Radiation Physics, University of Wollongong, NSW 2522, Australia (Received 16 May 2019; published 9 October 2019) In this paper two theoretical methodologies, the Schwinger multichannel (SMC) method and the independent atom model with the screening corrected additivity rule (IAM-SCAR), were employed to study positron scattering by benzene over a broad impact energy range. The SMC calculations were carried out in the static plus polarization approximation, accounting for the elastic channel, for impact energies up to 20 eV. The IAM-SCAR method covered energies up to 1000 eV to provide total, elastic, ionization, excitation, and positronium formation cross sections. In the low-energy region we discuss how the description of the polarization effects affects the cross sections. In particular, our calculations support the existence of a bound state in the positron scattering by benzene, in agreement with previous predictions by Young and Surko [Phys. Rev. A 77, 052704 (2008)]. DOI: 10.1103/PhysRevA.100.042705