Positron interactions with nitrogen and oxygen molecules: elastic, inelastic and total cross sections

Abstract

Positron scattering cross sections, used for modelling particle transport in various media, are difficult to gather experimentally. As such, various cross section calculation methods have been developed to varying accuracy. The IAM-SCAR+I method has been improved upon recently to fulfil the optical theorem and the results for two important simple molecules, N2 and O2, are presented here. These results are compared to literature and our findings are comparable in most impact energy ranges.

Ionization cross sections for plasma relevant molecules

“…Besides, neither the BEB nor the DM method includes the contribution from indirect ionization such as excitation-autoionization and hence, at best, determines the direct ionization cross section. Further, looking into the optical potential approach adopted in this article for the calculation of inelastic cross section, it shows similarity to the formalism adopted by Garcia and co-workers [33,34]. The essential difference lies in the treatment of molecular targets.…”

“…Then screening corrections and interference terms are added to refine the molecular cross sections. In the present adopted SCOP method, the molecular geometry is consistently included in our codes and no other approximations or corrections are additionally needed to study a molecular target, though both versions of optical potential formalism have produced consistent and reliable cross sections not only for electron scattering, but for positron scattering as well [23,[33][34][35]. Further, there are other methods such as close coupling (CC) calculation, which are known to produce reliable ionization cross sections [36].…”

Recent studies with electrons, positrons and positronium

“…swarm physics illustrate the current focus of the field, with several contributed topical reviews[12,16,18,22] highlighting progress made up to now. Specifically, positron and positronium scattering or structure calculations on a range of targets were reported by Barp and Arretche[1], Hervieux and Chakraborty[3], Ellis-Gibbings et al[4], Arretche et al[5], Tenfen et al[10], Seidel and Arretche[11], DeMars et al[14], Ono et al[23], and Yazejian and Straton[24]. A comprehensive series of electron scattering, both theoretical and experimental, contributed topical reviews, covering a very wide variety of molecules, were contributed by Scarlett et al[12], Gorfinkiel[16], Song et al[18], and Lopes et al[22].…”