Positronium formation and ionization of atoms and diatomic molecules by positron impact

In this article, we aim to calculate positronium formation and ionization cross-sections (direct and total) for C, N and O atoms and their diatomic molecules. A modified version of the well-known SCOP (Spherical Complex Optical Potential) and CSP-ic (Complex Scattering Potential-ionization contribution) formalisms are used for this calculation. In the present study, a phenomenological model recently introduced to obtain the threshold for absorption is used with a slight modification which helped us to distinguish various inelastic channels. This phenomenological model has improved our results, which are found to be in a reasonable agreement with the existing measurements. Most of the results predicted in this article are reported for the first time, hence more experiments are needed to be done to validate the present findings.Copyright (C) EPLA, 2017