In this paper we report our calculations on several important total cross-sections (TCS$_s$) of positron impact on isoelectronic N₂ and CO molecules, treated in the complex spherical potential formalism. Basically the total (complete) cross-section $Q_T$ consists of elastic and inelastic contributions. Our total inelastic cross-section ($Q_{\text{inel}}$) contains ionization and electronic excitations together with positronium formation. Our goal here is to bifurcate $Q_{\text{inel}}$ further to deduce total ionization cross-section, using the `complex scattering potential–ionization contribution’ (CSP-ic) method of electron–atom/molecule scattering. The present range of positron energy is 15–2000 eV. All the resulting cross-sections are in a good general accord with the existing data. This work highlights the importance of various scattering channels in $e^+ - N_2$ and $e^+ - CO$ interactions at intermediate and high energies.

Considering interactions and scattering of positrons with argon (Ar) and krypton (Kr) atoms, we have calculated total cross-sections $(Q_{T} = Q_{el} + Q_{inel})$ using complex spherical potentials for these systems. In positron–atom scattering it is difficult to bifurcate the ionization and cumulative excitation contained in the total inelastic cross-section. An approximate method called CSP-ic (complex scattering potential-ionization contribution) similar to electron–atom scattering has been applied to bifurcate ionization and cumulative excitation cross-sections at energies from the threshold to 2000 eV. Adequate comparisons of the present results are made, with available data.