Positron Impact Excitation Cross Section of Helium

Abstract

We have computed excitation cross section (ECS) of Helium (2¹S - 2¹P and 2³S - 2³P) by positron impact using coupled channel optical (CCO) method. Here we have compared the calculated ECS results for singlet-singlet excitation with other available theoretical data. The results are found in excellent agreement with convergent close coupling (CCC) and distorted wave approximation (DWA) calculations. For triplet-triplet transition, we have compared our results with available experimental results also. However some discrepancies suggested that more theoretical work is required in future.