Positronium formation in neon and argon

Abstract

Cross sections for the formation of positronium in the scattering of positrons by neon and argon atoms have been calculated using the Born and a distorted-wave approximation. The Born approximation values are greater than the experimental estimates of Coleman et al. (1975), although they are in closer agreement with the results of Kauppila et al. (1976) (argon only). However, the distorted-wave approximation values are smaller than the experimental ones except for the energy range between the positronium and excitation thresholds.