Higher order polarizabilities and the positron forward scattering problem: Convergence between calculated and measured cross sections in the very low energy regime

Abstract

We have employed a well established correlation-polarization model potential to calculate the elastic cross sections for positron collisions with O2 , N2 and CO2 from 0.01 eV to Eps. The description of the outer component of the positron-molecule potential was improved introducing higher polarizability and the hyperpolarizabilities terms. The obtained cross sections were applied in the forward correction of the measured total cross sections and much improved convergence between the calculated elastic cross sections and the corrected measurements was found.