Dynamics of e+ + H(ns) → e+ + H(n's) with exponential cosine-screened Coulomb potentials

The dynamics of ns -> n's excitations of hydrogen by positron impact with exponential cosine-screened Coulomb potentials (ECSCPs) has been investigated using a distorted-wave theory in momentum space. Making use of a simple variationally determined wave function for the hydrogen atom, it has been possible to obtain the distorted-wave scattering amplitude in a closed analytical form. A detailed study has been made on differential and total cross sections in the energy range 20-250 eV. To the best of our knowledge, such a study on the differential and total cross sections for inelastic positron-hydrogen collisions with ECSCPs is the first reported in the literature.