Dynamics of Positron Scattering from Lithium, Sodium and Potassium Atoms in Quantum Plasmas

The effects of quantum plasma on the dynamics of positron scattering from the ground state of alkali atoms (lithium, sodium and potassium atoms) have been studied within the framework of a two-state approximation which incorporates the elastic channel and the positronium formation channel. Exponential cosine screened Coulomb potential is considered as the effective potential for the description of the quantum plasma. The ground state wave function and energy of the alkali atoms are calculated quite accurately by resorting to the ‘method of model potential’ and variational principle. The changes introduced by the quantum plasma in the differential and the total cross sections for the elastic and rearrangement scattering have been studied in details for the incident positron energy varying from 10 to 500 eV. It is observed that the varying screening strength of the background plasma causes appreciable changes in the cross sections.