Exponential correlated basis in Schwinger variational principle for positronium formation in hydrogen

Abstract

An exponential correlated basis set is tested within the framework of multi-channel Schwinger variational principle in the momentum space. It is found that inclusion of only the positron-electron correlation in the basis set is enough to obtain accurate results for all significant partial waves for ground state positronium formation in positron-hydrogen collisions at low and intermediate energies (6.856–75 eV). Results are in conformity with other accurate variational and non-variational calculations as well as observed data available in the literature.