Ground-state energy and relativistic corrections for positronium hydride

Abstract

Variational calculations of the ground state of positronium hydride (HPs) are reported, including various expectation values, electron-positron annihilation rates, and leading relativistic corrections to the total and dissociation energies. The calculations have been performed using a basis set of 4000 thoroughly optimized explicitly correlated Gaussian basis functions. The relative accuracy of the variational energy upper bound is estimated to be of the order of 2$\ifmmode\times\else\texttimes\fi{}$10${}^{\ensuremath{-}10}$, which is a significant improvement over previous nonrelativistic results.