The stability of the ground state for positronic sodium

Abstract

The existence of a stable ground state for the exotic atom is demonstrated by using a modified version of the stochastic variational method to solve the Schrödinger equation for a positron and valence electron moving under the influence of a model potential. The model potential consists of the direct interaction between the positronium and the Hartree - Fock wavefunction for the alkali ion. The exchange potential between the valence electron and the core electrons is approximated with a local potential. The structure of positronic sodium is best described as a slightly stretched and polarized positronium atom orbiting the core at distances of the order of 10 - . It is found that positronic sodium is stable against decay into with a binding energy of 0.000177 Hartree.