Autoionization states of the positronium negative ion in exponential cosine-screened Coulomb potentials

Abstract

The $2s^2~^1{\rm S}^e$ autoionization resonance states of the positronium negative ion (Ps-) in exponential cosine-screened Coulomb potentials (ECSCP) are investigated using stabilization method. Highly correlated wave functions for Ps- are used to take into account the correlation effect of the charged particles. Results for resonance energies and widths are reported for the screening parameter in the range 0.0-0.07 (in a0 -1), to the best our knowledge, for the first time in the literature.