Ground state and resonance state of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>Ps</mml:mi><mml:mo>−</mml:mo></mml:msup></mml:math>in plasmas with various Debye lengths

Abstract

We have made an investigation on the resonances for positronium negative ion ${\mathrm{Ps}}^{\ensuremath{-}}$ in various model plasma environments. The $2{s}^{2}\phantom{\rule{0.2em}{0ex}}^{1}S^{e}$ autoionization resonance state in ${\mathrm{Ps}}^{\ensuremath{-}}$ ion is determined by calculating the density of resonance states using the stabilization method. We have also performed accurate variational calculations to obtain ground-state energy eigenvalues of ${\mathrm{Ps}}^{\ensuremath{-}}$ for various Debye lengths. A screened Coulomb potential obtained from the Debye model is used to represent the interaction between the charged particles. A correlated wave function has been used to represent the correlation effect between the three charge particles. The calculated resonance energies and widths for various Debye parameters ranging from infinity to a small value along with the ground-state energies are reported.