High-lying doubly excited resonances in Ps− interacting with screened Coulomb potentials

• Effect of screening on the resonance states of Ps− has been studied.
• High-lying doubly-excited resonance states of Ps− ion are calculated.
• The method of complex-scaling are used to extract resonance parameters.
• Highly correlated Hylleraas-type wave functions are used.
• Resonance parameters below the N = 4, 5, and 6 Ps thresholds are reported.

The effect of screened Coulomb potentials on the high-lying doubly-excited resonance states of the positronium negative ion has been investigated using the method of complex-scaling together with employing highly correlated Hylleraas-type wave functions. Resonance parameters (resonance energy positions and widths) below the N = 4, 5, and 6 Ps thresholds for various screening parameters are determined.