The 1,3D○ resonance states of positronium negative ion using exponential correlated wave functions

Abstract

The doubly excited 1,3D○ resonance states of Ps- associated with N=3, N=4 and N=5 Ps thresholds have been investigated using highly accurate correlated wave functions with exponents generated by a quasirandom process. Resonance parameters (both resonance positions and widths) are extracted in the framework of the stabilization method and the complex coordinate rotation method. In addition to many Feshbach resonances below the various Ps thresholds, we have identified two 1 D○ shape resonances with one each lying above the N=3 and N=4 thresholds, respectively, and two 3 D○ shape resonances with one each lying above the N=3 and N=5 thresholds, respectively. The 1 D○ shape resonance associated with N=3 Ps threshold and some other Feshbach resonances are reported for the first time in the literature.