Resonance states of Ps - using correlated wave functions

We have investigated the Fe1,3 resonance states of positronium negative ion below the N=3, 4 and 5 Ps thresholds using highly correlated exponential wave functions. Resonance parameters (positions and widths) are extracted employing both the stabilization method and the complex-coordinate rotation method. In addition to many Feshbach resonances below the various Ps thresholds, we have identified two Fe1 shape resonances with one each lying above the N=3 and N=5 thresholds, respectively. We have also identified three Fe3 shape resonances with one lying above the N=3 threshold and two lying above N=4 threshold. The Fe1,3 shape resonances associated with N=3 Ps threshold and some other Feshbach resonances are reported for the first time in the literature.