DOUBLY EXCITED (3)P(E) RESONANT STATES IN PS-

Doubly excited P-3(e) resonant states in Ps- are calculated using a method of complex-coordinate rotation. Resonance parameters (both resonance positions and widths) for doubly excited states associated with the n = 2, 3, 4, 5, and 6 thresholds of positronium atoms are evaluated using elaborate Hylleraas-type functions. In addition to ten Feshbach-type resonances lying below various Ps thresholds, we have identified three shape resonances, one each lying above the n = 2, 4, and 6 Ps thresholds. It is further noted that the energy levels for the present P-3(e) states are nearly degenerate with respect to the previously calculated P-1(o) states. Such a symmetric character suggests that the highly and doubly excited Ps-, similar to its counterpart in H-, would exhibit rovibrational behaviors analogous to those of XYX triatomic molecules.