High-angular-momentum (L >= 3) doubly excited resonance states of the positronium negative ion

We present a complex-coordinate rotation calculation of the doubly excited high-angular-momentum (L greater than or equal to 3) resonance states of th e positronium negative ion, Ps(-), associated with the N=3, N=4, and N=5 th resholds of the Ps atom. Products of Slater-type orbitals are used to repre sent the two-electron wave functions. For the Pa N=5 threshold, states with angular momentum up to L=8 are calculated. Results for doubly excited intr ashell states are used to construct the supermultiplet structures of the en ergy levels of Ps-, revealing rotational and vibrational series similar to those for an XYX triatomic molecule. [S1050-2941(99)09808-X].