Spectrum of doubly excited P-4(e) resonances in He-

The P-4(e) spectrum of He- has been treated by the complex coordinate rotation method within an extensive basis sets of r(ij)-correlated configurations. The energy position and width obtained for the lowest 1s2p(2) shape resonance are in very good agreement with the available experimental and theoretical data. The resonant parameters for five 1s(nl)(2), n = 3,...,7, Feshbach states, forming a regular two-electron ionization ladder, confirm a recent theoretical prediction of Themelis and Nicolaides (1995 J. Phys. B: At. Mol. Opt Phys. 28 L379). 16 other, hitherto unknown, doubly excited Feshbach and shape resonances have also been discovered in the energy region up to the 1s7p P-3(o) threshold. The Feshbach part of this spectrum shows regular character. The number of resonances connected with the 1snl(3)L thresholds increases with increasing n.