S-wave resonances in e⁺–He scattering below the Ps (<i>n</i> = 2) excitation threshold

Abstract

Two S-wave resonances in the positron–helium system are calculated using the stabilization method. A model potential for helium is used to represent the He+ ion core and the outer electron. Hylleraas-type wavefunctions are used to represent the correlation effects between the outer electron, the positron and the He+ core. Resonance energies and widths for two resonances lying below the Ps (n = 2) threshold are reported.