A new He- resonance in the excitation of the (2s2p)3P autoionising state by electrons

Four He- resonances with all three electrons in the n=2 shell are accessible by electron impact from the He ground state but only two resonances have been identified unambiguously in electron-helium scattering experiments. Experimental evidence for the presence of a He- resonance at 59.90 eV in the excitation cross section of the He**(2s2p)3P autoionising state is presented and discussed