Experimental study of the resonances 2s21S, 2p21D and 2s2p1P of the helium atom in energy spectra of electrons ejected in H+-He collisions (below 150 keV)

Abstract

The most important experimental results concerning the 2s2 1S, 2p2 1D and 2s2p1P resonances of the helium atom, as observed in energy spectra of ejected electrons, are given. Characteristic parameters are obtained numerically with Shore's formula (1969). The shape of the resonance is studied with Shore's parameter a, in the angular range 16.5 degrees to 160 degrees and for 33 to 150 keV proton energies; additional results concerning only the parameter q have been obtained at 10 degrees ejection angle, down to 26 keV proton energy. The intensity of the resonances is also measured in the same angular and energy ranges, and is characterized by Shore's parameter b. The results are compared with other experimental or theoretical works by means of the annulment diagram for the parameter a. This method permits the authors to synthesize all the experimental data actually available up to 500 keV.