Abstract
We have observed a broad -wave resonance at about 50 eV primary energy in the angular distribution of electrons scattered after excitation of the state of helium. The resonance has a width of about 15 eV and affects the differential excitation cross section by more than 3 orders of magnitude. It is suggested that this resonance is associated with the temporary formation of triply excited states of the negative helium ion.
- Received 31 May 1972
DOI:https://doi.org/10.1103/PhysRevLett.29.327
©1972 American Physical Society