Transitions between Rydberg Levels of Helium Induced by Electron Collisions

Electronic transfer rates from levels with principal quantum number p from 8 to 14 have been measured in an afterglow helium plasma at electron temperatures from 390 to 2000^∘{}K. While the total transfer rates are in satisfactory agreement with both classical and quantum treatments, transitions with |Δp|>1 are found to have a substantial probability; this favors a classical treatment in this energy range.