New Process of Excitation Transfer in Helium

Abstract

Precise observations have been made on light emission from low triplet levels of helium gas traversed by a monoenergetic electron beam, with varying helium pressure and electron energy. In the past it has been customary to assign this triplet excitation to direct transfer from ${}_{}{}^1{}_{}{}^{}P$ states in flagrant violation of the Wigner rule and seemingly excessive cross sections for the transfer have been inferred.