Electron impact excitation of the 1(1)S-->3(1)P transition in helium.

Abstract

In the first direct application of the electron-photon coincidence technique for differential cross-section measurements, experimentally determined ratios of the differential cross sections for the electron impact excitation of the $1^{1}S\ensuremath{\rightarrow}2^{1}P$ to the $1^{1}S\ensuremath{\rightarrow}3^{1}P$ transitions are presented at 30 and 40 eV incident electron energies. Differential cross sections for the $1^{1}S\ensuremath{\rightarrow}3^{1}P$ transitions are derived by normalizing these ratios to available experimental differential cross sections for the $1^{1}S\ensuremath{\rightarrow}2^{1}P$ transition.