Electron impact excitation of the metastable He(23S)

The first-order many-body theory is applied to study the inelastic collision of unpolarized electrons with helium in the 2 3 S excited state. The authors calculate differential cross sections (DCS) and integral cross sections (ICS) for 2 3 S to 2 3 P, 3 3 S, 3 3 P transitions and the alignment and orientation parameters for the 2 3 S to 2 3 P, 3 3 P transitions. The calculated DCS for the transition 2 3 S to 2 3 P is in good agreement with published theoretical and experimental results. The general behaviour of the alignment and orientation parameters for He 2 3 S to 2 3 P transition is compared with that of the Na 3 2 S to 3 2 P transition.