Differential and integral cross sections for electron impact excitation of the n3S, n1S and n3P (n=2,3) levels in He

Abstract

Differential and integral electron impact excitation cross sections are reported for the n3S, n1S and n3P (n=2,3) levels in He. Differential cross sections were measured at 30, 50 and 100 eV impact energies in the 10' to 135' angular range, extrapolated to 0 and 180', and then integrated over all angles to obtain integral cross sections at these three incident electron energies. In addition, differential cross sections were measured by excitation of the n3S (n=2,3,4,5), n1S and n3P (n=2,3,4) levels at 60 eV impact energy and 30' scattering angle. Theoretical cross sections based on first-order many-body theory (FOMBT) are also reported for these three final state symmetries for the 30-500 eV impact energy range. These new experimental and theoretical results are compared with other data.