Physical Review A
Electron impact ionization, Helium -- Electronic excitation, Ionization of gases
Probabilities and cross sections for ionization plus excitation in helium produced by fast heavy-particle impact have been evaluated. In these calculations, contributions from shake-off, time ordering, and independent interactions of the frozen-target electrons with the projectile are included. A comparison is made to recent experimental observations for the ratio of excitation-ionization to single-ionization total cross sections. A comparison is also made to calculations of excitation-ionization by fast electron impact.
Ionization-excitation of helium by fast, charged particles, L. Nagy, J. Wang, Jack C. Straton, and J. H. McGuire, Phys. Rev. A 52, R902 (1995).