Electron-impact excitation of the doubly excited states of helium below the N=3 He{sup +} threshold
- Department of Physics and Astronomy, Schuster Laboratory, Manchester University, Manchester M139PL (United Kingdom)
Measurements of the doubly excited states of helium below the He{sup +}(N=3) threshold populated by electron impact are presented for a range of scattering angles and residual energies. The deduced values of the energies and widths for 11 of the optically forbidden states are compared with theoretical values, which shows the agreement to be good for the energies but poorer for the widths. The data verify propensity rules in Lin{close_quote}s [Adv. At. Mol. Phys. {bold 22}, 77 (1986)] K, T, A classification scheme for the cross sections. By comparing the 2s{sup 2}{sup 1}S{sup e} and 3s{sup 2}{sup 1}S{sup e} states at the scattering angle of 20{degree} and the residual energy of 40 eV, we obtain a dependence of n{sup {minus}10.1{plus_minus}0.8} for the cross section at these conditions. {copyright} {ital 1996} {ital The American Physical Society}
- OSTI ID:
- 432518
- Journal Information:
- Physical Review A, Journal Name: Physical Review A Journal Issue: 1 Vol. 55; ISSN 1050-2947; ISSN PLRAAN
- Country of Publication:
- United States
- Language:
- English
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