Energy and angular distributions of electrons from ion impact on atomic and molecular hydrogen. III. 28{endash}114-keV He{sup +}+H{sub 2}
- Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588-0111 (United States)
Absolute cross sections, differential in energy and angle of ejection of the secondary electrons, were determined for electron emission from He{sup +}+H{sub 2} collisions at 28{endash}114 keV by measuring electron energy spectra from 1.5 to 300 eV at several angles from 15{degree} to 160{degree}. A rotatable electrostatic analyzer was used with an energy resolution of 5{percent} and an angular acceptance of 4.6{degree} full width at half maximum. The double-differential cross sections were integrated over angle, energy, or both to obtain single-differential and total ionization cross sections. The latter are in excellent agreement with previous experimental results. Agreement of the experimental double-differential cross sections with plane-wave Born approximation calculations is generally poor. The cross section for ejection of high-energy electrons by He{sup +} is considerably larger than that for H{sup +} at the same velocity. This is attributed mostly to electron emission from the projectile. The presence of prominent Doppler-shifted helium autoionization peaks in the spectra indicates an appreciable probability for electron capture by the helium ions with simultaneous double excitation. {copyright} {ital 1996 The American Physical Society.}
- OSTI ID:
- 277302
- Journal Information:
- Physical Review A, Vol. 53, Issue 1; Other Information: PBD: Jan 1996
- Country of Publication:
- United States
- Language:
- English
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