Differential cross sections for the electron impact excitation of n3,1S (n=2, 3 and 4) states of helium at low energies
- 28 April 1994
- journal article
- Published by IOP Publishing in Journal of Physics B: Atomic, Molecular and Optical Physics
- Vol. 27 (8) , 1561-1575
- https://doi.org/10.1088/0953-4075/27/8/016
Abstract
The 19-state and the 29-state R-matrix calculations are employed to obtain the differential cross sections for the 11S-n3,1S (n=2, 3 and 4) excitation of helium at carefully chosen non-resonance energies ranging from 22 to 29.6 eV. The scattering angle ranges from 0 degrees to 180 degrees . The results of the calculation are compared with the latest experiments of Trajmar et al. (1992) and Allan (1992). Attempts are made to show that the angular distributions of scattered electrons of the same incident velocity that have excited the n3S (or n1S) levels of helium for n=2, 3 and 4 are almost identical when fitted together at one angle.Keywords
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