The influence of negative ion resonances on the electron impact excitation of the 33D state of helium near 60 eV
- 28 December 1991
- journal article
- Published by IOP Publishing in Journal of Physics B: Atomic, Molecular and Optical Physics
- Vol. 24 (24) , 5151-5167
- https://doi.org/10.1088/0953-4075/24/24/013
Abstract
The authors have studied the electron impact excitation of the 33D state of helium at incident energies near the well known negative ion resonances He-(2s2 2p) 2P and He-(2s2p2) 2D at 57.2 and 58.3 eV respectively. This was done by measuring the polarization degree of the radiation emitted in the subsequent 33D to 23P transition both in a non-coincidence and a coincidence experiment. As the direct excitation process of 33D and the indirect excitation process via a negative ion resonance are indistinguishable, these processes interfere. Analysis of the present and previous results indicate that the effects of interference play a minor role for the polarization degree as measured in the non-coincidence experiment. For the coincidence experiment the effects of interference are important.Keywords
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