Influence of the autoionising states on the linear polarisation of helium lines excited by electrons with energy between 56 and 64 eV
- 28 March 1980
- journal article
- Published by IOP Publishing in Journal of Physics B: Atomic and Molecular Physics
- Vol. 13 (6) , 1229-1248
- https://doi.org/10.1088/0022-3700/13/6/027
Abstract
Data are presented for the linear polarisation of helium lines excited by electron impact in the energy range corresponding to the He- resonances lying near the thresholds of the first doubly excited states. These autoionising He- states are observed as resonance structures in the polarisation. Within the experimental uncertainties these structures correspond to a maximum polarisation effect in the emitted light. Correlated to this is the change of angular momentum with respect to the direction of the bombarding electron beam which is a minimum for the particles concerned with the resonant process. Post collisional interaction, associated with the neutral doubly excited states, give no or weak structures in the polarisation.Keywords
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