Experiments on electric-field anticrossings of He I levels excited by He-He collisions
- 14 February 1993
- journal article
- Published by IOP Publishing in Journal of Physics B: Atomic, Molecular and Optical Physics
- Vol. 26 (3) , 381-392
- https://doi.org/10.1088/0953-4075/26/3/011
Abstract
Electric-field anticrossings of 1snl 1 Lambda and 3 Lambda Stark levels of He I with n=4 to 7, l=2 to 5 and Lambda = mod ML mod <or=2 are investigated experimentally using 12 keV He-He collisions for excitation. For supplementary measurements also Ne atoms were used as projectiles. The measured electric-field positions of the anticrossing signals are in accord with calculated values. The dependence of the signal amplitudes on the polarization of the detected impact radiation is investigated. These measurements corroborate the identification of the signals. Some signal amplitudes are strongly affected by weak magnetic fields. Most anticrossing signals are Lorentz-shaped. However, significant deviations from the Lorentz shape are found for the anticrossings of the 1s4d configuration. These deviations are caused by the high-velocity He atoms used as projectiles. The findings are discussed and compared with theoretical results.Keywords
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