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Relative and absolute level populations in beam-foil-excited neutral heliumRelative and absolute populations of 19 levels in beam-foil-excited neutral helium at 0.275 MeV have been measured. The singlet angular-momentum sequences show dependences on principal quantum number consistent with n to the -3rd power, but the triplet sequences do not. Singlet and triplet angular-momentum sequences show similar dependences on level excitation energy. Excitation functions for six representative levels were measured in the range from 0.160 to 0.500 MeV. The absolute level populations increase with energy, whereas the neutral fraction of the beam decreases with energy. Further, the P angular-momentum levels are found to be overpopulated with respect to the S and D levels. The overpopulation decreases with increasing principal quantum number.
Document ID
19760027761
Document Type
Reprint (Version printed in journal)
Authors
Davidson, J. (Arizona, University Tucson, Ariz., United States)
Date Acquired
August 8, 2013
Publication Date
October 1, 1975
Publication Information
Publication: Physical Review A - General Physics
Subject Category
ATOMIC AND MOLECULAR PHYSICS
Distribution Limits
Public
Copyright
Other