Formation of H(2s) atoms by excitation in 10 - 100 keV collisions
- 28 March 1996
- journal article
- Published by IOP Publishing in Journal of Physics B: Atomic, Molecular and Optical Physics
- Vol. 29 (6), 1219-1224
- https://doi.org/10.1088/0953-4075/29/6/018
Abstract
Cross sections for 2s excitation of H atoms in 10 - 100 keV collisions have been determined using a modulated crossed-beam technique. The measurements have been based on observations of the Lyman alpha radiation emitted during electric-field-induced decay of the metastable H(2s) collision products. The results extend the range of the 5 - 26 keV cross sections measured by Morgan and co-workers to intermediate energies where theoretical predictions based on close-coupling methods are known to be strongly dependent on the choice of the expansion basis. The present cross sections pass through a broad maximum at about 40 keV. Over the range 5 - 100 keV the available experimental data exhibit an undulatory structure similar to that predicted by some close-coupling calculations but good quantitative agreement is very limited. Close-coupling calculations which employ large basis sets and include a large number of projectile states at the expense of target states are shown to agree less satisfactorily with experiment than those which include only the dominant 1s capture projectile channel.Keywords
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