Near-threshold ionization of He and H-2 by positron impact

被引：58
|
作者：
Ashley, P
Moxom, J
Laricchia, G
机构：
[1] Department of Physics and Astronomy, University College London, London, WC1E 6BT, Gower Street
来源：
PHYSICAL REVIEW LETTERS | 1996年 / 77卷 / 07期
关键词：
D O I：
10.1103/PhysRevLett.77.1250
中图分类号：
O4 [物理学];
学科分类号：
0702 ;
摘要：
The single ionization cross sections for He and H-2 by positron impact have been measured in the first few eV above threshold and found to exhibit a different energy dependence from the corresponding electron results. If the data, between 1 and 3 eV above threshold, are fitted by a power law, exponents of 1.99 +/- 0.19 and 1.70 +/- 0.11 are obtained for He and H-2, respectively. This agrees qualitatively with extensions of the Wannier theory in that the exponent is larger than for electron impact. The quantitative disagreement with the predicted value of 2.65 might indicate that the range of validity of this theory is smaller than expected.
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页码：1250 / 1253
页数：4
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