Threshold Law For Positron Impact Ionization of Atoms
- Department of Mathematics, Royal Holloway, University of London, Egham, Surrey TW20 0EX (United Kingdom)
- Oak Ridge National Laboratory, P.O. Box 2009, Oak Ridge, Tennessee 37831 (United States)
We demonstrate that recent experiments for positron impact ionization of He and H{sub 2} can be interpreted by extending Wannier theory to higher energies. Anharmonicities in the expansion of the three-particle potential around the Wannier configuration give rise to corrections in the threshold behavior of the breakup cross section. These corrections are taken into account perturbatively by employing the hidden crossing theory. The resulting threshold law is {sigma}(E){proportional_to}E{sup 2.640}exp[ -0.73{radical}(E)] . The actual energy range for which the Wannier law is valid is found to be smaller for positron impact ionization than for electron impact ionization. {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 548769
- Journal Information:
- Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 21 Vol. 78; ISSN 0031-9007; ISSN PRLTAO
- Country of Publication:
- United States
- Language:
- English
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