S-wave resonances in positron scattering by He{sup +}
- The Institute of Physical and Chemical Research (RIKEN), Wako, Saitama 351-01 (Japan)
S-wave e{sup +}+He{sup +} scattering is calculated using the hyperspherical close-coupling method. The two resonances found at about {minus}0.73 Ry and {minus}0.39 Ry by Bhatia and Drachman [Phys. Rev. A {bold 42}, 5117 (1990)] and reproduced by Ho [Phys. Rev. A {bold 53}, 3165 (1996)] do not occur in the present results. An argument against these proposed resonances is presented on the basis of the adiabatic hyperspherical potentials. Instead of these resonances, we have found narrow Feshbach resonances just below the thresholds ({minus}0.25 a.u. and {minus}0.0625 a.u.) of the formation of Ps(n=1) and Ps(n=2) and an extremely narrow shape resonance just above the threshold {minus}0.08 a.u. of He{sup +}(n=5). They would be hardly detected since (i) the resonance widths are of the order of 10{sup {minus}4}{endash}10{sup {minus}5} a.u. or less, (ii) the resonance is weak in the elastic cross section, (iii) the magnitudes of the inelastic and Ps-formation cross sections are small, and (iv) the smooth cross sections due to higher partial waves should still be added to the S-wave cross section. {copyright} {ital 1997 The American Physical Society}
- OSTI ID:
- 553066
- Journal Information:
- Physical Review A, Journal Name: Physical Review A Journal Issue: 6 Vol. 56; ISSN 1050-2947; ISSN PLRAAN
- Country of Publication:
- United States
- Language:
- English
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