Low-energy electron capture by N{sup 4+} ions from H atoms: Experimental study using merged beams and theoretical analysis by molecular representation
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6372 (United States)
- Argonne National Laboratory, Argonne, Illinois 60439 (United States)
Measurements and theoretical analyses of total electron-capture cross sections for collisions of N{sup 4+} with ground-state hydrogen (deuterium) are reported in the energy range 1--300 eV/u. The present measurements have reduced relative uncertainty compared to previous absolute measurements at Oak Ridge National Laboratory [Huq {ital et} {ital al}., Phys. Rev. A 40, 1811 (1989)] and are used for detailed comparison with more recent coupled-channel molecular-orbital calculations [Shimakura {ital et} {ital al}., Phys. Rev. A 45, 267 (1992); Zygelman {ital et} {ital al}., {ital ibid}. 46, 3846 (1992)]. The most striking difference between the calculations was the increasing trend in the cross section for collision energies below 4 eV/u, as estimated by Zygelman {ital et} {ital al}. using only singlet states of the quasimolecule and the decreasing trend predicted by Shimakura {ital et} {ital al}. using both singlet and triplet states. The latter decreasing trend is consistent with the previous measurement. At 0.5 eV/u, the predicted singlet cross sections differ nearly by a factor of 2. Possible origins for this difference are explored. Strong structure is predicted in the cross section of Zygelman {ital et} {ital al}. and, to a lesser extent, in that of Shimakura {ital et} {ital al}. ; however, the phase of the structure is different in the two theories. Structures observed in the measurement at the higher collision energies are not in complete harmony with either prediction.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- DOE Contract Number:
- AC05-84OR21400; W-31109-ENG-38; AC05-76OR00033
- OSTI ID:
- 46371
- Journal Information:
- Physical Review A, Vol. 51, Issue 5; Other Information: PBD: May 1995
- Country of Publication:
- United States
- Language:
- English
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