Electron capture in H+ + S(3P,1D) collisions is studied theoretically by using a semiclassical molecular representation with five molecular channels from the initial ground and excited states at collision energies above 10 eV. Electron capture in S+ (4S)+ H(1 s) collisions is also investigated by using three molecular channels in order to assess the earlier estimation which gave the rate constant of 10-15 cm3/s at 104 K for the process. The ab initio potential curves and nonadiabatic coupling matrix elements for the HS+ system are obtained from multireference single- and double-excitation configuration-interaction calculations employing relatively large basis sets. Dominant capture channels corresponding to the [H + S+(2P)] and [H+S+(2D)] states lie lower by 0.2 and 1.4 eV, and 1.34 and 2.5 eV from the initial ground [H++S(3P)] and excited [H++S(1D)] states, respectively. The present results show that electron capture from the excited species is found to be rather weak at lower energies. But it rapidly becomes comparable to that from the ground state. Electron capture in S+ (4S) + H collisions proceeds through the two-step mechanism at lower energies, and therefore, the cross section is found to be small with the value less than 10-17 cm2 below 1 keV, thus supporting the earlier estimation.
|Number of pages||5|
|Journal||Physical Review A - Atomic, Molecular, and Optical Physics|
|Publication status||Published - 1997|
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Atomic and Molecular Physics, and Optics