Electron-capture dynamics in collisions of Si4 ions with He atoms at intermediate energies -: art. no. 042717

Electron capture resulting from collisions of Si4+ ions with He atoms below 25 keV/u is investigated using a molecular-orbital representation within both the semiclassical and quantal representations. Nine molecular states connectings both to single and double electron-capture processes are included, and hence radial and rotational couplings among these channels are fully considered. Electronic stares and corresponding couplings are determined by the multireference single- and double-excitation configuration interaction method. The present results tie in well with the earlier calculations of Stancil et al. at lower energies, but show a rather different magnitude from the theoretical results of Bacchus-Montabonel and Ceyzeriat and are somewhat smaller than the measurements of Tawara et al. The present rate constants do not support the experimental finding of Fang and Kwong at 4,600 K.