Hyperspherical close-coupling calculations for charge transfer cross sections in Si4++H(D) and Be4++Hcollisions at low energies

Total and partial electron capture cross sections are calculated for Si4+ + H(1s)/D(1s) collisions from 1 meV amu(-1) to 1 keV amu(-1), and for Be4+ + H(1s) collisions from 2.5 eV amu(-1) up to 1 keV amu(-1) using the recently developed hyperspherical close-coupling (HSCC) approach. For both systems, our results are in good agreement with calculations based on the molecular orbital expansion method in reaction coordinates (RC). For Si4+ + D(1s) our total charge transfer cross sections agree well with experiment, but not the partial cross sections. For Be4+ + H, we show that partial wave cross sections from the RC method have more oscillatory structures than those from the HSCC method, even though the total cross sections agree. In comparison with the RC method, the HSCC approach does not require the introduction of any ad hoc external parameters in the formulation.