Recombination of silicon ions by electron capture from atomic hydrogen and helium

 Ab initio potential-energy curves and coupling matrix elements of the Σ and Π molecular states involved in the collision of the Si2+, Si3+ and Si4+ multicharged ions on atomic hydrogen and helium have been determined by means of configuration interaction methods. The total and partial electron capture cross sections have been determined using a semiclassical or a quantal approach in the 0.002–0.1 au velocity range. A detailed comparison with very recent theoretical and experimental rate coefficient results is made.