Recombination of silicon ions by electron capture from atomic hydrogen andhelium

Ab initio potential-energy curves and coupling matrix elements of the Sigma and Pi molecular states involved in the collision of the Si2+, Si3+ and Si 3+ 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 quan tal approach in the 0.002-0.1 au velocity ran Re. A detailed comparison wit h very recent theoretical and experimental rate coefficient res;lts is made .