Theoretical treatment of state-selective one-electron capture by S3+ ions in collisions with helium

Ab-initio potential energy curves and coupling matrix elements of the molecular states involved in the collision of the S3+ multicharged ion on helium have been determined by means of configuration interaction methods. The total and partial electron capture cross sections for the S3+/He system have been determined using a semi-classical method in the 2-50 keV laboratory energy range. The results show a decrease of the cross section on the S2+(D-1) level for increasing collisional energy, in good agreement with experimental data. (C) 1998 Elsevier Science B.V.