Electron capture and He+(2s) formation in fast He2+-H and He+-H collisions

Cross sections for the accidentally resonant charge-transfer process He 2+ +H(1s) to He + (2s)+H + and total cross sections for the process He 2+ +H(1s) to He + ( Sigma n,l)+H + involving capture into all final bound states of He + have been measured for 4-343 keV 3 He 2+ ions. A tungsten tube furnace was used to provide a target of highly dissociated hydrogen. The results greatly extend the energy range of previous measurements and provide data of increased accuracy thereby permitting a better assessment of the range of validity of theoretical descriptions of He 2+ -H collisions. Corresponding cross sections for capture in H 2 have also been determined. Cross sections for the direct excitation process He + (1s)+H to He + (2s)+H( Sigma ) have also been measured for the first time within the same energy range.