Charge exchange in collisions of 1–100-keV Sn3+ ions with H2 and D2

Absolute cross sections for single electron capture by Sn3+ colliding with H2 and D2 have been measured and calculated in the energy range of 1 – 100 keV. The cross sections are determined by measuring the change in ion beam current with varying target density and by measuring the yields of charged target fragments by means of a time-of-flight spectrometer. The results for D2 show good agreement with our seven-state semi-classical calculations, while for H2 the experimental results increase more strongly than the calculations towards lower energies. This discrepancy is attributed to vibrational effects, not included in the calculations, that lead to the breakdown of the Franck-Condon approximation.