Electron transfer reactions from OCS to H₂^+·

The dissociative charge-transfer reactions of H₂^+· with OCS were studied, and the product branching ratios measured for H₂^+· beam energies variable in the range 1200-5000 eV. These experimental data were interpreted quantitatively in terms of the modified Stückelberg-Demkov mechanism for the non-crossing of reactant and product potential energy curves. The experimental results are accurately modelled when cognizance is taken of the short time of collision (ca. 10^-14 s) and the minimum impact parameter for a particular reaction. The short reaction time means that rotation of the collision partners can be ignored and hence the geometry of the collision has to be considered. Once this geometry has been specified, it will define the minimum critical radius (R_c) which is acceptable for that given type of collision. Most of the charge-transfer reactions occurred with R_c in the range 3-5 Å. The experimental results could not be reproduced by a curve-crossing mechanism of the Landau-Zener type. © 1986.