Calculations are reported at the MP2/6-311++G(2df,2pd) level of theory on the reaction of K atoms with CH3CN, with different orientations of the CH3CN molecule with respect to the incoming K atom. Approach along a minimum energy pathway does not involve a simple harpoon mechanism. Stretching of the C-C bond of CH3CN facilitates electron transfer. Electron transfer occurs on a repulsive surface for CN end approach and on an attractive surface for methyl end approach. For approach from the methyl end of the molecule, the barrier to the formation of CH2CN- is lower than that for the formation of CH3CN- or CN- as the K atom approaches closer to the CH3CN molecule. (C) 2003 Elsevier Science B.V. All rights reserved.