communication: Observation of the Nucleophilic Displacement (S_N2) Reaction F~- + CH_3Br→CH_3f + Br~- Induced by Dissociative Electron capture in Binary Van der Waals Clusters

摘要

We report on the S_N2 reaction F~- + CH_3Br→FCH_3 + Br~- in binary clusters composed of CH_3Br and C_2F_6 in a crossed electron. molecular beam experiment. The reaction is induced by resonance dissociative electron attachment to the C_2F_6 component where the nucleophile F~- is generated at en energy (around 3.8 eV) where CH_3Br does not cap- ture electrons to form Br~-. The results indicate that the cross section for the S_N2 reaction is independent of the total excess energy which can be varied between 1.7 and 5 eV in the present system.