TEMPERATURE DEPENDENCE OF DISSOCIATIVE ELECTRON ATTACHMENT TO 2-CHLOROTOLUEN, 3-CHLOROTOLUEN AND 4- CHLOROTOLUEN

Dissociative electron attachment (DEA) to 2-chlorotoluen, 3-chlorotoluen and 3-chlorotoluen is studied in a crossed electron/molecular beams experiment in the electron energy range between about 0 and 2eV and in the gas temperature range from 392K to 513K. For all three molecules the fragment anion Cl− is formed. The ion yields of Cl− shows a pronounced negative temperature effect when the gas temperature is raised from 392K to 513K. It is assumed that the reaction proceeds in two stages, the formation of an intermediate, followed by the unimolecular decay of that intermediate. The assumption is made that the longer the lifetime of the intermediate, the higher the probability of its dissociation into the observed products.