Studies of dissociative attachment reactions: from gas phase to condensed phase

The resonance theory of dissociative electron attachment developed by O'Mal ley and Bardsley more than thirty years ago has become an efficient tool fo r ab initio calculations of dissociative attachment to diatomic molecules. We illustrate this by discussing application of non-local complex potential theory to the process of dissociative attachment to the HF molecule. For p olyatomics we have developed a semiempirical resonance method based on the one-pole approximation for the R matrix. We demonstrate results of applicat ion Of this theory to methyl halides in the gas and condensed phases. Many interesting observations, particularly a strong temperature effect for meth yl chloride, vibrational Feshbach resonances for methyl iodide, and condens ed-matter effects in dissociative atttachment to methyl- and perfluoromethy l chloride are explained by our theoretical calculations.