Partitioning of excess energy in dissociative resonance capture processes

Abstract

The translational energies of selected negative ions formed by dissociative resonance capture processes from the polyatomic systems NF₃, BF₃, CF₄, C₂F₆, C₃F₈, and c‐C₄F₈ have been measured as functions of excess energy over the resonances. The excess energy in the molecular negative ion intermediate prior to dissociation has been calculated and partitioned into translational, vibrational, and, in some cases, electronic excitation of the dissociation products. The degree of vibrational activation in the intermediate state before dissociation is found to depend on the particular molecule under investigation and to vary from one dissociation channel to another. These observations are discussed in relation to theoretical concepts of dissociative resonance capture and given a qualitative explanation. The measurement of translational energy has led to a more complete interpretation of the states involved in the various processes and in computing ground state thermochemical properties of the decomposition products.