A MOLECULAR ORBITAL STUDY OF THE HC3NH+ + e- DISSOCIATIVE RECOMBINATION AND ITS ROLE IN THE PRODUCTION OF CYANOACETYLENE ISOMERS IN INTERSTELLAR CLOUDS

摘要

The dissociative recombination reaction between HC3NH+ and electrons is an important process in the chemistry of interstellar clouds. Motivated by the evidence that HCN and its metastable isomer HNC are both formed via the dissociative recombination reaction of HCNH+ ,We have examined the potential energy surface for the dissociation of the transient HC3NH following the recombination between HC3NH+ and e1ectrons. We find that HC3NH+ gains l5l kcal mol-1 energe by the neutral- ization; this energy is high enough to isomerize HC3NH to HCCNCH, as well as to dissociate a hydro- gen atom from either end of the molecule. The present calculation suggests, therefore, that the metastable linear and near-1inear isomers of HC3N, namely, HNC3, HCCNC, and HCNCC, can be formed via the dissociative recombination between HC,NH+ and electrons.