15min:

K. FUKUZAWA AND Y. OSAMURA, Department of Chemistry, Faculty of Science, Rikkyo University, 3-34-1 Nishi-ikebukuro, Toshima-ku, Tokyo 171, Japan; H. F. SCHAEFER III, Center for Computational Quantum Chemistry, University of Georgia, Athens, GA 30602, USA.

The dissociative recombination reaction between HC₃NH⁺ and an electron is one of the major route to produce cyanoacetylene, HC₃N, in interstellar clouds. We have studied various pathways of this recombination reaction producing HC₃N and its isomers, HNC₃, HCCNC, and HCNCC, theoretically. Potential energy surfaces for the processes from neutralized HC₃NH are examined by using the ab initio\/ molecular orbital method. The calculated result shows that HCCNC is also produced via the isomerization processes in addition to the products HC₃N and HNCCC from the direct hydrogen dissociation. Several product channels C₂H + HNC, C₂H + HCN, NH + C₃H, CN + C₂H₂, C₃ + NH₂ and C₃N + H₂ are shown to be energetically possible based on the thermochemical relationships.