A comparative study of the DR reactions of c-C3H+3 and l-C3H+3: Preliminary theoretical studies

Preliminary calculations related to the dissociative recombination (DR) of electrons with C3H+3 have been carried out. Both the linear and cyclic isomers of this ion exist in the interstellar medium, and accurate DR rate constants for both isomers are needed for astrophysical models. The electronic structure calculations reported here yield quasi-diabatic potential energy curves that can be used to assess the efficiency of dissociation of a CH bond. The calculations confirm a favorable position of a dissociative state for the cyclic isomer and suggest that dissociation of the linear isomer is less probable. More detailed dynamical studies are planned, and a normal mode analysis of the vibrational modes of C3H+3 is reported as the first step in that direction.