ECAMP 15

Several negative molecular ions have been detected in the interstellar medium CN-, C3N-, C5N-, C7N-, C4H-,C6H-,C8H-,C10H-. Since their discovery, for many years, there had been a general consensus in the community of modelers that in the interstellar medium (ISM) the ions are formed by the process of radiative electron attachment (REA). However, in several recent studies it has been shown that the REA process is too slow to explain the observed abundance of the ions in the ISM. In this study, we consider an alternative process of formation of ions: by dissociative electron attachment (DEA). First-principle calculations were performed to evaluate the cross sections and the rate coefficient for the DEA process to the HNCCC molecule, leading to formation of C3N- in the ISM. The obtained rate coefficient is large enough to explain the observed abundance of C3N- in the ISM. While no full calculations were performed for other molecular ions, observed in the ISM, it is expected that rate coefficients for their formation by similar reactions are also large enough to explain their formation in the ISM by DEA.