Speaker
Description
In the last years, several C-bearing and (C,N)-bearing chains of molecular anions have been detected in the interestellar medium (ISM). Since experimental treatments are still challenging, computational methods have to be used to understand their chemistry. The C$_5$N$^-$ anion is one of the largest (C,N)-bearing chains and, although there are several theoretical studies [1-3] that describe the dynamics of the smaller (CN$^-$,C$_3$N$^-$) + He/H$_2$ systems, for the moment there has been no study reported for the collision between this molecular anion with He or H$_2$.
We have performed quantum scattering calculations using a new ab initio potential energy surface (PES) where the interaction potential between C$_5$N$^-$ and He was obtained using CCSD(T) approach and the complete basis set (CBS) limit (see Figure 1). Given the ISM conditions of this system, we calculate the state-to-state (de-)excitation cross sections and the respective rate coefficients as a function of temperature. These results have been also compared by those obtained for the C$_3$N$^-$/C$_5$N$^-$ + H$_2$ system.
