Modeling Rotational State Changes in C3N− and CN− by Collision with H in Interstellar Environments

Abstract

[EN]The anions CN− and C3N−, both as electronic states, are among the oldest of the (C,N)-bearing linear anions discovered in the dark cloud core, TMC-1, more than 15 years ago by now. They are also interesting species to be studied in cold trap conditions that can mimick those temperature ranges that are dominant in the astrophysical environments. The Hydrogen atoms and molecules are the most abundant neutral species in those same environments and therefore it is important to be able to have reliable information on their collision efficiency in driving the previous anions to different populations of their internal rotational states. In the present study we devise a way of focusing the ab initio calculations of the anions’ interactions with H atoms to primarily the inelastic, energy-transfer channels and therefore are able to generate the corresponding rotationally inelastic rate coefficients at the temperatures between 10K and 220K. The results from such findings could help us to clarify possible experimental data in traps and also allow us to establish the substantial efficiency of this atomic partner in causing collision-driven rotational state changes at low temperatures for the present anions of the ISM environments.