Rotational excitation of methylidynium (CH+) by a helium atom at high temperature

TL;DR

This paper calculates high-temperature collisional excitation rate coefficients for CH+ by helium using ab initio methods, providing data crucial for astrophysical modeling of interstellar environments.

Contribution

The study introduces accurate rate coefficients for CH+ excitation by He at high temperatures using coupled-cluster calculations and close coupling methods.

Findings

Rate coefficients computed up to 2000 K

Interaction potential energy obtained via CCSD(T)

Cross sections calculated for J=0 to 10

Abstract

We aim to obtain accurate rate coefficients for the collisional excitation of CH+ by He for high gas temperatures. The ab initio coupled-cluster [CCSD(T)] approximation was used to compute the interaction potential energy. Cross sections are then derived in the close coupling (CC) approach and rate coefficients inferred by averaging these cross sections over a Maxwell-Boltzmann distribution of kinetic energies. Cross sections are calculated up to 10'000 cm^-1 for J ranging from 0 to 10. Rate coefficients are obtained at high temperatures up to 2000 K.