Potential energy surface, Integral cross section and rate coefficients for collisions of [formula omitted] with He

Abstract

We present a two-dimensional potential energy surface for the C4H−(X1Σ+)−He system, calculated with the internuclear C4H− distances frozen at the experimental minimum energy. Computations are carried out at the CCSD(T)-F12a level of theory with a aug-cc-pVTZ basis set. This potential surface presents a well depth of about −78.24cm−1 below the C4H−−He dissociation limit. The cross sections are obtained in the close coupling scheme and rate coefficients inferred by averaging the cross sections over a Maxwell–Boltzmann velocity distribution. A propensity towards Δj=1 transitions is observed.