Reaction Rate of CH

The rate coefficient for the formation of CH by radiative association of C and H was calculated theoretically over the last several decades. The values obtained differ widely, because of a sensitive dependence on the collisions through the B 2 Σ - molecular state, which has a repulsive barrier. The barrier height calculated by quantum chemical methods varies, leading to different values of the rate coefficient. Recently, an extensive set of data on the CH molecule was published by Masseron et al. (2014). In this paper, we use predissociative and radiative lifetimes to calculate the rate coefficient to be 5 ∗ 10−19 cm3 /s at 100K with a slightly larger rate coefficient at lower T due to threshold effects with resonance. This was all measured taking this barrier into consideration and therefore the use of neutral Carbon and Hydrogen interactions in a low or mid-range temperature environment can now be modeled using a more accurate rate coefficient.Astro 9