Summary The ratc coefficient for the reaction of CH with D2 decreases from 298 to I260 K. A pressure dependence study showed the CH disappcarancc rate to be invariant with total pressure at room temperature. Isotope exchange ptovides near thermoneutral product pathways for loss of CH following formation of a CHDJ complex. The CH disappearance rate is therefore directly proportional to the association rate to form CHD,+. The observed ...