Monte Carlo Trajectory Calculations of the Dissociation of HCl in Ar

The modified phase-space theory of reaction rates is applied to the dissociation of HCl in a heat bath of argon atoms, Excellent agreement is obtained between the theoretical predictions and the shock-tube measurements of the dissociation rate coefficient over the temperature range 2500-5000 K. The recrossing correction factor and nonequilibrium correction factor are obtained from Monte Carlo trajectory calculations for states near the dissociation limit. The trajectories were sampled within the reaction zone, with a weight proportional to the equilibrium reaction rate. Important features of collisions of highly asymmetric diatomic molecules are discussed, and several typical reactive trajectories are shown to illustrate the importance of rotational motion in such collisions.