QUANTUM DYNAMICS STUDY OF H-2-]HCN+H REACTION IN FULL DIMENSIONS(CN)

Time-dependent (TD) quantum dynamics calculation for the title reactio n has been carried out in full mathematical (six) dimensions on a new potential energy surface (denoted TSH3). Our numerical calculation sho ws that as far as total reaction probabilities and cross sections are concerned, the CN vibration behaves like a spectator bond when both re agents are at ground vibrational state. The vibrational excitation of CN slightly decreases the reaction probability and cross section while vibrational excitation of H-2 considerably enhances the reaction prob ability and cross section. The reaction probability is enhanced by exc itations of H-2 rotation and more so of CN rotation. Overall, the reac tion proceeds by a direct abstraction path without contribution from t he insertion process. Comparison of our calculated rate constant with experimental measurements indicates that the effective barrier of the TSH3 PES for the title reaction is perhaps too high by about 0.3 kcal/ mol. (C) 1998 American Institute of Physics. [S0021-9606(98)00409-7].