CLASSICAL DYNAMICS STUDY OF UNIMOLECULAR DISSOCIATION OF HEXAHYDRO-1,3,5-TRINITRO-1,3,5-TRIAZINE (RDX)

The unimolecular dissociation of gas-phase hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) molecule has been investigated by using classical trajectories. A model potential energy surface was constructed to approximately reproduce known features of RDX. Dissociation was assumed to occur by simple N-N bond rupture and concerted triple-bond fission, the principal primary dissociation channels identified in the molecular beam infrared multiphoton dissociation (IRMPD) experiments by Zhao, Hintsa, and Lee [J. Chem. Phys. 1988, 88, 801]. Dissociation rate coefficients, branching ratios, and rotational, vibrational, and translational energy distributions of the products have been determined as a function of ensemble energy for a potential energy surface having barriers of 38.3 and 47.8 kcal/mol to symmetric ring dissociation and N-N bond fission, respectively. Calculated branching ratios and product-energy distributions are found to be in reasonable agreement with the experimental values.