AN APPLICATION OF CONVENTIONAL TRANSITION-STATE THEORY TO COMPUTE HIGH-PRESSURE LIMIT THERMAL RATE COEFFICIENTS FOR THE REACTION - H(D)+O-2-REVERSIBLE-ARROW-H(D)O-2-ASTERISK-REVERSIBLE-ARROW-OH(D)+O

Several ab initio studies have focused on the minimum energy path region of the hydroperoxyl potential energy surface (PES) (J. Chem. Phys. 1988, 88, 6273) and the saddle point region for H-atom exchange via a T-shaped HO2 complex (J. Chem. Phys, 1989, 91, 2373). Further, the results of additional calculations (J. Chem, Phys. 1991, 94, 7068) have been reported which, when combined with the earlier studies, provide a global description (but not an analytic representation) of the PES for this reaction. In this work, information at the stationary points of the ab initio PES is used within the framework of conventional transition state theory (TST) applied to both unimolecular and bimolecular processes in the high-pressure limit to compute estimates of the thermal rate coefficients for the forward and reverse reactions. Because these reactions proceed via a bound complex, a simple probability model is utilized to interpret the calculated statistical rate coefficients and to compare the present calculations with both the most recent experimental measurements and the results of quasiclassical trajectory calculations completed on the (analytic) DMBE IV PES (J. Chem. Phys. 1992, 96, 5137).