Journal of Physical Chemistry A, Vol.106, No.36, 8339-8344, 2002
Relationship between mode specific and thermal unimolecular rate constants for HOCl -> OH+Cl dissociation
Recent quantum dynamical calculations [Hauschildt, J.; et al. Chem. Phys.. Lett. 1999, 300, 569] have shown that HOCl --> OH + Cl dissociation on the ground-state potential energy surface, and for J = 0, occurs predominantly via isolated compound-state resonances, whose rates are highly mode-specific. In this work, these resonance rates are averaged to calculate the HOCl --> OH + Cl unimolecular rate constant as a function of temperature and pressure. The result is compared with the standard pressure and temperature dependent RRKM unimolecular rate constant. It is found that the state-specificity makes the pressure-dependent rates significantly lower than the RRKM rates in the intermediate pressure regime.