A theory is described for the variation in the rate constants for formation of different ozone isotopomers from oxygen atoms and molecules at low pressures. The theory is implemented using a simplified description which treats the transition state as loose. The two principal features of the theory are a phase space partitioning of the transition states of the two exit channels after formation o...

Understanding intramolecular energy flow in molecules is one of the central goals of chemical physics. Statistical theories [such as Rice-Ramsperger-Kassel-MarCus (RRKM) theory] of unimolecular reaction rates, which assume that the vibrational degrees of freedom rapidly exchange energy, have proved extremely successful (1). Recent work on small molecules has provided rigorous tests of these the...

The major tropospheric removal process for hexafluorobenzene is its oxidation by hydroxyl (OH) radicals. However, there is no information on the reaction mechanism of this important process. All geometries and energies significant for the tropospheric degradation of hexafluorobenzene were characterized using the MP2/6-311+G(d,p) and/or G3 methods. It was found out that the addition of OH radica...

A model is proposed for studying the reaction dynamics in complex quantum systems which complete mixing of states hindered by an internal barrier. Such are often treated transition-state theory, also known chemistry as RRKM but validity theory questionable when there no identifiable coordinate associated with The consists two Gaussian Orthogonal Ensembles (GOE) levels coupled to each other and ...

We report the study of the isomeric selective OH-initiated oxidation of 1,3-butadiene in the presence of O2 and NO using the LP/LIF technique. The photolysis of monodeuterated 1-iodo-3-buten-2-ol provides only one of the possible OD-butadiene adducts, the minor addition channel product, simplifying the oxidation mechanism. We find, based on analysis of OD time-dependent traces that prompt rearr...

Ab-initio methods were carried out to calculate forward and reverse rate constant data for the following reactions: HgþCl22HgCl2, HgClþCl2HgCl2, HgþO2HgO, and SeþH22SeH2. Theoretical predictions of bond distances, vibrational frequencies and enthalpies of reaction are compared to available experimental data to determine the level of theory most appropriate for predicting kinetic parameters. The...

Gao and Marcus (1) presented a modified Rice, Ramsperger, Kassel, Marcus (RRKM)– based theory to explain the strange and unconventional ozone isotope effect that has puzzled scientists for years. In earlier studies, mass spectrometric (2, 3) and diode laser (4) measurements of ozone isotopomers in “scrambled” oxygen mixtures pointed toward a symmetry origin for isotope fractionation. Kinetic st...

The cyclopentadienyl radical decomposition has been studied in detail by high-level correlation MO methods combined with multichannel RRKM rate constant calculations. The product channels of the reaction were examined by calculating their pressure-dependent branching rate constants. The overall reaction rate has been shown to be controlled by the first transition state corresponding to 1,2-hydr...