Coupled states distorted wave study of the O(/sup 3/P)+H/sub 2/ (D/sub 2/, HD, DH) reaction
In this paper, the coupled states distorted wave (CSDW) method is used to study the quantum reactive collision dynamics of O(/sup 3/P)+H/sub 2/ ..-->.. OH+H and its D/sub 2/, HD, and DH counterparts. The potential surface used is the sum of a LEPS potential (due to Johnson and Winter) and a correction factor which raises the barrier for H+OH ..-->.. HO+H exchange to a realistic value. Full basis set convergence of the CSDW transition probabilities is established at low energies where tunneling dominates the dynamics, which means that the calculated cross sections should be exact except for errors introduced by the CS approximation, and the latter are expected to be less than 30%. The results presented for all four isotopes include: reaction probabilities as a function of energy E and total angular momentum J, total and state to state integral cross sections (including an analysis of product state distributions), and thermal and state resolved rate constants. Comparison of the results with those of several previous dynamical calculations on the same or similar surfaces is made and the accuracy of the approximations made in those calculations is assessed. For example, the product rotational distributions predicted by vibrationally adiabatic distorted wave theory are found to be quite close to what we calculate, although the absolute magnitudes of the cross sections are quite different. Comparison with the results of quasiclassical trajectory calculations indicates good agreement of the reactive cross sections well above the classical threshold, but not of the rate constants (because of tunneling) or of isotope ratios. Wigner corrected conventional transition state theory is very inaccurate in predicting rate constants, but a method which uses collinear exact quantum (CEQ) transmission coefficients to correct transition state theory does quite well.
- Research Organization:
- Theoretical Chemistry Group, Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
- OSTI ID:
- 6214948
- Journal Information:
- J. Chem. Phys.; (United States), Vol. 83:11
- Country of Publication:
- United States
- Language:
- English
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ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
HYDROGEN
CHEMICAL REACTION KINETICS
OXYGEN
ATOM-MOLECULE COLLISIONS
CHEMICAL REACTIONS
DEUTERIUM
ISOTOPE EFFECTS
ATOM COLLISIONS
COLLISIONS
ELEMENTS
HYDROGEN ISOTOPES
ISOTOPES
KINETICS
LIGHT NUCLEI
MOLECULE COLLISIONS
NONMETALS
NUCLEI
ODD-ODD NUCLEI
REACTION KINETICS
STABLE ISOTOPES
400201* - Chemical & Physicochemical Properties