PHYS 32 |
| The X+CH4 (X=O,H,Cl,F) reactions have been investigated using different levels of the chemical reaction theory. The potential-energy surfaces have been characterized using high-accuracy electronic-structure calculations, including CCSD(T) with extrapolations to the complete basis set. This high-quality ab initio information has been employed to improve the accuracy of standard semiempirical Hamiltonians by deriving new parameters specific to each reaction. The specific-reaction-parameters (SRP) semiempirical Hamiltonians accurately match the high-quality ab initio data, but are orders of magnitude faster. Using these SRP Hamiltonians, we have carried out quasiclassical-trajectory calculations of the reactions' dynamics. The results of our dynamics calculations, including product-state distributions, angular distributions, and excitation functions, are often in excellent agreement with experiments, and usually improve over other calculations. We conclude that SRP Hamiltonians have an excellent potential to provide accurate potential-energy surfaces for reactions of arbitrary dimensionality, thereby enabling reaction-dynamics calculations of large systems, which have been prohibitive until now. |
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Electronic Structure and Reaction Dynamics of Open-shell Species
8:00 AM-12:05 PM, Sunday, April 6, 2008 Morial Convention Center -- Rm. 345, Oral
Division of Physical Chemistry |