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Accession Number DE2012-1045378
Title Theoretical Chemical Dynamics Studies of Elementary Combustion Reactions.
Publication Date Sep 2009
Media Count 4p
Personal Author D. L. Thompson
Abstract The objective of this research was to develop and apply methods for more accurate predictions of reaction rates based on high-level quantum chemistry. We have developed and applied efficient, robust methods for fitting global ab initio potential energy surfaces (PESs) for both spectroscopy and dynamics calculations and for performing direct dynamics simulations. Our approach addresses the problem that high-level quantum calculations are often too costly in computer time for practical applications resulting in the use of levels of theory that are often inadequate for reactions. A critical objective was to develop practical methods that require the minimum number of electronic structure calculations for acceptable fidelity to the ab initio PES. Our method does this by a procedure that determines the optimal configurations at which ab initio points are computed, and that ensures that the final fitted PES is uniformly accurate to a prescribed tolerance. Our fitting methods can be done automatically, with little or no human intervention, and with no prior knowledge of the topology of the PES. The methods are based on local fitting schemes using interpolating moving least-squares (IMLS). IMLS has advantages over the very effective modified-Shepard methods developed by Collins and others in that higher-order polynomials can be used and does not require derivatives but can benefit from them if available.
Keywords Chemical reactions
Electronic structure
Potential energy
Reaction kinetics

Source Agency Technical Information Center Oak Ridge Tennessee
NTIS Subject Category 99F - Physical & Theoretical Chemistry
81A - Combustion & Ignition
Corporate Author Missouri Univ.-Columbia. Environmental Health Surveillance Program.
Document Type Technical report
Title Note N/A
NTIS Issue Number 1303
Contract Number DE-FG02-04ER15607

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