Automated theoretical chemical kinetics: Predicting the kinetics for the initial stages of pyrolysis

Large scale implementation of high level computational theoretical chemical kinetics offers the prospect for dramatically improving fidelity combustion modeling. To facilitate such efforts, we have developed a suite codes, collectively referred to as AutoMech, that allow automatic prediction large sets reactions via ab initio transition-state-theory based master-equation calculations. The primary input is simply mechanism, dictionary relating chemically identifiable species descriptors (e.g., SMILES or InChIs) labels in and specification electronic structure transition state theory models be implemented. Here illustrate current utility AutoMech through study initial stages pyrolysis 3 fuels: sequences alkanes, alcohols, aldehydes. For simplicity, analysis focuses on abstractions from fuel by H, CH3, OH, decomposition resulting radicals. Altogether, there are total 166 channels these (more than 363 forward when expanded full set elementary reactions). code successfully produces quality rate estimates (with apparent uncertainties less factor two limited comparisons with experiment) >95% these. radical reactions, includes predictions pressure dependence kinetics. This wide-ranging exploration illustrates (i) effect different levels expected accuracy, (ii) branching between at sites abstractors, (iii) rates structure, (iv) variation stabilities across families. These results, well demonstrated feasibility methodology, should find further development accurate expressions arbitrary fuels.