A workflow for automatic generation and efficient refinement of individual pressure-dependent networks

Manual chemical kinetic model construction often requires modelists to at least implicitly guess all possible decay pathways and their relative fluxes for all important species. We present a workflow and associated tool for automatic generation and refinement of pressure-dependent networks (multiwell potential energy surfaces) that should enable modelists to efficiently and comprehensively identify decay pathways and estimate respective parameters for chemical species. This tool within the Arkane software combines the capabilities of the Reaction Mechanism Generator (RMG) software to generate possible reaction paths, determine thermochemistry, approximate rate coefficients and estimate frequencies with the capabilities of Arkane to use quantum chemical parameters to compute thermochemistry and pressure-dependent rate coefficients. A flux-based algorithm is used to decide which isomers to add to the network. Isomers added to the network are reacted to form other channels. When enough of the flux is accounted for by the isomers and bimolecular product channels, the generation process terminates to yield a comprehensive network. Network sensitivity analysis is applied to identify the most important wells and barriers that can be refined using quantum chemistry calculations. Iterative refinement can then be used to achieve accuracy. The comprehensive network can be easily reduced using energy and flux-based algorithms to the most important channels and isomers. (c) 2022 The Combustion Institute. Published by Elsevier Inc. All rights reserved.