Exploration of complex reaction systems with the Chemical Trajectory analYzer (CTY) and CVHD acceleration

In this study, we investigate the acceleration of reactive molecular dynamics (rMD) simulations to explore complex chemical reaction networks. We demonstrate how identification of species and reactions is facilitated by the Chemical Trajectory analYzer (CTY) tool that simultaneously detects reaction pathways and computes rate constants. All geometries of reactants, transition states and products are saved for higher-level calculations. This automated PES mapping allows for coupling to mechanism and master equation software and studying overall ignition and combustion behavior of fuels.
We accelerate the rMD using collective-variable driven hyperdynamics (CVHD) to find the reaction networks within hours up to some days. We investigate different CVs to model dissociation, association, abstraction and substitution.
The analysis applied to C₄ hydrocarbon isomerization networks detects 44 reactions, including the identification of all important butenyl radicals and their decomposition reactions. Also, by the acceleration of CVHD, the chain branching path over ROO and QOOH at 500-1500 K and decomposition of primary ozonide at 298 K was found successfully. It gives the potential to employ this method to help reveal reaction pathways of a similar mechanism for larger molecules.