Design and implementation of a next-generation software interface for on-the-fly quantum and force field calculations in automated reaction mechanism generation

A software interface for performing on-the-fly quantum and force field calculations has been developed and integrated into RMG, an open-source reaction mechanism generation software package, to provide needed estimates of thermodynamic parameters. These estimates based on three-dimensional molecular geometries bypasses the traditional group-additivity-based approach, which can suffer from lack of availability of necessary parameters; this issue is particularly evident for polycyclic species with fused rings, which would require ad hoc ring corrections in the group-additivity framework. In addition to making extensive use of open-source tools, the interface takes advantage of recent developments from several fields, including three-dimensional geometry embedding, force fields, and chemical structure representation, along with enhanced robustness of quantum chemistry codes. The effectiveness of the new approach is demonstrated for a computer-constructed model of combustion of the synthetic jet fuel JP-10. The interface also establishes a framework for future improvements in the chemical fidelity of computer-generated kinetic models.

► RMG is an open-source automated reaction mechanism generation tool.
► An interface was developed to incorporate 3D molecular structures into RMG.
► The interface improves reliability of thermodynamic estimates for polycyclic species.
► The interface creates opportunities for improvement in other areas.