Molecular mechanics (MM) force fields are atomistic models used in many areas of chemistry. Canonical approaches to extend either the chemical space coverage and accuracy of a given force field requires significant manual effort to parametrize and fit which is accompanied by difficulties in finding a metric to fit too. This work iterates on these problems with a focus on torsion parameters, a traditionally difficult aspect of force field parameterization. The torsion energy term describes the energy of a molecule as it rotates around its bonds and is commonly given as a sum of cosine terms with periodicities that are chosen using chemical expertise.<br/>To automate and generalize the process, several problems need to be addressed. These are: 1) intelligent fragmentation of compounds for Quantum Chemistry (QC) calculations to reduce misrepresentation of the chemical environment of the torsion, 2) automation of many QC torsion scans, 3) automated parameter fitting and model selection, and 4) finding the correct granularity of chemical environments for transferable torsion types. This talk focuses on the open-source and modular software developed to solve these problems and is focused on both the future sustainability and the general CMS communities' needs in mind. The QC calculations are captured, indexed with several canonical chemical identifiers, and deposited to the open MolSSI QCArchive database for future use. This work is part of the Open Force Field Initiative, a collaborative effort to produce open source tools, generate open force fields, and produce open datasets with utility beyond force field parameterization.

Is the Force with us? Automating generalizable torsions

2019 Spring National Meeting

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