Python Group Additivity (pGrAdd) software for estimating species thermochemical properties

Increasingly complex chemistry models require thermochemical data for many species often estimated from costly first-principles DFT computations. We introduce the Python Group Additivity software (pGrAdd) that implements comprehensive group additivity in a simple, modular, lightweight Python package that is extensible and easy to implement. It includes 6 group additivity databases for gas species and Pt(111) adsorbates allowing users to immediately compute thermochemical properties for a wide range of molecules and build new databases.