A simple energy-scaling scheme for fine-tuning empirical potentials for coupled quantum mechanical/molecular mechanical studies

Empirical potentials that are commonly used in molecular mechanical (MM) calculations often exhibit marked differences from quantum mechanical (QM) calculations. These differences can lead to mismatches in the mechanical properties of different subdomains in coupled QM/MM calculations that can result in artifactual behavior or low accuracy. We present a simple strain-dependent energy-scaling approach that can adjust the mechanical properties of the MM potential to better match those of the QM potential. Multiscale fracture studies of defective graphene sheets are performed and benchmarked against strictly QM calculations to illustrate the effectiveness of this method.