OPLS5: Addition of Polarizability and Improved Treatment of Metals

We report on the development and validation of the OPLS5 force field. OPLS5 further extends the accuracy of our previous model (OPLS4) with the addition of explicit polarization to improve model accuracy for molecular ions and cation-pi interactions. OPLS5 also includes advances to the functional form for metals achieving significant improvements across benchmarks assessing the structure and energetics of metal-organic complexes. Together these advances lead to improved accuracy on our protein-ligand binding benchmarks.