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A Many-Body, Fully Polarizable Approach to QM/MM Simulations

preprint
revised on 02.10.2020 and posted on 05.10.2020 by Eleftherios Lambros, Filippo Lipparini, G. Andres Cisneros, Francesco Paesani

We present a new development in quantum mechanics/molecular mechanics (QM/MM) methods by replacing conventional MM models with data-driven many-body (MB) representations rigorously derived from high-level QM calculations. The new QM/MM approach builds on top of mutually polarizable QM/MM schemes developed for polarizable force fields with inducible dipoles and uses permutationally invariant polynomials to effectively account for quantum- mechanical contributions (e.g., exchange-repulsion, and charge transfer and penetration) that are difficult to describe by classical expressions adopted by conventional MM models. Us- ing the many-body MB-pol and MB-DFT potential energy functions for water, which include explicit 2-body and 3-body terms fitted to reproduce the corresponding CCSD(T) and PBE0 2- body and 3-body energies for water, we demonstrate a smooth energetic transition as molecules are transferred between QM and MM regions, without the need of a transition layer. By effectively elevating the accuracy of both the MM region and the QM/MM interface to that of the QM region, the new QM/MB-MM approach achieves an accuracy comparable to that obtained with a fully QM treatment of the entire system.

Funding

U.S. Department of Energy

National Institutes of Health

History

Email Address of Submitting Author

fpaesani@ucsd.edu

Institution

University of California San Diego

Country

United States

ORCID For Submitting Author

0000-0002-4451-1203

Declaration of Conflict of Interest

No conflict of interest

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