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

09 September 2020, Version 1
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

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.

Keywords

QM/MM
many-mody models
molecular interactions
hydration
density functional theory
polarization
exchange-repulsion
charge transfer

Supplementary materials

Title
Description
Actions
Title
qm-mbmm si
Description
Actions

Comments

Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.