Improved Ab Initio Molecular Dynamics by Minimal Biasing with Experimental Data

TL;DR

This paper introduces a maximum-entropy method to incorporate experimental data into ab initio molecular dynamics, significantly improving the accuracy of water simulations and providing insights into density functional theory inaccuracies.

Contribution

The authors develop a minimal biasing approach using maximum-entropy principles to enhance AIMD accuracy with limited experimental data.

Findings

Improved simulation accuracy for water properties.

Enhanced modeling of excess protons in water.

Gained insights into density functional theory limitations.

Abstract

Accounting for electrons and nuclei simultaneously is a powerful capability of ab initio molecular dynamics (AIMD). However, AIMD is often unable to accurately reproduce properties of systems such as water due to inaccuracies in the underlying electronic density functionals. This shortcoming is often addressed by added empirical corrections and/or increasing the simulation temperature. We present here a maximum-entropy approach to directly incorporate limited experimental data via a minimal bias. Biased AIMD simulations of water and an excess proton in water are shown to give significantly improved properties both for observables which were biased to match experimental data and for unbiased observables. This approach also yields new physical insight into inaccuracies in the underlying density functional theory as utilized in the unbiased AIMD.