Free energy calculations of a proton transfer reaction by simulated tempering umbrella sampling first principles molecular dynamics simulations

TL;DR

This paper introduces a novel simulated tempering umbrella sampling method for first principles molecular dynamics, enabling efficient and accurate free energy calculations of proton transfer reactions in aqueous solutions.

Contribution

The paper presents a new simulated tempering umbrella sampling technique that improves conformational sampling and free energy calculation efficiency in molecular dynamics simulations.

Findings

Enhanced conformational sampling in reaction coordinate space.

Accurate free energy calculations of proton transfer.

More efficient trajectory data collection than conventional methods.

Abstract

A new simulated tempering method, which is referred to as simulated tempering umbrella sampling, for calculating the free energy of chemical reactions is proposed. First principles molecular dynamics simulations with this simulated tempering were performed in order to study the intramolecular proton transfer reaction of malonaldehyde in aqueous solution. Conformational sampling in reaction coordinate space can be easily enhanced with this method, and the free energy along a reaction coordinate can be calculated accurately. Moreover, the simulated tempering umbrella sampling provides trajectory data more efficiently than the conventional umbrella sampling method.