Solvation Free Energies in Subsystem Density Functional Theory

TL;DR

This paper introduces a hybrid subsystem density functional theory approach combined with continuum models to accurately and efficiently compute solvation free energies, maintaining transferability and scalability across various solvents and solutes.

Contribution

It presents a novel hybrid model that combines subsystem DFT with continuum solvation schemes, enhancing transferability and scalability in solvation energy calculations.

Findings

Accurately reproduces reaction barriers and energies compared to experiments.

Demonstrates transferability across different solvents and solutes.

Shows scalability with increasing numbers of subsystems.

Abstract

For many chemical processes the accurate description of solvent effects are vitally important. Here, we describe a hybrid ansatz for the explicit quantum mechanical description of solute-solvent and solvent-solvent interactions based on subsystem density functional theory and continuum solvation schemes. Since explicit solvent molecules may compromise scalability of the model and transferability of the predicted solvent effect, we aim to retain both, for different solutes as well as for different solvents. The key for the transferability is the consistent subsystem decomposition of solute and solvent. The key for the scalability is the performance of subsystem DFT for increasing numbers of subsystems. We investigate molecular dynamics and stationary point sampling of solvent configurations and compare the resulting (Gibbs) free energies to experiment and theoretical methods. We can show that with our hybrid model reaction barriers and reaction energies are accurately reproduced compared to experimental data.