A Fully Quantum-Mechanical Treatment for Kaolinite

TL;DR

This paper develops neural network potentials for kaolinite based on density functional theory data, compares different functionals, and investigates the impact of nuclear quantum effects on static and dynamic properties.

Contribution

It introduces a fully quantum-mechanical treatment for kaolinite and evaluates the influence of nuclear quantum effects on its properties.

Findings

revPBE + vdW better reproduces static properties

revPBE + D3 better matches experimental IR spectrum

Nuclear quantum effects significantly alter dynamic properties

Abstract

Neural network potentials for kaolinite minerals have been fitted to data extracted from density functional theory calculation that were performed using the revPBE + D3 and revPBE + vdW functionals. These potentials have then been used to calculate static and dynamic properties of the mineral. We show that revPBE + vdW is better at reproducing the static properties. However, revPBE + D3 does a better job of reproducing the experimental IR spectrum. We also consider what happens to these properties when a fully-quantum treatment of the nuclei is employed. We find that nuclear quantum effects (NQEs) do not make a substantial difference to the static properties. However, when NQEs are included the dynamic properties of the material change substantially.