Parametrization of the Fe-Owater cross-interaction for a more accurate Fe3O4/water interface model and its application to a spherical Fe3O4 nanoparticle of realistic size

TL;DR

This paper develops and validates new force field parameters for accurately modeling Fe3O4/water interfaces, improving the simulation of water interactions with magnetite surfaces and nanoparticles.

Contribution

It introduces optimized Fe-Owater cross interaction parameters based on quantum calculations, enhancing the realism of Fe3O4/water interface models.

Findings

New parameters accurately reproduce water adsorption energies.

Validated transferability on spherical Fe3O4 nanoparticles.

Improved modeling of water density profiles near magnetite surfaces.

Abstract

The accurate description of iron oxides/water interfaces requires reliable force field parameters that can be developed through the comparison with sophisticated quantum mechanical calculations. Here a set of CLASS2 force field parameters is optimized to describe the Fe-Owater cross interaction through comparison with hybrid density functional theory (HSE06) calculations of the potential energy function for a single water molecule adsorbed on the Fe3O4 (001) surface and with density functional tight binding (DFTB+U) molecular dynamics simulations for a water tri-layer on the same surface. The performance of the new parameters is assessed through the analysis of the number density profile of a water bulk (12 nm) sandwiched between two magnetite slabs of large surface area. Their transferability is tested for the water adsorption on the curved surface of a spherical Fe3O4 nanoparticle of realistic size (2.5 nm).