Reactive Potentials for Atomistic Simulation of Sodium Aluminophosphate Glasses: Parameterization and Structural Analysis

Composition-dependent aqueous dissolution of phosphate and aluminophosphate glasses is key to applications, ranging from biomedicine, energy storage to nuclear waste management. Atomistic simulations such as molecular dynamics (MD) are powerful approaches to obtain atomistic level structural information and structure–property relations, as well as gaining insights into the glass–water reaction mechanisms of these glass materials. This requires reactive interatomic potentials that accurately capture the structural features of these glasses and their interactions with water, which are still lacking in the literature. On the basis of our recent development of simple phosphate glasses, we have parameterized the diffuse charge reactive potential (DCRP) for sodium aluminophosphate glasses by fitting both two-body and three-body parameters. Analyses of a series of simulated glasses showed that it was able to reproduce the general structural features of aluminophosphate glasses with a significant amount of higher coordinated aluminum for some compositions, in generally good agreement with experiments. Glass–water reactions related terms were parameterized based on ab initio calculations, and initial testing showed its capability to reproduce surface reactions and formation of P–OH and Al–OH surface groups. The simulated structures with the newly developed potential were validated against the available experimental and simulation data. This paves the way for future simulations of glass–water interactions.