Structural properties of a calcium aluminosilicate glass from molecular-dynamics simulations: A finite size effects study

TL;DR

This study uses molecular-dynamics simulations to investigate how finite size effects influence the structural properties of a calcium aluminosilicate glass, highlighting the impact of three-body interactions on simulation accuracy.

Contribution

It provides a detailed analysis of finite size effects in MD simulations of calcium aluminosilicate glass, emphasizing the role of three-body interactions in structural deviations.

Findings

Finite size effects alter angular distributions and pair correlation peaks.

Small systems show different Ca coordination and oxygen environments.

Three-body interactions are responsible for observed finite size effects.

Abstract

We study a calcium aluminosilicate glass of composition (SiO$_2$)$_{0.67}$-(Al$_2$O$_3$)$_{0.12}$-(CaO)$_{0.21}$ by means of molecular-dynamics (MD) simulations, using a potential made of two-body and three-body interactions. In order to prepare small samples that can subsequently be studied by first-principles, the finite size effects on the liquid dynamics and on the glass structural properties are investigated. We find that finite size effects affect the Si-O-Si and Si-O-Al angular distributions, the first peaks of the Si-O, Al-O and Ca-O pair correlation functions, the Ca coordination and the oxygen atoms environment in the smallest system (100 atoms). We give evidence that these finite size effects can be directly attributed to the use of three-body interactions.