The Bearings from Rare-Earth (RE = La, Lu, Sc, Y) Cations on the Oxygen Environments in Aluminosilicate Glasses: A Study by Solid-State 17O NMR, Molecular Dynamics Simulations, and DFT Calculations

Abstract

Aluminosilicate (AS) glasses incorporating trivalent cations of rare-earth (RE) elements exhibit a significant structural disorder and manifest building blocks incommensurate with conventional glass structure models. We present a comprehensive experimental and computational study of the O speciations in RE2O3–Al2O3–SiO2 glasses with RE = {La3+, Y3+, Lu3+, Sc3+}, where the cations are ordered according to increasing field-strength. The coexisting 17O[p]–Sip–mAlm moieties were quantified by magic-angle-spinning (MAS) 17O nuclear magnetic resonance (NMR) experiments and atomistic molecular dynamics (MD) simulations. Experimental 17O quadrupolar products (CQη) and isotropic chemical shifts (δiso) agreed well with predictions from density functional theory with the projector augmented wave (PAW) and gauge including PAW approaches, respectively. We highlight an observed strong influence of both {δiso, CQη} NMR parameters on the average number of 17O[p]–RE3+ contacts (q) and establish simple correlations betwee...