A comparison of ion scattering spectra and molecular dynamics simulations at the surface of silicate glasses

Abstract

Molecular dynamics simulations are correlated with experimental ion scattering spectra to elucidate the surface structure and composition of fused silica and potassium trisilicate glass. The ion scattering spectra and molecular dynamics simulations both show that the oxygen atoms dominate the surface monolayer of fused silica. The ion scattering spectra of fracture surfaces of potassium trisilicate glass show a large potassium signal with little scattering signal from the oxygen or silicon atoms indicating a predominance of potassium in the surface monolayer. This local enrichment of potassium in the surface monolayer is due to their shielding of the charged silicate tetrahedra at the surface. This is also consistent with the simulations.