PNNL

Abstract

The source of the experimentally observed anomalous behavior of the First Sharp Diffraction Peak (FSDP) in lithium silicate glasses, as compared to silica and sodium silicate glasses, was determined using classical molecular dynamics simulations. Partial structure factors and swapping of the scattering length of lithium and sodium ions were used to determine the contributions to the FSDPs. The latter approach clearly establishes that the major difference of the FSDP between lithium and sodium disilicate glasses is due to the negative scattering length of lithium ions. Additionally, it was determined that the unusual intense FSDP in lithium silicate glass has little to do with differences of the medium range structure in these glasses.