Large Scale Computer Simulation of Glasses. Priya Vashishta¹, Rajiv K. Kalia¹, José Pedro Rino², Gonzalo Gutierrez³ Ingvar Ebbsjö⁴, ¹Concurrent Computing Laboratory for Materials Simulations, Department of Physics and Department of Computer Science, Louisiana State University, Baton Rouge 70803-4001, ²Universidade Federal de São Carlos, Via Washington Luiz Km 235, 13565-905 São Carlos, S.P., Brazil, ³Pont. Univercidad Catolica de Chile, Faculdad de Fisica, Casilla 306 - Santiago 22, Chile, ⁴The Studsvik Neutron Research Laboratory, S-611 82 Nyköping, Sweden

Using the molecular dynamics (MD) method, we have studied the effect of pressure on the distribution of rings and their relationship to intermediate range order manifested as the first sharp diffraction peak (FSDP) for SiO₂ glass. A systematic analysis of the modifications observed in the FSDP for densities ranging from 2.0 to 3.2 g/cm³ and temperatures from 0 to 1500 K is reported. The decrease in the height of the FSDP with increasing density is found to be proportional to the decrease in the number of 6-fold rings. For the density and temperature ranges studied in SiO₂ glass, the full width at half maximum (FWHM) of the FSDP remains unchanged.

This research was supported by the Louisiana LEQSF, DOE, NSF, ARO, AFOSR and DARPA-MURI.