Local structures of MD-modeled vitreous silica and sodium silicate glasses

First-Principles Investigation of Low EnergyE′Center Precursors in Amorphous Silica

“…Each sample, stoichiometric and oxygen-deficient, was then slowly annealed from 4000K to 300K under isobaric conditions at a rate of 1.67 K/ps. This rate is slower than those used in previous studies [13,14], and results in well-annealed a-SiO 2 structures with a lower incidence of unphysical network artifacts. All samples were treated as neutral, with no net charge.…”

“…Three-and five-fold Si have been reported in previous simulations [13,17]-fast cooling rates in MD simulation tend to artificially trap large numbers of these defects-however, their formation energy has not been reported. Their appearance as isolated defect pairs in our simulations with slower cooling rates and low formation energies indicate that III-Si and V-Si are likely a native defects in a-SiO 2 .…”

Nuclear Energy Advanced Modeling and Simulation (NEAMS) Waste Integrated Performance and Safety Codes (IPSC) : FY10 development and integration.

“…Numerous classical MD simulation studies have been performed to model glass structures and to examine the diffusion of ions in glass with time (Cabaret et al 2001;Cormack et al 2002;Du and Cormack 2004;Ganster et al 2007;Pedone et al 2006;Tilocca et al 2006;2007;Yuan and Cormack 2001). Some of these studies combine calculations with structure analyses.…”

Radiation-Induced Topological Disorder in Irradiated Network Structures

“…All four initial configurations were scaled to the same density of 2200 kg/m 3 within a box size of 2.83 nm on a side. The two-body van Beest-Kramer-van Santen (BKS) potential function [90] was used because it appears to be on of the best for silicates [48,91,92]. In order to reduce the negative pressure in vitreous silica, a short-range potential cutoff of 0.55 nm was used, with no noticeable structural change observed.…”

“…Similarly, the successful MD modeling of SiO 2 topological arrangements holds lessons for extension of modeling efforts to more complex silicate structures involving other cations (Na, Ca, Zr) for which satisfactory atomic potentials [47,48] have been developed and also into the elemental silicon network, regarding which there is a current interest in radiation-induced degradation of microelectromechanical (MEMS) devices [49]. The latter effort has been embarked upon with the assistance of Professor Martin Bazant, recently arrived from Harvard, who has recently developed a new coordination-affected potential for Si [50].…”