A series of molecular dynamics (MD) calculations1 has been carried out to visualize the atomic configuration in MgSiO3 melt and glass. The 'computer-generated' configuration seemed to be realistic. At zero pressure the Si-O-Si angle distribution gave a clear peak at ∼145°in agreement with the result of ordinary X-ray study on vitreous SiO2 (ref. 2). Coordination of O around Mg was irregular, because the whole structure is dominated by packing of the rather regular SiO4 tetrahedra which are linked together by sharing O atoms at corners. The 'melt' also showed a partial conversion from a 4- to 6-coordination state on 'compression' within a reasonable density range, accompanied by a steady decrease in the Si-O-Si angles. The MD calculation, which is simply the numerical integration of the classical newtonian equations of motion for many particles in a hypothetical periodic space, has been successfully applied to various molten ionic salt systems1. Following Woodcock et al's3 first application of MD to vitreous SiO2, we decided to extend the MD calculation to systems of geochemical importance and report our results here.
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