科研之友
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摘要
Disorder in beta-cristobalite is shown to arise from the conformational changes between alpha- and beta-rings (energy barriers of 10-30 meV/SiO2). alpha-rings, remnants from the alpha-beta transformation, constitute alpha-cristobalite. beta-rings are local structures of a new beta%26apos;-cristobalite of symmetry I (4) over bar 2d, confirmed herein by both molecular dynamics simulations and first-principles calculations. The ring conformation in beta-cristobalite features a short correlation time (%26lt; 50 fs) and short correlation length (%26lt; 1 nm), giving the underlying topology framework the ability to support the dynamic disorder.
- 出版日期2012-4-30
