Ab initio molecular dynamics study of 45S5 bioactive silicate glass.
Ab initio molecular dynamics study of 45S5 bioactive silicate glass.
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DOI：
10.1021/jp065146k
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发表时间：
2006-12
期刊：
影响因子：
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通讯作者：
A. Tilocca;N. D. de Leeuw
中科院分区：
文献类型：
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作者：
A. Tilocca;N. D. de Leeuw
采用Car-Parrinello分子动力学（CPMD）模拟方法对生物活性熔融淬火硅酸盐玻璃原型——生物玻璃45S5进行了建模。虽然远程结构特性不能通过使用这种从头算方法来建模，但CPMD模拟的准确性在这里被利用来提供对短程结构的洞察，并分析这种生物材料的振动和电子特性。在短期尺度上的详细结构分析提供了对改性剂Na和Ca离子的局部环境的洞察：这些阳离子通过将不同的链和碎片连接成特定的、相当灵活的几何形状，在组织玻璃网络中可能发挥关键作用。我们分离并讨论了不同物质对振动态密度的贡献，从而确定了振动谱中的特定特征，例如与磷酸基团相关的特征。我们还分析了电子态密度的组成，使我们能够确定电子结构与结构性质之间的相关性，例如涉及桥接氧原子或非桥接氧原子的Si-O键的不同成键特性。
Bioglass 45S5, the prototype of bioactive melt-quenched silicate glasses, was modeled by means of Car-Parrinello molecular dynamics (CPMD) simulations. Although long-range structural properties cannot be modeled by using this ab initio approach, the accuracy of CPMD simulations is exploited here to provide insight into the short-range structure and to analyze vibrational and electronic properties of this biomaterial. Detailed structural analysis in the short-range scale provided insight into the local environment of modifier Na and Ca ions: a possible key role of these cations in organizing the glass network by connecting different chains and fragments into specific, rather flexible geometries was proposed. The individual contributions of different species to the vibrational density of states were separated and discussed, allowing the identification of specific features in the vibrational spectrum, such as those related to phosphate groups. The components of the electronic density of states were also analyzed, enabling us to identify correlations between the electronic structure and the structural properties, such as the different bonding character of Si-O bonds involving bridging or nonbridging oxygen atoms.