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首页> 外文期刊>Journal of Non-Crystalline Solids: A Journal Devoted to Oxide, Halide, Chalcogenide and Metallic Glasses, Amorphous Semiconductors, Non-Crystalline Films, Glass-Ceramics and Glassy Composites >Molecular dynamic simulation on the structure of sodium germanate glasses
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Molecular dynamic simulation on the structure of sodium germanate glasses

机译：锗酸钠玻璃结构的分子动力学模拟

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The structure of Na2O-GeO2 glasses has been investigated, using molecular dynamics (MD) simulations based on an empirical three-body interaction model. A multi-body potential function with two energy minima in the angular term for a given three-atom unit was introduced to permit a transformation between different coordination states, such as 4-and 6-fold coordinated Ce sites. Parameters in the potential function were optimized with a non-linear least-squares (NLS) method. The optimal parameter set obtained with a Na4Ge9O20 crystal was employed for the structural models of pure GeO2 and 2Na(2)O . 9GeO(2) glasses. In the model for the binary glass, however, a number of 5-fold coordinated Ge, non-bridging O and 3-fold coordinated O formed. Another binary model free from 5-fold Ge was prepared using a simple scheme in which no three-body interaction was applied to the structural units containing 5-fold coordinated Ge. All the structural models produced showed good agreement with the experiments, including vibrational spectra and radial distribution functions (RDFs). No significant difference between the experimental observables of the two binary glass models was revealed, except for the coordination environment of Ge. This is because 5- and B-fold Ge do not occur in a discrete arrangement through a corner-sharing of GeO4, e.g. GeO5.6-GeO4-GeO5.6, but in a dense configuration, e.g. as edge-sharing GeO5.6-GeO5.6, forming smaller rings than those in pure GeO2 glass. (C) 2000 Elsevier Science B.V. All rights reserved. [References: 45]
机译：已使用基于经验三体相互作用模型的分子动力学（MD）模拟研究了Na2O-GeO2玻璃的结构。引入了在给定的三个原子单元的角度项中具有两个能量最小值的多体势函数，以允许在不同配位态（例如4和6倍配位Ce位置）之间进行转换。使用非线性最小二乘（NLS）方法优化了势函数中的参数。用Na4Ge9O20晶体获得的最佳参数集用于纯GeO2和2Na（2）O的结构模型。 9GeO（2）眼镜。然而，在用于二元玻璃的模型中，形成了许多5倍配位Ge，无桥O和3倍配位O。使用简单的方案制备了另一种不含5倍Ge的二元模型，其中没有三体相互作用应用于包含5倍配位Ge的结构单元。所产生的所有结构模型都与实验吻合良好，包括振动光谱和径向分布函数（RDF）。除了Ge的配位环境外，两个二元玻璃模型的实验观察值之间没有显着差异。这是因为通过GeO 4的拐角共享，例如在5和2倍的Ge中不会通过GeO 4的拐角共享而离散地发生。 GeO5.6-GeO4-GeO5.6，但处于密集配置，例如作为边缘共享的GeO5.6-GeO5.6，形成的环比纯GeO2玻璃中的环小。 （C）2000 Elsevier Science B.V.保留所有权利。 [参考：45]

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