An alternative use of Kieffer’s lattice dynamics model using vibrational density of states for constructing thermodynamic databases
An alternative use of Kieffer’s lattice dynamics model using vibrational density of states for constructing thermodynamic databases
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DOI：
10.1007/s00269-012-0562-4
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发表时间：
2013-01
影响因子：
1.4
通讯作者：
M. Jacobs;R. Schmid-Fetzer;A. P. Berg
中科院分区：
文献类型：
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作者：
M. Jacobs;R. Schmid-Fetzer;A. P. Berg
我们使用Kieffer模型来表示纯物质在压力-温度空间中的振动态密度（VDoS）和热力学性质。我们表明，该模型可以简化为振动模型，其中vdo由多个爱因斯坦频率表示，而热力学性质相对于实验数据的准确性没有显着损失。所得到的热力学性质的解析表达式，包括吉布斯能量，在数学上是简单的，很容易适应于现有的计算软件，以建立热力学数据库。我们表明，对于铝、铂、正长辉石和长辉石，热力学性质可以用与mie - gren - neisen - debye模型具有相同数量拟合参数的Kieffer模型以相当的精度表示。我们证明，相对于mie - gren - neisen - debye方法，该方法能够以更高的精度获得热力学性质。这种方法是通用的，因为它允许合并粗<s:1>尼森参数的色散。可以扩展形式主义，使其包括其他物理效应，如基于基弗形式主义的振动模型中的固有非调和性。
We use Kieffer’s model to represent the vibrational density of states (VDoS) and thermodynamic properties of pure substances in pressure–temperature space. We show that this model can be simplified to a vibrational model in which the VDoS is represented by multiple Einstein frequencies without significant loss of accuracy in thermodynamic properties relative to experimental data. The resulting analytical expressions for thermodynamic properties, including the Gibbs energy, are mathematically simple and easily accommodated in existing computational software for making thermodynamic databases. We show for aluminium, platinum, orthoenstatite and forsterite that thermodynamic properties can be represented with comparable accuracy as with Kieffer’s model with the same number of fitting parameters as in the Mie–Grüneisen–Debye model. We demonstrate that the method enables to achieve thermodynamic properties with superior accuracy relative to the Mie–Grüneisen–Debye method. The method is versatile in the sense that it allows incorporating dispersion of Grüneisen parameters. It is possible to extend the formalism to include other physical effects, such as intrinsic anharmonicity in the same way as in vibrational models based on Kieffer’s formalism.