Property trends in simple metals: An empirical potential approach
Property trends in simple metals: An empirical potential approach
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DOI：
10.1103/physrevb.93.184101
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发表时间：
2016-05-02
影响因子：
3.7
通讯作者：
Ackland, G. J.
中科院分区：
文献类型：
--
作者：
Nichol, A.;Ackland, G. J.
我们证明了碱金属的熔点和其他热力学量可以根据静态结晶性质计算。为此，我们推导出碱金属的解析原子间势，精确地拟合了内聚能和空位能、弹性模量、晶格参数和晶体稳定性。这些电位然后被用来计算熔点，通过模拟固体和液体样品在环境压力下的热接触的平衡。除锂外，与实验值非常吻合。Li和Na中bcc结构在低温下的不稳定性也得到了再现，不同寻常的是，这不是由于软T1N声子模式。拟合中不包括力或有限温度性质，因此这表明简单势具有惊人的高水平的内在可转移性。目前，碱金属的潜力很少，因此，除了展示行为趋势外，我们预计这些潜力将具有广泛的普遍用途。
We demonstrate that the melting points and other thermodynamic quantities of the alkali metals can be calculated based on static crystalline properties. To do this we derive analytic interatomic potentials for the alkali metals fitted precisely to cohesive and vacancy energies, elastic moduli, the lattice parameter, and crystal stability. These potentials are then used to calculate melting points by simulating the equilibration of solid and liquid samples in thermal contact at ambient pressure. With the exception of lithium, remarkably good agreement is found with experimental values. The instability of the bcc structure in Li and Na at low temperatures is also reproduced and, unusually, is not due to a soft T1N phonon mode. No forces or finite-temperature properties are included in the fit, so this demonstrates a surprisingly high level of intrinsic transferability in the simple potentials. Currently, there are few potentials available for the alkali metals, so in addition to demonstrating trends in behavior, we expect that the potentials will be of broad general use.