On fitting a gold embedded atom method potential using the force matching method
On fitting a gold embedded atom method potential using the force matching method
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DOI：
10.1063/1.2124667
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发表时间：
2005-11-22
影响因子：
4.4
通讯作者：
Snook, IK
中科院分区：
文献类型：
--
作者：
Grochola, G;Russo, SP;Snook, IK
我们采用改进的力匹配方法拟合了一个新的金嵌入原子法（EAM）势，其中包括拟合高温固体晶格常数和液体密度。与Foiles、Baskes和Daw（FBD）[Phys. Rev. B 33，7983（1986）]约翰逊[Phys. Rev. B 37，3924（1988）]的先前势相比，新势显示出与实验晶格常数、弹性常数、堆垛层错能、径向分布函数和fcc/hcp/bcc晶格能差一致的良好的总体改进，Ercolessi [Philos.Mag.A50，213（1988）]的胶模型势。与FBD和约翰逊的电势相比，表面能略有提高，但结果，与相同的电势相比，空位形成能略差。这里获得的结果表明，对于其他金属物种，在EAM框架内，通过改进的拟合方法，仍然可以进一步全面改善电位。另一方面，我们也探讨了EAM框架的局限性，试图蛮力适合所有的属性，这是不成功的。这种蛮力拟合的主要冲突是表面能和液体晶格常数之间的矛盾，两者不能完全相同地拟合。通过有意地使用大量的样条部分的对势，电子密度函数，和嵌入能量函数，我们消除了缺乏功能的自由作为这种冲突的一个可能原因，因此可以得出结论，它必须从EAM框架中的基本限制。
We fit a new gold embedded atom method (EAM) potential using an improved force matching methodology which included fitting to high-temperature solid lattice constants and liquid densities. The new potential shows a good overall improvement in agreement to the experimental lattice constants, elastic constants, stacking fault energy, radial distribution function, and fcc/hcp/bcc lattice energy differences over previous potentials by Foiles, Baskes, and Daw (FBD) [Phys. Rev. B 33, 7983 (1986)] Johnson [Phys. Rev. B 37, 3924 (1988)], and the glue model potential by Ercolessi [Philos. Mag. A 50, 213 (1988)]. Surface energy was improved slightly as compared to potentials by FBD and Johnson but as a result vacancy formation energy is slightly inferior as compared to the same potentials. The results obtained here for gold suggest for other metal species that further overall improvements in potentials may still be possible within the EAM framework with an improved fitting methodology. On the other hand, we also explore the limitations of the EAM framework by attempting a brute force fit to all properties exactly which was found to be unsuccessful. The main conflict in such a brute force fit was between the surface energy and the liquid lattice constant where both could not be fitted identically. By intentionally using a very large number of spline sections for the pair potential, electron-density function, and embedding energy function, we eliminated a lack of functional freedom as a possible cause of this conflict and hence can conclude that it must result from a fundamental limitation in the EAM framework.