论文标题
从头算在BA-BI液体中具有强烈有序趋势的助理的分子动力学探索
An ab initio molecular dynamics exploration of associates in Ba-Bi liquid with strong ordering trends
论文作者
论文摘要
虚拟的同伴被广泛用于描述和模拟具有强大顺序趋势的液相。但是，在大多数情况下，对假定同伴的证据很少。在目前的工作中，采用了一项从头算分子动力学（AIMD）研究来研究BA-BI液体的特征，在现有的热力学建模中已经假定了同伴。发现在BA丰富的熔体中，双原子几乎完全被BA原子包围。双重以双重配位多面体与AIMD模拟期间其他多面体的BA5BI3和BA4BI3的结晶结构密切相关。另外，这些以BA丰富的双重融化为中心的多面体通过顶点，边缘，面部和/或双吡咯共享形成中等范围（MRO）。在BI丰富的熔体中，以BA为中心的多面体也形成了MRO，但它们在结构和成分上既有寿命较短。 AIMD研究的这些发现提供了证据表明，有强烈的订购BA4BI3合伙人和BA-BI液体中有弱有序的BABI3助理。液体中混合的预测焓与文献中的calphad建模的结果非常吻合。
Fictive associates are widely used to describe and model liquid phases with strong ordering trends. However, little evidence is known about the assumed associates in most cases. In the present work, an ab initio molecular dynamics (AIMD) study is employed to investigate the characters of the Ba-Bi liquid, in which associates have been assumed in existing thermodynamic modeling. It is found that in the Ba rich melt, the Bi atoms are almost completely surrounded by Ba atoms. The Bi-centered coordination polyhedrons are strongly associated to crystalline structures of Ba5Bi3 and Ba4Bi3 with a longer lifetime than other polyhedrons during the AIMD simulations. In addition, these Bi-centered polyhedrons in Ba rich melt connect with each other through vertex, edge, face, and/or bipyramid sharing to form medium range orders (MRO). In the Bi rich melt, the Ba-centered polyhedrons also form MROs, but they are both structurally and compositionally diverse with a shorter lifetime. These findings from AIMD study provide evidences that there exist a strongly ordering Ba4Bi3 associate and a weakly ordering BaBi3 associate in the Ba-Bi liquid. The predicted enthalpy of mixing in the liquid agrees well with the results by the CALPHAD modeling in the literature.
