Towards a Mechanism Underlying the Stability of the Tetragonal CuO Phase： Comparison with NiO and CoO by Hybrid Density Functional Calculation

By means of hybrid density functional theory, we interpret the stability mechanism of the tetragonal CuO phase, which was synthesized using the pulsed laser deposition. The orbital ordering resulted from the crystal field splitting is found to be favorable for the do electronic configuration of the Cu2＋ ion, yielding two possible metastable tetragonal phases （c/a 〈 1 and c/a 〉 1） of CuO. A detailed comparison is also performed with the ideal rock-salt compounds CoO and NiO.     

化合物生成焓:一百年和密度泛函基量子机制的原子模型新时代

讨论基于量子理论的密度泛涵基的原子模型在计算化合物生成焓方面的成功应用,并用此方法分析和计算了七个Mn基Laves相金属简化合物RMn2(R=Sc,Y,Lu,Ti,Zr,Hf,Nb)的标准热力学生成焓.同时,也简单地述评了传统的实验方法和计算模型的发展历史和现状,指出其主要不足.通过与可靠实验数据的对比,实现这一新方法的可靠性和准确性.     

Ab initio study of dynamical properties of U-Nb alloy melt

The U-Nb alloy, as a kind of nuclear material with good corrosion resistance and mechanical properties, plays an important role in the nuclear industry. However, the experimental measurements and theoretical calculations of many parameters which are essential in describing the dynamical properties of this alloy melt, including density, diffusivity, and viscosity, have not been carried out yet. The lack of data on the dynamical properties of nuclear materials seriously hinders the high-performance nuclear materials from being developed and applied. In this work, the dynamical properties of the U-Nb alloy melt are systematically studied by means of ab initio molecular dynamics simulations and their corresponding mathematical models are established, thereby being able to rapidly calculate the densities, diffusion coefficients, viscosities, and their activation energies in the whole U-Nb liquid region. This work provides a new idea for investigating the dynamical properties of binary alloy melts, thereby promoting the development of melt research.