以氧化镁为例研究高温高压下的等温态方程与等温体积弹性模量

从晶格势理论出发,考虑到原子间距对短程力常数的平方效应,得到了固体的等温态方程、体积弹性模量以及体积弹性模量对压强的一阶导数随体积变化而变化的关系式.以氧化镁为例进行了数据处理与分析讨论,结果发现本文在高温(2000K)高压(260GPa)下所得到的理论预测值与普适态方程理论值及PIB模型值十分吻合.

Isothermal Equaiton of State and Isothermal Bulk Modulus at High Temperatures and Pressures:MgO as an Example

Considering the square effect of interatomic separation to the lattice short-range force constant,we obtained a new isothermal equation of state for solids,starting from the theory of lattice potential and using analytical function for the volume dependence of the short-range force constant.Further,the expressions are obtained for isothermal bulk modulus and its pressure derviative.Numerical analysis is presented for MgO at high pressures(up to 260 GPa)and high temperatures(up to 2000 K).The results are discussed and compared with the theory values for MgO by using the potential induced breathing(PIB) electron-gas model based on first principle approach.It is found that the isothermal equation of state obtained in this paper is very applicable even at high temperatures if the experiemental data of input parameters(B0,B'0)corresponding to that temperature are used.