金属铍热力学性质的理论研究

Theoretical study of thermodynamic properties of metal Be

使用第一性原理方法结合平均场模型研究了压力从0到150GPa、温度从0到1500K,金属铍六角密排结构(hcp)的热力学性质,包括铍的常态性质,等温高压物态方程,以及常压下平衡体积、体弹模量随温度的变化,Hugoniot曲线等.0K物态方程由广义梯度近似下的密度泛函理论计算,粒子热运动的贡献由平均场模型计算.由于铍的Debye温度比较高,计算自由能时考虑了零点振动能修正.计算结果与已有的静力学和冲击波实验数据符合得非常好.

We present first-principles calculations combined with mean-field potential model to study the thermodynamic properties of hexagonal-close-packed （hcp） Be for pressures up to 150 GPa and temperatures up to 1500 K, including the properties of Be under ambient conditions, the isothermal equation of state up to high pressure, the temperature dependence of equilibrium volumes and bulk modulus under ambient pressure, and Hugoniot curve in the P-V plane. The equation of state at zero temperature is computed based on density-functional theory within the generalized-gradient approximation. The vibrational contributions are calculated by the mean-field potential model. Due to high Debye temperature of Be, we consider the zero-point energy correction to the free energy. The calculated properties are in good agreement with available static and shock-wave experimental measurements.