LiH的热力学性质及分子内部运动对体系热力学性质的影响

利用基于密度泛函理论的第一性原理平面波超软赝势方法,计算了LiH在零温零压下的晶格常数、体弹模量,计算结果与实验值和其他理论计算值符合得较好.通过准谐德拜模型计算了LiH在压强为0-80GPa、温度为0-2000K范围内,体积膨胀率、热涨系数、德拜温度及定容热容随压强和温度的变化关系.最后,以代数方法（AM）和势能变分法(PVM)为基础,运用统计热力学理论计算了LiH分子内部运动对体系热力学性质的影响.

Thermodynamic properties of LiH and the effect of internal motion of LiH molecules on the thermodynamic properties of system

The lattice constant and bulk modulus of LiH at zero temperature(T=0K) and zero pressure(P=0GPa) was calculated by the first-principle plane-wave density function theory pseudopotential method. The calculated results are in good agreement with experiments and with the other theoretical ca- lculations. Through the quasi-Debye model,We successfully obtained the th- ermodynamic properties of LiH such as volume expansion ratio,thermal exp- ansion coefficient,Debye temperature and the specific heat capacity in the whole temperature range from 0 to 2000K and pressure range from 0 to 80GPa. Finally,based on the algebraic method(AM) and potential energy variational method(PVM),the effect of internal motion of LiH molecules on the thermod- thermodynamic properties of system were calculated by the statistical the- rmodynamic theory.