由热学性质获取氩晶体原子间各阶力常数

Calculations of the interatomic force constants of argon crystal from its thermal properties

本文基于晶格动力学和量子力学微扰理论推导了氩晶体的热膨胀系数和比热与原子间相互作用的各阶力常数之间的关系公式,在此基础上根据热膨胀系数和比热的数据计算了氩晶体内的原子间相互作用的各阶力常数,并根据这些力常数绘制了原子间相互作用势能曲线,经比对发现该势能曲线与Morse势能曲线能较好吻合,这表明,本文提出的从热膨胀系数和比热获取各阶力常数的方法是正确的.

The formulas to describe thermal expansion coefficient and heat capacity of argon crystal in terms of interatomic force constants are derived based on the lattice dynamics and perturbation theory of quantum mechanics,and then the interatomic force constants are obtained from thermal expansion coefficients and heat capacities of argon crystal with these formulas. Finally the interatomic potential energy curve is plotted based on these force constants. It is found that this potential energy curve coincides with the Morse potential energy curve well,this means that the method of obtaining the interatomic force constants of argon crystal from thermal properties is correct.