The zero-point vibration contributions to energy and compressibility of light rare-gas solids

Abstract

The zero-point vibration energy, Gruneisen coefficient, and zero-point vibration pressure of light rare-gas solids (LRGS)(He, Ne, Ar) are calculated within a certain range of atomic spacing using many-body expansion and ab initio calculation methods based on quantum and atomic cluster theories. The results are then compared with the previous theoretical calculations and experimental data. It is concluded that the smaller the molar volume of LRGS, the greater the crystal's zero-point vibration energy and vibration frequency. The zero-point vibration energy of LRGSis only 6% of the total many-body interaction energy but should not be neglected. The Grüneisen coefficient of LRGS increases as the molar volume increases. The zero-point vibration pressure is smaller, which is about 3% of the total pressure. The error caused by the pressure calculation is not significant, but when the molar volume is reduced to a fixed value, the zero-point vibration pressure must be considered and cannot be ignored. In addition, the calculation results of zero-point vibration pressure are compared to the previous theoretical calculations and experimental results.