Molecular Solid EOS based on Quasi-Harmonic Oscillator approximation for phonons

Menikoff, Ralph¹ 

[1] Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

关键词: EOS;    MOLECULAR SOLID;    PHONON SPECTRUM;   

DOI  :  10.2172/1159050
RP-ID  :  LA-UR--14-26858
PID  :  OSTI ID: 1159050

学科分类：数学（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

A complete equation of state (EOS) for a molecular solid is derived utilizing a Helmholtz free energy. Assuming that the solid is nonconducting, phonon excitations dominate the specific heat. Phonons are approximated as independent quasi-harmonic oscillators with vibrational frequencies depending on the specific volume. The model is suitable for calibrating an EOS based on isothermal compression data and infrared/Raman spectroscopy data from high pressure measurements utilizing a diamond anvil cell. In contrast to a Mie-Gruneisen EOS developed for an atomic solid, the specific heat and Gruneisen coefficient depend on both density and temperature.