中文摘要：

基于密度泛函理论，采用投影缀加波方法对不同压力条件下β相奥克托金（β-HMX）的弹性常数进行了计算．计算得到零压条件下β-HMX的体弹性模量为12．7GPa，剪变模量为4．4GPa，与实验测量结果接近．对β-HMX弹性常数压力响应的分析表明，随着外部压力增加，晶体的体弹性模量和剪变模量逐渐增加．当外部压力达到7GPa时晶格开始沿剪应变方向出现不稳定性，与拉曼散射实验结果相符．

英文摘要：

The elastic properties of the β-HMX under an extra pressure are studied from density functional theory calculations using the projector augmented wave method. The calculated bulk modulus and shear modulus under zero pressure are 12.7 GPa and 4.4 GPa which are in good agreement with the available experimental results. A detailed analysis of the pressure-dependent stiffness tensor shows that the bulk modulus and shear modulus both increase as the pressure increases. As the pressure goes up to 7 GPa, the lattice is unstable along the direction of the shear strain. This result agrees well with the results of Raman scattering experiment.