Molecular dynamics simulation of uniaxial and adiabatic compression of β-HMX crystal

The uniaxial compression of β-HMX crystals in three orientations of (100), (010) and (001) were calculated through molecular simulations using COMPASS (Condensed-Phase Optimized Molecular Potential for Atomistic Simulation Studies) force field. The isotherms of the three orientations are different, which indicates that the β-HMX has anisotropic compression property. The adiabatic hydrostatic compressions of β-HMX were also simulated in NpH ensemble. The adiabatic is above the isotherms and in better agreement with the shock experiments. The temperatures of β-HMX were simulated by molecular dynamics and compared with the shock temperatures of β-HMX calculated with approximation theoretical method. Although there were some small deviations between the simulated and the calculated shock temperatures, the simulation of compression of β-HMX crystals in NpH ensemble is suitable for predicting the shock temperature of β-HMX explosive. COMPASS force field is applicable to describe the adiabatic compression of β-HMX. The simulation of adiabatic compression of explosive using molecular dynamics can predict the shock temperature of explosive.