Abstract
A wave-function–based intermolecular potential of the β phase 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane (HMX) molecule has been constructed from first principles using the Williams-Stone-Misquitta method and the symmetry-adapted perturbation theory. Using the potential and its derivatives, we have accurately predicted not only the structure and lattice energy of the crystalline β-HMX at 0 K, but also its densities at temperatures of 0–403 K within an accuracy of 1% of density. The calculated densities at pressures within 0–6 GPa excellently agree with the results from the experiments on hydrostatic compression.