CALCULATION OF RDX MOLECULAR CRYSTAL GEOMETRY AND VIBRATIONAL FREQUENCIES UNDER HYDROSTATIC PRESSURE

First-principles calculations of the effects of hydrostatic pressure on RDX are performed using the all-electron CRYSTAL06 program. The lattice constants and optimized internal coordinates are simultaneously obtained at ambient pressure and hydrostatic pressure up to 2.9 GPa. The vibrational frequencies as a function of pressure are also calculated and compared with experimental results from the literature.