DFT study of structural, electronic, and absorption properties of crystalline β-RDX under pressures

Abstract

The structural, electronic, and absorption properties of crystalline hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) under hydrostatic pressure of 0–50 GPa were studied using density functional theory. As the pressure increases, the lattice constants and the unit cell volume decrease gradually. The compressibility of RDX crystal is anisotropic. The different changing trends of bond lengths and bond angles under pressures show that both the ring opening and the N–NO2 cleavage are possible to trigger the RDX decomposition. The interactions between electrons, especially for the valence electrons, are strengthened under the influence of pressure. The absorption spectra of RDX display more and stronger bands in the fundamental absorption region at high pressure.