Electronic structure and optical properties of α-RDX crystal under pressure from first-principles calculations

Abstract

ABSTRACTIn this study, we investigate the electronic structure and optical properties of α-RDX crystal under pressure from 0 to 4 GPa using first-principles calculations based on the density functional theory. When pressure increases, the calculations figure out that the band gap linearly decreases, the peaks of the total density of states are lowered, the valence bandwidths broadened and the conduction bandwidths compressed. The results also show that the optical properties including dielectric function, absorption spectrum, refractive index, reflectivity and energy-loss function respond to compression, that is, the intensity of the maximal peak of absorption coefficient increases from 7.07 × 104 to 7.98 × 104 cm−1 with corresponding photon energy from 5.10 to 5.15 eV, the static refractive index increases from 1.23 to 1.30, the intensity of the maximal peak of reflectivity function increases from 0.24 to 0.32 accompanied by its photon energy from 5.74 to 5.97 eV, and the plasma resonance energy and its intensity increases from 5.92 to 6.20 eV and 3.81 to 5.13, respectively.