Density functional theory study of high-pressure behavior of crystalline hexanitrostilbene

A detailed study of the structural, electronic, and absorption properties of crystalline hexanitrostilbene (HNS) under hydrostatic pressure of 0-80 GPa was performed with density functional theory. The results show that the structure is much stiffer in the b and c direction than along the a axis, showing that the compressibility of HNS crystal is anisotropic. As the pressure increases, the band gap gradually decreases. An analysis of density of states shows that the electronic delocalization in HNS gradually increases under the influence of pressure. An understanding of the stabilities of HNS under compression based on the electronic structure shows that an applied pressure increases the impact sensitivity of HNS to detonation initiation. As the pressure increases, HNS has relatively high optical activity. The absorption spectra of HNS at high-pressure display a few, strong bands in the fundamental absorption region.