Structural transformation and absorption properties of 2,4,6-Trinitro-2,4,6-triazacyclohexanone under high pressures

The structural, electronic and absorption properties of 2,4,6-Trinitro-2,4,6-triazacyclohexanone (K-RDX) under hydrostatic compression of 0-100 GPa have been studied by using density functional theory (DFT) calculations. The results show that the variation tendency of lattice constants (a, b, and c) is anisotropic, and b is much stiffer than a and c in the same pressures. The structure transformation occurs at the pressure of 70 GPa leading to two new covalent bonds C2-N5 and O4-N6. The analysis of band gap and density of states (DOS) of K-RDX indicate that it becomes more sensitivity under compression. The absorption spectra show that K-RDX have relatively high optical activity with the increasing pressures and the structure transformation is also observed at 70 GPa. (C) 2019 Elsevier B.V. All rights reserved.