Thermal conductivity tensor of γ and ε-hexanitrohexaazaisowurtzitane as a function of pressure and temperature
Using reverse non-equilibrium molecular dynamics simulations, we have determined the dependences on temperature and pressure of the thermal conductivity tensors for the monoclinic γ and ɛ polymorphs of hexanitrohexaazaisowurtzitane (HNIW or CL20). A recently developed non-reactive force field [X. Bidault and S. Chaudhuri, RSC Adv. 9, 39649–39661 (2019)], designed to study polymorphism and phase transitions in CL20, is employed. The effects of temperature and pressure are investigated between 200 and 500 K and up to 0.5 GPa for γ-CL20 and 2 GPa for ɛ-CL20. In order to obtain the full thermal conductivity tensor, κ ij , for the monoclinic crystals, four distinct heatmore »