Heat-current filtering for Green–Kubo and Helfand-moment molecular dynamics predictions of thermal conductivity: Application to the organic crystal β-HMX

On the definition of heat current for periodic systems and its implications for simulations of thermal conductivity in solids

“…Depending on a specific form of P, this condition may or may not be satisfied. It is satisfied for P given by − i ε i r i considered in this work and for some other choices of P discussed in the literature [14,21]. Note, however, that even if D αβ = 0 it represents a skew-symmetric matrix.…”

“…The main numerical disadvantage of the Green-Kubo approach as implemented in molecular dynamics is a slow convergence of the integral in Eq. ( 1) which may require very long simulation times and careful analysis of the correlation function [6,11,13,14].…”

Thermal conductivity tensor of β‐HMX as a function of pressure and temperature from equilibrium molecular dynamics simulations

“…The rNEMD approach has been applied to predict the thermal conductivities of several different energetic materials [4,7,[18][19][20][21][22][23][24]. The G-K approach was used to determine the thermal conductivity of α-RDX [19] and β-HMX [25] at standard ambient conditions. Most MD studies of thermal conductivity of HMX considered either the liquid state [26] or did not specifically include temperature and pressure effects [4,20,25].…”

“…The G-K approach was used to determine the thermal conductivity of α-RDX [19] and β-HMX [25] at standard ambient conditions. Most MD studies of thermal conductivity of HMX considered either the liquid state [26] or did not specifically include temperature and pressure effects [4,20,25]. Recently, Perriot and Cawkwell [18] studied the pressure and temperature dependence of the β-HMX thermal conductivity tensor for 200 K� T �500 K and 0 GPa � P �5 GPa.…”

“…We employed the nonreactive, fully flexible molecular potential-energy surface (force field) for HMX proposed by Smith and Bharadwaj [29] and further developed by Bedrov et al [30] and others [3,31]. This force field is well-validated and has been used in numerous previous studies of HMX [4,18,25,26,30,[32][33][34][35]. We used the version of the force field first described in Ref.…”