A coarse-grain force field for RDX: Density dependent and energy conserving

JD Moore and BC Barnes and S Izvekov and M Lisal and MS Sellers and DE Taylor and JK Brennan, JOURNAL OF CHEMICAL PHYSICS, 144, 104501 (2016).

DOI: 10.1063/1.4942520

We describe the development of a density-dependent transferable coarse- grain model of crystalline hexahydro-1,3,5-trinitro-s-triazine (RDX) that can be used with the energy conserving dissipative particle dynamics method. The model is an extension of a recently reported one- site model of RDX that was developed by using a force-matching method. The density-dependent forces in that original model are provided through an interpolation scheme that poorly conserves energy. The development of the new model presented in this work first involved a multi-objective procedure to improve the structural and thermodynamic properties of the previous model, followed by the inclusion of the density dependency via a conservative form of the force field that conserves energy. The new model accurately predicts the density, structure, pressure-volume isotherm, bulk modulus, and elastic constants of the RDX crystal at ambient pressure and exhibits transferability to a liquid phase at melt conditions. (C) 2016 AIP Publishing LLC.

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