Impact sensitivity and moisture adsorption on the surface of CL-20/TNT cocrystal by molecular dynamics simulation

Water molecules in the air can be absorbed on the surface of the explosives in storage and transport process, which may lead to the transformation of sensitivity and storage safety. The interactions between cocrystal and water molecules are identified as a process of physical adsorption. To explore the effects of moisture sorption on the storage safety, this paper took the cocrystal composed of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and 2,4,6-trinitrotoluene (TNT) in a 1:1 M ratio as the research object, and molecular dynamics simulation was conducted on the cocrystal for (0 0 1), (0 1 0), (1 0 0) crystal plane in COMPASS (condensed-phase optimized molecular potentials for atomistic simulation studies) force field. It turns out that there are hydrogen bonding interactions between the water molecules and the molecules in the cocrystal by analyzing the Radial distribution function diagrams. The length of trigger bond and the cohesive energy density of the cocrystal are adopted as theoretical criterion of sensitivity. The results indicate that it takes less energy for the NN bonds to rupture and the explosives would have higher sensitivity when water molecules are absorbed on the surface.