A study of the solvent effect on the crystal morphology of hexogen by means of molecular dynamics simulations

Abstract

In this work, molecular dynamics simulations have been performed to study the solvent effect on the crystal morphology of hexogen. The hexogen growth habits in a vacuum predicted by the AE model are dominated by the (111), (020), (200), (002), and (210) faces. Hexogen surfaces–acetone solvent micro interface models are constructed to study the adsorption behavior of acetone on these habit planes. The modified attachment energy model considering both the solvent–surface adsorption interactions and surface structures is proposed to predict the crystal morphology of hexogen in the acetone solvent. The calculations of the modified attachment energies suggest that via the effect of acetone solvent, the (210) face has the largest morphology importance and the morphological importance of the (111), (002) and (200) faces reduces, whereas the (020) face disappears. The predicted result is in reasonable agreement with the observed experiment shape. Furthermore, the diffusion coefficients of acetone solvent toward the different RDX surfaces suggests that the (210) and (111) faces are the dominate growth faces on the final RDX crystal habits, whereas the (020) face probably disappears, which validates the reliability of the modified attachment energy model.