Theoretical study on crystal morphologies of 1,1-diamino-2,2-dinitroethene in solvents: Modified attachment energy model and occupancy model

Abstract

In this study, the growth morphologies of 1,1-diamino-2,2-dinitroethene (FOX-7) in vacuum and solvent conditions were investigated by molecular dynamics simulation. The modified attachment energy (MAE) model and occupancy model were used separately to predict the crystal morphology by calculating relative growth rate of different crystal faces in H₂O/NMP and DMSO/AC solvent system. The calculated results show that the (0 1 1) face and (1 0 1) face are the most important crystal face in both two solvents towards the MAE model and the occupancy model, respectively. Compared with that from the MAE model, the predicted morphologies from the occupancy model are in better agreement with the experimental results. Radial distribution function (RDF) analyses were employed to demonstrate that the hydrogen bonds and vdW interactions play the dominant role between solvent molecules and FOX-7 surfaces. The above results allow us to understand the role played by solvents and solute molecules on growth morphologies of FOX-7 crystals.