Intermolecular interactions,vibrational spectra,and detonation performance of CL-20/TNT cocrystal

We report the structural properties, intermolecular interactions (Hirshfeld surface analysis and reduced density gradient [RDG] analysis), radial distribution function analysis, vibrational frequencies, and detonation performance for the pure ε-CL-20, TNT, and ε-CL-20/TNT cocrystal to understand how noncovalent interactions affect the impact sensitivity of the cocrystals. The results indicate that the simulated lattice parameters and densities of all the three crystals were consistent with the experiments. Major driving forces for the formation of the ε-CL-20/TNT cocrystal are O H and N O interactions, but the O O interactions may serve as a crucial stabilizing force. The calculated Raman spectra of the CL-20/TNT cocrystal and the experimental result have the same trend. The Roman peaks of the cocrystal in the range 1,200–1,750 cm⁻¹ may result from the coupling of the ε-CL-20 and TNT molecules. Similar crystal packing for TNT and CL-20 leads to the high density for the cocrystal. The cocrystal displays low impact sensitivity because of the p–π interactions. Our work may offer useful information for cocrystallization technology and its practical applications in the field of energetic materials.