Figure1

Figure 1. Lattice energy as a function of density of (A) $$ \beta $$-HMX, (B) $$ \varepsilon $$-CL-20, and (C) 1:1 HMX: CL-20 cocrystal; Energy of molecular (D) HMX and (E) CL-20 as a function of N–NO₂ bond distance; (F) Comparison of DFT- and ReaxFF-nn-calculated lattice energies of 1:1 cocrystal structures randomly generated by USPEX. HMX: 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane; CL-20: 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane; DFT: density functional theory; ReaxFF-nn: reactive force field with neural networks; USPEX: Universal Structure Predictor: Evolutionary Xtallography.