Figure3

Figure 3. (A) Enthalpy and (B) density vs. crystal index from USPEX of 1:2 HMX: CL-20 optimized by DFT (SIESTA) and MLP (ReaxFF-nn). USPEX: Universal Structure Predictor: Evolutionary Xtallography; 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; SIESTA: Spanish Initiative for Electronic Simulations with Thousands of Atoms; MLP: machine learning potential; ReaxFF-nn: reactive force field with neural networks.