Theoretical investigations on CL‑20/ANTA cocrystal explosive via molecular dynamics method

Abstract Context In this study, we developed structural models of hexanitrohexaazaisowurtzitane (CL-20)/3-amino-5-nitro-1,2,4-triazole (ANTA) with different molar ratios ranging from 4:1 to 1:4. We employed a combination of density functional theory and molecular dynamics simulations to investigate the surface electrostatic potential, binding energy, initiation bond length, radial distribution function, cohesive energy density, and mechanical properties of CL-20 and ANTA molecules, as well as the aforementioned models. Additionally, we utilized EXPLO-5 software to predict the detonation properties and products of pure CL-20, ANTA, and CL-20/ANTA systems. The results revealed that there was an interaction between CL-20 and ANTA molecules, which had the potential to form a cocrystal. The most likely molar ratio for cocrystal formation was 1:1, and the main driving forces for cocrystal formation were electrostatic force, dispersion force, and van der Waals force. The cocrystal exhibited moderate sensitivity and excellent mechanical properties. Furthermore, the cocrystal detonation performance at a molar ratio of 1:1 was between that of CL-20 and ANTA, representing a new type of insensitive high-energy material. Methods The properties of CL-20/ANTA cocrystal were predicted by molecular dynamics (MD) method under Materials Studio software. For the whole MD simulations, set the temperature at 298 K, and the pressure was 0.0001 GPa. Carried out MD simulation under the NPT ensemble with a total simulation time of 1 ns. The first 0.5 ns was used for thermodynamic equilibrium, and the last 0.5 ns was used for statistical calculation and analysis. Sampling was recorded every 10 fs during the calculation.