Theoretical investigations on CL-20/ANTA co-crystal explosive via molecular dynamics method

Context The study of CL-20 co-crystal has always been a focal point within the field of energetic material modification. In this study, we employed a combination of density functional theory and molecular dynamics simulations to investigate the properties of hexanitrohexaazaisowurtzitane (CL-20)/3-amino-5-nitro-1,2,4-triazole (ANTA) with different molar ratios ranging from 4:1 to 1:4. Additionally, EXPLO-5 software utilized 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 co-crystal. The most likely molar ratio for co-crystal formation was 1:1, and the main driving forces for co-crystal formation were electrostatic force, dispersion force, and van der Waals force. The co-crystal explosive exhibited moderate sensitivity and excellent mechanical properties. Furthermore, the co-crystal 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 co-crystal 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. Conducted MD simulation under the NPT ensemble for a total simulation duration 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.