Theoretical investigation of impact sensitivity of nitrogen rich energetic salts

Abstract

The higher impact sensitivity of many energetic materials has become one of the major obstacles which diminishes its wide range of applications in various fields. Salt formation is an effective approach that enhances the stability of the molecules towards impact. In this study quantum mechanical calculations have been employed in order to predict the impact sensitivity trends for the series of nitrogen rich energetic salts: 3-Amino-1,2,4(4H)-oxadiazol-5-one (AOD) and 4-Nitramino-1,2,4-Triazole (NRTZ). Quantum mechanically derived criteria, namely, HOMO-LUMO energy gap, ratio of the bond dissociation energy to molecular total energy, the electrostatic potential at bond mid-point, bond topological parameters were computed, and the quality of results are assessed against experimental BAM fall hammer test results. Several sets of DFT functionals and basis sets were tested to identify the best level of theory for the selected nitrogenous salts. The results demonstrated an excellent qualitative prediction of the impact sensitivity by using CAMB3LYP/6-31G(d)/IEFPCM = water level of theory. Hence, quantum mechanical predictions are an ideal preliminary approach to design advanced energetic salts based on AOD and NRTZ with enhanced stability prior to the synthesis, which facilitates reducing the great cost and risk to safety.