How Do Small Differences in Geometries Affect Electrostatic Potentials of High-Energy Molecules? Critical News from Critical Points

Abstract

The computational design of explosives is becoming very popular since it represents a safe and environmentally friendly way of predicting the properties of these molecules. It is known that positive values of electrostatic potential in the central areas of the molecular surface are a good indicator of the sensitivity of high-energy materials towards detonation. The molecular electrostatic potential is routinely calculated for molecules of explosives using both geometries extracted from crystal structures, and computationally optimized geometries. Here we calculated and compared values of positive electrostatic potential in the centers of five classical high-energy molecules for geometries extracted from different crystal structures and theoretically optimized geometries. Density functional theory calculations performed at M06/cc-PVDZ level showed that there are significant differences in the values of electrostatic potentials in critical points obtained for different geometries of the same high-energy molecules. The study also showed that there was an excellent agreement in the values of electrostatic potentials calculated for optimized geometry of 1,3,5-trinitrobenzene and geometry of this molecule obtained by neutron diffraction experiments. The results of this study could help researchers in the area of the computational development of high-energy molecules to better design their studies and to avoid the production of erroneous results.