THEORETICAL STUDY ON THE INTERMOLECULAR INTERACTIONS OF 1,1-DIAMINO-2,2-DINITROETHYLENE WITH NH3 AND H2O

Density Functional Theory (DFT) and dispersion-corrected density functional theory (DFT-D) were used to study the intermolecular interactions of 1,1-diamino-2,2-dinitroethylene FOX-7/NH3and FOX-7/H2O supermolecules. The geometries optimized from DFT and DFT-D methods are similar.Six optimized supermolecules were characterized to be local energy minima on potential energy surfaces without imaginary frequencies. The intermolecular interaction energy (binding energy) was calculated with basis set superposition error (BSSE) correction. The largest corrected intermolecular interaction energy is FOX-7/NH3 (-43.76 kJ×mol-1), indicating that the interaction between FOX-7 and NH3 is stronger than that of FOX-7/H2O. The same conclusion is obtained from the studies on the infrared spectrum and frontier orbitals.