A molecular dynamics method was employed to study the binding energies of the selected crystal planes of the 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane/1,1-diamino-2,2-dinitroethylene (HMX/FOX-7) cocrystal in different molecular molar ratios. Mechanical properties, densities, and detonation velocities of the cocrystals in different ratios were estimated. The intermolecular interactions and bond dissociation energies (BDEs) of the N–NO₂ bond in the HMX:FOX-7 (1:1) complex were calculated using the B3LYP and MP2(full) methods at the 6–311++G (d,p) and 6–311++G(2df,2p) basis sets. Solvent effects on stability are discussed. The results indicate that HMX/FOX-7 cocrystals prefer cocrystalizing in a 1:1 molar ratio, which has good mechanical properties. The N–NO₂ bond becomes strong upon the formation of a complex and the sensitivity of HMX might decrease in cocrystals. The sensitivity change of HMX/FOX-7 originates from not only the formation of intermolecular interaction but also the increment in the N–NO₂ BDE. HMX/FOX-7 cocrystals exhibit good detonation performance and meet the requirements of high-density energetic materials. Solvents with low dielectric constants may be chosen to obtain stable HMX/FOX-7 cocrystals.

Adding an external electric field into an energetic material system can increase the energy but the stability may be reduced. In this paper, the effects of external electric fields on the initiation reaction dynamics of CH₃NO₂ (intermolecular and 1,3-intramolecular hydrogen transferences) were investigated using the MP2/6-311++G(2d,p) and CCSD/6-311++G(2d,p) methods. The results show that, when the external electric field is in the −y-direction of the CH₃NO₂ dimer (perpendicular to the O⋯N⋯N plane), the barriers of intermolecular hydrogen transference are lower than the C–NO₂ bond dissociation energies, leading to a preference for the hydrogen transference path over the C–NO₂ bond dissociation, and the sensitivities are higher than in the absence of an external electric field. However, in the other fields (except for the C–NO₂ bond axis direction with a field strength larger than +0.0060 a.u.), the C–NO₂ bond scission is favored and the sensitivities are almost equal to those in the absence of an external electric field. Although due to many obstacles, at present the proposition of adjusting the explosive sensitivity with external electric field does not make any sense in practice, the external-electric-field effect on explosive sensitivity must arouse intense interest in future.

The clusteroluminescence of poly(cyclic carbonate)s is achieved by the through-space n–n interaction of oxygen atoms, showing molecular weight-dependent emission.