Theoretical Study on the High Energy Density Compound Hexanitrohexaazatricyclotetradecanedifuroxan

Density functional theory (DFT) has been employed to study the molecular geometries, electronic structures, infrared (IR) spectra, and thermodynamic properties of the high energy density compound hexanitrohexaazatricyclotetradecanedifuroxan (HHTTD) at the B3LYP/6-31G** level of theory. The calculated results show that there are four conformational isomers (α, β, γ and δ) for HHTTD, and the relative stabilities of four conformers were assessed based on the calculated total energies and the energy-gaps between the frontier molecular orbitals. The computed harmonic vibrational frequencies are in reasonable agreement with the available experimental data. Thermodynamic properties derived from the IR spectra on the basis of statistical thermodynamic principles are linearly correlated with the temperature. Detonation performances were evaluated by using the Kamlet-Jacobs equations based on the calculated densities and heats of formation. It was found that four HHTTD isomers with the predicted densities of ca. 2 g·cm⁻³, detonation velocities near 10 km·s⁻¹, and detonation pressures over 45 GPa, may be novel potential candidates of high energy density materials (HEDM). These results may provide basic information for the molecular design of HEDM.