First-principles study of electronic structure, absorption spectra, and thermodynamic properties of crystalline 1H-tetrazole and its substituted derivatives

Periodic density functional theory has been used to study the electronic structure, absorption spectra, and thermodynamic properties of crystalline 1H-tetrazole and its substituted derivatives: 5-methyl-1H-tetrazole, 5-azido-1H-tetrazole, and 5-amino-1H-tetrazole. The aim is to investigate substitution effects on the electronic structure and properties of the 1H-tetrazole crystal. The electronic structure was analyzed by examining the density of states, charges, and bond orders of the four crystals. We also show their absorption coefficients and thermodynamic functions including entropy, heat capacity, enthalpy, and free energy. Finally, we made an attempt to correlate the impact sensitivity of the four crystals with their band gaps.