Compounds with a backbone of directly linked nitrogen atoms have high nitrogen concentration and high formation enthalpy. The end product of a propulsion or explosion of these compounds contained mainly molecular nitrogen. Therefore, the study on them as potential environment-friendly propellants and explosives was of great interest recently. In this paper, the ionization potentials of 1H-tetrazole (1), 5-aminotetrazole (2), 1,5-diaminotetrazole (3) and 1,4-bis(1-methyltetrazol-5-yl)-1,4-dimethyl-2-tetrazene (4) were reported, which were recorded by photoelectron spectroscopy. The experiment gave the ionization potentials of the four compounds as 11.22, 9.40, 9.27, 9.18 eV respectively. The UV absorption spectra showed that there was only one absorption band in compounds 1～3, at 193, 216, 218 nm respectively, while compound 4 had two UV absorption bands at 230 and 298 nm.

Key words: high energy material, nitrogen catenation, photoelectron spectroscopy, UV absorption spectroscopy, quantum chemistry calculation