New imidazole-based energetic molecules(1,4-dinitroimidazole,2,4-dinitroimidazole, 1-methyl-2,4-dinitroimidazole, and 1-methyl-2,4,5-trinitroimidazole)are studied both experimentally and theoretically. The NO moleculeis observed as a main decomposition product from the above nitroimidazoleenergetic molecules excited at three UV wavelengths (226, 236, and248 nm). Resolved rotational spectra related to three vibronic bands(0–0), (0–1), and (0–2) of the NO (A 2Σ+← X 2Π) electronic transitionhave been obtained. A unique excitation wavelength independent dissociationchannel is characterized for these four nitroimidazole energetic molecules:this pathway generates the NO product with a rotationally cold (10–60K) and vibrationally hot (1300–1600 K) internal energy distribution.The predicted reaction mechanism for the nitroimidazole energeticmolecule decomposition subsequent to electronic excitation is thefollowing: electronically excited nitroimidazole energetic moleculesdescend to their ground electronic states through a series of conicalintersections, dissociate on their ground electronic states subsequentto a nitro–nitrite isomerization, and produce NO molecules.Different from PETN, HMX, and RDX, the thermal dissociation process(ground electronic state decomposition from the Franck–Condonequilibrium point) of multinitroimidazoles is predicted to be a competitionbetween NO2elimination and nitro–nitrite isomerizationfollowed by NO elimination for all multinitroimidazoles except 1,4-dinitroimidazole.In this latter instance, N–NO2homolysisis becomesthe dominant decomposition channel on the ground electronic state,as found for HMX and RDX. Comparison of the stability of nitro-containingenergetic materials with R–NO2(R = C, N, O) moietiesis also discussed. Energetic materials with C–NO2are usually more thermally stable and impact/shock insensitive thanare other energetic materials with N–NO2and O–NO2moieties. The imidazole aromatic ring also plays an importantrole in improving the stability of these energetic materials. Thus,multinitroimidazoles energetic materials can be of significant potentialfor both civilian and military applications. [ABSTRACT FROM AUTHOR]