Theoretical predictions on the structures and properties for polynitrohexaazaadamantanes (PNHAAs) as potential high energy density compounds (HEDCs)

It is the heated point to make molecular design of high energy density compounds (HEDCs) in the world energy and resource field. However, previous works usually were ended with gas molecular design. On the other hand, most of high energy materials are in agglomerate phase, especially in crystals. In this paper, we make crystal structure predictions for the potential HEDCs, polynitrohexaazaadamantanes (PNHAAs), by choosing appropriate force field using molecular mechanics (MM) method. Based on the ab initio periodic calculations on their predicted packings, their electronic structures (density of states, DOS) and properties, such as sensitivity and thermolysis mechanism were investigated. Besides, we make comparisons between the conclusions drawn from gas and solid calculations. It is most interesting that our calculations predict that 2,4,6,8,9,10-hexanitrohexaazaadamantane may possess better properties than the well-known HEDC ε-CL-20 (hexanitrohexaazaisowurtzitane).