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The crystal structure of the high-pressure phase of hexahydro-1,3,5-trinitro-1,3,5-triazine ([gamma]-RDX) is investigated by using infrared spectroscopy and powder X-ray diffraction measurements followed by Rietveld refinements using a diamond anvil cell (DAC). The molecular structure of the [gamma] phase has displayed the same conformation as that of the alpha phase, but the torsion angles of N-N[O.sub.2] changed marginally.

Plane-wave ab initio calculations based on the density function theory (DFT) method with the ultrasoft pseudopotentials are used to study the structural and electronic properties of energetic crystal TNAD (trans-1,4,5,8-tetranitro-1,4,5,8-tetraazadecalin). The thermal expansion coefficients calculated for the crystal has shown anisotropic behavior with the largest expansion along the b axis.

An experimental electron density was determined to understand magnetic interaction pathways in a purely organic free radical, m-(ethynyl)pyridyl nitronyl nitroxide, using accurate X-ray diffraction measurements. The intermolecular contacts were characterized by a topological analysis of the experimental electron density.

Microscopic simulations are used to study the thermodynamic and chemical properties of inert nitromethane explosive on a Hugoniot curve. The Crussard curve of detonation properties is calculated.

The dominant factors governing the impact sensitivity ([H.sub.50]) of nitrobenzenes and saturated nitro compounds are analyzed. The cross-validation results have shown the quantitative model to be stable, which might also be a useful tool for the design of high-energy-density materials.

The synthesis, crystal structure, and magnetic properties of newly designed napth [2,3-d] imidazol-2-yl nitronyl nitroxide are described to examine the effects of ring extension on the crystal packing and magnetic behavior. The results conclude that space interaction between the O atoms of the nitroxide is predominant, by considering the identical magnetic data between the NH nondeuterated and deuterated samples.