Welcoming 2006 with a bang. Or the molecular foundations for a bang, anyway. In the Journal of Physical Chemistry A (J. Phys. Chem. A 2006, 110, 1951). The experimental results were provided by TeraView, Ltd., solid-state calculations with DMol3 from Accelrys.
D. G. Allis, D. A. Prokhorova, and T. M. Korter
Abstract: The experimental solid-state terahertz (THz) spectrum (3-120 cm-1) of the beta-crystal form of the high explosive octahydro – 1,3,5,7 – tetranitro – 1,3,5,7 – tetrazocine (HMX) has been analyzed using solid-state density functional theory calculations. Various density functionals (both generalized gradient approximation and local density approximation) are compared in terms of their abilities to reproduce the experimentally observed solid-state structure and low-frequency vibrational motions. Good-to-excellent agreement between solid-state theory and experiment can be achieved in the THz region where isolated-molecule calculations fail to reproduce the observed spectral features, demonstrating a clear limitation of using isolated-molecule calculations for the assignment of THz frequency motions in molecular solids. The deficiency of isolated-molecule calculations is traced to modification of the molecular structure in the solid state through crystal packing effects and the formation of weak C-H…O hydrogen bonds.