Thin films of solid ammonia (NH(3) and ND(3)) have been characterized using low temperature (25-110 K) Fourier-transform infrared (FTIR) spectroscopy, and the three solid phase (amorphous, metastable, and crystalline) spectra are reported. This work has been motivated by confusion in the literature about the metastable and crystalline phases as a result of an early erroneous report by Staats and Morgan [(J. Chem. Phys. 31, 553 (1959)]. Although the crystalline phase has subsequently been reported correctly, the metastable phase has not been described in the literature in detail. The unique characteristics of the metastable phase, reported here for the first time, include multiple peaks in the nu(2) and nu(3) regions and peak intensities that are dependent on the deposition temperature. This behavior may be the result of (a) preferential molecular orientations in the solid, or (b) exciton splitting due to different crystal shapes in the solid. The amorphous and metastable phases of deuterated ammonia are also reported for the first time.

Background Charcot neuroarthropathy (CN) of the ankle and hindfoot (Sanders/Frykberg Type IV) is challenging to treat surgically or nonsurgically. The deformities associated with ankle/hindfoot CN are often multiplanar, resulting in sagittal, frontal and rotational malalignment. In addition, shortening of the limb often occurs from collapse of the distal tibia, talus and calcaneus. These deformities also result in significant alterations in the biomechanics of the foot. For example, a varus ankle/hindfoot results in increased lateral column plantar pressure of the foot, predisposing the patient to lateral foot ulceration. Collapse of the talus, secondary to avascular necrosis or neuropathic fracture, further accentuates these deformities and contributes to a limb-length inequality.

Level III, retrospective, case-control study.

Prognostic, Level III: Case Control.