ABOUT US

RESEARCH

RESEARCHERS

REPORTS

SOFTWARE

FACILITIES

EMAIL SERVICES

WIKIS

AuthorA. Pal and R. C. Picu
TitleRotational defects in cyclotrimethylene trinitramine (RDX) crystals
Year2014
JournalTHE JOURNAL OF CHEMICAL PHYSICS
Volume140
PublisherAIP Publishing LLC
AbstractCyclotrimethylene trinitramine (RDX) crystalizes in the orthorhombic α-phase at the ambient pressure and temperature. In principle, the point defects commonly found in monatomic crystals, such as vacancies and interstitials, may exist in RDX as well. However, in molecular crystals one encounters additional point defects associated with the distortion of the molecules. A set of rotational defects are described in this article. These are molecules which are located in the proper positions in the crystal but are rotated relative to the molecules in the perfect crystal, and their ring is slightly puckered. The energetic barriers for defect formation and for their annealing back to the perfect crystal configuration are computed using an atomistic model. It is shown that the formation energy of rotational defects is smaller than the vacancy formation energy. Such defects are identified in the cores of dislocations in RDX and hence their concentration in the crystal is expected to increase during plastic deformation. The importance of such point defects is related to their role in phonon scattering and in dislocationmediated plastic deformation.
PDF File Download