A Transferable Intermolecular Potential for Nitramine Crystals
Final rept. Jan-Aug 1998
ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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We have analyzed the transferability of a previously proposed Buckingham repulsion.dispersion intermolecular potential for the explosive hexahydro-l,3,5-s-trinitro-l,3,5-s-triazine RDX Sorescu, D. C., B. M. Rice, and D. L. Thompson, Journal of physical Chemistry B, vol. 101, p. 798, 1997 to predict the crystal structures within the approximation of rigid molecules of a database of 30 nitramines. These include acyclic, monocyclic, and polycyclic molecules. It is shown that the proposed potential model is able to accurately reproduce the crystallographic structures and lattice energies where available of these crystals. For the majority of these crystals, the best agreement with experimental structural and energetic data is obtained in those cases when the electrostatic charges have been determined using ab initio methods that include electron correlations effects namely MP2 and B3LYP. The use 0 the electrostatic charges calculated at the Hartree-Fock level results in large deviations of the predicted lattice energies from the experimental values. The deviations of the lattice energies can be significantly decreased by scaling the electrostatic charges with a constant factor.
- Physical Chemistry
- Ammunition and Explosives