Molecular Packing and Molecular Dynamics Study of the Transferability of a Generalized Nitramine Intermolecular Potential to Non-Nitramine Crystals

摘要

We have analyzed the transferability of a previously proposed intermolecular potential for nitramine crystals to reproduce the experimentally determined crystal structures (within the approximation of rigid molecules) of 51 nitro compounds. These compounds include different types of acyclic, monocyclic, and polycyclic molecules. It is shown that this potential model accurately reproduces the experimentally determined crystallographic structures and lattice energies for the majority of these crystals. Further testing of the proposed intermolecular potential has been done by performing isothermal- isobaric molecular dynamics (MD) simulations over the temperature range 100-450 K, at atmospheric pressure, for the monoclinic phase of the 2,4,6- trinitrotoluene (TNT) crystal and for the polymorphic phase I of the pentaerythritol tetranitrate (PETN I) crystal. In each case, the results show that throughout the MD simulations, the average structures of the crystals maintain the same space group symmetry as the one determined experimentally, and there is a good agreement between the calculated crystallographic parameters and the experimental values.