Intermolecular Energy Transfer Dynamics at a Hot-Spot Interface in RDX Crystals
| Autor: | Kaushik Joshi, Martin Losada, Santanu Chaudhuri |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
010304 chemical physics
Phonon Chemistry Intermolecular force Non-equilibrium thermodynamics Nanotechnology 010402 general chemistry 01 natural sciences 0104 chemical sciences Crystal Temperature gradient Molecular dynamics Chemical physics Lattice (order) 0103 physical sciences Physical and Theoretical Chemistry Chemical decomposition |
| Zdroj: | The Journal of Physical Chemistry A. 120:477-489 |
| ISSN: | 1520-5215 1089-5639 |
| DOI: | 10.1021/acs.jpca.5b06359 |
| Popis: | The phonon mediated vibrational up-pumping mechanisms assume an intact lattice and climbing of a vibrational ladder using strongly correlated multiphonon dynamics under equilibrium or near-equilibrium conditions. Important dynamic processes far from-equilibrium in regions of large temperature gradient after the onset of decomposition reactions in energetic solids are relatively unknown. In this work, we present a classical molecular dynamics (MD) simulation-based study of such processes using a nonreactive and a reactive potential to study a fully reacted and unreacted zone in RDX (1,3,5-trinitro-1,3,5-triazocyclohexane) crystal under nonequilibrium conditions. The energy transfer rate is evaluated as a function of temperature difference between the reacted and unreacted regions, and for different widths and cross-sectional area of unreacted RDX layers. Vibrational up-pumping processes probed using velocity autocorrelation functions indicate that the mechanisms at high-temperature interfaces are quite different from the standard phonon-based models proposed in current literature. In particular, the up-pumping of high-frequency vibrations are seen in the presence of small molecule collisions at the hot-spot interface with strong contributions from bending modes. It also explains some major difference in the order of decomposition of C-N and N-N bonds as seen in recent literature on initiation chemistry. |
| Databáze: | OpenAIRE |
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