Intermolecular Energy Transfer Dynamics at a Hot-Spot Interface in RDX Crystals
Kaushik Joshi1, Martin Losada2, Santanu Chaudhuri1
1Applied Research Institute, University of Illinois at Urbana-Champaign , Champaign, Illinois 61820, United States.
The Journal of Physical Chemistry. A
|January 8, 2016
Summary
This study explores vibrational energy transfer in energetic solids far from equilibrium. It reveals new mechanisms involving small molecule collisions and bending modes at high-temperature interfaces, differing from standard phonon models.
Area of Science:
- Chemical Physics
- Materials Science
- Computational Chemistry
Background:
- Phonon-mediated vibrational up-pumping models assume equilibrium conditions.
- Dynamic processes far from equilibrium in energetic solids remain poorly understood.
- Understanding decomposition reactions in energetic materials is crucial for safety and performance.
Purpose of the Study:
- Investigate vibrational energy transfer mechanisms under non-equilibrium conditions in RDX crystals.
- Explore dynamics at high-temperature interfaces during decomposition.
- Compare simulation results with existing phonon-based models.
Main Methods:
- Classical molecular dynamics (MD) simulations were employed.
- Both nonreactive and reactive potentials were used to model RDX.
- Simulations focused on reacted and unreacted zones under temperature gradients.
Main Results:
- Energy transfer rates were evaluated based on temperature differences and RDX layer dimensions.
- Vibrational up-pumping mechanisms at hot-spot interfaces differ significantly from standard phonon models.
- High-frequency vibrations are up-pumped via small molecule collisions and bending modes.
Conclusions:
- Standard phonon-based models are insufficient for describing non-equilibrium dynamics in energetic solids.
- New mechanisms involving molecular collisions and specific vibrational modes are identified.
- Findings provide insights into the decomposition pathways of energetic materials like RDX.
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