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Initial decomposition of the condensed-phase β-HMX under shock waves: molecular dynamics simulations
Ni-Na Ge1, Yong-Kai Wei, Guang-Fu Ji
1National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, Chinese Academy of Engineering Physics, Mianyang 621900, China.
The Journal of Physical Chemistry. B
|October 20, 2012
Summary
Quantum simulations reveal shock wave impact velocity dictates octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) decomposition. Lower velocities break N-NO(2) bonds, while higher velocities initiate C-H bond dissociation, impacting energetic material development.
Area of Science:
- Computational chemistry
- Materials science
- Chemical kinetics
Background:
- Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) is a crucial energetic material.
- Understanding its decomposition under shock loading is vital for safety and performance.
Purpose of the Study:
- To investigate the initial chemical processes of condensed-phase HMX under varying shock wave velocities.
- To elucidate the atomistic mechanisms governing HMX decomposition.
Main Methods:
- Quantum-based multiscale simulations were performed.
- A self-consistent charge density-functional tight-binding (SCC-DFTB) method was utilized.
Main Results:
- At 8 km/s impact, N-NO(2) bond breaking initiates HMX decomposition.
- At 11 km/s, high pressure suppresses N-NO(2) cleavage; C-H bond dissociation becomes dominant.
- Decomposition involves five-membered ring formation and hydrogen transfer.
Conclusions:
- The initial decomposition pathway of shocked HMX is strongly dependent on impact velocity.
- These findings provide atomistic insights into HMX shock response.
- Results have significant implications for the design and application of energetic materials.
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