Shock wave induced decomposition of RDX: time-resolved spectroscopy

Area of Science:

• Materials Science
• Chemical Physics
• Spectroscopy

Background:

• Understanding the decomposition of energetic materials like RDX under shock conditions is crucial for safety and performance.
• Previous studies have explored RDX behavior, but detailed mechanisms under specific shock orientations require further investigation.

Purpose of the Study:

• To investigate the chemical decomposition pathways of RDX crystals subjected to shock compression along the [111] orientation.
• To identify the critical stress threshold and spectral characteristics associated with RDX decomposition intermediates.

Main Methods:

• Time-resolved optical spectroscopy was employed to monitor shock-induced emission from RDX crystals.
• Experiments were conducted at peak stresses ranging from 7 to 20 GPa along the [111] crystal orientation.

Main Results:

• Shock-induced emission was observed between 350-850 nm, indicating decomposition intermediates.
• A clear threshold for emission response was identified at approximately 10 GPa.
• Above 10 GPa, a long-wavelength emission component, attributed to NO2 radicals, dominated, and spectrally integrated intensity increased significantly.

Conclusions:

• The study establishes a critical stress threshold (around 10 GPa) for accelerated chemical decomposition of shocked RDX.
• The formation of NO2 radicals and subsequent bimolecular reactions are identified as key mechanisms driving decomposition above this threshold.
• These findings provide experimental data to support the development of detailed decomposition mechanisms for shocked RDX.