Theoretical Study on CL-20-Based Cocrystal Energetic Compounds in an External Electric Field

Area of Science:

• Computational Chemistry
• Materials Science
• Energetic Materials

Background:

• External electric fields can influence the stability and sensitivity of energetic materials.
• Understanding these effects is crucial for the safe handling and application of cocrystal energetic materials.
• Cocrystals offer tunable properties compared to single energetic compounds.

Purpose of the Study:

• To investigate the relationship between external electric fields and the sensitivity of CL-20/BTF, CL-20/DNP, and CL-20/MDNT cocrystals.
• To elucidate the underlying molecular mechanisms governing field-induced sensitivity changes.

Main Methods:

• Density functional theory (DFT) calculations were performed using B3LYP-D3/6-311+G(d,p) and M062X-D3/ma-def2 TZVPP levels.
• Key properties calculated include frontier molecular orbital energy gaps, Atoms in Molecules (AIM) electron densities, N-NO2 bond dissociation energies (BDEs), and electrostatic potentials (ESPs).
• Impact sensitivity (H50) and nitro group charges (QNO) were also analyzed.

Main Results:

• Smaller highest occupied molecular orbital-lowest unoccupied molecular orbital gaps, BDEs, and impact sensitivity (H50) correlate with increased sensitivity in positive electric fields.
• Lower local positive electrostatic potentials (Vs,max) enhance stability in negative electric fields.
• Sensitivity decreases in negative electric fields with increasing negative nitro group charges.

Conclusions:

• External electric fields demonstrably modulate the sensitivity of CL-20 based cocrystals.
• Molecular descriptors like energy gaps, BDEs, ESPs, and nitro group charges are key indicators of sensitivity changes under electric fields.
• Changes in bond lengths, AIM electron densities, and nitro group charges show strong correlation with applied electric field strengths.