Microscopic Mechanism of Impact Sensitivity in Typical Energetic Materials: From Electronic Structure to Vibration...

Energetic materials are widely used in many fields and their safety is of great concern, while the factors affecting impact sensitivity and the mechanisms of chemical bond breaking and energy transfer are still unclear. In this study, first-principles calculations were employed to elucidate the electronic and vibrational characteristics of TATB and LLM-105. Both materials are indirect semiconductors. However, LLM-105 exhibits a markedly smaller band gap and more localized nitro-antibonding conduction states, suggesting enhanced electronic excitability and potential trigger-bond activation. Phonon analysis reveals dense nitro-dominated vibrational modes in the doorway frequency region (200-700 cm^-1), particularly in LLM-105, which may favor vibrational energy localization. In contrast, the larger band gap, delocalized conduction states, and extensive hydrogen-bonding network of TATB promote electronic and phononic energy delocalization, consistent with its lower sensitivity. These findings demonstrate that coupled electronic and vibrational effects govern stability differences in energetic materials and provide a theoretical framework for sensitivity modulation.