Understanding the structural, geometrical, and chemical changes that occur after an electronic excitation is essential to elucidate the inherent mechanism of nitro explosives. Herein, relaxed structures of typical nitro explosives in the lowest singlet excited state are investigated using time-dependent density functional theory. During the excitation process, the nitro group is activated and relaxes via geometrical change. The five explosives RDX, HMX, CL-20, PETN, and LLM-105 exhibit similar relaxed structures, and the impact sensitivity is related to their excitation energy. High-sensitivity δ-HMX has a lower excitation energy for relaxed structure than β-HMX. This study offers novel insight into energetic materials.

了解电子激发后发生的结构，几何和化学变化对于阐明硝基炸药的内在机理至关重要。在本文中，使用时变密度泛函理论研究了处于最低单重态激发态的典型硝基炸药的弛豫结构。在激发过程中，硝基被激活并通过几何变化而松弛。五种炸药RDX，HMX，CL-20，PETN和LLM-105表现出相似的弛豫结构，并且撞击灵敏度与它们的激发能有关。高灵敏度的δ-HMX与β-HMX相比，对于松弛结构具有较低的激发能。这项研究为高能材料提供了新颖的见解。