Alternatives to legacy munitions and explosives, materials that feature increased stability against external stimuli without compromising their energetic yields are currently being developed. The environmental interactions of such energetic materials need to be addressed, especially as their use becomes more widespread. In order to explore such compounds with environmental influences in mind, we assess the electronic structure and properties of these insensitive munitions (IMs) compounds in modeled hard water using both theory and experiment. To model the IMs in hard water, we have used density functional theory with the M06-2X functional and the 6-311 + G(d,p) basis set with explicit water molecules to capture features like hydrogen bonding, implicit solvent to incorporate bulk water effects, and select ions that would be present in natural water. We ensured the nature of the potential energy surfaces of optimized geometries through vibrational frequency calculations under the harmonic approximation. Several electronic properties, such as oxidation and reduction potentials and electron affinity and ionization potential, for each system are presented. Additionally, cyclic voltammetry experiments were performed, and obtained results were compared with quantum chemical predictions. The experimental reduction potentials are found to be in good agreement with the predicted results. Overall, the reduction potentials predicted by density functional theory for the IM-ion-water complexes are shifted compared with the corresponding isolated munition such that reduction or oxidation would be more facile in the presence of water and ions.

中文翻译：

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一种综合量子化学和实验方法，用于探索与散装水中离子相互作用的不敏感弹药的结构和特性

目前正在开发替代传统弹药和炸药的材料，这些材料对外部刺激具有更高的稳定性，而不会影响其能量产出。需要解决此类含能材料的环境相互作用问题，尤其是随着它们的使用变得更加广泛。为了在考虑环境影响的情况下探索此类化合物，我们使用理论和实验评估了这些不敏感弹药 (IM) 化合物在模拟硬水中的电子结构和特性。为了模拟硬水中的 IM，我们使用了具有 M06-2X 泛函和 6-311 + G(d,p) 基组的密度泛函理论以及显式水分子来捕获诸如氢键、隐式溶剂以合并大量水效应，并选择天然水中存在的离子。我们通过谐波近似下的振动频率计算来确保优化几何形状的势能面的性质。介绍了每个系统的几种电子特性，例如氧化和还原电位以及电子亲和力和电离电位。此外，还进行了循环伏安实验，并将所得结果与量子化学预测进行了比较。发现实验还原电位与预测结果非常一致。总体而言，与相应的孤立弹药相比，IM-离子-水复合物的密度泛函理论预测的还原电位发生了变化，因此在水和离子存在的情况下，还原或氧化更容易。