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用量子化学密度泛函理论的B3LYP方法 ,在 6 31+G 水平上按BERNY能量梯度解析全参数优化了HNCO与CX (X =F ,Cl,Br)反应势能面上各驻点的几何构型 ,通过振动频率分析确认了中间体和过渡态 ,内禀反应坐标(IRC)对反应物、中间体、过渡态和产物的相关性予以证实 ,对各驻点进行了零点能校正 (ZPE) ,在此基础上计算了反应能垒 .研究结果表明 ,与HNCO和其它小分子自由基反应不同 ,HNCO与CX自由基反应首先发生分子间H原子迁移 ,随后N与CX的C(1)原子相互靠近成键并生成较稳定的中间体 ,再发生N—C(2 )键的断裂 ,完成N向C(1)上的迁移并进一步解离为产物 .反应按反应物→TS1→IM→TS2→产物通道进行 .反应为放热反应 .
The B3LYP method of quantum chemical density functional theory (DFT) was used to optimize the geometry of each stationary point on the potential energy surface of HNCO and CX (X = F, Cl, Br) at 631 + G by BERNY energy gradient analysis of all parameters The correlations between intermediates and transition states and intrinsic reaction coordinate (IRC) for reactants, intermediates, transition states and products were confirmed by vibrational frequency analysis. Zero Point Correction (ZPE) On this basis, the energy barrier of the reaction was calculated. The results show that, unlike HNCO and other small molecule free radicals, HNCO intermolecular H atom transfer occurs first and then C and C (1) atoms of CX interact with each other Close to the bond and generate more stable intermediates, and then break the N-C (2) bond to complete the migration from N to C (1) and further dissociation into the product. The reaction was carried out according to the reaction product → TS1 → IM → TS2 → product channel reaction is exothermic reaction.