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从理论上研究铀氧(碳)化产物的电子结构和氧化过程中电子的转移过程,从微观上揭示铀表面氧化反应初始阶段的机理,对探讨金属铀表面防腐的方法有重要意义。用量子化学从头计算(ab initio)方法,计算了铀、氧和碳三元体系气态原子和分子的优化构型、总能量、振动频率和成键情况。并在单点能计算的基础上构筑了铀与CO相互作用的势能面。计算的铀氧化物和碳化物优化构型和振动频率同现有的实验数据符合较好。U5f在铀与氧或碳的键合中起着重要作用。计算结果说明CO在铀上的吸附属于解离吸附,而且,铀更倾向于从碳端与CO相互作用,势能面分析结果也说明了这点。同时,也证明了铀与CO相互作用的初始产物有UCO,UC和CUO等。
It is of great significance to study the electronic structure of uranium (carbonized) products and the electron transfer process in the process of oxidation, revealing the mechanism of the initial stage of uranium surface oxidation reaction microscopically. Using ab initio method, the optimized configuration, total energy, vibrational frequency and bonding of gaseous atoms and molecules of uranium, oxygen and carbon ternary systems have been calculated. Based on the single-point energy calculation, the potential energy surface of interaction between uranium and CO is constructed. Calculated uranium oxide and carbide optimization configuration and vibration frequency with the existing experimental data in good agreement. U5f plays an important role in the bonding of uranium to oxygen or carbon. The calculated results show that the adsorption of CO on uranium belongs to dissociative adsorption. Moreover, uranium is more likely to interact with carbon from the carbon end. The analysis of potential energy surface also shows this point. At the same time, it is also proved that the initial products of uranium and CO interaction are UCO, UC and CUO.