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在密度泛函理论的框架下,采用嵌入点电荷簇模型研究了O_2在具有氧缺陷和镁缺陷MgO(001)表面上的吸附.用电荷自洽的方法确定了点电荷的值.计算结果表明,O_2倾向吸附在具有氧缺陷的MgO(001)表面上.通过和我们近期研究过的O_2在低配位的边、角上吸附结果相比较,发现具有氧缺陷的MgO(001)表面更加有利于O_2的吸附和解离.Mulliken电荷分析表明,电荷由底物向吸附的O_2反键轨道上转移是导致O_2键强削弱的主要原因.势能曲线表明,O_2在具有氧缺陷的MgO(001)表面上发生解离所需要克服的能垒比在角阳离子端发生解离所需克服的能垒有大幅度降低.
In the framework of the density functional theory, the adsorption of O_2 on the MgO (001) surface with oxygen defects and magnesium defects was studied by using the embedded-point charge-cluster model. The value of the point charge was determined by the self-consistent charge method. , O 2 tends to adsorb on the surface of MgO (001) which has oxygen deficiency.Comparing with the results of the adsorption of O 2 on the side and the corner of our recent study, it is found that the surface of MgO (001) Which is conducive to the adsorption and dissociation of O 2 .Mulliken charge analysis shows that the charge transfer from the substrate to the adsorbed O 2 antibonding orbital is the main reason for the strong weakening of the O 2 bond.The potential energy curve shows that O 2 is adsorbed on the surface of MgO (001) The energy barrier to overcome in the event of dissociation is significantly lower than the energy barrier overcome in the event of dissociation at the cations.