摘要
本文采用EHMO方法计算了Ni_7,Ni_6Cu,Ni_6Mn,Ni_4Mn_3,Ni_4Cu_3原子簇和H_2分子所构成的解离吸附体系,计算结果表明:杂原子(Cu,Mn)处于Ni(111)面3CN的顶位,对H_2分子在Ni表面的解离吸附起相互协同加强的作用;处于侧位,则起相消的作用;随掺杂的原子的不同而又有所不同:杂原子Cu明显强于杂原子Mn的作用,随金属对H_2分子吸附能力的增强(R_e缩小,E_a增大),电子向H_2的反键轨道上转移,使H-H间键削弱,直至解离,关于这些现象本文从其电子结构以及成键方式等方面做了解释.
The extended Huckel molecular orbital method was used to gain an insight into the interactions of H_2 with seven atom clusters simulating (111) crystal surfaces of Ni and its alloys(Ni_6Cu, Ni_6Mn, Ni_4Cu_3, Ni_4Mn_3). Based on our calculation results, we could make the following conclusions: (1) Impure atom(Cu, Mn) were located on the top Ni (111) surface 3CN adsorpt position, the adsorption energy(E_α) increases, and if in side of it, the adsorption energy decreases. (2) With the distance between H_2 and the clusters shortened, the ability of adsorpted H_2 of the clusters strengthened and the electron transferred from the clusters to σ(?) anti-bonding orbital of H_2.These conclusions are in agreement with experimental facts when available, and they have been explained on the basis of the electronic structure, bonding nature and adsorbed positions.
