无序二元合金（NixCu1－x）不同解理面上O吸附对Cu偏析的影响

应用计算机编程构造出了存在和不存在表面偏析的无序二元合金Ni_xCu_1-x (x=0.4)(１００)表面及(１１０)表面的原子集团模型，然后按覆盖度θ=0.5，构造 出了O吸附后的原子集团模型，应用Recursion方法计算了O在Ni_xCu_{1-x(存在偏析和不存在偏析时)无序二元合金(１００)和(１１０)表面吸附的电子结构.由此 得出：1)O吸附使合金表面态密度峰降低，带宽加宽，并且表面Ni原子的d电子与吸附质O原 子的s，p电子的共价作用比Cu更强烈；2)O吸附在NixCu1-x(x=0.4) (１１０)表面比(１００)表面更稳定；3)O的吸附抑制了Cu在表面富集，且这种作用主要表 现在表面一层. 关键词： 化学吸附 表面偏析 Recursion方法 态密度}

Influence of O adsorbed on different surfaces of NixCu1-x on the segregation of Cu

The atomic structural models of the(100) and (110) surface of the Ni_x Cu_1-x disordered binary alloy were set up when surface segregation is considered or not by computer programming.Then the models of the chemisorption of O on both surfaces were set up with the coverage θ=0.5. The electronic struc ture of O chemisorbed on the (100) and (110) surfaces of the Ni_xCu1-x disordered binary alloy was calculated (considering and not consider ing the segregation).The calculated results show that (1) the chemisorption lowe rs the surface density of states of the disordered binary alloy,the energy band is widened, and the covalent bonds between the d electron of Ni and the s and p electron of O are stronger than that of Cu, (2) the O adsorbed on the (110) surf ace is more stable than on the (100) surface, and (3) the chemisorption of O on the surface restricts the surface segregation of Cu and this kind of influence i s obvious at the first layer.