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在超高真空条件下,采用电子束阻挡势技术测量固体表面功函数连续变化,并与AES,TDS等手段相配合,研究了氧在Ag和Ag-Pd合金表面的吸附和脱附动力学。结果表明,在Ag和Ag-Pd合金表面的两种不同的氧吸附态,具有相反的电荷转移效应,未解离的分子态吸附降低了表面功函数,而解离的原子态氧吸附使表面功函数明显升高。与纯银相比,氧在银钯合金表面吸附具有较小的粘附系数和较大的偶极矩。银钯合金组成变化时功函数和AES的连续测量表明,表面结构从无序向有序转变和表面银偏析均为功函数降低过程。
Under ultra-high vacuum conditions, the continuous variation of work function of solid surface was measured by electron beam blocking potential technique. The adsorption and desorption kinetics of oxygen on the surface of Ag and Ag-Pd alloy were studied with AES and TDS. The results show that the two different oxygen adsorption states on the Ag and Ag-Pd alloy surfaces have the opposite charge transfer effect, and the non-dissociated molecular adsorption decreases the surface work function, while the dissociated atomic oxygen adsorption causes the surface Work function increased significantly. Compared with pure silver, oxygen in silver palladium alloy surface adsorption has a smaller adhesion coefficient and larger dipole moment. The work function of the Ag-Pd alloy and the continuous measurement of AES show that the surface structure changes from disordered to ordered and the silver segregation on the surface are the work function reduction processes.