Na(110)和Na_2O(111)表面弛豫的研究

Study of Relaxation of Na(110) and Na_2O(111) Surfaces

研究Na(110)和Na_2O(111)表面的原子结构是表面科学基础理论工作之一,它在光电,光声和频标器件以及超晶格,微结构和纳米等实用技术方面都具有重要意义。 Andersson等在Ni衬底的(100)表面上沉积金属Na,得到了体心立方(bcc)结构,并观测其(110)表面的LEED谱。然后将Na氧化得反荧石型的晶相,并观测其(111)表面的LEED谱。我们采用低能电子衍射的能带近似法,分别计算了Na(110)表面的(00),(10)和(01)束以及Na_2(111)表面的(00),(10)和(11)束的LEED谱,经理论计算与观测值的比较,得到的Na(110)表面原子层间距d=2.91±0.01(收缩3.4%±0.01);Na_2O(111)表面的三个原子层间距d_1=1.17±0.01(膨胀46.3%±0.01),d_2=1.61±0.01(膨胀0.63%±0.01),d_3=0.86±0.01(膨胀7.5%±0.01)。

We have studied the relaxation of Na(110) and Na_2O(111) surfaces with LEED, and found that the best agreement between theory and experiment in such a structure, the surface layer distance d=2.91±0.01A(contracted 3.4%±0.01A) [for Na(110)]; and the three atomic surface layer distances d_1=1.17±0.01A(expanded 46.3%±0.01A), d_2=1.61±0.01A(expanded 0.63%±0.01A) and d_3=0.86±0.01A(expanded 7.5%±0.01A) [for Na_2O(111)].