NO在稀有金属钇表面的吸附行为

以往的理论在预测六方结构(HCP)金属的表面能时，计算值与实验值存在较大误差.鉴于此，本文首先用一种较为合理的方法精准地预测了稀有金属钇(Y)(0001)面的表面能，计算值(1.141 J/M²)与实验值(1.125 J/M²)吻合的很好.随后，系统研究了NO小分子在Y(0001)面不同位置(空位、桥位和端位)的吸附行为.结果表明:空位(H1)表现出了良好的吸附能力，吸附能超过了5eV，同时N-O键长伸长量超过了24%，此时，NO分子几乎平行地吸附于Y(0001)表面.所有的吸附位置的N-O分子伸长量范围为0.2?-0.42?.这种伸长量明显超过了NO在其它金属表面时的计算结果.

The rare metal yttrium adsorbing NO molecule

In terms of the theoretical calculation of surface energy for the rare metal Yttrium (Y) with hexagonal close-packed structure, earlier reports failed to predict the precise results. Here, a logical method was employed to evaluate the surface energy of Y (0001) surface, and the obtained value (1.141J/M2) is well consistent with the experimental outcome (1.125J/M2). Subsequently, the behaviors of Y (0001) surface adsorbing NO at different sites, i. e. hollow (H1, H2, and H3), bridge (B), and top (T) sites were investigated theoretically. It was found that hollow site H1 has a great ability to adsorb NO molecule, of which the adsorption energy is over 5 eV. Meanwhile, a remarkable elongation of N-O distance (about 24%) at H1 site is observed, coupled with the NO molecule being at the surface parallelly. A variation range of N-O elongation for all adsorption sites is from 0.2 Å (T) to 0.42 Å(H1). This theoretical extension of NO at H1 site is obviously more than those of NO being adsorbed on other transition metal surface.