tetracene 分子在Ru(1010)表面的吸附结构及其电子态研究

利用紫外光电子能谱(UPS)、角分辨紫外光电子能谱(ARUPS)和扫描隧道显微镜(STM)等方法研究了tetracene分子在Ru(1010)表面上吸附的电子态，吸附位置和吸附取向.UPS实验显示，与tetracene分子有关的光电子谱峰在费米能级以下2.1, 3.5, 4.8, 6.0, 7.1和9.2 eV处；ARUPS 结果表明，tetracene分子的分子平面基本平行于衬底表面；从STM图像中可以看到tetracene分子的长轴沿［0001］和［1210］两个晶向.基于密度泛函理论的从头算计算证实了上述结论.当分子长轴沿［0001］晶向时，分子中心位置在衬底表面的“短桥位”上，当分子长轴沿［1210］晶向时，分子中心位置在衬底表面的“四原子中心空位”上. 关键词： tetracene分子 Ru(1010)表面 吸附结构 吸附电子态

Electronic and structural investigation of tetracene adsorbed on Ru(1010) surface

The electronic states of tetracene adsorbed on Ru (1010) surface as well as their adsorption sites and directions has been studied by using ultraviolet photoelectron spectroscopy (UPS), angle-resolved ultraviolet photoelectron spectroscopy (ARUPS) and scanning tunneling microscopy (STM). The UPS measurements show that the six peaks from the tetracene are 2.1, 3.5, 4.8, 6.0, 7.1 and 9.2 eV below the Fermi level. The ARUPS measurements suggest that the plane of tetracene molecule is parallel to the Ru(1010) surface. The STM image shows that the tetracene molecule is adsorbed on Ru (1010) surface with its longer axis lying in the direction of either ［0001］ or ［1210］. The adsorption structure was confirmed with an ab initio calculation based on density functional theory (DFT). The short-bridge site and the hollow site are the most favorable sites when the molecule has its longer axis oriewted along ［0001］ and ［1210］, respectively.