Formation of weakly bound, ordered adlayers of CO on rutile TiO2(110): a combined experimental and theoretical study.
Formation of weakly bound, ordered adlayers of CO on rutile TiO2(110): a combined experimental and theoretical study.
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在金红石 TiO2(110) 上形成弱结合、有序的 CO 吸附层：实验和理论相结合的研究。
作者：
M. Kunat;F. Traeger;D. Silber;H. Qiu;Yuemin Wang;A. Veen;C. Wöll;P. Kowalski;B. Meyer;C. Hättig;D. Marx
采用He原子散射（HAS）、高分辨电子能量损失谱（HREELS）、热脱附谱（TDS）和不同类型的从头算电子结构计算研究了CO在金红石型TiO（2）（110）表面的吸附.实验和理论结果允许提出一个一致的图片，这个相当复杂的吸附质系统。在70 K时，形成具有滑移对称平面的（2x 1）吸附层，每个晶胞包含两个分子，它们相对于表面法线在交替方向上倾斜约20度。对于这种高密度相，理论计算揭示了大量的排斥CO分子之间的相邻的晶格位置，在雅阁与实验TDS数据的详细分析的结果。CO的结合能强烈地依赖于覆盖率和变化之间的0.20 eV的饱和单层和0.36 eV的孤立分子。CO-CO排斥导致约一半的CO分子在70 K以上脱附并形成低密度相。在这些较低的覆盖率下，HAS没有给出有序吸附层的指示。对于CO分子的内部伸缩振动的一个值为273毫电子伏的HREELS确定，在非常好的协议与理论计算。
The adsorption of CO on the rutile TiO(2)(110) surface was investigated using He atom scattering (HAS), high resolution electron energy loss spectroscopy (HREELS), thermal desorption spectroscopy (TDS), and different types of ab initio electronic structure calculations. The experimental and theoretical results allow to put forward a consistent picture for this rather complicated adsorbate system. At 70 K a (2x1) adlayer with a glide symmetry plane is formed, containing two molecules per unit cell which are tilted in alternate directions by about 20 degrees relative to the surface normal. For this high density phase, the theoretical calculations reveal a substantial repulsion between CO molecules on neighboring lattice sites, in accord with the results of a detailed analysis of the experimental TDS data. The CO binding energy depends strongly on coverage and varies between 0.20 eV for the saturated monolayer and 0.36 eV for isolated molecules. The CO-CO repulsion leads to the desorption of about half of the CO molecules above 70 K and the formation of low density phases. HAS gave no indication of ordered adlayers at these lower coverages. For the internal stretching vibration of the CO molecules a value of 273 meV was determined by HREELS, in very good agreement with the theoretical calculations.