Si（001）上乙烯在扭曲悬挂键构型上的位点特异反应性
Site-specific reactivity of ethylene at distorted dangling bond configurations on Si(001)
摘要：
通过密度泛函理论计算，我们报道了乙烯在Si（001）上的吸附和反应能量的差异，以及由氢预覆盖引起的不同悬挂键构型。这有助于理解表面缺陷和预覆盖对有机分子在半导体表面上的反应性的影响。我们的研究结果表明，表面二聚体完全封闭的氢覆盖的原子的反应性是基本上不变的清洁表面相比。这是由我们的扫描隧道显微镜测量证实。与此相反，部分覆盖的表面二聚体的吸附位点的反应性急剧增加。这是由于与清洁表面相比，反应屏障降低了50%以上，这与先前的实验一致。据报道，由分子（乙烯）覆盖的表面原子包围的二聚体上的吸附具有高度降低的反应性，由于空间排斥的中间状态的不稳定的结果，如用周期性能量分解分析（pEDA）量化的。此外，基于统计热力学考虑的吸附吉布斯能的计算方法被应用到该系统。结果表明，分子熵的损失导致吸附态的显着不稳定。
英文摘要：
We report differences in adsorption and reaction energetics for ethylene on Si(001) with respect to different dangling bond configurations induced by hydrogen precoverage as obtained via density functional theory calculations. This can help to understand the influence of surface defects and precoverage on the reactivity of organic molecules on semiconductor surfaces in general. Our results show that the reactivity on surface dimers fully enclosed by hydrogen covered atoms is essentially unchanged compared to the clean surface. This is confirmed by our scanning tunnelling microscopy measurements. On the contrary, adsorption sites with partially covered surface dimers show a drastic increase in reactivity. This is due to a lowering of the reaction barrier by more than fifty percent compared to the clean surface, which is in line with previous experiments. Adsorption on dimers enclosed by molecule (ethylene) covered surface atoms is reported to have a highly decreased reactivity, a result of destabilization of the intermediate state due to steric repulsion, as quantified with the periodic energy decomposition analysis (pEDA). Furthermore, an approach for the calculation of Gibbs energies of adsorption based on statistical thermodynamics considerations is applied to the system. The results show that the loss in molecular entropy leads to a significant destabilization of adsorption states.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
