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arXiv 0811.3088cond-mat.mtrl-sci
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胸腺嘧啶在Cu(110)表面的第一性原理和半经验范德华研究

First-principles and semi-empirical van der Waals study of thymine on Cu(110) surface

V. Caciuc, N. Atodiresei, P. Lazic, Y. Morikawa, S. Blugel

摘要:

本文采用密度泛函理论计算方法研究了胸腺嘧啶(C $_5$ H $_6$ N $_2$ O $_2$)分子在Cu(110)表面的吸附几何构型和成键机理.在最稳定的能量配置中,分子平面沿着$[1\bar{1}0]$方向垂直于衬底取向。对于这种吸附几何形状,胸腺嘧啶分子通过一个去质子化的氮原子和两个氧原子与表面相互作用,使得键合机制涉及最高占据分子轨道(HOMO)和基底的d-态之间的强杂交。在平行吸附几何形状的情况下,长程范德华相互作用对分子表面几何形状和吸附能都起着重要作用。通过半实证和无缝对接的方法分析了它们的具体作用。特别是,对于一个平面的配置,包括分散效果显着改变的字符的吸附过程从物理吸附到化学吸附。最后,我们通过模拟扫描隧道显微镜(STM)图像预测了分子-表面界面的真实空间形貌。从这些模拟,我们预计,只有某些吸附几何形状可以在STM实验中成像。

英文摘要:

In this study we investigated by means of density functional theory calculations the adsorption geometry and bonding mechanism of a single thymine (C$_5$H$_6$N$_2$O$_2$) molecule on Cu(110) surface. In the most stable energetic configuration, the molecular plane is oriented perpendicular to substrate along the $[1\bar{1}0]$ direction. For this adsorption geometry, the thymine molecule interacts with the surface via a deprotonated nitrogen atom and two oxygen ones such that the bonding mechanism involves a strong hybridization between the highest occupied molecular orbitals (HOMOs) and the d-states of the substrate. In the case of a parallel adsorption geometry, the long-range van der Waals interactions play an important role on both the molecule-surface geometry and adsorption energy. Their specific role was analyzed by means of a semi-empirical and the seamless methods. In particular, for a planar configuration, the inclusion of the dispersion effects dramatically changes the character of the adsorption process from physisorption to chemisorption. Finally, we predict the real-space topography of the molecule-surface interface by simulating scanning tunneling microscopy (STM) images. From these simulations we anticipate that only certain adsorption geometries can be imaged in STM experiments.

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。

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