Structure of Cytosine on Cu(110): a Scanned-Energy Mode Photoelectron Diffraction Study
Structure of Cytosine on Cu(110): a Scanned-Energy Mode Photoelectron Diffraction Study
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DOI：
10.1021/jp105493f
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发表时间：
2010-09-16
影响因子：
3.7
通讯作者：
Woodruff, D. P.
中科院分区：
文献类型：
--
作者：
Jackson, D. C.;Duncan, D. A.;Woodruff, D. P.
用O 1 s和N1s扫描能量模式光电子衍射（PhD）研究了胞嘧啶在Cu（110）表面上的局域吸附结构.通过软X射线光电子能谱和O K边近边X射线吸收精细结构（NEXAFS）的初步表征表明，化学吸附导致分子环中NH物种的脱氢，并表明分子平面垂直于表面，接近[1（1）over bar 0]方位角。PhD结果证实了这种取向，并表明分子通过去质子化的N原子和O原子与表面键合，这两个原子都占据了非顶部位置。相关的Cu-N和Cu-O键长分别为1.94（+0.07/-0.03）和1.94（+0.06/-0.04）埃。密度泛函理论计算提供了进一步的支持，这种局部结构，并提供信息的分子间相互作用的可能作用。可能的结构模型占以前观察到的长程有序相滑移对称性进行了讨论，根据这些结果。
The local adsorption structure formed by the interaction of cytosine with a Cu(110) surface, following adsorption at similar to 300 K and annealing to similar to 420 K, has been investigated by O 1s and N 1s scanned-energy mode photoelectron diffraction (PhD). Initial characterization by soft-X-ray photoelectron spectroscopy and O K-edge near-edge X-ray absorption fine structure (NEXAFS) indicates that chemisorption leads to dehydrogenation of the NH species in the molecular ring and indicates that the molecular plane is perpendicular to the surface and close to the [1 (1) over bar0] azimuth. The PhD results confirm this orientation and show that the molecule bonds to the surface through the deprotonated N atom and the O atom, both of which occupy off-atop sites. The associated Cu-N and Cu-O bondlengths are 1.94(+0.07/-0.03) angstrom and 1.94(+0.06/-0.04) angstrom, respectively. Density functional theory calculations provide further support for this local structure and provide information on the possible role of intermolecular interaction. Possible structural models accounting for previously observed long-range ordered phases with glide symmetry are discussed in the light of these results.