Structure determination of propyne and 3,3,3-trifluoropropyne on Cu(111)
Structure determination of propyne and 3,3,3-trifluoropropyne on Cu(111)
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Cu(111)上丙炔和3,3,3-三氟丙炔的结构测定
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
R. M. Lambert
中科院分区：
文献类型：
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作者：
R. L. Toomes;R. Lindsay;P. Baumgärtel;R. Terborg;J. Hoeft;A. Koebbel;O. Schaff;M. Polcík;James C. Robinson;D. P. Woodruff;A. Bradshaw;R. M. Lambert
用扫描能光电子衍射技术获得了丙炔(CH3CCH)和3，3，3-三氟丙炔(CF3CCH)在铜(111)表面的吸附位置和内部结构的详细信息。这两个分子都通过乙炔单元结合到表面，其位置类似于以前在铜(111)上发现的乙炔的位置。具体地说，乙炔单元在交叉桥位置上平行于表面，使得一个C原子在fcc中空位之上，而另一个在hcp中空位之上，从而使C-C键长度为1.47A。甲基/三氟甲基强烈地倾斜离开表面，并且以相同的概率与fcc和hcp中空位中的C原子结合。分子平面垂直于表面。CF3CCH的氟基在顺式构象中优先取向。根据LEED谱图和计算的0.25ML覆盖范围，推测了丙炔和3，3，3-三氟丙炔在Cu(111)面上的可能覆盖排列。
The technique of scanned-energy photoelectron diffraction has been used to obtain detailed information on the adsorption site and internal structure of propyne (CH3CCH) and 3,3,3-trifluoropropyne (CF3CCH) on Cu(111). Both molecules are bound to the surface via the acetylenic unit in a site analogous to that previously found for ethyne on Cu(111). In particular, the acetylenic unit is parallel to the surface in a cross-bridging position such that one of the C atoms is above a fcc hollow site while the other is above a hcp hollow site, giving a C–C bond length of 1.47 A. The methyl/trifluoromethyl group is strongly tilted away from the surface and is attached with equal probability to the C atoms in the fcc and hcp hollow sites. The molecular plane is perpendicular to the surface. The fluoro group of CF3CCH is preferentially oriented in the cis conformation. From the LEED pattern and the calculated coverage of 0.25 ML, a possible overlayer arrangement for propyne and 3,3,3-trifluoropropyne on Cu(111) has be...