Jumping, Rotating, and Flapping: The Atomic-Scale Motion of Thiophene on Cu(111)
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- 作者：Barbara A. J. Lechner ; Marco Sacchi ; Andrew P. Jardine ; Holly Hedgeland ; William Allison ; John Ellis ; Stephen J. Jenkins ; Paul C. Dastoor ; B. J. Hinch
- 刊名：The Journal of Physical Chemistry Letters
- 出版年：2013
- 出版时间：June 6, 2013
- 年：2013
- 卷：4
- 期：11
- 页码：1953-1958
- 全文大小：298K
- 年卷期：v.4,no.11(June 6, 2013)
- ISSN：1948-7185
文摘
Self-assembled monolayers of sulfur-containing heterocycles and linear oligomers containing thiophene groups have been widely employed in organic electronic applications. Here, we investigate the dynamics of isolated thiophene molecules on Cu(111) by combining helium spin-echo (HeSE) spectroscopy with density functional theory calculations. We show that the thiophene/Cu(111) system displays a rich array of aperiodic dynamical phenomena that include jump diffusion between adjacent atop sites over a 59鈥?2 meV barrier and activated rotation around a sulfur鈥揷opper anchor, two processes that have been observed previously for related systems. In addition, we present experimental evidence for a new, weakly activated process, the flapping of the molecular ring. Repulsive inter-adsorbate interactions and an exceptionally high friction coefficient of 5 卤 2 ps鈥? are also observed. These experiments demonstrate the versatility of the HeSE technique, and the quantitative information extracted in a detailed analysis provides an ideal benchmark for state-of-the-art theoretical techniques including nonlocal adsorbate鈥搒ubstrate interactions.