Dehydrogenation of Aromatic Molecules under a Scanning Tunneling Microscope: Pathways and Inelastic Spectroscopy Simulations

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• 作者：Hervé ; Lesnard ; Marie-Laure Bocquet ; Nicol&aacute ; s Lorente
• 刊名：Journal of the American Chemical Society
• 出版年：2007
• 出版时间：April 11, 2007
• 年：2007
• 卷：129
• 期：14
• 页码：4298 - 4305
• 全文大小：392K
• 年卷期：v.129,no.14(April 11, 2007)
• ISSN：1520-5126

文摘

We have performed a theoretical study on the dehydrogenation of benzene and pyridine moleculeson Cu(100) induced by a scanning tunneling microscope (STM). Density functional theory calculationshave been used to characterize benzene, pyridine, and different dehydrogenation products. The adiabaticpathways for single and double dehydrogenation have been evaluated with the nudge elastic band method.After identification of the transition states, the analysis of the electronic structure along the reaction pathwayyields interesting information on the electronic process that leads to H-scission. The adiabatic barriersshow that the formation of double dehydrogenated fragments is difficult and probably beyond reach underthe actual experimental conditions. However, nonadiabatic processes cannot be ruled out. Hence, in orderto identify the final dehydrogenation products, the inelastic spectra are simulated and compared with theexperimental ones. We can then assign phenyl (C₆H₅) and s/gifchars/alpha.gif" BORDER=0>-pyridil (s/gifchars/alpha.gif" BORDER=0>-C₅H₄N) as the STM-induceddehydrogenation products of benzene and pyridine, respectively. Our simulations permit us to understandwhy phenyl, pyridine, and s/gifchars/alpha.gif" BORDER=0>-pyridil present tunneling-active C-H stretch modes in opposition to benzene.