Selectivity in vibrationally mediated single-molecule chemistry
Selectivity in vibrationally mediated single-molecule chemistry
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DOI：
10.1038/nature01649
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发表时间：
2003-05
期刊：
影响因子：
64.8
通讯作者：
J. Pascual;N. Lorente;Zhen Song;H. Conrad;H. Rust
中科院分区：
文献类型：
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作者：
J. Pascual;N. Lorente;Zhen Song;H. Conrad;H. Rust
分子振动的选择性激发提供了直接影响化学反应的速度和结果的手段。这种模式选择化学传统上使用激光脉冲来制备特定振动状态的反应物，以增强反应性或改变产物物质的分布。非弹性隧穿电子也可以激发分子振动，并已被用于对吸附分子产生影响，以切断单个化学键并引起分子运动或解离。在这里，我们证明了非弹性隧穿电子可以被调谐，以选择性地诱导单个氨分子在Cu（100）表面上的平移或解吸。我们能够选择一个特定的反应途径，通过调整电子隧穿电流和能量在反应诱导过程中，使我们激活氨的伸缩振动或其金字塔结构的反转。我们的研究结果说明了扫描隧道显微镜探测单分子事件的能力在非常低的产量和非常低的功率照射的限制，这应该允许调查的反应途径不容易服从更传统的方法研究。
The selective excitation of molecular vibrations provides a means to directly influence the speed and outcome of chemical reactions. Such mode-selective chemistry has traditionally used laser pulses to prepare reactants in specific vibrational states to enhance reactivity,or modify the distribution of product species,. Inelastic tunnelling electrons may also excite molecular vibrations,and have been used to that effect on adsorbed molecules, to cleave individual chemical bonds and induce molecular motion,,,or dissociation,,,. Here we demonstrate that inelastic tunnelling electrons can be tuned to induce selectively either the translation or desorption of individual ammonia molecules on a Cu(100) surface. We are able to select a particular reaction pathway by adjusting the electronic tunnelling current and energy during the reaction induction such that we activate either the stretching vibration of ammonia or the inversion of its pyramidal structure. Our results illustrate the ability of the scanning tunnelling microscope to probe single-molecule events in the limit of very low yield and very low power irradiation, which should allow the investigation of reaction pathways not readily amenable to study by more conventional approaches.