Troisi Alessandro, Beebe Jeremy M, Picraux Laura B, van Zee Roger D, Stewart Duncan R, Ratner Mark A, Kushmerick James G
Department of Chemistry and Centre for Scientific Computing, University of Warwick, Coventry CV4 7AL, United Kingdom.
Proc Natl Acad Sci U S A. 2007 Sep 4;104(36):14255-9. doi: 10.1073/pnas.0704208104. Epub 2007 Aug 28.
Using inelastic electron tunneling spectroscopy (IETS) to measure the vibronic structure of nonequilibrium molecular transport, aided by a quantitative interpretation scheme based on Green's function-density functional theory methods, we are able to characterize the actual pathways that the electrons traverse when moving through a molecule in a molecular transport junction. We show that the IETS observations directly index electron tunneling pathways along the given normal coordinates of the molecule. One can then interpret the maxima in the IETS spectrum in terms of the specific paths that the electrons follow as they traverse the molecular junction. Therefore, IETS measurements not only prove (by the appearance of molecular vibrational frequencies in the spectrum) that the tunneling charges, in fact, pass through the molecule, but also can be used to determine the transport pathways and how they change with the geometry and placement of molecules in junctions.
利用非弹性电子隧穿光谱（IETS）测量非平衡分子输运的振动电子结构，并借助基于格林函数 - 密度泛函理论方法的定量解释方案，我们能够表征电子在分子输运结中穿过分子时所经过的实际路径。我们表明，IETS观测结果直接索引了沿着分子给定法向坐标的电子隧穿路径。然后，可以根据电子穿过分子结时所遵循的特定路径来解释IETS光谱中的最大值。因此，IETS测量不仅（通过光谱中分子振动频率的出现）证明隧穿电荷实际上穿过了分子，而且还可用于确定输运路径以及它们如何随结中分子的几何形状和位置而变化。
