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arXiv · 1008.2414

Two-photon Induced Hot Electron Transfer to a Single Molecule in a Scanning Tunneling Microscope

Shiwei Wu·Wilson Ho
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Abstract

The junction of a scanning tunneling microscope (STM) operating in the tunneling regime was irradiated with femtosecond laser pulses. A photo-excited hot electron in the STM tip resonantly tunnels into an excited state of a single molecule on the surface, converting it from the neutral to the anion. The electron transfer rate depends quadratically on the incident laser power, suggesting a two-photon excitation process. This nonlinear optical process is further confirmed by the polarization measurement. Spatial dependence of the electron transfer rate exhibits atomic-scale variations. A two-pulse correlation experiment reveals the ultrafast dynamic nature of photo-induced charging process in the STM junction. Results from these experiments are important for understanding photo-induced interfacial charge transfer in many nanoscale inorganic-organic structures.

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Shiwei Wu, Wilson Ho. 2010-08-14. Two-photon Induced Hot Electron Transfer to a Single Molecule in a Scanning Tunneling Microscope. https://doi.org/10.1103/physrevb.82.085444

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