Controlling organic reactions on silicon surfaces with a scanning tunneling microscope: theoretical and experimental studies of resonance-mediated desorption.
The dynamics of tip-induced, resonance-mediated bond-breaking in complex organic adsorbates is studied theoretically and experimentally. Desorption of benzene from a Si(100) surface is found to be efficient and sensitive to voltage, the measured yield rising from below 10(-10) to ca. 10(-6) per electron within a ca. 0.8 V range at low (< 100 pA) current. A theoretical model, based upon first principles electronic structure calculations and quantum mechanical wavepacket simulations, traces these observations to multi-mode dynamics triggered by a transition into a cationic resonance. The model is generalized to provide understanding of, and suggest a means of control over, the behaviour of different classes of organic adsorbates under tunneling current.
Steacie Institute for Molecular Sciences, National Research Council of Canada, Ottawa, Ontario, K1A 0R6, Canada.
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Alavi
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Rousseau
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Lopinski
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Wolkow
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Seideman