AVS 57th International Symposium & Exhibition
    Surface Science Tuesday Sessions
       Session SS-TuA

Paper SS-TuA7
STM Tip Induced Chemistry of Anthracene Derivatives on TiO2(110)

Tuesday, October 19, 2010, 4:00 pm, Room Picuris

Session: Chemical Dynamics at Surfaces
Presenter: D.V. Potapenko, Columbia University
Authors: D.V. Potapenko, Columbia University
R.M. Osgood, Columbia University
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Surface chemistry in photocatalysis is driven by the charge carriers that are created in the bulk of the catalyst and then are transferred to the adsorbed molecules. Both electrons and holes can be injected into molecules from the scanning tunneling microscope tip thus allowing mechanistic studies of photocatalytic processes on a single-molecule basis. We have studied adsorption and tip-induced surface chemistry of anthracene, as well as a number of anthracene derivatives on the TiO2(110) surface. These molecules form ordered monolayers on the surface at room temperature with their structure dictated by the surface-charge distribution on TiO2(110). Passing the electric current pulses from the STM tip into molecules causes dissociation and in some cases desorption of the molecules as indicated by the changes in the STM images. Halogenated organic molecules were especially susceptible to electron-induced dissociation with an energy threshold of ~ 2.5V. We report on the conditions of the tip-induced chemistry and propose a mechanism for the observed phenomena.