Mapping the site-specific potential energy landscape for chemisorbed and physisorbed aromatic molecules on the Si(1 1 1)-7 × 7 surface by time-lapse STM

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  • University of Bath


We present a scanning tunnelling microscope study of site-specific thermal displacement (desorption or diffusion) of benzene, toluene, and chlorobenzene molecules on the Si(1 1 1)-7 × 7 surface. Through time-lapse STM imaging and automated image analysis we probe both the chemisorbed and the physisorbed states of these molecules. For the chemisorption to physisorption transition there are distinct site-specific variations in the measured rates, however their kinetic origin is ambiguous. There is also significant variation in the competing rates out of the physisorbed state into chemisorption at the various surface sites, which we attribute to differences in site-specific Arrhenius pre-factors. A prediction of the outcome of the competing rates and pre-factors for benzene over three hours matches experiment.


Original languageEnglish
Article number054003
JournalJournal of Physics: Condensed Matter
Early online date21 Nov 2014
Publication statusPublished - Feb 2015