Experimental observation of quantum oscillation of surface chemical reactivities.

Ma, Xucun; Jiang, Peng; Qi, Yun; Jia, Jinfeng; Yang, Yu; Duan, Wenhui; Li, Wei-Xue; Bao, Xinhe et al. · Proc Natl Acad Sci U S A · 2007

basic_science · Level V

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Abstract

Here we present direct observation of a quantum reactivity with respect to the amounts of O(2) adsorbed and the rates of surface oxidation as a function of film thickness on ultrathin (2-6 nm) Pb mesas by scanning tunneling microscopy. Simultaneous spectroscopic measurements on the electronic structures reveal a quantum oscillation that originates from quantum well states of the mesas, as a generalization of the Fabry-Pérot modes of confined electron waves. We expect the quantum reactivity to be a general phenomenon for most ultrathin metal films with broad implications, such as nanostructure tuning of surface reactivities and rational design of heterogeneous catalysts.