Density fluctuations as door-opener for diffusion on crowded surfaces

Abstract

A path through a crowd Catalytic reactions on surfaces occur at pressures at which the surfaces are completely covered with adsorbed molecules. It would seem that this arrangement would interfere with reactants encountering one another through diffusion processes. Henß et al. used high-speed scanning tunneling microscopy to follow the diffusion of oxygen atoms on a ruthenium surface that was fully covered with carbon monoxide (CO) molecules (see the Perspective by Magnussen). Oxygen-atom diffusion was unexpectedly fast. A theoretical model revealed that CO diffusion appears to open pathways for oxygen-atom movement. Science , this issue p. 715 ; see also p. 695