Structural paradox in submonolayer chlorine coverage on Au(111)

In this work, we present a combined low-temperature scanning tunneling microscopy (STM) and density functional theory (DFT) study of chlorine adsorption on Au(111) at low coverages. Our STM study of Cl/Au(111) system has shown that at submonolayer coverages ($\ensuremath{\theta}<$ 0.1 ML) chlorine atoms form chainlike structures with abnormally short distances of 3.8 \AA{} between them. Our DFT calculations have shown that chlorine atoms can interact with each other through distortion of the substrate and this indirect elastic interaction is strong enough to affect their arrangement in the chainlike structures.