Adsorption of metadiiodobenzene on Cu(110): a theoretical study

In this work, we have computationally modeled the adsorption of 1,3-diiodobenzene (meta-diiodobenzene or m-DIB) on Cu(1 1 0) by means of density functional theory including van der Waals interaction using Grimme's method. We have compared the adsorption energies and structures of 23 possible configurations of the physisorbed molecule. Furthermore, we have simulated STM images for the four most stable configurations using the Tersoff-Hamann approach at different bias voltages. We find that all the adsorption orientations have comparable energy, and we discuss the relative probabilities of experimental observation. We find that the adsorption induces small distortions in the molecular structure of the adsorbate and in some cases an adsorption-induced symmetry breakdown occurs. We also find evidence that the most stable arrangement is actually a bistable system with interesting symmetry properties.