Adsorption of Thiophene on the RuS2(100) and (111) Surfaces: A Laplacian of the Electronic Charge Density Study

To study the effect of the surface Ru sulfur coordination number and of the surface S−H and Ru−H species into the thiophene adsorption on RuS 2, a topologic study of the Laplacian of the electronic density of selected (100) and (111) surfaces was carried out. It was found that a nonbonded local charge concentration on the S atom of the thiophene interacts with a local minimum on the outermost Ru atoms of the surfaces. This interaction is strongly affected by a nonbonded local charge concentration located on the outermost S atoms of the surface. Both interactions combine in such way that the strength of the thiophene adsorption on the unhydrogenated surfaces shows small changes. The main role of the S−H bond is to move away the surface sulfur local charge concentrations from the Ru atoms while the Ru−H species favors the hydride attacks to a local minimum located at the C α of the thiophene molecule.