A SCAN+rVV10 study of Thiophene adsorption on Ir, Rh, and Ag (100)

Using density functional theory we study the adsorption of thiophene on Ir, Rh, and Ag(100) surfaces. Specifically, we employ the meta-GGA SCAN+rVV10 functional. To assess the performance of SCAN+rVV10 we compared our SCAN+rVV10 results to results calculated using the popular van der Waals (vdW) inclusive GGA functional, optB88-vdW. To find the equilibrium adsorption geometry, we explore a variety of adsorption sites with the plane of the molecule both parallel and perpendicular to the surface. Along with the equilbirum adsorption geometry we present various geometric and electronic properties of the adsorbate/substrate systems such as adsorption energy, adsorption height, buckling of the first layer of the substrate, charge transfer to the molecule, change in the width and center of the surface’s d-band, and change in the surface’s work funcntion. We find over all surfaces both functionals predict thiophene to adsorb parallel to the surface. Besides the consensus on a flat adsorption site, generally we find SCAN+rVV10 and optB88-vdW to agree very well concerning thiophene adsorption over Ag(100) and moderately well concerning thiophene adsorption over Rh(100) and Ir(100).