DFT plane-wave calculations of the Rh/MgO(0 0 1) interface

The Rh/MgO(0 0 1) system has been studied by periodic plane-wave density functional calculations using the VASP code and PAW potentials. Four different adsorption sites (which were reduced to three after optimization) and three different surface coverages were investigated. For the most stable site, above O, the adhesion energy was found to decrease as a function of coverage (from 2.0 to 1.1 eV as the coverage increases from 1/8 to 1 ML), while the adsorption energy was found to increase with surface coverage. Electron density difference plots were calculated to display some of the electron rearrangement responsible for the Rh–oxide adhesion energy, and the features of the Mg and O adsorption sites were compared.