Initial oxidation of low index Mg surfaces investigated by SCLS and DFT

Magnesium (Mg) is a metal having a high structural efficiency and a very high chemical reactivity at the same time. Its potential areas of applications include the automotive industry, biomedicine, and energy storage and generation. Further developments in these very diverse application areas require a more detailed investigation of the behavior of Mg surfaces under oxidative conditions. The basic mechanisms of magnesium reactivity are not yet fully understood and therefore need to be further investigated by a combination of theoretical and experimental studies on representative surfaces with different crystallographic orientations. For this, we measured in situ high-resolution Mg 2p core level spectra at critical low-index Mg(0001), Mg(101¯0), and Mg(112¯0) surfaces to obtain surface core level shifts (SCLSs) at the early stages of Mg oxidation. We also used density functional theory (DFT) to obtain theoretical estimates of the SCLSs for respective surfaces and associated possible reconstructions to guide the analysis of the experimental spectra and to rule out un-reconstructed Mg(112¯0). DFT simulations were also used to reveal the energies of O atom adsorption, and the formation of evolving oxide structures in the Mg surfaces.