Chlorine adsorption on Mg, Ca, and MgCa surfaces

The surface energies and work functions of Mg, Ca, and MgCa surfaces are derived by means of first principles calculation, and it is found that the Ca-terminated B2 MgCa surfaces have much lower surface energies than corresponding Mg-terminated surfaces. Moreover, calculations reveal that the adsorption energy of Cl atom on Ca (111) surface is much lower than that on Mg (0001) surface due to a stronger CaCl bond than MgCl, and that for MgCa (110) surface, various possible adsorption of Cl atoms are investigated and the most energetically preferred site is found. In addition, the magnitude of adsorption energies suggest that the corrosion resistance of MgCa (110) surface against Cl atom would be located between those of Mg (0001) and Ca (111) surfaces. The relative stability of various adsorption sites is discussed by means of electronic structures, and the present calculated results are in good agreement with experimental results in the literature.