Different coverages of fluorine adsorption on Mg (0 0 0 1) surface

The atomic fluorine adsorption in variety of sites on the Mg (0 0 0 1) surface has been systematically investigated through first-principles density functional theory (DFT) methods for coverages θ ⩽ 1.0 monolayer. It is found that the fcc-hollow site is the energetically most favorable for the whole coverage range considered. The adsorption energy decreases with the coverage θ. It can be also concluded from analysis of the charge density and density of states that the charges transfer from the substrate Mg atoms to the F atoms leads to the appearance of a dipole moment. With the increasing coverage, it becomes increasingly difficult to transfer electrons from Mg atoms to F atoms, resulting in the dipole moment to decline.