0000000000994033
AUTHOR
T. Brudevoll
First-Principles Simulations of Interstitial Atoms in Ionic Solids
The atomic and electronic structure of the radiation-induced interstitial atoms in MgO and KCl crystals representing two broad classes of ionic solids are calculated and compared. The first-principles full potential LMTO method is applied to a 16-atom supercell. For both crystals the energetically most favourable configuration is a dumbbell centered at a regular anion site. Its (110) and (111) orientations are very close in energy which permits the dumbbell to rotate easily on a lattice site. The mechanism and the relevant activation energy for thermally activated diffusion hops from the dumbbell equilibrium position to the cube face and cube center are discussed in the light of the availab…
Interstitial-oxygen-atom diffusion in MgO.
configuration is the ~111! dumbbell centered at a regular oxygen site, whereas face-centered and cube-centered configurations are higher in energy by 1.45 eV and 3.57 eV, respectively. The~111! configuration isclose in energy to the ~110! configuration, which allows the dumbbell to rotate easily on a lattice site. In allthese four cases the interstitial oxygen atom attracts considerable additional electron density from its nearestregular O