Abstract
The interaction of Rb, Pd, and Ag atoms with the surface vacancies of MgO, the Fs and the Vs centers, has been studied by ab initio cluster model wave functions. We have considered the interaction of each atom with Fs, Fs+, Fs2+, Vs, Vs-, and Vs2- sites. These sites correspond to the removal of O, O-, O2-, Mg, Mg+, and Mg2+ atoms or ions, respectively, from the surface. The bond with the metal atoms, which is found to be very weak on the regular surface sites, can be very different depending of the formal charge of the vacancy. Neutral Fs centers are in general rather unreactive as their electronic structure resembles that of the regular surface; Fs+ paramagnetic centers have a relatively large electron affinity and tend to ionize metal atoms with low ionization potentials, such as alkali-metal atoms or to form covalent polar bonds with the adsorbed metal atoms; Fs2+ centers have a very high electron affinity so that all metal atoms are ionized when interacting with these sites. Neutral Vs sites are also ...
Published Version
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