ESTIMATION OF AD-VACANCY FORMATION ENERGY ON THE PT(111) SURFACE BY USING REFLECTION ELECTRON-MICROSCOPY

The quenching technique which is usually employed for studying lattice defects in metals was applied to estimate the formation energy of an ad-vacancy on the Pt(111) surface. These ad-vacancies coagulate in clusters, forming monoatomic step depression islands during cooling. They can be imaged by reflection electron microscopy as atomic step loops. The concentration of ad-vacancies at high temperatures could be measured from the total area of the atomic step loops covering the surface. The obtained value of ad-vacancy formation energy is about 0.62 eV on the assumption that the relation for the massive crystal can also be applied to the crystal surface phenomena.