ABSTRACT
This chapter describes chemical relaxation with a chemical change and physical relaxation with a structural change. The significant feature is the degree of the unsaturation of the chemical bond to which the internal structure terminates when the surface of the solid is looked at on the microscopic scale. Various surface relaxations appear for the stabilization because the solid surface has broken chemical bonds and exists in an unstable state. An atom, ion, or molecule on the surface receives an unsymmetrical interaction force, because chemical bonds have been cut on the crystal surface. For the chemical property of the oxide surface, one of the important characteristics for practical use might be the solid acid and base. The analysis method of a surface functional group is chiefly accomplished with a method based on a chemical reaction, spectroscopy methods such as infrared and nuclear magnetic resonance spectroscopy, and methods that combine both approaches.
