THEORETICAL INVESTIGATIONS ON ADSORPTION AT ION CRYSTAL-SURFACES

Experimental and theoretical methods for the study of adsorption at io n crystal surfaces are reviewed. New SINDO1 calculations on surface-ad sorbate systems are presented in this framework. The special surface s ystems NaCl, MgO and TiO2 are selected to demonstrate the feasibility of current molecular orbital methods for the generation of surfaces an d the study of adsorption of small molecules exemplified by CO2 and H2 O. Molecular and dissociative adsorption can be distinguished in the c ase of adsorbed H2O. A scheme is presented for the systematic improvem ent of the results. Trends are discussed for geometry, binding charact eristics, energetics and infrared spectra of adsorbed molecules. The c alculated properties are compared with experimental data.