Molecular beams and chemical dynamics at surfaces.

The use of molecular beams to study chemical dynamics at surfaces is outlined. The techniques is briefly introduced and its applications are given in a few areas. Scattering experiments give detailed information about the first steps toward a chemical reaction at a surface. Beams with enhanced population of specific quantum states make an even more detailed analysis possible. Adsorption at surfaces can be studied very well using beam methods, especially in the case of activated processes. Beams can be used to grow novel structures. Beams allow the study of chemical reactions at surfaces, and in particular those where product are directly ejected into the gas phase, or where reactions take place upon impact. Finally the study of liquid surfaces is briefly introduced.