A review of experimental data on the desorption of excited molecules that are the products of heterogeneous catalytic reactions is given. It is shown that the sharply peaked spatial distributions of desorption flows (SDDFs) are observed in many systems. The translational energies of the products (T_(tr)) are much higher than the surface temperatures. A correlation of SDDF parameters and T_(tr) is found. The excitation of internal degrees of freedom (vibrations and rotations) is weaker. The vibrational and rotational temperatures (T_(vib) and T_(rot)) obey the following inequalities: T_(tr) > T_(vib) > T_(rot) or T_(tr) ≥ T_(vib) > T_(rot), and T_(rot) ≈ T_(surf). Models for the description of the desorption of excited molecules are considered. New data on the active sites for anisotropic and stepped surfaces, from which desorption occurs, are discussed.
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