Microscopic theory of thermal desorption and dissociation processes catalyzed by a solid surface

A microscopic model of thermal desorption and dissociation from metallic surfaces which exhibits explicit dependences on characteristic parameters of the adsorption system is developed. The evaluation of the rates of these processes involves: (i) a derivation of the thermal adatom-solid coupling, (ii) a stochastic incoherent multiphonon mechanism for the evolution of an excitation for bond rupture, and (iii) coupling to final-state reaction channels. Transition probabilities and rates obtained by using both truncated-harmonic and Morse-potential descriptions of the chemisorptive bond are presented and compared with experimental data for xenon and potassium desorption from a tungsten substrate. The results show agreement with experiment and exhibit a linear relationship of the logarithm of the rate versus inverse temperature.