Entropies of Desorption from Temperature Programmed Desorption Data:  Trends and Applications to Rate Constant Determinations

We show that entropies of desorption can be obtained from temperature programmed desorption (TPD) data. Corrected to the standard pressure of the thermodyanic reference state, these experimentally derived entropies are in general good agreement with Trouton's Rule for which there is theoretical evidence in the literature. Knowledge of these entropies allows the use of the large body of readily available gas-phase thermodynamic data in the determination of the rate constants for surface reactions and allows a more efficient determination of the Arrhenius preexponential factors for surface reactions.