Application of transition state theory to desorption from solid surfaces: Ammonia on Ni(111)

We have used transition state theory to derive analytical expressions for the rates of desorption of atoms and molecules (diatomic as well as polyatomic) from solid surfaces. Realistic forms for the three dimensional adsorbate-surface interaction potentials are employed, including surface corrugation. Using potential parameters from a combination of experiment and ab initio calculations we have applied the rate expressions to evaluate the temperature programmed desorption spectra of NH₃ from Ni(111). Comparing these curves to the experimental spectra leads to a bond energy of D₀ = 21.0-3.7 Θ kcal/mol, where Θ is the fraction of saturation coverage.