Vibrational and rotational population distribution of D2 associatively desorbing from Pd(100) -: art. no. 205412

The rotational and vibrational state distribution of D-2 molecules desorbing from Pd(100) is determined by tunable vacuum ultraviolet laser ionization spectroscopy. For the deuterium supply a permeation source is used operating at surface temperatures in the range from 400 to 850 K. The molecules are detected in rovibrational states up to (upsilon,J) = (0,12) and (1,8). A significant rotational cooling is observed together with a strong vibrational heating. These experimental results are found to be in good agreement with quantum-mechanical calculations based on an ab initio potential-energy surface. A consistent microscopic picture of the hydrogen reaction dynamics on Pd(100) is established and thus a recent controversy about the application of the principle of detailed balance in the system D-2/Pd(100) can be settled.