Angular distributions of desorbing N2 in thermal N2O decomposition on Rh(1 0 0)

The angular distribution of desorbing N₂ was studied in the decomposition of N₂O(a) on Rh(1 0 0) at 60-140 K by means of angle-resolved temperature-programmed desorption. N₂ desorption shows two peaks at around 80 K and 110 K. At low N₂O coverage, the former collimates far from the surface normal toward the 0 0 1] direction, whereas at high coverage, the desorption sharply collimates along the surface normal. The adsorption form of N₂O and its dissociation were also examined by DFT-GGA calculations. Dissociating N₂O is proposed to be lying along the 0 0 1] direction at low coverage and to change to an upright form bonding through the terminal oxygen at high coverage.