Simulation of thermal desorption spectra of N2 observed during N2O decomposition on Rh(1Â 1Â 0)

Under temperature-programmed conditions, N2O decomposition occurs on Rh(1 1 0) between 60 and 190 K and results in N2 desorption. Experimental studies of the angular distribution of the flux of the reaction products indicate that N2 molecules leave the surface both during and after N2O dissociation events. The N2 TPD spectra observed are complex. In particular, there are four peaks, registered between 60 and 150 K and related to N2 desorption accompanying N2O-dissociation acts, and a peak recorded at 160 K and attributed to desorption of adsorbed N2 molecules. We present Monte Carlo simulations of these spectra. Our model takes into account both channels of N2 desorption and also N2O-O lateral interactions stabilizing N2O adsorption. With these relatively simple ingredients, the model reproduces the main features of the measured TPD kinetics, including the positions and intensities of all the peaks.