DECOMPOSITION OF NH3 ON RU(11(2)OVER-BAR1)

The thermal decomposition of NH3 was studied on the open Ru(11 (2) ove r bar 1) surface using high-resolution electron energy loss spectrosco py (HREELS) and thermal desorption spectroscopy (TDS), For small NH3 c overages up to 0.25 of a monolayer, NH3 decomposes completely during a nnealing of the sample. At higher coverages molecular desorption is al so observed. The dehydrogenation gives rise to sharp peaks in the H-2 TD spectra. NH2, NH, and N are identified using HREELS. A translationa l mode of NH3 is observed at 15 meV.