Adsorption and decompostion of NO and NH3 on Ru(001) and Ru(1,1,10) surfaces

Adsorption and decomposition of NO and NH3 on a Ru(001) flat surface and a Ru(1,1,10) stepped surface which possesses one step per five terrace widths have been investigated by means of XPS and UPS measurements. Adsorption of NO on the Ru(001) surface at 120 K exhibited two molecularly adsorbed NO states which were distinguished by O 1s core levels at 530.7 and 531.8 eV. On the Ru(1,1,10) surface the concentration of molecular NO states characterized by the O 1s level at 530.7 eV was quite smaller than that on the Ru(001) surface after saturated adsorption. The formation of surface nitrogen complexes, NHsub(x)(a) (x=0-3) could be characterized on the Ru(1,1,10) stepped surface by the successive shift of the N 1s core and valence level, whereas intermediate adsorbed species except for atomic nitrogen could not be detected on the Ru(001) flat surface. In the adsorption at 120 K molecular ammonia was adsorbed on both surfaces which exhibited a core emission at 400.0 eV and valence levels at 6.7 and 11.0 eV. Upon heating NH2(a) species was formed at 300 K which caused a shift of the N 1s core level to 398.1 eV and of the valence level to 7.4 eV, respectively. (orig./RK)