SPATIAL-DISTRIBUTION OF N-2, O-2 AND NO MOLECULES DESORBING FROM A [P(2X1)-O-N]AG(110) SURFACE(P(2X3))

Temperature-programmed desorption of a [p(2 X 3)-N + p(2 X I)-O]Ag(110 ) surface gives simultaneous desorption of N-2 and NO at 520 K and the desorption of O-2 at 600 K. The STM image showed a competitive array of (Ag4N) rows and (-Ag-O-) strings. N2 is formed by self-recombinatio n of N-atoms, and NO is formed by the reaction of N-atoms with (-Ag-O- ) strings. The spatial distribution of NO (520 K) took two maxima, in the normal and ca. 17 degrees off-normal directions, although N-2 and O-2 desorb only in the normal direction. These two maxima may reflect the reaction of N-atoms with O-atoms at the terminal and inside of the (-Ag-O-) strings. (C) 1998 Elsevier Science B.V. All rights reserved.