0000000000505439
AUTHOR
M. Perdereau
A static SIMS study of superficial reactions (O2, (CN)2) on silver
Abstract The exposure of silver surfaces to oxygen under about 10 −6 mbar at room temperature was studied mainly by secondary ion mass spectrometry (SIMS) used in a static mode. No reactivity of oxygen appeared under these exposure conditions in accordance with previous works. No modifications in the AES spectra, but an unexpected and huge increase in the intensities of secondary ions such as CN − , CNO − , Ag(CN) − 2 , Ag 2 CN + were observed. Different experiments were performed in order to specify the origin of this unexpected reaction in presence of pure oxygen. Moreover, exposures to pure (CN) 2 and to a mixture of cyanogen and oxygen were performed in order to compare the reactivity o…
Study by static SIMS, XPS and UPS of the adsorption of cyanogen on (100) Ni surfaces
Abstract The interaction of cyanogen with (100) Ni surfaces at room temperature was studied using secondary ion mass spectrometry in a static mode, and photoemission spectroscopies (XPS and UPS). It has been shown that cyanogen is adsorbed on this nickel surface in a dissociative mode: atomic carbon and nitrogen are present on the surface as well as CN fragments. These adsorbed species have been characterized by XPS and UPS. Increasing the temperature in the 400 K range increases the rate of the dissociation reaction of CN into atomic carbon and nitrogen. Moreover carbon is found to dissolved into the bulk for temperatures as low as 475 K. No evidence has been found of a polymerized form of…
A surface EXAFS study of thin nickel deposits on (110) TiO2 surfaces
Abstract The first stages of nickel deposition on a clean (110) TiO 2 surface were studied using surface extended X-ray absorption fine structure (EXAFS). Experiments were performed on two kinds of nickel deposits, one of 0.8 equivalent monolayers and another of 1.6 equivalent monolayers. Depositions were performed on well characterized TiO 2 (110)-p(1 × 1) surfaces. The correlation of Auger experiments with EXAFS results showed that no islands were present on the surface; only two-dimensional growth of nickel was observed. Moreover, it was shown, in the case of the thinner deposit, that a model with nickel atoms forming chains in the channels determined by oxygen atoms on the surface is co…