Auger electron spectroscopy, ethylene

Thermal desorption of CO, Auger electron spectroscopy, and temperature programmed oxidation all show that the carbon layer 1) is Immobile below 550 K 2) forms a more densely packed surface phase at temperatures of 550-1150 K and 3) dissolves into the bulk at 1350 K. SIMS measurements of isotope mixing in the ions confirm formation of dense-phase (graphitic) islands after heating the carbon layer to 923 K. SIMS spectra also demonstrate that at 520 K, CO dissociates on Ru(OOl). The oxygen-free carbon layer that forms behaves similarly to the carbon from ethylene. Both SIMS and thermal desorption results show no positive interaction between adsorbed CO and D but significant attraction between and C formed by CO dissociation. 

Auger electron spectroscopy (AES) was used in combination with secondary ion mass spectrometry (SIMS) to distinguish between four types of carbonaceous deposits, on metal foils (rhodium, iridium and platinum). The foils were coked by exposing to ethylene at low pressure. Auger spectroscopy can distinguish between molecular or carbidic on the one hand, and graphitic or amorphous carbon on the other. The Auger spectrum of carbonaceous deposits on a metal is... 

Fig. 2. Experimental number of scattered electrons, N E), of energy, E, versus electron energy for a Rh(lll) surface covered with a monolayer of ethylidyne species (CCH3) -the stable, room temperature structure of chemisorbed ethylene. Boxes and inset figures show how particular scattered electrons are used in (a) Auger electron spectroscopy, (b) high resolution electron energy loss spectroscopy and (c) low energy electron diffraction...

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