The adsorption and reaction of acetaldehyde on the clean and CO pre-covered Ru（0001） surfaces have been investigated using temperature programmed desorption method. On the clean Ru（0001） surface, the decomposition of acetaldehyde is the main reaction channel, with little polymerization occurring. However, on the CO pre-covered Ru（0001） surface, the de- composition of acetaldehyde is inhibited considerably with increasing CO coverage. Whereas, the polymerization occurs efficiently, especially at high CO coverage （θco〉0.5 ML）, which is strongly CO coverage dependent. Combined with previous studies, the well-ordered hexagohal structure of CO layer formed on the Ru（0001） surface at high CO coverage that matches the configuration of paraldehyde is likely to be the origin of this remarkable phenomenon.
Photodissociation of jet-cooled HOD via the C state around 124 nm has been studied using the H（D）-atom Rydberg tagging time-of-flight technique. Rotational state resolved action spectrum and the product translational energy distribution spectra have been recorded for both D＋OH and H＋OD dissociation channels. Product channel OH/OD branching ratios for the individual C-X rotational transition have been determined. A comparison is also given with the B-X and A-X transitions. In addition, the dissociation energy of the OD bond in HOD has been determined accurately to be 41751.3±5 cm-1.
