REACTION OF TRIFLUOROMETHYL IODIDE ON NI(100)

We have studied the surface chemistry of trifluoromethyl iodide adsorb ed on Ni(100) under ultrahigh-vacuum conditions. Temperature-programme d desorption and reflection absorption infrared spectroscopy were used to determine gas-phase products and species formed at the surface. Se veral reaction products were found from trifluoromethyl iodide dissoci ation on Ni(100). Iodine atoms and nickel fluoride, NiF2, desorb at hi gh temperatures near 1000 and 800 K, respectively. At high coverages, carbon-containing species desorb from the surface as well. CF3I and CF 3 desorb at 168/136 K (mono/multilayer) and 316 K, respectively. In th e presence of background hydrogen, HF and CH2F2 are also detected in t emperature-programmed desorption at 178 and 235 K, respectively. The i nfrared spectra of multilayer, monolayer, and submonolayer coverages o f CF3I on the surface and adsorbed CFx groups have been measured. The temperature-programmed desorption and infrared data show that both car bon-iodine and carbon-fluorine bonds are readily activated on nickel a t low temperatures. It is estimated that approximately 90% of adsorbed CF3I decomposes on Ni(100).