REACTION OF TRIFLUOROMETHYL IODIDE ON NI(100)

We have studied the surface chemistry of trifluoromethyl iodide adsorbed on Ni(100) under ultrahigh-vacuum conditions. Temperature-programmed desorption and reflection absorption infrared spectroscopy were used to determine gas-phase products and species formed at the surface. Several reaction products were found from trifluoromethyl iodide dissociation on Ni(100). Iodine atoms and nickel fluoride, NiF2, desorb at high temperatures near 1000 and 800 K, respectively. At high coverages, carbon-containing species desorb from the surface as well. CF3I and CF3 desorb at 168/136 K (mono/multilayer) and 316 K, respectively. In the presence of background hydrogen, HF and CH2F2 are also detected in temperature-programmed desorption at 178 and 235 K, respectively. The infrared spectra of multilayer, monolayer, and submonolayer coverages of CF3I on the surface and adsorbed CFx groups have been measured. The temperature-programmed desorption and infrared data show that both carbon-iodine and carbon-fluorine bonds are readily activated on nickel at low temperatures. It is estimated that approximately 90% of adsorbed CF3I decomposes on Ni(100).