CF3I ADSORPTION ON NI(100)

The adsorption of CF3I on Ni{100} has been studied using LEED and AES. At 323 K CF3I adsorbed dissociatively to form a p(2×2) consisting of 1/8 ML of iodine atoms, and 1/8 ML of CF3. Heating this surface to temperatures greater than 470 K caused CF3 to desorb from the surface; the desorption was complete by 770 K. Adsorption at elevated temperatures occurred with an initial rate of adsorption three times that for 323 K adsorption, as measured by iodine uptake; CF3 desorption occurred during the adsorption process, leaving a surface of pure chemisorbed iodine of between 1/3 ML and 5/12 ML coverage, depending on the temperature used.