The surface-induced and electron-induced chemistry of trifluoroiodomethane (CF3I), a potential replacement for chlorofluorocarbons (CFCs) and chlorofluorobromocarbons (halons), were investigated under ultrahigh vacuum conditions (p ∼ 1 × 10-10 Torr) on Mo(110). Results of temperature-programmed desorption (TPD) experiments indicate that dissociative adsorption of CF3I leads only to nonselective decomposition on Mo(110), in contrast to reactions of CF3I on other metal surfaces. Desorption of CF3 radicals and atomic iodine was detected mass spectrometrically during low-energy (10−100 eV) electron irradiation of four monolayer thick films of CF3I condensed at 100 K. Results of postirradiation temperature-programmed desorption experiments were used to identify CF2I2, C2F5I, C2F6, C2F4I2, and CFI3 as electron-induced reaction products of CF3I. Except for CFI3, all of these electron-induced reaction products of CF3I have been previously identified in γ-radiolysis studies, supporting our earlier claim that temperature-programmed desorption experiments conducted following low-energy electron irradiation of multilayer thin films provide an effective method to investigate the effects of high-energy radiation, including radical−radical reactions.

Recent advances in spot-welding technology such as high frequency direct current inverter welders provide an improved and reproducible method to spot-weld difficult junctions. The importance of removing the oxide layers on metal surfaces, accurately delivering the weld pulse profile, and controlling the force applied to the materials during the welding process are discussed in the context of resistance spot-welding a molybdenum crystal to a tantalum loop and attaching a tungstenrhenium thermocouple to the crystal.