The infrared spectrum of trifluoronitromethane (CF3NO2) physically adsorbed on sublimated alkali halide (NaCl, NaBr, KCl, and KBr) films in submonolayer and multilayer coverages, and isolated in argon and nitrogen matrices, has been observed. The fundamental vibrations exhibit some surface-specific shifts, and there is indication that rotation about the CN bond is hindered upon adsorption. As in the gas phase, ultraviolet irradiation of the adsorbed species leads to the production of adsorbed carbonyl fluoride (CF2O), but an adsorbed FNO photoproduct was not observed, presumably lost to a secondary photolysis. Quantum efficiencies for photolysis were determined for submonolayer and multilayer species and were found to be independent of temperature (Phi = 0.20 +/- 0.20 adsorbed; 0.29 +/- 0.20 multilayer), reduced from that of the matrix-isolated species. These quantum efficiencies were used to determine rate constants for surface-induced relaxation of the adsorbate as a function of surface composition and temperature. Desorption isotherms for bath CF3NO2 and CF2O were observed and fit to a first-order kinetic model of desorption, with activation energies of desorption of 14 +/- 5 kJ mol(-1) for CF3NO2 on the sodium salts, 16 +/- 5 kJ mol(-1) for CF3NO2 on the potassium salts, and 28 +/- 6 kJ mol(-1) for CF3NO2 desorbing from overlayers.