Matrix-Isolation Study of the Vacuum-Ultraviolet Photolysis of Methyl Fluoride. The Infrared Spectra of the Free Radicals CF, HCF, and H2CF

Abstract

Upon vacuum-ultraviolet photolysis of methyl fluoride in an argon or a nitrogen matrix at 14°K, the free radicals CF, HCF, and H2CF are stabilized in sufficient concentration for observation of their infrared absorption spectra. Studies utilizing carbon-13 and deuterium substitution confirm the identification of these species. Visible-ultraviolet absorption spectra of photolyzed Ar:CF3F samples include bands which may be assigned to CH, to CF, and to HCF. The reaction of carbon atoms, produced by the photolysis of cyanogen azide isolated in an argon matrix, with HF trapped in the matrix has also been found to lead to the stabilization of sufficient HCF for infrared spectroscopic detection. Reaction of HCF with a second molecule of HF to form CH2F2 also occurs. The force constants and thermodynamic properties of HCF have been calculated, and a partial vibrational assignment is proposed for H2CF. Although these experiments do not determine the primary photodecomposition processes important for methyl fluoride, there is evidence that both H atom and F atom detachment may occur under the conditions of these experiments.