Emission spectra of CF3 radicals. III. Spectra and quenching of CF3 emission bands produced in the VUV photolyses of CF3Cl and CF3Br

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Abstract
Fluorescence in the photolysis of CF3Cl and CF3Br was investigated using various vacuum ultraviolet light sources of atomic lines (Ar, Kr, H, and O). Both UV and visible emission bands of CF3 were observed as in the case of the photolysis of CF3H. Lower v′ levels of the emission bands were excited when CF3X was photolyzed by the lower energy incident light. In the case of CF3Cl, the emission bands were observed by the hydrogen Lyman alpha line, but no emission was observed by the krypton lamp with a CaF2 window. The threshold energy required to produce the UV and visible emission bands should be in the region 10.03–10.20 eV for CF3Cl. The energy separation between the fluorescing upper state and the ground state of CF3 is smaller than 6.52 eV. The emission bands were quenched by the addition of N2. Vibrational relaxation was predominant in the emission bands when He was added. Total intensity of the UV emission bands decreased and that of the visible emission bands increased by the addition of He. The results show that the UV and visible emission bands of CF3 would not originate from the same electronically excited state. Collision induced cross transfer from the state associated with the UV emission to that associated with the visible emission was observed.