Electron spin resonance study of the photolytic decomposition of CF3I in inert matrices between 4.2 degrees K and 35 degrees K

The electron spin resonance spectrum of the trifluoromethyl radical (CF3) produced by the photolytic decomposition of CF3I has been observed at 4.2 degrees K in xenon, krypton. and argon matrices. Complex spectra were observed in all cases and indicate that under these conditions the radical is randomly orientated and not free to rotate. At higher temperatures, similar to 35 degrees K, a basically four line spectrum is observed, but the two central lines are split, owing to second-order effects. into doublets with approximately 9 gauss separation. This somewhat simpler spectrum is attributed to the CF3 radical undergoing a rapid tumbling or isotropic motion. The isotropic g-values and isotropic part of the fluorine hyperfine coupling constant are g = 2.0032 +/- 0.0001 and a(F) = 140.5 +/- 0.1 gauss in xenon, and g = 2.0033 +/- 0.0001 and a(F) = 141.8 +/- 0.1 gauss in krypton.