Resolved (v₁, v₂ = 1) Combination Vibrational States of CF₃ Fragments in the Photofragment Translational Spectra of...

The photodissociation of CF₃I → CF₃(v₁,v₂) + I*/I has been investigated at 248, 266, and 277 nm with our high resolution mini-TOF photofragment translational spectrometer. Based on the theoretical calculations of Clary and of Bowman et al., now in this manuscript, we assign 701 cm^-1 to the CF symmetric stretch (breathing) ν₁ mode, and 1086 cm^-1 to the umbrella ν₂ mode of the CF₃ fragment. In the obtained TOF spectra of I⁺ from the I* channel, situated in the 701 cm^-1 gaps between the original series of (v₁, 0) vibrational peaks, a new series of weaker (v₁, 1) vibrational peaks are partially resolved. These observed new peaks with 1086 cm^-1 ν₂ mode excitation have never been reported in previous literature. In the TOF spectra of I⁺ from the I channel, the new series of (v₁, 1) peaks are also partially resolved. However, these spectra of I channel are less satisfactory, because for higher E_avl and higher E_T, the higher resolution of PTS is required. The potential energy at the curve crossing point and the excitation of CF₃ (v₁, 2) and (v₁, 3) vibrational states have been also analyzed.