Resolved (v1, v2 = 1) Combination Vibrational States of CF3 Fragments in the Photofragment Translational Spectra of CF3I.

Abstract

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 Eavl and higher ET, 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.