Search

Abstract: Using a very weak electric field to accelerate the photofragment ions, we have constructed a very simple photofragment translational spectrometer with only a 50 mm total flight path, but we can get photofragment translational spectra with high resolution. On this apparatus, we have performed the photodissociation of CF3I at 281.73 nm, and the same laser will ionize I*(2P1/2) via REMPI. Seven well-resolved vibrational peaks were obtained. Six of them are assigned to the umbrella vibrational mode v2=0–5 states of photofragment CF3. The average internal energy is about 21% of the available energy. [Copyright &y& Elsevier]

The photodissociation of CF3I at 248 nm was performed on our high-resolution photofragment translational spectrometer. For further improvement of the resolution, we have taken the following procedures: (1) Kr was used as carrier gas, (2) optimum molecular beam angle θopt (when VMB⊥VCM) was selected, (3) the longitudinal molecular beam angle spread was reduced, and (4) the ionization region for photofragments was diminished. The photofragment translational spectra of I* (2P1/2) reveal eight well-resolved vibrational peaks. The highest peak was assigned to be v2=5 of the ν2 vibrational mode, and then the dissociation energy would be D0(C–I)=18 810±200cm−1=53.8±0.6 kcal/mol. [Copyright &y& Elsevier]