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The photodissociation dynamics of ICl has been studied near 304 and 280 nm on a simple miniature time of flight (mini-TOF) photofragment translational spectrometer with a short pulse of a weak acceleration field. An intense hot band effect was observed. Many small peaks were resolved in each photofragment translational spectrum (PTS). Based on simulations, the principal peaks were assigned not only to the different photodissociation channels (1) I + Cl, (2) I + Cl*, (3) I* + Cl, or (4) I* + Cl*, but also to the different chlorine isotopes (Cl and Cl). Moreover, some extra peaks showed the existence of an intense hot band effect from vibrationally excited ICl molecules, though only a few percent of ICl molecules remained in the vibrationally excited states in our supersonic molecular beam. Based on the spectra near 304 nm, the quantum yield Φ of each channel, the curve crossing, and the branching fraction σ from each transition state were determined. [ABSTRACT FROM AUTHOR]

The photodissociation of ethyl iodide at 279.71, 281.73, 304.02 and 304.67 nm has been studied on our new mini-photofragment translational spectrometer with a total flight path of only 5 cm. Some vibrational peaks are firstly resolved in the TOF spectra of I*(2 P 1/2) and I(2 P 3/2) channels. These vibrational peaks are assigned to the excitation states ( v 2 = 0, 1, 2, ...) of the umbrella mode ( v 2, 540 cm−1) of the photofragment C2H5, and the distribution of the vibrational states is obtained. The dissociation energy has been determined to be D 0(C-I)=2.314 ± 0.03 eV. The energy partitioning of the available energy ( E avl= E T+ E int= E T+ E V,R) calculated from our experimental data Ē int / E avl = 22.1% at 281.73 nm, 22.4% at 304.02 nm for the I* channel, and Ē int / E avl = 25.2% at 279.71 nm, 25.9% at 304.67 nm for the I channel, seem to be more reliable. [ABSTRACT FROM AUTHOR]