title: Vibrationally resolved photofragment translational spectroscopy of CH3I from 277 to 304 nm with increasing effect of the hot band.
abstract: The photodissociation dynamics of CH(3)I from 277 to 304 nm is studied with our mini-TOF photofragment translational spectrometer. A single laser beam is used for both photodissociation of CH(3)I and REMPI detection of iodine. Many resolved peaks in each photofragment translational spectrum reveal the vibrational states of the CH(3) fragment. There are some extra peaks showing the existence of the hot-band states of CH(3)I. After careful simulation with consideration of the hot-band effect, the distribution of vibrational states of the CH(3) fragment is determined. The fraction σ of photofragments produced from the hot-band CH(3)I varies from 0.07 at 277.38 nm to 0.40 at 304.02 nm in the I* channel and from 0.05 at 277.87 nm to 0.16 at 304.67 nm in the I channel . E(int)/E(avl) of photofragments from ground-state CH(3)I remains at about 0.03 in the I* channel for all four wavelengths, but E(int)/E(avl) decreases from 0.09 at 277.87 nm to 0.06 at 304.67 nm in the I channel . From the ground-state CH(3)I, the quantum yield Φ(I*) is determined to be 0.59 at 277 nm and 0.05 at 304 nm. The curve-crossing probability P(cc) from the hot-band CH(3)I is lower than that from the ground-state CH(3)I. The potential energy at the curve-crossing point is determined to be 32,740 cm(-1).
authors.affiliation: Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.
authors.forename: Min
authors.initials: M
authors.lastname: Cheng
authors.forename: Zijun
authors.initials: Z
authors.lastname: Yu
authors.forename: Lili
authors.initials: L
authors.lastname: Hu
authors.forename: Dan
authors.initials: D
authors.lastname: Yu
authors.forename: Changwu
authors.initials: C
authors.lastname: Dong
authors.forename: Yikui
authors.initials: Y
authors.lastname: Du
authors.forename: Qihe
authors.initials: Q
authors.lastname: Zhu