Photodissociation of CD_3SCD_3 on the First Absorption Band: Translational and Internal Energy Transfer to the CD_3 Fragment Studied by Resonant Multiphoton Ionization and Time-of-Flight Spectrometry

摘要

The photodissociation of deuterated dimethyl sulfide (CD_3SCD_3) has been studied in the first absorption band at a laser wavelength of 229 nm. The resonance-enhanced multiphoton ionization time-of-flight technique has been employed to determine the recoil energy distribution and the anisotropy parameter β and to study the rovibrational state population of the nascent CD_3. The observed value β = -0.9 ± 0.1 (perpendicular dipole transition) corroborates the C_(iv) ~β_1 (or C_s ~1A'') symmetry of the excited state accessed at 229 nm, as assigned previously by different groups. For dissociation yielding vibrationless CD_3, the center-of-mass translational energy is, on average, 80% of the maximum energy available. CD_3(v = 0) fragments are produced with a rotational distribution showing a maximum at N'' = 9-11. Evidence for activity of the v_1 symmetric stretching mode of CD_3 is also observed. These results are compared with those obtained for deuterated methyl iodide (ICD_3).