The photofragmentation of IJKM) = 11 11) state-selected CD31 was performed at 266 nm. The INK) rotational energy level distribution of the resulting vibrationless CD3 photofragment was determined using ( 2 + 1) resonance-enhanced multiphoton ionization. The INK) distribution showed that the dominant mechanism during the dynamics on the excited 3Q0 surface was A K = 0 scattering between the initially excited parent CD31 and the CD3 fragment, i.e., no relative orbital motion about the original C3 axis of the parent, in agreement with previous non-state selected experiments. In addition, smaller but significant amounts of A K = f 3 scattering also occurred. The outline of a model is provided which attributes the effect of nonhelicity conservation and the A K = f 3 propensity to scattering from regions near the conical intersection between the 3 Q~ and 'QI surfaces and in particular to the coupling term between these surfaces. It is therefore suggested that the relative population of the CD3 INK) energy levels for a given N might provide a quantitative measure of the strength of the nonadiabatic coupling between the two surfaces that correlate asymptotically to the 2P3/2 and 2 P~/ 2 spin-orbit energy levels of the atomic iodine photofragment. The experimental INK) rotational distributions are also compared to two recent quantum calculations and are found to be in good agreement for the total scattering into all K levels for a given N . Experimental evidence is also provided, although not analyzed, for the first observation of a detailed photofragmentation differential cross section.

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A beam of rovibrational energy level selected and magnetic state polarized (X ˜)1 A 1 ) CD 3 I |JKM〉 ≡ |111〉 was photodissociated at 266 nm. State-selective detection of the photoproducts allowed determination of elements of the transition dipole matrix or T matrix. We present here the methodology involved in the extraction of the T matrix elements from such quantum state-to-quantum state experiments and furthermore compare the results to cases where quantum and semiclassical descriptions are expected to be most accurate. A brief description of the effects of nuclear-spin depolarization on the accurate determination of the T matrix elements is also included. After depolarization is taken into account, the magnitudes of the T matrix elements for the R(∆J ) 1) and Q(∆J ) 0) product waves were 6.4 and 6.9, respectively. The relative phase between these waves was (11°, which is due purely to the structure of the excited state potential surface. These T matrix values give a β ) 1.94 for the photodissociation of CD 3 I at 266 nm.

The semiclassical dynamics of a molecule which undergoes tunneling inversion while traversing an electrostatic hexapole field is shown to be described by the motion of a two dimensional harmonic oscillator with angular momentum Lv. Analytical expressions are provided which show explicitly the dependence of Lv on the molecular inversion frequency. A comparison between calculated and experimental focusing curves is also presented.