Photofragments angular distribution

Figure 2-1. A schematic diagram of the apparatus used to record photofragment angular distributions of complexes. An F-center laser is used to pump transitions in the parent complex which leads to dissociation. A second F-center laser is used as a probe to state selectively detect the fragments. The electrodes are used to orient the parent molecules prior to excitation.

Eqs. (6.4) and (6.5) lead to the cylindrical symmetry of the final photofragment angular distribution W(0f, pf) in the form of a dumbbell and a toroid, which are symmetrical with respect to the E-vector (the 2-axis). The distribution W(0f,ipf) is proportional to a differential photodissociation cross-section in the laboratory frame, f(0f,(fif) = daph/dO. For a proper description of its symmetry properties it is usually [376, 402] expanded in a set of spherical harmonics Ykq The cylindric symmetry in this case means that only spherical functions Too and Y20 appear with non-zero coefficients, and then... 

Zare, R.N. (1989). Photofragment angular distribution from oriented symmetric-top precursor molecules, Chem. Phys. Lett., 156, 1-6. 

The photofragment angular distribution can indicate the electronic symmetry of the predissociating state (Zare, 1972). 

As pointed out in our previous paper on the state-to-state photodissociation of HF dimer , photofragment angular distributions can be used in favorable cases to determine the final internal state distribution of the fragments. The kinematics also can be used to determine the correlations between the rotational states of the two fragments. That is to say the relative rates can be determined for... 

D. C. Dayton, K. W. Jucks, and R. E. Miller,/. Chem. Phys., 90,2631 (1989). Photofragment Angular Distributions for HF Dimer. Scalar J-J Correlations in State-to-State Photodissociation. 

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