Variation of fragment anisotropy parameters along asymmetric resonances in OH photodissociation. A quantum-mechanical study

Quantum mechanical analysis is presented for the anisotropy parameters of O(3Pj, j = 0, 1, 2) resulting from the photodissociation of OH. The angular distributions are predicted to be isotropic along Lorentzian resonances, because of the long lifetimes. The anisotropy parameters exhibit strong variations across asymmetric resonances due to the quantum interference between the binding A 2Σ+ and the dissociative 2Σ− states. It is also discussed that control of the photodissociation processes may be achieved simultaneously through selecting photofragments branching ratios and through angular resolution of the photofragments, simply by varying the excitation wavelength near the asymmetric resonances.