Orientation as a probe of photodissociation dynamics

Abstract

Molecular chlorine (Cl₂) was photodissociated in the wavelength range 270–400 nm with linearly polarized light, and the orientation of the excited-state chlorine atom Cl*(²P_1/2) was measured by 2+1 resonance enhanced multiphoton ionization (REMPI) using circularly polarized light. The degree of orientation of the Cl* photofragment is found to oscillate as a function of photolysis wavelength. The oscillation is a result of quantum mechanical coherence arising from electronic states of different symmetry that correlate to the same separated-atom asymptote. A simple curve-crossing model using abinitio potential energy curves reproduces the general shape of the oscillation but fails to give a quantitative fit.