Zee Hwan Kim, Andrew J. Alexander, S. Alex Kandel, T. Peter Rakitzis and Richard N. Zare
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*(2P1/2) 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.