Molecular photodissociation by an ultraviolet photon

The laser has greatly expanded the study of photodissociation dynamics. By generating large concentrations of fragments using monochromatic light, the laser enables the measurement of their final state distribution. This distribution over translational, vibrational, and rotational states combined with the conservation of energy and linear and angular momentum allows us, in principle, to calculate the forces acting in the excited state. A review of experimental results so far obtained shows that: 1) for diatomics the quantum states of the dissociated atoms can now be directly determined, 2) for triatomics the excess of photon energy over dissociation energy appears in comparable amounts in vibrational and translational energy with rotational energy often substantial as well (ICN and H2S are exceptions), 3) in complex molecules optical energy is absorbed in one part of the molecule and utilized in another with resulting intramolecular transfer of energy.