Knowledge Bank

An interference between certain components of dipole moment transition amplitudes as induced through collisions is found to be phase-correlated with those induced through subsequent collisions of the same HD molecules with foreign gas atoms. This interference leads to collisionally induced sharp spectral features having shapes which arise in a manner similar to Ramsey double resonance. These features, which depend only upon scalar functions of intermolecular displacements, will be compared with quite differently appearing features in the vibration-rotation specturm of $H2$ arising from an intercollisional interference between dipoles generated in successive collisions associated with vector functions of the intermolecular displacements. Comparison with experiment will be made, and ramifications of the vector intercollisional interference mechanism in Raman spectroscopy will be discussed.