Studies of velocity changing collisions using high resolution collision-induced coherent Raman spectroscopy.

Collision-induced coherent Raman resonances between Zeeman sublevels of the ground (3(2)S) state of sodium vapor are observed and characterized. These can be understood in terms of scattering of one incident laser beam from a coherence grating established by two other beams. The principal broadening mechanism for these resonances is the residual Doppler width due to a small angle between the incident beams. Collisional narrowing of the Doppler width is observed in the presence of helium, argon and xenon buffer gases.