Picosecond polarization-selective transient grating experiments in sodium-seeded flames

Polarization-selective transient grating experiments have been used to study the subnanosecond time scale dynamics of several sodium-seeded, premixed flames. Intensity gratings (in which both excitation beams are of the same polarization) were used to determine excited-state quenching collision rates, while polarization gratings (in which the excitation beams are cross polarized) were used to measure Na diffusion constants and the rates of Na ground state magnetic sublevel population scattering collisions. In addition, the rates of scattering between the 3P1/2 and 3P3/2 excited state levels were measured using an excited state probing scheme.