Application of saturation spectroscopy to the neasurement of C2, 3Pi u concentrations in oxy-acetylene flames

The technique of saturation spectroscopy is applied to measure the concentration of C2 in the 3 Pi(u) state in oxyacetylene flames. The two-level model is further developed and extended for use in intensity regions slightly lower than that required to saturate the resonances completely. As a result, it has proved feasible to measure both the C2 number density in the cited state and an excited-electronic-state lifetime, both of which depend only on the Einstein A coefficient. The experimental setup is described in detail, and possible extensions of the technique to other atomic and molecular systems are discussed.