ABSTRACT
Cavity ringdown (CRD) spectroscopy is an advanced optical absorption technique that combines selectivity and sensitivity with the potential for inherent quantitative calibration, thus enabling direct quantitative measure ment of chemical intermediate species concentrations in a flame. Absorption is an especially useful technique for species that are otherwise not easy to detect with other optical methods, e.g., predissociative radicals that do not fluoresce. CRD is an absorption technique with the sensitivity to detect the small concentrations of species that are intermediate in the chemical mechanism that converts fuel and oxidizer to combustion products. For investigations of detailed chemistry in laminar flames, the quantitative col umn density from CRD is a powerful complement to fluorescence methods (see Chapter 2).
