MULTIPLEX SPECTROSCOPY - DETERMINING THE TRANSITION MOMENTS AND ABSOLUTE CONCENTRATIONS OF MOLECULAR-SPECIES

A procedure is described that uses two spectroscopic techniques, absor ption and infrared degenerate four-wave mixing, in tandem (multiplex) to measure the transition dipole moments and absolute concentrations o f molecular species in situ. The method is demonstrated by the measure ment of the relative transition moments and concentrations of two diss imilar sample gas components, hydrogen chloride and nitrogen dioxide, but is applicable to a wide variety of molecules and, thus, can provid e new information for transient molecular species. Further, difficulti es in obtaining quantitative information through techniques such as la ser-induced fluorescence, coherent antiStokes Raman scattering, and de generate four-wave mixing spectroscopies can be overcome when a multip lex approach is used.