Vibrationally selective radiative and non-radiative transitions in gaseous hydrogen molecules

An efficient vibrationally selective technique to build-up the v″ = 1 vibrational levels in gaseous hydrogen is demonstrated using stimulated Raman pumping (SRP). Both photo-acoustic Raman spectroscopy (PARS) and coherent anti-Stokes Raman spectroscopy (CARS) are used to study non-radiative and radiative (v″ = 0 and v″ = 1) transitions in gaseous H2 molecules. The population fraction in the v″ = 1 vibrational level has been estimated using combined photo-acoustic and coherent anti-Stokes Raman spectroscopy with stimulated Raman pumping.

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► Environmental pollution problems: continuous monitoring of the leakage of inflammable gases is also required, such as H2, CH4 and H2S, chemical plants and along gas pipe-lines for health and safety reasons.
► PARS and CARS laser spectroscopic technique with SRP.
► It is particularly advantageous since a tunable infra-red laser is not required.
► Application in Combustion diagnostic Engineering and Technology.