Raman spectroscopy of supersonic jets of CO2: Density, condensation, and translational, rotational, and vibrational temperatures

The links between translational, rotational, and vibrational temperatures of supersonic molecular jets, and their density and degree of condensation, are discussed in terms of quantitative Raman scattering experimental data. Such links are established as the result of energy and momentum conservation laws, and of the collisional regime in the jet. Four representative supersonic expansions of CO2, generated at different stagnation pressures are analyzed, showing the potential of quantitative Raman spectroscopy for a complete characterization of the jet.