Femtosecond CARS on H-2

Time-resolved non-resonant CARS (coherent anti-Stokes Raman spectroscopy) i s applied to probe H-2 in the gas phase with femtosecond time resolution. T he experimental transients show detailed beating structures, reflecting the rotational dynamics of all thermally populated ground state J levels with high fidelity. Modelling of the experimental data yields temperatures and p ressures with high resolution. The good agreement with values determined by frequency-domain experiments demonstrates the suitability of this method f or the determination of J-dependent collisional-broadening and Line-shiftin g coefficients in gaseous mixtures at high pressures and temperatures, wher e frequency-domain CARS spectra are difficult to model. (C) 1999 Elsevier S cience B.V. All rights reserved.