engleski

Determination of collisional line broadening coefficients with femtosecond time-resolved CARS

The potential of femtosecond time-resolved CARS for the determination of J-dependent line broadening coefficients is demonstrated. With the well-developed femtosecond technique the line broadening coefficients of the H2 Q-branch ro-vibrational transitions are measured in pure H2 and in H2 + He and H2 + N2 mixtures. The results for pure H2 show excellent agreement with the values obtained by other groups using high-resolution CARS in the wavenumber domain. The dependence of the experimental broadening on perturber density also shows good agreement with the behavior of broadening found in the literature: a linear dependence in the case of hydrogen and helium as perturber and explicit non-linear behavior in the case of nitrogen. The role of inhomogeneous broadening in time domain CARS is discussed.

collisional line broadening; femtosecond time-resolved CARS

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