Coherent amplification in fluorescent dye solutions. II. The inverse pre-resonance Raman spectrum of rhodamine 6G

Inverse pre-resonance Raman spectra of rhodamine 6G in solution in methanol have been recorded over the concentration range 10^?1 to 10^?4 mol ?^?1. The solute and solvent transitions are found to display perfectly normal lorentzian profiles over the whole of this concentration range. Intensities and depolarization ratios of the pre-resonance Raman features are recorded. It is shown that the spectra arise from monomeric rhodamine 6G molecules in the singlet electronic ground state and the relative merits of the CARS and inverse Raman methods for recording resonance Raman spectra are discussed.