SOLVATION DYNAMICS OF RHODAMINE-800 IN WATER AND D2O

Time-resolved resonance heterodyne optical Kerr-effect spectroscopy is employed to measure the solvation dynamics of rhodamine 800 in water and D2O. Unlike other large dye molecules, rhodamine 800 solvation dyn amics in water exhibits a long-time component which we attribute to hy drogen-bond formation (breaking). We also find a rather unusual large isotope effect which does not exist in other dyes. An important part o f the experimental data is a bimodal solvation correlation function wi th an ultrafast femtosecond component < 100 fs.