Picosecond transient absorption of xanthene dyes

After one- and two-colour ps-excitation the transient absorption of rose be ngal, erythrosin B and eosin Y in the spectral range from 450 to 670 nm was probed using picosecond continuum pulses generated in H2O-D2O mixture. Our experiments showed for all dyes a high T-1-T-n absorption signal above 590 nm where no ground state absorption occurs. These excited triplet states c an be effectively populated by a delayed second pump pulse. Their propertie s with special attention to reverse intersystem crossing processes from T-n to S-x are discussed.