Triplet-triplet absorption of some organic molecules determined by picosecond laser excitation and time-delayed picosecond light continuum probing

The triplet-triplet absorption cross-section spectra of eosin Y, erythrosin B, rose bengal and C-70 are determined in the wavelength range from 390 to 1600 nm. The T-1 triplet state is populated by S-1-->T-1 intersystem cross ing after singlet state excitation with intense picosecond pump pulses (wav elength 527 nm, duration 6 ps). The triplet-triplet absorption is probed wi th picosecond spectral light continua passing the samples after excited sin glet state relaxation (time delay 20 ns), Absolute triplet-triplet absorpti on cross-sections are obtained by numerical simulation of the absorption dy namics. (C) 1999 Elsevier Science S.A. All rights reserved.