TRANSIENT SPECTROSCOPY OF TRIPHENYLMETHANE DERIVATIVES FOLLOWING SUBPICOSECOND IRRADIATION

Time-resolved absorption spectra of triphenylmethane dye solutions are measured in the 320-750 nm wavelength range in pump-probe experiments with subpicosecond resolution. The observed spectral evolution occurs at a rate which depends on solvent viscosity. The transient spectra are described by the superposition of the absorption and/or gain spectra of the states S(o) and S1, and of an intermediate state S(x) involved in the relaxation process. The results indicate that the S(x) absorption spectrum is similar to that of S1 but blue-shifted.