STATIONARY AND TIME-RESOLVED SPECTRA OF 2,2' 5',2''-TERTHIOPHENE/

By analyzing the stationary absorption spectrum of 2,2':5',2 ''-terthi ophene in dichloromethane at room temperature, the zero-zero S-1 --> S -0 transition energy is determined, Time-resolved fluorescence measure ments show that the S-1 --> S-0 radiative relaxation in various solven ts decays exponentially with a common time constant of 170 +/- 10 ps. The fluorescence anisotropy of 2,2':5',2 ''-terthiophene in dichlorome thane is also studied and the transient dichroism is interpreted in te rms of the revolution of a hydrodynamic prolate ellipsoid with the emi ssion dipole aligned parallel to the long molecular axis. (C) 1997 Els evier Science B.V.