화학공학소재연구정보센터
Journal of Physical Chemistry A, Vol.101, No.32, 5729-5735, 1997
Relaxation of Inhomogeneous Spectral Band-Width of Dye Molecules in Polar-Solvents Studied by Time-Resolved Hole and Fluorescence Spectroscopy
The comparative studies for time-resolved ground state hole spectra and time-resolved fluorescence spectra of dye molecules in polar solvents have been investigated. A marked difference has been shown clearly in the relaxation times between that are observed from the spectral band width, the solvent fluctuation around average energy, and that from the lime resolved peak shift, the average of the solute-solvent interaction energy. The time correlation function of the solvent relaxation observed from the spectral band width was much slower than that from the time dependent peak shift in a fluid solvent at higher temperature, but they became comparable at lower temperature. Some possible mechanisms are discussed for understanding of the time dependences of the behavior. At room temperature, due to the relative preponderance of the rotational diffusion over the translational diffusion of solvent molecules, the energy relaxation takes precedence over the relaxation of the orientational distribution. It is emphasized that the relaxational mechanism presented here is applicable for both the time-resolved fluorescence and the ground state hole spectra.