Solvation dynamics in ethanol were studied by measuring the time-resolved Stokes shift of the emission from the twisted intramolecular charge-transfer state of bis(4-(methylamino)phenyl) sulfone (DMAPS). The time scale of the spectral relaxation, τS, was determined from 0 to -60°C. Near 0°C, τS is comparable to the longitudinal relaxation time of the solvent, τL, in agreement with predictions based on dielectric continuum models. However, with decreasing temperature, τS falls between τL and the Debye rotational relaxation time, τD. The deviations of the solvation times from that predicted by a continuum model for the solvent are discussed in terms of molecular details of the solvent which are not included in the simple continuum descriptions.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry