TY - JOUR
T1 - Dipole solvation in nondipolar solvents
T2 - Experimental studies of reorganization energies and solvation dynamics
AU - Reynolds, L.
AU - Gardecki, J. A.
AU - Frankland, S. J.V.
AU - Horng, M. L.
AU - Maroncelli, M.
PY - 1996/6/13
Y1 - 1996/6/13
N2 - Steady-state and time-resolved emission measurements of the solvatochromic probe coumarin 153 are used to study solvation of a dipolar solute in nondipolar solvents such as benzene and 1,4-dioxane. Contrary to the predictions of dielectric continuum theories, the Stokes shifts (or nuclear reorganization energies) that accompany electronic excitation of this solute are substantial in such solvents (∼1000 cm-1). The magnitudes of the shifts observed in both nondipolar and dipolar solvents can be consistently understood in terms of the relative strength of the interactions between the permanent charge distributions of the solute and solvent molecules. (Information concerning these charge distributions is derived from extensive ab initio calculations on the solute and 31 common solvents.) The dynamics of solvation in nondipolar solvents, as reflected in the time dependence of the Stokes shifts, is qualitatively like that observed in polar solvents. But, whereas the dynamics in polar solvents can be rather simply modeled using the solvents dielectric response as empirical input, no simple theories of this sort are currently capable of predicting the solvation dynamics in nondipolar solvents.
AB - Steady-state and time-resolved emission measurements of the solvatochromic probe coumarin 153 are used to study solvation of a dipolar solute in nondipolar solvents such as benzene and 1,4-dioxane. Contrary to the predictions of dielectric continuum theories, the Stokes shifts (or nuclear reorganization energies) that accompany electronic excitation of this solute are substantial in such solvents (∼1000 cm-1). The magnitudes of the shifts observed in both nondipolar and dipolar solvents can be consistently understood in terms of the relative strength of the interactions between the permanent charge distributions of the solute and solvent molecules. (Information concerning these charge distributions is derived from extensive ab initio calculations on the solute and 31 common solvents.) The dynamics of solvation in nondipolar solvents, as reflected in the time dependence of the Stokes shifts, is qualitatively like that observed in polar solvents. But, whereas the dynamics in polar solvents can be rather simply modeled using the solvents dielectric response as empirical input, no simple theories of this sort are currently capable of predicting the solvation dynamics in nondipolar solvents.
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M3 - Article
AN - SCOPUS:33646102263
VL - 100
SP - 10337
EP - 10354
JO - Journal of Physical Chemistry
JF - Journal of Physical Chemistry
SN - 0022-3654
IS - 24
ER -