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Isomerization Dynamics of Dicyanine A in n ‐Alcoholic Solution
Author(s) -
Pines Dina,
Goldberg Sinay Y.,
Huppert Dan
Publication year - 1993
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.199300027
Subject(s) - chemistry , picosecond , relaxation (psychology) , excited state , spectroscopy , isomerization , fluorescence , viscosity , ground state , fluorescence spectroscopy , photochemistry , time resolved spectroscopy , conformational isomerism , molecule , atomic physics , thermodynamics , laser , organic chemistry , psychology , social psychology , physics , quantum mechanics , optics , catalysis
The radiationless relaxation of dicyanine A molecules in n ‐alcohols methanol to butanol has been studied by picosecond fluorescence spectroscopy and time‐resolved nonlinear spectroscopy. The fluorescence decay rates have been measured as a function of viscosity, temperature, and fluorescence wavelength. It is shown that the wavelength dependence can be explained by coexistence of two ground‐state conformers. The intrinsic activation barrier for the nonradiative decay from the excited surface is very small, much less than 1 kcal/mol. In a particular solvent the time constants of the nonradiative relaxation show a linear dependence on the variation of viscosity. The experimental data are discussed in relation to the BFO theory (Bagchi, B.; Fleming, G.R.; Oxtoby, D.W. J. Chem. Phys. 1983, 78: 7375).