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Electrochromism and Solvatochromism
Author(s) -
Liptay W.
Publication year - 1969
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.196901771
Subject(s) - solvatochromism , dipole , polarizability , transition dipole moment , bond dipole moment , electric dipole transition , chemistry , absorption (acoustics) , electric field , excitation , ground state , absorption band , moment (physics) , molecular electronic transition , absorption spectroscopy , molecular physics , magnetic dipole , atomic physics , molecule , optics , physics , organic chemistry , quantum mechanics , classical mechanics
The position and the intensity of electronic bands are influenced by an electric field. Pronounced changes in the position of absorption bands are mainly due to the dipole moment of the molecule in the ground state and the change in the dipole moment during the excitation process, and pronounced changes in intensity are due to the field dependence of the transition moment, which can be described by the transition polarizability. The effect of an external electric field on the optical absorption (electrochromism) of suitable molecules can be used to determine the dipole moment in the ground state, the change in dipole moment during the excitation process, the direction of the transition moment of the electronic band, and certain components of the transition polarizability tensor. These data largely determine the strong solvatochromism (solvent‐dependence of the position and intensity of electronic bands), which is observed in particular with molecules having large dipole moments. Smaller contributions to solvatochromism result from dispersion interactions, which predominate in the case of nonpolar molecules. The models developed have been experimentally checked and verified by a combination of electro‐optical absorption measurements (influence of an external electric field on absorption) and investigation of the solvent‐dependence of the electronic bands.