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Proceedings Paper

Coumarin fluorescent probes by electro-optical and laser spectrofluorimetry methods
Author(s): Nicolai A. Nemkovich; Wolfram Baumann; Heribert Reis; Yurii V. Zvinevich
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Paper Abstract

Modified electro-optical absorption and emission methods were used to measure the dipole moments of six coumarin fluorescent probes (CU1, CU4, CU7, CU30, CU120, CU334) in the equilibrated ground, excited Franck-Condon and equilibrated excited states. The measurements were performed in cyclohexane and dioxane at room temperature. The equilibrated ground and excited states dipole measured by electro-optical methods are compared with those derived from other measurements techniques and from semiempirical calculations. Experiments and calculations performed in this work reveal a set of anomalous and interesting properties of CU7 and CU30 in solutions. The spectral dependence of some electro-optical coefficients and, consequently, dipole moments in excited Franck-Condon state indicates that the absorption band is a superposition of several (at least two) electronic transitions. Most probably there are two close- lying singlet electronic states which contribute to the first absorption band. Our electro-optical and laser spectrofluorimetry measurements do not support the formation of twisted intramolecular charge transfer state after optical excitation in the studied coumarins, at least in cyclohexane and dioxane.

Paper Details

Date Published: 7 May 1997
PDF: 10 pages
Proc. SPIE 2980, Advances in Fluorescence Sensing Technology III, (7 May 1997); doi: 10.1117/12.273543
Show Author Affiliations
Nicolai A. Nemkovich, B.I. Stepanov Institute of Physics (Belarus)
Wolfram Baumann, Univ. of Mainz (Germany)
Heribert Reis, Univ. of Mainz (Germany)
Yurii V. Zvinevich, B.I. Stepanov Institute of Physics (Belarus)

Published in SPIE Proceedings Vol. 2980:
Advances in Fluorescence Sensing Technology III
Richard B. Thompson, Editor(s)

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