Fluorescein, ethanol |
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| The chemical structure of Fluorescein, ethanol is shown at the right. The absorption and fluorescence emission spectra are shown below. The structure, absorption, and fluorescence data were all obtained from the PhotochemCAD package by Jonathan Lindsey. This excellent program allows rapid comparison of spectra and enables one to do a variety of photochemically relevant calculations. |
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Absorption
This is a graph of the molar extinction coefficient of Fluorescein dissolved in ethanol. It was measured by R. A. Fuh on 6/20/95 [H. Du, R. A. Fuh, J. Li, A. Corkan, J. S. Lindsey, "PhotochemCAD: A computer-aided design and research tool in photochemistry," Photochemistry and Photobiology, 68, 141-142, 1998]. Fluorescein, ethanol has a molar extinction coefficient of 92,300 M-1cm-1 at 482.5 nm [P. G. Seybold, M. Gouterman, and J. Callis, "Calorimetric, photometric and lifetime determinations of fluorescence yields of fluorescein dyes," Photochem. Photobiol., 9, 229-242, 1969]. The literature fluorescence yield presumably refers to neutral ethanol. The absorption maximum shifts from 484 nm in trifluoroethanol to 520 nm in dimethylsulfoxide [M. M. Martin, "Hydrogen bond effects on radiationless electronic transitions in xanthene dyes.," Chem. Phys. Lett., 35, 105-111, 1975]. The fluorescence maximum shifts from 508 nm to 543 nm across the same solvents and the fluorescence yield declines from 1.0 to 0.60 [M. M. Martin, "Hydrogen bond effects on radiationless electronic transitions in xanthene dyes.," Chem. Phys. Lett., 35, 105-111, 1975]. |
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Fluorescence
This is the fluorescence emission spectrum of Fluorescein dissolved in ethanol. The spectrum was taken by R. A. Fuh on 6/20/95 using an excitation wavelength of 425 nm [H. Du, R. A. Fuh, J. Li, A. Corkan, J. S. Lindsey, "PhotochemCAD: A computer-aided design and research tool in photochemistry," Photochemistry and Photobiology, 68, 141-142, 1998]. The quantum yield is 0.79 [R. E. Kellogg and R. G. Bennett, "Radiationless intermolecular energy transfer. III. Determination of phosphorescence efficiencies.," J. Chem. Phys., 41, 3042-3045, 1964]. |
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