Beta-carotene |
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| The chemical structure of Beta-carotene 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 Beta-carotene dissolved in hexane. It was measured by R. A. Fuh on summer, 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]. Beta-carotene has a molar extinction coefficient of 139,500 M-1cm-1 at 451 nm [L. Zechmeister, cis-trans Isomeric carotenoids vitamins A and arylpolyenes, Springer-Verlag, 1962]. See also [L. Zechmeister and A. Polgar, "cis-trans Isomerization and spectral characteristics of carotenoids and some related compounds.," J. Am. Chem. Soc., 65, 1522-1528, 1943]. The fluorescence yield of beta-carotene has been estimated to be <0.0001 [R. F. Dallinger, W. H. Woodruff, and M. A. J. Rodgers, "The lifetime of the excited singlet state of $$-carotene: Consequences to photosynthetic light harvesting," Photochem. Photobiol., 33, 275-277, 1981] and [C. Tric and V. Lejeune, "Les carotenes fluorescent-ils?," Photochem. Photobiol., 12, 339-343, 1970]. Accordingly, a fluorescence spectrum was not collected. |
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