dc.creator Pant, D. D. en_US dc.creator Kasha, Michael en_US dc.date.accessioned 2006-06-15T13:08:43Z dc.date.available 2006-06-15T13:08:43Z dc.date.issued 1961 en_US dc.identifier 1961-F-8 en_US dc.identifier.uri http://hdl.handle.net/1811/8073 dc.description $^{1}$M. Kasha, Discussions Faraday Soc. 9, 14 (1950). $^{2}$Cf. 1; and also M. Kasha, ""The Nature and Significance of $n-\pi^{*}$ Transitions”, in Light and Life. Johns Hopkins University Press, Baltimore, 1961. $^{3}$H. P. Stephenson, J. Chem. Phys 22, 1077 (1954). $^{4}$J. Rush and H. Sponer, J. Chem. Phys. 20, 1847 (1952). en_US dc.description Author Institution: Department of Chemistry and Institute of Molecular Biophysics, Florida State University en_US dc.description.abstract The well-known absorption of pyridine at 3000--2300) {\AA} has been reexamined in detail. This band was interpreted to consist of three electronic $transitions,^{1}$ on the basis of solvent effect studies by Reid and $Kasha^{2}$ and $Stephenson.^{3}$ The presence of a weak $n-\pi^{*}$ transition in the 2700--3000 {\AA} region was confirmed by the work of Rush and $Sponer^{4}$ who assigned 2875 \AA as the 0,0 band of an allowed $n-\pi^{*}$ transition. In the region 2300--2700 \u{A} the presence of a $\pi-\pi^{*}$ transition required by the experimental evidence and by the analogy with benzene. However, the lack of good spectral resolution has hindered vibrational analysis and an accurate assignment of the 0,0 band .The presence of a second $n-\pi^{*}$ transition in this region has not been confirmed securely. The absorption contours of the strong part of the pyridine 2600 \u{A} absorption in hydrocarbon solvent to which progressively increasing amounts of ethanol are added confirm the presence of two electronic transitions in the 2300--2700 {\AA} region, one of which must be an $n-\pi^{*}$ transition. The absorption contours of pentadeuteropyridine also confirm this analysis: the 2700--3000 {\AA} transition is blue-shifted by $180 cm^{-1}$ in pentadeuteropyridine vapor spectrum, and the band profile is very similar to that of pyridine. The 2300--2700 {\AA} transition undergoes a striking change in hand profile in the vapor spectrum suggesting that two electronic transitions have been shifted differentially in the pentadeuteropyridine. en_US dc.format.extent 150933 bytes dc.format.mimetype image/jpeg dc.language.iso English en_US dc.publisher Ohio State University en_US dc.title ON THE ELECTRONIC TRANSITIONS IN THE NEAR UNTRAVIOLET ABSORPTION BAND OF PYRIDINE en_US dc.type article en_US
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