dc.creator Knight, Alan E. W. en_US dc.creator Parmenter, C. S. en_US dc.date.accessioned 2006-06-15T17:02:44Z dc.date.available 2006-06-15T17:02:44Z dc.date.issued 1973 en_US dc.identifier 1973-Delta-02 en_US dc.identifier.uri http://hdl.handle.net/1811/15963 dc.description Author Institution: Department of Chemistry, Indiana University en_US dc.description.abstract Emission with a low quantum yield ($<$1\%) has been observed after exciting each of several bands in the electric dipole forbidden 3200 \AA absorption system $(^{1}E^{\prime\prime}\longleftarrow ^{1}A_{1})$ of s-triazine vapor. This now leaves pyridine as the only one of the six well known azabenzenes from which vapor emission has not been observed. Emission from 0.5 torr of s-triazine is fluorescence only, and its structure is consistent with that expected from the single vibronic level in the $^{1}E^{\prime\prime}$ state pumped in excitation. The fluorescence spectrum from the level $6^{1}$ is particularly simple. The intensity is induced principally by the $e^{\prime}$ ring distortion $\nu_{6}$ appearing in the vibronic origins $6_{0}^{1}$ and $6_{2}^{1}$ This mirrors the activity in vapor absorption, but other significant vibronic origins seen in absorption are of reduced importance. Long progressions in the symmetric ring breathing mode $\nu_{12}$ are built on the $\nu_{6}$ fluorescence origins giving information on the Franck-Condon development which in absorption is obscured by conjestion. The fluorescence is quenched by added gases such as isopentane. By analogy with the known behavior of glyoxal, pyrazine, and other molecules, this is indicative of collision-induced triplet formation. However, no phosphorescence can be observed after fluorescence quenching. If triplet formation does occur, this suggests that the lowest triplet in the vapor is the $^{3}E^{\prime\prime}$ state predicted by Hochstrasser to be nonemitting. en_US dc.format.extent 245084 bytes dc.format.mimetype image/jpeg dc.language.iso English en_US dc.publisher Ohio State University en_US dc.title SINGLE VIBRONIC LEVEL FLUORESCENCE FROM THE $^{1}E''(S_{1})$ STATE OF s-TRIAZINE en_US dc.type article en_US
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