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dc.creatorSackett, Philip B.en_US
dc.creatorYardley, James T.en_US
dc.descriptionAuthor Institution: Department of Chemistry, University of Illinoisen_US
dc.description.abstractA tunable organic dye laser has been used as a narrow band $(\sim 0.8 {\AA})$ radiation source to excite $NO_{2}$ molecules under essentially collision-free conditions in the spectral range 4510 --- 4610 {\AA}. The fluorescence which is observed in a very large cell is decidely non-exponential, so that the decay function for each experiment is characterized as both non-exponential and exponential, the latter for purposes of comparison with other experiments and for purposes of discussion in standard terms. The lifetimes which are obtained in this way show a marked structural pattern when displayed as a spectrum, with individual values ranging from 62 $\mu $ sec to 75 $\mu $ sec for observation of fluorescence at wavelengths longer than 5200 {\AA}. In addition, the dependence of lifetime and non-exponentiality, as well as their spectral variations, on observation wavelength, pressure, and fluorescence observation geometry have been investigated over a shorter spectral region. A small amount of high resolution spectral data is reported which seems to indicate the presence of some unresolved, quasi-continuous absorption underlying the obvious bands of the visible spectrum. The effects of restrictive fluorescence measurement geometry on lifetime measurement have been explored, with particular attention to other investigations, for which the shorter, non-varying lifetime observations may be explained. Finally the observed dynamics and spectroscopy of $NO_{2}$ are discussed in terms of the following hypotheses: (1) transitions to both the $^{2} B_{1}$ and $^{2} B_{2}$ electronic states occur together over a large portion of the visible spectrum, (2) both of these excited states are clearly perturbed, and (3) the $^{2} B_{2}$ transition is the stronger of the two. Philip B. Sackett has been a National Science Foundation Predoctoral Fellow, 1967--1971. He is presently located at Air Force Cambridge Research Laboratories, L. G. Hanscom Field, Bedford, Massachusetts 01730.en_US
dc.format.extent235986 bytes
dc.publisherOhio State Universityen_US

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