dc.creator Sztainbuch, I. en_US dc.creator Leroi, G. E. en_US dc.date.accessioned 2006-06-15T18:25:45Z dc.date.available 2006-06-15T18:25:45Z dc.date.issued 1989 en_US dc.identifier 1989-WG'-3 en_US dc.identifier.uri http://hdl.handle.net/1811/18034 dc.description $^{\ast}$Research supported in part by the U.S. National Science Foundation $^{1}$ J. Friedman and R. M. Hochstrasser, Chem. Phys. Lett. 32, 414 (1975) $^{2}$ R. R. Birge and H. L. Fang, private communication $^{3}$ J. S. Horwitz, T. Itoh, and B. E. Kohler, J. Chem. Phys. 87. 2433 (1987) en_US dc.description Author Institution: Department of Chemistry and the LASER Laboratory, Michigan State University en_US dc.description.abstract For centrosymmetric chromophores, such as linear polyencs, approximately half of the electronic excited state manifold is inaccessible from the ground state by conventional absorption spectroscopy because of parity selection rules. Such hidden'' states are typically studied by two-photon induced fluorescence spectroscopy, or by high resolution absorption and fluorescence excitation spectroscopy of samples placed an a Shpolskii matrix environment. In cases where these techniques are not applicable, (e.g. non-fluorescent molecules), preresonance Raman spectroscopy may be a suitable alternative. The preresonance Raman excitation profile is determined point-by-point from the ratio of the scattered intensity of a sample vibrational band to that of a nearby solvent mode as a function of the excitation energy, and the hidden states manifest themselves as interference $features.^{1}$ However, the interpretation of the interference features, and their relationship to the hidden state origin, which is not active in the excitation profile, rely on self-consistency arguments. In an effort to establish more firmly the utility of preresonance Raman profiles, we have chosen diphenyldecapentaene (DPDP) as a model compound. The low-lying, hidden $2^{1}Ag$ state origin of DPDP has been located at low temperatures by both two-photon $excitation^{2}$ and matrix absorption/$emission^{3}$ spectroscopy. We present here the preresonance Raman excitation profile of DPDP in the region just below the allowed $^{***} B_{u}$ electronic state, in the $20000-22700 cm^{-1}$ energy range. The results are in excellent $accord^{1}$ with those of the more direct methods, and establish preresonance Raman excitation as a viable technique for locating parity-forbidden electronic states. en_US dc.format.extent 101067 bytes dc.format.mimetype image/jpeg dc.language.iso English en_US dc.publisher Ohio State University en_US dc.title PRERESONANCE RAMAN EXCITATION PROFILES: COMPARISON WITH MORE DIRECT PROBES OF DIPOLE-FORBIDDEN EXCITED ELECTRONIC $STATES^{\ast}$ en_US dc.type article en_US
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