dc.creator Müller, Christian en_US dc.creator Schroeder, Jorg en_US dc.creator Troe, J. en_US dc.date.accessioned 2008-01-12T13:50:32Z dc.date.available 2008-01-12T13:50:32Z dc.date.issued 2007 en_US dc.identifier 2007-FD-08 en_US dc.identifier.uri http://hdl.handle.net/1811/31366 dc.description Author Institution: Department of Chemistry, Purdue University, West Lafayette, IN 47907-2084; Institut fur Physikalische Chemie, Georg-August-Universitat Gottingen, Germany en_US dc.description.abstract Static and dynamic fluorescence properties of the $\mathrm{S}_1$\,$\leftarrow$\,$\mathrm{S}_0$ transitions of three intramolecularly hydrogen-bonded molecules, 1,8-dihydroxyanthraquinone (1,8-DHAQ), 1-aminoanthraquinone (1-AAQ) and 9-hydroxyphenalenone (9-HPA), were investigated using Fluorescence Excitation Spectroscopy (FES) and Time-correlated Single Photon Counting in order to assess spectroscopic evidence indicating the occurrence of excited-state intramolecular proton transfer (ESIPT) and the types of potentials governing the intramolecular hydrogen bonding. Moreover, ab initio calculations were performed on one-dimensional hydrogen transfer potential energy curves for both $\mathrm{S}_0$ and $\mathrm{S}_1$ states at different levels of theory. As to 1-AAQ, the uniform excess energy dependence of the comparatively long fluorescence lifetimes, which can quantitatively be accounted for according to Fermi's Golden Rule, suggests that the energy- and time-resolved fluorescence properties are associated with a single-minimum-type potential. The non-radiative relaxation mechanism is attributed to internal conversion to the $\mathrm{S}_0$ state. These findings are also in line with calculations based on the quantum theory of atoms in molecules (QTAIM). The FES of 1,8-DHAQ exhibits two distinct excess energy ranges which are characterized by different spectral congestions and relative intensities in the frequency-domain measurements and by different fluorescence lifetimes in the time-domain measurements. In agreement with previous findings, we suggest that the fluorescence bands below $\sim$\,$600\,\mathrm{cm}^{-1}$ are due to transitions originating in the 9,10-quinone well, while the bands above $\sim$\,$600\,\mathrm{cm}^{-1}$ are due to transitions originating in the proton-transferred 1,10-quinone well. For 9-HPA, only the frequency-domain measurements give tentative evidence as to the presence of a pronounced double-minimum-type potential. The rapid non-radiative relaxation mechanism as revealed by fluorescence lifetime measurements is attributed to intersystem crossing to a triplet state. en_US dc.language.iso English en_US dc.publisher Ohio State University en_US dc.title INTRAMOLECULAR HYDROGEN BONDING IN 1,8-DIHYDROXYANTHRAQUINONE, 1-AMINOANTHRAQUINONE AND 9-HYDROXYPHENALENONE STUDIED BY PICOSECOND TIME-RESOLVED FLUORESCENCE SPECTROSCOPY IN A SUPERSONIC JET en_US dc.type article en_US
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