@misc{LoehmannsroebenKantorKumkeetal.2005, author = {L{\"o}hmannsr{\"o}ben, Hans-Gerd and Kantor, Zoltan and Kumke, Michael Uwe and Schm{\"a}lzlin, Elmar and Reich, Oliver}, title = {OPQS - optische Prozess- und Qualit{\"a}ts-Sensorik}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-13205}, year = {2005}, abstract = {Im vorliegenden Beitrag wird an Hand dreier Beispiele der Einsatz von optischer Sensorik zur Produktcharakterisierung dargestellt, n{\"a}mlich Untersuchungen zum O2-Gehalt in Fruchts{\"a}ften, zur Isotopiesignatur von CO2 in Mineralw{\"a}ssern und zu Lichtstreueigenschaften eines Sonnenschutzmittels. Inhalt: Bestimmung von O2 mit Lumineszenzsonden Isotopenselektive Bestimmung von CO2 mit TDLAS Optische Charakterisierung stark streuender Materialien mit Photonendichtewellen}, language = {de} } @misc{DoscheKumkeLoehmannsroebenetal.2004, author = {Dosche, Carsten and Kumke, Michael Uwe and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Ariese, F. and Bader, Arjen N. and Gooijer, C. and Miljanic, O. S. and Iwamoto, M. and Vollhardt, K. Peter C. and Puchta, R. ; van Eikema Hommes, N. J. R.}, title = {Deuteration effects on the vibronic structure of the fluorescence spectra and the internal conversion rates of triangular [4]Phenylene}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-11881}, year = {2004}, abstract = {Deuteration effects on the vibronic structure of the emission and excitation spectra of triangular [4]phenylene (D3h[4]phenylene) were studied using laser-excited Shpolskii spectroscopy (LESS) in an octane matrix at 4.2 K. For correct assignment of the vibrational modes, the experimental results were compared with calculated frequencies (B3LYP/6-31G*). CH vibrations were identified by their characteristic isotopic shifts in the spectra of deuterated triangular [4]phenylenes. Two CC stretching modes, at 100 cm-1 and 1176 cm-1, suitable as probes for bond strength changes in the excited state, were identified. The isotope effect on the internal conversion rates of triangular [4]phenylene was evaluated from measurements of temperature dependent lifetime. Isotope dependency and the magnitude of the internal conversion rates indicate that internal conversion in triangular [4]phenylene is most likely induced by CH vibrations. The results obtained by LESS and lifetime measurements were compared with PM3 PECI calculations of the excited state structure. The theoretical results and the relation between ground and excited state vibration energies of the 1176 cm-1 probe vibration indicate a reduction of bond alternation of the central cyclohexatriene ring in the excited state.}, language = {de} } @misc{DoscheKumkeArieseetal.2003, author = {Dosche, Carsten and Kumke, Michael Uwe and Ariese, F. and Bader, Arjen N. and Gooijer, C. and Dosa, P. I. and Han, S. and Miljanic, O. S. and Vollhardt, K. Peter C. and Puchta, R. and Eikema Hommes, N. J. R. van}, title = {Shpol'skii spectroscopy and vibrational analysis of [N]phenylenes}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-13075}, year = {2003}, abstract = {Vibrationally resolved fluorescence spectra of four angular [N]phenylenes were recorded with laser excited Shpol'skii spectroscopy (LESS) in an n-octane matrix at 10 K. In general, the same vibrational frequencies were observed in the fluorescence excitation and emission spectra, indicating that the geometries of ground and electronically excited state are very similar. Because of intensity borrowing from the S2 state, vibrations of two different symmetries were observed in the fluorescence excitation spectra of angular [3]phenylene and zig-zag[5]phenylene. This finding allowed the location of the S2 state for these compounds. DFT calculations(RB3LYP/6-31G*) of the ground state vibrational frequencies were made. The calculated vibrational modes were in reasonably good agreement with the experimental data. A new very low-frequency vibration of approximately 100 cm-1 was predicted and experimentally confirmed for all [N]phenylenes investigated. This vibration seems to be unique for [N]phenylenes and is attributed to an in-plane movement of the carbon backbone.}, language = {de} } @misc{FrimmelKumke1998, author = {Frimmel, Fritz Hartmann and Kumke, Michael Uwe}, title = {Optische Parameter zur Stoffcharakterisierung vom Trinkwasser bis zum Abwasser}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-13088}, year = {1998}, abstract = {Die Anwendung von optischen Parametern zur Stoffcharakterisierung wird diskutiert. Dabei ist der Schwerpunkt der Diskussion auf absorptions- und fluoreszenzspektroskopische Methoden gesetzt. Beide Methoden k{\"o}nnen schnell und zuverl{\"a}ssig - auch im on-line Betrieb - eingesetzt werden. Der Beitrag soll einen {\"U}berblick {\"u}ber die grundlegenden M{\"o}glichkeiten der Anwendung beider Methoden geben.}, language = {de} }