Mainz 1997 – wissenschaftliches Programm

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MO: Molekülphysik

MO 17: Spektroskopie

MO 17.2: Vortrag

Donnerstag, 6. März 1997, 14:15–14:30, P3

Time-resolved multi-photon induced anisotropic fluorescence using time-correlated single-photon counting technique. — •Andreas Volkmer, David Hatrick, and David J. S. Birch — University of Strathclyde, Department of Physics and Applied Physics, John Anderson Building, 107 Rottenrow, Glasgow, G4 0NG, Scotland, UK

Detection of fluorescent probe molecules in solution is demonstrated using 140 fs pulses to achieve molecular excitation by simultaneous absorption of two and three near infrared photons. The emission spectra, intensity decay, and rotational correlation times, using the TCSPC technique, were found to be identical as compared to one-photon excitation. However, the time-zero anisotropy observed was larger than for one-photon excitation in both cases, indicating an increased orientation photoselection of excited molecules after multi-photon absorption [1]. The results reveal the potential of this method to study with increased sensitivity the structure and dynamics of microheterogeneous systems (i.e. biomembranes, porous matrices) doped with probe molecules. [1] J. Lakowicz, I Gryczynski, E. Danielsen, Chem. Phys. Lett., 191 No.1,2 (1992) 47