On the analyses of fluorescence depolarisation data in the presence of electronic energy migration. : II. Applying & Evaluating Two-Photon Excited Fluorescence

• Electronic energy migration within a bifluorophoric molecule has been studied by time-resolved two-photon excited (TPE) fluorescence depolarisation experiments. Data were analysed by using a recently developed quantitative approach [Opanasyuk, O. & Johansson, L. B.-Å., On the Analyses of Fluorescence Depolarisation Data in the Presence of Electronic Energy Migration. I. Theory & General Description. Phys. Chem. Chem. Phys., Submitted.]. The energy migration occurs between the 9-anthrylmethyl groups of the bifluorophoric molecule, bis-(9-anthrylmethylphosphonate) bisteroid. These groups undergo local reorientations, while overall tumbling of the bisteroid is strongly hampered in the used viscous solvent, 1,2-propanediol. To solely obtain information about local reorientations of the 9-anthrylmethyl group, also the mono-(9-anthrylmethylphosphonate) bisteroid was studied, which enabled modelling of the ordering potential shape. The analysis of data is partly performed in the Fourier domain and the best-fit parameters are determined by using an approach based on a Genetic Algorithm. The energy migration process was described by an extended Förster theory (EFT). A reasonable value of the distance between the 9-anthrylmethyl groups is found, as well as for the mutual orientation of the ordering potentials. Furthermore, values of the two-photon tensor components were obtained.

Ämnesord

NATURVETENSKAP  -- Kemi -- Fysikalisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Physical Chemistry (hsv//eng)

NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

Nyckelord

Extended Förster theory

Genetic algorithms

Monte Carlo simulations

two-photon excitation

Physical Chemistry

fysikalisk kemi

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