BMOLogo

Dr. Uwe Megerle
Ex former PhD student


LMU München
Fakultät für Physik


Home

General
Research
Funding
Members
Publications
Lectures/Seminars
Conferences
Vacancies
Search

Internal




Impressum
(c) 2002 BMO

Dear visitor,

welcome to my website at the Institute for BioMolecular Optics of the LMU Munich. Here you can find a brief overview of my scientific interests and some information about myself.

Recent research projects
  • Sub-50 fs broadband transient absorption spectroscopy:
    The two pump-probe spectrometers operated in our lab combine all state-of-the-art concepts and components, from mechanics over optics to software codes for data recording and processing. The combination of prism-based polychromators and the multiplex detection (CCD or PDA sensor) allows for the effective exploitation of the spectrally ultrabroad probe pulses generated in CaF2. For details, see here.

  • LED-based quantitative illumination setup:
    In visible light photocatalysis, the use of high power LEDs as light sources has become increasingly popular. Our setup allows for a defined illumination and an accurate determination of the number of absorbed photons. With subsequent chemical analysis of the absolute chemical yield of photoproducts, the overall quantum yield of the photoreaction can easily be calculated.

  • Flavin photocatalysis studied with TA spectroscopy from sub-pic- to nanoseconds:
    In cooperation with the groups of Prof. B. Knig and Prof. B. Dick in Regensburg we showed that the photooxidation of benzylic alcohol to benzaldehyde proceeds via the triplet state of the flavin catalyst. In pure substrate solution, we observe a fast forward (~4 ps) and backward (50 ps) electron transfer between the excited flavin and the benzylic alcohol without significant product formation. In the triplet manifold, the charge recombination is spin-forbidden and the required proton transfer can compete with the unproductive relaxation to the ground state.

  • Experimental study of the ultrafast dynamics of molecular switches:
    After UV-excitation, the closed form of spironaphtoxazine (SNO) undergoes a rapid conformational reorientation towards an open merocyanine form. We studied this photoreaction by monitoring the absorption changes on the timescale from ~100 fs to 1 ns and thereby determined the rate constants for the successive steps.

  • Electron transfer in triarylboranes (TABs):
    In cooperation with the group of Prof. C. Lambert in Würzburg we examined two organic boron compounds suitable for the application in organic light emitting diodes (OLEDs). We were specifically interested in the interaction between the UV-excited TABs and the surrounding solvent molecules. By monitoring the shift of the stimulated emission with time we found that the solvation dynamics depend on the symmetry of the solute: The availability of several active sites in the highly symmteric TCB accelerates the overall solvation compared to CB by rendering the excitation mobile.

  • Flavin-induced DNA photooxidation and charge movement:
    Substantial quantum yields of long-lived charge separated states are found in DNA double strands with an incorporated flavin chromophore (cooperation with Prof. T. Carell, LMU Munich). The photoexcitated flavin state is quenched by electron transfer from neighboring DNA bases. Depending on the DNA sequence, the positive charge can be trapped in multiple-(dG:dC)-sites which prevent the picosecond charge recombination.

  • Solvent-driven photoinduced intramolecular electron transfer in crystal violet lactone:
    This project is a completion of the work of Uli Schmidhammer and our collaborator Jerzy Karpiuk (Warsaw, Poland). They have studied in detail the electron transfer in different lactonic forms of triarylmethane dyes, a class of donor-acceptor molecules.
    Compare also: Electron transfer in lactones
  •  

    Current position

    After my PhD I was seeking new challenges in industry and started working as an optics developer at SCANLAB in Puchheim, Germany.



    (no picture available)
    Telephon:
    +49-89-2180-9258 (Office)
    +49-89-2180-9283 (Lab)
    E-Mail: uwe.megerle(at)physik.uni-muenchen.de

    Curriculum Vitae


    Recent BMO Publications:

    Unraveling the flavin-catalyzed photooxidation of benzylic alcohol with transient absorption spectroscopy from sub-pico- to microseconds (details).

     

    Photoinduced molecular dynamics inincreasingly complex systems: From ultrafast transient absorption spectroscopy to nanoscopic models (details).

     

    Flavin-induced DNA Photooxidation and Charge Movement Probed by Ultrafast Transient Absorption Spectroscopy (details).

     

    Influence of core-substitution on the ultrafast charge separation and recombination in arylamino core-substituted naphthalene diimides (details).

     

    Laboratory apparatus for the accurate, facile and rapid determination of visible light photoreaction quantum yields (details).

     
    all 11 Publications


    mailto: webmaster
    Letzte Änderung:Letzte Änderung: 1970-01-01 01:00