"Excited-state dynamics of bacteriorhodopsin probed by broadband femtosecond fluorescence spectroscopy"B. Schmidt, C. Sobotta, B. Heinz, S. Laimgruber, M. Braun, P. Gilch
Biochimica et Biophysica Acta 1706 (2005) 165-173
The impact of varying excitation densities (~0.3 to ~40 photons per molecule) on the ultrafast fluorescence dynamics of bacteriorhodopsin has been studied in a wide spectral range (630–900 nm). For low excitation densities, the fluorescence dynamics can be approximated biexponentially with time constants of ~0.15 and ~0.45 ps. The spectrum associated with the fastest time constant peaks at 650 nm, while the 0.45 ps component is most prominent at 750 nm. Superimposed on these kinetics is a shift of the fluorescence maximum with time (dynamic Stokes shift). Higher excitation densities alter the time constants and their amplitudes. These changes are assigned to multi-photon absorptions.
BMO authors (in alphabetic order):
Spectroscopy of the functional dynamics of proteins
Ultrafast Fluorescence Spectroscopy - The Kerr-Gate Setup