High Resolved Low Temperature Spectroscopy of Photosynthetic Systems

Site selection and hole burning spectroscopy are low temperature spectroscopic techniques based on the removal of the inhomogeneous broadening in optical spectra. These spectroscopic techniques, applied to photosynthetic systems, their subunits and models, represent powerful tools for studying pigment-pigment and pigment-matrix interactions, as well as energy transfer and electron transport. The digested information obtained from low temperature spectroscopy results on chlorophylls and photosynthetic systems can be found in |1|. Most important results are briefly mentioned below. Conventional low temperature spectra of chlorophylls in vitro have shown only broad bands in absorption and emission. The narrow red laser excitation enables to observe vibrationally resolved site selection spectra in solid solutions |2, 3| and in polymer foils |4|. The hole burning (HB) effects in absorption (A) and fluorescence excitation (E) spectra were measured in different matrices including the discussion of HB mechanisms |5, 6, 7|.