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Replacement of the central Mg in chlorophylls by Ni opens an ultrafast (tens of femtoseconds time range) radiationless de-excitation path, while the principal ground-state absorption and coordination properties of the pigment are retained. A method has been developed for substituting the native bacteriochlorophyll a by Ni-bacteriochlorophyll a ([Ni]-BChl)(More)
We investigated the dependence on solvents of optical absorption and emission of the bacteriochlorophyll a-serine (BChl-ser), a water soluble bacteriochlorophyll (BChl) derivative. Comparison between the experimental data and those collected for BChl in nonaqueous solvents shows that only a minor interaction takes place between serine and the macrocycle's(More)
The excited-state and lasing properties of 20-chloro-chlorophyll a in ether solution were compared to those of chlorophyll a. Desactivation parameters and cross-sections were obtained from non-linear absorption spectroscopy in combination with a phys-ice-mathematical methods package. The Cl substituent at C-20 (I) increases both intersystem crossing and(More)
By means of fluorescence spectroscopy and nonlinear absorption experiments, excited-state processes of the modified pigments [3-acetyl]-chlorophylla, [3 1-OH]-bacteriochlorophyl! a and [3-vinyl]-bacteriochlorophyll a were investigated and compared with those of chlorophyll a and bacteriochlorophyll a. I. Introduction because the structural differences(More)
Conventional linear and time-resolved spectroscopic techniques are often not appropriate to elucidate specific pigment–pigment interactions in light-harvesting pigment-protein complexes (LHCs). Nonlinear (laser-) spectroscopic techniques, including nonlinear polarization spectroscopy in the frequency domain (NLPF) as well as step-wise (resonant) and(More)
Zur Erlangung des akademischen Grades d o c t o r r e r u m n a t u r a l i u m 'Der vollkommene Weltmann wäre der, welcher nie in Unschlüssigkeit stockte und nie in Übereilung geriete.' Preface The thesis on hand was realized in the framework of two successive research projects (Ho 1757/2-1 and Ho 1757/2-2) financed by the DFG. Both projects extended a(More)
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