0000000001059416

AUTHOR

P. H. Hynninen

showing 2 related works from this author

Circular and linear dichroism of aggregates of chlorophyll a and chlorophyll b in 3-methylpentane and paraffin oil.

1996

A circular (CD) and linear dichroism (LD) study of the water adducts of the green plant chlorophylls a (Chl a) and b (Chl b) in hydrocarbon solvents 3-methylpentane and paraffin oil is presented. A strong red shift of the Qy-absorption band from 663 to 746 nm (1678 cm−1) is observed as the water adduct of Chl a is formed. The Chl a-water adduct shows a strong, nonconservative CD signal, which is characterized by a positive peak at 748 nm and two negative peaks at 720 and 771 nm. The maximum CD (AL - AR) is only one order of magnitude smaller than the isotropic absorption maximum. We propose that this exceptionally strong signal is the so-called psi-type CD. The LD spectrum was measured in a…

Chlorophyll bChlorophyll a010304 chemical physicsChemistryAnalytical chemistryfood and beveragesmacromolecular substancesGeneral Medicine010402 general chemistryPhotochemistryLinear dichroism01 natural sciencesBiochemistry0104 chemical sciencesAdductRed shiftchemistry.chemical_compoundAbsorption band0103 physical sciencespolycyclic compoundsPhysical and Theoretical ChemistryAbsorption (chemistry)3-MethylpentanePhotochemistry and Photobiology
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CHLOROPHYLL a AGGREGATES IN HYDROCARBON SOLUTION, A PICOSECOND SPECTROSCOPY AND MOLECULAR MODELING STUDY

1993

Chlorophyll a aggregates in 3-methylpentane solution have been studied by using picosecond absorption and fluorescence spectroscopy and molecular modeling. Chlorophyll a aggregates give rise to reversible temperature changes in the absorption and fluorescence spectra. Time-dependent anisotropies were used to estimate rotational correlation times of the aggregates. These were indicative of the sizes of the aggregates. The rotational diffusion of the monomer and the two identified aggregates was hydrodynamic over the viscosity range studied (0.29–1.8 cP). Molecular mechanics calculations were used to predict the minimum energy structures of several chlorophyll a dimers suggested earlier in th…

Chlorophyll a010304 chemical physicsExcitonRotational diffusionGeneral Medicine010402 general chemistryPhotochemistry01 natural sciencesBiochemistryFluorescence spectroscopy0104 chemical scienceschemistry.chemical_compoundViscositychemistryChemical physicsPicosecond0103 physical sciencesPhysical and Theoretical ChemistryAbsorption (electromagnetic radiation)SpectroscopyPhotochemistry and Photobiology
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