[Effect of the spectral composition of light on the mechanism of reaction of chlorophyll oxidation].
Photochemical oxidation of chlorophyll "a" on excitation of the pigment in different spectrum region (400-800 nm) was studied by flash photolysis. The absorption spectrum of chlorophyll cation-radical Chl+ was obtained and the values of extinction coefficient found. An attempt was made of photochemical generation of dication form of chlorophyll. Thermodynamical calculation supporting the possibility of the following reaction is presented: (Chl+)*+Ae -- Chl2""Ae. The absence of Chl2+ is explained by a short life time of the excited cation-radical of chlorophyll (Chl+)*. The effect of the wave length of excited light on the kinetics of the decay of chlorophyll cation-radical is studied. It is shown that on excitation of chlorophyll "a" with white light the life time of Chl+ decreases and its death is described by an equation of first order, which is explained by the formation of ion-radical of the electron acceptor resulting from the direct excitation of Ae.
D002734:Chlorophyll; D010084:Oxidation-Reduction; D010777:Photochemistry
D002734:Chlorophyll
Vliianie spektral'nogo sostava sveta na mekhanizm reaktsii okisleniia khlorofilla