title: [Spectral-kinetic characteristics of the cation-radical of pheophytin a].
abstract: The photochemical generation of pheophytin a cation-radical in acidulated ethanol and aceto nitril has been studied by the method of flash-photolysis. The bands with maxima at 450, 580 and 800 nm correspond to pheophytin a cation-radical in the differential absorption spectra. The efficient rate constants of pheophytin a triplet state desactivation in ethanol, acetonitril, aceton have the following values: 1.5.10(4), 9.10(3), 8.7.10(3) sec(-1) correspondingly. The rate constant of electron transfer from pheophytin a to p-benzoqui-none in ethanol solutions is 7.8.10(9) l/m.sec. The recombination constants of pheophytin a cation-radical with Q-in acetonitril, and with quinone neutral (QH) in acidulated ethanol have the following values: 5.10(9) and 2.10(9) l/m.sec correspondingly.
mesh_terms: D002734:Chlorophyll / Q000031:analogs & derivatives; D004578:Electron Spin Resonance Spectroscopy; D007700:Kinetics; D010674:Pheophytins; D010782:Photolysis; D011809:Quinones; D013057:Spectrum Analysis; D013696:Temperature
chemical_list: D010674:Pheophytins; D011809:Quinones; D002734:Chlorophyll
vernacular_title: Spektral'no-kineticheskie kharakteristiki kation-radikala feofitina a.