| The dissertation, "the study of photosynthesis mechanism of higher plants and electronic structure properties of clusters", has two parts. The main part, "ultrafast dynamic study on energy transfer in Photosystem II of photosynthesis", is the sub-subject of "photosynthesis high efficiency light energy transfer mechanism and its application in agriculture" which is a key basic research and development plan, has been studied by ultrafast spectroscopy in State Key Laboratory of Transience Optics Technology Xi'an Institute of Optics and Academy of Sciences. The second part, "Theoretical investigation on the electronic properties of semiconductor clusters", is the study with regard to the work of Institute of Laboratory Optics Technology and Photonitics where I study for my diploma of Ph. D.The key contents of the topic on the main part are follows:1. The information concerning: the signification of the study on photosynthesis, the study process of primary reactions, biological structure its function of PSII, the development of ultsashort pulse laser and ultrafast spectroscopy techniques and their application in Physics, Chemistry and Biology is summarized in detail. The mechanism of light harvest, transfer and trap and electron transfer process in PSII was discussed.2.The methods of data processing in measurement of time-resolved spectra have been analyzed. Small wave analysis was first used in debasing noise. Computer software of data processing with the function of nonlinear least-square deconvolution is developed.3. A setup of femtosecond time-resolved fluorescence spectroscopy is established with Tiisapphire femtosecond laser bumped by Ar+ laser, frequency double, monochromatic, photoelectric multiplier tube and boxcar as its major components.4.Fluorescence spectroscopic and time property of light-harvesting complex (LHCII) and core complex, which was isolated from spinach inphotosystem II was investigated using the setup mentioned in number 3. Theconclusions were drawn from tijie analysis experiment results: l).In LHC II,three lifetime components (326 fs.4.0 DS and 20.0 ns) were detftr.te.H bv multi-exponential curve fitting method. The fluorescence ratio of each component to whole component) is 3.4%, 50% and 46.6%, respectively. The figure of the light absorbed ana transferred has been drawn according to the structural and fluorescence spectroscopy property of LHC II. 2). In core complex, three lifetime components were detected by multi-exponential and non-linear least square curve fitting. Those components are 3.9 DS, 20.4 DS and 930.5 DS. The fluorescence pigments ratio of each component to the whole is 1.0%, 12.7% and 86.3%, respectively. The figure of the light absorbed and transferred has been drawn according to the structural and fluorescence spectroscopy property of core complex, also.5.A novel method of Picosecond-resolving fluorescence spectrum measurement with delay-frame-scanning single photon counting technique was introduced. This spectrum setup was made innovatively. The time resolving Dower was improved 16.7 times by delay-frame-scanning technique. The advantage of avalanche photoelectric detector (APD) with rapid response was exerted mostly. It also has high property of signal-to-noise ration and sensitivity (5 pw light could response).6.The setup, which is mentioned in number 5, has been used in studying the sample of core complex, core antenna CP43, CP47, CP47&RC that was isolated from spinach in photosystem II. Those samples were treated in hot water 5 minutes with temperature at 20?C, 42?C and 48?C, respectively before the measurement. Comparing the data we got from the every sample experiment in different temperature, the conclusions were that: 1). The rates of the enerev transferred are varied at different wavelength. 2). The. rate of theenergy transferred becoming slower with the wavelength bigger. 3). Some special evidence at 42?C have been found especially CP47, it might have been a critical temperament which the protein complex were disass...
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