Study On Solvent Effect On Chlorophyll A Fluorescence Quenching

Chlorophyll a(chlorophyll a)is one of the indispensable basic substances in photosynthetic process.Photosynthesis converts light energy into biochemical energy,providing energy for life on earth.Photosynthesis is initiated by light capture,followed by a series of energy transfer through a very complex network of pigment-protein complexes,which produce electron transfer at the center of photosynthesis.These processes are closely related to chlorophyll a,which plays different roles in different functional structures.The absorption of chlorophyll a,fluorescence is in the visible range,which gives us the convenience of studying the structure of chlorophyll a.By studying the chlorophyll a absorption spectrum and fluorescence spectrum in different environment under the influence of the change,we can simulate the chlorophyll a spectral response in different living environments,and to understand the different structure of chlorophyll-a in the organic life played by different functions.Alpha-carotene is also one of the basic substances of photosynthesis.Linear polyene is a chain molecule that has electron conjugate double bonds.Its characteristics of large nonlinear coefficient and fast photoelectric response have important applications in the development of high quality semiconductor.At the same time,the beta carotene compared with chlorophyll a,have relatively loose chemical structure,is a kind of good quenching agent,to adjust the photosynthesis efficiency,light protection,and energy transfer and the expansion of organisms in photosynthesis light capture spectrum plays an important role.Therefore,by studying the electron states and vibrational properties of caeronium-carotene,we can obtain information of energy levels of caeronide.It is known that the dark state S1 is located at about 4000cm-1 below the S2 energy level,which satisfies the requirements of simple energy transfer mechanism.Therefore,by changing the solvent concentration,solvent polarity,etc.,to not cannot be observed in the steady state spectra of beta carotene S1 state modulation level position,resulting in energy transfer can be indirect characterization of S1 state characteristics of the spectral parameters.This paper applies Beer-Lambert's law,the Frank-Condon transition model,the effective length of conjugated model,coupled to the absorption spectrum and fluorescence spectrum technology,and combined with Raman spectrum,and measured the beta carotene in different concentration of chlorophyll a,absorption spectrum and fluorescence spectrum.The intensity,frequency shift and linear of the absorption spectra and fluorescence spectra of the quenching agent were studied,and the ster-volmer curve was made.By changing the solvent polarizability,beta-carotene,absorption spectrum redshift,and modulating the S1 level position,wisecarver k d factor,electron phonon coupling features,and observed at different concentration quenching agent's influence on the absorption spectrum and fluorescence spectrum.The following innovations have been achieved:1.The absorption and fluorescence spectra of chlorophyll a and beta-carotene were different in quenching efficiency under different polar solvents.The fluorescence intensity of chlorophyll a decreased with the increase of beta-carotene.The outer environment,such as temperature and solvent effect,regulates the off-domain expansion of carotenoid electrons.Changing the solvent polarity,the excited state energy level of beta-carotene is closer to the excited state energy level of chlorophyll a,leading to the occurrence of electron transfer.Electron transfer produces electron separation pairs(chl-chl +),which do not produce fluorescence,resulting in fluorescence quenching.The decrease of chl-a fluorescence can be observed by regulating the energy flow of photosynthesis through interaction with chlorophyll.2.Fluorescence red shift changes with the increase of solvent polarization rate.Solvent polarizability increases,beta-carotene,S2 state redshift,beta-carotene,effective conjugation length increases,the corresponding S1 state energy of a corresponding position will be modulation,which modulation energy transfer.In quenching,electron transfer should be the dominant position,and energy transfer also contributes.3.Solvents with high polarizability and polarity have high quenching efficiency.When soluble in carbon tetrachloride,chl-a presents red absorption transfer and blue shift of fluorescence spectrum,which is related to the structural changes of chlorophyll.