The vibrational energy transfer from highly vibrationally excited CO to H 2O molecules is studied by time-resolved Fourier transform infrared emission spectroscopy (TR FTIR). Following the 193 nm laser photolysis of C...The vibrational energy transfer from highly vibrationally excited CO to H 2O molecules is studied by time-resolved Fourier transform infrared emission spectroscopy (TR FTIR). Following the 193 nm laser photolysis of CHBr 3 and O 2 the secondary reactions generate CO(v). The infrared emission of CO(v→v-1) is detected by TR FTIR. The excitation of H 2O molecules is not observed. By the method of the spectral simulation and the differential technique, 8 rate constants for CO(v)/H 2O system are obtained: (1.7±0.1), (3.4±0.2), (6.2±0.4), (8.0±1.0), (9.0±2.0), (12±3), (16±4) and (18±7) (10 -13cm 3·molecule -1·s -1). At least two reasons lead to the efficient energy transfer. One is the contributions of the rotational energy to the vibational energy defect and the other is the result of the complex collision. With the SSH and ab initio calculations, the quenching mechanism of CO(v) by H 2O is suggested.展开更多
The mechanisms of excitation energy transfer within allophycocyanin monomer with the theory of generalized master equation (GME) and the technique of time-resolved fluorescence anisotropic spectroscopy are studied. In...The mechanisms of excitation energy transfer within allophycocyanin monomer with the theory of generalized master equation (GME) and the technique of time-resolved fluorescence anisotropic spectroscopy are studied. In the case of known information of its structure and spectra, the theory applied is based on the assumption that the coupling interaction between two chromophores is fairly weak. The theory correctly predicts the experimentlly observed rate for excitation energy transfer in allophycocyanin monomer. Based on the results, the energy transfer mechanism can be described as Frster and these processes cannot take place from the high vibrational levels of donor to acceptor.展开更多
Excitation energy transfer processes and mechanism in C-PC hexamer have been studied in detail by picosecond time-resolved fluorescencs isotropic and anisotropic spectroscopy methods. The experimental results show tha...Excitation energy transfer processes and mechanism in C-PC hexamer have been studied in detail by picosecond time-resolved fluorescencs isotropic and anisotropic spectroscopy methods. The experimental results show that there are two types of principal channels, with large probability or amplitude, for linking two trimers viam?m and s?s energy transfer pathways, the energy-transfer time constants of them are about 20 and 10 ps, respectively. Indeed, there exists the evidence for energy-transfer channels of s?f steps in the same monomer and threef?f steps in the same trimer of the C-PC hexamer unit, with small probability or amplitude, and the time constants of them might be ca. 50 and 45 ps separately. Also, the present results show that the hexamer possesses an optimal structure for energy-transfer and for the first time confirm that the dominant energy-transfer processes except those between 1 m?2f, 2m?3f and 3m?1f and so on, in isolated C-PC hexamer, could be described by F?rster dipole-dipole resonance mechanism.展开更多
The conjugate of R-phycoerythrin (R-PE) and C-phycocyanin (C-PC) was synthesized through a heterobifunctional coupling reagent, N-succinimidyl 3-(2-pyridyldithio) propionate. The molar ratio of R-PE to C-PC was determ...The conjugate of R-phycoerythrin (R-PE) and C-phycocyanin (C-PC) was synthesized through a heterobifunctional coupling reagent, N-succinimidyl 3-(2-pyridyldithio) propionate. The molar ratio of R-PE to C-PC was determined by absorption spectra, and the result was 2:1. The energy transfer phenomena were observed from steady-state fluorescence spectra. The calculated result showed that the energy transfer efficiency from R-PE to C-PC was 88%. The energy transfer kinetics was determined by picosecond time-resolved fluorescence spectra. The time constant of energy transfer from R-PE to C-PC was 80 ps, which was much longer than that in the rood of native phycobilisomes.展开更多
Surface-plasmon（SP） modes triggered on metal nanostructures were strongly coupled to the local restricted electronmagnetic field supported by a Fabry-Perot（F-P） cavity. This hybrid system provided an ideal platfor...Surface-plasmon（SP） modes triggered on metal nanostructures were strongly coupled to the local restricted electronmagnetic field supported by a Fabry-Perot（F-P） cavity. This hybrid system provided an ideal platform to study the interaction between SP and F-P resonators on nanoscales. However, the time-resolved transient energy transfer process is far from resolved. In this letter, we addressed this question by time-resolved femtosecond pump-probe technology and readily observed the transient energy transfer between SP and nanocavity resonant ener- gy. The interaction resulted in the emergence of hybrid splitting mode and the oscillating dynamics between upper and lower polariton branch（the split hybrid states）. Our work may provide a well comprehension of strong coupling between SP modes and F-P resonator modes, and lay some groundwork for many future photonic applications.展开更多
IN a previous paper, we have studied the energy transfer mechanism among the PBS-thy-lakoid complex in detail by using steady-state spectra and deconvolution techniques. The ex-perimental results indicated that the en...IN a previous paper, we have studied the energy transfer mechanism among the PBS-thy-lakoid complex in detail by using steady-state spectra and deconvolution techniques. The ex-perimental results indicated that the energy transfer from PBS to two reaction centers of PS Ⅰand PS Ⅱ were parallel, and confirmed the model which was suggested by Mullineaxu.展开更多
Thylakoid membrane preparations of super high-yield hybrid rice (Oryza sativa L.), Liangyoupeijiu (P9) and Shanyou 63 (SH 63) were used for investigating its spectral and time properties by using picosecond time-resol...Thylakoid membrane preparations of super high-yield hybrid rice (Oryza sativa L.), Liangyoupeijiu (P9) and Shanyou 63 (SH 63) were used for investigating its spectral and time properties by using picosecond time-resolved fluorescence spectrum measuring system. The thylakoid membrane preparations of P9 and SH 63 were excited by an Ar+ laser with a pulse width of 120 ps, repetition rate of 4 MHz and wavelength of 514 nm. The time constants of the excited energy transfer in these two varieties at flowering stage and grain filling stage were calculated from the experimental data. Based on the comparative studies of the time and spectral properties of the excited fluorescence in these ultrafast dynamic experiments the following was found: at both the flowering stage and grain filling stage, the speed of the excitation energy transfer, in photosystem was faster than that in photosystem II in P9 variety; and the speed of the excitation energy transfer at grain filling stage was faster than those at flowering stage for both rice varieties; the experiments also implied that the components and assembly of pigments in SH 63, but not in P9, changed during the process from flowering stage to grain filling stage for in these two rice varieties.展开更多
文摘The vibrational energy transfer from highly vibrationally excited CO to H 2O molecules is studied by time-resolved Fourier transform infrared emission spectroscopy (TR FTIR). Following the 193 nm laser photolysis of CHBr 3 and O 2 the secondary reactions generate CO(v). The infrared emission of CO(v→v-1) is detected by TR FTIR. The excitation of H 2O molecules is not observed. By the method of the spectral simulation and the differential technique, 8 rate constants for CO(v)/H 2O system are obtained: (1.7±0.1), (3.4±0.2), (6.2±0.4), (8.0±1.0), (9.0±2.0), (12±3), (16±4) and (18±7) (10 -13cm 3·molecule -1·s -1). At least two reasons lead to the efficient energy transfer. One is the contributions of the rotational energy to the vibational energy defect and the other is the result of the complex collision. With the SSH and ab initio calculations, the quenching mechanism of CO(v) by H 2O is suggested.
文摘The mechanisms of excitation energy transfer within allophycocyanin monomer with the theory of generalized master equation (GME) and the technique of time-resolved fluorescence anisotropic spectroscopy are studied. In the case of known information of its structure and spectra, the theory applied is based on the assumption that the coupling interaction between two chromophores is fairly weak. The theory correctly predicts the experimentlly observed rate for excitation energy transfer in allophycocyanin monomer. Based on the results, the energy transfer mechanism can be described as Frster and these processes cannot take place from the high vibrational levels of donor to acceptor.
文摘Excitation energy transfer processes and mechanism in C-PC hexamer have been studied in detail by picosecond time-resolved fluorescencs isotropic and anisotropic spectroscopy methods. The experimental results show that there are two types of principal channels, with large probability or amplitude, for linking two trimers viam?m and s?s energy transfer pathways, the energy-transfer time constants of them are about 20 and 10 ps, respectively. Indeed, there exists the evidence for energy-transfer channels of s?f steps in the same monomer and threef?f steps in the same trimer of the C-PC hexamer unit, with small probability or amplitude, and the time constants of them might be ca. 50 and 45 ps separately. Also, the present results show that the hexamer possesses an optimal structure for energy-transfer and for the first time confirm that the dominant energy-transfer processes except those between 1 m?2f, 2m?3f and 3m?1f and so on, in isolated C-PC hexamer, could be described by F?rster dipole-dipole resonance mechanism.
文摘The conjugate of R-phycoerythrin (R-PE) and C-phycocyanin (C-PC) was synthesized through a heterobifunctional coupling reagent, N-succinimidyl 3-(2-pyridyldithio) propionate. The molar ratio of R-PE to C-PC was determined by absorption spectra, and the result was 2:1. The energy transfer phenomena were observed from steady-state fluorescence spectra. The calculated result showed that the energy transfer efficiency from R-PE to C-PC was 88%. The energy transfer kinetics was determined by picosecond time-resolved fluorescence spectra. The time constant of energy transfer from R-PE to C-PC was 80 ps, which was much longer than that in the rood of native phycobilisomes.
基金Supported by the National Basic Research Program of ChinafNos.2014CB921302, 2011CB013003）, the National Natural Science Foundation, of China（Nos.21273096, 61378053） and the Doctoral Fund of Ministry of Education of China（No.20130061110048）.
文摘Surface-plasmon（SP） modes triggered on metal nanostructures were strongly coupled to the local restricted electronmagnetic field supported by a Fabry-Perot（F-P） cavity. This hybrid system provided an ideal platform to study the interaction between SP and F-P resonators on nanoscales. However, the time-resolved transient energy transfer process is far from resolved. In this letter, we addressed this question by time-resolved femtosecond pump-probe technology and readily observed the transient energy transfer between SP and nanocavity resonant ener- gy. The interaction resulted in the emergence of hybrid splitting mode and the oscillating dynamics between upper and lower polariton branch（the split hybrid states）. Our work may provide a well comprehension of strong coupling between SP modes and F-P resonator modes, and lay some groundwork for many future photonic applications.
文摘IN a previous paper, we have studied the energy transfer mechanism among the PBS-thy-lakoid complex in detail by using steady-state spectra and deconvolution techniques. The ex-perimental results indicated that the energy transfer from PBS to two reaction centers of PS Ⅰand PS Ⅱ were parallel, and confirmed the model which was suggested by Mullineaxu.
文摘Thylakoid membrane preparations of super high-yield hybrid rice (Oryza sativa L.), Liangyoupeijiu (P9) and Shanyou 63 (SH 63) were used for investigating its spectral and time properties by using picosecond time-resolved fluorescence spectrum measuring system. The thylakoid membrane preparations of P9 and SH 63 were excited by an Ar+ laser with a pulse width of 120 ps, repetition rate of 4 MHz and wavelength of 514 nm. The time constants of the excited energy transfer in these two varieties at flowering stage and grain filling stage were calculated from the experimental data. Based on the comparative studies of the time and spectral properties of the excited fluorescence in these ultrafast dynamic experiments the following was found: at both the flowering stage and grain filling stage, the speed of the excitation energy transfer, in photosystem was faster than that in photosystem II in P9 variety; and the speed of the excitation energy transfer at grain filling stage was faster than those at flowering stage for both rice varieties; the experiments also implied that the components and assembly of pigments in SH 63, but not in P9, changed during the process from flowering stage to grain filling stage for in these two rice varieties.
