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首页> 外文期刊>Physical review >Comparison of transient grating signals from spheroidene in an organic solvent and in pigment-protein complexes from Rhodobacter sphaeroides 2.4.1
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Comparison of transient grating signals from spheroidene in an organic solvent and in pigment-protein complexes from Rhodobacter sphaeroides 2.4.1

机译:来自球形溶剂在有机溶剂中和来自球形红球菌2.4.1的色素-蛋白质复合物中的瞬态光栅信号的比较

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摘要

The concurrent dynamics of the electronic excitation and vibronic oscillations of spheroidene have been investigated by means of the transient grating (TG) spectroscopy. The third-order optical responses of spheroidene in an organic solvent, in the LH2 light-harvesting antenna complexes, and in chromatophores have been compared in order to investigate the influence of the environment surrounding this photosynthetic pigment. Vibronic coherent oscillations with a period of several tens of femtosecond have been clearly observed superimposed on a slowly varying background, which reflects the electronic dynamics. The dynamics of the coherent oscillations have been analyzed by means of the wavelet analysis. Within our experimental accuracy, the decay times of the C=C and C-C stretching modes and C-CH_3 rocking mode of each specimen are very close. The experimental results have also been analyzed using a Brownian oscillator model. For these numerical calculations, the spectral density for the underdamped modes has been determined from the Raman spectrum of spheroidene. It was found that the low-frequency modes that reflect the influence of the protein environment can be approximated by the overdamped Brownian oscillator. The experimentally observed linear absorption spectra as well as the third-order optical responses, i.e., TG curves, are reproduced very well by these calculations. The close agreement between the experiments and calculations indicates that the Feynman-diagrammatic approach can be applied to express not only the internal conversion but also the intermolecular excitation energy-transfer processes. The vibronic decay rates of spheroidene in LH2 complexes and chromatophores are evaluated to be about 20% larger than in the organic solvent.
机译:通过瞬态光栅(TG)光谱研究了椭球的电子激发和振动的同时动力学。为了研究这种光合色素周围环境的影响,对有机溶剂,LH2捕光天线络合物和色谱中的球蛋白的三阶光学响应进行了比较。已经清楚地观察到几十飞秒周期的振动相干振荡叠加在缓慢变化的背景上,这反映了电子动力学。相干振荡的动力学已经通过小波分析进行了分析。在我们的实验精度范围内,每个样本的C = C和C-C拉伸模式以及C-CH_3摇摆模式的衰减时间非常接近。还使用布朗振荡器模型分析了实验结果。对于这些数值计算,欠阻尼模的光谱密度是根据椭球的拉曼光谱确定的。已经发现,反映蛋白质环境影响的低频模式可以通过过度阻尼的布朗振荡器来近似。通过这些计算,可以很好地再现实验观察到的线性吸收光谱以及三阶光学响应,即TG曲线。实验和计算之间的密切一致性表明,费曼图解法不仅可以用于表达内部转换,而且可以表达分子间激发能转移过程。据估计,LH2络合物和色谱中的椭球的振动衰减率比有机溶剂中大。

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  • 来源
    《Physical review》 |2010年第24期|P.245112.1-245112.10|共10页
  • 作者单位

    CREST-JST and Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585, Japan;

    rnCREST-JST and Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585, Japan;

    rnCREST-JST and Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585, Japan;

    rnCREST-JST and Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585, Japan;

    rnCREST-JST and Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585, Japan CREST-JST and Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555, Japan;

    rnDivision of Biochemistry and Molecular Biology, IBLS, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom;

    rnCREST-JST and Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585, Japan;

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  • 正文语种 eng
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  • 关键词

    coherent spectroscopy of atoms and molecules; ultrafast processes; optical pulse generation and pulse compression; theory, models, and numerical simulation;

    机译:原子和分子的相干光谱;超快过程;光脉冲产生和脉冲压缩;理论;模型和数值模拟;

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