Biosynthesis of chlorophyl studied by time-resolved Raman spectroscopy

本项目有两个目标：(1)通过皮秒到微秒时间分辨吸收光谱的详细研究，发现新的叶绿素生物合成过程的中间体，并从动力学研究中确定该过程的时间常数。(2)利用中间体的时间分辨共振拉曼光谱，有望确定中间体的结构。对于第一个目标，经过改进装置和重复实验，发现生物合成过程描述为：PChlide-650->PChlide(S_1)->^^^< PS>X-B ->^^^<<正负>0.2< <micrn>S>X-690 ->^^^<<正负>20<micrn>S>X-684 ->^^^<<正负>0.5<micrn>S> Chlide-678->^^ <5<正负>2.0<micrn>S>Chla。所有中间产物均与低温时一致。对于第二个目标，由于荧光非常强烈，新发现的中间体和其他中间体的时间分辨共振拉曼光谱很难观察到。在目前阶段，我们还没有成功地得到拉曼光谱。在非相干光法的基础上，利用宽带染料激光观测CARS或CSRS，建立了时间分辨拉曼光谱装置，用于测定飞秒振动相弛豫。将工作扩展到电子减相时间的测量，得到了许多科研人员的高度评价。首席研究员被邀请在国际会议上发言6次以上，受邀撰写论文3篇以上。

There were two targets of this project: (1)By detailed study of picosecond to microsecond time-resolved absorption spectroscopy, new intermediates in the biosynthetic processes of chlorophyl in the time region were to be discovered and from the dynamical study, the time constants of the processes were to be determined. (2)From the time-resolved resonance Raman spectra of the intermediates, the structure were expected to be determined.Concerning the first target, after improving the apparatus, and repeating the experiment the biosynthetic process was found to be described as:PChlide-650->PChlide(S_1)->^^^< PS>X-B ->^^^<<plus-minus>0.2<micrn>S>X-690 ->^^^<<plus-minus>20<micrn>S>X-684 ->^^^<<plus-minus>0.5<micrn>S> Chlide-678->^^^<5<plus-minus>2.0<micrn>S>Chla.All the intermesiates were found to be correspondent with those at low temperature.Concerning the second targer, it was very difficult to observe the timeresolved resonance Raman spectra of the newly found and other intermediates because of the very in tense fluorescence. At the present stage, we have not yet succeeded in getting the Raman spectra. However, the apparatus constructed for the time-resolved Raman spectra was used for the determination of femtosecond vibrational phase relaxation by observing CARS or CSRS using broad band dye laser on the basis of incoherent light method. The work was extendod to the electronic dephasing time measurement and these works were highly evaluated by many scientific research people. The head investigator was invited more than six times to give talks at the international conferences and was asked to write more than three invited papers.