【作者】 胡勇军； 李卫星； 肖卫战； 刘付轶； 盛六四；

【Author】 aYongjun Hu;aWeixin Li;aWeizhan Xiao;bFuyi Liu;bLiusi Sheng;College of Biophotonics, South China Normal University;National Synchrotron Radiation Laboratory, University of Science and Technology of China;

【机构】 华南师范大学生物光子学研究院； 中国科技大学同步辐射实验室；

【摘要】 光作用于生物体有多种效应,生物光化效应涉及到分子化学键的断裂和新键的形成。研究气相中生物分子电离解离过程是在分子水平上了解光化效应的重要途径。应用可调谐的同步辐射真空紫外光源和相关设备,我们对乙醇,乙酸等生物相关分子及其在超音速膨胀过程中形成的氢键团簇进行单光子电离,并应用飞行时间质谱探测。通过采集各个物种的光电离效率谱(PIE),并结合量化计算,探讨了这类分子及其团簇在真空紫外单光子电离过程中发生的分子-离子反应和多个解离反应通道。结果发现:乙酸二聚体离子存在有六种能量相近的分子构型,二聚体解离过程中发生的C-C键断裂与多构型的离子二聚体相关;在对乙醇二聚体进行研究的过程中,光子能量不同,二聚体中发生电离的部位可能也不同;同时还发现分子内的超共轭效应可能影响了乙醇分子的最优解离通道。最后我们还进一步探讨了在高能量光子辐射下,乙醇二聚体离子在解离过程中发生的甲基转移动力学过程。更多还原

【Abstract】 Study of the molecular photoionization and fragmentation in the gas phase is an important way at a molecular level to understand some biological effects such as actinic effect of laser. In the present report,we have studied the photoionization and fragmentation reaction dynamics of the jet cooled biological related molecules and its clusters by the use of VUV synchrotron radiation time of flight mass spectrometry. We found: 1) the cleavage of C-C in the acetic acid dimer is related to the multi-conformers; 2) site-selected ionization occurred in the photoionization of ethanol dimer under different VUV photon energies. 3) hyperconjugative effects could act some roles in the dissociative photoionization processes of the ethanol 4) migration of methyl has been observed in the photoionization and fragmentation under the higher photon energies radiation. Those results provide a clear picture of the photoionization and dissociation processes of small organic molecules and its clusters under the VUV synchrotron radiations.更多还原