| 若干氢键团簇的纳秒和飞秒激光光电离及从头计算研究(英文) |
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| 作者姓名： | 张柏林 楼南泉 王秀岩 |
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| 作者单位： | 中国科学院大连化学物理研究所分子反应动力学国家重点实验室, 大连 116023 |
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| 摘 要： | 利用纳秒和飞秒激光及飞行时间质谱仪对氮化苯-溶剂分子团簇的多光子电离和离解进行了研究.通过解决实验中的技术难题,实现了在气相条件下实验研究嘧啶与水团簇的多光子电离.首次观测到该团簇的多光子电离质谱,发现电离后形成了质子化团簇系列,通过团簇浓度随激光强度的变化以及理论计算,阐明了团簇内质子转移过程,以及电荷分布和质子转移过程随着团簇尺寸的变化;首次观测到吡啶团簇在飞秒光电离过程中的质子化和非质子化团簇离子共存的现象.非质子化吡啶二聚体离子的存在及高水平下理论计算表明,吡啶分子之间可以形成C-H…N氢键,对文献中报道的结果给予了纠正,提供了弱氢键团簇中质子转移的一个极佳范例;首次研究并获得了嘧啶-甲醇以及哒嗪-甲醇氢键团簇的多光子实验研究结果.实验发现团簇经激光电离后只产生质子化产物,并从理论计算得到各种团簇的稳定构型,阐明了团簇发生电离后质子转移反应的过程和机理.
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| 关 键 词： | 氢键团簇 多光子电离 从头计算 |
| 收稿时间： | 2002-12-18 |
Nanosecond and Femtosecond Laser Photoionization and Ab Initio Calculation Studies of Some Hydrogen Bonded Clusters |
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| Authors: | ZHANG Bai-Lin LOU Nan-Quan WANG Xiu-Yan |
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| Institution: | State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Dalian 116023, China |
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| Abstract: | The multiphoton ionization and dissociation of azabenzenes-solvent clusters were studied using a time-of-flight mass spectrometer, nano- and femtosecond lasers. Due to the fact that the problem was resolved technically, the experiments about multiphoton ionization of pyrimidine-water in gas phase were performed successfully. The multiphoton ionization mass spectroscopy of the clusters was observed for the first time. The experimental results indicate sequences of protonated cluster ions are formed. Based on both ab initio calculations results and dependence of cluster ion intensity on the laser power, the processes of proton transfer and charge transfer within the clusters were presented. During the femtosecond laser photonionization of pyridine clusters, the coexistencephenomena of protonated and unprotonated cluster ions was observed first. The existence of pyridine dimmer ions and relevant calculation results indicate that the C-H...Nbonds can be formed between pyridine molecules, which corrected some reported results and also provided with a good example for the study of weak bond clusters. The multiphoton ionization results of pyrimidine-methanol and pyridazine-methanol clusters are presented for the first time. It is also found that only the protonated cluster ions are produced after clusters' ionization. The stable structures of all clusters were obtained theoretically, and the mechanisms and processes of proton transfer after ionization were elucidated. |
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| Keywords: | hydrogen-bonded clusters multiphoton ionization ab initio calculation |
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