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Photo-fragmentation of atomic clusters with TOF mass spectrometer

使用 TOF 质谱仪进行原子团簇的光断裂

基本信息

批准号：
09450085
负责人：
MARUYAMA Shigeo
金额：
$ 9.09万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09450085/
关键词：
Mass spectrum Atomic Cluster Photo-fragmentation Time-of-flight 原子クラスター

项目摘要

By improving the laser-vaporization supersonic-expansion cluster beam source, generated cluster ions were introduced into the TOF mass spectrometer and FT-ICR mass spectrometer. Relatively large silicon clusters (SiィイD210ィエD2 ? SiィイD230ィエD2) were generated and tested with both mass spectrometers. The photo-fragmentation experiments and chemical reaction experiments were performed. The reaction experiments with ethylene and nitric oxide showed an interesting contrast. Ethylene molecules simply attached to Si clusters, while nitric oxides extracted a silicon atom as SiO from silicon clusters. In addition to these experimental studies, simple molecular dynamics simulations were performed to clarify the photo-dissociation mechanism of silicon clusters.Metal-carbon binary clusters were studied for the understandings of formation mechanism of single-walled carbon nanotubes and metal-including fullerenes. Through chemical reaction experiments with FT-ICR apparatus, some geometrical information of La-carbon and Ni-carbon clusters were obtained. The La-carbon clusters had the closed caged structure even for small size as La@CィイD244ィエD2. These clusters were much less reactive to NO compared with bare carbon clusters. On the other hand, Ni atom seemed to attach to the carbon clusters. The clusters with a Ni atom readily reacted with NO. Along with these experimental works, classical molecular dynamics simulations were performed for the clustering process from carbon and metal atoms. The classical potential functions between metal atoms (Ni, Sc, La) and a carbon atom were estimated from the DFT calculations of small clusters. The predicted structures of La-carbon clusters and Ni-carbon clusters could qualitatively explain the chemical reaction experiments.

通过改进激光汽化超音速膨胀团簇束源，将生成的团簇离子引入到TOF质谱仪和FT-ICR质谱仪中。相对较大的硅团簇(Si φ 210 φ D2 ？生成Si γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ。进行了光破碎实验和化学反应实验。乙烯和一氧化氮的反应实验显示了一个有趣的对比。乙烯分子简单地附着在硅簇上，而一氧化氮从硅簇中提取一个硅原子作为SiO。除了这些实验研究外，还进行了简单的分子动力学模拟来阐明硅团簇的光解离机制。研究了金属-碳二元簇，以了解单壁碳纳米管和含金属富勒烯的形成机理。通过FT-ICR装置的化学反应实验，得到了la -碳和ni -碳簇的一些几何信息。la -碳簇即使在小尺寸（La@C D244 D2）下也具有封闭笼状结构。与裸碳团簇相比，这些团簇对NO的反应性要小得多。另一方面，Ni原子似乎附着在碳簇上。带有Ni原子的团簇容易与NO发生反应。在此基础上，对碳原子和金属原子的聚类过程进行了经典的分子动力学模拟。通过小簇的DFT计算，估计了金属原子（Ni, Sc, La）与碳原子之间的经典势函数。预测的la -碳团簇和ni -碳团簇结构可以定性地解释化学反应实验。