1999 Fiscal Year Final Research Report Summary
Photo-fragmentation of atomic clusters with TOF mass spectrometer
| Project/Area Number |
09450085
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Thermal engineering
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| Research Institution | The University of Tokyo |
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Principal Investigator |
MARUYAMA Shigeo Eng. Res. Inst., The University of Tokyo, Associate Professor, 工学部・附属総合試験所, 助教授 (90209700)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUMOTO Yoichiro School of Engineering, The University of Tokyo, Professor, 大学院・工学系研究科, 教授 (60111473)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Mass spectrum / Atomic Cluster / Photo-fragmentation / Time-of-flight |
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| Research Abstract |
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.
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