| Project/Area Number |
07454190
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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 |
機能・物性・材料
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| Research Institution | Okazaki National Research Institutes (1996-1997)
Kyushu University (1995) |
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Principal Investigator |
NISHI Nobuyuki OKAZAKI NATIONAL RESEARCH INSTITUTE,Institute for Molecular Science, Professor, 分子科学研究所, 教授 (60013538)
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| Co-Investigator(Kenkyū-buntansha) |
OHASHI Kazuhiko OKAZAKI NATIONAL RESEARCH INSTITUTE,Institute for Molecular Science, Research As, 分子科学研究所, 助手 (80213825)
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| Project Period (FY) |
1995 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥7,800,000 (Direct Cost: ¥7,800,000)
Fiscal Year 1997: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1996: ¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 1995: ¥4,000,000 (Direct Cost: ¥4,000,000)
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| Keywords | molecular ion clusters / matrix isolation / charge hopping / photodissociation / IR spectroscopy / benzene cation / 赤外分光 / 分子イオン / クラスター / ソフトランディング / 分子分光 |
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| Research Abstract |
In order to study electronic states and dynamics of highly condensed molecular ion clusters, we designed a molecular beam apparatus with a soft-landing ion deosition and IR and UVabsorption spectrometers. A molecular beam generated from liquid droplets by adiabatic Big-Bang explosion is directly injected against 10-inch diffusion pump. Ions are extracted perpendicular to the beam axis, mass-selected, decelerated, and gently imbedded in a rare gas matrix. As atest experiment, benzene cations are deposited in argon matrices at 4 K.Contamination of the background neutral benzene was so little that after 10 hour deposition we can detect the neutrals by UV absorption spectrometry. The electronic spectrum of benzene cation showed that the electronic orbitals of argon atoms around the cation is highly distorted and polarized by the cation. The high dnsity deposition process was accompanied with a big difficulty without any codeposition of negative ions. Frequent explosive ablation of the new surface layrs was observed during the deposition. It is necessary to design a natural negative ion deposition mechanism in a chamber.
We also observed a charge hopping phenomenon in benzene trimer cations after vibrational excitation of a C-H stretching motion of an ionic molecule. The excitation of an isotopic mixture (C_6H_6) ^+ (C_6D_6)_2 resulted in the fragmentation yielding (C_6D_6)_2^+ and [ (C_6D_6) (C_6H_6) ]^+ with a ratio of 1 : 2. This is a statistical limit suggesting the hopping occurs sufficiently faster than the dissociation process. The observed line-widths of the C-H stretching bands showed sectral shifts dependent on the position of the charged molecules in the cluster and also on the masses of the neighboring molecules. Rather broad line-widths indicates that the relaxation is of the order of 100-150fs.
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