1999 Fiscal Year Final Research Report Summary
Uilta high resolution spectroscopy of excitons in quantum crystal
| Project/Area Number |
09304040
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
固体物性Ⅱ(磁性・金属・低温)
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
MOMOSE Takamasa Associate Professor, Department of Chemistry, Graduate School of Science, Kyoto University, 大学院・理学研究科, 助教授 (10200354)
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| Co-Investigator(Kenkyū-buntansha) |
WAKABAYASHI Tomonari Assistant, Department of Chemistry, Graduate School of Science, Kyoto University, 大学院・理学研究科, 助手 (30273428)
SHIDA Tadamasa Professor Emeritus, Department of Chemistry, Graduate School of Science, Kyoto University, 大学院・理学研究科, 名誉教授 (60025484)
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| Project Period (FY) |
1997 – 1999
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| Keywords | solid hydrogen / quantum crystal / laser spectroscopy / infrared spectroscopy / high-resolution spectroscopy / radiation / molecular ion / Stark spectroscopy |
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| Research Abstract |
A crystal of parahydrogen, in which nearly all the molecules are in the J=0 rotational state, is known as a quantum crystal. An exceptional feature of the crystal is its narrow spectral linewidth. Here, we have studied parahydrogen molecule itself and molecules embedded in parahydrogen crystal by high-resolution spectropscopy. From the analysis of fine structures, frequency shifts and spectral lineshape of the rotation-vinbration transitions, we have investigated specific nature of excitons and its relaxation dynamics in the quantum crystal. Some of the results are summarized as follows. (1) The first overtone vibrational transition of parahydrogen has been studied by high-resoultion laser spectroscopy. The fine spliting was interpreted as due to vibron hopping in the quantum crystal. Also, the quantum effect on the vibron could be discussed.(2) Temperature dependence on the linewdith of methane embedded in parahydrogen reveals that pure dephasing is predominant as the cause of the relaxation at low temperatures, but the dependence was completely different from those in classical solids. Moreover the polulation relaxation was found to strongly depend on the shape of vibrational modes.(3) Infrared absorption of gamma-ray irradiated parahydrogen has been studied. Infrared absorption of hydrogen molecules induced by ions produced by the irradiation was analyzed quantitatively. We have developed a new method to detect ions selectively by applying external electric field to the crystal.
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