Laser spectroscopic study of formation of alkali-earth and He van der Waals molecules
| Project/Area Number |
17550008
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Physical chemistry
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| Research Institution | University of Toyama |
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Principal Investigator |
MORIWAKI Yoshiki University of Toyama, Department of Physics, Associate Professor (90270470)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUSHIMA Fusakazu Toyama University, Professor (40142236)
KOBAYASHI Kaori Toyama University, Assistant Professor (80397166)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2006: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2005: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Laser spectroscopy / exciplex / van der Waals molecules / Atomspectroscopv / Alkari earth atoms / ヘリウム / 超流動ヘリウム / エキサイプレッタス / 原子分光 |
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| Research Abstract |
1. Spectroscopic study of alkali-earth atom - He collision dynamics in low temperature
(1) Formation of Mg^<*4>He_n exciplex in low temperature
We have observed the formation of ^<*4>MgHe_n exciplexes by means of laser excitation of Mg into the 3s3p ^1P_1 state in low temperature He gas (5-30K). Emission spectra have been analyzed using a theoretical pair potential. Exciplexes grow in many three-body reactions within its lifetime in the electronic excited state. Finally up to ten He atoms are attached around to a Mg atom to form a Mg*He_<10>. We have also observed almost the same results for Mg_<-3>He collisions. In this research, we have shown that the Mg*Hen molecules are formed although attractive interaction energy between Mg and He is small.
(2) Collision dynamics of Ba^<+>-He
We have investigated the relaxation process of Ba+ in the 6p ^2P_<3/2> state in collision with He atoms using laser spectroscopic method. We have obtained the rate constants of the formation and dissociation of Ba+*He, and the fine structure changing collision of Ba+ and Ba+*He. The resonance like structure observed in the cross section of the formation of Ba+*He exciplex indicates the two-step Lindemann mechanism. We have also observed a peculiar increase in the cross section of the fine-structure changing collision at the low temperature. This indicates another channel of the fine-structure change opens in the low temperature.
2. Fine-structure changing collision of alkali-earth ion
We have measured the fine-structure changing collision cross sections of alkali-earth ions at room temperature in collision with He, H_2 and D_2. We have found that cross sections for collisions with He atoms decrease exponentially with the fine-structure splitting, which can be explained by the Landau-Zener model of the adiabatic transition. In contrast to this, cross sections for hydrogen molecules are much enlarged due to resonance between the fine-structure splitting and the rotation of hydrogen molecule.
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Report
(3 results)
Research Products
(14 results)
