1997 Fiscal Year Final Research Report Summary
The Study on Molecular Motions of Molecular Substances
| Project/Area Number |
08640632
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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 | Fukushima University |
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Principal Investigator |
HASEBE Tooru Fukushima University, Faculty of Education Professor, 教育学部, 教授 (10091852)
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| Project Period (FY) |
1996 – 1997
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| Keywords | nuclear maganetic resonance / relaxation time / diffusion coefficient / molecular motion / molecular motion in pores / molecular substances |
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| Research Abstract |
Phase transition is very attrctive subject for studying molecular motions in a liquid and a solid state. Particularly it is important to study of an initial state of the molecular motion and to relate it to the phase transition. The purpose of this study is to get an information of molecular motion in a liquid and a solid state of molecular substances, e.g. (CH_3) _4Si, (CH_3)_3CCI and other 11 molecular substances.
Self-diffusion coefficients and ^1H-NMR spin-lattice relaxation times were observed in wide temperature range (from the melting point to the boiling point at 1 atm) for these molecular substances. Furthermore the self-diffusion coefficient was observed for constrained samples of (CH_3)_3Si, (CH_3)_4Si, (CH_3) _3CCI and C_6, which were adsorbed in porous silica (pore sizes are of 6,9 and 10 nm i.d.).
In bulk liquid samples of these substances, the silf-diffusion coefficient shows a logarithmic dependence on an inverse temperature for all samples. The temperature dependence gave us the activation energy and the pre-exponential factor for the self-diffusional motion. It is interesting that the pre-exponential factor is closing to the self-diffusion coefficient of the supercritical gaseous state. It is furthermore interesting that the time scale of the self-diffusional motion in liquid state is not depend on molecular motions (overall molecular tumbling or self-diffusion) which are already excited in solid state. On the other hand, self-diffusion of the constrained sample is larger by a factor of 10 than that of the bulk sample. However the value of the activation energy for the motion in the porous silica is coincide with the value of the bulk sample within an experimental error. It seems that a molecular electric dipole moment is not responsible for these facts mentioned above.
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Research Products
(2 results)
