2007 Fiscal Year Final Research Report Summary
Path integral simulation study of quantum dynamics of hydrogen doped inside carbon nanotubes
| Project/Area Number |
18550018
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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 | Nara Women's University |
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Principal Investigator |
KINUGAWA Kenichi Nara Women's University, Faculty of Science, Associate professor (50254446)
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| Project Period (FY) |
2006 – 2007
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| Keywords | nanotube-fullerene / new energy / hydrogen / simulation technology |
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| Research Abstract |
The centroid path integral molecular dynamics (CMD) simulations have been carried out for the systems of para-hydrogen contained inside the carbon nanotubes. For these simulations the CMD source program for numerical calculations has newly been developed. We have employed the isothermal-isobaric ensemble molecular dynamics technique to keep the pressure tensor along the z-direction constant and the temperature arising from all the degrees of freedom constant as well. The Andersen-type isobaric technique and the Nose-Hoover chain-type isothermal technique have been employed for this purpose. As for molecular interaction, the Silvera-Goldman potential and the Lennard-Jones potential have been assumed to be valid for the hydrogen-hydrogen and the hydrogen-carbon interaction, respectively. For the latter interaction, the nanotube inner wall has been smoothed out over the whole spatial range so that the nanotube wall should have flat and uniform surface without identification of carbon atoms. The CMD simulations for this model have been performed at the condition that the number of hydrogen molecules is 312, the temperature is 8-15 K, and Trotter number is 100. The anisotropy of dynamics has been clarified on the basis of the analysis of the mean square displacement and the velocity autocorrelation function of imaginary time path integral centroids of hydrogen molecules. Furthermore, it has been found that the hydrogen inside the nanotube tends to have higher melting temperature than the bulk system. As a reference of the nanotube hydrogen system, the physical properties of bulk hydrogen revealed by means of the CMD simulations have been reviewed as well.
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Research Products
(4 results)
