2007 Fiscal Year Final Research Report Summary
UV-vis absorption spectra of powdered materials using optical waveguide spectroscopy
| Project/Area Number |
17350016
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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 |
Organic chemistry
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| Research Institution | The University of Tokyo |
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Principal Investigator |
OGAWA Keiichiro The University of Tokyo, Graduate School of Arts and Sciences, Associate Professor (50114426)
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| Co-Investigator(Kenkyū-buntansha) |
HARADA Jun The University of Tokyo, Graduate School of Arts and Sciences, Assitant Professor (00313172)
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| Project Period (FY) |
2005 – 2007
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| Keywords | Optical waveguide spectroscopy / Organic solid materials / Uv-vis absorption spectra / Diffuse reflectance spectra materials |
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| Research Abstract |
The UV-vis absorption spectrum of solid powdered materials is of great importance in chemistry and material science. However, there has been no way to obtain directly the absorption spectrum of powdered materials, because transmittance spectroscopy is not applicable. Accordingly, diffuse reflectance is measured. Recently, a spectroscopy utilizing an optical waveguide has attracted considerable attention as a new analytical tool. An incident light to the optical waveguide, which is usually a thin quartz plate, proceeds in the waveguide repeating total reflections. When a total reflection occurs, the so-called evanescent light emerges from the outer surface of the optical waveguide. The emerging distance is about a wavelength of the incident light. When the evanescent light is absorbed by the sample that is placed on the optical waveguide, the outgoing light from the optical waveguide decreases in intensity. As a result, an absorption spectrum of the sample on the optical waveguide is obtained. This spectrum is the absorption spectrum of the molecules that reside within a distance of 1 μm from the surface of the optical waveguide. This suggests that an absorption spectrum of solid powdered materials as they are can be obtained, if the powdered materials are placed on the optical waveguide. In accordance with this expectation, we were successful to obtain UV-vis absorption spectrum of powdered materials by the use of optical waveguide spectroscopy in some cases. We found that optical waveguide spectroscopy can be an excellent method for obtaining true absorption spectra of powdered materials as they are without any treatment. This method can be applied not only to fine powders but also to larger crystals.
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Research Products
(45 results)
