Measurement of the Index of Refraction of Solids by UV-Vis Spectroscopy
- ASSOC WESTERN UNIVERSITY
- BATTELLE (PACIFIC NW LAB)
- University of Great Falls
The refractive index (n) of a liquid is commonly measured in the chemistry laboratory using a refracrometer at a single wavelength (589 nm) and temperature (20 degrees C). The refractive index of a solid material is sometimes estimated by index matching to known liquids; when a solid ''disappears'' in a liquid medium, it is assumed to have the same index of refraction as the surrounding liquid. In both cases students may miss the fact that ''n'' is actually not just a single number, but rather a function of wavelength and temperature. In this laboratory, we employ UV-vis transmission spectra to obtain the dispersion curve (i.e., refractive index vs wavelength) of a solid material using a well-characterized organic solvent as a reference compound. While there are many experiments in the chemical education literature concerning the measurement and use of refractive index (3-6), we are unaware of any that employ the spectroscopic method used here. This exercise is most appropriate for use in the upper-division undergraduate physical chemistry lab, but could also be used in sophomore-level organic and analytical chemistry labs.
- Research Organization:
- Pacific Northwest National Lab., Richland, WA (US) (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 15005815
- Report Number(s):
- PNNL-SA-39822; KC0201050; TRN: US200324%%228
- Journal Information:
- Journal of Chemical Education, Vol. 79, Issue 5; Other Information: PBD: 1 May 2002
- Country of Publication:
- United States
- Language:
- English
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