|
|
| Home > JCE Print > Journal of Chemical Education > Issues >
2004
>
May
> |
|
In the Laboratory
|
|
|
|
Fluorescence and Light Scattering
|
Ronald J. Clarke and Anna Oprysa
School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia
|
|
May 2004
Vol. 81 No. 5
p. 705
|
|
|
|
|
|
|
| Abstract |
|
This experiment allows students to discover the fundamental experimental difference between fluorescence and light scattering; namely, that the wavelength of fluorescence is independent of the excitation wavelength whereas the wavelength of scattered light increases with increasing excitation wavelength. The students use this fact to identify the fluorescence, Rayleigh scattering, and Stokes Raman scattering bands of an aqueous solution of fluorescein. The wavenumber difference of the Raman scattering peak of the solvent water is then calculated and shown to agree well with the wavenumber of infrared absorption of liquid water at 3400 cm-1. The good agreement of the two values is explained by the initial and final energy levels being very similar in both cases, although the energy pathway followed is different for the two processes. Finally, the students predict the expected position of the anti-Stokes Raman scattering peak of water and show that it is not observable owing to the small population of the v = 1 vibrational state. The experiment requires inexpensive nonhazardous chemicals and is extremely reliable. It links three different spectroscopic techniques that are usually taught separately, fluorescence, Raman scattering, and infrared absorption, and encourages the development of students' fundamental understanding of spectroscopy in general.
|
| Supplement |
Instructions for the students, student laboratory report, and notes for the instructor are available.
|
 Contents |
JCE2004p0705W.doc (Microsoft Word)
|
| Download |
|
|
| More Information |
Citation |
Clarke, Ronald J.; Oprysa, Anna. J. Chem. Educ. 2004 81 705.
|
Keywords |
Fluorescence Spectrometry; IR Spectroscopy; Laboratory Instruction; Physical Chemistry; Raman Spectroscopy
|
History |
Created:
Last Updated: |
April 1, 2004
February 18, 2005
|
|
|
|
|
|
| Home > JCE Print > Journal of Chemical Education > Issues >
2004
>
May
> Page
705
|
|
|
| JCE HS CLIC |
|
Our Secondary School editors work hard to distill all the JCE materials to produce a fraction of particular interest to high school teachers. We call it CLIC.
|
| Contributions Welcome |
| JCE welcomes your submission |
| Advertisers |
| In recent years we have worked hard to better match our advertisers with our readers. When shopping for chemistry education materials, visit our advertisers' WWW sites first. |
| Be An Ambassador |
| Take JCE along on your outreach missions. Copies of the Journal, guest access to JCE Online, our publications catalog, and more are available for your participants. |
|
