7.2 History of Raman Spectroscopy

Sir CV Raman

Figure 7.2.1 Dr. Chandrasekhara Venkata Raman in 1930. From Nobel Lectures, Physics 1922-1941, Elsevier Publishing Company, Amsterdam, 1965. This photo is in the public domain in the United States.

 

Learning Objectives

Describe the career of C.V. Raman, how he discovered the theory of Raman spectroscopy, and how he conducted experiments to demonstrate Raman scattering

Prior Knowledge and Skills

None

Key Terms

Quartz spectrograph

Raman scattering

Guided Inquiry

Read the online article from the American Chemical Society about Raman and his discovery (also available as a .pdf):

American Chemical Society International Historic Chemical Landmarks. (ret. 12/1/2018). The Raman Effect. (ret. 12/1/2018) 8 p. http://www.acs.org/content/acs/en/education/whatischemistry/landmarks/ramaneffect.html.

Read the Wikipedia entry on Raman:

https://en.wikipedia.org/wiki/C._V._Raman

7.2.1 Summarize the professional career of C.V. Raman.  Did he take a traditional route to get to academia?  What jobs did he hold?

7.2.2 How did Raman come up with the idea that led to his development of Raman spectroscopy?

7.2.3 What were the original light sources for Raman’s experiments?

7.2.4 What is a quartz spectrograph, and how did Raman use it in his Raman scattering experiments?

7.2.5 What new technology was responsible for making Raman spectroscopy into a practical tool?

Watch this video which provides a great visual demonstration of the Raman effect:


NanophotonGlobal. (January 6, 2017). Visual guide to Raman spectroscopy | Nanophoton. https://youtu.be/G1jXR5PhUc0

7.2.6 When a green laser is passed through a sample of water, what color is most of the scattered light?  If a filter is used to remove the green light, what color is the Raman scattered light for water?

Concept Check 7.2.1

If a violet laser is passed through a sample of water, do you think the Raman scattered light would still be red, like the example above?  Why or why not?

Summary

C.V. Raman was a talented Indian physicist with interests in music and scattered light which led to his discovery of Raman scattering. He was awarded the Nobel Prize in Physics in 1930. Raman showed that, although most light reflected from a substance was the same color or wavelength, a small amount of light experiences a color or wavelength shift when it is reflected.  Modern lasers made Raman spectroscopy viable as a technique for determining physical and chemical properties of materials (including geological materials).

References

American Chemical Society International Historic Chemical Landmarks. (ret. 12/1/2018). The Raman Effect. (ret. 12/1/2018) 8 p. http://www.acs.org/content/acs/en/education/whatischemistry/landmarks/ramaneffect.html.

NanophotonGlobal. (January 6, 2017). Visual guide to Raman spectroscopy | Nanophoton. https://youtu.be/G1jXR5PhUc0

Wikipedia contributors. (2018, November 28). C. V. Raman. In Wikipedia, The Free Encyclopedia. Retrieved 02:10, December 3, 2018, from https://en.wikipedia.org/w/index.php?title=C._V._Raman&oldid=871005159