Raman Spectroscopy: Unique Features & Benefits

In summary, Raman spectroscopy is a spectroscopy technique that is used to study molecules that have centre of inversion symmetry. It is complementary to infrared spectroscopy, which studies molecules that do not have centre of inversion symmetry.
  • #1
photon79
60
0
raman spectroscopy!

Hi, can anybody please tell what is the speciality of Raman spectroscopy and how it differs from other techniques?? does it have any uniqueness? more info is welcomed! thanks in advance.
 
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  • #3
Raman spectroscopy excites transitions forbidden by infrared spectroscopy as Raman transitions are bound by different selection rules.

Claude.
 
  • #4
Claude Bile said:
Raman spectroscopy excites transitions forbidden by infrared spectroscopy as Raman transitions are bound by different selection rules.

Claude.

I am not sure i get your point here. What are you talking about ? Could you clarify, please ?

I am no specialist on this but doesn't IR spectroscopy involve electronic energy transitions induced by the incoming IR photon, while Raman spectroscopy is just the phonon transitions induced by the scattering of a photon at the lattice-atoms ? By this scattering process, a phonon is either emitted or absorbed : ie the Stokes and anti-Stokes lines ?

marlon
 
  • #5
Raman scattering and IR speoectroscopy compliment each other when we are dealing with molecules having centre of inversion symmetry. In these molecules raman active lines are forbidden in IR and vice versa. Coming to vibrational and rotational lines in a spectrum..vibrations are obsorved in infrared region and rotations in microwave region,,but when we look at the pure vibrational spectra we can also see rotational lines which should not be there as they belong to microwave region..why does this happen?
 
  • #6
Marlon, infrared spectroscopy excites vibrational energy states in a given molecule (although there are electronic transitions that are excited by infrared wavelengths, the term infrared spectroscopy usually refers to vibrational transitions. The more correct name for infrared spectroscopy is vibrational or rovibrational spectroscopy).

A vibrational state is excited through infrared spectroscopy if there is a variation in the dipole moment of the molecule as the molecule vibrates. Some vibrations (such as symmetric vibrations) are not infrared active because their dipole moment is constant.

A vibrational state is excited through Raman spectroscopy if there is a variation in the polarisability of the molecule.

Photon79, you are not allowed to double post in these forums, I'm pretty sure marlon already warned you once before. Read my response on the other thread and if you have further questions, post them there.

Claude.
 
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  • #7
Thanks Claude for the explanation. I also looked it up on Wikipedia, and i do realize where i was wrong.

Thanks again

marlon
 
  • #8
Not a problem Marlon, :smile: .

Claude.
 

1. What is Raman spectroscopy?

Raman spectroscopy is a technique used to study the vibrational modes of molecules by measuring the scattered light from a sample. It involves shining a laser on a sample and analyzing the inelastic scattered light, which provides information about the chemical composition and structure of the sample.

2. What are the unique features of Raman spectroscopy?

Raman spectroscopy has several unique features, including its ability to provide information about both the chemical composition and structure of a sample, its non-destructive nature, and its sensitivity to even small changes in the sample's molecular structure.

3. What are the benefits of using Raman spectroscopy?

Raman spectroscopy has many benefits, such as its versatility in analyzing a wide range of samples, its ability to provide real-time results, and its non-contact and non-destructive nature, which makes it suitable for analyzing delicate or valuable samples.

4. How does Raman spectroscopy differ from other spectroscopic techniques?

Raman spectroscopy differs from other spectroscopic techniques in that it measures the inelastic scattered light rather than the absorbed light, making it more sensitive to changes in the sample's molecular structure. Additionally, it does not require extensive sample preparation and can be used on a variety of sample types.

5. What are the common applications of Raman spectroscopy?

Raman spectroscopy has many applications in various fields, including pharmaceuticals, forensics, materials science, and environmental analysis. It can be used to identify unknown substances, analyze the composition of complex mixtures, and monitor chemical reactions in real-time.

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