Polarization Dependance of Vib Raman Scattering

This effect is known as the Raman enhancement and is commonly observed in Raman spectroscopy experiments. In summary, the polarization of the incident laser plays a crucial role in determining the intensity of Vibrational Raman Scattering, with the highest intensity observed when the plane of polarization is parallel to the line of sight of the CCD lens. This is due to the anisotropic polarizability of N2 and O2 molecules in air, which causes a greater degree of vibration when the electric field of the laser is aligned with the line of sight.
  • #1
Jimbone
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I'm trying to understand how the polarization of an incident laser, (280.5 nm YAG in this case horizontally polarized) effects Vibrational Raman Scattering. Consider this laser incident on atmosphereic lab air (I'm seeing N2 and O2 stokes lines shifted to about 300nm) with a CCD lense's line of sight radially intersecting the laser beam. Where (azimuthally) will I get the highest scattering intensity? On a plane parallel with the the polarization of the laser? Perpendicular? I know this has something to do with the polarizability of the gas molecules but I'm having a hard time seeing how this works. Any help would be greatly appreciated.
 
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  • #2
The highest scattering intensity will be observed when the plane of polarization of the incident laser is parallel to the line of sight of the CCD lens. This is due to the fact that the vibrational polarizability of N2 and O2 molecules in air is anisotropic (i.e. it depends on the direction of the electric field). When the electric field of the incident laser is aligned with the line of sight of the CCD lens, it will cause a greater degree of vibration in the molecules, resulting in higher intensity of the Raman scattering.
 

Related to Polarization Dependance of Vib Raman Scattering

1. What is the concept of "polarization dependence" in Vib Raman Scattering?

When studying Raman scattering, the polarization dependence refers to the change in the intensity of the scattered light when the polarization of the incident light is changed. In other words, the intensity of the scattered light is dependent on the orientation of the incident light's electric field.

2. How does the polarization dependence of Vib Raman Scattering differ from regular Raman Scattering?

In regular Raman scattering, the scattering intensity does not change with the polarization of the incident light. However, in Vib Raman scattering, the intensity of the scattered light is highly dependent on the polarization of the incident light due to the presence of vibrational modes in the sample.

3. What are the factors that affect the polarization dependence of Vib Raman Scattering?

The polarization dependence of Vib Raman scattering is affected by factors such as the orientation of the sample, the angle of incidence of the light, and the symmetry of the vibrational modes present in the sample.

4. Why is the study of polarization dependence important in Vib Raman Scattering?

The study of polarization dependence in Vib Raman scattering allows for the identification and characterization of vibrational modes in a sample. This information is crucial in various fields such as chemistry, materials science, and biology, as it can provide insight into the molecular structure and dynamics of a sample.

5. How is the polarization dependence of Vib Raman Scattering measured?

The polarization dependence of Vib Raman scattering is measured by rotating the polarization of the incident light and measuring the corresponding changes in the intensity of the scattered light. This can be done using specialized equipment such as a polarizer or a quarter-wave plate.

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