Question

What is raman effect ? And experimental arrangement or raman effect?

Answer 1

Answer:

Raman scattering or the Raman effect /ˈrɑːmən/ is the inelastic scattering of photons by matter, meaning that there is an exchange of energy and a change in the light's direction. Typically this involves vibrational energy being gained by a molecule as incident photons from a visible laser are shifted to lower energy. This is called normal Stokes Raman scattering. The effect is exploited by chemists and physicists to gain information about materials for a variety of purposes by performing various forms of Raman spectroscopy. Many other variants of Raman spectroscopy allow Rotational energy to be examined (if gas samples are used) and electronic energy levels may be examined if an X-ray source is used in addition to other possibilities. More complex techniques involving pulsed lasers, multiple laser beams and so on are known.

Light has a certain probability of being scattered by a material. When photons are scattered, most of them are elastically scattered (Rayleigh scattering), such that the scattered photons have the same energy (frequency, wavelength and color) as the incident photons but different direction. Rayleigh scattering usually has an intensity in the range 0.1% to 0.01% relative to that of a radiation source. An even smaller fraction of the scattered photons (approximately 1 in 10 million) can be scattered inelastically, with the scattered photons having an energy different (usually lower) from those of the incident photons—these are Raman scattered photons.[1] Because of conservation of energy, the material either gains or loses energy in the process.

Rayleigh scattering was discovered and explained in the 19th century. The weaker Raman effect is named after Indian scientist C. V. Raman, who discovered it in 1928 with assistance from his student K. S. Krishnan. Raman was awarded the Nobel prize in Physics in 1930 for his discovery although Grigory Landsberg and Leonid Mandelstam observed the effect in crystals the same year as Raman. The effect had been predicted theoretically by Adolf Smekal in 1923.

Answer 2

Answer:

The inelastic scattering of photons by matter, also known as Raman scattering or the Raman effect, results in both an energy exchange and a change in the direction of the light.

Explanation:

• The inelastic scattering of photons by matter, also known as Raman scattering or the Raman effect, results in both an energy exchange and a change in the direction of the light.
• Most photon scattering is elastic (Rayleigh scattering), where the scattered photons have a different direction but the same energy (frequency, wavelength, and colour) as the input photons.
• The experimental arrangement of the Raman effect was discussed by Sir C. V. Raman as:
• Sir C. V. Raman carried out a series of tests by shining sunlight over a liquid probe.
• He employed an excitation filter that was monochromatic, allowing only light of a particular wavelength to reach the probe.
• The scattered light that was measured had a wider spectrum and more wavelengths.
• Behind the probe, an additional filter called an emission filter allowed for the blocking of incident wavelengths.
• Now it was possible to discern easily between the incident light and the detected residual scattered light.

Thus, An energy exchange and a shift in the direction of the light occur as a result of the inelastic scattering of photons by matter, also referred to as the Raman effect or Raman scattering.

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