Raman effect, also known as Raman scattering, is a phenomenon in which light undergoes scattering by a molecule or a crystal, resulting in a change in its wavelength and frequency. The effect was first discovered by Indian physicist C. V. Raman in 1928.
When light interacts with a molecule or a crystal, some of the photons are absorbed by the atoms or molecules, while others are scattered in different directions. In the Raman effect, a small fraction of the scattered photons undergoes a change in energy, resulting in a shift in their wavelength and frequency. This shift is caused by the interaction between the incident light and the molecular vibrations and rotations in the sample.
The Raman effect is used to study the vibrational and rotational modes of molecules, as each mode gives rise to a specific frequency shift in the scattered light. By analyzing the Raman spectra, scientists can determine the chemical composition and structure of the sample.
The Raman effect has numerous applications in science and industry, including in the fields of chemistry, materials science, and biology. It is commonly used in spectroscopy to analyze the composition of materials, and in Raman microscopy to study biological samples and materials at the microscopic level.