Explanation

Also known as Raman scattering, it refers to the phenomenon that the frequency of light waves changes after being scattered. When a beam of light passes through an uneven medium, some of the beams will deviate from their original direction and disperse, which is called light scattering. Under the action of human light, most photons are elasticity scattering, which is called Rayleigh scattering. Under Rayleigh scattering, the scattered photons have the same energy, frequency and wavelength as the incoming photons. However, there is a small portion of scattered photons (approximately one out of ten million photons), and the frequency of the scattered photons changes due to energy exchange between the incident photons and the dielectric molecules. Then light with lower or higher frequency is scattered, which is called Raman scattering. Raman scattering is the inelastic scattering of light by atomic system. Raman scattering is very weak, and its intensity is about one thousandth of Rayleigh scattering. A spectral line with a frequency less than the frequency of the incident light is called a Stokes line, while a spectral line with a frequency greater than the frequency of the incident light is called an anti Stokes line. Generally, the spectrum formed by combining Rayleigh scattering and Raman scattering is called Raman spectroscopy. Raman scattering provides an important means to study the structure of crystal or molecule. The Raman scattering method can quickly determine the natural frequency of molecular vibration, and determine the symmetry of molecules, internal force of molecules, etc.

Classification