Raman spectroscopy is a technique used in analytical chemistry and physics to study vibrational, rotational, and other low-frequency modes in a system. Named after the Indian physicist Sir C.V. Raman who discovered the phenomenon in 1928, Raman spectroscopy provides information about molecular vibrations by measuring the inelastic scattering of monochromatic light.
Here is a breakdown of the process:
Incident light: A monochromatic (single wavelength) light, usually from a laser, is directed onto a sample.
Scattering interaction: When the light interacts with the molecules in the sample, most of it undergoes elastic scattering, meaning its energy remains unchanged (Rayleigh scattering). However, a small fraction undergoes inelastic scattering, and this is where Raman scattering occurs.
Energy changes: In Raman scattering, the energy of the scattered photons is changed due to the vibrational and rotational transitions of the molecules in the sample.
Detection: The scattered light is collected, and its spectrum is analyzed. The shifts in energy reveal information about the molecular vibrations and rotations within the sample.
Raman spectroscopy is valuable for identifying and characterizing chemical compounds, studying molecular structures, and investigating the interactions between molecules. It is widely used in various scientific fields, including chemistry, biology, material science, and pharmaceuticals. Raman spectroscopy provides a non-destructive and non-invasive way to obtain detailed information about the molecular composition of a sample.