Ramanspektroskopiaan

Ramanspektroskopiaan is an analytical technique used to determine the vibrational modes of a molecule. It is a spectroscopic method that utilizes inelastic scattering of monochromatic light, often from a laser, in relation to a sample. When light interacts with a molecule, most of it is scattered elastically, meaning the photons have the same energy before and after the interaction. However, a small fraction of the scattered light, known as Raman scattered light, has a different energy. This energy shift is due to the molecule absorbing or emitting energy during the interaction, which corresponds to its vibrational energy levels.

The Raman effect is typically weak, with only about one in a million to one in a billion photons undergoing inelastic scattering. The intensity of the Raman scattered light is dependent on the polarizability of the molecule's electron cloud. Molecules with a significant change in polarizability during a vibrational motion will exhibit a strong Raman signal. The spectrum obtained, a Raman spectrum, plots the intensity of the scattered light against the Raman shift, which is the difference in energy between the incident and scattered photons, usually expressed in wavenumbers (cm⁻¹).

Raman spectroscopy provides information about the molecular structure, chemical bonding, and molecular symmetry. It is a non-destructive technique and can be used to analyze a wide range of samples, including solids, liquids, and gases, often with minimal sample preparation. The technique is complementary to infrared (IR) spectroscopy, as the selection rules for Raman activity and IR activity are often mutually exclusive for a given vibrational mode, meaning a vibration that is active in Raman spectroscopy may be inactive in IR spectroscopy, and vice versa. This complementarity allows for a more complete characterization of molecular vibrations. Applications of Raman spectroscopy span various fields, including chemistry, physics, materials science, biology, and medicine, for tasks such as material identification, quality control, and chemical analysis.