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Raman spectroscopy (/ ˈ r ɑː m ən /) (named after physicist C. V. Raman) is a spectroscopic technique typically used to determine vibrational modes of molecules, although rotational and other low-frequency modes of systems may also be observed. [1] Raman spectroscopy is commonly used in chemistry to provide a structural fingerprint by which ...
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Raman spectroscopy employs the Raman effect for substances analysis. The spectrum of the Raman-scattered light depends on the molecular constituents present and their state, allowing the spectrum to be used for material identification and analysis. Raman spectroscopy is used to analyze a wide range of materials, including gases, liquids, and ...
Rotational–vibrational spectroscopy is a branch of molecular spectroscopy that is concerned with infrared and Raman spectra of molecules in the gas phase. Transitions involving changes in both vibrational and rotational states can be abbreviated as rovibrational (or ro-vibrational ) transitions.
It states that no normal modes can be both Infrared and Raman active in a molecule that possesses a center of symmetry. This is a powerful application of group theory to vibrational spectroscopy, and allows one to easily detect the presence of this symmetry element by comparison of the IR and Raman spectra generated by the same molecule. [1]
Stimulated Raman spectroscopy, also referred to as stimulated Raman scattering (SRS), is a form of spectroscopy employed in physics, chemistry, biology, and other fields. . The basic mechanism resembles that of spontaneous Raman spectroscopy: a pump photon, of the angular frequency , which is scattered by a molecule has some small probability of inducing some vibrational (or rotational ...
A Raman band whose depolarization ratio is less than 0.75 is called a polarized band, and a band with a depolarization ratio equal to or greater than 0.75 is called a depolarized band. [4] [5] For a spherical top molecule in which all three axes are equivalent, symmetric vibrations have Raman spectral bands which are completely polarized (ρ = 0).
One of the ways to experimentally determine and is through Raman spectroscopy. [ 13 ] [ 14 ] As previously mentioned, the phonon frequencies used in the LST relation are those corresponding to the TO and LO branches evaluated at the gamma-point ( k = 0 {\displaystyle k=0} ) of the Brillouin zone .