Search results
Results from the WOW.Com Content Network
Energy-level diagram showing the states involved in Raman spectra. 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]
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]
Raman amplification / ˈ r ɑː m ən / [1] is based on the stimulated Raman scattering (SRS) phenomenon, when a lower frequency 'signal' photon induces the inelastic scattering of a higher-frequency 'pump' photon in an optical medium in the nonlinear regime. As a result of this, another 'signal' photon is produced, with the surplus energy ...
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 ...
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 ...
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).
Amongst his numerous achievements was his historic landmark paper with Bergmann of 1967 about the first successful use of Transmission Raman spectroscopy for chemical analysis of Organic solids, [3] e.g. pharmaceutical powders, which has become routine industry practice since that approach was "rediscovered" in 2006.
Transmission Raman spectroscopy (TRS) is a variant of Raman spectroscopy which is advantageous in probing bulk content of diffusely scattering samples. Although it was demonstrated in the early days of Raman spectroscopy [ 1 ] it was not exploited in practical settings until much later, probably due to limitations of technology at the time.