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Topic: Raman spectroscopy


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  Raman spectroscopy - Wikipedia, the free encyclopedia
Raman spectroscopy is a spectroscopic technique used in condensed matter physics and chemistry to study vibrational, rotational, and other low-frequency modes in a system.
Thus, Raman spectroscopy is suitable for the microscopic examination of minerals, materials such as polymers and ceramics, cells and proteins.
Raman won the Nobel Prize in Physics in 1930 for this discovery, accomplished using filtered sunlight as a monochromatic source of photons, a colored filter as a monochromator, and a human eye as detector.
en.wikipedia.org /wiki/Raman_spectroscopy   (1572 words)

  
 Raman Spectroscopy
Raman spectroscopy takes advantage of the Raman effect to study low-frequency modes in a system like vibration and rotation.
The three main advantages of Raman spectroscopy over other types of spectroscopy are that you don't have to pretreat your samples; Raman spectroscopy is not interfered with by water, and samples are not destroyed in the process.
Raman spectroscopy is often used in chemistry to identify substances or to study changes in chemical bonding, such as when a substrate is added to an enzyme.
www.iscid.org /encyclopedia/Raman_Spectroscopy   (263 words)

  
 MIT Spectroscopy - Raman Spectroscopy of Breast Cancer
Further, Raman spectroscopy is particularly amenable to in vivo measurements as the powers and excitation wavelengths used are non-destructive to the tissue and have a relatively large penetration depth.
Modeling is based on the assumptions that the Raman spectrum of a mixture is a linear combination of the spectra of its components and that signal intensity and chemical concentration are linearly related.
The Raman spectra were fit to a linear combination of the basis spectra using an ordinary least-squares minimization algorithm with a non-negativity constraint.
web.mit.edu /spectroscopy/research/biomedresearch/Raman_breast.html   (1397 words)

  
 Raman Spectroscopy
Raman spectroscopy is a method of chemical analysis that enables real-time reaction monitoring and characterization of compounds in a non-contact manner.
Because the intensity of the Raman signal is inversely proportional to the fourth power of the excitation wavelength, it is advantageous to use as short a wavelength as possible.
The shortest wavelengths commonly used in Raman spectroscopy are in the visible region (532 and 632.8 nm).
www.kosi.com /raman/index.html   (263 words)

  
 Raman Spectroscopy Tutorial
The difference in energy between the incident photon and the Raman scattered photon is equal to the energy of a vibration of the scattering molecule.
Raman scatter is partially polarized, even for molecules in a gas or liquid, where the individual molecules are randomly oriented.
Resonance Raman spectroscopy is also a major probe of the chemistry of fullerenes, polydiacetylenes and other "exotic" molecules which strongly absorb in the visible.
www.kosi.com /raman/resources/tutorial   (2108 words)

  
 Raman Spectroscopy
Raman scattered light is frequency-shifted with respect to the excitation frequency, but the magnitude of the shift is independent of the excitation frequency.
The shape of an excitation in a material, for example a vibration pattern of the atoms in a molecule, and the polarization dependence of the scattering, are determined by the equilibrium structure of the material through the rules of group theory.
The term "Raman scattering experimen" might well be shorthand for the determination of the selection rules for light-scattering from a sample, in the event that the incident and scattered light have different frequencies.
physics.nist.gov /Divisions/Div844/facilities/raman/Ramanhome.html   (3333 words)

  
 Raman Scattering
The sketch below is an idealized depiction of a Raman line produced by interaction of a photon with a diatomic molecule for which the rotational energy levels depend upon one moment of inertia.
Raman discovered the inelastic scattering phenomenon which bears his name in 1928 and for it he was awarded the Nobel Prize for Physics in 1930.
Raman scattering produces scattered photons which differ in frequency from the radiation source which causes it, and the difference is related to vibrational and/or rotational properties of the molecules from which the scattering occurs.
hyperphysics.phy-astr.gsu.edu /hbase/atmos/raman.html   (594 words)

  
 Raman Spectroscopy & Laser Diode Technology
Raman spectroscopy is an analytical technique based on detection of scattered light and used for a variety of applications involving solid, liquid, and gas samples.
A small portion of the scattered light exhibits a slight shift in wavelength due to molecular vibrations in the sample, and this wavelength shift is used to analyze the sample.
Raman spectroscopy involves shining a laser onto a sample and examining the interaction between this light and the chemical bonds in the sample.
www.powertechnology.com /ramanspectroscopy.asp   (304 words)

  
 FAQs
Classical concept of Raman scattering: When a beam of light interacts with a material, part of it is transmitted, part it is reflected, and part of it is scattered.
In conventional Raman spectroscopy, visible lasers are used (e.g., Ar+, Kr+, Nd:YAG, He-Ne, diode) to stimulate the molecules to high-energy " virtual" states of excitation.
A Raman photon is emitted if a molecule then undergoes a transition to a higher vibrational energy state than its original state (Stokes-Raman), or to a lower energy vibrational state (Anti-Stokes Raman).
epsc.wustl.edu /haskin-group/Raman/faqs.htm   (574 words)

  
 Raman Spectroscopy   (Site not responding. Last check: 2007-10-20)
In Raman spectroscopy photons are scattered wheras in IR they are not.
It is the Raman scattered photons that Raman spectroscopy is based upon.
Raman scattering is not very efficient as is evidenced by this scattering only being 1 in 10 million; therefore, a laser is commonly used as the exciting light.
www.sas.upenn.edu /~rebryant/Raman_Spectroscopy.html   (403 words)

  
 Process Raman Spectroscopy | Infrared Spectroscopy | IR Spectroscopy | Axiom Analytical   (Site not responding. Last check: 2007-10-20)
Raman spectroscopy offers the major advantage of mid-IR - in the form of the distinct function group related bands - without the disadvantages.
For several years, we at Axiom monitored the progress of Raman spectroscopy, waiting for the capabilities of the basic instrumentation to reach the point where reliable process Raman was more than a distant dream.
RFP-500, the first Raman probe to be designed specifically for use under the wide ranging conditions present in most chemical process installations.
www.goaxiom.com /ab-101.html   (795 words)

  
 InPhotonics: What is Raman spectroscopy?
Raman spectroscopy provides information about molecular vibrations that can be used for sample identification and quantitation.
Raman spectroscopy can be used to measure bands of symmetric linkages which are weak in an infrared spectrum (e.g.
Raman bands arise from an oscillating induced dipole caused by light waves interacting with the polarizability ellipsoid of a vibrating molecule.
www.inphotonics.com /raman.htm   (623 words)

  
 Thermo Scientific - Raman Spectroscopy
Raman spectroscopy utilizes the phenomenon of inelastic light scattering to perform non-destructive chemical analysis at macro- and microscopic levels.
Raman spectroscopy is applied to a wide range of samples that includes organic and inorganic materials.
Raman gives important information about a molecules structure that can be used to supply accurate molecular identification of unknowns, and can be used in quantitative and conformational analysis of your samples.
www.thermo.com /com/cda/technology/detail/1,,1000000010201,00.html   (240 words)

  
 Raman Spectroscopy
In the discussion of Raman spectroscopy, we use language from particle theory and we say that a photon is scattered by the molecular system.
Raman Spectroscopy is based on the Raman effect, which is the inelastic scattering of photons by molecules.
For highly symmetric polyatomic molecules possessing a center of inversion (such as benzene) it is observed that bands that are active in the IR spectrum are not active in the Raman spectrum (and vice-versa).
carbon.cudenver.edu /public/chemistry/classes/chem4538/raman.htm   (2082 words)

  
 Resonance Raman spectroscopy - Wikipedia, the free encyclopedia
RR spectroscopy is in an improvement of traditional Raman spectroscopy that has increased sensitivity and is better suited for the study of complicated systems.
Typically, in Raman spectroscopy high intensity laser radiation with wavelengths in either the visible or near-infrared regions of the spectrum is passed through a sample.
In Raman spectroscopy, the incoming photon causes a momentary distortion of the electron distribution around a bond in a molecule, followed by reemission of the radiation as the bond returns to its normal state.
en.wikipedia.org /wiki/Resonance_Raman_spectroscopy   (2950 words)

  
 WellDog, Inc: Raman_Spectroscopy_Technical_Brief   (Site not responding. Last check: 2007-10-20)
Raman spectroscopy was invented after the discovery of the Raman Effect in 1928, for which Sir Chandrasekhra Venkata Raman won the Nobel Prize in Physics in 1930.
Raman spectroscopy observes these colors by collecting the scattered light and then separating and detecting the colors that make up the light.
As a result, in contrast to infrared systems Raman spectroscopy is not overly sensitive to water — an advantage when analyzing materials in systems such as coalbed reservoirs that contain water.
www.welldog.com /index.cfm?fuseaction=page.&page=Raman_Spectroscopy_Technical_Brief   (854 words)

  
 [No title]
Raman spectroscopy enables the study of vibrations in molecules and solids through the interaction of light with the vibrations.
Raman spectroscopy was first invented about 75 years ago, in 1928, by Chandrasekhara Venkata Raman.
One of the concerns at the time (private communication with Dr. Etz) was that micro-Raman spectroscopy might not be the same as traditional Raman spectroscopy, since it was performed through a microscope and on such a small (micron-sized) volume of material.
www.physics.ncsu.edu /optics/nanoRaman/nanoRaman.html   (344 words)

  
 Raman Spectroscopy Solutions
Resonance Raman spectroscopy is also an important probe of the chemistry of metal centred complexes, fullerenes, polydiacetylenes and other "exotic" molecules which strongly absorb in the visible.
In Raman microscopy, a research grade optical microscope is coupled to the excitation laser and the spectrometer, thus producing a platform capable of obtaining both conventional images and in addition generating Raman Spectra from sample areas approaching the diffraction limit (~1 micron).
Raman spectroscopists, when using CW lasers, often make us of long exposure times (1 sec to 20 minutes) in order to reach a resired signal to shot noise ratio, and in those instances a multi-MHz readout camera is not required.
www.andor.com /chemistry/?app=64   (2938 words)

  
 Raman Spectroscopy
The suitability of a Fiber optic Raman spectrometer for in-situ measurements is demonstrated.
The basic measurements involved in Fiber optic Raman spectroscopy are measurement of intensities of scattered radiation, from the material under investigation, as a function of wavelength or frequency.
Raman Spectrum diagnostic tests conducted in the present investigation establishes the suitability of the fiber optic portable Raman Spectrometer for field and in-situ tests.
www.geocities.com /micromechanic/Raman/index.html   (444 words)

  
 Journal of Analytical-Science.com : Raman Spectroscopy
Raman studies of the lustre films of different ceramics excavated from Fust√Ęt (near Cairo, Egypt, 11-12th century) or from the Silk Road (Termez, 13-14th centuries) showed that they associate many layers of different compositions (with or without cassiterite).
Raman spectroscopy uses a laser to probe the vibrational energy levels of a molecule or crystal.
Raman spectroscopy is similar to infrared (IR or FT-IR) spectroscopy.
www.analytical-science.com /Journal/ramanspectroscopy_2004.htm   (785 words)

  
 Raman Spectroscopy   (Site not responding. Last check: 2007-10-20)
Raman spectroscopy is the measurement of the wavelength and intensity of inelastically scattered light from molecules.
The Raman scattered light occurs at wavelengths that are shifted from the incident light by the energies of molecular vibrations.
Because Raman scattering is a weak process, a key requirement to obtain Raman spectra is that the spectrometer provide a high rejection of scattered laser light.
elchem.kaist.ac.kr /vt/chem-ed/spec/vib/raman.htm   (343 words)

  
 Renishaw - Structural and chemical analyser for SEM   (Site not responding. Last check: 2007-10-20)
Laser Raman spectroscopy is an analytical technique that uses light-scattering to identify molecular vibrations in a sample, revealing vital information about a sample's chemical structure and physical state.
This process is known as Raman scattering and the changes in frequencies correspond to vibrational energy levels in the sample, which depend on a sample's chemical structure and physical state.
Raman spectroscopy solves a variety of analytical problems across a wide range of applications, including polymer coatings, semiconductors, pharmaceuticals, diamond films, composites and ceramics, as well as forensic, geological, gemological, art, archaeological, medical, and biomedical applications.
www.renishaw.com /client/product/UKEnglish/PGP-1078.shtml   (606 words)

  
 SwRI: Near-infrared Raman Microscopy is being developed to provide a diagnosis tool for early cancer detection.
Raman spectroscopy has a potential to detect the molecular changes of tissue caused by cancer and, therefore, to allow the detection of cancerous or precancerous lesions at a much earlier stage.
Raman imaging microscopy is being developed at SwRI to provide a label-free, nondestructive, and noncontact imaging tool to monitor drug uptake and subcellular distribution in live cells.
Raman imaging microscopy can also be used to develop in-vitro assays to determine the absorption, distribution, metabolism, and excretion (ADME) properties of a candidate drug.
www.swri.org /4org/d10/bioeng/bioeng/raman.htm   (478 words)

  
 SPACE.com -- Life's Chemical Fingerprints -- Astrobiology Tech
A prototype of the Mars Microbeam Raman Spectrometer.
Scientists believe Raman spectroscopy is more likely to find minerals indicating conditions conducive to life than it is to find unambiguous evidence of life itself, past or present.
A planetary Raman spectrometer would press a probe against a sample, or perhaps plunge a fiber optic cable into the soil, then fire the laser repeatedly as the probe scanned the sample.
www.space.com /searchforlife/raman_010425.html   (1459 words)

  
 Bahram Roughani - Raman Lab
Raman spectroscopy laboratory at Kettering University, was established in 1996.
Raman Spectroscopy is an inelastic scattering of light due to light-matter interaction.
Raman spectroscopy analysis of these superlattice structures are aiming at surface roughness analysis of multilayered artificial structures.
www.kettering.edu /~broughan/homepage/raman.htm   (1007 words)

  
 Raman spectroscopy: a complex technology moving from lab to the clinic — and before too long, the marketplace - ...
Raman spectroscopy (RS) is a non-destructive laser technique that enables scientists to gather detailed information about the molecular composition of an object or substance.
Puppels, whose research focuses on clinical in vitro and in vivo applications of Raman spectroscopy, is also chief technology officer and managing director of River Diagnostics, which he co-founded in 2002 to ensure that research begun in the laboratory would result in actual products used by clinicians.
While experts interviewed for this article use Raman in different ways, they were in agreement on one point: Raman spectroscopy is making a determined march from the academic laboratory, into the clinic and ultimately, the marketplace.
www.opticsreport.com /content/article.php?article_id=1018   (2504 words)

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