Raman spectroscopy Rayleigh scattering

See also Electromagnetic Radiation Laser Applications in Eiectronic Spectroscopy Laser Spectroscopy Theory Linear Dichroism, Theory Muitiphoton Spectroscopy, Appiications Optical Frequency Conversion Raman Opticai Activity, Applications Raman Opticai Activity, Spectrometers Raman Opticai Activity, Theory Raman Spectrometers Rayleigh Scattering and Raman Spectroscopy, Theory Symmetry in Spectroscopy, Effects of. 

See also Biochemical Applications of Raman Spectroscopy Far-IR Spectroscopy, Applications IR Spectroscopy, Theory IR Spectrometers IR Spectroscopy Sample Preparation Methods Raman Spectrometers Rayleigh Scattering and Raman Spectroscopy, Theory. 

Perhaps the best known and most used optical spectroscopy which relies on the use of lasers is Raman spectroscopy. Because Raman spectroscopy is based on the inelastic scattering of photons, the signals are usually weak, and are often masked by fluorescence and/or Rayleigh scattering processes. The interest in usmg Raman for the vibrational characterization of surfaces arises from the fact that the teclmique can be used in situ under non-vacuum enviromnents, and also because it follows selection rules that complement those of IR spectroscopy. 

In either case, the information on the vibrational transition is contained in the energy difference between the excitation radiation and the inelastically scattered Raman photons. Consequently, the parameters of interest are the intensities of the lines and their position relative to the Rayleigh line, usually expressed in wavenumbers (cm 1). As the actually recorded emissions all are in the spectral range determined by the excitation radiation, Raman spectroscopy facilitates the acquisition of vibrational spectra through standard VIS and/or NIR spectroscopy. 

Figure 9.27 In Raman spectroscopy, light from a laser is shone at a sample. It is monochromated at a frequency of v0. Most of the light is transmitted. Most of the scattered light is scattered elastically, so its frequency remains at v0 this is Rayleigh scattered light. Raman scattered light has a frequency V(SCattered) = v0 — vibration) The sample is generally in solution...

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