Raman spectroscopy chemical imaging

Raman spectroscopy allows chemical identification of single phases and in the imaging mode a description of the morphology. Raman bands characteristic of the two main components PA and PTFE are easily distinguishable, as shown in Figure 6, where pure materials have been used from which to record reference spectra. To identify PTFE in the spectra of the bearing the symmetric C-F... 

To perform chemical imaging of sample surfaces, FT spectrometers can be coupled with a microscope or macrochamber with an FPA detector. CIS are available for Raman, NIR, and MIR spectroscopy. Figure 15 illustrates an optical arrangement for chemical imaging. 

FT Spectrometers FT spectrometers (Figure 3) differ from scanning spectrometers by the fact that the recorded signal is an interferogram [14] (see Chapter 6.2). They can be coupled to a microscope or macrochamber with an FPA detector. FT chemical imaging systems (CISs) are available for Raman, NIR, and IR spectroscopy. However, they can only be considered as research instruments. For example, most IR imaging systems are FT spectrometers coupled to microscopes. This type of spectrometer allows the acquisition of spectra in reflection, attenuated total reflection (ATR), or transmission mode. 

To date, a number of chemically selective near-field imaging methods have been demonstrated. Near-field contrast mechanisms that rely on electronic spectroscopy (UV-visible absorption and fluorescence),204 vibrational spectroscopy (IR absorption and Raman spectroscopies), dielectric spectroscopy (microwave dispersion), and nonlinear spectroscopy (second harmonic generation) have all been demonstrated at length scales well below the diffraction limit of light. 

Since the first edition of the book, the expansion of Raman spectroscopy as an analytical tool has continued. Thanks to advances in laser sources, detectors, and fiber optics, along with the capability to do imaging Raman spectroscopy, the continued versatility of FT-Raman, and dispersive based CCD Raman spectrometers, progress in Raman spectroscopy has flourished. The technique has moved out of the laboratory and into the workplace. In situ and remote measurements of chemical processes in the plant are becoming routine, even in hazardous environments. 

Abstract Within last decade both IR and Raman spectroscopy gained the potential of imaging the chemical heterogeneity of material surfaces. 

Fourier-Transform Infrared (FTIR) spectroscopy as well as Raman spectroscopy are well established as methods for structural analysis of compounds in solution or when adsorbed to surfaces or in any other state. Analysis of the spectra provides information of qualitative as well as of quantitative nature. Very recent developments, FTIR imaging spectroscopy as well as Raman mapping spectroscopy, provide important information leading to the development of novel materials. If applied under optical near-field conditions, these new technologies combine lateral resolution down to the size of nanoparticles with the high chemical selectivity of a FTIR or Raman spectrum. These techniques now help us obtain information on molecular order and molecular orientation and conformation [1],... 

Tripathi GNR (1983) Time resolved resonance Raman spectroscopy of radiation-chemical processes. In Talmi Y (ed) Multichannel Image detectors, vol 2 ACS Symposium Series No. 236, American Chemical Society, Washington D.C. 

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