Raman Spectroscopy Essay

explanatory Essay
954 words
954 words

. After reflection of the two beams, they recombine at the beam-splitter. Depending on the location of the moving mirror, difference in the optic paths are generated. The two beams interfere constructively and therefore lead to a maximum detector response when they are in phase with each other. The beams interfere destructively when they are out of phase with each other. (14)(15) Figure 1.3 – Schematic representation of the operation of a FTIR spectrometer equipped with a Michelson interferometer. The interferogram obtained from a monochromatic source is illustrated (John 2006 (15)).

Raman spectroscopy
Raman spectroscopy is, besides IR spectroscopy, one of the two spectroscopic methods used for vibrational analysis. Both techniques are used to provide a fingerprint of molecules by generating spectra. The main difference is that IR spectroscopy is based on absorption of photons with a frequency equal to the vibrational frequency of functional groups, whereas Raman spectroscopy is based on inelastic scattering of monochromatic light. (14) Also different selection rules apply on these techniques, meaning the techniques are …show more content…

In this essay, the author

  • Explains x-ray powder diffraction (xrpd) is an interesting analytical technique for the identification of crystalline substances.
  • Explains how the two beams recombine at the beam-splitter, resulting in a maximum detector response when they are in phase with each other.
  • Explains that raman spectroscopy is a complementary technique for vibrational analysis, whereas ir spectra are based on inelastic scattering of monochromatic light.
  • Explains that differential scanning calorimetry (dsc) is a thermal analytical technique, often used for the identification and characterization of polymorphic forms.
  • Explains the two types of light scattering, which are fast and easy to perform, but require low particle concentrations.

The area under the curve represents the energy required to compensate for the thermal events of the sample. Some instruments represent endothermic processes (melting) as downward curves and exothermic processes (crystallisation) as upwards peaks, while other instruments show it in the opposite way. (18) DSC can be used to evaluate different thermal events including melting, solid-state transitions, crystallization, glass transitions … (19) DSC may therefore be used to differentiate between polymorphs according to their melting point or to examine the transformation of metastable systems. It is essential though to confirm the results of DSC with other characterization techniques such as Raman spectroscopy, IR spectroscopy and X-ray diffraction.

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