A review of infrared spectroscopy in microarchaeology: Methods, applications, and recent trends

Introductory Chapter: Infrared Spectroscopy - A Synopsis of the Fundamentals and Applications

“…Accordingly, and since electromagnetic radiations travel at a constant speed in vacuum which is the speed of light (c, 2.997 924 58 × 10 8 m s −1 ), the frequency of IR radiations is therefore lower compared to that of the visible light, applying the formula υ = c/λ where υ = the frequency of light, c = the speed of light, and λ = the wavelength of light. This in turn means that energy associated with the IR radiations is inferior to that of the visible light and greater than that of microwaves, for instance [5][6][7][8].…”

“…Normal modes of vibrations for such a molecule can be obtained following the exclusion of the DoF for the translational and rotational motions and are equal to 3N-6. As the rotation of a linear molecule around the bond axis does not involve a change in energy and hence cannot be observed, the number of internal motions would be 3N-5 [1,[8][9][10][11].…”

“…However, after the microelectronic revolution, the capabilities and availability of these instruments have been greatly improved. In addition to the noticeable speed in acquiring spectra, improved signal to noise ratio, high resolution, accuracy, and reproducibility, FT-IR offers two major pluses over the classical dispersive instruments [6][7][8][17][18][19][20]:…”

“…In general, coupling of an IR spectrophotometer with an optical microscope is known as FT-IR microscopy. Collection of the specular reflection spectrum is performed using such a setup and is commonly known as micro FT-IR [8,19,[22][23][24].…”

“…Diffuse reflectance spectroscopy (DRS): this is a combination between internal and external reflections and originates from rough surfaces (powders) reflecting light in different directions. Having diffuse reflectance exploited in IR FT spectroscopy is known as DRIFTs [8,25].…”