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An infrared spectroscopy correlation table (or table of infrared absorption frequencies) is a list of absorption peaks and frequencies, typically reported in wavenumber, for common types of molecular bonds and functional groups.
The infrared portion of the electromagnetic spectrum is usually divided into three regions; the near-, mid- and far-infrared, named for their relation to the visible spectrum. The higher-energy near-IR, approximately 14,000–4,000 cm −1 (0.7–2.5 μm wavelength) can excite overtone or combination modes of molecular vibrations .
Infrared tracking, also known as infrared homing, refers to a passive missile guidance system, which uses the emission from a target of electromagnetic radiation in the infrared part of the spectrum to track it. Missiles that use infrared seeking are often referred to as "heat-seekers" since infrared (IR) is just below the visible spectrum of ...
This radiation is absorbed by molecular vibrations, where the different atoms in a molecule vibrate around their equilibrium positions. This range is sometimes called the fingerprint region, since the mid-infrared absorption spectrum of a compound is very specific for that compound. Near-infrared, from 120 THz to 400 THz (2,500–750 nm ...
The region beyond 50 μm (200 cm −1) became known as the far-infrared region; at very long wavelengths it merges into the microwave region. Measurements in the far infrared needed the development of accurately ruled diffraction gratings to replace the prisms as dispersing elements, since salt crystals are opaque in this region.
AFM-IR enables nanoscale infrared spectroscopy, [52] i.e. the ability to obtain infrared absorption spectra from nanoscale regions of a sample. Chemical compositional mapping AFM-IR can also be used to perform chemical imaging or compositional mapping with spatial resolution down to ~10-20 nm, [18] limited only by the radius of the AFM tip. In ...
Near-IR absorption spectrum of dichloromethane showing complicated overlapping overtones of mid IR absorption features. Near-infrared spectroscopy (NIRS) is a spectroscopic method that uses the near-infrared region of the electromagnetic spectrum (from 780 nm to 2500 nm). [1]
The infrared atmospheric window is an atmospheric window in the infrared spectrum where there is relatively little absorption of terrestrial thermal radiation by atmospheric gases. [1] The window plays an important role in the atmospheric greenhouse effect by maintaining the balance between incoming solar radiation and outgoing IR to space.