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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 spectrum of a sample is recorded by passing a beam of infrared light through the sample. When the frequency of the IR matches the vibrational frequency of a bond or collection of bonds, absorption occurs. Examination of the transmitted light reveals how much energy was absorbed at each frequency (or wavelength).
Two-dimensional infrared spectroscopy (2D IR) is a nonlinear infrared spectroscopy technique that has the ability to correlate vibrational modes in condensed-phase systems. This technique provides information beyond linear infrared spectra, by spreading the vibrational information along multiple axes, yielding a frequency correlation spectrum.
The AFM-IR technique can simultaneously provide complementary measurements of the mechanical stiffness and dissipation of a sample surface. When infrared light is absorbed by the sample the resulting rapid thermal expansion excites a "contact resonance" of the AFM cantilever, i.e. a coupled resonance resulting from the properties of both the ...
If the sample is too absorbent, then it can be diluted with a nonabsorbent material such as potassium bromide, potassium chloride, etc. The particle size should be smaller than the wavelength of the incident light in order to minimize Mie scattering , so this would infer that it should be less than 5 μm for mid-infrared spectroscopy.
The sample is in direct contact with an ATR crystal. As the IR beam reaches onto the ATR crystal, it extends beyond the crystal surface and protrudes into the sample at a shallow depth (0.5-5 μm). The sample absorbs some of the energy of the IR beam as the wave is internally reflected between the ATR crystal and the sample.
A common spectroscopic method for analysis is Fourier transform infrared spectroscopy (FTIR), where chemical bonds can be detected through their characteristic infrared absorption frequencies or wavelengths. These absorption characteristics make infrared analyzers an invaluable tool in geoscience, environmental science, and atmospheric science.
Fourier transform infrared spectroscopy (FTIR) [1] is a technique used to obtain an infrared spectrum of absorption or emission of a solid, liquid, or gas. An FTIR spectrometer simultaneously collects high-resolution spectral data over a wide spectral range.