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Infrared spectroscopy (IR spectroscopy or vibrational spectroscopy) is the measurement of the interaction of infrared radiation with matter by absorption, emission, or reflection. It is used to study and identify chemical substances or functional groups in solid, liquid, or gaseous forms.
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.
It states that no normal modes can be both Infrared and Raman active in a molecule that possesses a center of symmetry. This is a powerful application of group theory to vibrational spectroscopy, and allows one to easily detect the presence of this symmetry element by comparison of the IR and Raman spectra generated by the same molecule. [1]
As in other infrared spectroscopy, the molecules in the sample are excited to a higher energy state due to the absorption of infrared (IR) radiation emitted from the IR source in the instrument, which results in vibrations of molecular bonds. The intrinsic physicochemical property of each particular molecule determines its corresponding IR ...
Near-infrared spectroscopy is, therefore, not a particularly sensitive technique, but it can be very useful in probing bulk material with little to no sample preparation. The molecular overtone and combination bands seen in the near-IR are typically very broad, leading to complex spectra; it can be difficult to assign specific features to ...
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 Fourier transform with respect to provides the excitation spectrum (frequency ). 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 ...
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.