Back مطيافية الامتصاص Arabic Apsorpcijska spektroskopija BS Espectroscòpia d'absorció Catalan Espectroscopia de absorción Spanish Xurgaketa-espektroskopia Basque طیف‌بینی جذبی Persian Spectrométrie d'absorption French Speictreascópacht ionsúcháin Irish Apsorpcijska spektroskopija Croatian Կլանման սպեկտրալ գիծ Armenian

Absorption spectroscopy

An overview of electromagnetic radiation absorption. This example discusses the general principle using visible light. A white beam source – emitting light of multiple wavelengths – is focused on a sample (the complementary color pairs are indicated by the yellow dotted lines). Upon striking the sample, photons that match the energy gap of the molecules present (green light in this example) are absorbed in order to excite the molecule. Other photons transmit unaffected and, if the radiation is in the visible region (400–700 nm), the sample color is the complementary color of the absorbed light. By comparing the attenuation of the transmitted light with the incident, an absorption spectrum can be obtained.
The first direct detection and chemical analysis of the atmosphere of an exoplanet, in 2001. Sodium in the atmosphere filters the starlight of HD 209458 as the giant planet passes in front of the star.

Absorption spectroscopy is spectroscopy that involves techniques that measure the absorption of electromagnetic radiation, as a function of frequency or wavelength, due to its interaction with a sample. The sample absorbs energy, i.e., photons, from the radiating field. The intensity of the absorption varies as a function of frequency, and this variation is the absorption spectrum. Absorption spectroscopy is performed across the electromagnetic spectrum.

Absorption spectroscopy is employed as an analytical chemistry tool to determine the presence of a particular substance in a sample and, in many cases, to quantify the amount of the substance present. Infrared and ultraviolet–visible spectroscopy are particularly common in analytical applications. Absorption spectroscopy is also employed in studies of molecular and atomic physics, astronomical spectroscopy and remote sensing.

There is a wide range of experimental approaches for measuring absorption spectra. The most common arrangement is to direct a generated beam of radiation at a sample and detect the intensity of the radiation that passes through it. The transmitted energy can be used to calculate the absorption. The source, sample arrangement and detection technique vary significantly depending on the frequency range and the purpose of the experiment.

Following are the major types of absorption spectroscopy:[1]

Sr. No Electromagnetic radiation Spectroscopic type
1 X-ray X-ray absorption spectroscopy
2 Ultraviolet–visible UV–vis absorption spectroscopy
3 Infrared IR absorption spectroscopy
4 Microwave Microwave absorption spectroscopy
5 Radio wave Electron spin resonance spectroscopy

Nuclear magnetic resonance spectroscopy

  1. ^ Kumar, Pranav (2018). Fundamentals and Techniques of Biophysics and Molecular biology. New Delhi: Pathfinder publication. p. 33. ISBN 978-93-80473-15-4.

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