absorption spectrum
Quick Summary
An absorption spectrum is a pattern of dark lines or bands within an electromagnetic spectrum, indicating specific wavelengths of radiation that have been absorbed by a substance. This phenomenon is a key aspect of spectral methods in chemical analysis.12
In absorptiometry, a technique within spectral methods, instruments measure how much electromagnetic radiation is absorbed by a substance, known as the analyte. This absorption occurs when a photon of radiation strikes a molecule, exciting it to a higher energy state. The intensity of the radiation decreases as it passes through the sample, and this decrease is measured.2
Different substances absorb radiation at unique wavelengths, making absorption spectra useful for identifying specific elements or molecules. This principle is applied in various forms of spectroscopy, including infrared and ultraviolet-visible spectrophotometry, to analyze molecular vibrations and electronic transitions.342
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- spectroscopyHistorical survey
…collectively referred to as an absorption spectrum. The spectra of materials that were heated in flames or placed in electric-gas discharges were studied by many scientists during the 18th and 19th centuries. These spectra were composed of numerous bright discrete lines, indicating that only certain wavelengths were present in the…
Read More…collectively referred to as an absorption spectrum. The spectra of materials that were heated in flames or placed in electric-gas discharges were studied by many scientists during the 18th and 19th centuries. These spectra were composed of numerous bright discrete lines, indicating that only certain wavelengths were present in the…
Read More - spectroscopyGeneral methods of spectroscopy
…on a dark background, or absorption spectra, which have a continuously bright background except for one or more dark lines.
Read More…on a dark background, or absorption spectra, which have a continuously bright background except for one or more dark lines.
Read More - spectroscopyElectronic transitions
…the inverse of a visible absorption spectrum. The underlying phenomenon is that of an electron being raised from a low-energy molecular orbital (MO) to one of higher energy, where the energy difference is given as ΔE = hν. For a collection of molecules that are in a particular MO or…
Read More…the inverse of a visible absorption spectrum. The underlying phenomenon is that of an electron being raised from a low-energy molecular orbital (MO) to one of higher energy, where the energy difference is given as ΔE = hν. For a collection of molecules that are in a particular MO or…
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