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  2. Absorption spectroscopy - Wikipedia

    en.wikipedia.org/wiki/Absorption_spectroscopy

    The most straightforward approach to absorption spectroscopy is to generate radiation with a source, measure a reference spectrum of that radiation with a detector and then re-measure the sample spectrum after placing the material of interest in between the source and detector. The two measured spectra can then be combined to determine the ...

  3. Emission spectrum - Wikipedia

    en.wikipedia.org/wiki/Emission_spectrum

    The emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to electrons making a transition from a high energy state to a lower energy state. The photon energy of the emitted photons is equal to the energy difference between the two states. There are many possible ...

  4. Atomic absorption spectroscopy - Wikipedia

    en.wikipedia.org/wiki/Atomic_absorption_spectroscopy

    Atomic absorption spectroscopy (AAS) is a spectroanalytical procedure for the quantitative measurement of chemical elements. AAS is based on the absorption of light by free metallic ions that have been atomized from a sample. An alternative technique is atomic emission spectroscopy (AES).

  5. Spectroscopy - Wikipedia

    en.wikipedia.org/wiki/Spectroscopy

    Absorption is often determined by measuring the fraction of energy transmitted through the material, with absorption decreasing the transmitted portion. Emission spectroscopy: Emission indicates that radiative energy is released by the material. A material's blackbody spectrum is a

  6. Stokes shift - Wikipedia

    en.wikipedia.org/wiki/Stokes_shift

    Diagram of the Stokes shift between absorption and emission light spectra. Stokes shift is the difference (in energy, wavenumber or frequency units) between positions of the band maxima of the absorption and emission spectra (fluorescence and Raman being two examples) of the same electronic transition. [1]

  7. Spectral line - Wikipedia

    en.wikipedia.org/wiki/Spectral_line

    A spectral line may be observed either as an emission line or an absorption line. Which type of line is observed depends on the type of material and its temperature relative to another emission source. An absorption line is produced when photons from a hot, broad spectrum source pass through a cooler material.

  8. Atomic spectroscopy - Wikipedia

    en.wikipedia.org/wiki/Atomic_spectroscopy

    In optical spectroscopy, energy absorbed to move an electron to a higher energy level (higher orbital) and/or the energy emitted as the electron moves to a lower energy level is absorbed or emitted in the form of photons (light particles). Because each element has a unique number of electrons, an atom will absorb/release energy in a pattern ...

  9. Einstein coefficients - Wikipedia

    en.wikipedia.org/wiki/Einstein_coefficients

    An emission line is formed when an atom or molecule makes a transition from a particular discrete energy level E 2 of an atom, to a lower energy level E 1, emitting a photon of a particular energy and wavelength. A spectrum of many such photons will show an emission spike at the wavelength associated with these photons.