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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.
The absorption spectrum is primarily determined [2] [3] [4] by the atomic and molecular composition of the material. Radiation is more likely to be absorbed at frequencies that match the energy difference between two quantum mechanical states of the molecules .
The zero-phonon line is an optical analogy to the Mössbauer lines, which originate in the recoil-free emission or absorption of gamma rays from the nuclei of atoms bound in a solid matrix. In the case of the optical zero-phonon line, the position of the chromophore is the physical parameter that may be perturbed, whereas in the gamma ...
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]
The plot for vapor is a transformation of data Synthetic spectrum for gas mixture ' Pure H 2 O ' (296K, 1 atm) retrieved from Hitran on the Web Information System. [6] Liquid water absorption spectrum across a wide wavelength range [missing source] The absorption of electromagnetic radiation by water depends on the state of the water.
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).
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 ...
The oscillator strength for any transition between ground and excited state depends on these coefficients. The absorption cross-section (σ λ) is empirically determined from this oscillator strength and the broadening of the absorption/emission line by collisions, the Doppler effect and the uncertainty principle.