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Cross-sections values for all elements with atomic number Z smaller than 100 collected for photons with energies from 1 keV to 20 MeV. The discontinuities in the values are due to absorption edges which were also shown. In physics, absorption cross-section is a measure of the probability of an
Two-photon absorption is a third-order process, with absorption cross section typically several orders of magnitude smaller than one-photon absorption cross section. Two-photon absorption was originally predicted by Maria Goeppert-Mayer in 1931 in her doctoral dissertation. [ 2 ]
The oscillator strength is defined by the following relation to the cross section for absorption: [19] = =, where e {\displaystyle e} is the electron charge, m e {\displaystyle m_{e}} is the electron mass, and ϕ ν {\displaystyle \phi _{\nu }} and ϕ ω {\displaystyle \phi _{\omega }} are normalized distribution functions in frequency and ...
The molar absorption coefficient (in units of M −1 cm −1) is directly related to the attenuation cross section (in units of cm 2) via the Avogadro constant N A: [5] σ = ln ( 10 ) 10 3 N A ε ≈ 3.82353216 × 10 − 21 ε . {\displaystyle \sigma =\ln(10){\frac {10^{3}}{N_{\text{A}}}}\varepsilon \approx 3.82353216\times 10^{-21 ...
The mass attenuation coefficient (also called "mass extinction coefficient"), which is the absorption coefficient divided by density; The absorption cross section and scattering cross-section, related closely to the absorption and attenuation coefficients, respectively "Extinction" in astronomy, which is equivalent to the attenuation coefficient
In physics, the cross section is a measure of the probability that a specific process will take place in a collision of two particles. For example, the Rutherford cross-section is a measure of probability that an alpha particle will be deflected by a given angle during an interaction with an atomic nucleus.
The absorption neutron cross section of an isotope of a chemical element is the effective cross-sectional area that an atom of that isotope presents to absorption and is a measure of the probability of neutron capture. It is usually measured in barns. Absorption cross section is often highly dependent on neutron energy. In general, the ...
The Kramers–Heisenberg dispersion formula is an expression for the cross section for scattering of a photon by an atomic electron.It was derived before the advent of quantum mechanics by Hendrik Kramers and Werner Heisenberg in 1925, [1] based on the correspondence principle applied to the classical dispersion formula for light.