Cross Section (physics) - Scattering

Scattering

The scattering cross-section, σscat, is a hypothetical area which describes the likelihood of light (or other radiation) being scattered by a particle. In general, the scattering cross-section is different from the geometrical cross-section of a particle, and it depends upon the wavelength of light and the permittivity, shape and size of the particle. The total amount of scattering in a sparse medium is determined by the product of the scattering cross-section and the number of particles present. In terms of area, the total cross-section (σ) is the sum of the cross-sections due to absorption, scattering and luminescence

The total cross-section is related to the absorbance of the light intensity through Beer-Lambert's law, which says absorbance is proportional to concentration:, where C is the concentration as a number density, Aλ is the absorbance at a given wavelength λ, and is the path length. The extinction or absorbance of the radiation is the logarithm (decadic or, more usually, natural) of the reciprocal of the transmittance:

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Famous quotes containing the word scattering:

    Or of the garden where we first mislaid
    Simplicity of wish and will, forgetting
    Out of what cognate splendor all things came
    To take their scattering names;
    Richard Wilbur (b. 1921)

    What was he doing, the great god Pan,
    Down in the reeds by the river?
    Spreading ruin and scattering ban,
    Splashing and paddling with hoofs of a goat,
    And breaking the golden lilies afloat
    With the dragon-fly on the river.
    Elizabeth Barrett Browning (1806–1861)

    And Time, a maniac scattering dust,
    And Life, a Fury slinging flame.
    Alfred Tennyson (1809–1892)