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Polarizability is responsible for a material's dielectric constant and, at high (optical) frequencies, its refractive index. The polarizability of an atom or molecule is defined as the ratio of its induced dipole moment to the local electric field; in a crystalline solid, one considers the dipole moment per unit cell. [1]
The polarizability of individual particles in the medium can be related to the average susceptibility and polarization density by the Clausius–Mossotti relation. In general, the susceptibility is a function of the frequency ω of the applied field.
However, care is needed because some authors [6] take out the factor from (), so that = and hence () = /, which is convenient because then the (hyper-)polarizability may be accurately called the (nonlinear-)susceptibility per molecule, but at the same time inconvenient because of the inconsistency with the usual linear polarisability definition ...
In many materials the polarizability starts to saturate at high values of electric field. This saturation can be modelled by a nonlinear susceptibility. These susceptibilities are important in nonlinear optics and lead to effects such as second-harmonic generation (such as used to convert infrared light into visible light, in green laser pointers).
In electromagnetism, the absolute permittivity, often simply called permittivity and denoted by the Greek letter ε , is a measure of the electric polarizability of a dielectric material. A material with high permittivity polarizes more in response to an applied electric field than a material with low permittivity, thereby storing more energy ...
Molar refractivity, [1] [2], is a measure of the total polarizability of a mole of a substance. For a perfect dielectric which is made of one type of molecule, the molar refractivity is proportional to the polarizability of a single molecule of the substance. For real materials, intermolecular interactions (the effect of the induced dipole ...
2 He helium-4; Hoffer et al. 0.19085 g/cm 3 (from 20.9730 cm 3 /mole; hcp crystal melting to He-II superfluid at 0 K, 25.00 atm) : 0.19083 g/cm 3 (from 20.9749 cm 3 /mole; at local min. density, hcp melting to He-II: 0.884 K, 25.00 atm)
Saturate, Aromatic, Resin and Asphaltene (SARA) is an analysis method that divides crude oil components according to their polarizability and polarity. The saturate fraction consists of nonpolar material including linear, branched, and cyclic saturated hydrocarbons ( paraffins ).