Electrical permittivity, relative

Since water has a high dielectric constant of 80 (electric permittivity relative to a vacuum), the energy associated with an ion pair in a protein ranges from 0.5 to 1.5 kJ moT for a surface interaction and up to 15 kJ moT for an electrostatic interaction between residues that are buried in the interior of a protein, where the dielectric constant is low. 

Here, and 6 are specific electric permittance, relative permittivity of moisture and thickness of the Stern layer. Permittivity of hydrated and orderly moisture near the interface is noticeably lower that relative permittivity of moisture and ranges between 6 and 50 (Hayes et al, 1991). Usually the value 10 is used. 

The two dielectric constants in Eq. [6] warrant some discussion. The quantity e, which is sometimes called simply the dielectric constant (often denoted e instead of e ) is more precisely the static or zero-frequency dielectric constant. (Even more precisely, it is the scalar electric permittivity relative to that of vacuum, and is therefore dimensionless.) This quantity includes the effects of both orientational and electronic polarization. For a vertical ionization process, however, the solvent s orientational degrees of freedom are frozen, but the electron densities of individual solvent molecules can adjust on the same timescale on which the ionization process occurs. Such considerations lead to a correction involving the optical (infinite-frequency) dielectric constant, where denotes the solvent s index of refraction. 

The dielectric constant of a polymer (K) (which we also refer to as relative electric permittivity or electric inductive capacity) is a measure of its interaction with an electrical field in which it is placed. It is inversely related to volume resistivity. The dielectric constant depends strongly on the polarizability of molecules tvithin the polymer. In polymers with negligible dipole moments, the dielectric constant is low and it is essentially independent of temperature and the frequency of an alternating electric field. Polymers with polar constituents have higher dielectric constants. When we place such polymers in an electrical field, their dipoles attempt... 

Thus, we see the initial connection between optical properties and the electrical and magnetic properties from the two previous sections. Substimtion of Eqs. (6.78) and (6.79) into (6.77) shows that the refractive index can be expressed in terms of the relative electric permittivity (dielectric constant), (cf. Table 6.5), and relative magnetic permeability of the medium, (1 - - x) [cf. Eq. (6.63)], where x is the magnetic susceptibility ... 

The capacitance of the Helmholtz parallel plate capacitor per surface unit is given by Ch = e o/d, where er is the dielectric constant or the relative electric permittivity of the Hemholtz layer and e0 the electrical permittivity of free space (sq = 8.854 x 1CT12 C2 J 1 nr1) [3, 4]. 

Molecular distortion polarizability is a measure of the ease with which atomic nuclei within molecules tend to be displaced from their zero-field positions by the applied electric field. (3) Orientation polarizability is a measure of the ease with which dipolar molecules tend to align against the applied electric field. The electron polarizability of an individual molecule is related to the -> permittivity (relative) of a dielectric medium by the -> Clausius-Mossotti relation. 

Electrical conductivity, relative permittivity (dielectric constant)... 

In the absence of a strong dectric fidd (at = 0), the measured relative electric permittivity of an isotropic dielectric is a scalar quantity, defined as follows ... 

Molar Electric Polarization of Dense Media.— In Kirkwood s semi-macroscopic treatment of the linear proparties of isotropic dielectrics, one has the following relation between the relative electric permittivity Sr and the polarization P( ) induced in the medium ... 

It should be noticed that, in many theoretical works, the term solvent polarity is defined by the values of the relative electric permittivity, also called dielectric constant. However, such a definition is by no means precise. The existence of hydrogen bonds (H-bonds) between solute and solvent molecules is one of the important limitations of the use of the continuum models based on the theory of dielectrics. In modern physical chemistry of solutions in order to quantitatively describe the solvatochromism phenomenon various empirical scales of the polarity are used. The exhaustive reviews on this topic have been presented by Reichardt [1, 2],... 

The present research aims to develop a type of element permitting electric field relaxation, consisting of constituent materials graded for electric permittivity. The constituents used are titamium oxide and kaolin. 15 combinations of titamium oxide and kaolin in differing relative proportions were produced by a vacuum filter prcess, and tests were conducted to measure the permittivity and conductivity of each. 

If to expand hyperbolic cosine (ch) in equation (2.133) into Taylor series and to leave only the first term of the series equal to 1, then we get a relatively simple expression for the determination of electric permittance density of the diffuse layer... 

We report on the determination of the complete tensor of relative electric permittivity in single crystals of pTS, as a function of temperature and polymer contents. Since the dielectric measurements prove to be a suitable method, enabling one to follow the second- order phase transition in pTS, we compare the dielectric behavior of monomer and polymer of pTS and pFBS, looking for a possible signature of a phase transition in the latter crystals. 

This expression illustrates the dependence of each factor (for a given ) on two quantities only, the relative electric permittivity and the shape of the cavity, represented here by its radius. 

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