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The relative permittivity (in older texts, dielectric constant) is the permittivity of a material expressed as a ratio with the electric permittivity of a vacuum. A dielectric is an insulating material, and the dielectric constant of an insulator measures the ability of the insulator to store electric energy in an electrical field.
The Bjerrum length (after Danish chemist Niels Bjerrum 1879–1958 [1]) is the separation at which the electrostatic interaction between two elementary charges is comparable in magnitude to the thermal energy scale, , where is the Boltzmann constant and is the absolute temperature in kelvins.
Another common term encountered for both absolute and relative permittivity is the dielectric constant which has been deprecated in physics and engineering [3] as well as in chemistry. [ 4 ] By definition, a perfect vacuum has a relative permittivity of exactly 1 whereas at standard temperature and pressure , air has a relative permittivity of ...
Two types of PCMs have been popularly used: the dielectric PCM (D-PCM), in which the continuum is polarizable (see dielectrics), and the conductor-like PCM (C-PCM), in which the continuum is conductor-like, similar to the COSMO Solvation Model. [1] [2] The molecular free energy of solvation is computed as the sum of three terms: G sol = G es ...
The Born equation can be used for estimating the electrostatic component of Gibbs free energy of solvation of an ion. It is an electrostatic model that treats the solvent as a continuous dielectric medium (it is thus one member of a class of methods known as continuum solvation methods). It was derived by Max Born. [1] [2]
PCB warning label on a power transformer known to contain PCBs. Polychlorinated biphenyls (PCBs) are organochlorine compounds with the formula C 12 H 10−x Cl x; they were once widely used in the manufacture of carbonless copy paper, as heat transfer fluids, and as dielectric and coolant fluids for electrical equipment. [2]
where () is the reference chemical potential, T the absolute temperature, and k the Boltzmann constant. The reference chemical potential can be eliminated by applying the same equation far away from the surface where the potential is assumed to vanish and concentrations attain the bulk concentration c B. The concentration profiles thus become
A method comparison [7] of COSMO and the integral equation formalism PCM (IEFPCM), which combines the exact dielectric boundary conditions with a reduced outlying charge error, showed that the differences between the methods are small as compared to deviations to experimental solvation data. The errors introduced by treating a solvent as a ...