Permittivity of vacuum

The permittivity of a vacuum, sometimes called the permittivity of empty space by electrical engineers, is denoted and expressed in F.mIt is defined by Coulomb s law in a vacuum. The modulus of the electrostatic force, expressed in newtons (N), between two point electric charges in a vacuum or q, expressed in coulombs (C), separated by a distance in meters (m), is given by the following equation  

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In isotropic media 0 and S are related by = < , where the scalar parameter a is now referred to as the permittivity. In the international (SI) system it is given by s = erso. where o is the permittivity of vacuum (see Appendix fl) and e, is a dimensionless permittivity that characterizes the medium. Furthermore, according to Ohm s law the current is given by 7 = cr< , where a is the electrical conductivity. The relation V S3 = 0 is a mathematical statement of the observation that isolated magnetic poles do not exist. 

Here, e0 is the permittivity of vacuum, sel the dielectric constant of the electrolyte, z is the valency of the ions in the electrolyte, and I represents the ionic strength, which for a 1 1 salt, can be replaced by the electrolyte concentration n0. 

Here the atoms in the system are numbered by i, j, k, l = 1,..., N. The distance between two atoms i, j is ry, q is the (partial) charge on an atom, 6 is the angle defined by the coordinates (i, j, k) of three consecutive atoms, and 4> is the dihedral angle defined by the positions of four consecutive atoms, e0 is the dielectric permittivity of vacuum, n is the dihedral multiplicity. The potential function, as given in equation (6), has many parameters that depend on the atoms involved. The first term accounts for Coulombic interactions. The second term is the Lennard-Jones interaction energy. It is composed of a strongly repulsive term and a van der Waals-like attractive term. The form of the repulsive term is chosen ad hoc and has the function of defining the size of the atom. The Ay coefficients are a function of the van der Waals radii of the... 

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