Engineering Physics

6.4 Clausius–Mosotti relation

Clausius–Mosotti relation makes relation between microscopic and macroscopic quantities of polarization. A dielectric material can be polarized by applying an external field on it. Dipole moment per unit volume of material is called polarization. The dipole moment ‘p’ is equal to the product of one of the charges and separation between the opposite charges of atoms or molecules. This dipole moment is proportional to the local electric field, E_loc, so that:

p = αE_loc _____ (6.15)

where ‘α’ is the electrical polarizability. If there are ‘n’ atoms per unit volume of the dielectric, then polarization ‘P’ is:

P = np = nαE_loc _____ (6.16)

Substituting the equation for local electric field, E_loc = E + P/3∈₀ in the above ...