Clausius-Mossotti equation

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A relation between the polarizability α of a molecule and the dielectric constant ε of a dielectric substance made up of molecules with this polarizability. The Clausius-Mossotti equation can be written in the form α = (3/4πN)/[(ε – 1)/(ε – 2)], where N is the number of molecules per unit volume. The equation provides a link between a microscopic quantity (the polarizability) and a macroscopic quantity (the dielectric constant); it was derived using macroscopic electrostatics by the Italian physicist Ottaviano Fabrizio Mossotti (1791–1863) in 1850 and independently by Rudolf Clausius in 1879. It works best for gases and is only approximately true for liquids or solids, particularly if the dielectric constant is large. Compare Lorentz-Lorenz equation.

α = (3/4πN)/[(ε – 1)/(ε – 2)]

Subjects: Chemistry — Physics.

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