Electric and Magnetic Susceptibilities

Abstract

Abstract This chapter begins by discussing the effects of an electric field. An external electric field, E, will exert a force on all the charged constituents of a material. This force results in a displacement of various charge centres that, in equilibrium and in an insulator, is balanced by fields induced by the displacements themselves; at finite frequencies one must also account for the inertia (mass) associated with the accelerated nuclei and electrons making up the system, ultimately in a manner consistent with quantum mechanics. Such charge displacements in the body produce dipole moments. To account for the effect of these dipoles one introduces a polarization, defined as the dipole moment per unit volume. The electric field also produces a force on all the electrons. The strong nuclear electric field tightly constrains the motion of the core electrons; their orbitals are nonetheless distorted by the external field resulting in a core contribution to the electronic polarization. The remainder of the chapter deals with static ionic polarizibility; the electronic polarizibility of atoms and molecules; and the magnetic susceptibility of atoms and molecules.

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Affiliated Institutions

• Northwestern University US

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