Symbol α. A measure of the response of a molecule to an external electric field. When a molecule is placed in an external electric field, the displacement of electric charge induces a dipole in the molecule. If the electric field strength is denoted E and the electrical dipole moment induced by this electric field p, the polarizability α is defined by p = αE. To calculate the polarizability from first principles it is necessary to use the quantum mechanics of molecules. However, if regarded as a parameter, the polarizability α provides a link between microscopic and macroscopic theories as in the Clausius-Mossotti equation and the Lorentz-Lorenz equation.
p = αE
Subjects: Chemistry — Physics.