Polarizability's the relative tendency of a charge distribution, like the electron cloud of an atom or molecule, to be distorted from its normal shape by an external electric field, which may be caused by the presence of a nearby ion or dipole. The electronic polarizability alpha's defined as the ratio of the induced dipole moment oldsymbol. In this case alpha's described as a tensor of rank 2, which's represented with respect to a given system of axes (frame of reference) by a 3 imes3 matrix.… (More on Polarizability)