Polarization

In dielectric solid most of the electrons are bound to the nuclear When an external E field is applied→centroid of electronic cloud is displaced from the centroid of the nucleus→dipole is created and atom is said to be polarized.

Types of polarization #

• Electronic polarization
• Ionic polarization
• Orientational/Dipolar polarization
• Space charge polarization

Clausius Mossotti’s equation #

It can be derived using: #

$$ \begin{align} P=N\alpha E_{int}\\ \\ P=\frac{E}{\epsilon-\epsilon_0} \\ Lorentz\\ field\\ eq: E_{int}=E+\frac{P}{3\epsilon_0}\\ \\ \epsilon/\epsilon_0 = \epsilon_r \end{align} $$

P: total polarization α: polarizability

The equation #

$$ \frac{N\alpha}{3\epsilon _0}=\frac{\epsilon_r-1}{\epsilon_r+2} $$