Electric Dipoles and their Physics

An electric Dipole is made up of two equal and opposite point charges also known as poles. The electric dipoles are characterized by their electric dipole moment. The dipole moment is a physical quantity with magnitude equal to the product of the magnitude of either charge and the distance between the charges. As the dipole moment is a vector quantity, its direction is from negative charge towards the positive charge.

A theoretical magnetic dipole has a magnetic field of exactly the same form as the electric field of an electric point dipole. A very small current-carrying loop is approximately a magnetic point dipole; the magnetic dipole moment of such a loop is the product of the current flowing in the loop and the (vector) area of the loop.

Any configuration of charges or currents has a 'dipole moment', which describes the dipole whose field is the best approximation, at large distances, to that of the given configuration.

There are such molecules which have dipole moments due to non-uniform distributions of positive and negative charges on the various atoms. Similar is the situation in polar compounds like Hydrogen Fluoride, where charge density is shared unequally between different atoms. Therefore, a molecule's dipole is an electric dipole with an inherent electric field that should not be confused with a magnetic dipole that generates a magnetic field.

The molecular dipoles were first studied by a physical chemist Peter J W Debye. There are 03 types of dipoles for molecules

1. Permanent Dipoles which occur when two atoms in a molecule have substantially different electronegativity.

2. Instantaneous dipoles which occur due to chance when electrons happen to be more concentrated in one place than another inside a molecule thereby creating a temporary dipole.

3. Induced dipoles which occur when one molecule with a permanent dipole repels another molecule's electrons, causing an induction of dipole moment in that molecule.