Electrostatic forces only exist between molecules with permanent moments of their charge distribution. Molecules do not have to distort or fluctuate in order to exhibit electrostatic intermolecular forces. Intermolecular forces are longest-ranged (act strongly over a large distance) when they are electrostatic.

COULOMB'S LAW : The scalar form of Coulomb's law is an expression for the magnitude and sign of the electrostatic force between two idealised point charges, small in size compared to their separation. This force (F) acting simultaneously on point charges (q₁) and (q₂), is given by

F=kq₁q₂/r²

where r is the separation distance and k is a proportionality constant. A positive force implies it is repulsive, while a negative force implies it is attractive. The proportionality constant k, called the coulomb constant (sometimes called the coulomb force constant), Coulomb's law holds even within the atoms, correctly describing the force between the positively charged nucleus and each of the negatively charged electrons. This simple law also correctly accounts for the forces that bind atoms together to form molecules and for the forces that bind atoms and molecules together to form solids and liquids.

The electrostatic interaction between two charges is given by coulombs law, where q_i, q_j are the partial atomic charges, k is the effective dielectric constant and rij is the relative distance between the two particles.

F=kq_iq_j/r²

The electrical potential energy for m no of molecules interacting with n no of molecules is given by

U=∑_i^mkqQ/r