London dispersion force is the weakest of the three van Der Waal forces of interactions universally found in all the atoms and molecules. It is caused by the constant fluctuations in the electron position, creating a temporary dipole. When other nonpolar molecules are in its vicinity, the instantaneous temporary dipole formed earlier distorts the electron cloud of an adjacent molecule, creating another dipole. The ripple effect continues to affect all the molecules in the medium, and they combinedly interact by attraction.
However, these induced dipoles in the molecules are temporary, and the force gets weaker when the distance between molecules increases.
In addition, the London Dispersion Forces are exclusively seen in the nonpolar molecules due to the absence of any other interfering functional groups. In contrast, the other molecules have additional contributing forces (dipole, H-bonding, etc.). The contributing forces make the attractive intermolecular interactions much stronger, requiring more energy to break those bonds than the London Dispersion forces.
This is additional content for the chapter Intermolecular Forces in CurlyArrows' Introduction to Organic Chemistry Course. Preview the Book.
Related Reading:
Introduction to the Vander Waal Forces
