The IMF molecules are linked by Van der Waals forces, which are permanent but dipole-dipole junctions.
If the interactions are molecules that are permanently polarized (for example, water molecules that attract other water molecules or other polar molecules), they are found as Keesom forces.
London dispersion forces, dipole-dipole forces and hydrogen bonds are secondary weak forces that exist between molecules. For it to be called a molecule, it shows tha the bond present is a covalent bond. The covalent bond arises from the shaing of electrons between the atoms.
A typical example is the hydrogen molecule, H2. Both hydrogen atoms share the two electrons which signifies a covalent bond.
