How do you explain what a Van der Waals force is?
Molecules without dipole moments exist in the liquid and solid states under certain conditions. Thus, they exert forces on each other.
The forces that exist among noble gas atoms and nonpolar molecules are called London dispersion forces (L.D.F.) or Van der Waals forces.
Consider a pair of noble gas atoms. As electrons move around the nucleus, a momentary nonsymmetrical distribution of charge will result in producing a temporary dipolar arrangement of charge. This, in turn, will affect the distribution of charge in the neighboring atom. This means that an instantaneous dipole will induce a similar dipole in the neighboring atom as seen in the figures below.