van der Waals force

n.
A weak attractive force between atoms or nonpolar molecules caused by a temporary change in dipole moment arising from a brief shift of orbital electrons to one side of one atom or molecule, creating a similar shift in adjacent atoms or molecules.

[After Johannes Diderik van der Waals (1837-1923), Dutch physicist.]

An attractive force between atoms or molecules, named after Johannes van der Waals (1837–1923). The force accounts for the term a/V ² in van der Waals' equation (see equation of state). These forces are much weaker than those arising from valence bonds and are inversely proportional to the seventh power of the distance between the atoms or molecules. They are the forces responsible for nonideal behaviour of gases and for the lattice energy of molecular crystals. There are three factors causing such forces:

(1) dipole-dipole interaction, i.e. electrostatic attractions between two molecules with permanent dipole moments;
(2) dipole-induced dipole interactions, in which the dipole of one molecule polarizes a neighbouring molecule;
(3) dispersion forces arising because of small instantaneous dipoles in atoms.

---

For more information on van der Waals forces, visit Britannica.com.

The relatively weak, short-range forces of attraction existing between atoms and molecules, which results in the attraction of nonpolar organic compounds to each other (hydrophobic bonding).