What is "van der waals force"

n. (context chemistry often in plural English) The relatively weak attraction between neutral atoms and molecules arising from polarization induced in each particle by the presence of other particles.

In physical chemistry, the van der Waals' forces (or van der Waals' interaction), named after Dutch scientist Johannes Diderik van der Waals, are the residual attractive or repulsive forces between molecules or atomic groups that do not arise from a covalent bond, or electrostatic interaction of ions or of ionic groups with one another or with neutral molecules. The resulting van der Waals forces can be attractive or repulsive.

The term includes:

• force between permanent dipoles ( Keesom force)
• force between a permanent dipole and a corresponding induced dipole ( Debye force)
• force between instantaneously induced dipoles ( London dispersion force).

It is also sometimes used loosely as a synonym for the totality of intermolecular forces. Van der Waals forces are relatively weak compared to covalent bonds, but play a fundamental role in fields as diverse as supramolecular chemistry, structural biology, polymer science, nanotechnology, surface science, and condensed matter physics. Van der Waals forces define many properties of organic compounds, including their solubility in polar and non-polar media.

In low molecular weight alcohols, the hydrogen-bonding properties of the polar hydroxyl group dominate other weaker van der Waals interactions. In higher molecular weight alcohols, the properties of the nonpolar hydrocarbon chain(s) dominate and define the solubility. Van der Waals forces quickly vanish at longer distances between interacting molecules.