The binding of an adsorbate to the surface of a solid by forces whose energy levels approximate those of condensation. Contrast with chemisorption.

Physisorptionhttp://www.iupac.org/goldbook/P04667.pdf IUPAC Gold Book definition of physical adsorption or physical adsorption is a type of adsorption in which the adsorbate adheres to the surface only through Van der Waals force (weak intermolecular) interactions, the same that are responsible for the imperfection of real gases and the condensation of vapors.