Van Der Waals Forces

Name:
Van Der Waals Forces
Detailed information:
(London dispersion force). Weak attractive forces acting between molecules. They are somewhat weaker than hydrogen bonds and far weaker than interatomic valences. They are involved in the van der Waals equation of state for gases, which compensates for the actual volume of the molecules and the forces acting between them. “Information regarding the numerical values of van der Waals forces is mostly semiempirical, derived with the aid of theory from an analysis of chemical or physical data. Attempts to calculate the forces from first principles have had a measure of success only for the simplest systems, such as H—H, He—He and a few others. When judging the difficulties of such calculations, one must bear in mind that the energies sought are of the same order of magnitude as those in the best atomic energy calculations.” (Henry Margenau).See Hydrogen Bond; Bond, Chemical.