Keesomkrachten

Keesomkrachten, also known as London dispersion forces or instantaneous dipole-induced dipole forces, are weak, short-range intermolecular forces that arise from the temporary fluctuations of electron distribution within molecules. All molecules, regardless of polarity, experience these forces.

The Keesomkracht originates from the spontaneous movement of electrons within an atom or molecule. At any given moment, the electron distribution might be uneven, creating a temporary, instantaneous dipole. This instantaneous dipole can then induce a temporary dipole in a neighboring molecule by attracting or repelling its electrons. The attraction between these temporary, induced dipoles constitutes the Keesomkracht.

These forces are generally much weaker than permanent dipole-dipole interactions or hydrogen bonds, but they become significant when the molecules are close together. The strength of Keesomkrachten increases with the size and number of electrons in a molecule, as larger electron clouds are more easily distorted. They play a crucial role in phenomena such as the liquefaction of nonpolar gases and the adhesion of surfaces.