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While the London dispersion force between individual atoms and molecules is quite weak and decreases quickly with separation like , in condensed matter (liquids and solids), the effect is cumulative over the volume of materials, [6] or within and between organic molecules, such that London dispersion forces can be quite strong in bulk solid and ...
However, in larger molecules dispersion effects can become significant. Dispersion forces in molecular chemistry are most apparent in molecules with large, bulky functional groups. [1] Dispersion stabilization is often signified by atomic contacts below their van der Waals radii in a molecule's crystal structure.
London dispersion forces are also known as 'dispersion forces', 'London forces', or 'instantaneous dipole–induced dipole forces'. The strength of London dispersion forces is proportional to the polarizability of the molecule, which in turn depends on the total number of electrons and the area over which they are spread.
Non-covalent interactions can be classified into different categories, such as electrostatic, π-effects, van der Waals forces, and hydrophobic effects. [3] [2] Non-covalent interactions [4] are critical in maintaining the three-dimensional structure of large molecules, such as proteins and nucleic acids.
The third and dominant contribution is the dispersion or London force (fluctuating dipole–induced dipole), which arises due to the non-zero instantaneous dipole moments of all atoms and molecules. Such polarization can be induced either by a polar molecule or by the repulsion of negatively charged electron clouds in non-polar molecules.
The source of adhesive forces, according to the dispersive adhesion mechanism, is the weak interactions that occur between molecules close together. [2] These interactions include London dispersion forces, Keesom forces, Debye forces and hydrogen bonds. Individually, these attractions are not very strong, but when summed over the bulk of a ...
Fritz Wolfgang London (March 7, 1900 – March 30, 1954) was a German born physicist and professor at Duke University.His fundamental contributions to the theories of chemical bonding and of intermolecular forces (London dispersion forces) are today considered classic and are discussed in standard textbooks of physical chemistry.
Lifshitz's theory for two metal plates reduces to Casimir's idealized 1 / a 4 force law for large separations a much greater than the skin depth of the metal, and conversely reduces to the 1 / a 3 force law of the London dispersion force (with a coefficient called a Hamaker constant) for small a, with a more complicated ...