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London dispersion forces (LDF, also known as dispersion forces, London forces, instantaneous dipole–induced dipole forces, fluctuating induced dipole bonds [1] or loosely as van der Waals forces) are a type of intermolecular force acting between atoms and molecules that are normally electrically symmetric; that is, the electrons are ...
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.
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.
The dispersion (London) force is the most important component because all materials are polarizable, whereas Keesom and Debye forces require permanent dipoles. The London interaction is universal and is present in atom-atom interactions as well. For various reasons, London interactions (dispersion) have been considered relevant for interactions ...
Dispersion forces keep the molecule inert even while its core Si-Si bond lengthens. Similarly, the longest known Ge-Ge bond is found in t Bu 3 GeGe t Bu 3 and is also facilitated by dispersion stabilization. [19] Dispersion stabilization has also been invoked for (t BuC) 3 P, a main group analog of a hydrocarbon tetrahedrane. [20]
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 ...
After the explanation of van der Waals forces by Fritz London, several scientists soon realised that his definition could be extended from the interaction of two molecules with induced dipoles to macro-scale objects by summing all of the forces between the molecules in each of the bodies involved.
[19] [20] [21] All atoms and molecules can partake in van der Waals and London dispersion forces . It is the lack or presence of other intermolecular interactions based on the atom or molecule that affords materials unique properties. [19]