After the explanation of

van der Waals force In molecular physics, the van der Waals force is a distance-dependent interaction between atoms or molecules. Unlike ionic or covalent bonds, these attractions do not result from a chemical electronic bond; they are comparatively weak and ...

s by

Fritz London Fritz Wolfgang London (March 7, 1900 – March 30, 1954) was a German physicist and professor at Duke University. His fundamental contributions to the theories of chemical bonding and of intermolecular forces ( London dispersion forces) are today ...

, several scientists soon realised that his definition could be extended from the interaction of two

molecule A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and b ...

s with induced

dipole In physics, a dipole () is an electromagnetic phenomenon which occurs in two ways: *An electric dipole deals with the separation of the positive and negative electric charges found in any electromagnetic system. A simple example of this system ...

s to macro-scale objects by summing all of the forces between the

s in each of the bodies involved. The theory is named after H. C. Hamaker, who derived the interaction between two spheres, a sphere and a wall, and presented a general discussion in a heavily cited 1937 paper.Hamaker, H. C. (1937) The London – van der Waals attraction between spherical particles. ''Physica'' 4(''10''), 1058–1072. The interaction of two bodies is then treated as the pairwise interaction of a set of ''N'' molecules at positions: ''R_i'' . The distance between the molecules ''i'' and ''j'' is then: :

R_ = , R_i - R_j,

The interaction energy of the system is taken to be: :

V_^ = \frac\sum_^\N \sum_^\N V_^(R_)

where

V_^

is the interaction of molecules ''i'' and ''j'' in the absence of the influence of other molecules. The theory is however only an approximation which assumes that the interactions can be treated independently, the theory must also be adjusted to take into account quantum perturbation theory.

References

Physical chemistry Intermolecular forces {{chemistry-stub