- Hamaker theory
After the explanation of

van der Waals force s byFritz London several scientists soon realised that his definition could be extended from the interaction of twomolecule s with induceddipole s to macro-scale objects by summing all of the forces between themolecule s in each of the bodies involved. The theory is named afterH. 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}" {"i":1,2,... ...,"N"}. The distance between the molecules "i" and "j" is then:: $R\_\{ij\}\; =\; |R\_i\; -\; R\_j|$The interaction energy of the system is taken to be:: $V\_\{mathrm\{int^\{1,2,...N\}\; =\; frac\{1\}\{2\}sum\_\{i=0\}^N\; sum\_\{j=0(\; e\; i)\}^N\; V\_\{mathrm\{int^\{ij\}(R\_\{ij\})$where $V\_\{mathrm\{int^\{ij\}$ 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**

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