Hamaker theory

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:

${\displaystyle R_{ij}=|R_{i}-R_{j}|}$

The interaction energy of the system is taken to be:

${\displaystyle V_{\mathrm {int} }^{1,2,...N}={\frac {1}{2}}\sum _{i=0}^{\mathbb {N} }\sum _{j=0(\neq i)}^{\mathbb {N} }V_{\mathrm {int} }^{ij}(R_{ij})}$

where ${\displaystyle V_{\mathrm {int} }^{ij}}$ is the interaction of molecules i and j in the absence of the influence of other molecules.