= Hamaker estimate of liquid surface tension
{c}
{title2=$\gamma\simeq A_H/(24\pi h_0^2)$}
For two liquid half-spaces, integrate the magnitude of a dispersion attraction per area $A_H/(6\pi h^3)$ from a molecular contact cutoff $h_0$ to infinity. The work per area is $A_H/(12\pi h_0^2)$. Because cleavage creates two interfaces, each has the displayed <surface tension> in this approximation. The cutoff is essential: a continuum attraction cannot describe atomic overlap and short-range repulsion. This estimate neglects interfacial entropy, detailed density profiles and nonadditive interactions, and it cannot replace the <metallic bonding> or <hydrogen bonds> that dominate some liquids' cohesion.
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