Van der Waals force
= Van der Waals force
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The Van der Waals force is a distance-dependent nonbonded interaction between atoms or molecules, including dispersion and dipolar contributions. In the attractive nonretarded pair model, an interaction energy $U(r)=-\beta/r^6$ gives force magnitude $6\beta/r^7$. Macroscopic integration introduces a <Hamaker constant>; it does not replace the sign change and molecular cutoff needed at very short distances.