sentences:  It is commonly assumed that the surface force between two atomic planes at a distance formula_48 from each other can be derived from the Lennard-Jones potential.With this assumption
  where formula_4 is the force (positive in compression), formula_164 is the total surface energy of "both" surfaces per unit area, and formula_165 is the equilibrium separation of the two atomic planes.The Bradley model applied the Lennard-Jones potential to find the force of adhesion between two rigid spheres.