Hard spheres of diameter are particles with the following pairwise interaction potential:

The particle is in a bound state because of the presence of the strong interaction potential.

They are characteristic of the interaction potential between the particles and in general depend on the temperature.

The interaction potential is given as:

DLVO theory describes the interaction potential between charged surfaces.

It is a powerful tool to determine the gas-surface interaction potential by yielding the vibrational energy spectrum of the gas atom bound to the surface.

This field undergoes spontaneous symmetry breaking due to the shape of its interaction potential.

It has also been argued that glass formation in metallic systems is related to the "softness" of the interaction potential between unlike atoms.

The interaction potentials are estimated based on experimental data derived from thermodynamic and mechanical measurements of membrane properties.

Their interaction potential can be written as: