Hard sphere model

Interaction Potential

The hard sphere interaction potential is given by

$V\left(r\right)=\left\{{\begin{array}{lll}\infty &;&r<\sigma \\0&;&r\geq \sigma \end{array}}\right.$

where $V\left(r\right)$ is the potential energy between two spheres at a distance $r$, and $\sigma$ is the diameter of the sphere.

Equations of state

Hard sphere fluid:

1. See Carnahan-Starling (three dimensions)
2. See Ref.1

Hard sphere solid:

1. See Ref. 2

Related systems

Hard disks in a 2-dimensional space

Hard rods in one dimension

Widom-Rowlinson model

Polydisperse hard spheres

Data

Virial coefficients of hard spheres and hard disks are to be found in the table.

Experimental results

For results obtained from the Colloidal Disorder - Order Transition (CDOT) experiments performed on-board the Space Shuttles Columbia and Discovery see Ref. 3.

References

1. Robin J. Speedy "Pressure of the metastable hard-sphere fluid", Journal of Physics: Condensed Matter 9 pp. 8591-8599 (1997)
2. Robin J. Speedy "Pressure and entropy of hard-sphere crystals", Journal of Physics: Condensed Matter 10 pp. 4387-4391 (1998)
3. Z. Chenga, P. M. Chaikina, W. B. Russelb, W. V. Meyerc, J. Zhub, R. B. Rogersc and R. H. Ottewilld, "Phase diagram of hard spheres", Materials & Design 22 pp. 529-534 (2001)