Harmonic repulsion potential

The Harmonic repulsion potential is given by ( Eq. 2):

${\mathrm{\Phi }}_{12}(r)=\{\begin{array}{ccc}\frac{ϵ}{2}(1-r/\sigma {)}^2& ;& r<\sigma \\ 0& ;& r\ge \sigma \end{array}$

where ${\mathrm{\Phi }}_{12}(r)$ is the intermolecular pair potential, $r:=|{\mathbf{r}}_1-{\mathbf{r}}_2|$ is the distance between site 1 and site 2. $\sigma$ represents a length scale and $ϵ$ an energy. For example, for $ϵ=20$ the potential looks like

Phase diagram

The phase diagram in the pressure-temperature plane has been calculated by Zhu and Lu .

See also

• Hertzian sphere model