Gaussian overlap model

The Gaussian overlap model was developed by Bruce J. Berne and Philip Pechukas and is given by Eq. 3 in the aforementioned reference:

${\mathrm{\Phi }}_{12}({\mathbf{u}}_1,{\mathbf{u}}_2,\mathbf{r})=ϵ({\mathbf{u}}_1,{\mathbf{u}}_2)\exp {[\frac{-r}{\sigma ({\mathbf{u}}_1,{\mathbf{u}}_2,\hat{\mathbf{r}})}]}^n$

where $n=2$, ${\mathrm{\Phi }}_{12}(r)$ is the intermolecular pair potential, $ϵ({\mathbf{u}}_1,{\mathbf{u}}_2)$ and $\sigma ({\mathbf{u}}_1,{\mathbf{u}}_2,\hat{\mathbf{r}})$ are angle dependent strength and range parameters, and $\hat{\mathbf{r}}$ is a unit vector. Not long after the introduction of the Gaussian overlap model Stillinger proposed a stripped-down version of the model, known as the Gaussian core model. Note that as $n\to \mathrm{\infty }$ this potential becomes the penetrable sphere model.

Equation of state

Main article: Equations of state for the Gaussian overlap model

Virial coefficients

Main article: Gaussian overlap model: virial coefficients

Phase diagram

The phase diagram of the Gaussian-core model has been calculated by Prestipino et al. while the solid-liquid phase equilibria has been calculated by Mausbach et al using the GWTS algorithm.

References

Related reading

• P. A. Monson and K. E. Gubbins "Equilibrium properties of the Gaussian overlap fluid. Monte Carlo simulation and thermodynamic perturbation theory" Journal of Physical Chemistry 87 pp. 2852-2858 (1983)
• Tomas Boublik "The gaussian overlap model again", Molecular Physics 67 pp. 1327-1336 (1989)