Ramp model: Difference between revisions
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The ''' | The '''ramp model''' is described by: | ||
:<math> | :<math> | ||
\Phi(r) = \left\{ | |||
\begin{array}{ll} | \begin{array}{ll} | ||
\infty & {\rm if} \; r < \sigma \\ | \infty & {\rm if} \; r < \sigma \\ | ||
Line 11: | Line 11: | ||
</math> | </math> | ||
where <math>W_r > 0</math> and <math>W_a < 0</math>. | where <math>\Phi(r)</math> is the [[intermolecular pair potential]], <math>W_r > 0</math> and <math>W_a < 0</math>. | ||
Graphically, one has: | Graphically, one has: |
Revision as of 13:57, 21 June 2007
The ramp model is described by:
where is the intermolecular pair potential, and .
Graphically, one has:
where the red line represents an attractive implementation of the model, and the green line a repulsive implementation.
References
- P. C. Hemmer and G. Stell "Fluids with Several Phase Transitions", Physical Review Letters 24 pp. 1284 - 1287 (1970)
- G. Stell and P. C. Hemmer, "Phase Transitions Due to Softness of the Potential Core", Journal of Chemical Physics' 56, pp. 4274-4286 (1972)
- E. A. Jagla "Core-softened potentials and the anomalous properties of water", Journal of Chemical Physics' 111, pp. 8980-8986 (1999)
- E. Lomba, N. G. Almarza, C. Martin, C. McBride "Phase behaviour of attractive and repulsive ramp fluids: integral equation and computer simulation studies" arxiv.org/abs/cond-mat/0703509