The Fermi-Jagla model is a smooth variant of the Jagla model. It is given by (Eq. 1 in [1]):
![{\displaystyle \Phi _{12}(r)=\epsilon _{0}\left[\left({\frac {a}{r}}\right)^{n}+{\frac {A_{0}}{1+\exp \left[{\frac {A_{1}}{A_{0}}}{\frac {r}{a-A_{2}}}\right]}}-{\frac {B_{0}}{1+\exp \left[{\frac {B_{1}}{B_{0}}}{\frac {r}{a-B_{2}}}\right]}}\right]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/e44449caa9a8f37cb2ead06142358c54adcf6a79)
There is a relation between Fermi function and hyperbolic tangent:

Using this relation one can show that Fermi-Jagla model is equivalent to Fomin potential introduced earlier.
References
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