Coil-torus transition

Prom the condition F = 0 we obtain the coil-torus transition line... 

To predict the coil-torus and torus-globule transition lines we have to make an ansatz for the excess free energy of the collapsed states with respect to the coil state ... 

By substituting the equilibrium torus radii (5.41) to Eq. (5.40), we obtain the expression for the equilibrium value of the globular free energy, from which it can be seen that upon heating the toroidal globule transforms into the coil state, the corresponding phase transition being of the first order. For the temperature and the heat of the transition we obtain... 

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