Condensed Matter Physics, 2015, vol. 18, No. 2, 24601
Gas-liquid critical point of the ultrasoft restricted primitive model from analytic theory
(Institute for Condensed Matter Physics of the National
Academy of Sciences of Ukraine, 1 Svientsitskii St., 79011 Lviv,
Gas-liquid criticality in the ultrasoft restricted primitive model (URPM) of polyelectrolytes is studied using the collective
variables-based theory. For the model, an effective Hamiltonian is derived and explicit expressions for all the coefficients are
found in a one-loop approximation. Based on this Hamiltonian, the phase and critical behaviour is analysed.
Our results provide evidence that the nature of the gas-liquid criticality in the URPM is the same as in the restricted primitive
model that includes a hard core.
polyelectrolytes, ultrasoft restricted primitive model, gas-liquid critical point, effective Hamiltonian
64.75.-g, 64.60.De, 64.75.Cd, 64.60.fd