Entropic sampling of the flexible polyelectrolyte with the Wang-Landau algorithm

We consider a flexible polyelectrolyte model on a lattice. The Coulomb potential and the excluded volume condition between different ions/beads are taken into account. We use the entropic sampling method implemented within an efficient numerical algorithm presented by Wang and Landau in 2001 to study thermodynamic properties of the system. The obtained energy distributions provide the calculation of canonical properties such as conformational energy, heat capacity, entropy, and free energy by numerical integration. Entropic sampling with the Wang-Landau algorithm allows us to obtain statistics for the states with extremely low probabilities of realization in the statistical ensemble, down to $10^{(-285)}$. We also compare the results of entropic sampling with the data obtained by the standard Monte Carlo method.