Density functional study of polarons and bipolarons in polar liquids

The density functional theory of polarons and bipolarons in a polar liquid is presented. Starting from the grand partition function, we have developed a microscopic model and derived the free-energy functional of the system in which the electrons are treated within the Kohn-Sham formalism, while the solvent via the integral equations theory. The case of our approach concerns with the free-energy functional corresponding to the mean spherical approximation and the extended point dipole model. We have calculated different properties for a polaron and a singlet bipolaron formation and their variations caused by changes in temperature, density, and polarity of the solvent. The obtained results are in agreement with available experimental data and simulations.