Effective interactions and charge ordering in the model with local anharmonicity for HTSC systems

Pseudospin-electron model (used for the description of high-Tc superconducting systems) including strong electron correlations and interaction with local anharmonic vibrations is investigated. It was shown that in mean field approximation (MFA) the pseudospin-electron interaction further the transition to charge ordered state. The calculation of the '' transversal '' dielectric susceptibility χ perpendicular (q,ω) within the generalized random phase approximation in the method of Matsubara's Green functions is performed. The possibility of the dielectric instability and instability with respect to charge ordering is shown; the influence of the anomalies of Χ perpendicular on the superconducting pairing of electrons is discussed