Title: THE ELECTRON SPECTRUM AND THE EFFECTIVE EXCHANGE INTERACTION FOR MULLER MODEL IN THE THEORY OF HTSC
Author(s): I.V.Stasyuk, A.M.Shvaika

The self-consistent calculations of the single-electron exitation spectrum within Hubbard-I approximation and invectigation of the electron effective exchange interaction are performed for the Hubbard model including the interaction with local anharmonic vibrations (Muller model). The approach based on the exact solution of the single-site problem is used. In contrast to the Hubbard model, the obtained spectrum has an additional subbands. The interaction with vibrational subsystem (described by pseudospin variables) leads to the destruction of the electron-hole symmetry and the existance of hole conductivity at half filling. On the contrary to the t-J-model, the electron exchange interaction is not constant and can be antiferromagnetic or ferromagnetic dependent on the pseudospin subsystem state. The electron exchange couplings are fructrated when the vibrational subsystem is non-equilibrium.