Dynamics and thermodynamics of the pseudospin-electron model in the case   of absence of the electron Hubbard correlation. I. The analytical   consideration
  Dynamics and thermodynamics of the model with local anharmonism in the case of absence of the electron (Hubbard) correlation is investigated in the present work. The correlation functions, mean values of pseudospin and particle number as well as the thermodynamical potential are calculated. The calculation is performed by diagrammatic method in the mean field approximation. Single--particle Green functions are taken in the Hubbard--I approximation. 
I.V.Stasyuk, A.M.Shvaika, K.V.Tabunschyk