Calculation of electronic structure of YBa2Cu3O7-δ in LCAO MO approximation

On the basis of calculation by CNDO methods study of copper oxidation degree and valence, oxygen bond character, instability of charge states, their causes is carried out. An attempt of studying electron state density in YBa2Cu3O7-δ compound and also electron behaviour near Fermi surface depending on oxygen and copper atoms state is made using cluster calculations. It is supposed that at 0.5 < δ < 1 in YBa2Cu3O7-δ copper atoms are in a state close to 3d10 state, therewith oxygen atoms are in a state close to 0-1 one