Electronic structure and properties of isoelectronic substituted Y1Ba2-mMmCuO3O7 and Y1Ba2-mMmCu4O8 (M = Be, Mg, Ca, Ba, Ra) compounds

According to the data of cluster calculations, electronic structures of isoelectron-substituted in terms of barium compounds on the basis of Y1Ba2Cu3O7 and Y1Ba2Cu4O8 besides certain similarity feature qualitative differences. They are prounced in different character of changes in electronic structure in the course of other element substitution for barium in the two systems mentioned and are related to different nature of both higher occupied and lower free molecular orbits of modelling clusters. 13 refs., 2 figs., 4 tabs