X-RAY PHOTOELECTRON STUDY OF TL-BA-CA-CU-O CERAMICS

In this work X-ray photoelectron studies have been carried out for cor e level electron states of thallium, barium, calcium and copper in cup rates Tl2Ba2Ca1Cu2O8+DELTA' Tl2Ba2Ca2Cu3O10+DELTA' their metals and ox ides. It has been found that on going from the oxides to the cuprates Ba4d5/2' Ca2p3/2 electron core levels move to lower binding energies t owards those in the metals and the binding energies of Tl(3+)4f and Cu (2+)2p electrons are close to the corresponding values in the oxides. It is assumed that the fine spectral structure in the energy range 10- 40 eV is connected with interaction of T15d, Ca3p, Ba5p, 5s and O2s sh ells of neighbour atoms with formation of inner valence molecular orbi tals affecting the electron states of outer valence molecular orbitals .