A model of a transition metal adatom chemisorption on ionic crystals, which is modelled by a semi-infinite chain of alternating A-B atoms, is studied. The Anderson-News approach is adopted to take account of the Coulomb repulsion between the d-orbital electrons of the adatom. Using self-consistent Green's function method, the chemisorption energies and transfer of adatom charge are calculated for different values of the couplilng constant between d-orbital electrons of adatom and surface of ionic crystal Some interesting qualitative conclusions are obtained by discussing the existence conditions and properties of various self-consistent solutions.