III International Conference

PP-I-81intermediate strength are formed on interaction with NBO – and E' centers (E b = 1.07-1.82 eV).The most weakly silver species interact with neutral oxygen vacancies V O . Calculatedadsorption energies of all considered Ag clusters do not exceed 0.2 eV. It was found thateffect of nucleation of Ag atoms is hindered by strong interaction with defect site. Inparticular, nucleation is calculated to be unfavorable when metal species are bound to V + O andE' centers.According to calculations dimmers Ag 2 are adsorbed in upright orientation. Planerhombic structure of Ag 4 clusters characteristic for that species in gas phase is preserved ininteraction with V O and NBO – defect sites. Adsorption of Ag 4 on V + O site results in distortedrhombic structure with inter-plane angle of 150 o . Interaction with E' center leads to formationof tetrahedral Ag 4 species.This work is supported by SB RAS Integration project N79.References1. Nasluzov V.A., Ivanova E. A., Shor A. M., Birkenheuer U., Rösch N., J. Phys. Chem. B 107(2003) 2228.2. Belling T., Grauschopf T., Krüger S., Mayer M., Nörtemann F., Staufer M., Zenger C., Rösch N.,in High Performance Scientific and Engineering Computing, Lecture Notes in ComputationalScience and Engineering, Vol. 8, Eds. Bundartz H.-J., Durst F., Zenger C., Springer, Heidelberg,1999, p. 439.153