Structural and optical properties of small oxygen-doped- and pure-silver clusters

Abstract

We present calculations of absorption patterns in large energy intervals for the stable structures of oxygen-doped-and pure-silver clusters using the linear-response-type approach which allows one to correlate all 11 and 6 electrons per Ag and O atoms, respectively. For this purpose, we designed a new 11-electron relativistic effective core potential (11e-RECP) for Ag atoms at the correlated level of theory, which, together with the associated AO basis set, provide an accurate description of excited states. This has been evidenced by the comparison of our results with available experimental data. We found that inclusion of d electrons in the RECP, as well as in the correlation treatment, is important for an accurate prediction of the complete absorption spectra. Moreover, the influence of d electrons of Ag atoms becomes pronounced, even for structural properties of Agn O clusters. Also, the electrons of oxygen are strongly involved in excitations besides those of Ag-valence electrons, leading to intense transitions spread in a large energy interval. The role O plays in Agn O clusters differs substantially from the one it plays in oxygen-doped alkali clusters, because of the participation of the d electrons of Ag atoms.