Size dependence of the static polarizabilities and absorption spectra of Agn (n=2-8) clusters -: art. no. 085445

Static polarizabilities and optical absorption spectra of ground state structures of Ag-n clusters (n=2-8) are investigated from first principles within static and time-dependent density functional theory. The static polarizabilities of the clusters with less than 7 atoms exhibit even-odd oscillations. The polarizabilities of Ag-7 and Ag-8 are very close and noticeably lower. This change in the behavior of the static polarizability is correlated with the transition from two-dimensional to three-dimensional structures at n=7. The optical spectra calculated within the time-dependent local density approximation indicate sharp excitations in the 3-5 eV region. These are associated mainly with s electrons, although d electrons also affect the spectra by quenching the oscillator strengths through screening of the s electrons and by getting partially involved in the excitations. The calculated optical spectra are in good agreement with the available experimental data and results from earlier theoretical studies.