Absorption spectra of small silver clusters Agn (n = 4, 6, 8): A TDDFT study

The absorption spectra of Agn (n = 4, 6, 8) clusters are studied in the framework of the time-dependent density functional theory (TDDFT) and related techniques employing relativistic effective core potential. For investigating the influence of structural properties on the absorption spectra, the transition energies and oscillator strengths of the stable structure and the isomeric forms are investigated. The absorption spectra of the Ag clusters with varying bond lengths and fixed symmetry are also inspected. A small blueshift is found on the dominant peak with decreasing bond length, which is consistent with the experimental work. For Agn (n = 4, 6, 8) clusters with the same symmetry, a small redshift (∼0.4 eV) appears on the dominant peak with decreasing n. The transfer of s-electron is mainly responsible for the absorption spectra. While the transfer of d-electron is not negligible.