Abstract
Pseudopotential time-dependent density-functional theory (TDDFT) calculations are carried out to investigate the optical absorption spectra of magic-number noble-metal nanoparticles of 13, 38, 55, 140, and 147 atoms. In particular, we study the differences between isomeric structures such as Ag in both cubic and icosahedral structures. Differences are well visible up to sizes of about 55 atoms, demonstrating the need for proper treatment of the structural details on the atomic level. For the largest sizes of about 150 atoms, our calculations confirm earlier results of TDDFT using a structureless jellium model. In particular, we recover the surface plasmon resonance for silver nanoclusters. The bimetallic AgAu core-shell cluster displays an intense peak corresponding to the surface-plasmon resonance in the Ag cluster, but the spectrum does not lie between the spectra of the pure Ag and Au clusters. By contrast, a copper core in a AgCu cluster leads to a strong damping of this peak.
- Received 30 April 2011
DOI:https://doi.org/10.1103/PhysRevB.84.165443
©2011 American Physical Society