Berlin 2015 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 5: Plasmonics: Nanoantennas, Nanoparticles

O 5.10: Vortrag

Montag, 16. März 2015, 12:45–13:00, MA 042

Nanoscale noble metal clusters: First principles atomistic time-dependent density functional calculations — •Mikael Kuisma and Paul Erhart — Applied Physics, Chalmers University of Technology, Sweden

Nanoscale plasmonics has a variety of potential applications from cancer treatment to renewable energy. At these length scales a quantum mechanical treatment is required in order to obtain a reliable representation of the plasmonic response.

We have developed and implemented an efficient basis set based real-time propagation method in the GPAW code. The method is used together with the time-dependent GLLB-SC potential and applied to nanoscale noble metal clusters. For the first time, systems with over 10,000 valence electrons are available in ab initio all-electron time-dependent density functional (TDDFT) calculations with moderate computational effort. Using this approach we simulate the optical spectra of icosahedral silver clusters Ag ranging from 55 to 561 atoms (1.06–2.68 nm). We observe that localized surface plasmon resonances enter the asymptotic region already at diameters between 1-2 nm, converging to the classical quasistatic limit of 3.4 eV. We show that proper description of both d-band position and bandwidth is crucial.

As a further demonstration of the practicality of our method, we establish the nature of plasmonic response in palladium hydride nanoclusters. To this end, we combine the absorption spectra of hundreds of large palladium clusters with varying hydrogen content.