Optical Properties of Silver and Gold Nanoparticles

In two recent papers, researchers from Trieste and Pisa studied the optical properties of silver and gold nanoparticles.

The fundamental study on silver nanoshells showed that plasmonic features emerge at shells as small as 92 atoms. Furthermore, the hollow shells are red-shifted with respect to compact nanoparicles, the absorption maximum red-shifts with system size, and icosahedral shells show a stronger absorption at higher energy.

Gold adamantanethiol clusters were synthesized and isolated at the University of Mississippi and studied theoretically by the two Italian groups. The bulky ligands created structural flexibility of the gold nano-core. The calculated spectra for these complexes are in good agreement with experimental findings.

Mauro Stener and Oscar Baseggio are working on an even more efficient TDDFT algorithm in ADF to enable the calculation of the optical properties of much larger nanoparticles.

Relativistic TDDFT (SR-ZORA) calculations on Au₂₄(SAdm)₁₆ (left, in good agreement with experiment) and on icosahedral Ag₂₅₄⁴⁺ monatomic nanoshell (right)

D. Crasto, G. Barcaro, M. Stener, L. Sementa, A. Fortunelli, and A. Dass, Au₂₄(SAdm)₁₆ Nanomolecules: X‑ray Crystal Structure, Theoretical Analysis, Adaptability of Adamantane Ligands to Form Au₂₃(SAdm)₁₆ and Au₂₅(SAdm)₁₆, and Its Relation to Au₂₅(SR)₁₈,  J. Am. Chem. Soc., 136, 14933-14940 (2014)

G. Barcaro, L. Sementa, A. Fortunelli, and M. Stener, Optical Properties of Silver Nanoshells from Time-Dependent Density Functional Theory Calculations,  J. Phys. Chem. C, 118, 12450-12458 (2014)