Density-functional studies of plasmons in small metal clusters.

Area of Science:

• * Computational Nanoscience
• * Materials Science
• * Quantum Chemistry

Background:

• * Understanding plasmon modes in metallic nanoparticles is crucial for applications in optics and electronics.
• * Gold clusters exhibit unique electronic and optical properties influenced by their size and atomic composition.
• * The role of d-electrons in plasmon formation within small gold clusters requires detailed theoretical investigation.

Purpose of the Study:

• * To model and analyze the formation of plasmon modes in small gold clusters.
• * To investigate the influence of cluster size on the longitudinal plasmon mode.
• * To elucidate the effect of d-electrons on the excitation spectra and identify transverse modes.

Main Methods:

• * Utilized time-dependent Kohn-Sham (TD-KS) theory for electronic structure calculations.
• * Employed Gaussian basis sets for accurate atomic orbital representation.
• * Applied a frozen-orbital approximation to aid in the identification of specific plasmon modes.

Main Results:

• * Observed that the shape of the longitudinal plasmon mode changes with cluster size.
• * Determined that d-electrons in gold significantly impact plasmon formation, leading to high excitation energies for transverse modes.
• * Characterized complex excitation spectra profiles due to d-electron involvement.

Conclusions:

• * The electronic structure of gold, particularly the d-electrons, plays a critical role in determining plasmonic properties of small clusters.
• * The study successfully modeled plasmon mode formation and size-dependent spectral changes.
• * The frozen-orbital approximation proved effective in identifying transverse plasmon modes within the complex spectra.