Modeling and measuring plasmonic excitations in hollow spherical gold nanoparticles

Abstract

We investigate molecular plasmonic excitations sustained in hollow spherical gold nanoparticles using time-dependent density functional theory (TD-DFT). Specifically, we consider Au60 spherical, hollow molecules as a toy model for single-shell plasmonic molecules. To quantify the plasmonic character of the excitations obtained from TD-DFT, the energy-based plasmonicity index is generalized to the framework of DFT, validated on simple systems such as the sodium Na20 chain and the silver Ag20 compound, and subsequently successfully applied to more complex molecules. We also compare the quantum mechanical TD-DFT simulations to those obtained from a classical Mie theory that relies on macroscopic electrodynamics to model the light–matter interaction. This comparison allows us to distinguish those features that can be explained classically from those that require a quantum-mechanical treatment. Finally, a double-shell system obtained by placing a C60 buckyball inside the hollow spherical gold particle is further considered. It is found that the double-shell, while increasing the overall plasmonic character of the excitations, leads to significantly lowered absorption cross sections.

TURBOMOLE: Today and Tomorrow

“…Damped polarizabilities and the related magnetizabilities have further emerged as the quantum-chemical cornerstone of the transition matrix (T-matrix) based approach for multiscale modeling of light–matter interactions. ,, This way, the functionalization of molecular structures within optical devices is possible. In that regard, optical cavities filled with molecular materials or metasurfaces of cylinders consisting of molecular materials can be designed.…”