Multiscale Modeling of Broadband Perfect Absorbers Based on Gold Metallic Molecules.

The modeling of functional photonic devices that rely on molecular materials continues to be a major contemporary challenge. It is a challenge because, in the Maxwell equations, which govern the light-matter interaction, material properties are primarily introduced on phenomenological grounds and not from first principles. To overcome such limitations, we outline a multiscale modeling approach that bridges multiple length scales.

Modeling and measuring plasmonic excitations in hollow spherical gold nanoparticles.

We investigate molecular plasmonic excitations sustained in hollow spherical gold nanoparticles using time-dependent density functional theory (TD-DFT). Specifically, we consider Au 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 Na chain and the silver Ag compound, and subsequently successfully applied to more complex molecules.