title: Atomistic electrodynamics simulations of bare and ligand-coated nanoparticles in the quantum size regime.
abstract: The optical properties of metallic nanoparticles with nanometre dimensions exhibit features that cannot be described by classical electrodynamics. In this quantum size regime, the near-field properties are significantly modified and depend strongly on the geometric arrangements. However, simulating realistically sized systems while retaining the atomistic description remains computationally intractable for fully quantum mechanical approaches. Here we introduce an atomistic electrodynamics model where the traditional description of nanoparticles in terms of a macroscopic homogenous dielectric constant is replaced by an atomic representation with dielectric properties that depend on the local chemical environment. This model provides a unified description of bare and ligand-coated nanoparticles, as well as strongly interacting nanoparticle dimer systems. The non-local screening owing to an inhomogeneous ligand layer is shown to drastically modify the near-field properties. This will be important to consider in optimization of plasmonic nanostructures for near-field spectroscopy and sensing applications.
authors.affiliation: Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, 16802, Pennsylvania, USA.
authors.forename: Xing
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, 16802, Pennsylvania, USA.
authors.forename: Justin E
authors.initials: JE
authors.lastname: Moore
authors.affiliation: Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, 16802, Pennsylvania, USA.|Present address: School of Chemistry and Biochemistry, The Georgia Institute of Technology, 2201 Molecular Science and Engineering Building, Atlanta, Georgia 30332, USA.
authors.forename: Meserret
authors.initials: M
authors.lastname: Zekarias
authors.affiliation: Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, 16802, Pennsylvania, USA. jensen@chem.psu.edu.
authors.forename: Lasse
authors.initials: L
authors.lastname: Jensen