Abstract
This chapter focuses on the use of the semiempirical intermediate neglect of differential overlap Hamiltonian together with a configuration interaction (INDO/CI) treatment of optical excited states to study the optical properties of bare silver nanoclusters and silver nanoclusters with adsorbed pyridine molecules. It establishes a baseline comparison between INDO/CI and time‐dependent density functional theory by studying small silver clusters such as tetrahedral Ag
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. To capture the effects of a plasmonic material on an adsorbed molecule, the chapter examines the cases of a tetrahedral Ag
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cluster with a pyridine molecule adsorbed on either a vertex or a face of the tetrahedron in the absence of an applied potential. It also examines the effects of an applied potential on the surface‐enhanced Raman spectroscopy spectra by utilizing the same orbital energy shift approximation that are used to study the charge‐transfer states and the geometry dependence of the formal potential.