Quantum chemical study of structural, linear, and nonlinear optical response of pure silver clusters Agn (n = 2–10)

Abstract

In this study, pure silver clusters Agn (n = 2–10) through a density functional method is explored to analyze the structure-property relationship with the linear and nonlinear optical response. The total density of state (TDOS), photoelectron spectra (PES) and non-covalent interaction (NCI) analyses are also performed to get structural information regarding the bonding environment. New energy levels developed as the silver atoms in higher clusters which are indicated by lowering the HOMO energy level. Among these clusters, Ag5 and Ag9 showed unusual behaviour with higher first hyperpolarizability values (1076 and 2223 au, respectively). The results of hyperpolarizability are compared with the external reference molecule para-nitroaniline (p-NA). Additionally, a two-level model has been applied to rationalize the first hyperpolarizability. The primary outcomes of this study enable the scientist to use silver clusters for photovoltaic applications or as a dopant to enhance the nonlinear optical response.