Quantum entrapment and valence charge polarization in Ag, Cu, Pt, and Rh nanoclusters

Abstract

Atomic under-coordination and non-bonding electrons are extensively used in nanomaterials and nanostructures. The bonds between the under-coordinated sites follow the rule of relaxation dynamics, although quantum confinement (QC) theory, Coulomb blockade, and size-dependent dynamic effects cannot describe the change in Hamiltonian and other magnitudes. The effect of under-coordinated atom on the electronic structures of nanomaterials was calculated in this study using the bond-orderlength-strength (BOLS) correlation and non-bonding electron polarization (NEP) notations. The Hamiltonian perturbation of the atomic under-coordination entrapped the core electrons and polarized the valence charge. Consistency between the BOLS-NEP notation and density functional theory (DFT) calculations on Ag, Cu, Pt, and Rh nanoclusters with cuboctahedral (COh) and Marks decahedral (M-Dh) structures confirmed that the shorter and stronger bonds between atomic under-coordination induced local densification, quantum entrapment, and valence charge polarization. The strong localization determined the intriguing catalytic, magnetic, and plasmonic attributes of these metallic nanoclusters. The effect of excess charge states from (+2) to (-2) was determined using DFT calculations and BOLS correlation theories on the metallic nanoclusters with COh and M-Dh structures. Consistency between DFT calculations and experimental observations confirmed our BOLS predictions including the local bond length relaxation, charge investigated using excess charge states, including negative, neutral, and positive charges Chapter 1: Introduction 3 on the surface in both theoretical and experimental observations. 25-27 The excess charge states on the nanocluster surface play a significant role in the ability of catalysts in adjusting oxide support. Bond-order-length-strength (BOLS) correlation 28 has been used to refine the nonbonding electron polarization (NEP) theory, 3, 29, 30 to solve associated problems, 31, 32 including superfluidity in carbon nanotube channels, 33 superlubricity in dry sliding, 31, 34 and supersolidity of 4 He with superelasticity and superfluidity. 35 The effect of undercoordinated atoms and excess charge states on Ag, Cu, Pt, and Rh metallic nanoclusters are investigated in this study according to the BOLS-NEP theory. According to unique properties of these metallic nanoclusters such as magnetic and nonmagnetic order, and plasmon and catalyst applications, we are chosen Ag, Cu, Pt, and Rh metallic nanoclusters in this thesis. In addition, the results of Ag, Cu, Pt, and Rh metallic nanoclusters are presented separately, in Chapters 4 and 5, respectively, because Ag, Cu, Pt, and Rh belong to different elements such as Nobel and open metals. 1.2 Challenges The concept of broken bonds and non-bonding in nanomaterials is complicated. According to theoretical and experimental observations, valence band polarization, CLS, lattice strain, charge transfer, magnetization, optical application, and electronic properties of metallic nanoclusters ar...