Physical Sciences and Mathematics Commons^™

Theoretical Study Of Localized Surface Plasmons Of Metal Nanoparticles, Clusters And Embedded Metal Nanoparticles In Matrices, Masoud Shabani Nezhad Navrood

Dissertations

Localized surface plasmons resonances (LSPRs) in metallic nanoparticles (NPs) arise from the interactions between incident light and conduction electrons and have attracted enormous research interest in recent years both for their fundamental nature as well as applications in interdisciplinary areas of sciences such as biological imaging, plasmonic photo-thermal therapy, photovoltaics, and plasmonic sensors. LSPRs are strongly localized and depend on the shape, size, the composition of the NPs, the polarization direction of the incident light, refractive index (RI) of the surrounding medium as well as on the chemical environment that surrounded NPs. Although significant research has progressed both theoretically and …

Photoionization Of Rare Gas Clusters, Huaizhen Zhang

Dissertations

This thesis concentrates on the study of photoionization of van der Waals clusters with different cluster sizes. The goal of the experimental investigation is to understand the electronic structure of van der Waals clusters and the electronic dynamics. These studies are fundamental to understand the interaction between UV-X rays and clusters. The experiments were performed at the Advanced Light Source at Lawrence Berkeley National Laboratory. The experimental method employs angle-resolved time-of-flight photoelectron spectrometry, one of the most powerful methods for probing the electronic structure of atoms, molecules, clusters and solids.

The van der Waals cluster photoionization studies are focused on …

Entanglement Perturbation Theory For Antiferromagnetic Spin Chains, Lihua Wang

Dissertations

In this dissertation, we use the recently developed Entanglement Perturbation Theory (EPT) to solve antiferromagnetic spin chain problems, for both spin 1/2 and spin 1. We firs use EPT-g (EPT algorithm for ground state) to get the ground state properties. We calculated precisely energies, magnetization and spin-spin correlations. The precision of the long range spin-spin correlation functions for spin 1/2 chains is unprecedented. Due to its special structure, we also use EPT-g to calculate the firs excited state properties for spin 1 chains. Hence we plotted the phase diagram for spin 1 xxz chains. Also a generalization of EPT (EPT-e) …

Transmission And Guiding Of Fast Electrons Through Insulating Nanocapillaries And Comparison With Ion Guiding, Susanta Das

Dissertations

Transmission and guiding of fast electrons (500 and 1000 eV) through an insulating polyethylene terephthalate nanocapillary foil has been investigated and compared with results for slow highly charged ions. As for slow ions, guiding is attributed to charge-up of the inner walls near the capillary entrance, which, after a characteristic time, electrostatically deflects the traversing ions causing them to be guided through the sample along the capillary axis. The measurements were performed at WMU. Electron guiding is found to decrease faster with both energy and foil tilt angle than for ions. Ions lose negligible energy during the course of guiding, …