Date of Award

2009

Publication Type

Doctoral Thesis

Degree Name

Ph.D.

Department

Physics

Keywords

Physics, Condensed Matter.

Supervisor

Aroca, Ricardo (Chemistry & Biochemistry)

Rights

info:eu-repo/semantics/openAccess

Abstract

Metallic nanoparticles, in particular silver and gold nanostructures, are at the centre of the development of plasmon enhanced optical signals. There is a flurry of activities in the fabrication and testing of these nanostructures, especially in surface enhanced Raman scattering (SERS) and surface enhanced-infrared absorption (SEIRA), the two branches of surface-enhanced vibrational spectroscopy. The need to develop an understanding of this general subject matter for practicing spectroscopists cannot be questioned. This work is a unique undertaking intended to examine some of the elements that give rise to surface enhanced spectroscopy. The optical properties of nanoparticles are discussed in detail, beginning with a discussion of the electromagnetic theory describing the interaction of light and matter. Exact solutions to the electromagnetic equations are used to model and calculate plasmonics of nanoparticles. These methods include Mie theory, and extensions to Mie such as for concentric spheres and interacting spheres. Approximate methods are also discussed, such as the dipolar model for ellipsoids of rotation, and the coupled dipole equations for irregular or interacting particles. These models are used to obtain optical properties as well as enhanced electromagnetic fields, applied to surface enhanced vibrational spectroscopy. The origin of vibrational spectroscopy is briefly described, and quantum mechanical calculations are performed to describe a variety of the molecular possibilities arising through surface enhanced spectroscopy, such as aggregation, chemical adsorption, and surface selection rules.

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