Theoretical studies of the electromagnetic response of metal nanoparticles

• Main Author: Xuan, Fengyuan
• Other Authors: Claude Guet
• Format: Theses and Dissertations
• Language: English
• Published: 2017
• Subjects: DRNTU::Science::Physics::Optics and light; DRNTU::Science::Physics::Atomic physics::Quantum theory
• Online Access: http://hdl.handle.net/10356/69938
• Institution: Nanyang Technological University

My PhD project aims at developing a set of theoretical models to explain the electromagnetic response of metal nanoparticles, ranging from sub-nanometer to hundreds of nanometers and bulk. Simple metals such as sodium and lithium serve to define the zeroth order approximation. The next step will be to consider particular role of d-electrons in noble metal and how it can be modeled while keeping the optical response driven fully by delocalized valence electrons. We introduce a modified Random Phase Approximation with exact Exchange. The jellium background of Ag cores is treated as a polarizable sphere, which screens the dipole component of the electron-electron interaction. Our model gives the blue shift as cluster size decreases for cationic Ag clusters which agrees well with experimental data. For clusters embedded in rare-gas matrix, we propose a similar polarization screening model. The dipole surface resonance peak is shifted to lower energy significantly.