powercat.jpgSurface Optical Properties of Gold Nanoparticles

        by Emily K. Walker

        Supervisors:  Dr. Law and Dr. Sorensen

Kansas State University Physics Department  REU Program, sponsored by NSF

Welcome to my webpage.  This page summarizes my experience doing research for summer 2008 with Dr. Bruce Law and Dr. Chris Sorensen.

Below, I describe the Project Goals, my Research Strategy, my Research Progress, and have posted my Final Presentation .I post my homework assignments from our weekly REU scientific Ethics class, taught by Prof. Bruce Glymour and Prof. Amy Lara, and my reaction to Prof. Larry Weaver's Lectures.   Scroll down to learn more About Me. I have added some photos from my summer in Kansas. Finally, I've included some Useful Links.

Project Goals:  My goal is to determine some of the optical properties of gold nanoparticles. I hope to find out whether they form a layer on the bottom of the sample holder, or if all the changes are caused by a bulk effect. To do this I will vary the concentration of the nanoparticle solution.

Research Strategy:  I will collect data using an ellipsometer and varying concentrations of gold nanoparticle solution to determine the optical properties of gold nanoparticles. I am trying to determine whether the particles remain in solution at high concentrations, or if they fall to the bottom and create a layer. To determine which the case is, I am using Python script to model the different situations and comparing my data to those models. The nanoparticles are about 5 nm in diameter and are suspended in a solution of tert-butyl toluene (tbt). Attached to these nanoparticles are ligands which prevent the nanoparticles from clustering and increase their size to ~7.4 nm. A schematic of my set-up can be found here. The ellipsometer measures ρ, the ratio between the p and s directions of the polarization of the reflected light off the substance. The p direction is that parallel to the surface, and the s is perpendicular.

Final PresentationClick here to download my presentation in PowerPoint.


About Me:  I am currently a rising junior physics major/optical engineering minor at Rose-Hulman Institute of Technology. I am on the RHIT women’s lacrosse team and I am the Vice President of the Rose Astronomical Society and historian for the Rose chapter of Circle K International. I enjoy physics (especially optics), dancing, playing the piano, skiing, ice skating, singing, reading, doing community service, doing crossword puzzle, and being clean. I hope one day to become a medical physicist.

Useful Links: 

Check out these useful sites:

American Physical Society Statements on Ethics

American Institute of Physics

My Research group's home page

Updated July 31, 2008