Project Research Staff (Postdoc) with
JSPS Postdoc with Koichi Yamashita
Postdoc for John C Tully, Yale Chemistry
Short Term Postdoc for George C Schatz
PhD, Chemistry, Northwestern U.
advisors: G. Schatz and
BS, Chemistry, Texas A&M U.
Place of Birth: Ft. Worth, Texas
Sept 2002-Sept 2004
Feb 2002-Aug 2002
July 22, 1975
My research can be
generally categorized as using computers to gain
insight on emerging problems in chemistry, material science, and
nanotechnology. I enjoy working closely with experimental
collaborators, which has been a continuing trend in my work. My
proposed research is available upon request. Outlined
here is my
current and previous work.
Research in the Tully Group
delved into the problem of surface erosion that occurs to satellites
space shuttles as they orbit the earth. This work was completely
new to me, and one publication is expected in 2005. Low Earth
Orbit (LEO) is
approximately 300 km up, where the atmosphere is faint, but still
present. The predominant chemical species is atomic oxygen in
lowest energy quantum electronic state O(3P).
materials are known to degrade rapidly in LEO, and are thought to react
efficiently upon impact with the incident O atoms. At these
orbital velocities, each collision imparts a kinetic energy of about 5
eV, or roughly 450 kJ/mol. This energy is larger than the range
considered in combustion chemistry, and well under the energies typical
in particle physics.
Details of the most
important mechanism of surface degradation are unknown. Our
approach to the problem is multifaceted, including examining the
fundamental interactions via ab
dynamics (CPMD and VASP), building a new semi-empirical model for
somewhat larger scale dynamics, and my specific project:
simulating erosion morphologies on the macroscopic scale.
The latter is implemented via a kinetic Monte Carlo (KMC) routine
written in FORTRAN. We consider graphite as a test material, and
then apply lessons learned to more advanced materials, such as the
My previous research at Northwestern
University under George Schatz and Richard Van Duyne dealt with the
optical properties of noble metal nanoparticles. Gold, silver,
copper particles exhibit optical activity in the visible range; meaning
they strongly absorb and scatter light of different wavelengths.
This has been known experimentally for a very long time:
gold colloid (spherical shaped particles, mostly) produce the
brilliant red color of many medieval windows. Silver colloid
imparts a yellow color and copper a greenish one, but they have been
produced with efficiency only recently, thus aren't as prominent in
historical items. Advanced sensor technologies are being
now which utilize these spectral properties.
also play a starring role in the mystery of surface enhanced spectroscopies, a
topic related to proposed optical technologies and single (small)
molecule detection. Molecules behave differently when they are
near a rough noble metal surface (such as a nanoparticle), and often
times their spectral signal is enhanced by many orders of
magnitude. The primary mechanism of this enhancement is
electromagnetic, where the particle enhances the light's electric field
near the surface.
Both of these applications are well served by methods of classical electromagnetics. My dissertation describes several methods (numeric and analytic) applied to gold and silver particles of various sizes and shapes, with emphasis on trigonal particles. Experimentally relevant parameters such as surrounding media (suspending solution or solid support) were included in the study of spectral properties and the surrounding electric field.
in Japan. My recent research addresses photochromic activity of
TiO2 films with embedded silver nanoparticles. Using similar
techniques as my graduate research, we've elucidated the most probable
nanostructure for the metal embedded deep within the film. More
details will be available follwing hopeful publication of our recently
submitted paper. (September, 2005)
My career goals, to attain a professor position at a college or university with a balance between instruction and research. Finding a good scholarly and personal fit is the most important factor in my search of chemistry departments. I intend to continue computer-based research, and I'm also looking forward to opportunities for experimental work and collaboration.
modified April 26 2007 klk