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Christopher J Pursell **
Teaching
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Teaching
Interests
As the chemistry department's only physical chemist, I teach
the year-long physical chemistry lecture courses (PChem 1 in the Fall -
chemical kinetics and thermodynamics; PChem 2 in the Spring - quantum
mechanics, symmetry, spectroscopy, and statistical thermodynamics) and the accompanying
laboratory in the spring. I also periodically teach an advanced topics
course, an advanced laboratory, general chemistry and the general chemistry
laboratory.
Concerning teaching pedagogy, I have been developing new
experiments for the physical chemistry laboratory and new approaches and
lectures for the physical chemistry courses and the general chemistry
courses. I continue to develop new approaches of presenting chemical
concepts in the classroom along with pedagogically sound experiments for both
the physical chemistry laboratory and the introductory general chemistry
laboratory. For example, I reorganized the general chemistry laboratory
course and rewrote the laboratory manual.
Research
- Atmospheric Surface
Chemistry; Guest-Host Binding; Fuel Film Evaporation
1. Atmospheric Surface Chemistry - Our research group has been examining chemical reactions in ice and on ice surfaces. The motivation is to help develop a better understanding of the heterogeneous reactions that occur in the atmosphere and that lead to the seasonal loss of ozone over the poles. In the laboratory we simulate the surface of these atmospheric ice particles, known as Polar Stratospheric Clouds or PSCs, using thin films of pure water ice and mixtures of water with nitric acid. The interaction of reactive species with the ice surface is monitored using infrared transmission spectroscopy. The overall goal is to provide detailed experimental information that will help us better understand the chemical reactivity of the ice surface and ice-like surfaces. Results from these studies will lead to a better understanding of the heterogeneous chemistry that occurs on atmospheric ice particles. An example of one of our recent studies involved examining the isotopic exchange of D2O on H2O ice. Using infrared spectroscopy we were able to monitor the formation of HOD in time and get kinetics information.
Very recently we
have extended our studies of ice and have begun to study the physical and
chemical properties of the molecular cousins of ice, namely solid ammonia and
solid hydrogen sulfide. These studies
involve using infrared spectroscopy, very low temperatures (10-180 K), and a
vacuum environment. We have already
discovered some very fascinating spectroscopic differences between these
“cousins” and ice. We hope
to now study chemical reactions of these solids in order to compare and
contrast their chemical and physical behavior.
2. Guest-Host
Binding - We have recently begun to study the binding of iodine species with
cyclodextrine. This is called guest-host
chemistry. The cyclodextrine is a large,
basket-shaped molecule made from sugar molecules. The iodine species (I-, I2
and I3-) fit inside the cyclodextrine and form a fairly
stable complex. This is an equilibrium
process and we are interested in measuring the equilibrium constant (called the
binding constant) and in determining the heat for this process. Besides using UV-Vis spectroscopy to study
the binding, we are interested in using a new instrument in the department that
can measure the heat associated with the binding processes.
3. Fuel
Film Evaporation - This is a joint project with Dr. Kelly-Zion in the Engineering
Science department. Thin films of fuel
can be deposited in the interior of an automobile engines, especially under
cold, initial operation. These fuel
films lead to reduced performance and increased pollution. We are studying the evaporation process of
model films that represent these automobile fuel films. These studies include (1) using infrared
spectroscopy to watch the individual components evaporate, (2) using light
interference from a laser to measure the film thickness during evaporation, and
(3) using laser light interaction with the film’s surface and capturing
the image with a digital camera (this gives information about turbulence).
4. Characterization of Metallic
Nanoparticle Catalysts - This is a collaborative project with Dr. Chandler
(also in Chemistry), examining the adsorption of gas phase CO to gold supported
nanoparticle catalysts. Using a special
pressure/vacuum/temperature apparatus, along with infrared transmission
spectroscopy, we are able to quantify the amount of CO adsorbed, the binding
constant, and the heat of adsorption.
This allows a thorough characterization of the various gold catalysts.
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** This webpage is maintained by Chris
Pursell. Last modified June 8, 2009.