David Kelsey

Graduate Student Chandler Group Department of Chemistry University of California at Berkeley Berkeley, CA 94720 Phone: 510-643-7128 Fax: 510-643-1566 Email: dkelsey"AT"berkeley"DOT"edu

Research

I have been studying the physics of glassy materials using simple, minimal models. The models are kinetically constrained lattice gases, and they have been shown (by the Chandler group and others) to exhibit many of the key features of real supercooled liquid behavior. My early work involved using these well-established models to investigate the effect of externally applied forces on glassy systems. In particular, I simulated pulling a probe particle through a glassy solvent and studied the steady-state velocity as a function of applied force. The central result is the observation that, in certain force and density regimes, the velocity is non-monotonic. In other words, it is possible to actually slow the particle down by pulling on it harder. This seemingly counterintuitive behavior can be well explained as a consequence of the largely heterogeneous dynamics of the system.

I am currently studying chemical catalysis. Phenomenological kinetics can describe steady-state dynamics satisfactorily at the mean-field level, but it leaves out microscopic fluctuations that may be important. Kinetic Monte Carlo, armed with some knowledge/assumptions of rate constants, can be used to simulate reactions at this microscopic level. I'm using this powerful tool to study reactions that are important in energy production/storage. Specifically, I am looking at the effect of substrate geometry and heterogeneity on reaction activity, a problem that could not be treated with a mean-field analysis alone. This is something that is of current experimental interest, so the goal would be to assist/explain/guide new technological advances in renewable energy catalysis.

Publications

• "Negative differential mobility of weakly driven particles in models of glass formers," Jack, R.L., D. Kelsey, J.P. Garrahan and D. Chandler, Phys. Rev. E 78, 011506 (2008)

Teaching

• Chem 220A: Thermodynamics and Statistical Mechanics - Fall 2008
• Chem 120B: Thermodynamics and Statistical Mechanics - Spring 2006
• Chem 1A: General Chemistry - Fall 2004

Education

B.S. in Chemistry, 2004, University of North Carolina at Wilmington

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Last updated: 2/5/2008