Using Molecular-Level Simulations to Determine Diffusivities in the Classroom


  • D.J. Keffer University of Tennessee
  • Austin Newman University of Tennessee
  • Parag Adhangale University of Tennessee


We present work describing the practical use of molecular-level simulations to determine diffusivities in a course targeted at the general audience of first-year chemical engineering graduate students. We show how the simulation techniques can be used to directly complement traditional methods for obtaining diffusivities. Our philosophy is to provide a utilitarian tool that can be used in a manner analogous to existing techniques to obtain diffusion coefficients. The advantage of the simulation approach is that it will work in the absence of experimental data and can be easily applied to multicomponent mixtures with an arbitrary number of species. In the implementation of this work, we remain keenly aware of constraints due to time, computational resources, money, and target-audience qualifications, so that the implementation is feasible. We demonstrate that these simulations require only a few minutes to run on a contemporary (AMD Athlon 850 MHz) processor. In our approach we outline the basic steps necessary to obtain a transport diffusivity via molecular-level simulations. We also provide an example problem, where we compare the results of the simulation to the predictions from corresponding states and kinetic theory.

Author Biographies

D.J. Keffer, University of Tennessee

David Keffer has been an assistant professor in the Department of Chemical Engineering at the University of Tennessee since January, 1998. His research involves. among other things. computational description of the behavior of nanoscopically confined fluids. using molecular-level simulation techniques.

Austin Newman, University of Tennessee

Austin Newman is in the process of completing his degree requirements for a Master of Science in Chemical Engineering at the University of Tennessee. He is working with statistical mechanical models that describe the transport of fluids in nanoporous materials.

Parag Adhangale, University of Tennessee

Parag Adhangale received his BS from the University of Bombay and his MS from North Carolina Agricultural and Technical State University, both in chemical engineering. He is currently pursuing a PhD at the University of Tennessee. His research involves molecular and process simulations of adsorption of multicomponent systems in nanoporous materials.