Department of Physics and Astronomy

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Dr. Silvina Gatica

Howard University

Wednesday April 16, noon

Thirkield Hall (Physics), room 103

Physics of gases adsorbed in pores, nanotubes and buckyballs

Carbon nanotubes, buckyballs (C₆₀) and materials with nanoporosity represent novel substrates for gas adsorption. This situation has attracted significant experimental and theoretical attention due to many possible practical applications as for example gas storage, gas separation and gas sensors. These studies resulted in a wide variety of interesting behaviors. In this talk I will review some of the properties of gases in these nanostructures that are results of computer simulations and model calculations. For example, xenon adsorbed in an array of buckyballs form a honeycomb lattice gas with a lattice constant significantly larger than in most traditional surfaces. This phase was confirmed by experimental observations (LEED) and an ordering transition is predicted at 20K, yet to be found. The comparison with the experiment, if possible, would permit to inquire about the accuracy of the interaction and models commonly used.

Adsorption of gases is also used to characterize porous materials. Although for many gases the adsorption isotherms show nearly universal behavior, Hydrogen deviates from the universality showing much higher uptake. I will show that the anomalous behavior of Hydrogen is due to quantum effects.

Refreshments will be served