SaM Researchers in the News

kenjordan-imageDensity functional theory has evolved into the most widely used method for the computational characterization of the electronic structure of complex materials. However it is well know that standard DFT methods do not describe long-range dispersion interaction. Recently Ken Jordan, co-director of SaM, his student Ozan Vierlatiz and Wissam Saide of Chemical Engineering at Pitt, introduced an extended method originally introduced by Rothlesberger and co-workers for connecting DFT for long-range dispersion interactions. As of March 10, this was the 4th most downloaded paper in Chemical Physics Letters over the past 90 days. [O. Varlati, W. A. Saida, and K. D. Jordan, Chemical Physics Letters 591, 133-137 (2014)]


An accurate description of the interactions between gas molecules and SWNTs is important for designing better materials for adsorption and purification of fluids using these nanoporous materials. Towards this, Center for Simulation and Modeling (SaM)-affiliated researchers De-Li Chen, Wissam A. Saidi, and J. Karl Johnson recently published two papers, in conjunction with collaborators at Penn State and the University of Virginia where atomistic simulations were used to predict the outcome of experiments carried out by their colleagues at UVa. The papers were published in the Journal of the American Chemical Society, 135, 7768-7776 (2013) DOI: 10.1021/ja402928s and Physical Review Letters, 110 135503 (2013) DOI: 10.1103/PhysRevLett.110.135503. The calculations predicted that the interaction energies between gases and either metallic or semiconducting single walled carbon nanotubes (SWNTs) would be the same, as long as the diameters of the nanotubes were the same. Specific calculations were carried out for adsorption of noble gases and n heptane on a series of nanotubes that were either metallic or semiconducting, having similar diameters. The theoretical predictions were confirmed by temperature programmed desorption experiments carried out at UVa on samples of purified metallic or semiconducting SWNTs.

About the Center for Simulation and Modeling

The Center for Simulation and Modeling (SaM) at the University of Pittsburgh is dedicated to supporting and facilitating computational-based research across campus. SaM serves as a catalyst for multidisciplinary collaborations among professors, sponsors modeling-focused seminars, teaches graduate-level modeling courses and provides individual consultation in modeling to all researchers at the University. Our areas of research include: energy and sustainability, nanoscience and materials engineering, medicine and biology, and economics and the social sciences.