International Research Fellowship Program: Ab Initio Study of Aqueous Polyions

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0903342BogatkoThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-four-month research fellowship by Dr. Stuart A. Bogatko to work with Dr. Paul Geerlings at Free University of Brussels in Belgium.The environmental impact of new industrial and energy technologies is today a main subject of public discussion. Of prime concern is the possible migration of toxic material from industrial sites or containment facilities into the biosphere. The Aluminum(III) ion is of particular importance because it is found in the by-products of important industrial activities such as processing of bauxite to form pure alumina and the reclamation of hydrocarbons from deep deposits. Unfortunately it is also a known neurotoxin disrupting essential biological processes in plants and animals and may possibly play a role in Alzheimer?s disease. Contact with the aqueous phase would undoubtedly play a major role in the migration of toxic aluminum species. In solution Al3+ exists in a variety of oxohydroxo polyion species such as [Al(H2O)6]3+, [Al2(OH)2(H2O)8]4+, [Al3(OH)4(H2O)9]5+, [Al4(OH)6(H2O)11]6+, [Al4O(OH)5(H2O)10]5+ and [AlO4Al12(OH)24(H2O)12]7+. The chemical reactivity of these species determines whether further polymerization, dissociation or adsorption on mineral surfaces will occur. This study addresses these concerns. The reactivity indices, such as nucleophilicity, electrophilicity and chemical hardness, of these species are evaluated using high level quantum chemistry methods in a variety of aqueous environments including effects of solution pH, counter-ions, temperature and pressure. Experimental methods have seen limited success due to the complexity of these systems. First principles theoretical investigations have thus become an invaluable tool not only supplementing experimental data but also in prediction of new properties. A realistic simulation poses a significant computational challenge because a large number of atoms are required to model the solvation effects and an efficient and high level molecular dynamics algorithm needs to be used to include the effects of temperature and pressure. This is achieved using the Conceptual Density Functional Theory (CDFT) methods, whose concepts have been developed and implemented by Professor Paul Geerlings of Vrije Universiteit Brussels (VUB), and the high performance Pseudo-Potential Plane-Wave Density Functional Theory (PSPW-DFT) algorithms developed by Professor John Weare of the University of California San Diego (UCSD). The joining of these methods represents a major step in the field of Quantum Computational Chemistry towards producing highly accurate, quantitative chemical information of a system whose size and complexity represents the ?state of the art?.