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|Title: ||Joint Density-functional Theory and its Application to Systems in Solution|
|Authors: ||Petrosyan, Sahak|
classical density-functional theory
|Issue Date: ||Aug-2006|
|Abstract: ||The physics of solvation, the interaction of water with solutes,
plays a central role in chemistry and biochemistry, and it is
essential for the very existence of life. Despite the central
importance of water and the advent of the quantum theory early in the
twentieth century, the link between the fundamental laws of physics
and the observable properties of water remain poorly understood to
this day. The central goal of this thesis is to develop a new formalism and framework to make the study of systems (solutes or surfaces) in contact with liquid water as practical and accurate as standard electronic structure
calculations without the need for explicit averaging over large
ensembles of configurations of water molecules.
The thesis introduces a new form of density functional theory for
the ab initio description of electronic systems in contact with a
molecular liquid environment. This theory rigorously joins an
electron density-functional for the electrons of a solute with a
classical density-functional theory for the liquid into a single
variational principle for the free energy of the combined system.
Using the new form of density-functional theory for the ab initio description of electronic systems in contact with a molecular
liquid environment, the thesis then presents the first detailed
study of the impact of a solvent on the surface chemistry of Cr$_2$O$_3$,
the passivating layer of stainless steel alloys. In comparison to a vacuum,
we predict that the presence of water has little impact on the adsorption
of chloride ions to the oxygen-terminated surface but has a dramatic effect
on the binding of hydrogen to that surface.
The thesis then presents a density-functional theory for water which gives reasonable agreement with molecular dynamics simulation data for the solvation of hard spheres in water and sufficient
agreement with experimental data for hydration of inert gas atoms.
By combining the previous ideas, the last study in the thesis presents a model density functional
which includes a description of the coupling of the solvent to the electrons of the solute through a pseudopotential without any empirical fitting of parameters to solvation data.|
|Appears in Collections:||Theses and Dissertations (OPEN)|
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