THEORETICAL STUDIES OF SOLUTION PHASE CHEMISTRY (STATISTICAL MECHANICS, POTENTIAL MEAN FORCE, LIQUID WATER, DILUTE SOLUTION)
Abstract
Monte Carlo simulations for pure liquid water, methanol in water and a nucleophilic addition reaction in water have been carried out in the NPT ensemble at 1 atm at 25 C. The pure liquid water simulations were run at various temperatures and sizes to test the precision of the potential functions. The methanol in water simulation addresses the conformational change going from gas phase to aqueous solution. It was determined that no conformational change occurs going from gas phase to aqueous solution. Also, the umbrella sampling procedure was used to aid in the convergence of the conformational properties. Finally; a simulation of a nucleophilic addition reaction, hydroxide anion adding to formaldehyde in water, was performed. First a detailed gas phase potential energy surface was determined. Then using the gas phase energy and importance sampling techniques a potential of mean force was found via an NPT Monte Carlo procedure. An aqueous phase transition state was located along the free energy curve. Finally; simulations of the solutes held at distances corresponding to the intermediate, transition state and reactants were carried out. From these fixed solute simulations structural details were obtained.
Degree
Ph.D.
Subject Area
Chemistry
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