Simulation of the equilibrium constant of the weak electrolyte solution using the subspace sampling method.
Item
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Title
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Simulation of the equilibrium constant of the weak electrolyte solution using the subspace sampling method.
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Identifier
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AAI9605662
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identifier
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9605662
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Creator
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Shew, Chwen-Yang.
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Contributor
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Adviser: Pamela Mills
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Date
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1995
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, Physical | Chemistry, Inorganic
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Abstract
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The Monte Carlo method is a powerful tool to compute the thermodynamic and structural properties of condensed phase problem. During my dissertation research, we developed a novel Monte Carlo method--the Subspace Sampling Methods. The method combines the free energy difference method with some other Monte Carlo methods. The method divides configuration space into two subspaces. The two subspaces are sampling using two processes. One is a transfer process, which manages the crossing process from one subspace to another in an analogous manner to the acceptance ratio method of free energy difference calculation. The other is the move process, which is the transition in the individual subspace. In the simulation of the double well potential, the results demonstrate that the method can really facilitate the barrier crossing with a high efficiency. The convergence is more rapid than that of any other method. Due to the versatility of the method, it can be employed to simulate both continuous and discontinuous potential systems. The equilibrium constant and the density function (or other thermodynamic properties) is simulated simultaneously. In other words, the method is applicable to investigate the equilibrium properties of chemical reaction systems which are quite difficult for other methods. Recently, we carried out the simulation for the divalent weak electrolyte system based on the Sticky Electrolyte Model. The model is composed of the primitive model for strong electrolyte solutions and a sticky molecular potential. The high energy barrier in this model impedes ion pairs association to form molecules. Although, standard Monte Carlo algorithms cannot simulate the system efficiently, the Subspace Sampling Method proved amenable to compute the equilibrium constant and pair correlation function. We compare the results of the simulation with those of analytic solutions (MSA/HNC and HNC). The simulation equilibrium constant has a similar behavior to that obtained from the analytic solution. However, the magnitude of the simulated equilibrium constants are one order greater. The simulated contact correlation function is smaller. The value is more close to the result of MSA/HNC than that of using HNC alone.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
