Files in this item

FilesDescriptionFormat

application/pdf

9712290.pdf (5MB)
(no description provided)PDF

Description

 Title: Quantum Monte Carlo methods for molecular systems: New developments and applications Author(s): Grossman, Jeffrey Curtis Doctoral Committee Chair(s): Ceperley, David M. Department / Program: Physics Discipline: Physics Degree Granting Institution: University of Illinois at Urbana-Champaign Degree: Ph.D. Genre: Dissertation Subject(s): Physics, Condensed Matter Abstract: The goals of our research have been to: (i) expand the applicability of the quantum Monte Carlo (QMC) methods to larger molecular systems and check the reliability of traditional approaches, (ii) determine the impact of correlation energy on a variety of systems in which correlation is important, (iii) investigate new silicon clusters which may generate unique materials, (iv) determine the most stable C$\sb{10}$ and C$\sb{20}$ clusters, (v) achieve kcal/mol accuracy for molecular reactions, and (vi) develop the QMC methodology by improving the QMC trial functions. In order to attain these goals, we have unambiguosly determined the role of correlation energy in silicon and carbon systems, calculated binding energies, barrier heights, heats of formation, and electron affinities for selected molecular systems with high accuracy, and gauged the performance and predictability of more than ten standard methods. We have also shown that the utilization of natural orbitals leads to a significant improvement in the quality of the trial wavefunctions. We demonstrate that, through a combination of advances in both accuracy and scaling, QMC is a highly attractive alternative to the traditional methods, and for some cases it appears to be the only currently available approach to provide parameter-free predictions for energies of systems with more than 40 electrons. Issue Date: 1996 Type: Text Language: English URI: http://hdl.handle.net/2142/21991 ISBN: 9780591198300 Rights Information: Copyright 1996 Grossman, Jeffrey Curtis Date Available in IDEALS: 2011-05-07 Identifier in Online Catalog: AAI9712290 OCLC Identifier: (UMI)AAI9712290
﻿