Structure and stability of quantum H2 films on ionic surfaces : a theoretical study
department or school: Science, Irving K. Barber Faculty of (Okanagan)
department or school: Chemistry, Department of (Okanagan)
data provider: DSpace
degree campus: UBCO
creator: Sadeghifar, Alireza
issued: 2020-08-31T17:07:38Z
issued: 2020
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: The process of H₂ adsorption on ionic surfaces has long been of importance technologically as well as of interest to “pure” science because they constitute simple ideal systems that may be subject to quantum effects. Experiments have shown that these systems can form a sequence of structures that undergo phase transitions. In particular, there is evidence that H₂/MgO(100) exhibits the following sequence of structural phase transitions: c(2×2) → c(4×2) → c(6×2). The details of these structures and their stabilities are not yet understood. This thesis presents an investigation of the H₂/NaCl(100) and H₂/MgO(100) systems where the detailed structures of these films and their stabilities are determined through the use of Monte Carlo simulations in the canonical ensemble. Key to this study is a hierarchy of newly developed H₂-H₂ and H₂–surface interaction potentials that depend on the quantum mechanical rotational state of the molecule(s) and are presented here for the first time. Using these potentials, it was found that the structure of the H₂ films depend on whether the molecules were in the para (J=0) or ortho (J=1) rotational state, or alternatively consisted of a mixture of molecules in these different rotational states. In addition, the external vibrational frequencies of the H₂ molecules with respect to the surface were calculated. Overall, the structure, stability, and external vibrational frequencies of the H₂/NaCl(100) and H₂/MgO(100) systems were found to match or be consistent with experimental results. They also provided details, e.g. molecular locations, that are not accessible experimentally. Consequently, a more complete and coherent picture of the H₂/NaCl(100) and H₂/MgO(100) systems has emerged.
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/75760
note: Structure and Stability of Quantum H2 Films on Ionic Surfaces: A Theoretical Study by Alireza Sadeghifar B.Sc., University of Mazandaran, Iran, 2003 M.Sc., Amirkabir University of Technology (Tehran Polytechnic), Iran, 2010 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE COLLEGE OF GRADUATE STUDIES (Chemistry) THE UNIVERSITY OF BRITISH COLUMBIA (Okanagan) August 2020 © Alireza Sadeghifar, 2020 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the dissertation entitled: Structure and Stability of Quantum H2 Films on Ionic Surfaces: A Theoretical Study submitted by Alireza Sadeghifar in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Chemistry Examining Committee: Dr. David B. Jack, Department of Chemistry, Irving K. Barber Faculty of Science, UBC Supervisor Dr. Gino A. DiLabio, Department of Chemistry, Irving K. Barber Faculty of Science, UBC Supervisory Committee Member Dr. Isaac T. S. Li, Department of Chemistry, Irving K. Barber Faculty of Science, UBC Supervisory Committee Member Dr. Lukas Bichler, School of Engineering, UBC University Examiner Dr. Jan Peter Toennies, Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany External Examiner iii Abstract The process of H2 adsorption on ionic surfaces has long been of importance technologically as well as of interest to “pure” science because they constitute simple ideal systems that may be subject to quantum effects. Experiments have shown that these systems can form a sequence of structures that undergo phase transitions. In particular, there is evidence that H2/MgO(100) exhibits the following sequence of structural phase transitions: c(2×2) → c(4×2) → c(6×2). The details of these structures and their stabilities are not yet understood. This thesis presents an investigation of the H2/NaCl(100) and H2/MgO(100) sys…
has type: Thesis/Dissertation
date issued: 2020-09
is shown at: 10.14288/1.0394096
language: eng
degree discipline: Chemistry
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/75760