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Ab Initio Search for Novel Bxhy Building Blocks with Potential for Hydrogen Storage

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Ab Initio Search for Novel Bxhy Building Blocks with Potential for Hydrogen Storage Utah State University DigitalCommons@USU All Graduate Theses and Dissertations Graduate Studies 12-2010 Ab Initio Search for Novel BxHy Building Blocks with Potential for Hydrogen Storage Jared K. Olson Utah State University Follow this and additional works at: https://digitalcommons.usu.edu/etd Part of the Physical Chemistry Commons Recommended Citation Olson, Jared K., "Ab Initio Search for Novel BxHy Building Blocks with Potential for Hydrogen Storage" (2010). All Graduate Theses and Dissertations. 844. https://digitalcommons.usu.edu/etd/844 This Dissertation is brought to you for free and open access by the Graduate Studies at DigitalCommons@USU. It has been accepted for inclusion in All Graduate Theses and Dissertations by an authorized administrator of DigitalCommons@USU. For more information, please contact [email protected]. AB INITIO SEARCH FOR NOVEL BXHY BUILDING BLOCKS WITH POTENTIAL FOR HYDROGEN STORAGE by Jared K. Olson A dissertation submitted in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY in Chemistry (Physical Chemistry) Approved: Dr. Alexander I. Boldyrev Dr. Steve Scheiner Major Professor Committee Member Dr. David Farrelly Dr. Stephen Bialkowski Committee Member Committee Member Dr. T.C. Shen Byron Burnham Committee Member Dean of Graduate Studies UTAH STATE UNIVERSITY Logan, Utah 2010 ii Copyright © Jared K. Olson 2010 All Rights Reserved iii ABSTRACT Ab Initio Search for Novel BxHy Building Blocks with Potential for Hydrogen Storage by Jared K. Olson, Doctor of Philosophy Utah State University, 2010 Major Professor: Dr. Alexander I. Boldyrev Department: Chemistry and Biochemistry On-board hydrogen storage presents a challenging barrier to the use of hydrogen as an energy source because the performance of current storage materials falls short of platform requirements. Because boron is one of the lightest chemical elements that can form strong covalent bonds with hydrogen, it provides an excellent opportunity to design new lightweight materials on the basis of novel boron hydride building blocks. Realizing this potential requires an understanding of the electronic structure, chemical bonding, and stability of neutral and anionic BxHy clusters with variable stoichiometry. While a large number of boron hydride compounds are known, there are still entire classes of yet unknown neutral and anionic BxHy clusters and molecules with various new x/y ratios which may be good candidates for hydrogen storage or as intermediates of borane de- hydrogenation. The primary aim of this dissertation was to search for neutral and anionic BxHy clusters that are thermochemically stable towards hydrogen release and to understand the chemical bonding in these novel clusters. These goals were accomplished iv by performing an unbiased search for neutral and anionic global minimum BxHy clusters using ab initio methods. In addition to finding a rich variety of new neutral and anionic BxHy (x = 3 – 6 and y = 4 – 7) clusters that could be building blocks for novel hydrogen-boron materials during the course of conducting this research, optical isomerism was discovered in select neutral and anionic boron-hydride clusters. Furthermore, the transition from planar to 3- - dimensional geometries in global minimum B6Hx clusters was discovered using ab initio techniques during this study. Chemical bonding analysis using the AdNDP method was performed for all global minimum structures and low-lying isomers. The chemical bonding pattern recovered by the AdNDP method in all cases is consistent with the geometric structure. The theoretical vertical detachment energies presented in this dissertation may help interpret future photoelectron spectroscopic studies of the anions presented here. (106 pages) v DEDICATION To Shirlene, Olivia, and Aidan. vi ACKNOWLEDGMENTS I express my sincere gratitude to my advisor, Professor Alexander I. Boldyrev, for all I have learned from him throughout my tenure as a graduate student at Utah State University. He helped me greatly to develop my skills in quantum chemistry, to master the methodology of successful research, and to gain a deep appreciation for the tenacity required to perform such research. I thank all the members of my supervisory committee: Dr. Steve Scheiner, Dr. David Farrelly, Dr. Stephen Bialkowski, and Dr. T.C. Shen. I appreciate their support, encouragement, and openness for questions and discussions, which greatly influenced my progress and professional growth. I express my gratitude to Dr. Boldyrev and the committee for the patience and flexibility they exercised in facilitating my studies here. I express my deep appreciation for my wife, Shirlene, for her love and patience during the last several years. I thank Brent H. Larsen, Nathan Seidner, Dr. Sarah Hiza, Dr. Daniel Doll, Dr. James Burns, and Dr. Robert Wardle at ATK Launch Systems for their encouragement and support during my studies at Utah State University. I also thank my parents for their encouragement. This theoretical work was supported partially by the National Science Foundation (CHE-0714851). Computer time from the Center for High Performance Computing at Utah State University is gratefully acknowledged. The computational resource, the Uinta cluster supercomputer, was provided through the National Science Foundation under Grant CTS-0321170 with matching funds provided by Utah State University. An vii allocation of computer time from the Center for High Performance Computing at the University of Utah is also gratefully acknowledged. Jared K. Olson viii CONTENTS Page ABSTRACT ....................................................................................................................... iii DEDICATION .....................................................................................................................v ACKNOWLEDGMENTS ................................................................................................. vi LIST OF TABLES ...............................................................................................................x LIST OF FIGURES ........................................................................................................... xi CHAPTER 1. INTRODUCTION .......................................................................................1 1-1. Background ......................................................................................1 1-2. Specific Goals ..................................................................................1 1-3. Motivation ........................................................................................2 1-4. Relevant Prior Work ........................................................................2 1-5. Theoretical Methods ........................................................................6 1-6. References ........................................................................................9 2. AB INITIO SEARCH FOR GLOBAL MINIMUM STRUCTURES OF THE NOVEL B3HY (Y=4-7) NEUTRAL AND ANIONIC CLUSTERS................................................................................................17 Abstract ..........................................................................................17 2-1. Introduction ....................................................................................17 2-2. Computational Details ...................................................................20 2-3. Computational Results ...................................................................22 - 2-4. Chemical Bonding in B3Hx and B3Hx (x=4-7) Species .................26 2-5. Conclusions ....................................................................................34 2-6. References ......................................................................................34 3. AB INITIO SEARCH FOR GLOBAL MINIMUM STRUCTURES OF NEUTRAL AND ANIONIC B4H4 CLUSTERS .................................40 Abstract ..........................................................................................40 3-1. Introduction ....................................................................................40 3-2. Computational Details ...................................................................41 3-3. Results and Discussion ..................................................................43 3-4. Summary and Conclusions ............................................................50 ix 3-5. References ......................................................................................50 4. AB INITIO SEARCH FOR GLOBAL MINIMUM STRUCTURES OF NEUTRAL AND ANIONIC B4H5 CLUSTERS .......................................57 Abstract ..........................................................................................57 4-1. Computational Details ...................................................................57 4-2. Results and Discussion ..................................................................58 4-3. Conclusions ....................................................................................64 4-4. References ......................................................................................65 5. AB INITIO DISCOVERY OF THE PLANAR TO 3-DIMENSIONAL - TRANSITION IN B6HX CLUSTERS .......................................................68 Abstract ..........................................................................................68 5-1. Computational Details ...................................................................69 5-2. Results and Discussion ..................................................................70
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