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Theoretical Calculations for Electron Impact Ionization of Atoms and Molecules

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Theoretical Calculations for Electron Impact Ionization of Atoms and Molecules Scholars' Mine Doctoral Dissertations Student Theses and Dissertations Fall 2017 Theoretical calculations for electron impact ionization of atoms and molecules Sadek Mohamed Fituri Amami Follow this and additional works at: https://scholarsmine.mst.edu/doctoral_dissertations Part of the Atomic, Molecular and Optical Physics Commons Department: Physics Recommended Citation Amami, Sadek Mohamed Fituri, "Theoretical calculations for electron impact ionization of atoms and molecules" (2017). Doctoral Dissertations. 2617. https://scholarsmine.mst.edu/doctoral_dissertations/2617 This thesis is brought to you by Scholars' Mine, a service of the Missouri S&T Library and Learning Resources. This work is protected by U. S. Copyright Law. Unauthorized use including reproduction for redistribution requires the permission of the copyright holder. For more information, please contact [email protected]. THEORETICAL CALCULATIONS FOR ELECTRON IMPACT IONIZATION OF ATOMS AND MOLECULES by SADEK MOHAMED FITURI AMAMI A DISSERTATION Presented to the Graduate Faculty of the MISSOURI UNIVERSITY OF SCIENCE AND TECHNOLOGY In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY in PHYSICS 2017 Approved by Don H. Madison, Advisor Jerry L. Peacher Michael Schulz Daniel Fischer Gregory Gelles Copyright 2017 SADEK MOHAMED FITURI AMAMI All Rights Reserved iii PUBLICATION DISSERTATION OPTION This dissertation consists of the following ten articles which have been published as follows: Paper I: Pages 31-54 have been published by Phys Rev A.91.032707 (March 2015). Paper II: Pages 55-78 have been published by Phys Rev A.90.012704 (July 2014). Paper III: Pages 79-93 have been published by J. Phys. B: At. Mol. Opt. Phys. 49 185202 (September 2016). Paper IV: Pages 94-118 have been published by Phys Rev A.93.062704 (June 2016). Paper V: Pages 119-143 have been published by Phys Rev A.90.062707 (December 2014). Paper VI: Pages 144-148 have been published by PhysRevA.91.069906 (June 2015). Paper VII: Pages 149-165 have been published by PhysRevA.92 032706 (September 2015). Paper VIII: Pages 166-184 have been published by J. Phys. B: At. Mol. Opt. Phys (January 2009). Paper IX: Pages 185-205 have been published by PhysRevA.95.022701 (February 2017). Paper X.: Pages 206-224 have been published by THE JOURNAL OF CHEMICAL PHYSICS 136, 094302 (March 2012). Paper XI. Pages 225-244 have been submitted to J. Phys. B: At. Mol. Opt. Phys (September 2017) iv ABSTRACT In the last twenty years, significant progress has been made for the theoretical treat- ment of electron impact ionization (e,2e) of atoms and molecules and, for some cases, very nice agreement between experiment and theory has been achieved. In particular, excellent agreement between theory and experiment and theory has been achieved for ionization of hydrogen and helium. However, agreement between experiment and theory is not nearly as good for ionization of larger atoms and molecules. In the first part of this dissertation, dif- ferent theoretical approaches will be employed to study the triply differential cross section (TDCS) for low and intermediate energy electron-impact ionization of Neon and Argon for different orbital states. There is a very recent interest in studying ionization of Laser aligned atoms in order to get a better understanding about electron impact ionization of molecules. In the next part of this dissertation, results will be presented for electron-impact ionization of three laser aligned atoms, Mg, Ca, and Na. The comparison between the theory and experiment showed that our three body distorted wave (3DW) model gave excellent agree- ment with experiment in the scattering plane but very poor agreement perpendicular to the scattering plane. An explanation for this poor agreement out of the scattering plane has been provided by comparing our theoretical results with those of the time depended close coupling (TDCC) model and this explanation is also provided in this dissertation. Recently, significant attention has been directed towards obtaining a better under- standing of electron-impact ionization of molecules which are significantly more challeng- ing than atoms. In the last part of this dissertation, results will be presented for electron- impact ionization of three different molecules (N2 , H2O, and CH4 ) which have been studied comprehensively using different theoretical approximations for different types of geometries. The published papers in section two contain a detailed analysis and discussion for each of these topics. v ACKNOWLEDGMENTS The first appreciation goes to my family, especially my father and mother for the remarkable and valuable support since I was little kid until this moment. My father was always behind my success during all my educational stages. He always believed that I will get whatever I was seeking and pursuing. At the same level, I got all the emotional support and love from my mother as well. She was and still is the spring of love, kindness, and tenderness. Also, I am really thankful to my wife who stood beside me, supported me, and worked very hard to provide me an appropriate study environment. Utmost appreciation and gratitude goes to my advisors, Dr. Madison and Dr. Peacher, for their support and guidance throughout my graduate study. Special thanks goes to my advisor, Dr. Madison, for his help, patience, and guidance as I completed my PhD. An extended appreciation goes to my advisory committee, Dr. Michael Schulz, Dr. Daniel Fischer and Dr. Gregory Gelles, for their remarkable questions and patience. Also, my thanks go to all my professors who taught me the graduate courses. To all faculty and staff members, my colleagues, my friends in the physics department, and friends in our community who stood beside me with support and love when my house burned, today I say thank you all. Special thanks go to the Police and fire departments, ICRM and Red Cross for their valuable support. My deepest appreciation goes to my friend, Yousef Elmehdwi, and his family, for his hospitality, open arms, warm heart during that event and after, and all his help. Last but not the least, I am thankful to everyone in the physics department, international affairs, and graduate office for making our university campus a very good environment for students with full support. Thanks to the Ministry of Higher Education in Libya and Tripoli University Scholarship, as well as the physics department and the NSF for financial supports. vi TABLE OF CONTENTS Page PUBLICATION DISSERTATION OPTION . iii ABSTRACT.................................................................. iv ACKNOWLEDGMENTS . v LIST OF ILLUSTRATIONS . xiii SECTION 1. GENERAL INTRODUCTION . 1 2. GEOMETRIES AND KINEMATICS OF THE STUDY . 8 3. THEORETICAL MODELS AND APPROXIMATIONS . 12 3.1. THEORY OF ELECTRON IMPACT IONIZATION .......................... 12 3.2. DIFFERENTIAL CROSS SECTIONS FOR ATOMS AND MOLECULES . 13 3.2.1. Scattering Theory ....................................................... 14 3.2.2. The Lippmann-Schwinger Equation ................................... 16 3.2.3. Born Approximations and its First Order .............................. 18 3.3. DISTORTED WAVE BORN APPROXIMATION ............................. 22 3.4. THREE-BODY DISTORTED WAVE APPROXIMATION (3DW) ........... 25 3.5. WARD AND MACEK APPROXIMATION ................................... 29 vii PAPER I. KINEMATICALLY COMPLETE STUDY OF LOW-ENERGY ELECTRON- IMPACT IONIZATION OF NEON: INTERNORMALIZED CROSS SECTIONS IN 3D KINEMATICS . 31 ABSTRACT ............................................................................ 31 1. INTRODUCTION ............................................................... 32 2. EXPERIMENT .................................................................. 34 3. THEORETICAL MODELS ..................................................... 35 3.1. DWB2-RM .............................................................. 35 3.2. BSR...................................................................... 36 3.3. The Three-Body Distorted-Wave Approximation..................... 37 3.3.1. 3DW .......................................................... 37 3.3.2. DWBA-WM .................................................. 39 4. RESULTS AND DISCUSSION ................................................ 41 5. CONCLUSIONS ................................................................. 49 ACKNOWLEDGMENTS ............................................................. 50 REFERENCES ......................................................................... 50 II. THEORETICAL AND EXPERIMENTAL INVESTIGATION OF (e,2e) ION- IZATION OF ARGON (3p) IN ASYMMETRIC KINEMATICS AT INTER- MEDIATE ENERGY . 55 ABSTRACT ............................................................................ 55 1. INTRODUCTION ............................................................... 56 2. EXPERIMENTAL APPARATUS .............................................. 59 3. THEORY......................................................................... 60 3.1. 3DW ..................................................................... 60 3.2. DWB2-RM .............................................................. 62 3.3. BSR...................................................................... 62 viii 4. RESULTS ........................................................................ 65 5. CONCLUSION .................................................................. 68 ACKNOWLEDGMENTS ............................................................. 70 REFERENCES ........................................................................
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