Lehigh University Lehigh Preserve Theses and Dissertations 2017 Matrix-Isolation Studies of Ionic CO2 Clusters and Improvements on the Counter Ion Co-Deposition Technique Michael Edward Goodrich Lehigh University Follow this and additional works at: http://preserve.lehigh.edu/etd Part of the Chemistry Commons Recommended Citation Goodrich, Michael Edward, "Matrix-Isolation Studies of Ionic CO2 Clusters and Improvements on the Counter Ion Co-Deposition Technique" (2017). Theses and Dissertations. 2607. http://preserve.lehigh.edu/etd/2607 This Dissertation is brought to you for free and open access by Lehigh Preserve. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of Lehigh Preserve. For more information, please contact [email protected]. Matrix-Isolation Studies of Ionic CO2 Clusters And Improvements on the Counter Ion Co-Deposition Technique by Michael Edward Goodrich A Dissertation Presented to the Graduate and Research Committee of Lehigh University in Candidacy for the Degree of Doctor of Philosophy in Chemistry Lehigh University May 2017 © 2017 Copyright Michael Edward Goodrich ii Approved and recommended for acceptance as a dissertation in partial fulfillment of the requirements for the degree of Doctor of Philosophy Michael Goodrich Matrix-Isolation Studies of Ionic CO2 Complexes and Improvements on the Counter Ion Co-Deposition Technique Defense Date Dr. Xiaoji Xu Approved Date Committee Members: Dr. David T. Moore Dr. Gregory S. Ferguson Dr. James Roberts Dr. Nicholas Strandwitz iii ACKNOWLEDGMENTS I would like to begin by thanking my high school chemistry teacher, Mr. John Munday, who inspired my interest in chemistry. I dedicate this dissertation to his memory. To my research advisor, Dr. David Moore: Thank you for being a wonderful teacher and mentor over these past five years, and of course, for teaching me that “you gotta want it.” Thank you to the rest of my dissertation committee, Dr. Ferguson, Dr. Roberts, Dr. Strandwitz, and Dr. Xu, for your guidance and support. I would like to thank my former lab mates, especially Ryan Ludwig, who was a great mentor and friend throughout our time in the Moore group. Succeeding in graduate school would not have been possible without the constant encouragement and support of my parents, my wife Kim, and countless friends. I would especially like to thank Kim for her love and unending support during my time in graduate school, and for always being there to talk me off the ledge when I was convinced I wasn’t going to make it through. I couldn’t have done it without you! iv TABLE OF CONTENTS Copyright……………………………………………………………………………...ii Certificate of Approval………………………………………………………………iii Acknowledgements..…………………………………………………………………iv List of Figures…………………………………………………………………………x List of Tables……………………………………………………………………….xvii Abstract………………………………………………………………………………..1 Chapter 1: Matrix Isolation Spectroscopy and its Application for the Study of Ionic Species…………………………………………………………..……………….4 1.1 Matrix Isolation Spectroscopy……………………………………………..4 1.1.1 Matrix Materials………………………………………………….5 1.1.2 Crystal Structure of the Matrix..…………………………………6 1.1.3 Trapping Sites……………………………………………………7 1.1.4 Annealing and Diffusion………………………………………...9 1.1.5 Probability of Isolation…………………………………………10 1.1.6 Matrix Effects on Spectroscopy………………………………...11 1.1.7 Reaction Kinetics in Matrix-Isolation…………………………..13 1.2 Ion Generation for Matrix-Isolation Studies.……………………………..14 1.2.1 High-Energy Deposition of Externally Generated Ions………...14 1.2.2 Deposition of Mass-Selected Cations…………………………..15 1.2.3 The Counter Ion Co-Deposition Method……………………….16 1.3 Matrix-Isolated Metal Carbonyls…………………………………………18 1.4 Dissertation Outline………………………………………………………20 v Chapter 2: Experimental Methods…………………………………………………22 2.1 Introduction……………………………………………………….………22 2.2 Counter Ion Co-Deposition and Matrix-Isolation Instrument Overview…23 2.2.1 Instrument Modifications to Allow for Simultaneous Mass Selection of Ions………………………………………………..27 2.2.2 Matrix-Deposition Chamber…...……………………………….29 2.3 Ion Generation and Delivery……………………………………………...31 2.3.1 Metal-Ion Generation…………………………………………...31 2.3.2 Counter Cation Generation and Charge Balance……………….33 2.3.3 Ion Energy………………………………………………………34 2.3.4 Chemical Ionization Source…………………………………….35 2.4 Matrix-Gas Mixing and Delivery…………………………………………38 2.5 Data Collection and Processing…………………………………………..40 2.6 Appendix…………………………………………………………………42 Chapter 3: Characterization of Ionic CO2 Complexes using the Counter Ion Co- Deposition Technique……………………………………………………………….47 3.1 Abstract…………………………………………………………………..47 3.2 Introduction……………………………………………………………....47 3.3 Experimental Methods…………………………………………………...48 3.4 Results and Discussion……………………………………………………49 - 3.4.1 Characterization of CuCO2 …………………………………….49 - - 3.4.2 Counter Ion Effects on Formation of CO2 and (CO2)(CO2 )…..51 3.4.3 Counter Ion Effects on Formation of Cationic CO2 Species…...55 vi 3.4.4 High-Temperature Deposition………………...………………..57 3.4.5 Ionic CO2 Species in Krypton and Nitrogen Matrices………….59 3.5 Conclusions……………………………………………………………….62 3.6 Appendix………………………………………………………………….62 Chapter 4: Identification of a Low Temperature Thermodynamic Equilibrium Involving Isomers of CO2 Dimer Anions in Cryogenic Argon and Krypton Matrices………………………………………………………………………………64 4.1 Abstract…………………………………………………………………...64 4.2 Introduction……………………………………………………………….65 4.2.1 Thermodynamic Equilibria in Matrix Isolation………………...67 4.3 Experimental Methods.…………………………………………………...69 4.4 Results…………………………….………………………………………72 4.4.1 Argon Matrices…………………………………………………72 4.4.2 Thermodynamic van’t Hoff Analysis…………………………..75 4.4.3 Kinetic Analysis………………………………………………...78 4.4.4 Transition State Theory: The Eyring Equation…………………83 4.4.5 Nitrogen and Krypton Matrices………………………………...85 4.5 Discussion………………………………………………………………...88 4.6 Conclusions and Future Work…………………………………………….94 4.7 Appendix………………………………………………………………….95 4.7.1 Peak Fitting……………………………………………………..99 4.7.2 Derivation and Explanation of Kinetic Fitting Equations………97 vii 4.7.3 Temperature Dependent Rate Constants………………………102 - 4.7.4 Temperature Dependence of CO2 …………………………….106 4.7.5 Other Relevant Spectroscopic Signatures……………………..108 Chapter 5: The Effect of Matrix-Deposition Temperature on the Formation of Matrix-Isolated Copper Carbonyl Anions………………………………………..111 5.1 Abstract………………………………………………………………….111 5.2 Introduction……………………………………………………………..111 5.3 Experimental Methods.………………………………………………….113 5.4 Results…………………………………………………………………...113 5.4.1 Deposition Spectra…………………………………………….114 5.4.2 Annealing Behavior…………………………………………...116 5.4.3 Photolysis……………………………………………………...117 5.5 Discussion……………………………………………………………….118 5.6 Appendix………………………………………………………………..122 Chapter 6: Improvements in Ion Delivery for Matrix Isolation Spectroscopy: Simultaneous Deposition of Mass Selected Anions and Cations………………...124 6.1 Abstract………………………………………………………………….124 6.2 Introduction……………………………………………………………...125 6.3 Experimental Methods.………………………………………………….127 6.4 Results and Discussion…………………………………………………..128 6.5 Appendix………………………………………………………………...136 6.5.1 Neutral SF6…………………………………………………….136 6.5.2 Stopping Potential Curves……………………………………..137 viii Chapter 7: Conclusions and Future Work……………………………………….140 7.1 Conclusions……………………………………………………………...140 7.2 Future Directions………………………………………………………..142 7.2.1 Characterization of the CO2 Dimer Anion Equilibrium……….142 7.2.2 Utilizing the Chemical Ionization Source……………………..143 Chapter 8: List of References……………………………………………………..145 Curriculum Vita……………………………………………………………………154 ix LIST OF FIGURES Figure 2.1 Original design of the counter ion co-deposition and matrix isolation system. Figure adapted from reference 40……………………………24 Figure 2.2 Schematic illustration of a quadrupole ion bender. The positively and negatively biased poles allow oppositely charged ion beams entering opposite sides of the bender to be combined and exit as a single beam…………………………………………………………………..25 Figure 2.3 Block diagram of the updated instrument showing the fifth differentially pumped chamber. The four original chambers remained unchanged. Counter ions are now generated in the electron impact (EI) or chemical ionization (CI) sources in chamber 5. As with the original system, the two ion beams are combined in the bender and directed into the outupole ion guide and onto the deposition window…………………29 Figure 2.4 Image of the deposition chamber taken from the perspective of the flange where the external IR beam enters the chamber, showing the orientation of the IR window relative to the octupole output, matrix gas line, and Faraday plate………………………………………………..30 Figure 2.5 Schematic diagram of the deposition chamber and detection scheme for the matrix isolation instrument which shows the direction of the IR beam path through the deposition chamber and into the external MCT- A detector. SolidWorks file created by Alex Hunter. Figure taken from Reference 43...………………………………………………………..31 Figure 2.6 Schematic diagram of unmodified OAR magnetron sputtering source taken from Reference 44. The aggregation region was water cooled, rather than liquid nitrogen cooled, as shown in the figure. The length of the aggregation chamber could be modified using the linear drive. The custom nozzle (not shown) to improve ion extraction was installed at the left aperture, as labeled in the figure…………………………...32 Figure 2.7 Picture of chemical ionization source mounted to differential pumping plate. The