The Big Dissertation on Small Beryllium Clusters Public

Abstract

  Beryllium is a deceptively simple atom. Despite its simple 1s2 2s2 electronic structure, this closed shell atom participates in a number of anomalous bonding schemes. This simple structure also leads to a surprising amount of theoretical challenge, largely due to the near degeneracy of the Be 2p orbitals with respect to the 2s orbital, which makes it a fantastic system to benchmark high level electronic structure methods. Additionally due to the element's toxicity, very little experimental data is available to compare to electronic structure calculations. In the following work, we present a series of novel studies on Beryllium containing molecules via Slow Electron Velocity-Map Imaging (SEVI) spectroscopy. These studies focus on the electronic structure of both pure beryllium clusters, and hyper-metallic beryllium monoxide clusters, neither of which have been studied by anion photoelectron spectroscopy until this point. With the exception of BeOBe, none of the species presented here have been studied by experimental methods outside of mass spectrometer studies. Ab initio studies of these anions reveal a wealth of knowledge, but some of these clusters still elude exact understanding even with high level theory to assist us.

Table of Contents

1 Introduction 1

1.1 Beryllium Chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.2 Anion Photoelectron Spectroscopy . . . . . . . . . . . . . . . . . . . . 8

2 Experimental Methods 15

2.1 Instrumentation Overview . . . . . . . . . . . . . . . . . . . . . . . . 16

2.2 Generation of Anions . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

2.3 Mass : Charge Discrimination . . . . . . . . . . . . . . . . . . . . . . 22

2.4 Anion Optics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

2.5 Velocity Map Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . 26

2.6 Electron Detection and Imaging . . . . . . . . . . . . . . . . . . . . . 29

2.7 Software and Processing . . . . . . . . . . . . . . . . . . . . . . . . . 30

2.7.1 Acquisition . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

2.7.2 Pre-Processing . . . . . . . . . . . . . . . . . . . . . . . . . . 34

2.7.3 Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

2.8 Spectrum Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

2.9 Experimental Upgrades . . . . . . . . . . . . . . . . . . . . . . . . . . 38

3 A Quirky Little Guy: The Beryllium Trimer and its Anion 43

3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

3.2 Experimental Procedure . . . . . . . . . . . . . . . . . . . . . . . . . 46

3.3 Results and Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . 47

4 Almost an Atom: The Beryllium Tetramer and its Anion 57

4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

4.2 Experimental Procedure . . . . . . . . . . . . . . . . . . . . . . . . . 60

4.3 Results and Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . 61

5 The Youth Taker: The Beryllium Pentamer and its Anion 70

5.1 Background and Introduction . . . . . . . . . . . . . . . . . . . . . . 72

5.2 Experimental Procedure . . . . . . . . . . . . . . . . . . . . . . . . . 73

5.3 Computational Results . . . . . . . . . . . . . . . . . . . . . . . . . . 74

5.4 Experimental Results . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

5.5 Conclusions and Future Areas of Interest . . . . . . . . . . . . . . . . 98

5.6 Be Pentamer Supplemental Info . . . . . . . . . . . . . . . . . . . . . 99

6 All Bets Off: Multireference Problems in Hyper-metallic Beryllium

Oxide Clusters 103

6.1 Introduction and Background . . . . . . . . . . . . . . . . . . . . . . 105

6.2 Computational Studies . . . . . . . . . . . . . . . . . . . . . . . . . . 106

6.3 Experimental Procedure . . . . . . . . . . . . . . . . . . . . . . . . . 112

6.4 Experimental Results . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

6.5 Conclusions and Ongoing work . . . . . . . . . . . . . . . . . . . . . 119

7 The Broken, The Beaten, The Damned: Preliminary Works and

Unsuccessful Attempts on Other Molecules 121

7.1 Beryllium Oxides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

7.1.1 Be2O2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

7.1.2 OBeO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

7.2 SBeS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

7.3 Beryllium Nitrides . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

7.3.1 BeN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

7.3.2 Be3N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

8 When One Door Closes: Conclusions and Future Direction 132

References 133

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School	Laney Graduate School
Department	Chemistry
Degree	Ph.D.
Submission	Dissertation
Language	English
Research Field	Chemistry, Physical Physics, Molecular
Mot-clé	Cluster Anion Spectroscopy Beryllium
Committee Chair / Thesis Advisor	Michael Heaven, Emory University
Committee Members	Francesco Evangelista, Emory University Katherine Davis, Emory University

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