The Chemical Bond

This is the perfect complement to "Chemical Bonding - Across the Periodic Table" by the same editors, who are two of the top scientists working on this topic, each with extensive experience and important connections within the community.
The resulting book is a unique overview of the different approaches used for describing a chemical bond, including molecular-orbital based, valence-bond based, ELF, AIM and density-functional based methods. It takes into account the many developments that have taken place in the field over the past few decades due to the rapid advances in quantum chemical models and faster computers.

Autorentext
Gernot Frenking studied chemistry at the Technical University Aachen (Germany). He then became a research atudent in the group of Prof. Kenichi Fukui in Kyoto (Japan) and completed his PhD and his habilitation at Technical University Berlin (Germany). He was then a visiting scientist at the University of California, Berkeley (USA) and a staff scientist at SRI International in Menlo Park, California (USA). Since 1990 he is Professor for Computational Chemistry at the Philipps-Universitat Marburg.

Sason Shaik is a graduate of the University of Washington (USA), where he also obtained his PhD. After a postdoctoral year at Cornell University, he became Lecturer at Ben-Gurion University of the Negev (Israel), where he became Professor in 1988. In 1992 he moved to The Hebrew University where he is Professor and the Director of the Lise Meitner-Minerva Center for Computational Quantum Chemistry.

Klappentext
One of the fundamental territories of chemistry is the chemical bond, the glue from which an entire chemical universe is constructed. For a while it seemed that Chemists have, by and large, abandoned their territory as if everything about bonding is known and well understood; the frontier has moved to Nano and Bio, leaving the original territory untended. This however was a wrong impression, since the interest in bonding has quickly revived to be accompanied by many interesting theoretical approaches to probe the origins of bonds, many novel bonding motifs, and even experimental studies that describe imaging of bonds being broken and remade using atomic force microscopy. The bond is becoming again a central intellectual arena. Enormous progress was made in recent time in method development which gives insight into the chemical bond using calculated numbers which come from sophisticated quantum chemical methods in line with the famous statement of Charles Coulson: "Give us insight not numbers". This "return of the bond" has prompted the two editors to edit these two volumes on bonding, and it is only fitting that their publication date is close to the centenary of the Lewis seminal paper on electron pair bonding. The two volumes are meant to attract the interest of the practicing chemist, teachers and advanced students who may want to learn about the present understanding of chemical bonding.

Volume 1 contains eleven chapters, which provide the theoretical frameworks of the various perspectives on bonding, coming from VB and MO theories, ELF, AIM, NBO, BLW and EDA. This Volume lays the foundations for the applications across the periodic table.

Inhalt

Preface xiii

List of Contributors xxiii

**1 The Physical Origin of Covalent Bonding 1
Michael W. Schmidt, Joseph Ivanic, and Klaus Ruedenberg

1.1 The Quest for a Physical Model of Covalent Bonding 1

1.2 Rigorous Basis for Conceptual Reasoning 3

1.3 Atoms in Molecules 10

1.4 The One-Electron Basis of Covalent Binding: H2+ 13

1.5 The Effect of Electronic Interaction in the Covalent Electron Pair Bond: H2 34

1.6 Covalent Bonding in Molecules with More than Two Electrons: B2 ,C2 , N2 ,O2 ,and F2 51

1.7 Conclusions 62

Acknowledgments 65

References 65

**2 Bridging Cultures 69
Philippe C. Hiberty and Sason Shaik

2.1 Introduction 69

2.2 A Short History of the MO/VB Rivalry 69

2.3 Mapping MO-Based Wave Functions to VB Wave Functions 74

2.4 Localized Bond Orbitals A Pictorial Bridge between MO and VB Wave Functions 78

2.5 Block-Localized Wave Function Method 79

2.6 Generalized Valence Bond Theory: a Simple Bridge from VB to MOs 80

2.7 VB Reading of CASSCF Wave Functions 82

2.8 Natural Bonding Orbitals and Natural Resonance Theory a Direct Bridge between MO and VB 83

2.9 The Mythical Conflict of Hybrid Orbitals with Photoelectron Spectroscopy 85

2.10 Conclusion 87

Appendix 88

References 88

**3 The NBO View of Chemical Bonding 91
Clark R. Landis and Frank Weinhold

3.1 Introduction 91

3.2 Natural Bond Orbital Methods 92

3.3 Beyond Lewis-Like Bonding: The DonorAcceptor Paradigm 106

3.4 Conclusion 117

References 118

**4 The EDA Perspective of Chemical Bonding 121
Gernot Frenking and F. Matthias Bickelhaupt

4.1 Introduction 121

4.2 Basic Principles of the EDA Method 125

4.3 The EDA-NOCV Method 126

4.4 Chemical Bonding in H2 and N2 127

4.5 Comparison of Bonding in Isoelectronic N2 ,CO and BF 133

4.6 Bonding in the Diatomic Molecules E 2 of the First Octal Row E = LiF 135

4.7 Bonding in the Dihalogens F2 I2 144

4.8 CarbonElement Bonding in CH3 -X 146

4.9 EDA-NOCV Analysis of Chemical Bonding in the Transition State 148

4.10 Summary and Conclusion 155

Acknowledgements 156

References 156

**5 The Valence Bond Perspective of the Chemical Bond 159
Sason Shaik, David Danovich, Wei Wu, and Philippe C. Hiberty

5.1 Introduction 159

5.2 A Brief Historical Recounting of the Development of the Chemical Bond Notion 160

5.3 The PaulingLewis VB Perspective of the Electron-Pair Bond 162

5.4 A Preamble to the Modern VB Perspective of the Electron-Pair Bond 165

5.5 Theoretical Characterization of Bond Types by VB and Other Methods 168

5.6 Trends of Bond Types Revealed by VB, AIM and ELF 170

5.7 Physical Origins of CS Bonding 178

5.8 Global Behavior of Electron-Pair Bonds 181

5.9 Additional Factors of CS Bonding 183

5.10 Can a Covalent Bond Become CS Bonds by Substitution? 184

5.11 Experimental Manifestations of CS Bonding 187

5.12 Scope and Territory of CS Bonding 190

Appendix 192

5.A Modern VB Methods 192

5.B The Virial Theorem 193

5.C Resonance Interaction and Kinetic Energy 195

References 195

**6 The Block-Localized Wavefunction (BLW) Perspective of Chemical Bonding 199
Yirong Mo

6.1 Introduction 199

6.2 Methodology Evolutions 202

6.3 Exemplary Applications 209

6.4 Conclusion 223 &...