Clusters (eBook)

Minh Tho NGUYEN is a Full Professor of Chemistry at KU Leuven, Leuven, Belgium.  Boggavarapu KIRAN is an Associate Professor of Chemistry at McNeese State University, Lake Charles, LA, USA.

Preface 6
Contents 10
Contributors 12
1 Global Optimisation Strategies for Nanoalloys 14
Abstract 14
1 Introduction 14
1.1 Global Optimisation 15
1.2 Choice of Energetic Model 17
2 Nature-Inspired GO Methods 20
2.1 Evolutionary Algorithms 20
2.2 Particle Swarms 23
3 Monte Carlo-Based Methods 25
3.1 Basin Hopping 25
3.2 Advancements to MC 26
4 Other Methods 28
4.1 Simulated Annealing 28
4.2 Threshold Algorithm 29
4.3 Discrete Lattice Search 30
4.4 Metadynamics 31
5 Optimisation of Chemical Ordering 31
6 Comparing and Combining GO Methods 35
7 Nanoalloy Case Studies 36
7.1 Coinage Metal Clusters 37
7.2 Noble Metal Clusters 41
7.2.1 Group 10 Bimetallics 41
7.2.2 Noble Metal Mixed Clusters 43
7.3 Main Group-Based Clusters 45
8 Beyond Isolated, Bare Clusters 48
8.1 Surface-Supported Clusters 48
8.1.1 Density Functional Surface GO 50
8.2 Passivated Clusters 52
9 Higher Order Nanoalloys 54
10 Conclusions and Future Outlook 56
Acknowledgments 57
References 58
2 Structural Identification of Doped Silicon Clusters 66
Abstract 66
1 Introduction 67
2 Experimental Techniques to Study Doped Si Clusters in the Gas Phase 69
2.1 Mass Spectrometric Techniques 69
2.2 Infrared Spectroscopy 70
2.3 Photoelectron Spectroscopy 74
2.4 X-Ray Absorption and Magnetic Circular Dichroism Spectroscopy 76
3 Dopant Dependent Growth Mechanisms and Properties 80
3.1 Coinage Metal Dopants (kd10(k + 1)s1) 80
3.2 Transition Metal Dopants (kdx 0  lessthan  x lessthan  10) 83
3.3 Lanthanide Dopants (kfx 0  lessthan  x  lessthan  14) 88
3.4 Non-metallic Main Group Dopants 90
4 Summary and Outlook 92
Acknowledgments 93
References 93
3 Structural Evolution, Vibrational Signatures and Energetics of Niobium Clusters from Nb2 to Nb20 100
Abstract 100
1 Introduction 101
2 Equilibrium Structures and Vibrational Spectra of the Clusters 103
2.1 The Dimers 105
2.2 The Trimers 106
2.3 The Tetramers 108
2.4 The Pentamers 110
2.5 The Hexamers 112
2.6 The Heptamers 114
2.7 The Octamers 115
2.8 The Nonamers 116
2.9 The Decamers 120
2.10 The Undecamers 121
2.11 The Dodecamers 123
2.12 The Tridecamers Nb13 124
2.13 The Tetradecamers Nb14 126
2.14 The Pentadecamers Nb15 127
2.15 The Hexadecamers Nb16 129
2.16 The Heptadecamers Nb17 130
2.17 The Octadecamers Nb18 131
2.18 The Nonadecamers Nb19 132
2.19 The Eicosamers Nb20 134
3 Energetic Properties 135
4 Thermodynamic Stabilities 139
5 Concluding Remarks 145
Acknowledgments 147
References 147
4 Submersion Kinetics of Ionized Impurities into Helium Droplets by Ring-Polymer Molecular Dynamics Simulations 149
Abstract 149
1 Introduction 149
2 Methods 153
2.1 Path-Integral and Ring-Polymer Molecular Dynamics 153
2.2 Observables 155
2.3 Potential Energy Curves 156
3 Results and Discussion 158
3.1 Equilibrium Properties 158
3.2 Submersion Kinetics 160
4 Concluding Remarks 164
References 166
5 Structure, Stability and Electron Counting Rules in Transition Metal Encapsulated Silicon and Germanium Clusters 169
Abstract 169
1 Introduction 170
2 Transition Metal–Silicon Binary Clusters 171
2.1 Structure 171
2.2 Relative Stability of TMSin Clusters 180
3 Transition Metal–Germanium Binary Clusters 199
3.1 Experimental Studies 199
3.2 Theoretical Studies 202
4 Concluding Remarks 208
Acknowledgments 208
References 208
6 Transition Metal Doped Boron Clusters: Structure and Bonding of BnM2 Cycles and Tubes 211
Abstract 211
1 Introduction 211
2 Structural Trend of Pure Boron Clusters 214
3 BnM Clusters with M = Sc and Ti: Formation of Symmetrical Cycles 216
4 The Effects of Iron and Cobalt Dopants 217
4.1 The Effect of Fe 217
4.2 BnM2 and B2nM2 with M2 = Co2, Fe2 and CoFe 219
4.2.1 Geometrical Aspects 219
B6M2 Clusters 219
B7M2: Stabilized Cyclic Isomers 220
Bimetallic Doped B12M2 223
Bimetal Doped B14M2 223
4.2.2 Geometrical Requirements of Bimetal Cyclic and Tubular Structures 224
4.2.3 Formation of Tubes from Bimetallic Tubular Units 225
5 Bimetallic Cyclic Clusters BnM2 with N = 7 and 8 225
5.1 Geometries of B7M2 and B8M2 225
5.2 Chemical Bonding of Bimetallic Cycles 228
5.3 Aromatic Feature of Bimetallic Boron Cyclic Structures 231
6 B14M2: When Bimetallic Tubular Structure Can Be Formed? 234
6.1 Geometrical Identifications 236
6.2 Orbital Interaction 237
6.3 Electronic Requirement 239
7 Chemical Bonding of Transition Metal Doped Boron Clusters 241
7.1 Singly Doped BnM 241
7.2 Bimetal Doped Boron Clusters: The Role of ?* MO 243
8 Concluding Remarks 245
Acknowledgments 245
References 245
7 Silicate Nanoclusters: Understanding Their Cosmic Relevance from Bottom-Up Modelling 248
Abstract 248
1 Introduction 248
1.1 The Origin of Silicates 248
1.2 Finding Low Energy Structures of Si–O-Based Clusters 251
2 Structure and Stability of Silicon Oxide Clusters 253
2.1 Silicon Sub-Oxide Clusters 253
2.2 (SiO2)N Clusters 256
3 Nanosilicates Clusters Around Stars 266
3.1 Nucleation of Silicate Dust 266
3.2 Nanosilicates as Nuclei for H2O Ice Condensation 269
4 Summary and Outlook 275
References 276
8 Magnetic Anisotropy Energy of Transition Metal Alloy Clusters 280
Abstract 280
1 Introduction 281
2 Magnetic Anisotropy in Transition-Metal Alloy Clusters 282
3 Magnetic Anisotropy Energy 283
4 Applications to Transition Metal Mixed Clusters 287
5 Conclusions 297
Acknowledgments 298
References 298
9 Growth Pattern and Size-Dependent Properties of Lead Chalcogenide Nanoclusters 300
Abstract 300
1 Introduction 300
2 Experimental Analysis of PbX (X = S, Se, and Te) Clusters 303
2.1 Early Work 303
2.2 Experimental Analysis of Small Clusters 306
2.3 Cluster Beam Analysis 308
3 Structural Growth Pattern and Energetics of (PbX)n (X = S, Se, and Te) Clusters 310
3.1 Growth Mechanism 310
3.2 Stability and Electronic Structure 324
4 Summary and Outlook 330
Acknowledgments 331
References 331
10 Chemical Reactivity and Catalytic Properties of Binary Gold Clusters: Atom by Atom Tuning in a Gas Phase Approach 335
Abstract 335
1 Introduction 335
2 Experimental Techniques of Gas Phase Reactivity Studies 337
2.1 Production of Metal Clusters 338
2.2 Techniques for Reactivity Studies 340
3 Tuning the Reactive and Catalytic Properties of Binary Gold Clusters 342
3.1 Catalytic CO Oxidation 342
3.1.1 CO Oxidation Mediated by Gold Clusters 344
3.1.2 Activation of Molecular Oxygen by Binary Gold Clusters 348
3.1.3 Adsorption of CO on Binary Gold Clusters 350
3.1.4 CO Oxidation Mediated by Binary Gold Clusters 354
3.2 Activation and Catalytic Conversion of Methane 355
3.2.1 Activation of Methane by gold clusters 356
3.2.2 Activation of Methane by Binary Gold–Palladium Clusters 358
3.3 C–N Coupling 361
3.3.1 C–N Coupling Mediated by Gold and Platinum Cations 362
3.3.2 C–N Coupling by Dinuclear Bimetallic Gold–Platinum Cations 363
3.4 Other Reactions 364
4 Conclusion and Perspective 366
References 366
Index 370