Roman V. Krems

Molecules in Electromagnetic Fields (eBook, PDF)

From Ultracold Physics to Controlled Chemistry

• Format: PDF

Produktbeschreibung

A tutorial for calculating the response of molecules to electric and magnetic fields with examples from research in ultracold physics, controlled chemistry, and molecular collisions in fields Molecules in Electromagnetic Fields is intended to serve as a tutorial for students beginning research, theoretical or experimental, in an area related to molecular physics. The author--a noted expert in the field--offers a systematic discussion of the effects of static and dynamic electric and magnetic fields on the rotational, fine, and hyperfine structure of molecules. The book illustrates how the concepts developed in ultracold physics research have led to what may be the beginning of controlled chemistry in the fully quantum regime. Offering a glimpse of the current state of the art research, this book suggests future research avenues for ultracold chemistry. The text describes theories needed to understand recent exciting developments in the research on trapping molecules, guiding molecular beams, laser control of molecular rotations, and external field control of microscopic intermolecular interactions. In addition, the author presents the description of scattering theory for molecules in electromagnetic fields and offers practical advice for students working on various aspects of molecular interactions. This important text: * Offers information on theeffects of electromagnetic fields on the structure of molecular energy levels * Includes thorough descriptions of the most useful theories for ultracold molecule researchers * Presents a wealth of illustrative examples from recent experimental and theoretical work * Contains helpful exercises that help to reinforce concepts presented throughout text Written for senior undergraduate and graduate students, professors, researchers, physicists, physical chemists, and chemical physicists, Molecules in Electromagnetic Fields is an interdisciplinary text describing theories and examples from the core of contemporary molecular physics.

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Produktdetails

• Verlag: John Wiley & Sons
• Seitenzahl: 384
• Erscheinungstermin: 21. Mai 2018
• Englisch
• ISBN-13: 9781119387350
• Artikelnr.: 54284548

Autorenporträt

ROMAN V. KREMS is a professor of theoretical chemistry at the University of British Columbia in Vancouver, Canada. His current research focuses on understanding the effects of electromagnetic fields on dynamics of few- and many-body molecular systems, the interaction properties of molecules at extremely low temperatures, and applications of machine learning to molecular physics.

Inhaltsangabe

List of Figures xiii List of Tables xxv Preface xxvii Acknowledgments xxxi
1 Introduction to Rotational, Fine, and Hyperfine Structure of Molecular
Radicals 1 1.1 Why Molecules are Complex 1 1.2 Separation of Scales 3 1.2.1
Electronic Energy 5 1.2.2 Vibrational Energy 10 1.2.3 Rotational and Fine
Structure 14 1.3 Rotation of a Molecule 17 1.4 Hund's Cases 21 1.4.1 Hund's
Coupling Case (a) 21 1.4.2 Hund's Coupling Case (b) 22 1.4.3 Hund's
Coupling Case (c) 23 1.5 Parity of Molecular States 23 1.6 General Notation
for Molecular States 27 1.7 Hyperfine Structure of Molecules 28 1.7.1
Magnetic Interactions with Nuclei 28 1.7.2 Fermi Contact Interaction 29
1.7.3 Long-Range Magnetic Dipole Interaction 30 1.7.4 Electric Quadrupole
Hyperfine Interaction 31 Exercises 31 2 DCStarkEffect 35 2.1 Electric Field
Perturbations 35 2.2 Electric Dipole Moment 37 2.3 Linear and Quadratic
Stark Shifts 40 2.4 Stark Shifts of Rotational Levels 42 2.4.1 Molecules in
a 1Sigma Electronic State 42 2.4.2 Molecules in a 2Sigma Electronic State
46 2.4.3 Molecules in a 3Sigma Electronic State 48 2.4.4 Molecules in a 1Pi
Electronic State - Lambda-Doubling 51 2.4.5 Molecules in a 2Pi Electronic
State 54 Exercises 56 3 Zeeman Effect 59 3.1 The Electron Spin 59 3.1.1 The
Dirac Equation 60 3.2 Zeeman Energy of a Moving Electron 63 3.3 Magnetic
Dipole Moment 64 3.4 Zeeman Operator in the Molecule-Fixed Frame 66 3.5
Zeeman Shifts of Rotational Levels 67 3.5.1 Molecules in a 2Sigma State 67
3.5.2 Molecules in a 2Pi Electronic State 71 3.5.3 Isolated Sigma States 74
3.6 Nuclear Zeeman Effect 75 3.6.1 Zeeman Effect in a 1Sigma Molecule 76
Exercises 78 4 ACStarkEffect 81 4.1 Periodic Hamiltonians 82 4.2 The
Floquet Theory 84 4.2.1 Floquet Matrix 88 4.2.2 Time Evolution Operator 89
4.2.3 Brief Summary of Floquet Theory Results 90 4.3 Two-Mode Floquet
Theory 92 4.4 RotatingWave Approximation 94 4.5 Dynamic Dipole
Polarizability 96 4.5.1 Polarizability Tensor 97 4.5.2 Dipole
Polarizability of a DiatomicMolecule 99 4.5.3 Rotational vs Vibrational vs
Electronic Polarizability 101 4.6 Molecules in an Off-Resonant Laser Field
104 4.7 Molecules in a Microwave Field 107 4.8 Molecules in a Quantized
Field 109 4.8.1 Field Quantization 109 4.8.2 Interaction of Molecules with
Quantized Field 116 4.8.3 Quantized Field vs Floquet Theory 117 Exercises
118 5 Molecular Rotations Under Control 121 5.1 Orientation and Alignment
122 5.1.1 OrientingMolecular Axis in Laboratory Frame 123 5.1.2 Quantum
Pendulum 126 5.1.3 Pendular States of Molecules 129 5.1.4 Alignment of
Molecules by Intense Laser Fields 131 5.2 Molecular Centrifuge 136 5.3
OrientingMolecules Matters -Which Side Chemistry 140 5.4 Conclusion 142
Exercises 142 6 External Field Traps 145 6.1 Deflection and Focusing of
Molecular Beams 146 6.2 Electric (and Magnetic) Slowing of Molecular Beams
151 6.3 Earnshaw'sTheorem 155 6.4 Electric Traps 158 6.5 Magnetic Traps 162
6.6 Optical Dipole Trap 165 6.7 Microwave Trap 167 6.8 Optical Lattices 168
6.9 Some Applications of External Field Traps 171 Exercises 173 7 Molecules
in Superimposed Fields 175 7.1 Effects of Combined DC Electric andMagnetic
Fields 175 7.1.1 Linear Stark Effect at Low Fields 175 7.1.2 Imaging of
Radio-Frequency Fields 178 7.2 Effects of Combined DC and AC Electric
Fields 181 7.2.1 Enhancement of Orientation by Laser Fields 181 7.2.2 Tug
ofWar Between DC and Microwave Fields 182 8 Molecular Collisions in
External Fields 187 8.1 Coupled-ChannelTheory of Molecular Collisions 188
8.1.1 A Very General Formulation 188 8.1.2 Boundary Conditions 191 8.1.3
Scattering Amplitude 194 8.1.4 Scattering Cross Section 197 8.1.5
Scattering of Identical Molecules 200 8.1.6 Numerical Integration of
Coupled-Channel Equations 204 8.2 Interactions with External Fields 208
8.2.1 Coupled-Channel Equations in Arbitrary Basis 208 8.2.2 External Field
Couplings 209 8.3 The Arthurs-Dalgarno Representation 211 8.4 Scattering
Rates 214 9 Matrix Elements of Collision Hamiltonians 217 9.1
Wigner-EckartTheorem 218 9.2 Spherical Tensor Contraction 220 9.3
Collisions in a Magnetic Field 221 9.3.1 Collisions of 1S-Atoms with
2Sigma-Molecules 221 9.3.2 Collisions of 1S-Atoms with 3Sigma-Molecules 225
9.4 Collisions in an Electric Field 229 9.4.1 Collisions of 2Pi Molecules
with 1S Atoms 229 9.5 Atom-Molecule Collisions in a Microwave Field 232 9.6
Total Angular Momentum Representation for Collisions in Fields 234 10
Field-Induced Scattering Resonances 239 10.1 Feshbach vs Shape Resonances
239 10.2 The Green's Operator in Scattering Theory 242 10.3 Feshbach
Projection Operators 243 10.4 Resonant Scattering 246 10.5 Calculation of
Resonance Locations andWidths 249 10.5.1 Single Open Channel 249 10.5.2
Multiple Open Channels 249 10.6 Locating Field-Induced Resonances 252 11
Field Control of Molecular Collisions 257 11.1 Why to Control Molecular
Collisions 257 11.2 Molecular Collisions are Difficult to Control 259 11.3
General Mechanisms for External Field Control 261 11.4 Resonant Scattering
261 11.5 Zeeman and Stark Relaxation at Zero Collision Energy 264 11.6
Effect of Parity Breaking in Combined Fields 269 11.7 Differential
Scattering in Electromagnetic Fields 271 11.8 Collisions in Restricted
Geometries 272 11.8.1 Threshold Scattering of Molecules in Two Dimensions
276 11.8.2 Collisions in a Quasi-Two-Dimensional Geometry 280 12 Ultracold
Controlled Chemistry 283 12.1 Can Chemistry Happen at Zero Kelvin? 284 12.2
Ultracold Stereodynamics 287 12.3 Molecular Beams Under Control 289 12.4
Reactions in Magnetic Traps 289 12.5 Ultracold Chemistry - The Why and
What's Next? 291 12.5.1 Practical Importance of Ultracold Chemistry? 291
12.5.2 Fundamental Importance of Ultracold Controlled Chemistry 293 12.5.3
A Brief Outlook 294 A Unit Conversion Factors 297 B Addition of
AngularMomenta 299 B.1 The Clebsch-Gordan Coefficients 301 B.2 TheWigner
3j-Symbols 303 B.3 The Raising and Lowering Operators 304 C Direction
Cosine Matrix 307 D Wigner D-Functions 309 D.1 Matrix elements involving
D-functions 311 E Spherical tensors 315 E.1 Scalar and Vector Products of
Vectors in Spherical Basis 317 E.2 Scalar and Tensor Products of Spherical
Tensors 318 References 321 Index 347