Relativistic Quantum Chemistry: The Fundamental Theory of Molecular Science, 2nd EditionISBN: 9783527334155
750 pages
January 2015

Description
This second edition expands on some of the latest developments in this fascinating field. The text retains its clear and consistent style, allowing for a readily accessible overview of the complex topic. It is also selfcontained, building on the fundamental equations and providing the mathematical background necessary. While some parts of the text have been restructured for the sake of clarity a significant amount of new content has also been added. This includes, for example, an indepth discussion of the BrownRavenhall disease, of spin in currentdensity functional theory, and of exact twocomponent methods and its local variants.
A strength of the first edition of this textbook was its list of almost 1000 references to the original research literature, which has made it a valuable reference also for experts in the field. In the second edition, more than 100 additional key references have been added  most of them considering the recent developments in the field.
Thus, the book is a musthave for everyone entering the field, as well as for experienced researchers searching for a consistent review.
Table of Contents
Preface XXI
1 Introduction 1
1.1 Philosophy of this Book 1
1.2 Short Reader’s Guide 4
1.3 Notational Conventions and Choice of Units 6
Part I — Fundamentals 9
2 Elements of Classical Mechanics and Electrodynamics 11
2.1 Elementary Newtonian Mechanics 11
2.1.1 Newton’s Laws of Motion 11
2.1.2 Galilean Transformations 14
2.1.3 Conservation Laws for One Particle in Three Dimensions 20
2.1.4 Collection of N Particles 21
2.2 Lagrangian Formulation 22
2.2.1 Generalized Coordinates and Constraints 22
2.2.2 Hamiltonian Principle and Euler–Lagrange Equations 24
2.2.3 Symmetries and Conservation Laws 28
2.3 Hamiltonian Mechanics 31
2.3.1 Hamiltonian Principle and Canonical Equations 31
2.3.2 Poisson Brackets and Conservation Laws 33
2.3.3 Canonical Transformations 34
2.4 Elementary Electrodynamics 35
2.4.1 Maxwell’s Equations 36
2.4.2 Energy and Momentum of the Electromagnetic Field 38
2.4.3 Plane Electromagnetic Waves in Vacuum 40
2.4.4 Potentials and Gauge Symmetry 42
2.4.5 Survey of Electro– and Magnetostatics 45
2.4.6 One Classical Particle Subject to Electromagnetic Fields 47
2.4.7 Interaction of Two Moving Charged Particles 50
3 Concepts of Special Relativity 53
3.1 Einstein’s Relativity Principle and Lorentz Transformations 53
3.1.1 Deficiencies of Newtonian Mechanics 53
3.1.2 Relativity Principle of Einstein 55
3.1.3 Lorentz Transformations 58
3.1.4 Scalars, Vectors, and Tensors in Minkowski Space 62
3.2 Kinematic Effects in Special Relativity 67
3.2.1 Explicit Form of Special Lorentz Transformations 67
3.2.2 Length Contraction, Time Dilation, and Proper Time 72
3.2.3 Addition of Velocities 75
3.3 Relativistic Dynamics 78
3.3.1 Elementary Relativistic Dynamics 79
3.3.2 Equation of Motion 83
3.3.3 Lagrangian and Hamiltonian Formulation 86
3.4 Covariant Electrodynamics 90
3.4.1 Ingredients 91
3.4.2 Transformation of Electromagnetic Fields 95
3.4.3 Lagrangian Formulation and Equations of Motion 96
3.5 Interaction of Two Moving Charged Particles 101
3.5.1 Scalar and Vector Potentials of a Charge at Rest 102
3.5.2 Retardation from Lorentz Transformation 104
3.5.3 General Expression for the Interaction Energy 105
3.5.4 Interaction Energy at One Instant of Time 105
3.5.5 Symmetrized Darwin Interaction Energy 112
4 Basics of Quantum Mechanics 117
4.1 The Quantum Mechanical State 118
4.1.1 Bracket Notation 118
4.1.2 Expansion in a Complete Basis Set 119
4.1.3 Born Interpretation 119
4.1.4 State Vectors in Hilbert Space 121
4.2 The Equation of Motion 122
4.2.1 Restrictions on the Fundamental Quantum Mechanical Equation 122
4.2.2 Time Evolution and Probabilistic Character 123
4.2.3 Stationary States 123
4.3 Observables 124
4.3.1 Expectation Values 124
4.3.2 Hermitean Operators 125
4.3.3 Unitary Transformations 126
4.3.4 Heisenberg Equation of Motion 127
4.3.5 Hamiltonian in Nonrelativistic Quantum Theory 129
4.3.6 Commutation Relations for Position and Momentum Operators 131
4.3.7 The Schrödinger Velocity Operator 132
4.3.8 Ehrenfest and Hellmann–Feynman Theorems 133
4.3.9 Current Density and Continuity Equation 135
4.4 Angular Momentum and Rotations 139
4.4.1 Classical Angular Momentum 139
4.4.2 Orbital Angular Momentum 140
4.4.3 Coupling of Angular Momenta 145
4.4.4 Spin 147
4.4.5 Coupling of Orbital and Spin Angular Momenta 149
4.5 Pauli Antisymmetry Principle 155
Part II — Dirac’s Theory of the Electron 159
5 Relativistic Theory of the Electron 161
5.1 Correspondence Principle and Klein–Gordon Equation 161
5.1.1 Classical Energy Expression and First Hints from the Correspondence Principle 161
5.1.2 Solutions of the Klein–Gordon Equation 163
5.1.3 The Klein–Gordon Density Distribution 164
5.2 Derivation of the Dirac Equation for a Freely Moving Electron 166
5.2.1 Relation to the Klein–Gordon Equation 166
5.2.2 Explicit Expressions for the Dirac Parameters 167
5.2.3 Continuity Equation and Definition of the 4Current 169
5.2.4 Lorentz Covariance of the FieldFree Dirac Equation 170
5.3 Solution of the FreeElectron Dirac Equation 173
5.3.1 Particle at Rest 173
5.3.2 Freely Moving Particle 175
5.3.3 The Dirac Velocity Operator 179
5.4 Dirac Electron in External Electromagnetic Potentials 181
5.4.1 Kinematic Momentum 184
5.4.2 Electromagnetic Interaction Energy Operator 184
5.4.3 Nonrelativistic Limit and Pauli Equation 185
5.5 Interpretation of NegativeEnergy States: Dirac’s Hole Theory 187
6 The Dirac Hydrogen Atom 193
6.1 Separation of Electronic Motion in a Nuclear Central Field 193
6.2 Schrödinger Hydrogen Atom 197
6.3 Total Angular Momentum 199
6.4 Separation of Angular Coordinates in the Dirac Hamiltonian 200
6.4.1 Spin–Orbit Coupling 200
6.4.2 Relativistic Azimuthal Quantum Number Analog 201
6.4.3 FourDimensional Generalization 203
6.4.4 Ansatz for the Spinor 204
6.5 Radial Dirac Equation for HydrogenLike Atoms 204
6.5.1 Radial Functions and Orthonormality 205
6.5.2 Radial Eigenvalue Equations 206
6.5.3 Solution of the Coupled Dirac Radial Equations 207
6.5.4 Energy Eigenvalue, Quantization and the Principal Quantum Number 213
6.5.5 The FourComponent Ground State Wave Function 215
6.6 The Nonrelativistic Limit 216
6.7 Choice of the Energy Reference and Matching Energy Scales 218
6.8 Wave Functions and Energy Eigenvalues in the Coulomb Potential 219
6.8.1 Features of Dirac Radial Functions 219
6.8.2 Spectrum of Dirac Hydrogenlike Atoms with Coulombic Potential 221
6.8.3 Radial Density and Expectation Values 223
6.9 Finite Nuclear Size Effects 225
6.9.1 Consequences of the Nuclear Charge Distribution 227
6.9.2 Spinors in External Scalar Potentials of Varying Depth 229
6.10 Momentum Space Representation 233
Part III — FourComponent ManyElectron Theory 235
7 Quantum Electrodynamics 237
7.1 Elementary Quantities and Notation 237
7.1.1 Lagrangian for Electromagnetic Interactions 237
7.1.2 Lorentz and Gauge Symmetry and Equations of Motion 238
7.2 Classical Hamiltonian Description 240
7.2.1 Exact Hamiltonian 240
7.2.2 The Electron–Electron Interaction 241
7.3 SecondQuantized FieldTheoretical Formulation 243
7.4 Implications for the Description of Atoms and Molecules 246
8 FirstQuantized DiracBased ManyElectron Theory 249
8.1 TwoElectron Systems and the Breit Equation 250
8.1.1 Dirac Equation Generalized for Two BoundState Electrons 251
8.1.2 The Gaunt Operator for Unretarded Interactions 253
8.1.3 The Breit Operator for Retarded Interactions 256
8.1.4 Exact Retarded Electromagnetic Interaction Energy 260
8.1.5 Breit Interaction from Quantum Electrodynamics 266
8.2 QuasiRelativistic ManyParticle Hamiltonians 270
8.2.1 Nonrelativistic Hamiltonian for a Molecular System 270
8.2.2 FirstQuantized Relativistic ManyParticle Hamiltonian 272
8.2.3 Pathologies of the FirstQuantized Formulation 274
8.2.4 Local Model Potentials for OneParticle QED Corrections 278
8.3 Born–Oppenheimer Approximation 279
8.4 Tensor Structure of the ManyElectron Hamiltonian andWave Function 283
8.5 Approximations to the ManyElectron Wave Function 285
8.5.1 The IndependentParticle Model 286
8.5.2 Configuration Interaction 287
8.5.3 Detour: Explicitly Correlated Wave Functions 291
8.5.4 Orthonormality Constraints and Total Energy Expressions 292
8.6 Second Quantization for the ManyElectron Hamiltonian 296
8.6.1 Creation and Annihilation Operators 296
8.6.2 Reduction of Determinantal Matrix Elements to Matrix Elements Over Spinors 297
8.6.3 ManyElectron Hamiltonian and Energy 299
8.6.4 Fock Space and Occupation Number Vectors 300
8.6.5 Fermions and Bosons 301
8.7 Derivation of Effective OneParticle Equations 301
8.7.1 Avoiding Variational Collapse: The Minimax Principle 302
8.7.2 Variation of the Energy Expression 304
8.7.3 SelfConsistent Field Equations 306
8.7.4 Dirac–Hartree–Fock Equations 309
8.7.5 The Relativistic SelfConsistent Field 312
8.8 Relativistic Density Functional Theory 313
8.8.1 Electronic Charge and Current Densities for Many Electrons 314
8.8.2 CurrentDensity Functional Theory 317
8.8.3 The FourComponent Kohn–Sham Model 318
8.8.4 Electron Density and Spin Density in Relativistic DFT 320
8.8.5 Relativistic SpinDFT 322
8.8.6 Noncollinear Approaches and Collinear Approximations 323
8.8.7 Relation to the Spin Density 324
8.9 Completion: The CoupledCluster Expansion 325
9 ManyElectron Atoms 333
9.1 Transformation of the ManyElectron Hamiltonian to Polar Coordinates 335
9.1.1 Comment on Units 336
9.1.2 Coulomb Interaction in Polar Coordinates 336
9.1.3 Breit Interaction in Polar Coordinates 337
9.1.4 Atomic ManyElectron Hamiltonian 341
9.2 Atomic ManyElectron Wave Function and jjCoupling 341
9.3 One and TwoElectron Integrals in Spherical Symmetry 344
9.3.1 OneElectron Integrals 344
9.3.2 Electron–Electron Coulomb Interaction 345
9.3.3 Electron–Electron FrequencyIndependent Breit Interaction 349
9.3.4 Calculation of Potential Functions 351
9.4 Total Expectation Values 354
9.4.1 General Expression for the Electronic Energy 354
9.4.2 Breit Contribution to the Total Energy 356
9.4.3 Dirac–Hartree–Fock Total Energy of ClosedShell Atoms 357
9.5 General SelfConsistentField Equations and Atomic Spinors 358
9.5.1 Dirac–Hartree–Fock Equations 360
9.5.2 Comparison of Atomic Hartree–Fock and Dirac–Hartree–Fock Theories 361
9.5.3 Relativistic and Nonrelativistic Electron Densities 364
9.6 Analysis of Radial Functions and Potentials at Short and Long Distances 366
9.6.1 ShortRange Behavior of Atomic Spinors 367
9.6.2 Origin Behavior of Interaction Potentials 370
9.6.3 ShortRange Electron–Electron Coulomb Interaction 371
9.6.4 Exchange Interaction at the Origin 372
9.6.5 Total Electron–Electron Interaction at the Nucleus 376
9.6.6 Asymptotic Behavior of the Interaction Potentials 378
9.7 Numerical Discretization and Solution Techniques 379
9.7.1 Variable Transformations 381
9.7.2 Explicit Transformation Functions 382
9.7.3 Transformed Equations 383
9.7.4 Numerical Solution of Matrix Equations 386
9.7.5 Discretization and Solution of the SCF equations 388
9.7.6 Discretization and Solution of the Poisson Equations 391
9.7.7 Extrapolation Techniques and Other Technical Issues 393
9.8 Results for Total Energies and Radial Functions 395
9.8.1 Electronic Configurations and the Aufbau Principle 397
9.8.2 Radial Functions 397
9.8.3 Effect of the Breit Interaction on Energies and Spinors 399
9.8.4 Effect of the Nuclear Charge Distribution on Total Energies 400
10 General Molecules and Molecular Aggregates 403
10.1 Basis Set Expansion of Molecular Spinors 405
10.1.1 Kinetic Balance 408
10.1.2 Special Choices of Basis Functions 409
10.2 Dirac–Hartree–Fock Electronic Energy in Basis Set Representation 413
10.3 Molecular One and TwoElectron Integrals 419
10.4 Dirac–Hartree–Fock–Roothaan Matrix Equations 419
10.4.1 Two Possible Routes for the Derivation 420
10.4.2 Treatment of NegativeEnergy States 421
10.4.3 FourComponent DFT 422
10.4.4 Symmetry 423
10.4.5 Kramers’ Time Reversal Symmetry 423
10.4.6 Double Groups 424
10.5 Analytic Gradients 425
10.6 PostHartree–Fock Methods 428
Part IV — TwoComponent Hamiltonians 433
11 Decoupling the NegativeEnergy States 435
11.1 Relation of Large and Small Components in OneElectron Equations 435
11.1.1 Restriction on the Potential Energy Operator 436
11.1.2 The XOperator Formalism 436
11.1.3 FreeParticle Solutions 439
11.2 ClosedForm Unitary Transformation of the Dirac Hamiltonian 440
11.3 The FreeParticle Foldy–Wouthuysen Transformation 443
11.4 General Parametrization of Unitary Transformations 447
11.4.1 ClosedForm Parametrizations 448
11.4.2 Exactly Unitary Series Expansions 449
11.4.3 Approximate Unitary and Truncated Optimum Transformations 451
11.5 Foldy–Wouthuysen Expansion in Powers of 1/c 454
11.5.1 The LowestOrder Foldy–Wouthuysen Transformation 454
11.5.2 SecondOrder Foldy–Wouthuysen Operator: Pauli Hamiltonian 458
11.5.3 HigherOrder Foldy–Wouthuysen Transformations and Their Pathologies 459
11.6 The InfiniteOrder TwoComponent TwoStep Protocol 462
11.7 Toward WellDefined Analytic BlockDiagonal Hamiltonians 465
12 Douglas–Kroll–Hess Theory 469
12.1 Sequential Unitary Decoupling Transformations 469
12.2 Explicit Form of the DKH Hamiltonians 471
12.2.1 First Unitary Transformation 471
12.2.2 Second Unitary Transformation 472
12.2.3 Third Unitary Transformation 475
12.3 InfiniteOrder DKH Hamiltonians and the ArbitraryOrder DKH Method 476
12.3.1 Convergence of DKH Energies and Variational Stability 477
12.3.2 InfiniteOrder Protocol 479
12.3.3 Coefficient Dependence 481
12.3.4 Explicit Expressions of the PositiveEnergy Hamiltonians 483
12.3.5 Additional Peculiarities of DKH Theory 485
12.4 ManyElectron DKH Hamiltonians 488
12.4.1 DKH Transformation of OneElectron Terms 488
12.4.2 DKH Transformation of TwoElectron Terms 489
12.5 Computational Aspects of DKH Calculations 492
12.5.1 Exploiting a Resolution of the Identity 494
12.5.2 Advantages of ScalarRelativistic DKH Hamiltonians 496
12.5.3 Approximations for Complicated Terms 498
12.5.4 DKH Gradients 500
13 Elimination Techniques 503
13.1 Naive Reduction: Pauli Elimination 503
13.2 Breit–Pauli Theory 507
13.2.1 Foldy–Wouthuysen Transformation of the Breit Equation 508
13.2.2 Transformation of the TwoElectron Interaction 509
13.2.3 The Breit–Pauli Hamiltonian 518
13.3 The Cowan–Griffin andWood–Boring Approaches 522
13.4 Elimination for Different Representations of Dirac Matrices 523
13.5 Regular Approximations 524
Part V — Chemistry with Relativistic Hamiltonians 527
14 Special Computational Techniques 529
14.1 From the Modified Dirac Equation to ExactTwoComponent Methods 530
14.1.1 Normalized Elimination of the Small Component 531
14.1.2 ExactDecoupling Methods 533
14.1.3 Approximations in ManyElectron Calculations 546
14.1.4 Numerical Comparison 548
14.2 Locality of Relativistic Contributions 551
14.3 Local Exact Decoupling 553
14.3.1 Atomic Unitary Transformation 554
14.3.2 Local Decomposition of the XOperator 555
14.3.3 Local Approximations to the ExactDecoupling Transformation 556
14.3.4 Numerical Comparison 559
14.4 Efficient Calculation of Spin–Orbit Coupling Effects 561
14.5 Relativistic Effective Core Potentials 564
15 External Electromagnetic Fields and Molecular Properties 567
15.1 FourComponent Perturbation and Response Theory 569
15.1.1 Variational Treatment 570
15.1.2 Perturbation Theory 570
15.1.3 The DiracLike OneElectron Picture 573
15.1.4 Two Types of Properties 575
15.2 Reduction to TwoComponent Form and Picture Change Artifacts 576
15.2.1 Origin of Picture Change Errors 577
15.2.2 PictureChangeFree Transformed Properties 580
15.2.3 Foldy–Wouthuysen Transformation of Properties 580
15.2.4 Breit–Pauli Hamiltonian with Electromagnetic Fields 581
15.3 Douglas–Kroll–Hess Property Transformation 582
15.3.1 The Variational DKH Scheme for Perturbing Potentials 583
15.3.2 Most General Electromagnetic Property 584
15.3.3 Perturbative Approach 587
15.3.4 Automated Generation of DKH Property Operators 592
15.3.5 Consequences for the Electron Density Distribution 593
15.3.6 DKH Perturbation Theory with Magnetic Fields 595
15.4 Magnetic Fields in Resonance Spectroscopies 595
15.4.1 The Notorious Diamagnetic Term 595
15.4.2 Gauge Origin and London Orbitals 596
15.4.3 Explicit Form of Perturbation Operators 597
15.4.4 Spin Hamiltonian 598
15.5 Electric Field Gradient and Nuclear Quadrupole Moment 599
15.6 Parity Violation and ElectroWeak Chemistry 602
16 Relativistic Effects in Chemistry 605
16.1 Effects in Atoms with Consequences for Chemical Bonding 608
16.2 Is Spin a Relativistic Effect? 612
16.3 ZDependence of Relativistic Effects: Perturbation Theory 613
16.4 Potential Energy Surfaces and Spectroscopic Parameters 614
16.4.1 Dihydrogen 616
16.4.2 Thallium Hydride 617
16.4.3 The Gold Dimer 619
16.4.4 Tin Oxide and Cesium Hydride 622
16.5 Lanthanides and Actinides 622
16.5.1 Lanthanide and Actinide Contraction 623
16.5.2 Electronic Spectra of Actinide Compounds 623
16.6 Electron Density of Transition Metal Complexes 625
16.7 Relativistic Quantum Chemical Calculations in Practice 629
Appendix 631
A Vector and Tensor Calculus 633
A.1 ThreeDimensional Expressions 633
A.1.1 Algebraic Vector and Tensor Operations 633
A.1.2 Differential Vector Operations 634
A.1.3 Integral Theorems and Distributions 635
A.1.4 Total Differentials and Time Derivatives 637
A.2 FourDimensional Expressions 638
A.2.1 Algebraic Vector and Tensor Operations 638
A.2.2 Differential Vector Operations 638
B Kinetic Energy in Generalized Coordinates 641
C Technical Proofs for Special Relativity 643
C.1 Invariance of SpaceTime Interval 643
C.2 Uniqueness of Lorentz Transformations 644
C.3 Useful Trigonometric and Hyperbolic Formulae for Lorentz Transformations 646
D Relations for Pauli and Dirac Matrices 649
D.1 Pauli Spin Matrices 649
D.2 Dirac’s Relation 650
D.2.1 Momenta and Vector Fields 651
D.2.2 FourDimensional Generalization 652
E Fourier Transformations 653
E.1 Definition and General Properties 653
E.2 Fourier Transformation of the Coulomb Potential 654
F Gordon Decomposition 657
F.1 OneElectron Case 657
F.2 ManyElectron Case 659
G Discretization and Quadrature Schemes 661
G.1 Numerov Approach toward SecondOrder Differential Equations 661
G.2 Numerov Approach for FirstOrder Differential Equations 663
G.3 Simpson’s Quadrature Formula 665
G.4 Bickley’s CentralDifference Formulae 665
H List of Abbreviations and Acronyms 667
I List of Symbols 669
J Units and Dimensions 673
References 675
Author Information
Alexander Wolf studied physics at the University of Erlangen and at Imperial College, London. In 2004, he completed his PhD in Theoretical Chemistry in the group of Bernd Artur Hess in Erlangen. His thesis elaborated on the generalized DouglasKrollHess transformation and efficient decoupling schemes for the Dirac Hamiltonian. As a postdoc he continued to work on these topics in the group of Markus Reiher at the universities of Bonn (2004) and Jena (2005). Since 2006 he has been engaged in financial risk management for various consultancies and is currently working in the area of structuring and modeling of life insurance products. On a regular basis he has been using his spare time to delve into his old passion, relativistic quantum mechanics and quantum chemistry.
New to This Edition
The new edition is updated to include the latest developments in the field. Some content of the chapters has been restructured for the sake of clarity.
A significant amount of completely new content including:
 extension of the discussion of continuum dissolution
 extended discussion of spin in relativistic density functional theory
 exactdecoupling procedures with a focus on X2C
 local approximations to exactdecoupling methods
 more than 100 new key references