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A field says which part of the subject an essay sits in and a series follows one idea in depth. This is the third axis: the named objects themselves, and every essay that touches each one.
There are 366 named objects here, and 306 of them are named by more than one essay. Those have a page of their own. The rest link straight to the single essay that names them — a page whose whole content is one card would say nothing the essay itself does not.
- Absorption 3 essays
- Adjacency matrix 6 essays
- Amplitude 1 essay
- Angular momentum 9 essays
- Angular node 3 essays
- Angular overlap 10 essays
- Anharmonicity 3 essays
- Antiaromaticity 8 essays
- Antibonding 15 essays
- Approximation 95 essays
- Aromaticity 14 essays
- Avoided crossing 5 essays
- Axial 7 essays
- Back-bonding 5 essays
- Back-donation 4 essays
- Band edge 13 essays
- Band filling 9 essays
- Band gap 24 essays
- Band structure 1 essay
- Band width 13 essays
- Bands in a solid 33 essays
- Barycentre 4 essays
- Basis 37 essays
- Basis set 7 essays
- Basis set superposition 3 essays
- Basis set superposition error 6 essays
- Bent bond 3 essays
- Bent's rule 6 essays
- Benzene 11 essays
- Bipartite 2 essays
- Boltzmann 6 essays
- Boltzmann distribution 3 essays
- Bond alternation 16 essays
- Bond angle 22 essays
- Bond dipole 10 essays
- Bond energy 3 essays
- Bond length 27 essays
- Bond order 28 essays
- Bonding 8 essays
- Born–Oppenheimer separation 8 essays
- Canonical orbitals 14 essays
- Centrifugal distortion 1 essay
- Character table 27 essays
- Charge density 10 essays
- Charge gap 1 essay
- Charge transfer 6 essays
- Chemical hardness 5 essays
- Chemical potential 2 essays
- Chirality 7 essays
- Closed form 89 essays
- Closed-shell configurations 25 essays
- Closure 5 essays
- Cluster 7 essays
- Coherence length 3 essays
- Cohesion 13 essays
- Cohesive energy 1 essay
- Composite method 2 essays
- Concentration 1 essay
- Conditioning 4 essays
- Conductivity 3 essays
- Configuration interaction 6 essays
- Conformation 8 essays
- Conformer 6 essays
- Conjugacy class 6 essays
- Conjugation 15 essays
- Conserved quantity 3 essays
- Contour level 15 essays
- Contraction 1 essay
- Convention 111 essays
- Convergence 33 essays
- Coordination 7 essays
- Coordination complex 12 essays
- Coordination number 25 essays
- Correlation 5 essays
- Correlation energy 13 essays
- Counterpoise 6 essays
- Covalent bonding 3 essays
- Critical exponent 3 essays
- Crossover 2 essays
- Crystal field 4 essays
- D d transition 4 essays
- d orbitals 31 essays
- Dangling bond 1 essay
- Defect 4 essays
- Defect level 1 essay
- Defect state 9 essays
- Degeneracy 114 essays
- Delocalisation 31 essays
- Density matrix 7 essays
- Density of states 17 essays
- Depolarisation ratio 6 essays
- Descent in symmetry 4 essays
- Dimension 1 essay
- Dipole 1 essay
- Dipole interaction 1 essay
- Dipole moment 21 essays
- Disorder 10 essays
- Dispersion 1 essay
- Dissociation 3 essays
- Distortion 11 essays
- Doping 6 essays
- Double occupancy 12 essays
- Double well 7 essays
- Effective nuclear charge 26 essays
- Eigenvalue 54 essays
- Eigenvector 13 essays
- Eighteen-electron rule 7 essays
- Elastic energy 13 essays
- Electron affinity 11 essays
- Electron correlation 30 essays
- Electron count 26 essays
- Electron domain 1 essay
- Electron hole symmetry 1 essay
- Electron-deficient bonding 12 essays
- Electronegativity 35 essays
- Empirical scale 7 essays
- Enantiomer 1 essay
- Enclosed probability 12 essays
- Energy per site 11 essays
- Equatorial 6 essays
- Equivalent atoms 9 essays
- Error cancellation 2 essays
- Error propagation 8 essays
- Exact diagonalisation 46 essays
- Exchange coupling 11 essays
- Excitation 2 essays
- Expectation value 28 essays
- Extrapolation 6 essays
- Fermi level 4 essays
- Filling 16 essays
- Finite-size effect 4 essays
- Fluxionality 2 essays
- Force constant 23 essays
- Fragment method 5 essays
- Franck–Condon principle 3 essays
- Free energy 2 essays
- Frustration 3 essays
- Gaussian 4 essays
- Gaussian basis 3 essays
- Gem-dimethyl effect 1 essay
- Graph 18 essays
- Group order 17 essays
- Hardness 6 essays
- Harmonic approximation 19 essays
- Hartree–Fock 11 essays
- Heteroatom 4 essays
- High-spin 3 essays
- HOMO–LUMO gap 17 essays
- Hubbard model 31 essays
- Hückel theory 40 essays
- Hückel's 4n+2 rule 7 essays
- Hund's rule 1 essay
- Hybrid orbital 5 essays
- Hybridisation 12 essays
- Hypervalency 17 essays
- Improper rotation 6 essays
- Infrared activity 9 essays
- Insulator 7 essays
- Intermolecular force 10 essays
- Internal coordinate 18 essays
- Inversion splitting 8 essays
- Ionic bonding 4 essays
- Ionic radius 8 essays
- Ionisation energy 28 essays
- Irreducible representations 53 essays
- Isosurface 8 essays
- Isotope substitution 10 essays
- Isotopologue 15 essays
- Jahn–Teller distortion 11 essays
- Koopmans theorem 7 essays
- Koopmans' theorem 5 essays
- Laporte's rule 2 essays
- Lattice energy 3 essays
- Least-squares 47 essays
- Level spacing 12 essays
- Ligand field 38 essays
- Linear dependence 1 essay
- Local minimum 24 essays
- Local symmetry 1 essay
- Localisation 35 essays
- Lone pair 19 essays
- Long-range interaction 9 essays
- Low spin 2 essays
- Löwdin orthogonalisation 4 essays
- Madelung constant 1 essay
- Magnetic moment 14 essays
- Magnetic susceptibility 6 essays
- Magnetism 4 essays
- Many-body expansion 6 essays
- Many-electron wavefunctions 24 essays
- Matrix element 14 essays
- Mean-field approximation 3 essays
- Measurement uncertainty 7 essays
- Melting point 1 essay
- Meso compounds 1 essay
- Metal 11 essays
- Minimisation 15 essays
- Mode composition 8 essays
- Model limit 246 essays
- Model selection 4 essays
- Modulation 1 essay
- Molecular orbital 31 essays
- Moment 1 essay
- Moment of inertia 15 essays
- Momentum 1 essay
- Momentum orbital 4 essays
- Monotonicity 4 essays
- Morse potential 3 essays
- Most probable radius 3 essays
- Mott insulator 1 essay
- Mulliken scale 8 essays
- Multicentre bonding 19 essays
- Multireference 3 essays
- Naphthalene 1 essay
- Natural occupation 1 essay
- Nodal plane 1 essay
- Node 10 essays
- Non-bonding orbitals 19 essays
- Normal mode 33 essays
- Normalisation 6 essays
- Numerical precision 5 essays
- Observable 5 essays
- Octet 3 essays
- Octet rule 8 essays
- On-site repulsion 23 essays
- One-electron approximation 1 essay
- One-electron models 42 essays
- Open-shell configurations 9 essays
- Orbit (group theory) 7 essays
- Orbital 1 essay
- Orbital approximation 4 essays
- Order parameter 1 essay
- Orthogonality 14 essays
- Overlap 8 essays
- Overlap integral 49 essays
- Oxidation state 1 essay
- Pair distribution 1 essay
- Pairing energy 3 essays
- Parity (g and u) 5 essays
- Partial charge 29 essays
- Participation ratio 11 essays
- Pauling scale 9 essays
- Peierls distortion 18 essays
- Penetration 6 essays
- Periodic trend 2 essays
- Perturbation 11 essays
- Perturbation theory 13 essays
- Photoelectron 1 essay
- Photoelectron spectroscopy 12 essays
- Photoelectron spectrum 11 essays
- Pi acceptor 11 essays
- Pi bond 1 essay
- Pi-donor 8 essays
- Point group 49 essays
- Polarisability 7 essays
- Polarity 18 essays
- Polyene 3 essays
- Predictor 6 essays
- Principal axes 1 essay
- Probability density 25 essays
- Product rule 1 essay
- Projector 1 essay
- Quadrature 11 essays
- Quantum defect 6 essays
- Quantum numbers 11 essays
- Radial distribution 10 essays
- Radial moment 3 essays
- Radial node 7 essays
- Raman activity 10 essays
- Raman spectroscopy 3 essays
- Rank correlation 14 essays
- Reduced mass 19 essays
- Reduction formula 27 essays
- Reference state 62 essays
- Relaxation 4 essays
- Repulsion 15 essays
- Resonance 5 essays
- Rigid-rotor 7 essays
- Ring current 5 essays
- Ring strain 10 essays
- Rotamer 6 essays
- Rotation group 1 essay
- Rotational constant 13 essays
- Round-trip checks 6 essays
- s character 9 essays
- Satellite 4 essays
- Scaling 3 essays
- Schoenflies symbols 3 essays
- Screening 8 essays
- Second moment 10 essays
- Selection rules 27 essays
- Self-consistency 2 essays
- Shell closure 10 essays
- Shell vector 1 essay
- Shielding 8 essays
- Sigma bond 1 essay
- Sign 1 essay
- Sign change 4 essays
- Silent mode 3 essays
- Site symmetry 2 essays
- sp³ hybrids 6 essays
- Spectral moments 2 essays
- Spectral weight 3 essays
- Spectrochemical series 8 essays
- Spectrum 1 essay
- Spherical harmonics 4 essays
- Spin state 10 essays
- Spin-only 3 essays
- Spin-orbit 2 essays
- Splitting 14 essays
- Square antiprism 1 essay
- Stabiliser (group theory) 4 essays
- Stark effect 7 essays
- Stereocentre 1 essay
- Structure 8 essays
- Subgroup 5 essays
- Sublattice 1 essay
- Substituent effect 1 essay
- Sum rule 1 essay
- Superexchange 2 essays
- Surface 4 essays
- Surface energy 1 essay
- Susceptibility 5 essays
- Symmetric top 5 essays
- Symmetry breaking 32 essays
- Symmetry operation 49 essays
- Symmetry-forbidden transitions 13 essays
- Temperature 11 essays
- Tetrahedral angle 9 essays
- the aufbau principle 5 essays
- The rule of mutual exclusion 6 essays
- Thermodynamic limit 24 essays
- Thomson problem 3 essays
- Three-centre bonding 17 essays
- Threshold 7 essays
- Tight-binding models 43 essays
- Torsion 6 essays
- Trace 4 essays
- Trans influence 1 essay
- Transferability 2 essays
- Transition moment 9 essays
- Trigonal bipyramid 5 essays
- Tunnelling 7 essays
- Two-centre bonding 6 essays
- Umbrella mode 5 essays
- Underdetermination 55 essays
- Unitary transformation 19 essays
- Unpaired electrons 11 essays
- Vacancy 1 essay
- Valence 2 essays
- Valence bond 5 essays
- Valence force field 13 essays
- Variational 10 essays
- Variational principle 4 essays
- Vibration 2 essays
- Vibrational modes 33 essays
- Virial theorem 3 essays
- VSEPR 13 essays
- Wavefunction 16 essays
- Wavenumber 8 essays
- Wavevector 1 essay
- Zeeman effect 3 essays
- Zero mode 5 essays
- Zero-point energy 14 essays
- π systems 10 essays
- σ bonding 7 essays