Index
245
Multiferroic, 95
Multireference, 121, 127
N
Neél state, 210, 211
Neutral determinant, 64, 124, 144, 145, 149,
162, 165, 174, 181
Non-Hund state, 77, 160, 162, 164, 165, 186
Noodleman equation, 135
O
On-site repulsion (U), 143, 145, 156, 166,
168, 177
Open-shell singlet, 60, 120
Orbital ordering, 199
Orbitals, 1
active, 61, 68, 121, 142, 147
antibonding, 60, 63, 66, 110, 180
barred, 6
bonding, 60, 61, 63, 66, 110, 180
degenerate, 65
delocalized, 60, 62–64, 101
empty, 129, 178, 179, 198–200
energies, 26, 109, 110, 119
filled, 178, 198, 200, 201
gerade/ungerade, 114, 118, 142, 147,
174, 180
half-filled, 198–201, 203
inactive, 121, 124, 125, 178, 179
localized, 62–66, 101, 108, 109, 111, 142
magnetic, 60, 67, 68, 106, 107, 119, 158,
159, 177, 180
molecular, 59, 62, 108, 109, 121
molecular orbital theory, 1
nonorthogonal, 66, 67, 105, 108, 133,
134
orbital moment, 33–35, 37–40, 43, 48, 49
orbital moment quenching, 39
spin orbital, 6, 131, 158, 193
state-specific, 152
virtual, 121, 124, 125
P
Partition function, 83
Periodic boundaries, 79, 210
Periodic calculation, 193
Permutation operator, 3, 91, 106
Perturbation operator, 22, 25, 40, 127
Perturbation theory, 21, 36, 40, 48
(un)contracted first order wave function,
130
CASPT2, 123, 127, 131, 151
Møller-Plesset, 21, 25, 127, 197
NEVPT2, 127, 129, 131, 151
quasi-degenerate, 21, 27, 124, 144–146,
148, 166, 168, 201
Rayleigh-Schrödinger, 21, 31
zeroth order Hamiltonian, 22, 25, 127,
129
Post HF, 196
Projection operator, 9, 10, 29
R
Renormalization group theory, 82
Restricted ensemble Kohn–Sham (REKS)
DFT, 136
Restricted open-shell Kohn–Sham (ROKS)
DFT, 136, 157
Rhombic magnetic anisotropy (E), 41, 54, 98
Ring exchange, 90, 91, 95, 159, 166, 168,
172, 175, 193
Robin and Day classification, 177
Russell-Saunders, 36, 39
S
Scalar relativistic effects, 36
Semi covalent exchange, 198–201
Shift operators, see ladder operators
Slater determinant, 1, 3, 7, 8, 21, 59, 65, 66,
120, 121
Slater-Condon rules, 3, 25, 62, 125, 179, 184
Spectral decomposition, 29
Spin contamination, 20, 132, 137, 174
Spin density, 111
Spin eigenfunction, 8
by diagonalization, 10
by projection, 9
genealogical approach, 12
Spin-flip DFT, 137
Spin multiplicity, 35
Spin-orbit coupling, 34, 36, 40, 41, 48
Spin polarization, 132, 148, 156–158
Spin wave, 209, 211
Step-up/step-down operators, see ladder
operators
Strong overlap limit, 133, 136
Superexchange, 67, 68, 147, 182, 197–200,
203
T
Through-bond interaction, 80
Through-space interaction, 80
245
Multiferroic, 95
Multireference, 121, 127
N
Neél state, 210, 211
Neutral determinant, 64, 124, 144, 145, 149,
162, 165, 174, 181
Non-Hund state, 77, 160, 162, 164, 165, 186
Noodleman equation, 135
O
On-site repulsion (U), 143, 145, 156, 166,
168, 177
Open-shell singlet, 60, 120
Orbital ordering, 199
Orbitals, 1
active, 61, 68, 121, 142, 147
antibonding, 60, 63, 66, 110, 180
barred, 6
bonding, 60, 61, 63, 66, 110, 180
degenerate, 65
delocalized, 60, 62–64, 101
empty, 129, 178, 179, 198–200
energies, 26, 109, 110, 119
filled, 178, 198, 200, 201
gerade/ungerade, 114, 118, 142, 147,
174, 180
half-filled, 198–201, 203
inactive, 121, 124, 125, 178, 179
localized, 62–66, 101, 108, 109, 111, 142
magnetic, 60, 67, 68, 106, 107, 119, 158,
159, 177, 180
molecular, 59, 62, 108, 109, 121
molecular orbital theory, 1
nonorthogonal, 66, 67, 105, 108, 133,
134
orbital moment, 33–35, 37–40, 43, 48, 49
orbital moment quenching, 39
spin orbital, 6, 131, 158, 193
state-specific, 152
virtual, 121, 124, 125
P
Partition function, 83
Periodic boundaries, 79, 210
Periodic calculation, 193
Permutation operator, 3, 91, 106
Perturbation operator, 22, 25, 40, 127
Perturbation theory, 21, 36, 40, 48
(un)contracted first order wave function,
130
CASPT2, 123, 127, 131, 151
Møller-Plesset, 21, 25, 127, 197
NEVPT2, 127, 129, 131, 151
quasi-degenerate, 21, 27, 124, 144–146,
148, 166, 168, 201
Rayleigh-Schrödinger, 21, 31
zeroth order Hamiltonian, 22, 25, 127,
129
Post HF, 196
Projection operator, 9, 10, 29
R
Renormalization group theory, 82
Restricted ensemble Kohn–Sham (REKS)
DFT, 136
Restricted open-shell Kohn–Sham (ROKS)
DFT, 136, 157
Rhombic magnetic anisotropy (E), 41, 54, 98
Ring exchange, 90, 91, 95, 159, 166, 168,
172, 175, 193
Robin and Day classification, 177
Russell-Saunders, 36, 39
S
Scalar relativistic effects, 36
Semi covalent exchange, 198–201
Shift operators, see ladder operators
Slater determinant, 1, 3, 7, 8, 21, 59, 65, 66,
120, 121
Slater-Condon rules, 3, 25, 62, 125, 179, 184
Spectral decomposition, 29
Spin contamination, 20, 132, 137, 174
Spin density, 111
Spin eigenfunction, 8
by diagonalization, 10
by projection, 9
genealogical approach, 12
Spin-flip DFT, 137
Spin multiplicity, 35
Spin-orbit coupling, 34, 36, 40, 41, 48
Spin polarization, 132, 148, 156–158
Spin wave, 209, 211
Step-up/step-down operators, see ladder
operators
Strong overlap limit, 133, 136
Superexchange, 67, 68, 147, 182, 197–200,
203
T
Through-bond interaction, 80
Through-space interaction, 80