Page 10 - Valence Bond Methods. Theory and Applications

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6 Spatial symmetry
98
6.1
6.2
98
Bases for spatial group algebras
6.3 The AO basis Contents 97
Constellations and configurations
99
6.3.1 Example 1. H 2 O 100
6.3.2 Example 2. NH 3 102
6.3.3 Example 3. The π system of benzene 105
7 Varieties of VB treatments 107
7.1 Local orbitals 107
7.2 Nonlocal orbitals 108
8 The physics of ionic structures 111
8.1 A silly two-electron example 111
8.2 Ionic structures and the electric moment of LiH 113
8.3 Covalent and ionic curve crossings in LiF 115
II Examples and interpetations
9 Selection of structures and arrangement of bases 121
9.1 The AO bases 121
9.2 Structure selection 123
9.2.1 N 2 and an ST¨G basis 123
9.2.2 N 2 and a 6-31G basis 123
∗
9.2.3 N 2 and a 6-31G basis 124
9.3 Planar aromatic and π systems 124
10 Four simple three-electron systems 125
10.1 The allyl radical 125
10.1.1 MCVB treatment 126
10.1.2 Example of transformation to HLSP functions 129
10.1.3 SCVB treatment with corresponding orbitals 132
+
10.2 The He ion 134
2
10.2.1 MCVB calculation 134
10.2.2 SCVB with corresponding orbitals 135
10.3 The valence orbitals of the BeH molecule 136
10.3.1 Full MCVB treatment 137
10.3.2 An SCVB treatment 139
10.4 The Li atom 141
10.4.1 SCVB treatment 142
10.4.2 MCVB treatment 144
11 Second row homonuclear diatomics 145
11.1 Atomic properties 145
11.2 Arrangement of bases and quantitative results 146