Page 11 - Valence Bond Methods. Theory and Applications

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11.3 Qualitative discussion
149
11.3.1
11.3.2
152
C 2
154
11.3.3 B 2 Contents 148
N 2
11.3.4 O 2 157
11.3.5 F 2 160
11.4 General conclusions 161
12 Second row heteronuclear diatomics 162
12.1 An ST¨G AO basis 162
12.1.1 N 2 164
12.1.2 CO 166
12.1.3 BF 168
12.1.4 BeNe 171
12.2 Quantitative results from a 6-31G basis 173
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12.3 Dipole moments of CO, BF, and BeNe 174
12.3.1 Results for 6-31G basis 174
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12.3.2 Difficulties with the ST¨G basis 175
13 Methane, ethane and hybridization 177
13.1 CH, CH 2 ,CH 3 , and CH 4 177
13.1.1 ST¨G basis 177
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13.1.2 6-31G basis 186
13.2 Ethane 187
13.3 Conclusions 189
14 Rings of hydrogen atoms 191
14.1 Basis set 192
14.2 Energy surfaces 192
15 Aromatic compounds 197
15.1 ST¨G calculation 198
15.1.1 SCVB treatment of π system 200
15.1.2 Comparison with linear 1,3,5-hexatriene 203
15.2 The 6-31G basis 205
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15.2.1 Comparison with cyclobutadiene 208
15.3 The resonance energy of benzene 208
15.4 Naphthalene with an ST¨G basis 211
15.4.1 MCVB treatment 211
15.4.2 The MOCI treatment 212
15.4.3 Conclusions 213
16 Interaction of molecular fragments 214
16.1 Methylene, ethylene, and cyclopropane 214
16.1.1 The methylene biradical 215