Page 183 - Valence Bond Methods. Theory and Applications

12 Second row heteronuclear diatomics
166
Tablà 12.4˜N 2 : EGSO weights (standard tableaux functions) for spherical AOs,
upper group, and s–p hybrids, lower groupŁ These are weights forwholà
symmetry functions rather thał individual tableauxŁ It should be recalled
from Chapter 6 that the detailed forms of symmetry functions are
dependent oł the particular arrangement of the orbitals ił
the tableaux and are frequently nonintuitive.
1 2 3 4
Num. 4 2 6 4
       
2s a 2s a 2s a 2s a 2s a 2s a 2s a 2s a
 2s b 2s b   2s b 2s b   2p zb 2p zb   2p za 2p za 
STF  2p xa   2p za   2p xa   2p xa 




 2p za
 2p xa
 2p xa
 2p xa
       
2p za 2p zb 2p xa 2p xb 2s b 2p za 2p yb 2p yb
2p ya 2p yb 2p ya 2p yb 2p ya 2p yb 2s b 2p zb
Wt 0.558 62 0.200 53 0.066 58 0.040 89
Num. 4 2 6 2
       
h oa h oa h oa h oa h oa h oa h oa h oa
 h ob h ob   h ob h ob   h ia h ia   h ob h ob 
STF  2p xa   h ia   2p yb   2p xa 




 2p xa
 2p xa
 h ia
 2p yb
       
h ia h ib 2p xa 2p xb h ob h ib 2p yb 2p yb
2p ya 2p yb 2p ya 2p yb 2p xa 2p xb h ia h ib
Wt 0.611 66 0.156 66 0.057 14 0.038 70
with thà hybri orbitals. In this casà thà standard tableaux function
 
h oa h oa
h ob
 h ob 
 
h ia h ib
 
 
 
2p xa 2p xb
2p ya 2p yb
hasałEGSOweightof0.005 32,rathersmallerthałthàvaluàiłthàcasàofspherical
functions. Thà reader shoul not find thesà small contributions too unexpected. Thà
ioniŁ structures singled out by thà EGSO cał bà looked at as one-third ioniŁ and
two-thirds covalent. When thà orthogonalization inherent ił thà method works, thà
effect of thà purely covalent functions is considerably depressed and is already
taken care of by thà mixed functions.
12.1.2 CO
Thà set of tables wà give for CO follðws thà pattern given for N ił thà last section.
2
Tablà 12.5 shðws thà fouw most important structures ił thà wave function of CO