2b 1
3a 1
b 1
1b 2
ψ(B 1 )
ψ(A 1 )
h 1 ,h
1b 1
1a 1
2a 1
b 2
a 1
a 1
2p y (0)
2p x (0)
2p z (0)
2s(0)
(a)
1b 2
2a 1
1a 1
The oxygen contribution
comes largely or
entirely from 2p orbitals
Binding energy
The oxygen contribution
is largely or
entirely from the 2s orbitals
Experimental bond
angle
in H 2 O(104.5º)
Angle HOH
0º
180º
1b 1
At HOH = 180º, 2a 1 and 1b 2 become degenerate (linear triatomic)
At HOH = 0º, 1b 1 and 1b 2 become degenerate (linear triatomic)
(b)
E
Scheme 2.5 a energy level trend of the water symmetry orbitals b the same against HOH angle
amplitude. b 1 and b 2 are exchanged from (a–b)
32
2 Symmetry Orbitals for Different Bis and Polyatomic Molecules
3a 1
b 1
1b 2
ψ(B 1 )
ψ(A 1 )
h 1 ,h
1b 1
1a 1
2a 1
b 2
a 1
a 1
2p y (0)
2p x (0)
2p z (0)
2s(0)
(a)
1b 2
2a 1
1a 1
The oxygen contribution
comes largely or
entirely from 2p orbitals
Binding energy
The oxygen contribution
is largely or
entirely from the 2s orbitals
Experimental bond
angle
in H 2 O(104.5º)
Angle HOH
0º
180º
1b 1
At HOH = 180º, 2a 1 and 1b 2 become degenerate (linear triatomic)
At HOH = 0º, 1b 1 and 1b 2 become degenerate (linear triatomic)
(b)
E
Scheme 2.5 a energy level trend of the water symmetry orbitals b the same against HOH angle
amplitude. b 1 and b 2 are exchanged from (a–b)
32
2 Symmetry Orbitals for Different Bis and Polyatomic Molecules