3A 1 ¼ Àu 1 þ u 5 þ u 6 þ u 7 À u 4
4A 1 ¼ Àu 1 þ u 5 þ u 6 þ u 7 þ u 4
2E x ¼ 2u 5 þ u 6 þ u 7 À u 2
2E y ¼ u 3 À u 6 þ u 7
2e x
2e y
The Scheme 2.7 reports the energy level trends of ammonia for different possible
symmetries. The stabilization of 3a 1 energy level in C 3v symmetry, due to interaction with the ground state, is responsible for the stability of the pyramidal C 3v
structure.
2e′
2b 2
2p
2s
E
1s
3a′ 1
3a 1
3a 1
1b 2
1e′
1e
1a″ 2
2a′ 1
2a 1
2a 1
2e
4a 1
5a 1
4a 1
1b 1
N
D 3h
C3v
C2v
3H
Scheme 2.7 Energy level
trend of NH 3 symmetry
orbitals
2.3 Ammonia Molecule, as Example of Tetratomic Molecule
35
4A 1 ¼ Àu 1 þ u 5 þ u 6 þ u 7 þ u 4
2E x ¼ 2u 5 þ u 6 þ u 7 À u 2
2E y ¼ u 3 À u 6 þ u 7
2e x
2e y
The Scheme 2.7 reports the energy level trends of ammonia for different possible
symmetries. The stabilization of 3a 1 energy level in C 3v symmetry, due to interaction with the ground state, is responsible for the stability of the pyramidal C 3v
structure.
2e′
2b 2
2p
2s
E
1s
3a′ 1
3a 1
3a 1
1b 2
1e′
1e
1a″ 2
2a′ 1
2a 1
2a 1
2e
4a 1
5a 1
4a 1
1b 1
N
D 3h
C3v
C2v
3H
Scheme 2.7 Energy level
trend of NH 3 symmetry
orbitals
2.3 Ammonia Molecule, as Example of Tetratomic Molecule
35