Homonuclear Diatomic Molecules of the Second Short Period Elements

1 Homonuclear Diatomic Molecules of the Second Short Period Elements, E  

This section consists of the formal molecular orbital treatment of homonuclear diatomic molecules of the second short period. The molec- 

The classification of the two 2s orbitals of an E2 molecule is very similar to that of the two Is orbitals of dihydrogen and is not repeated here. The two combinations of the 2s orbitals are  

The use of numerical prefixes to distinguish between orbitals of the same symmetry was suggested by Mulliken and is the generally accepted method. The prefixes may be omitted when it is clear that no ambiguity is present. 

The character of the reducible representation of the 2p orbitals of E2 molecules may be obtained by writing down, under each symmetry element of the group, the number of such orbitals which are unchanged by each symmetry operation. This produces the representation  

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