Correlation of weak and strong field approximations

For the weak field case, we have the situation where the crystal field interaction is much weaker than the electronic repulsion. In this approximation, the Russell-Saunders terms 3F, 3P, 1G, lD, and 5 for the d2 configuration are good basis functions. When the crystal field is turned on, these terms split according to the results given in Table 8.4.2  

These are the states arising from the weak field approximation. 

Correlation diagram for a d2 octahedral complex. The g subscript is omitted in all the state or orbital designations. Note that the lines connecting the triplet states constitute the Orgel diagram shown in Fig. 8.5.4 or Fig. 8.5.5. 

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