Linear H3, HF, and the Three-Orbital Problem

An example shows the application of some of the ideas introduced above. Let us start with a simple three-orbital problem in which two orbitals on A interact with one on B as when the orbitals of linear H3 are constructed from those of H2+ H (3.8). 

Derivation of the molecular orbital diagram for linear H3 from that of H2 plus H. 

It is diagrammatically shown by 3.9. It is important to recall that these mixing 

The interaction with is destabilizing 0), and that with is stabilizing 

The term is positive from Table 3.1, and tjj,. is negative since e — e 0. A diagrammatic representation of is shown in 3.11. Notice again that the second- 

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