Orbital interaction theory diagram

In the language of perturbation theory, the two orbitals will constitute the unperturbed system, the perturbation is the interaction between them, and the result of the interaction is what we wish to determine. The situation is displayed in Figure 3.1a. The diagram shown in Figure 3.1 b conveys the same information in the standard representations of PMO or orbital interaction theory. The two interacting but unperturbed systems are shown on the left and the right, and the system after the interaction is turned on is displayed between them. Our task is to find out what the system looks like after the interaction. Fet us start with the two unperturbed orbitals and seek the best MOs that can be constructed from them. Thus,... 

Orbital interaction theory, 34-71 diagram, 40, 42, 47 limitations, 69-71 sigma bonds, 72-86... 

Optical purity, by NMR, 13, 14 Orbital correlation diagrams, 196-203 cycloaddition reactions, 197-196 Diels-Alder, 198 ethylene -E ethylene, 198 electrocyclic reactions, 198-200 butadienes, 199 hexatrienes, 199 limitations, 203 photochemical, 201 Woodward-Hoffinann, 197 Orbital energies, see also Energies, orbital degeneracy, 27, 90 Orbital interaction theory, 34-71 diagram, 40, 42, 47 limitations, 69-71 sigma bonds, 72-86 Orbitals... 

Use PMO theory to describe the effect of the substituents on the ionization potential. Use an MO diagram to explain the interaction of the substituents with the n bonds. Explicitly take into account the fact that the two orbitals interact and therefore cannot be treated as separate entities (see Problem 10). 

The overall results of substituent effects are observed in the products of a reaction, their rates of formation, and their stereochemistries. The purpose of this article is to apply very simple theoretical techniques to correlations and predictions of the rate and stereoselectivity effects of substituents in [2+2] photocycloadditions. The theoretical methods that will be used are perturbational molecular orbital (PMO) theory and its pictorial representation, the interaction diagram. Only an outline of the theory will be given below, since several more detailed descriptions are available. 4,18-34)... 

In MO theory the stability of these bonds is readily understood by inspection of orbital interaction diagrams 22 and 23, where 0 and o are bonding and antibonding combinations of active orbitals, respectively. Both... 

In earlier chapters, it was seen how a qualitative energy-level diagram for the smallest repeating chemical point group, or lattice point (known to crystallographers as the basis, or asymmetric unit), can be used to approximate the relative placement of the energy bands in a solid at the center of the BZ. This is so because the LCAO-MO theory is equivalent to the LCAO band scheme, minus consideration of the lattice periodicity. The present chapter will investigate how the orbital interactions vary for different values of the wave vector over the BZ. 

Molecular orbital interaction diagrams and frontier molecular orbital theory are used in an additional, more advanced level of explanation (indicated by a sidebar) that can be skipped without penalty. Also indicated are the more mathematical sections of thermodynamics and kinetics that provide support for the formulas and can be skipped. 

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