P-molecular orbitals

Pople, J. A., Santry, D. P. . Molecular Orbital Theory of Nuclear Spin Coupling Constants. Mol. Phys. 8, 1 (1964). 

The six overlapping p orbitals overlap to form a set of six p molecular orbitals. Six tt electrons are completely delocalized around the ring, and... 

Lynam, M.M., Kuty, M., Damborsky, J., Koca, J., and Adriaens, P., Molecular orbital calculations to describe microbial reductive dechlorination of polychlorinated dioxins, Environ. Toxicol. Chem., 17, 988-997, 1998. 

Molecular orbitals fill in a prescribed sequence, although the sequence can vary based on the degree of interaction between s and p molecular orbitals (but you don t actually need to know any details about this). 

Figure 9-3 Production of a-jp (j p molecular orbitals by ovenap of 2p orbitals on two atoms.

Elcb 2-step, base-induced p- molecular orbital... 

Two electrons occupy the antibonding p molecular orbital singly as predicted by Hund s rule. 

In Figure 1.17 a chain of 61 CH groups is considered. Each group contributes one p molecular orbital to the TT-electron system. There are 61 states per spin quantum number 1 at midgap, 30 in the valence and 30 in the conduction band. All valence states are occupied, all conduction states are empty, and the midgap state is occupied with one electron. Consequently, it is electrically neutral and carries a magnetic moment. 

When the 2p orbitals overlap along their axes, they form o-jp and <7 p molecular orbitals.When they overlap sideways, they form TTjp and ir p molecular orbitals. 

Fig. 17.6 The p molecular orbitals of benzene. The size of the circles approximately show the, magnitude of the coefficient of the molecular orbital at each atom.

The factor 3 comes from the fact that one should consider also the three possibilities for the first index (here A). Furthermore, one must consider a and P molecular orbitals separately (i,j,k denote molecular orbitals where all are either a molecular orbitals or p). For restricted closed shell molecules, both terms in square brackets are obviously the same. More in general for k centers, the multicenter index is given as ... 

Symmetry properties of p-molecular orbitals of some important systems are discussed below ... 

In a molecular orbital picture where P and are interacting in the P" "- state, it would appear that the electron is removed from a dimer molecular orbital comprised primarily of a P molecular orbital. This could arise from inequivalent protein environments and/or conformations of P and Pm which could result in slightly different redox orbital energies for these molecules. It is difficult to assess the relative magnitudes of the coefficients of the dimer redox orbital, but if we assume that the observed magnitude of the shift of the keto carbonyl (+26 cm for P as compared to +32 cm"l for the monomer) is proportional to the hole density, it may be estimated that the orbital of Pt contributes ca. 80% to the dimer orbital. The absence or weakness of any contributions may be explained by a difference in resonance Raman scattering cross sections of the Pl+ and P]yj species at 1064 nm. 

---