Electron repulsion magnitude

As noted above, many integrals describing electron repulsion are very small in magnitude, especially those such as 4> (1)< jv(1) when p v. The simplest semi-empirical approach, termed the zero-differential overlap (ZDO) approximation, is therefore to assume that these integrals can be ignored. Mathematically expressed, this is equivalent to the following ... 

The band description ignores correlations between electrons that result from the electron-electron repulsive interaction. Alternatively stated, the band description ignores the attractive Coulomb interaction between electrons in the TT -band and holes in the ir-band. This attraction causes the formation of excitons i.e. neutral electron-hole bound states. One of the fundamental unresolved issues of the physics of semiconducting polymers is the magnitude of the exciton binding energy (see Section V-B). 

The potential F(l, 2) is the total interaction energy between the two atoms, and includes contributions from electron-nuclear attraction terms as well as from electron-electron repulsion effects. As a result Xfls, Is ) is negative, and is primarily responsible for the stability of the H-H bond. Central to this description is the fact that the wavefunctions of the participating atoms, and overlap. The magnitude of K ls , Is,), and consequently the strength of the covalent bond, is determined by the degree of non-orthogonality between the two orbitals. 

The ease of hydrolysis of ATP is partially explained by the electronic repulsions between the phosphate groups. The positive magnesium ion coordinates with these negatives charges, thus reducing their magnitude and therefore the repulsion between them. 

Electrons in the partly filled orbitals of a metal ion repel one another and give rise to a number of energy levels depending upon the arrangement of these electrons in the d-orbitals. The energy of each of these levels can be expressed in terms of some inter-electronic repulsion parameters. It is observed experimentally that magnitude of these inter-electronic repulsion parameters always decreases on the Transition Elements... 

The magnitude of inter-electronic repulsion is inversely proportional to the distance r between the regions of maximum charge density of d-orbitals which are occupied by electrons. This repulsion would decrease only if the distance r increases or the lobes of d-orbitals extend in space. The extend on ofthe lobes of the af-orbitals which means the expansion of d-electron charge cloud is known as nephelauxetic effect. Thus in the complex the electron charge cloud is more diffuse than in the free ion, hence, the average electron-electron distance is greater in the complex. 

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