Electronegativity, orbital

To become familar with the algorithm for charge calculation by partial equalization of orbital electronegativity (PEOE) and by a modified Hiickel Molecular Orbital method... 

At the outset of the Partial Equalization of Orbital Electronegativities (PEOE) method [28] is the electronegativity concept in the form of Eq. (11) presented by Mulliken, who put it on a sound theoretical basis [29]. 

In this equation, the electronegativity of an atom is related to its ionization potential, 1, and its electron affinity, E. Mulhken already pointed out that in this definition the ionization potential, and the electron affinity, E, of valence states have to be used. This idea was further elaborated by Hinze et al. [30, 31], who introduced the concept of orbital electronegativity. 

The electronegativity of an atom further depends on the charge in this orbital and also on the charge in the other orbitals of this atom. For this dependence of orbital electronegativity on the total charge, Q, irrespective of whether part of it resides in the orbital considered or in the other orbitals of this atom, we selected a polynomial of degree two (Eq. (12)). 

Table 7.5. Parameters for the dependence of orbital electronegativity on charge (Eq. (12)),...

Figure 7-4. The procedure for Partial Equalization of Orbital Electronegativities (PEOE).

The PEOE method leads to only partial equalization of orbital electronegativities. Thus, each atom of a molecule retains, on the basis of Eq. (12), a residual electronegativity that measures its potential to attract further electrons. It has been shown that the values of residual electronegativities can be taken as a quantitative measure of the inductive effect [35]. 

Gasteiger J and M Marsili 1980. Iterative Partial Equalization of Orbital Electronegativity - Rapid Access to Atomic Charges. Tetrahedron 36 3219-3288. 

Molecular Orbital Electronegativity as Electron Chemical Potential in Semiempirical SCF Schemes... 

MOLECULAR ORBITAL ELECTRONEGATIVITY AS ELECTRON CHEMICAL POTENTIAL... 

Gasteiger, J., Marsili, M. Iterative partial equalization of orbital electronegativity - a rapid access to atomic charges. Tetrahedron 1980, 36, 3219-3228. 

Grant, J. A., R. L. Williams, and H. A. Scheraga. 1990. Ab Initio Self-Consistent Field and Potential-Dependent Partial Equalization of Orbital Electronegativity Calculations of Hydration Properties of N-Acetyl-N -Methyl-Alanineamide. Biopolymers 30, 929-949. 

No, K. T., J. A. Grant, M. S. Jhon, andH. A. Scheraga. 1990. Determination of Net Atomic Charges Using a Modified Partial Equalization of Orbital Electronegativity Method. 2. Application to Ionic and Aromatic Molecules as Models for Polypeptides, J. Phys. Chem. 94, 4740-4746. 

An empirical relation between band gap and Zunger s orbital electronegativity in s/ -bonded compounds has been determined by Makino (1994a) using a formula derived from the bond orbital model. Based on the bond orbital model and Zunger s orbital electronegativity, new structural maps of AB, AB2 and AB3 compounds between transition metals have been successfully constructed (Makino 1994b). 

MPFOF Modified partial equalization of orbital electronegativity... 

Pople argued that this would better account for the tendency of an atomic orbital to both lose and gain electrons and hence "would better represent the departure of an atom from neutrality in a molecular environment . The value of the orbital electronegativity i (I+A) is determined, as described above, from appropriate spectroscopic data. 

He then deduces the following relationships between i (1 +A), the orbital electronegativity, and Ui( ... 

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