Atomic orbitals, electron transfer between

The TMCs electronic wave function formalizing the CFT ionic model is one with a fixed number of electrons in the d-shell. In the EHCF method it is used as a zero approximation. The interactions responsible for electron transfers between the d-shell and the ligands are treated as perturbations. Following the standards semiempirical setting we restrict the AO basis for all atoms of the TMC by the valence orbitals. All the AOs of the TMC are... 

Outer-sphere electron transfer Electron transfer between redox centers which do not share a common atom or group, i.e., the interaction between the relevant electronic orbitals of the two centers in the transition state is weak (<20 kj mol ). Compare inner-sphere electron transfer. 

The potential surrouding each atom in a molecule is not the same as that for the free atom, because electron transfer occurs between atoms in the molecule. This means that atomic orbitals in the molecule are distinct from those in the free atom. Accordingly, it is necessary to use atomic orbitals optimized for each atomic potential in the molecule, as basis functions. In the present methods, the molecular wave functions were expressed as linear combinations of atomic orbitals obtained by numerically solving the Dirac-Slater or Hartree-Fock-Slater equations in the atomic-like potential derived from the spherical average of the molecular charge density around the nuclei [15]. Thus the atomic orbitals used as basis functions were automatically optimized for the molecule and thus the minimum size of the present basis set has enough flexibility to form accurate molecular orbitals. 

This active orbital partitioning many be continued by separating the electrons and orbitals involving the different hydrogen atoms into different subspaces. This expansion may be written as (2) (2 C(1)—H(1)) (2 C(1)— H(2)) (2 C(2)—H(3)) 2 C(2)—H(4))2(4 C(1)=C(2)) and consists of 6144 CSFs. This wavefunction is even more restrictive than the previous example and neglects expansion terms that correspond to electron transfer between the various C—H bonds, including those bonds involving the same carbon atom. 

A putative Cu -oxo species, formed from an acido-basic catalysis or from the heterolysis of the 0-0 bound of a Cu -hydroperoxo intermediate as in Eq. (23) of Fig. 15, was also proposed although its orbital populating seems unfavorable 1ST). Eqs. (24), (25) summarize the pathway that could be involved with this species during DNA oxidation events. A hydrogen atom abstraction on the DNA by the Cu -oxo species would produce a radical on DNA and a Cu -hydroxo species [Eq. (24)]. Then an eventual electron transfer between them may allow the oxidation of the radical to a cation and the regeneration of the initial Cu complex. 

The existence of numerous isomers illustrates the relative ease of electron transfer between a-orbitals (which dominate in the bonding in planar structures) and Planar structures are the most stable for n < 5, three-dimensional structures for > 5. There is a transition at n = 6 to ground states with minimum spin degeneracy, so that it is essential to incorporate spin in the calculations of lighter clusters. The structural variety is consistent with the metallic nature of the elements The valence sp-shells in the atoms are less than half-filled, and the separation in energy between the highest occupied and lowest unoccupied orbitals is usually small. 

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