Density functional theory electron transfer

Density functional theory Electron affinity Electron transfer... 

From the early advances in the quantum-chemical description of molecular electron densities [1-9] to modem approaches to the fundamental connections between experimental electron density analysis, such as crystallography [10-13] and density functional theories of electron densities [14-43], patterns of electron densities based on the theory of catastrophes and related methods [44-52], and to advances in combining theoretical and experimental conditions on electron densities [53-68], local approximations have played an important role. Considering either the formal charges in atomic regions or the representation of local electron densities in the structure refinement process, some degree of approximate transferability of at least some of the local structural features has been assumed. 

In a rigorous sense, non-transferability of molecular parts has profound implications on chemical conclusions based on electron densities. Since some of the original results on the utility and reliability of transferred electron densities have been derived within the framework of density functional theory, here we shall follow this approach, and describe a recent result on a general, holographic property of electron density fragments of complete, boundaryless molecular electron densities. 

When a molecule accepts electrons, the electrons tend to go to places where/1 (r) is large because it is at these locations that the molecule is most able to stabilize additional electrons. Therefore a molecule is susceptible to nucleophilic attack at sites where/ "(r) is large. Similarly, a molecule is susceptible to electrophilic attack at sites where f (r) is large, because these are the regions where electron removal destabilizes the molecule the least. In chemical density functional theory (DFT), the Fukui functions are the key regioselectivity indicators for electron-transfer controlled reactions. 

Recent density functional theory (DFT) calculations have been used to calculate the transfer of unpaired electron spin densities to the nearby atoms and analyze the orbitals involved in these mechanisms. For example. Figure 8 shows the spin densities obtained for Cr +-doped LiCo02. The spin densities can be calculated by subtracting the spin-up elec-... 

For oxidation of G in duplex DNA, Steenken concluded that the proton on N-1 of G shifts spontaneously to N-3 of the cytosine in the normal Watson-Crick base pair to generate [C+(H)/G ]. Consistent with this proposal, calculations indicate that charge transfer in oxidized DNA is coupled with proton transfer from G to Experiments carried out in D2O also reveal a kinetic isotope effect for G oxidation, implicating a concerted proton-coupled electron transfer mechanism. However, density functional theory (DFT) calculations in the gas phase predict that the structure with a proton on G N-1 [C/HG ] is more stable than [C (H)/G ] by 1.4kcal/mol. " ... 

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Lewis FD, Letsinger RL, Wasielewski MR (2001) Dynamics of photoinduced charge transfer and hole transport in synthetic DNA hairpins. Acc Chem Res 34 159-170 Li Z, Cai Z, Sevilla MD (2001) Investigation of proton transfer within DNA base pair anion and cation radicals by density functional theory (DFT).J Phys Chem B 105 10115-10123 Li Z, Cai Z, Sevilla MD (2002) DFT calculations on the electron affinities of nucleic acid bases dealing with negative electron affinities. J Phys Chem A 106 1596-1603 Lillicrap SC, Fielden EM (1969) Luminescence kinetics following pulse irradiation. II. DNA. J Chem Phys 51 3503-3511... 

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