Hybrid hops

Incorporation of an artificial flavin nucleobase and of a cyclobutane pyrimidine dimer building block into DNA DNA double strands, DNArPNA hybrid duplexes, and DNA-hairpins, provided compelling evidence that an excess electron can hop through DNA to initiate dimer repair even at a remote site. The maximum excess electron transfer distance realised so far in these defined Donor-DNA-Acceptor systems is 24 A. New experiments are now in progress to clarify whether even larger transfer distances can be achieved. 

The combination of metal/ligand variation in these hybrids not only allows alteration of the ET energetics but also provides a means to study mechanistic questions, such as whether ET is direct or involves a hopping mechanism. 

The benefit of a hybrid phase for the intercalation-deintercalation of mobile species such as Li+ cations is well illustrated by the study of conductive polymers such as polyaniline or polypyrrole intercalated into a V2O5 framework as potential electrode materials in lithium batteries [34]. For PANI/V2O5, an oxidative post-treatment performed under an oxygen atmosphere allowed the authors to compare the conductivity attributed to the polymer, as in absence of reduced cations, there was no electronic hopping between ions, and the conductive state was due only to the... 

Here e(fe) and V(k) are Fourier components of the hopping t j and the hybridization T. All energies in (6) are counted from p. Due to the relations (4) the problem of calculation of all electron GFs reduces to the calculation of d-electron GF with strong Coulomb interaction. 

Here indexes a = 1,2 numerate spinor components. Because we ignore direct hopping of d-electrons on the lattice, in the Hamiltonian (10) a quadratic term with the A -operators is absent, and A -operators enter linearly via the hybridization term. However in the second order perturbation with respect to hybridization such a term should appear it describes the induced hopping on the lattice. 

The concept of making hybrid monolayers to isolate single molecules was later adopted by Blum and coworkers [29, 63] to compare the conductivity of an isolated OPE molecule (95) to that of crystalline SAMs of identical OPE molecules. The reported gap resistances were almost identical, which indicated that electron transport in the molecular junction occurred through individual molecules, even in crystalline self-assembled monolayers, as opposed to through intermole-cular electron hopping. 

Hopping and hybridization terms introduce strong coupling between the QE, stripon and spinon fields, which is expressed by a coupling Hamiltonian of the form (for p-type cuprates) ... 

The EIS response depends on the flhn thickness and morphology, applied potential, and, obviously, the nature of the components of the hybrid system. The hydro-phobic nature of the polymer, the level of doping within the film, and the size of ions in contact with the polymer surface are factors to be considered for studying the response of such materials. In short, the kinetics of the overall charge transfer process should take into account (1) electron hopping between adjacent redox sites (Andrieux et al., 1986) usually described in terms of a Warburg diffusion impedance element (Nieto and Tucceri, 1996) and (2) double-layer charging at the metal-flhn interface, represented in terms of a double-layer capacitance element. 

Figure 2. The time-averaged structure of disordered hydrogen bond (compare Fig. 1). Two half-occupied sites of the H-atom have been shown. The electronic structure of the oxygen atoms is repeatedly switched between sp and sp hybridizations, following the H-hopping. The two hydro-gen-bonded groups are symmetry-related, and the O-H- - -O angle(s) are bent from ideal 180° to satisfy the boundary conditions required by the coexistence of different R-O-H and H- - -O-R angles (of 109° and 120°, respectively, in this drawing).

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