Couplage électronique et transferts de charges dans l'ADN : étude du contrôle énergétique
Bibliographic record
Abstract
The influence of the energetic gap on the effective distance-decay rate of electronic coupling (βeff) in DNA is investigated in the context of the superexchange mechanism. The DNA double helix is described by a tight-binding electronic Hamiltonian model, in which all orbitals have the same energy and interact with one another through an exponentially decaying function of distance. Our numerical results concerning the βeff values obtained for two different DNA molecules are analyzed within the theoretical framework of the "continuous-medium approximation," previously developed by Lopez-Castillo et al. (J.-M. Lopez-Castillo, A. Filali-Mouhim, I.L. Plante, and J.-P. Jay-Gerin. J. Phys. Chem. 99 : 6864-6875, 1995). We find that the intervening DNA bridge between the donor and acceptor sites is defined by a unique dimensionless control parameter Γ/E, where E is the energy of the orbitals of this medium with respect to those of the redox site orbitals (energetic gap) and Γ is the electronic band width of the bridge considered as a continuous medium. In the narrow-band regime, our "through-space" coupling model predicts βeff values that are in good order of magnitude agreement with those calculated by other theoretical approaches as well as with those obtained from experiment. Moreover, under equivalent energetic conditions, the DNA-mediated transfers of holes and electrons differ considerably. This difference depends upon the sign of the parameter Γ/E.Key words: DNA, electronic coupling, effective distance-decay rate, energetic gap, superexchange mechanism, continuous-medium approximation, long-distance electron and hole transfers.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".