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Charge transport in desolvated DNA
Mario Wolter1, Marcus Elstner, Tomáš Kubař
1Institute of Physical Chemistry, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany.
The Journal of Chemical Physics
|October 5, 2013
Summary
DNA conductivity in molecular junctions is surprisingly unaffected by bulk solvent removal. The nearest hydration shells, not overall solvation, dictate DNA charge transport properties and electronic states.
Area of Science:
- Molecular Biophysics
- Condensed Matter Physics
- Computational Chemistry
Background:
- DNA conductivity is typically measured in dry conditions, leaving ambiguity about solvent's role.
- Understanding solvent effects on DNA structure, electronic states, and charge transport is crucial.
Purpose of the Study:
- To investigate the impact of solvent removal on DNA conductivity in molecular junctions.
- To elucidate the relationship between DNA hydration, electronic structure, and charge transport.
Main Methods:
- Classical Molecular Dynamics (MD) simulations to model DNA solvation.
- Density Functional Theory (DFT) to determine electronic structure.
- Mapping DFT to a tight-binding Hamiltonian.
- Snapshot-averaged Landauer's approach for conductivity estimation.
Main Results:
- DNA is unstable without any solvent, but micro-hydrated DNA shows conductivity similar to fully solvated DNA.
- Charge transport properties are primarily determined by the nearest hydration shell(s).
- Removal of bulk solvent has minimal impact on DNA charge transport.
Conclusions:
- The nearest hydration shells are critical for DNA charge transport, not extensive solvation.
- Experimental probing of DNA conductivity under dry conditions may still yield relevant insights.
- This work clarifies the role of hydration in DNA electronic properties.
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