Electrons in dry DNA from density functional calculations |
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| Authors: | EMILIO ARTACHO MAIDER MACHADO DANIEL SÁNCHEZ-PORTAL PABLO ORDEJÓN JOSÉ M SOLER |
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| Institution: | 1. Department of Earth Sciences, Downing Street , University of Cambridge , Cambridge, CB2 3EQ, UK;2. Depto. de Física de Materiales , Universidad del País Vasco , 20080, Donostia, Spain;3. Centro Mixto CSIC-UPV/EHU and Donostia Intl. Physics Center , Po. Manuel de Lardizabal 4, 20018, Donostia, Spain;4. Institut de Ciència de Materials de Barcelona , 08193, Bellaterra, Barcelona, Spain;5. Departamento de Física de la Materia Condensada, C-III , Universidad Autónoma , 28049, Madrid, Spain |
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| Abstract: | The electronic structure of an infinite polyguanine-polycytosine DNA molecule in its dry A-helix structure is studied by means of density functional calculations. An extensive study of 30 nucleic base pairs is performed to validate the method. The electronic energy bands of DNA close to the Fermi level are then analysed in order to clarify the electron transport properties in this particularly simple DNA realization, probably the best suited candidate for conduction. The energy scale found for the relevant band widths, as compared with the energy fluctuations of vibrational or genetic-sequence origin, makes highly implausible the coherent transport of electrons in this system. The possibility of diffusive transport with subnanometre mean free paths is, however, still open. Information for model Hamiltonians for conduction is provided. |
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