Estimates of electronic coupling for excess electron transfer in DNA

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dc.contributor.author Voityuk, Alexander A.
dc.date.issued 2005
dc.identifier.citation Voityuk, Alexander A. (2005). Estimates of electronic coupling for excess electron transfer in DNA. Journal of Chemical Physics, 123 (3), 1-5. Recuperat 23 desembre 2010, a http://link.aip.org/link/JCPSA6/v123/i3/p034903/s1
dc.identifier.issn 0021-9606 (versió paper)
dc.identifier.issn 1089-7690 (versió electrònica)
dc.identifier.uri http://hdl.handle.net/10256/3196
dc.description.abstract Electronic coupling Vda is one of the key parameters that determine the rate of charge transfer through DNA. While there have been several computational studies of Vda for hole transfer, estimates of electronic couplings for excess electron transfer (ET) in DNA remain unavailable. In the paper, an efficient strategy is established for calculating the ET matrix elements between base pairs in a π stack. Two approaches are considered. First, we employ the diabatic-state (DS) method in which donor and acceptor are represented with radical anions of the canonical base pairs adenine-thymine (AT) and guanine-cytosine (GC). In this approach, similar values of Vda are obtained with the standard 6-31 G* and extended 6-31++ G* basis sets. Second, the electronic couplings are derived from lowest unoccupied molecular orbitals (LUMOs) of neutral systems by using the generalized Mulliken-Hush or fragment charge methods. Because the radical-anion states of AT and GC are well reproduced by LUMOs of the neutral base pairs calculated without diffuse functions, the estimated values of Vda are in good agreement with the couplings obtained for radical-anion states using the DS method. However, when the calculation of a neutral stack is carried out with diffuse functions, LUMOs of the system exhibit the dipole-bound character and cannot be used for estimating electronic couplings. Our calculations suggest that the ET matrix elements Vda for models containing intrastrand thymine and cytosine bases are essentially larger than the couplings in complexes with interstrand pyrimidine bases. The matrix elements for excess electron transfer are found to be considerably smaller than the corresponding values for hole transfer and to be very responsive to structural changes in a DNA stack
dc.format.mimetype application/pdf
dc.language.iso eng
dc.publisher American Institute of Physics
dc.relation.isformatof Reproducció digital del document publicat a: http://dx.doi.org/10.1063/1.1961400
dc.relation.ispartof © Journal of Chemical Physics, 2005, vol. 123, núm. 3, p. 1-5
dc.relation.ispartofseries Articles publicats (D-Q)
dc.rights Tots els drets reservats
dc.subject ADN
dc.subject Dinàmica molecular
dc.subject Electrònica molecular
dc.subject Electrons
dc.subject Orbitals moleculars
dc.subject Transferència de càrrega
dc.subject Charge transfer
dc.subject DNA
dc.subject Molecular dynamics
dc.subject Molecular electronics
dc.subject Molecular orbitals
dc.title Estimates of electronic coupling for excess electron transfer in DNA
dc.type info:eu-repo/semantics/article
dc.identifier.doi http://dx.doi.org/10.1063/1.1961400


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