2004/05/13 by A. Omerzu, M. Licer, Matjaž Ličer +4 · 1 citation
Engineering · Physics and Astronomy · #Advanced Chemical Physics Studies #Molecular Junctions and Nanostructures #Spectroscopy and Quantum Chemical Studies #cond-mat.soft
paper · pdf · doi:10.1103/physrevlett.93.218101
published as Phys. Rev. Lett. 93, 218101 (2004)
arxiv created 2004/05/13 · openalex publication_date 2004/11/15 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
We report on a study of the interactions between holes and molecular vibrations on dry DNA using photoinduced infrared absorption spectroscopy. Laser photoexcited holes are found to have a room-temperature lifetime in excess of tau > 1 ms, clearly indicating the presence of localization. However, from a quantitative model analysis of the frequency shifts of vibrational modes caused by the holes, we find the hole-vibrational coupling constant to be relatively small, lambda approximately 0.2. This interaction leads to a change in the conformational energy of DeltaE0 approximately 0.015 eV, which is too small to cause self-trapping at room temperature. We conclude that, at least in the dry (A) form, DNA is best understood in terms of a double chain of coupled quantum dots arising from the pseudorandom chain sequence of base pairs, in which Anderson localization prevents the formation of a metallic state.