RT Journal Article T1 Analysis of the interband optical transitions: Characterization of synthetic DNA band structure A1 Díaz García, Elena AB We analyze the band structure and interband optical transitions in a dangling backbone ladder DNA model. Using this model, semiconducting synthetic poly(G)- poly(C) DNA is studied by means of a tight-binding model traditionally used for transport studies. Numerical calculations for optical absorption spectra are also presented. By studying the eigenstates' symmetries in uniform and nonuniform DNA chains, we conclude that, in both cases, the transitions are almost vertical in K space. The optical gap turns out larger than the electronic one, and an indirect band gap electronic structure for this DNA model is revealed. The effects of the environment, which are relevant for the wet form of DNA, are taken into account by introducing disorder in the backbone levels. We demonstrate that they affect more the spectra in the case of parallel polarization of the incoming light (with respect to the molecule axis). In such a case, the closure of the gap appears for a large enough disorder. We also consider the natural helix DNA conformation and find unusual selection rules for interband optical transitions. We propose that a comparison between the obtained spectra and the experiments can provide an insight into the electronic band structure of DNA. PB American Institute of Physics SN 0021-9606 YR 2008 FD 2008-05-07 LK https://hdl.handle.net/20.500.14352/52044 UL https://hdl.handle.net/20.500.14352/52044 LA eng NO (c) 2008 American Institute of Physics.The author thanks F. Domínguez-Adame, E. Maciá, and A. Rodríguez for helpful discussions. This work was supported by MEC Project No. MOSAICO and BSCH-UCM Project No. PR34/07-15916. NO Ministerio de Educación y Ciencia (MEC) NO BSCH-UCM DS Docta Complutense RD 10 abr 2025