Exploring concerted effects of base pairing and stacking on the excited-state nature of DNA oligonucleotides by DFT and TD-DFT studies
2011 (English)In: International Journal of Quantum Chemistry, ISSN 0020-7608, E-ISSN 1097-461X, Vol. 111, no 10, 2366-2377 p.Article in journal (Refereed) Published
We have taken (dA)5, (dT)5, and (dA)5•(dT)5 as model systems to study concerted effects of base pairing and stacking on excited-state nature of DNA oligonucleotides using density functional theory (DFT) and time dependent DFTmethods. The spectroscopic states are determined to be of a partial A →A charge transfernature in the A•T oligonucleotides. The T → T charge-transfer transitionsproduce dark states, which are hidden in the energy region of the steady-stateabsorption spectra. This is different from the previous assignment that the T → Tcharge-transfer transition is responsible for a shoulder at the red side of the first strongabsorption band. The A →T charge-transfer states were predicted to have relativelyhigh energies in the A•T oligonucleotides. The present calculations predict that the T→A charge-transfer states are not involved in the spectra and excited-state dynamics ofthe A•T oligonucleotides. In addition, the influence of base pairing and stacking on thenature of the 1nΠ* and 1ΠΠ* states are discussed in detail.
Place, publisher, year, edition, pages
2011. Vol. 111, no 10, 2366-2377 p.
DNA oligonucleotides, DFT, excited states
IdentifiersURN: urn:nbn:se:kth:diva-33578DOI: 10.1002/qua.22524ISI: 000289994300023ScopusID: 2-s2.0-79955381712OAI: oai:DiVA.org:kth-33578DiVA: diva2:416166
QC 201105202011-05-102011-05-102011-05-30Bibliographically approved