scholarly journals Excited states and energy transfer among DNA bases in double helices

2007 ◽  
Vol 6 (7) ◽  
pp. 717 ◽  
Author(s):  
Dimitra Markovitsi ◽  
Thomas Gustavsson ◽  
Francis Talbot
Keyword(s):  
Energy Transfer ◽  
Excited States ◽  
Dna Bases ◽  
Double Helices

Interaction of UV radiation with DNA helices

2009 ◽  
Vol 81 (9) ◽  
pp. 1635-1644 ◽  
Author(s):  
Dimitra Markovitsi
Keyword(s):  
Energy Transfer ◽  
Excited States ◽  
Flash Photolysis ◽  
Photon Absorption ◽  
Base Pairs ◽  
Relaxation Energy ◽  
Double Helices ◽  
Fluorescence Upconversion ◽  
Theoretical Investigations ◽  
Franck Condon

Recent experimental and theoretical investigations dealing with model DNA double helices, composed of either adenine–thymine (A–T) or guanine–cytosine (G–C) base pairs, and G quadruplexes shed some light on the excited states populated by photon absorption and their relaxation, energy transfer among bases, and one-photon ionization. These studies revealed that the Franck–Condon excited states of DNA helices cannot be considered as the sum of their monomeric constituents because electronic coupling induces delocalization of the excitation over a few bases. Energy transfer takes place via intraband scattering in less than 100 fs. The fluorescence lifetimes of DNA helices detected by fluorescence upconversion and corresponding mainly to ππ* transitions are longer than that of an equimolar mixture of nucleotides; the only exception was observed for alternating G–C polymers. Moreover, nanosecond flash photolysis experiments showed that organization of bases within single and double helices may lead to a lowering of their ionization potential. Finally, the first determination regarding the time-scale needed for the formation of T dimers, the (6–4) adducts, was determined for the single strand (dT)20.

Collective Behavior of Franck−Condon Excited States and Energy Transfer in DNA Double Helices

2005 ◽  
Vol 127 (49) ◽  
pp. 17130-17131 ◽  
Author(s):  
Dimitra Markovitsi ◽  
Delphine Onidas ◽  
Thomas Gustavsson ◽  
Francis Talbot ◽  
Elodie Lazzarotto
Keyword(s):  
Energy Transfer ◽  
Excited States ◽  
Collective Behavior ◽  
Double Helices ◽  
Franck Condon

Theoretical Studies of Collision-induced Energy Transfer in Electronically Excited States

1990 ◽  
Vol 94 (11) ◽  
pp. 1253-1262 ◽  
Author(s):  
M. H. Alexander ◽  
A. Berning ◽  
A. Degli Esposti ◽  
A. Joerg ◽  
A. Kliesch ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Excited States ◽  
Theoretical Studies ◽  
Electronically Excited States ◽  
Electronically Excited

scholarly journals Ultrabroadband two-dimensional electronic spectroscopy reveals energy flow pathways in LHCII across the visible spectrum

2019 ◽  
Vol 205 ◽  
pp. 09034
Author(s):  
Minjung Son ◽  
Alberta Pinnola ◽  
Roberto Bassi ◽  
Gabriela S. Schlau-Cohen
Keyword(s):  
Energy Transfer ◽  
Excited States ◽  
Energy Flow ◽  
Energy Levels ◽  
Electronic Spectroscopy ◽  
Visible Region ◽  
Visible Spectrum ◽  
Energy Relaxation ◽  
Two Dimensional ◽  
Flow Pathways

We utilise ultrabroadband two-dimensional electronic spectroscopy to map out pathways of energy flow in LHCII across the entire visible region. In addition to the well-established, low-lying chlorophyll Qy bands, our results reveal additional pathways of energy relaxation on the higher-lying excited states involving the S2 energy levels of carotenoids, including ultrafast carotenoid-to-chlorophyll energy transfer on 90-150 fs timescales.

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