Exciton Trapping Dynamics in DNA Multimers

Rocio Borrego-Varillas (1) , Giulio Cerullo (1) , Dimitra Markovitsi (2, 3)

1 POLIMI - Dipartimento di Fisica [Politecnico Milano]
2 LIDyl - Laboratoire Interactions, Dynamiques et Lasers (ex SPAM)
3 DICO - Dynamique et Interactions en phase Condensée

Using as a model the single adenine strand (dA)20, we study the ultrafast evolution of electronic excitations in DNA with a time resolution of 30 fs. Our transient absorption spectra in the UV and visible spectral domains show that internal conversion among photogenerated exciton states occurs within 100 fs. Subsequently, the ππ* states acquire progressively charge-transfer character before being completely trapped, within 3 ps, by fully developed charge-transfer states corresponding to transfer of an electron from one adenine moiety to another (A+A–).

Domains: Theoretical and/or physical chemistry; Chemical Physics [physics.chem-ph]

Rocio Borrego-Varillas, Giulio Cerullo, Dimitra Markovitsi. Exciton Trapping Dynamics in DNA Multimers. Journal of Physical Chemistry Letters, 2019, 10 (7), pp.1639-1643. ⟨10.1021/acs.jpclett.9b00450⟩. ⟨cea-02096303⟩