The excited states of pi-stacked 9-methyl adenine oligomers: a TD-DFT study in aqueous solution
Articolo
Data di Pubblicazione:
2008
Abstract:
An extensive PCM/TD-DFT study of the excited states of p-stacked 9-methyladenine oligomers
(from the dimer up to the pentamer), adopting the B-DNA conformation, is reported. Linear
response PCM/TD-PBE0 calculations provide a reliable description of the stacking effect on the
bright excited states but PBE0, when compared to CAM-B3LYP, LC-oPBE and M052X
functionals, overestimates the stability of the electronic states with inter-monomer charge transfer
(CT) character. On the other hand, state specific PCM/TD-DFT calculations confirm that the
lowest energy excited state of the dimer corresponds to a dark excimer produced by intermonomer
CT between two stacked bases. Confirming the experimental indications, the
spectroscopic states of the oligomers are delocalized over multiple bases.
(from the dimer up to the pentamer), adopting the B-DNA conformation, is reported. Linear
response PCM/TD-PBE0 calculations provide a reliable description of the stacking effect on the
bright excited states but PBE0, when compared to CAM-B3LYP, LC-oPBE and M052X
functionals, overestimates the stability of the electronic states with inter-monomer charge transfer
(CT) character. On the other hand, state specific PCM/TD-DFT calculations confirm that the
lowest energy excited state of the dimer corresponds to a dark excimer produced by intermonomer
CT between two stacked bases. Confirming the experimental indications, the
spectroscopic states of the oligomers are delocalized over multiple bases.
Tipologia CRIS:
01.01 Articolo in rivista
Elenco autori:
Improta, Roberto
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