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.
The excited states of pi-stacked 9-methyl adenine oligomers: a TD-DFT study in aqueous solution
Improta R
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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
