DOI | Trouver le DOI : https://doi.org/10.1021/jp054158nS1089-5639(05)04158-7 |
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Auteur | Rechercher : Zgierski, Marek1; Rechercher : Patchkovskii, Serguei1; Rechercher : Fujiwara, T.; Rechercher : Lim, E. |
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Affiliation | - Conseil national de recherches du Canada. Institut Steacie des sciences moléculaires du CNRC
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Format | Texte, Article |
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Résumé | The ultrafast radiationless decay of photoexcited uracil and cytosine has been investigated by ab initio quantum chemical methods based on CIS and CR-EOM-CCSD(T) electronic energy calculations at optimized CIS geometries. The calculated potential energy profiles indicate that the S1 S0 internal conversion of the pyrimidine bases occurs through a barrierless state switch from the initially excited 1* state to the out-of-plane deformed excited state of biradical character, which intersects the ground state at a lower energy. This three-state nonradiative decay mechanism predicts that replacement of the C5 hydrogen by fluorine introduces an energy barrier for the initial state switch, whereas replacement of the C6 hydrogen by fluorine does not. These predictions are borne out by the very different fluorescence yields of 5-fluorinated bases relative to the corresponding 6-fluorinated bases. It is concluded from these results that the origin of the ultrafast radiationless decay is the same for the two pyrimidine bases. |
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Date de publication | 2005-10-27 |
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Dans | |
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Langue | anglais |
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Publications évaluées par des pairs | Oui |
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Numéro NPARC | 12333589 |
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Exporter la notice | Exporter en format RIS |
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Signaler une correction | Signaler une correction (s'ouvre dans un nouvel onglet) |
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Identificateur de l’enregistrement | cfb4754c-39ff-4322-8288-7ad905f79c5d |
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Enregistrement créé | 2009-09-10 |
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Enregistrement modifié | 2020-04-07 |
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