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Nonadiabatic Dynamics of Uracil: Population Split among Different Decay Mechanisms
- 1.0364303 - ÚOCHB 2012 RIV US eng J - Journal Article
Nachtigallová, Dana - Aquino, A. J. A. - Szymczak, J. J. - Barbatti, M. - Hobza, Pavel - Lischka, H.
Nonadiabatic Dynamics of Uracil: Population Split among Different Decay Mechanisms.
Journal of Physical Chemistry A. Roč. 115, č. 21 (2011), s. 5247-5255. ISSN 1089-5639. E-ISSN 1520-5215
R&D Projects: GA MŠMT LC512
Institutional research plan: CEZ:AV0Z40550506
Keywords : ab initio calculations * excited states * nucleic acids * photodynamics
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 2.946, year: 2011
Nonadiabatic dynamics simulations performed at the state-averaged CASSCF method are reported for uracil. The dominant mechanism is characterized by relaxation into the S(2) minimum of .pi.pi.* character followed by the relaxation to the S(1) minimum of n.pi. * character. This mechanism contributes to the slower relaxation with a decay constant larger than 1.5 ps, in good agreement with the long time constants experimentally observed. A minor fraction of trajectories decay to the ground state with a time constant of about 0.7 ps, which should be compared to the experimentally observed short constant. A contribution of the relaxation proceeding via a ring-opening conical intersection was also observed. The existence of these two latter channels together with a reduced long time constant is responsible for a significantly shorter lifetime of uracil compared to that of thymine.
Permanent Link: http://hdl.handle.net/11104/0006547
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