TY - JOUR
T1 - New insights into the state trapping of UV-excited thymine
AU - Stojanović, Ljiljana
AU - Bai, Shuming
AU - Nagesh, Jayashree
AU - Izmaylov, Artur F.
AU - Crespo-Otero, Rachel
AU - Lischka, Hans
AU - Barbatti, Mario
N1 - Funding Information:
Ljiljana Stojanović, Shuming Bai, and Mario Barbatti thank the support of the Aix-Marseille Initiative d'Excellence (A∗MIDEX) grant (No. ANR-11-IDEX-0001-02) funded by the French Government "Investissements d'Avenir" program supervised by the Agence Nationale de la Recherche. This work was granted access to the HPC resources of Aix-Marseille Université financed by the project Equip@Meso (ANR-10-EQPX-29-01) also within the "Investissements d'Avenir" program. Artur F. Izmaylov acknowledges funding from a Sloan Research Fellowship and the Natural Sciences and Engineering Research Council of Canada (NSERC) through the Discovery Grants Program.
Publisher Copyright:
© 2016 by the authors; licensee MDPI.
PY - 2016/11/1
Y1 - 2016/11/1
N2 - After UV excitation, gas phase thymine returns to a ground state in 5 to 7 ps, showing multiple time constants. There is no consensus on the assignment of these processes, with a dispute between models claiming that thymine is trapped either in the first (S1) or in the second (S2) excited states. In the present study, a nonadiabatic dynamics simulation of thymine is performed on the basis of ADC(2) surfaces, to understand the role of dynamic electron correlation on the deactivation pathways. The results show that trapping in S2 is strongly reduced in comparison to previous simulations considering only non-dynamic electron correlation on CASSCF surfaces. The reason for the difference is traced back to the energetic cost for formation of a CO π bond in S2.
AB - After UV excitation, gas phase thymine returns to a ground state in 5 to 7 ps, showing multiple time constants. There is no consensus on the assignment of these processes, with a dispute between models claiming that thymine is trapped either in the first (S1) or in the second (S2) excited states. In the present study, a nonadiabatic dynamics simulation of thymine is performed on the basis of ADC(2) surfaces, to understand the role of dynamic electron correlation on the deactivation pathways. The results show that trapping in S2 is strongly reduced in comparison to previous simulations considering only non-dynamic electron correlation on CASSCF surfaces. The reason for the difference is traced back to the energetic cost for formation of a CO π bond in S2.
KW - Computational theoretical chemistry
KW - Nonadiabatic dynamics
KW - Nucleobases
KW - Photochemistry
KW - Surface hopping
KW - Thymine
KW - Ultrafast processes
UR - http://www.scopus.com/inward/record.url?scp=84997611134&partnerID=8YFLogxK
U2 - 10.3390/molecules21111603
DO - 10.3390/molecules21111603
M3 - Article
C2 - 27886099
AN - SCOPUS:84997611134
SN - 1420-3049
VL - 21
JO - Molecules
JF - Molecules
IS - 11
M1 - 1603
ER -