TY - JOUR
T1 - On the population of triplet states of 2-seleno-thymine
AU - Valverde, Danillo
AU - Mai, Sebastian
AU - Sanches de Araújo, Adalberto Vasconcelos
AU - Canuto, Sylvio
AU - González, Leticia
AU - Borin, Antonio Carlos
N1 - Funding Information:
D. V. acknowledges financial support from the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), under grants 2017/02612-4 and 2019/04413-4. S. C. thanks CAPES for the BioMol project 23038.004630/2014-35 and the National Institute of Science and Technology Complex Fluids (INCT-FCx) with the CNPq grant 141260/2017-3 and FAPESP grant 2014/50983-3. A. C. B. and A. V. S. A. thank the CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) for research fellowships (project numbers 302318/2017-8 and 153104/2015-5, respectively). A. C. B. thanks FAPESP for the research grant 2018/19454-5. Computations were performed on resources provided by HPC through Superintendência de Tecnologia da Informação da Universidade de São Paulo. The authors acknowledge the National Laboratory for Scientific Computing (LNCC/MCTI, Brazil) for providing HPC resources of the SDumont supercomputer , which have contributed to the research results reported within this paper. S. M. and L. G. gratefully acknowledge the Vienna Scientific Cluster (VSC3) for allocation of computational resources and the University of Vienna for continuous support.
Funding Information:
D. V. acknowledges financial support from the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), under grants 2017/02612-4 and 2019/04413-4. S. C. thanks CAPES for the BioMol project 23038.004630/2014-35 and the National Institute of Science and Technology Complex Fluids (INCT-FCx) with the CNPq grant 141260/2017-3 and FAPESP grant 2014/ 50983-3. A. C. B. and A. V. S. A. thank the CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) for research fellowships (project numbers 302318/2017-8 and 153104/2015-5, respectively). A. C. B. thanks FAPESP for the research grant 2018/19454-5. Computations were performed on resources provided by HPC through Superintendência de Tecno-logia da Informação da Universidade de São Paulo. The authors acknowledge the National Laboratory for Scientific Computing (LNCC/MCTI, Brazil) for providing HPC resources of the SDumont supercomputer (http://sdumont.lncc.br), which have contributed to the research results reported within this paper. S. M. and L. G. gratefully acknowledge the Vienna Scientific Cluster (VSC3) for allocation of computational resources and the University of Vienna for continuous support.
Publisher Copyright:
© the Owner Societies 2021.
PY - 2021/3/7
Y1 - 2021/3/7
N2 - The population and depopulation mechanisms leading to the lowest-lying triplet states of 2-Se-Thymine were studied at the MS-CASPT2/cc-pVDZ level of theory. Several critical points on different potential energy hypersurfaces were optimized, including minima, conical intersections, and singlet-triplet crossings. The accessibility of all relevant regions on the potential energy hypersurfaces was investigated by means of minimum energy paths and linear interpolation in internal coordinates techniques. Our analysis indicates that, after the population of the bright S2state in the Franck-Condon region, the first photochemical event is a barrierless evolution towards one of its two minima. After that, three viable photophysical deactivation paths can take place. In one of them, the population in the S2state is transferred to the T2stateviaintersystem crossing and subsequently to the T1state by internal conversion. Alternatively, the S1state could be accessed by internal conversion through two distinct conical intersections with S2state followed by singlet-triplet crossing with the T2state. The absence of a second minimum on the T1state and a small energy barrier on pathway along the potential energy surface towards the ground state from the lowest triplet state are attributed as potential reasons to explain why the lifetime of the triplet state of 2-Se-Thymine might be reduced in comparison with its thio-analogue.
AB - The population and depopulation mechanisms leading to the lowest-lying triplet states of 2-Se-Thymine were studied at the MS-CASPT2/cc-pVDZ level of theory. Several critical points on different potential energy hypersurfaces were optimized, including minima, conical intersections, and singlet-triplet crossings. The accessibility of all relevant regions on the potential energy hypersurfaces was investigated by means of minimum energy paths and linear interpolation in internal coordinates techniques. Our analysis indicates that, after the population of the bright S2state in the Franck-Condon region, the first photochemical event is a barrierless evolution towards one of its two minima. After that, three viable photophysical deactivation paths can take place. In one of them, the population in the S2state is transferred to the T2stateviaintersystem crossing and subsequently to the T1state by internal conversion. Alternatively, the S1state could be accessed by internal conversion through two distinct conical intersections with S2state followed by singlet-triplet crossing with the T2state. The absence of a second minimum on the T1state and a small energy barrier on pathway along the potential energy surface towards the ground state from the lowest triplet state are attributed as potential reasons to explain why the lifetime of the triplet state of 2-Se-Thymine might be reduced in comparison with its thio-analogue.
UR - http://www.scopus.com/inward/record.url?scp=85102708624&partnerID=8YFLogxK
U2 - 10.1039/d1cp00041a
DO - 10.1039/d1cp00041a
M3 - Article
C2 - 33650609
AN - SCOPUS:85102708624
SN - 1463-9076
VL - 23
SP - 5447
EP - 5454
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
IS - 9
ER -