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http://hdl.handle.net/1843/50201| Type: | Artigo de Periódico |
| Title: | Observation of the sub-100 femtosecond population of a dark state in a thiobase mediating intersystem crossing |
| Authors: | Rocio Borrego Varillas Danielle Cristina Teles Ferreira Artur Nenov Irene Conti Lucia Ganzer Cristian Manzoni Marco Garavelli Ana Maria de Paula Giulio Cerullo |
| Abstract: | We combined sub-30 fs broadband transient absorption spectroscopy in the ultraviolet with state-of-the-art quantum mechanics/molecular mechanics simulations to study the ultrafast excited-state dynamics of the sulfur-substituted nucleobase 4-thiouracil. We observed a clear mismatch between the time scales for the decay of the stimulated emission from the bright ππ* state (76 ± 16 fs, experimentally elusive until now) and the buildup of the photoinduced absorption of the triplet state (225 ± 30 fs). These data provide evidence that the intersystem crossing occurs via a dark state, which is intermediately populated on the sub-100 fs time scale. Nonlinear spectroscopy simulations, extrapolated from a detailed CASPT2/MM decay path topology of the solvated system together with an excited state mixed quantum-classical nonadiabatic dynamics, reproduce the experimental results and explain the experimentally observed vibrational coherences. The theoretical analysis rationalizes the observed different triplet buildup times of 4- and 2-thiouracil. |
| Subject: | Absorção Níveis de energia Oscilações |
| language: | eng |
| metadata.dc.publisher.country: | Brasil |
| Publisher: | Universidade Federal de Minas Gerais |
| Publisher Initials: | UFMG |
| metadata.dc.publisher.department: | ICX - DEPARTAMENTO DE FÍSICA |
| Rights: | Acesso Restrito |
| metadata.dc.identifier.doi: | https://doi.org/10.1021/jacs.8b07057 |
| URI: | http://hdl.handle.net/1843/50201 |
| Issue Date: | 31-Oct-2018 |
| metadata.dc.url.externa: | https://pubs.acs.org/doi/10.1021/jacs.8b07057 |
| Appears in Collections: | Artigo de Periódico |
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