Quantum-chemistry study of the ground and excited state absorption of distyrylbenzene : multi vs single reference methods
| Autor: | Oliveira, Eliezer Fernando de, 1988 |
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| Přispěvatelé: | UNIVERSIDADE ESTADUAL DE CAMPINAS |
| Rok vydání: | 2022 |
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| Zdroj: | Repositório da Produção Científica e Intelectual da Unicamp Universidade Estadual de Campinas (UNICAMP) instacron:UNICAMP |
| Popis: | Agradecimentos: The work in Madrid and Valencia was supported by the Spanish Ministerio de Economía y Competitividad (MINECO-FEDER Project No. CTQ2017-87054); the work in Madrid was further supported by the Severo Ochoa Program for Centers of Excellence in R&D of the MINECO (Grant No. SEV-2016-0686) and by the Campus of International Excellence (CEI) UAM+CSIC. D.R.-S. gratefully acknowledges the MICINN for a "Ramón y Cajal" grant (Reference No. RYC-2015-19234). Computational resources provided by the Centro de Cálculo Científico at Universidad Autónoma de Madrid (CCC-UAM) and by the Excited State Quantum Chemistry Group (QCEXVAL) cluster at Universitat de València are also acknowledged. The authors also thank Liangxuan Wang (Tübingen, Germany) and Javier Carmona-García (València, Spain) for helpful discussions Abstract: State-of-the-art complete active space self-consistent field/complete active space second order perturbation theory (CASPT2) calculations are used to investigate the role of double excitations on the ground state absorption (GSA) and excited state absorption (ESA) spectra of distyrylbenzene, an important prototype medium-sized pi-conjugated organic compound for optoelectronics. The multi-reference results are compared with linear and quadratic response time-dependent density functional theory (DFT) results, revealing an incomplete description of the electronic transitions in the latter. Careful selection of the active space and basis set in the CASPT2 approach allows for a reliable description of the GSA and ESA features; cost-effective DFT-based geometries can be utilized without a significant loss of accuracy. Double excitations are shown to play a pivotal role already for higher excited states in the GSA spectrum, however, without a relevant impact on the discernible spectral features. In the ESA, which shows a much more complex electronic situation, the crucial importance of double (and higher) excitations in all relevant electronic transitions, indeed, mandates a multiconfigurational treatment as done in the present benchmark study Fechado |
| Databáze: | OpenAIRE |
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