| Texto completo | |
| Autor(es): |
Chagas, Julio C. V.
;
dos Santos, Luan G. F.
;
Nieman, Reed
;
Aquino, Adelia J. A.
;
do Monte, Silmar A.
;
Plasser, Felix
;
Szalay, Peter G.
;
Lischka, Hans
;
Machado, Francisco B. C.
Número total de Autores: 9
|
| Tipo de documento: | Artigo Científico |
| Fonte: | Physical Chemistry Chemical Physics; v. 27, n. 15, p. 13-pg., 2025-04-01. |
| Resumo | |
In this work, the electronic spectra of all-trans polyenes, from hexatriene to dodecahexaene are investigated. Special attention is given to the challenging description of the ionic 1(1)B(u)(+) state. A comprehensive wavefunction analysis of both singlet (2(1)A(g)(-), 1(1)B(u)(+), and 2(1)B(u)(-)) and triplet excited states (1(3)A(g)(-) and 1(3)B(u)(-)) is performed using a range of multireference correlated methods, including multireference configuration interaction with singles and doubles (MR-CISD) including a posteriori size-extensivity Pople correction (+P), and the multireference averaged quadratic coupled-cluster (MR-AQCC) method. While covalent states are well described by multi-configurational self-consistent field (MCSCF) theory, accurately describing the ionic state requires addressing size-extensivity errors, basis set effects, and, most importantly, sigma-pi electron correlation. Taking these factors into account, MR-CISD+P and MR-AQCC results mutually corroborate that the ionic 1(1)B(u)(+) state is the first vertically excited state in hexatriene and octatetraene. In decapentaene, extrapolated MR-CISD+P results indicate that the 2(1)A(g)(-) and 1(1)B(u)(+) states are nearly degenerate, while MR-AQCC suggests that the ionic state lies approximately 0.2 eV below the covalent state. From a wavefunction perspective, the ionic state is consistently well-represented by a single HOMO-LUMO excitation, whereas the contribution of doubly excited configurations increases with chain length for both covalent states. (AU) | |
| Processo FAPESP: | 22/16385-8 - Dispositivos orgânicos emissores de luz, conversores de energia via fissão singleto e materiais híbridos 0D/0D para produção de hidrogênio: abordagem da química computacional |
| Beneficiário: | Francisco Bolivar Correto Machado |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |