Considering 41 electronic transitions in small-and medium-sized organic molecules, we benchmark the performances of 36 hybrid functionals within time-dependent density-functional theory (TD-DFT) and nine wave function theory (WFT) methods [CCSDT, CC3, CCSDT-3, CCSDR(3), CCSD, CC2, ADC(3), ADC(2), and SOS-ADC(2)]. Compared to highly accurate experimental 0−0 energies, it turns out that all coupled cluster (CC) approaches that include contributions from the triples [i.e., CCSDT, CC3, CCSDT-3 and CCSDR(3)] deliver a root-mean-square error (RMSE) smaller than or equal to 0.05 eV. The remaining WFT methods [i.e., CCSD, CC2, ADC(3), ADC(2), and SOS-ADC(2)] yield larger deviations with RMSE lying between 0.11 and 0.27 eV. Irrespective of the exchange−correlation functional, TD-DFT yields larger deviations (RMSE ⩾ 0.30 eV). For vertical transitions without clear experimental equivalents (such as vertical absorption and fluorescence), a comparison between TD-DFT and CC3 provides a globally unchanged ranking of the various functionals. However, the errors on emission energies tend to be larger than on absorption energies, hinting that studying the latter property is not sufficient to gain a complete view of TD-DFT's performances. Finally, by cross-comparisons between TD-DFT and WFT, we observe that the WFT method selected as reference significantly impacts the conclusions regarding the overall accuracy of a given exchange−correlation functional. For example, for vertical absorption energies, the "best" functional is TPSSh (RMSE = 0.29 eV) based on CC3 reference energies, while LC-ωPBE (RMSE = 0.12 eV) is superior to the other functionals when one considers ADC(3) as the reference method.

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Carbon dots (C-dots) possess the attractive properties of high stability, low toxicity, good water solubility, simple synthetic routes as well as size and excitation-dependent photoluminescence (PL).The aim of this work was to synthesize photoluminescent C-dots by hydrothermal method using acerola fruit (Malpighiaemarginata) as a row material, since this fruit contains large number of organic molecules. Studies about the optimal synthesis conditions were performed, where these organic molecules were converted into C-dots by hydrothermal carbonization at 180 ºC for 18 h. The C-dots exhibited a green emission light at 459 nm when excited under UV-light ( λ ex = 370 nm). These nanomaterials were also successfully used to prepare C-dots/poly (vinyl alcohol) luminescent composites (C-dots/PVA). Both C-dots and C-dots/PVA composite films were investigated by using colorimetric visual sensor for Fe 3+ metal ions detection. The results show that the prepared C-dots and C-dots/poly presented strong green emission light. The emission spectra of above materials were quenched in the presence of Fe 3+ ions. Thus, highly specific "turn off" fluorescence sensing of Fe 3+ was achieved using fluorescent C-dots. Regarding, this work describe that the polymeric films as sensors of metallic ions in aqueous solution appears as a new perspectives to design new composite materials.

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