2026-06-01T11:52:04Zhttps://riuma.uma.es/rest/oai/request

oai:riuma.uma.es:10630/288412026-02-03T11:28:46Zcom_10630_2254col_10630_37953

Voltage tuning of photoinduced charge transfer resonances between 2,2′-bipyridine and a nanostructured silver electrode. Valdivia Mantas, Samuel Aranda, Daniel Otero-Fernández-de-Molina, Juan Carlos López-Tocón, Isabel Química física Efecto Raman de superficie intensificada Química de superficies Transferencia de carga Electrodos The effect of applied electric potentials and excitation wavelengths (785, 532, 473 nm) on the Surface-Enhanced Raman scattering (SERS) of 2,2′-bipyridine (2,2′-bpy) adsorbed on a silver electrode has been analyzed on the basis of a charge transfer (CT) resonance mechanism. DFT/TD-DFT calculations performed for a simple model of surface complex (Ag2-2,2′-bpy) point out that 2,2′-bpy preferably adsorbs through both nitrogen atoms in a cis-conformation with edge-on orientation. The calculated spectra in resonance with the two first bright metal-to-molecule charge transfer electronic states (CT0;B1 and CT1;B1) account for the main experimental features: the selective enhancement of the totally symmetric modes recorded at about 1585, 1560 and 1480 cm−1 under 532 nm line, staying the 1560 cm−1 band as the most intense under 473 nm line at more negative electrode potential. The split of SERS bands recorded in the 1600, 1000 and 600 cm−1 regions point to the existence of a monodentate coordination of the cis-conformer. The calculated resonance condition up to CT0 and CT1 states is fulfilled under 532 and 488 nm excitation lines, respectively, agreeing with the behaviour of the intensity-potential profile of the bands for each excitation wavelength. 2024-01-17T13:35:11Z 2024-01-17T13:35:11Z 2023-11-17 journal article Samuel Valdivia, Daniel Aranda, Juan Carlos Otero, Isabel López-Tocón, Voltage tuning of photoinduced charge transfer resonances between 2,2′-bipyridine and a nanostructured silver electrode, Applied Surface Science, Volume 646, 2024, 158871, ISSN 0169-4332, https://doi.org/10.1016/j.apsusc.2023.158871 https://hdl.handle.net/10630/28841 10.1016/j.apsusc.2023.158871 eng http://creativecommons.org/licenses/by-nc-nd/4.0/ open access Attribution-NonCommercial-NoDerivatives 4.0 Internacional