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Vibrational Stark Effects: Ionic Influence on Local Fields

[Image: see text] Molecules containing vibrational Stark shift reporters provide a useful tool for measuring DC electric fields in situ. To quantify this effect theoretically, density functional theory (DFT) calculations are usually utilized in a uniform electric field. However, using a combined the...

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Detalles Bibliográficos
Autores principales: Wright, Demelza, Sangtarash, Sara, Mueller, Niclas S., Lin, Qianqi, Sadeghi, Hatef, Baumberg, Jeremy J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2022
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9189927/
https://www.ncbi.nlm.nih.gov/pubmed/35623089
http://dx.doi.org/10.1021/acs.jpclett.2c01048
Descripción
Sumario:[Image: see text] Molecules containing vibrational Stark shift reporters provide a useful tool for measuring DC electric fields in situ. To quantify this effect theoretically, density functional theory (DFT) calculations are usually utilized in a uniform electric field. However, using a combined theoretical and experimental study, we demonstrate here that uniform field DFT cannot simultaneously model the behavior of the three strongest vibrational modes in molecules forming a monolayer on an electrode. We show, by directly modeling ionic movement, that the measured Stark shifts are explained by partial electrical double-layer penetration into the molecular layer. This effect is sensitive to the local environment, and the Stark shifts can be fully suppressed experimentally by introducing a mixed molecular layer that prevents ionic double-layer penetration.