Vibrational Stark Effects: Ionic Influence on Local Fields.
J Phys Chem Lett
; 13(22): 4905-4911, 2022 Jun 09.
Article
em En
| MEDLINE
| ID: mdl-35623089
ABSTRACT
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.
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MEDLINE
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En
Ano de publicação:
2022
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Article