Stark effect or coverage dependence? Disentangling the EC-SEIRAS vibrational shift of sulfate on Au(111)

Jonas H.K. Pfisterer, Ulmas E. Zhumaev, William Cheuquepan, Juan M. Feliu, Katrin F. Domke

Research output: Contribution to journalArticlepeer-review

Abstract

Infrared spectroscopy is a widely employed analytical tool in (electrochemical) surface science as the spectra contain a wealth of information about the interaction of interfacial adsorbates with their environment. Separating and quantifying individual contributions, for example, of co-adsorbates, the substrate or electric field effects, on the overall spectral response, however, is often non-trivial as the various interactions manifest themselves in similar spectral behavior. Here, we present an experimental approach to differentiate between and quantify potential-induced coverage dependence and field-related Stark effects observed in a sulfate band shift of 93.5 ± 1.5 cm-1/V in electrochemical infrared spectra of the showcase sulfate/Au(111) interface. In combination with a simple linear model equation used to describe the potential-induced peak shift of the sulfate stretch vibration, we determine the coverage dependence contribution to be 15.6 ± 1.2 cm-1SO and the Stark effect to amount to 75.6 ± 2.7 cm-1/V. Our work provides a novel route to gain fundamental insight into interfacial adsorbate interactions in electrochemical surface science.

Original languageEnglish
Article number5047941
Pages (from-to)041709
JournalJournal of Chemical Physics
Volume150
Issue number4
DOIs
Publication statusPublished - 28 Jan 2019
Externally publishedYes

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