Influence of the Hydrogen-Bonding Environment on Vibrational Coupling in the Electrical Double Layer at the Silica/Aqueous Interface
- Shyam Parshotam
- Benjamin Rehl
- Franziska BusseFranziska BusseDepartment of Chemistry, University of Alberta, Edmonton, AlbertaT6G 2G2, CanadaMore by Franziska Busse
- Alex Brown
- , and
- Julianne M. Gibbs*
Vibrational spectroscopy is a powerful tool for determining the local hydrogen-bonding environment. However, vibrational coupling present in H2O makes it difficult to relate vibrational spectra to a molecular description of the system. While numerous bulk studies have shed light on this phenomenon, the influence of both intra- and intermolecular vibrational coupling on the resulting electrical double layer spectra at buried interfaces remains largely unexplored. By utilizing vibrational sum frequency generation (vSFG), electrokinetic measurements, and the maximum entropy method on isotopically diluted water (HOD) at the silica/aqueous interface, we reveal the influence of vibrational coupling on the Stern and diffuse layer spectra as the pH is varied. For the Stern layer spectra, we observe differences in the frequency centers at pH 2 that are less significant at higher pH, signifying the presence of intermolecular coupling that can be related to the double-donor hydrogen-bonded structure of water. Furthermore, the differences in the evolution of the Stern layer of H2O and HOD suggest that the presence of intramolecular coupling in the former may distort the spectral response. Moreover, we observe that the evolution of HOD closely matches the pKa of the out-of-plane silanols predicted by previous molecular dynamic simulations.
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This article is cited by 2 publications.
- Junjun Tan, Mengmeng Wang, Jiahui Zhang, Shuji Ye. Determination of the Thickness of Interfacial Water by Time-Resolved Sum-Frequency Generation Vibrational Spectroscopy. Langmuir 2023, 39
, 18573-18580. https://doi.org/10.1021/acs.langmuir.3c02906
- Shyam Parshotam, Wentong Zhang, Benjamin Rehl, Akemi Darlington, Md. Delwar H. Sikder, Alex Brown, Julianne M. Gibbs. Revealing Silica’s pH-Dependent Second Harmonic Generation Response with Overcharging. The Journal of Physical Chemistry C 2023, 127
, 8389-8398. https://doi.org/10.1021/acs.jpcc.3c02171