scholarly journals Polarization-Modulated Infrared Reflection Absorption Spectroscopic Studies of a Hydrogen-Bonding Network at the Air−Water Interface

1999 ◽  
Vol 103 (15) ◽  
pp. 2929-2934 ◽  
Author(s):  
Qun Huo ◽  
Leila Dziri ◽  
Bernard Desbat ◽  
K. C. Russell ◽  
Roger M. Leblanc
Keyword(s):  
Hydrogen Bonding ◽  
Spectroscopic Studies ◽  
Water Interface ◽  
Infrared Reflection ◽  
Air Water Interface ◽  
Hydrogen Bonding Network

Infrared Hide-and-Seek: Vibrational Excitons Conceal Surfactants at the Air/Water Interface

2020 ◽  
Author(s):  
Kimberly A. Carter-Fenk ◽  
Kevin Carter-Fenk ◽  
Michelle E Fiamingo ◽  
Heather Allen ◽  
John M. Herbert
Keyword(s):  
Arachidic Acid ◽  
Ionic Composition ◽  
Molecular Organization ◽  
Water Interface ◽  
Vibrational Coupling ◽  
One Dimensional ◽  
Infrared Reflection ◽  
Air Water Interface ◽  
Interface Science ◽  
Intermolecular Distances

<p>Surface-sensitive vibrational spectroscopy is a common tool for measuring molecular organization and intermolecular interactions at interfaces. Peak intensity ratios are typically used to extract molecular information from one-dimensional spectra but vibrational coupling between surfactant molecules can manifest as signal depletion in one-dimensional spectra. Through a combination of experiment and theory, we demonstrate the emergence of vibrational excitons in infrared reflection-absorption spectra of soluble and insoluble surfactants at the air/water interface. Vibrational coupling yields a signicant decrease in peak intensities corresponding to C-F vibrational modes of perfluorooctanoic acid molecules. Vibrational excitons also form between arachidic acid surfactants within a compressed monolayer, manifesting as signal reduction of C-H stretching modes. The aqueous phase ionic composition impacts surfactant intermolecular distances, thereby modulating vibrational coupling strength between surfactants. Our results serve as a cautionary tale against employing alkyl and fluoroalkyl vibrational peak intensities in analyses that are ubiquitous in interface science.</p>

Sign in / Sign up

Export Citation Format

Share Document