Vibrational Coupling and Hydrogen Bonding at the Air∕Water Interface

2010 ◽  
Author(s):  
Igor V. Stiopkin ◽  
Champika Weeraman ◽  
Alexander V. Benderskii ◽  
P. M. Champion ◽  
L. D. Ziegler
Keyword(s):  
Hydrogen Bonding ◽  
Water Interface ◽  
Vibrational Coupling ◽  
Air Water Interface

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>

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>

scholarly journals Probing Interfacial Effects on Ionization Energies: The Surprising Banality of Anion-Water Hydrogen Bonding at the Air/Water Interface

2021 ◽  
Author(s):  
Suranjan Paul ◽  
John Herbert
Keyword(s):  
Hydrogen Bonding ◽  
Photoelectron Spectroscopy ◽  
Solvation Shell ◽  
Bulk Liquid ◽  
Water Interface ◽  
Simulation Data ◽  
Ionization Energies ◽  
Air Water Interface ◽  
Dynamics Simulations ◽  
Water Hydrogen

Liquid microjet photoelectron spectroscopy is an increasingly common technique to measure vertical ionization energies (VIEs) of aqueous solutes, although the interpretation of these experiments is subject to questions regarding sensitivity to bulk versus interfacial solvation environments. Here, we compute aqueous-phase VIEs for a set of inorganic anions, some of which partition preferentially at the air/water interface, using a combination of molecular dynamics simulations and electronic structure calculations. The results are in excellent agreement with experiment, regardless of whether the simulation data are restricted to ions at the air/water interface or to those in bulk liquid water. Although the computed VIEs are sensitive to ion-water hydrogen bonding, we find that the short-range solvation structure is sufficiently similar in the bulk and interfacial environments that it proves impossible to discriminate between the two on the basis of the VIE, a conclusion that has important implications for the interpretation of liquid-phase photoelectron spectroscopy. More generally, analysis of the simulation data suggests that partitioning of soft anions at the air/water interface is largely a second (or third) solvation shell effect, arising from disruption of water-water hydrogen bonds and not from significant changes in first-shell anion-water hydrogen bonding. <br>

Structure at the air/water interface in the presence of phenol: a study using heterodyne-detected vibrational sum frequency generation and molecular dynamics simulation

2018 ◽  
Vol 20 (5) ◽  
pp. 3002-3009 ◽  
Author(s):  
Ryoji Kusaka ◽  
Tatsuya Ishiyama ◽  
Satoshi Nihonyanagi ◽  
Akihiro Morita ◽  
Tahei Tahara
Keyword(s):  
Molecular Dynamics ◽  
Hydrogen Bonding ◽  
Molecular Dynamics Simulation ◽  
Organic Molecule ◽  
Sum Frequency Generation ◽  
Dynamics Simulation ◽  
Water Interface ◽  
Sum Frequency ◽  
Bonding Structure ◽  
Air Water Interface

A simple, neutral organic molecule, phenol, forms a specific hydrogen-bonding structure with water at the air/water interface.

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