scholarly journals Disentangling Sum-Frequency Generation Spectra of the Water Bending Mode at Charged Aqueous Interfaces

2021 ◽  
Author(s):  
Takakazu Seki ◽  
Chun-Chieh Yu ◽  
Kuo-Yang Chiang ◽  
Junjun Tan ◽  
Shumei Sun ◽  
...  
Keyword(s):  
Sum Frequency Generation ◽  
Aqueous Interfaces ◽  
Sum Frequency ◽  
Bending Mode ◽  
Frequency Generation

scholarly journals Direct Evidence for a Surface and Bulk Specific Response in the Sum-Frequency Generation Spectrum of the Water Bend Vibration

2021 ◽  
Author(s):  
Carolyn Moll ◽  
Jan Versluis ◽  
Huib Bakker
Keyword(s):  
Pure Water ◽  
Frequency Component ◽  
Spectroscopic Studies ◽  
Quantitative Information ◽  
Sum Frequency Generation ◽  
Specific Response ◽  
Sum Frequency ◽  
Bending Mode ◽  
Frequency Generation ◽  
Aqueous Surfaces

Abstract Spectroscopic studies of aqueous surfaces can provide a fundamental understanding of interfacial processes. These studies have largely focused on the OH stretch vibrations of water, which is unfortunate as the bending mode is an attractive feature to probe as it is relatively free of inter- and intramolecular couplings. However, the origin of the response of the bending mode is highly debated and has been assigned to either surface-specific or to bulk effects. Here, we study the bending mode of pure water and charged aqueous surfaces using heterodyne-detected vibrational sum frequency generation spectroscopy (HD-VSFG) to quantify the two effects. Our results show a low - (1626 cm-1) and a high - (1656 cm-1) frequency component which can be unambiguously assigned to an interfacial dipole and a bulk quadrupolar response, respectively. We thus demonstrate that probing the bending mode provides structural and quantitative information on both the surface and the bulk.

Second Harmonic and Sum-Frequency Generation from Aqueous Interfaces Is Modulated by Interference

2016 ◽  
Vol 120 (17) ◽  
pp. 9165-9173 ◽  
Author(s):  
Grazia Gonella ◽  
Cornelis Lütgebaucks ◽  
Alex G. F. de Beer ◽  
Sylvie Roke
Keyword(s):  
Second Harmonic ◽  
Sum Frequency Generation ◽  
Aqueous Interfaces ◽  
Sum Frequency ◽  
Frequency Generation

Temperature Dependence of the Air/Water Interface Revealed by Polarization Sensitive Sum-Frequency Generation Spectroscopy

2018 ◽  
Author(s):  
Daniel R. Moberg ◽  
Shelby C. Straight ◽  
Francesco Paesani
Keyword(s):  
Temperature Dependence ◽  
Low Frequency ◽  
Potential Energy Function ◽  
Md Simulations ◽  
Sum Frequency Generation ◽  
Water Molecules ◽  
Water Interface ◽  
Sum Frequency ◽  
Air Water Interface ◽  
Frequency Generation

<div> <div> <div> <p>The temperature dependence of the vibrational sum-frequency generation (vSFG) spectra of the the air/water interface is investigated using many-body molecular dynamics (MB-MD) simulations performed with the MB-pol potential energy function. The total vSFG spectra calculated for different polarization combinations are then analyzed in terms of molecular auto-correlation and cross-correlation contributions. To provide molecular-level insights into interfacial hydrogen-bonding topologies, which give rise to specific spectroscopic features, the vSFG spectra are further investigated by separating contributions associated with water molecules donating 0, 1, or 2 hydrogen bonds to neighboring water molecules. This analysis suggests that the low frequency shoulder of the free OH peak which appears at ∼3600 cm−1 is primarily due to intermolecular couplings between both singly and doubly hydrogen-bonded molecules. </p> </div> </div> </div>

Bulk Contributions Modulate the Sum-Frequency Generation Spectra of Interfacial Water on Model Sea-Spray Aerosols

2018 ◽  
Author(s):  
Sandeep K. Reddy ◽  
Raphael Thiraux ◽  
Bethany A. Wellen Rudd ◽  
Lu Lin ◽  
Tehseen Adel ◽  
...  
Keyword(s):  
Single Layer ◽  
Sum Frequency Generation ◽  
Second Order ◽  
Interfacial Structure ◽  
Sea Spray ◽  
Third Order ◽  
Systematic Analysis ◽  
Sum Frequency ◽  
Structure Of Water ◽  
Frequency Generation

Vibrational sum-frequency generation (vSFG) spectroscopy is used to determine the molecular structure of water at the interface of palmitic acid monolayers. Both measured and calculated spectra display speci c features due to third-order contributions to the vSFG response which are associated with nite interfacial electric potentials. We demonstrate that theoretical modeling enables to separate the third-order contributions, thus allowing for a systematic analysis of the strictly surface-sensitive, second-order component of the vSFG response. This study provides fundamental, molecular-level insights into the interfacial structure of water in a neutral surfactant system with relevance to single layer bio-membranes and environmentally relevant sea-spray aerosols. These results emphasize the key role that computer simulations can play in interpreting vSFG spectra and revealing microscopic details of water at complex interfaces, which can be difficult to extract from experiments due to the mixing of second-order, surface-sensitive and third-order, bulk-dependent contributions to the vSFG response.

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