Change of the isoelectric point of hemoglobin at the air/water interface probed by the orientational flip-flop of water molecules

2017 ◽  
Vol 19 (16) ◽  
pp. 10292-10300 ◽  
Author(s):  
Stéphanie Devineau ◽  
Ken-ichi Inoue ◽  
Ryoji Kusaka ◽  
Shu-hei Urashima ◽  
Satoshi Nihonyanagi ◽  
...  
Keyword(s):  
Vibrational Spectroscopy ◽  
Isoelectric Point ◽  
Water Molecules ◽  
Water Interface ◽  
Flip Flop ◽  
Air Water Interface

Nonlinear vibrational spectroscopy reveals that the isoelectric point of proteins can largely change when the proteins are adsorbed at the air/water interface.

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>

scholarly journals Orientation and Motion of Water Molecules at Air/Water Interface

2006 ◽  
Vol 19 (1) ◽  
pp. 20-24 ◽  
Author(s):  
Wei Gan ◽  
Dan Wu ◽  
Zhen Zhang ◽  
Yuan Guo ◽  
Hong-fei Wang
Keyword(s):  
Water Molecules ◽  
Water Interface ◽  
Air Water Interface

Polarization-Modulated FT-IR Spectroscopy of a Spread Monolayer at the Air/Water Interface

1993 ◽  
Vol 47 (7) ◽  
pp. 869-874 ◽  
Author(s):  
D. Blaudez ◽  
T. Buffeteau ◽  
J. C. Cornut ◽  
B. Desbat ◽  
N. Escafre ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Liquid Water ◽  
Arachidic Acid ◽  
Water Molecules ◽  
Water Interface ◽  
Vibrational Modes ◽  
Experimental Conditions ◽  
Air Water Interface ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

This study devoted to the FT-IR spectroscopy of monolayers spread at the air/water interface is, to our knowledge, the first report presenting complete mid-infrared monolayer spectra perfectly extracted from the strong water vapor bands. This has been possible with the use of the polarization-modulated IRRAS method, which is not sensitive to the isotropic absorptions of the sample environment. On the basis of theoretical modeling and experiments, the best angle of incidence has been found near 76° for detection of intraplane as well as out-of-plane oriented monolayer absorptions. With the use of such experimental conditions, on the normalized difference (covered vs. uncovered water) PM-IRRAS spectra, monolayer vibrational bands come out upward or downward, depending on the orientation of their transition moment with respect to the interface. Application to the study of deuterated arachidic acid and arachidate monolayers allows observation of the vibrational modes of the polar head groups interacting with the liquid water molecules and provides some evidence of their symmetrical anchoring. The vibrational modes of the liquid water subphase contribute to these difference spectra as broad dips that certainly contain information on a possible restructuring of the water molecules at the interface.

Molecular interactions of organic molecules at the air/water interface investigated by sum frequency generation vibrational spectroscopy

2017 ◽  
Vol 19 (6) ◽  
pp. 4488-4493 ◽  
Author(s):  
Wenting Wang ◽  
Shuji Ye
Keyword(s):  
Vibrational Spectroscopy ◽  
Molecular Interactions ◽  
Organic Molecules ◽  
Sum Frequency Generation ◽  
Second Order ◽  
Water Interface ◽  
Sum Frequency ◽  
Air Water Interface ◽  
Frequency Generation

Second-order Fermi resonanance interaction provides an effective vibrational optical ruler for characterizing the molecular interactions at interfaces.

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