Heterodyne-Detected Sum Frequency Generation Spectroscopic Study of Weakly Hydrogen-Bonded Water at Charged Lipid Interfaces, Revisited
Yuki Nojima, S. Yamaguchi
Abstract
The presence/absence of weakly hydrogen-bonded water molecules buried in the hydrophobic moiety of charged lipids at aqueous interfaces has been a matter of debate. We concluded their presence in our previous study, which was later questioned from the viewpoint of the so-called χ(3) effect. Here we show that heterodyne-detected sum frequency generation (HD-SFG) spectra of the same lipid interfaces with excess salt in the aqueous subphase allow us to reconfirm the presence of the weakly hydrogen-bonded water in the hydrophobic moiety after successfully subtracting the χ(3) contribution from the observable.
Topics & Concepts
MoietyAqueous solutionSum frequency generation spectroscopyObservableHydrogenSum-frequency generationMoleculeChemistryHeterodyne (poetry)Spectral lineHydrogen bondChemical physicsAnalytical Chemistry (journal)Organic chemistryOpticsPhysicsNonlinear opticsQuantum mechanicsAcousticsLaserSpectroscopy and Quantum Chemical StudiesMolecular spectroscopy and chiralityPhotoreceptor and optogenetics research