Specific Ion Effects at the Air/Water Interface

Nanofluidic transport governed by the liquid/vapour interface

“…This study carefully minimized temperature gradients by tracing the condensation of H 2 17 O on water droplets injected into vapour at high speeds, although at temperatures below 7 °C and at speeds corresponding to a vapour temperature elevated by ~10-50 K. Interestingly, the condensation coefficients match with those in the present work if the temperature scale is shifted by ~40 K. The experiments reported here overcome many of the major uncertainties involved in measurement of the condensation coefficient, and demonstrate that majority of water molecules incident on the liquid-vapour interface are reflected back into the vapour phase. Although the condensation coefficient measured here is strictly speaking an averaged value of that at the two interfaces, the absence of significant dependence on salt concentration, or the type of anion (Cl -was switched with I -that tends to accumulate at the interface 50 as described in Supplementary Section 11)…”

Interfacial Structures of Acidic and Basic Aqueous Solutions

“…1,2 They have been the topics of extensive theoretical and experimental studies in recent years, [3][4][5][6][7][8] but good understanding of the water interfacial structure at the molecular level is still lacking. The most concerned question is whether H + and OH -ions would emerge at the interface and affect the interfacial hydrogen-bonding network of water.…”

“…Molecular dynamics (MD) simulations predicted that protons (H + ) could appear at the interface in the form of hydronium(H 3 O + ), but OH -should be repelled from the water surface. 3,[9][10][11][12] The details, such as the depth profile of ion concentrations, depend very much on the molecular model and interaction potentials assumed. [9][10][11][12] Experiments carried out with scanning tunneling microscopy (STM) 13 , X-ray spectroscopy 14,15 , and attenuated total reflection (ATR) 8 have been used to verify the theoretical prediction.…”

Microscopic structure and dynamics of air/water interface by computer simulations—comparison with sum-frequency generation experiments

“…Therefore, using eqn (2), we use the above e's to obtain A eff 's from the calculated A ijk 's. The A ijk 's in eqn (2) are the resonant components of macroscopic susceptibility tensor, and can be represented at a molecular level as an ensemble average of the molecular hyperpolarizability in the body fixed frame, b q,lmn (corresponding to the hyperpolarizability A q of Du et al 9 ), of the interfacial water molecules in the lab frame (denoted by ijk), where q corresponds to the IR resonant mode of the free OH bond. The derivation begins with the Fourier-Laplace transform of the classical SFG response function: related references are 26,29,[33][34][35][36] where a ij is the instantaneous polarizability tensor of the entire surface, and m k is the instantaneous dipole moment vector of the surface.…”

“…The hydrogen (H) bonded structure of water at the air/water interface [1][2][3][4][5] is of fundamental interest because it determines the properties of aqueous interfaces and their reactivity. Certain atmospheric reactions, 6 such as those involved in ozone depletion, are known to be catalyzed by the ice surface on cloud particles.…”