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We systematically examined the effect of (H, Li)Cl and LiOH solvation on the O:H[sbnd]O bond network deformation, surface tension (contact angle), solution electrical conductivity, thermomics, and viscosity evolution aiming to clarifying the functionalities for ions, lone pairs, and protons acting in these solutions. Results confirmed that H + and electron lone pair ‘:’ introduction turns out the (H 3 O + , OH − )·4H 2 O motifs and that the Li + and Cl − form each a hydration volume through the screened electrostatic polarization. The (H 3 O + , OH − )·4H 2 O turns an O:H[sbnd]O bond into the H ↔ H anti–HB that disrupts the HCl solution network and its surface tension and into the O:⇔:O super–HB compressor that raises the LiOH solution surface tension and viscosity, as well as the solution temperature during solvation. The Li + /Cl − ion reserves/reduces its hydration volume because of the complete/incomplete screen shielding by the ordered hydrating H 2 O dipoles and the Cl − ↔ Cl − repulsion at higher concentrations. The invariant/variant Li + /Cl − hydration volume dictates, respectively, the linear/nonlinear concentration dependence of the Jones–Dole viscosity. Except for the HCl/H 2 O surface tension and LiOH/H 2 O viscosity, the conductivity, surface tension, and viscosity of these solutions follow the Jones–Dole notion that underscores the faction of bond transition from the mode of water to hydration. Accepted version

It has been a long pursuit to discriminate the ionic roles of mono- and di-valent salt solutions in modulating the hydrogen bonding network and solution properties. We attended this issue by examining the effect of concentrated YX 2 (Y[dbnd]Mg, Ca, Sr; X[dbnd]Cl, Br) solvation on O:H–O bonds transition from the mode of ordinary water to hydration in terms of the number fraction f YX2 (C) and the segmental O:H–O bond phonon stiffness shift Δω(C) with C being the solute concentration. The invariant df Y (C) / dC at C ≤

Understanding the performance of individual ions in salt solutions and the consequence of ionic hydration on hydrogen bonding network distortion, surface stress, and solution viscosity remains great challenge. We show herein findings pertained to alkali halide YX solutions using differential phonon spectroscopy (X = Cl, Br, I; Y = Li, Na, K, Rb, Cs): (i) an ion occupies eccentrically the tetrahedrally-coordinated interstitial of water to form a (±:4H2O:6H2O) hydration cell without bonding to H2O molecules; (ii) ionic polarization shortens and stiffens the H-O bond while does the O:H nonbond contrastingly; (iii) the screening of the hydrating water dipoles limits the cation hydration cell to be size invariant while the inter-anion repulsion reduces its hydration volume by weakening the anionic long-range electric field when the ionic separation shrinks; and (iv) the polarization of cation and anion dictates respectively the linear and the nonlinear part of Jones-Dale’s viscosity and surface stress. Findings would provide profound impact to the understanding and deep engineering of water, ice, and aqueous solutions.

Solvation of aldehydes and formic acids has an important impact to health care because these additives can damage DNA and denature proteins causing cancers with the mechanism behind remaining great challenge. From the perspective of solvent hydrogen bond (O:HO or HB with “:” being the electron lone pair of oxygen) transition from the mode of the ordinary water to the hydrating states, we examined the solvation bonding dynamics and the solute capabilities of O:HO bond and surface stress transition using differential Raman spectroscopy and contact angle detection. Results suggest that besides the short-range O:H van der Waals (vdW) bond, the H ↔ H and O: ⇔ :O repulsive intermolecular interactions, and the molecular dipolar polarization play important roles in disrupting the solution network and surface stress. Observations may infer the manner of DNA fragmentation by aldehyde and formic acid disruption. Accepted version

Freezing-thawing cycling of salt solutions is ubiquitously important to fields varying from biochemistry to agriculture, climate, and geological engineering. However, understanding the dynamics of energy exchange and freezing-temperature TN shift during phase transition of the concentrated solutions remains elusive despite intensive investigations since the discovery of Homeister series in 1888. Here we address this issue by focusing on the performance of the hydrogen bond (O:H O) in the fraction fS molecules of the hydrating supersolid phase and in the remaining fraction fO molecules of the pristine phase during NaCl solution ice formation. The supersolid formation is related to the effect of ionic polarization that shortens and stiffens the H O bond, while lengthening and weakening the O:H non-bonding interactions in the hydration cells. The supersolid phase is gel-like, less dense, viscoelastic, and mechanically and thermally stable. We demonstrate that the polarization-weakening of the O:H non-bonding interactions of the supersolid phase reduces the TN of the solution and that the H O cooling contraction in the quasisolid (QS) phase of the pristine water absorbs energy during the Liquid-QS-Ice transition of solution. At fS = 1, neither TN nor energy absorption is resolved within the range of 273 ± 20 K. The least saturation number of molecules is 10 per pair of Na+ and Cl− ions. These findings shall help to develop solutions with tunable TN for practical applications and to understand the mechanism of energy exchange during phase transition in the temperature and time domains.

Raman phonon differential spectrometrics (DPS) and contact angle measurements resolved that solvation of the NaX (X = HSO4, NO3, ClO4, SCN) complex salts stiffens the H O stretching phonon from 3200 to ~ 3500 cm− 1 and softens the O:H nonbond phonon from 180 to ~ 70 cm− 1 with rising of solution surface stress. The solute capability of bond transition in terms of the fraction coefficient, follows the relation, fNaX(C) ∝ 1-exp(− C/C0) towards saturation, with C being the solute concentration and C0 the decay constant. Observations evidence that: (i) the solute ionic field electrification aligns, stretches, and polarizes its neighboring H2O molecules, which shortens the H O bond but lengthens the O:H nonbond via O O Coulomb repulsion; (ii) the effect of X− electrification on the O:H O bond relaxation varies with solute type and solute concentration. Exercises not only verify the essentiality of solvent O:H O bond cooperative relaxation and polarization but also demonstrate the power of DPS that resolves processes occurred upon solvation.

A localized, metastable, 5775-type defect is uncovered in the double-layer ice with and without Au(1 1 1) support from density functional theory calculations. Without destroying the total number conservation of the hydrogen bonds in the hexagonal ice, the defect only dislocates the molecules by 0.08 A associated with a 3.27% difference of the interaction energy. The high energy barrier, low quantum tunneling and thermal transporting probabilities hindered the transformation from the 6666 to the 5775 structures. This finding indicates that the defected ice is stable, and it tends to form during the ice growth instead of post-grown process.

Solvation of acid, base, and salt is ubiquitously important to all subject areas in chemistry, health care and life science. However, fine resolution of the solvation dynamics, solute-solvent molecular interactions, and solute capability of transforming the hydrogen bond (O:H O, or HB) and surface stress remain great challenge. Incorporating the notion of O:H O bond cooperativity with a strategy of differential phonon spectroscopy (DPS) has enabled resolution on the fraction and stiffness of the solvent HB from the mode of water to the hydration shells upon NaOH, NaI and HI solvation. Results show that Na+ and I+ ionic polarization shortens the H O bond and stiffens its phonon from 3200 to 3500 cm− 1 in the hydration shells. The H+ in the HI solution forms a H ↔ H anti-HB that disrupts the solution network and surface stress. The excessive electron lone pairs of OH– form the O : ⇔ : O super-HB that compresses the network, sharing the same effect of mechanical compression shifting the H O phonon from above 3100 cm− 1 to its below; the solute H O bond performs the same to the H O dangling bond at surface featured at 3610 cm− 1. The fraction coefficients or phonon abundance transition, fH = 0, fHO ∝ C, and fx ∝ 1-exp(− C/C0) (x = Na+ and I− and C the solute concentration) towards saturation, feature the solute capability of HB transformation. Practice not only confirms the essentiality of the H ↔ H anti-HB point fragilization, the O : ⇔ : O super-HB point compression, and the ionic polarization to the performance of the respective HI, NaOH, and NaI solutions, but also demonstrate the power of the DPS that enables fine-resolution of solvation dynamics and solute capabilities.

We show phonon spectrometrically that the unprecedented H 2 O: ↔ :O:H – compression resolves the performance of the base solution networks with “:” being the electron lone pair of oxygen. At hydration, LiOH, NaOH, KOH molecules dissolve each into a :O:H – hydroxide and cations of Li + , Na + , and K + , respectively. The cations serve as charge centers to polarize the neighboring water molecules and raise the solution skin stress (or surface tension). The :O:H – tetrahedron adds, however, three lone pairs and one bonded H + proton to the solution matrix, turning the initially 2N lone pairs into 2N + 3 and the 2N bonded H + into 2N + 1 with an additional O 2– anion. This hydration process breaks the conservation of the 2N lone pairs and protons with two extra lone pairs that only can form a H 2 O: ↔ :O:H – super hydrogen bond (super-HB) with strong repulsivity. In addition to the H O bond of the :O:H – featured at 3610 cm − 1 , the internal H 2 O: ↔ :O:H – compression has an identical effect of mechanical compression, shortening the O:H nonbonds and stiffening their phonons from below 200 cm − 1 to the above. Meanwhile, compression lengthens the network H O bonds and softens their phonons from above 3150 cm − 1 to below. The network H O bonds elongation decreases their energy from ~ 4.0 to ~ 2.7 eV at hydration, which heats the solution as one often observes. The H 2 O: ↔ :O:H – super-HB compressor and the alkali cation polarizor form the keys to the base hydration networks and the properties.

A combination of the differential Raman spectrometrics and contact-angle measurements has enabled resolution of the hydrogen bond (HB, O:H O) relaxation and molecular dynamics in the NaX hydration shells. Observations suggest that the aqueous ions create each an electric field to form the hydration shells through O:H O bond elongation and polarization. The ionic polarization shares the same, and even stronger, effect of molecular undercoordination that shortens the H O bond and stiffen its phonon, and meanwhile, the O O Coulomb repulsivity lengthen and soften the O:H nonbond with an association of polarization. O:H O bond electrification raises not only the structure order of molecules and the viscosity in the hydration shells but also the skin stress and thermal stability of the solution. Exercises not only deepen our insight into the salt solute-solvent interaction involved in the Hofmeister series in terms of O:H O bond electrification but also provide a powerful means quantifying the dynamic, local, molecular-site-resolved information regarding the O:H O bond cooperativity in aqueous solutions.

Water skin is the toughest of ever known with a mechanism that remains unclear. We show phonon spectrometrically that molecular undercoordination induced hydrogen bond (O:H O) relaxation and nonbonding electron polarization furnished the skin with the supersolid nature – less dense, elastic, thermally more stable than the bulk. Heating from 5 to 95 °C stiffens the skin H O phonon (or bond stiffness) from 3443 cm− 1 by 0.38%, and the bulk phonon from 3239 cm− 1 by 1.48%, but softens the H O dangling bonds from 3604 cm− 1 by − 0.40%. Heating also changes the respective molecular structural order and phonon abundance by − 8.4/− 19.7%, 4.9/− 2.6%, and 13.0/137.0%. Observations also evidenced that both heating and molecular undercoordination have the same effect on O:H O bond relaxation but opposite on polarization, which improves our understanding of the anomalous skin of liquid water.

A systematic phonon spectrometric examination revealed that the H C phonon (2966 cm−1) undergoes blueshift under both compression and heating, but the C N (921 cm−1) and the N O (1403 cm−1) bonds undergo regular thermal redshift and compression blueshift in the Nitromethene (CH3NO2) assembly that is a solid under compression and a liquid under heating. An extension of the Gruneisen parameters integrates the phonon frequency shift to the intrinsic compressibility, thermal expansibility, specific heat, equilibrium bond length, atomic cohesive energy, and bonding energy density of the single bond which represents all of its sorts contributing to the spectral peak shift. The coupled hydrogen bond (HB, N (O):H–C), performs the same as the O:H–O of liquid water and ice I does in responding to heating. Results suggested that the combination of the N (O):H-C tension and the O:⇔:N repulsion stabilize the crystal structure and store energy, as they do in the cyclo-N5−:[4H3O+; 3H3O+ + 2NH4+] complexes.