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The resultant energy of solvent H–O bond exothermic elongation by O:⇔:O repulsion, featured at <3100 cm −1 , and the solute H–O bond endothermic contraction by bond-order-deficiency, at 3610 cm −1 , heats up the (Li, Na, K)OH solutions. The solution temperature increases linearly with the number fraction of the ordinary O:H–O bonds transiting into their hydration states. The elongated H–O bond emits >150% the O:H cohesive energy of 0.095 eV that caps the energy dissipating by molecular motion, thermal fluctuation, diffusion, and even evaporation. Therefore, the intramolecular H–O bond relaxation dictates the OH − solvation bonding thermodynamics and the performance of basic solutions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydration dissolves an organic trunk into molecular dipoles wrapped with lone pairs and protons. • Solute interacts with solvent via O:H attraction, H ↔ H and O:⇔:O repulsion, with polarization. • Polarization shortens and stiffens the H-O but the O:H responses to polarization contrastingly. • Repulsion disrupts the bonding network and surface stress by fragmentation of the solution. Interaction between an organic molecular solute and its hydrating H 2 O molecules is of great importance to processes varying from cryopreservation, denaturation of protein and DNA, and drug-cell interaction, to chemical, healthcare, and food and pharmaceutical sciences and technologies. However, the nature and functionality of the interfacial states, at the sub-molecular level, are particularly poorly known. On the views of solvation charge injection, electronic polarization, and bonding network disruption, we show experimental evidence for the interfacial supersolidity and its functionality on the performance of solutions. The asymmetrically distributed lone pairs and protons of the molecular solute interact with their unlike or alike of its hydrating H 2 O molecules to initiate the O:H attraction, H ↔ H repulsion or O:⇔:O compression associated with the molecule dipolar polarization, and solute–solute repulsion, without involvement of charge sharing or regular bond formation. Polarization lengthens the hydrating O:H and shortens the H-O, and repulsion does however the partitioned O:H-O bond contrastingly, which not only enriches the THz phonons but also results in the interfacial supersolidity characterized at H-O oscillating frequency ∼3450 cm−1. Solvation investigation of acids, alcohols, aldehydes, glycines, and sugars confirmed the prediction of the interfacial supersolidity and estimation of hydration cell size and the involvement of solute–solute repulsion. The solute dipolar polarizability distorts and the interfacial H ↔ H or O:⇔:O repulsivity disrupts the hydrogen bonding network. The bond relaxation, polarization, structure distortion, and network disruption modulate the hydrophilicity, surface stress, solubility, and solution viscosity. Findings not only improve the comprehension of the dynamics of molecular hydration and the functionality of the solutions but also offer efficient spectral means for identification and quantification of the interfacial hydration cell size and its supersolidity. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Perturbation Raman spectroscopy has underscored the hydrogen bond (O:H–O or HB) cooperativity and polarizability (HBCP) for water, which offers a proper parameter space for the performance of the HB and electrons in the energy-space-time domains. The O O repulsive coupling drives the O:H–O segmental length and energy to relax cooperatively upon perturbation. Mechanical compression shortens and stiffens the O:H nonbond while lengthens and softens the H O bond associated with polarization. However, electrification by an electric field or charge injection, or molecular undercoordination at a surface, relaxes the O:H–O in a contrasting way to the compression with derivation of the supersolid phase that is viscoelastic, less dense, thermally diffusive, and mechanically and thermally more stable. The H O bond exhibits negative thermal expansivity in the liquid and the ice-I phase while its length responds in proportional to temperature in the quasisolid phase. The O:H–O relaxation modifies the mass densities, phase boundaries, critical temperatures and the polarization endows the slipperiness of ice and superfluidity of water at the nanometer scale. Protons injection by acid solvation creates the H↔H anti-HB and introduction of electron lone pairs derives the O:⇔:O super-HB into the solutions of base or H 2 O 2 hydrogen-peroxide. The repulsive H↔H and O:⇔:O interactions lengthen the solvent H O bond while the solute H O bond contracts because its bond order loss. Differential phonon spectroscopy quantifies the abundance, structure order, and stiffness of the bonds transiting from the mode of pristine water to the perturbed states. The HBCP and the perturbative spectroscopy have enabled the dynamic potentials for the relaxing O:H–O bond. Findings not only amplified the power of the Raman spectroscopy but also substantiated the understanding of anomalies of water subjecting to perturbation. Scaling relations for the HBCP of the (a) measured segmental length and the (b) computed H O vibration frequency. [Display omitted] • O O repulsion couples the intramolecular H O and intermolecular O:H interactions. • O:H–O segmental length, energy, frequency, and specific heat parameterize water ice. • Mechanical compression shortens the O:H and lengthens the H O and polarizes water. • Electrification or molecular undercoordination effects contrastingly to compression. • DPS distills the abundance-order-stiffness transition of O:H–O driven by perturbation. [ABSTRACT FROM AUTHOR]

[Display omitted] • An ion forms a supersolid hydration cell by screened polarization of H 2 O dipoles. • Ionic polarization shortens and stiffens the H-O while does the O:H contrastingly. • A cation keeps its hydration volume invariant without being interfered by others. • Inter-anion repulsion reduces anionic hydration volume by weakening its field. • Cation/anion polarizability governs the linear/nonlinear term of Jones-Dale viscosity. 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 (±:4H 2 O:6H 2 O) hydration cell without bonding to H 2 O 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. [ABSTRACT FROM AUTHOR]