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Bond relaxation from one equilibrium to another under perturbation matters uniquely the performance of a substance and thus it has enormous impact to materials science and engineering. However, the basic rules for the perturbation-bond-property correlation and efficient probing strategies for high-resolution detection stay yet great challenge. This treatise features recent progress in this regard with focus on the multifield bond oscillation notion and the theory-enabled phonon spectrometrics. From the perspective of Fourier transformation and the Taylor series of the potentials, we correlate the phonon spectral signatures directly to the transition of the characteristic bonds in terms of stiffness (frequency shift), number fraction (integral of the differential spectral peak), structure fluctuation (linewidth), and the macroscopic properties of the substance. A systematic examination of the spectral feature evolution for group IV, III-V, II-VI crystals, layered graphene nanoribbons, black phosphor, (W, Mo)(S2, Se2) flakes, typical nanocrystals, and liquid water and aqueous solutions under perturbation has enabled the ever-unexpected information on the perturbation-bond-property regulations. Consistency between predictions and measurements of the crystal size-resolved phonon frequency shift clarifies that atomic dimer oscillation dictates the vibration modes showing blueshift while the collective vibration of oscillators formed between a certain atom and its nearest neighbors governs the modes of redshift when the sample size is reduced. Theoretical matching to the phonon frequency shift due to atomic undercoordination, mechanical and thermal activation, and aqueous charge injection by solvation has been realized. The reproduction of experimental measurements has turned out quantitative information of bond length, bond energy, single bond force constant, binding energy density, vibration mode activation energy, Debye temperature, elastic modulus, and the number and stiffness transition of bonds from the mode of references to the conditioned upon perturbation. Findings prove not only the essentiality of the multifield lattice oscillating dynamics but also the immense power of the phonon spectrometrics in revealing the bond-phonon-property correlation of solid and liquid substance.

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.

Overdosing of Na(Cl, C5H8NO4) can raise one's blood pressure but moderately intaking of C6H8O6 ascorbic and C2H4O2 acetic acids effects contrastingly with mechanisms yet to be clear. From the perspective of hydrogen bond (O:H O or HB with “:” being electron lone pairs of oxygen) cooperativity, we show phonon-spectrometrically that solvation of the Na-based doses raises their solution surface tension by ionic polarization, but solvation of the organic acids performs contrastingly by dipolar fragilization. The Na-based doses dissolve into Na+ cations and anions that serve each as a charge center to cluster, stretch, and polarize the solvent O:H O bonds, raising the viscosity of the solution. However, the acidic dipoles break the solvation network into small fragments, helping to the blood flowing. Findings could offer workable mechanisms for hypertension medication and prevention.

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.

We proposed a mechanism to induce strong magnetism of up to 10.92 emu g-1 in hexagonal-phase arsenene nanoribbon (AsNR) from the perspective of edge quantum entrapment. Consistency between bond-order-length-strength correlation (BOLS) theory and density functional theory (DFT) calculations verified that: (i) the edge bond contraction of 9.54% deepened the edge potential well of AsNR, (ii) a net charge of 0.06 e- transferred from the inner region to the edge; and (iii) the edge quantum well polarized the unpaired electron and the net spin (antiferromagnetic or ferromagnetic depending on the width) is localized at the zigzag edge. The finding sheds a light on applications of AsNR in magnetic storage devices.

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

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.

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.

A combination of photoelectron spectrometric analysis and density functional theory calculations has enabled reconciliation of the bond-energy-electron relaxation for the Ta(100, 110, 111) surfaces chemisorbed with oxygen at different coverages. Results show that increasing oxygen coverage lowers the adsorption energy associated with lattice reconstruction. Valence electrons transfer from Ta surface atoms to oxygen to create four excessive DOS features in terms of O Ta bonding, lone pairs of oxygen, Ta+ electron holes, and polarized Ta dipoles. Oxidation proceeds in the following dynamics: oxygen gets electrons from two neighboring Ta atoms left behind Ta+; the sp3-orbital hybridization takes place with additional two electron lone pairs, the lone pairs polarize the other two Ta neighbors becoming dipoles. X-ray photoelectron spectral analysis results in the 4f binding energy of an isolated Ta atom and its shift upon bond formation and oxidation. Exercises provide not only a promising numerical approach for the quantitative information about the bond and electronic behavior but also consistent insight into the electronic dynamics of metal oxidation.

The presence of the nonbonding XH tension constrains and the presence of the anti or super hydrogen bond fosters the explosion in aqueous alkali and molten alkali halides; the combination of the coupled hydrogen bond and the repulsive anti or super hydrogen bond not only stabilzes the structure but also stores energy of the energetic molecular assemblies by shortening all covalent bonds., Comment: 4 figure, 3500 works

The inter oxygen repulsion opposes compression minimizing the compressibility. Polarization enlarges the bandgap and the dielectric permittivity of water ice by raising the nonbonding states above the Fermi energy. Progress evidences the efficiency and essentiality of the coupled hydrogen bonding and electronic dynamics in revealing the core physics and chemistry of water ice, which could extend to other molecular crystals such as energetic materials., Comment: 15 k words, 118 refs, 17 figures

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.

We show the reconciliation of the strain (e)-, pressure (P)-, and layer-number (N)-dependence of the phonon frequency and photon energy shifts for MX2 in terms of stimulated bond relaxation, with quantification of the coefficients of bond length and energy relaxation, the bond nature index, force constant, and cohesive energy density. We found that (i) atomic under-coordination shortens and stiffens the M–X bond, which widens the bandgap; (ii) the directional strain governs phonon-frequency splitting and narrowing; and (iii) homogenous mechanical compression induces the opposite effect of stretching.

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.

Albeit its chemical inertness, rare gas doping can substantially enhance the quantum size effect of nanocrystals, yet little attention has been paid on this fascination and the mechanism behind remains unclear. Here, we show that the rare gas dopant breaks bonds of its neighboring atoms, which effects the same to atomic under-coordination on the bond strain, energy quantum entrapment, and valence electron polarization of Li and Na clusters. Consistency between density functional theory calculation and the bond-order-length-strength correlation prediction revealed that the bond strain by 16.86% and 21.12% before and after He doping for Na30 clusters. Observations suggest an effective yet simple means to modulate the physical properties by doping the inert gases.

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.

We systematically examined the effects of number-of-layer, pressure, and temperature on the bond length and energy, Debye temperature, atomic cohesive energy, and binding energy density for layered black phosphorus using bond–phonon–photon spectrometric methods. We clarified the following: (1) atomic under-coordination shortens and stiffens the PP bond, which raises the B2g and Ag2 phonon frequency and widens the bandgap, (2) bond thermal elongation and weakening soften all phonon modes, and (3) bond mechanical compression has the opposite effect of heating on phonon frequency relaxation. The phonon and photon energy depends on the bond length and energy, which determines the relevant elasticity and thermal stability of layered structure. More broadly, the approaches and findings of this work provide both insight into and efficient tools for further exploration of unusual behaviors of other two-dimensional substance. Copyright © 2016 John Wiley & Sons, Ltd.

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.

A combination of the spatially- and temporally-resolved phonon spectroscopies has enabled calibration of hydrogen bond transition from the vibration mode of heavy water to the core-shell structured nanodroplets and to the ionic hydration shells of salt solutions in terms of phonon abundance-lifetime-stiffness. It is uncovered that charge injection by salt solvation and skin formation by molecular undercoordination (often called confinement) share the same supersolidity characterized by H–O (D–O as a probe) bond contraction, O:H nonbond elongation, and polarization. Such a process of bond transition stems the solution viscosity, surface stress, and slowing down of the molecular dynamics and diffusivity. The nanodroplet skin reflection further hinders phonon energy dissipation associated with longer D–O phonon lifetime. Financial support received from National Natural Science Foundation of China (Nos. 11872052(YL); 21875024(CQ)), the Science Challenge Project (No. TZ2016001) of China is acknowledged.

It is fascinating that heating softens not only the photon bandgap energies but also the A1g and E12g phonon frequencies of the few-layered MX2 (M = Mo, W and X = S, Se) semiconductors, yet a common mechanism behind remains challenging. With the aid of Raman phonon scattering and photon absorption spectrometrics, we have been able to correlate and formulate these observations from the perspective of interatomic bond thermal relaxation. Reproduction of measurements clarified that the photon energy relaxation depends on the response of bond energy to thermal excitation, and the phonon frequency varies with the bond stiffness—a function of length and energy. Besides, theoretical matching to experimental observations has derived the Debye temperatures of the specifically layered nanostructures and the atomic cohesive energy of their bulk counterparts as well. The electronegativity difference between the M and X in each case discriminates the rate of their bandgap energy and phonon frequency relaxation.

We have examined the atomic coordination effect on the local bond strain and the 3p core-level shift of K(1 1 0) skin and nanoclusters using a combination of the bond order–length–strength correlation notion, tight-binding approach, density functional theory calculations, and photoelectron spectroscopy measurements. It turns out that: (i) the 3p core-level shifts from 15.595 ± 0.003 eV for an isolated K atom by 2.758 eV to the bulk value of 18.353 eV; (ii) the effective atomic coordination number reduces from the bulk value of 12 to 3.93 for the first layer and to 5.81 for the second layer of K(1 1 0) skin associated with the local lattice strain of 12.76%, a binding energy density 72.67%, and atomic cohesive energy −62.46% for the skin; and (iii) K cluster size reduction lowers the effective atomic coordination number and enhances further the skin electronic attribution. Results have revealed that the 3p core-level shifts of K(1 1 0) and nanoclusters originate from perturbation of the Hamiltonian by under-coordination induced charge densification and quantum entrapment.

This presentation features recent progress in understanding the phase diagram of water and ice from the perspective of hydrogen bond (O:H–O) cooperative relaxation with focus on how the segmental length and the containing angle of the O:H–O bond change with mechanical compression and thermal excitation. By interplaying theoretical predictions, numerical computations, and phonon spectrometrics, we firstly examined the relaxation dynamics of O:H–O bond segmental length and phonon stiffness of: i) liquid water at 300 K and ice at 80 K as a function of pressure, ii) liquid water cooling from 350 K to 80 K under the ambient pressure, iii) mechanical freezing of the ambient water under compression up to 1.83 GPa, and, iv) liquid water heating from 253 to 753 K under 30 MPa pressure. Observations allow us to classify the TC(P) phase boundaries of water and ice into four types according to their slopes and then formulate them in terms of hydrogen bond relaxation in segmental length and containing angle. Observations reinforce the essentiality and effectiveness of hydrogen bond notion in dictating the unusual behavior of water and ice and clarify the bonding dynamics during phase transition, which is beyond the scope of classical thermodynamics.

Combining the bond-order-length-strength corrected tight-binding (BOLS-TB) theory and the density functional theory (DFT) calculation, we clarified the energetic origin of the width-dependent band gap (Eg) expansion of the zigzag and armchair-edged antimonene nanoribbons (SbNRs) terminated by atomic hydrogen. Consistency between the density-function theory calculations and the BOLS-TB prediction affirmed that: (i) the Eg expansion originates from the Hamiltonian correction due to the size-dependent undercoordination effect; (ii) both the contraction of the ribbon up to 11% and the edge quantum trapping of charge of 0.05e determine the width dependent Eg change; and, (iii) Under-coordination induced quantum entrapment in the armchair SbNRs is stronger than that of zigzag SbNRs, resulting in larger Eg (∼0.3–0.6eV higher). Hence, the physical origin for the modulation of Eg (1.2–3.1 eV) by edge quantum entrapment or by other under-coordinated sites will benefit the Eg engineering of antimonene for wide electro-optical applications.

Consistency between density functional theory calculations and photoelectron spectroscopy measurements confirmed our predications on the undercoordination-induced local bond relaxation and core level shift of Na and K clusters. It is clarified that the shorter and stronger bonds between under-coordinated atoms cause local densification and local potential well depression and shift the electron binding-energy accordingly. Numerical consistency turns out the energy levels for an isolated Na ( E 2p = 31.167 eV) and K ( E 3p = 18.034 eV) atoms and their respective bulk shifts of 2.401 eV and 2.754 eV, which is beyond the scope of conventional approaches. This strategy has also resulted in quantification of the local bond length, bond energy, binding energy density, and atomic cohesive energy associated with the undercoordinated atoms.

Numerical reproduction of the measured 4f7/2 energy shift of Ir(1 0 0), (1 1 1), and (2 1 0) solid skins turns out the following: (i) the 4f7/2 level of an isolated Ir atom shifts from 56.367 eV to 60.332 eV by 3.965 eV upon bulk formation; (ii) the local energy density increases by up to 130% and the atomic cohesive energy decreases by 70% in the skin region compared with the bulk values. Numerical match to observation of the temperature dependent energy shift derives the Debye temperature that varies from 285.2 K (Surface) to 315.2 K (Bulk). We clarified that the shorter and stronger bonds between under-coordinated atoms cause local densification and quantum entrapment of electron binding energy, which perturbs the Hamiltonian and the core shifts in the skin region.

From the perspective of bond order-length-strength correlation, we have formulated the Raman phonon relaxation dynamics of CdSe nanocrystals in terms of the length and energy response of the representative bond for all of the entire specimen to the change of crystal shape, size, and the heating conditions. In addition to quantification of the bond length, bond energy, atomic cohesive energy, thermal expansion coefficient, and average coordination numbers of CdSe nanostructures in various shapes, consistency between theory predictions and measurements clarifies that the bond relaxation due to heating and bond-order reduction is responsible for the frequency shift of the CdSe lattice vibration.

An incorporation of the hydrogen bond (O:H O or HB) cooperativity notion, contact angle detection, and the differential phonon spectrometrics (DPS) has enabled us to gain refined information on the HCl, KCl and KOH solvation resolved solute-solvent molecular interactions and the solution surface stresses. Results show that ionic polarization stiffens the solvent H O bond phonon from 3200 to 3480 cm −1 in the hydration shells. The HO − in alkaline solution, however, shares not only the same H O phonon redshift of compressed water from 3200 to −1 but also the dangling bonds of H 2 O surface featured at 3610 cm −1 . Salt and alkaline solvation enhances the solution surface stress by K + and Cl − ionic polarization. The excessive H + proton in acid solution forms a H↔H anti-HB that depresses the solution surface stress, instead. The solute capability of transforming the fraction of the O:H O bonds of the solvent matrix is featured by: f H = 0 and f x ∝ 1-exp(-C/C 0 ) (x = HO − , K + and Cl − ) towards saturation. Exercises not only confirm the presence of the H↔H anti-HB point fragilization, the O:⇔:O super-HB point compression, and ionic polarization dominating the performance of the respective HCl, KOH, and KCl solutions, but also demonstrate the power of the DPS that enables high resolution of solute-solute-solvent interactions and correlation between HB relaxation and solution surface stress.

a b s t r a c t We present an approach for quantifying the heterogeneous interface bond energy using X-ray photo- electron spectroscopy (XPS). Firstly, from analyzing the XPS core-level shift of the elemental surfaces we obtained the energy levels of an isolated atom and their bulk shifts of the constituent elements for ref- erence; then we measured the energy shifts of the specific energy levels upon interface alloy formation. Subtracting the referential spectrum from that collected from the alloy, we can distil the interface effect on the binding energy. Calibrated based on the energy levels and their bulk shifts derived from elemental surfaces, we can derive the bond energy, energy density, atomic cohesive energy, and free energy at the interface region. This approach has enabled us to clarify the dominance of quantum entrapment at CuPd interface and the dominance of polarization at AgPd and BeW interfaces, as the origin of interface energy change. Developed approach not only enhances the power of XPS but also enables the quantification of the interface energy at the atomic scale that has been an issue of long challenge.

Water nanobubbles manifest fascinatingly higher mechanical strength, higher thermal stability, and longer lifetime than macroscopic bubbles; thus, they provide an important impact in applications in the biomedical and chemical industries. However, a detailed understanding of the mechanism behind these mysteries of nanobubbles remains a challenge. Consistency between quantum computations and Raman spectrometric measurements confirmed our predictions that a nanobubble skin shares the same supersolidity with molecular clusters, skins of bulk water, and water droplets because of molecular undercoordination (fewer than four nearest molecular neighbors). Molecular undercoordination (coordination number Zcluster < Zsurface < Zbubble < Zbulk = 4) shortens/extends the H–O/O:H bond and stiffens/softens its corresponding stretching phonons, whose frequency shift is proportional to the square root of the cohesive energy and inversely proportional to the segmental length. The strongly polarized O:H–O bond slows the mo...

To characterize the elastic-plastic properties of thin film materials on elastic-plastic substrates, a simple theory model was proposed, which included three steps: dimensionless analysis, finite element modeling and data fitting. The dimensionless analysis was applied to deriving two preliminary nondimensional relationships of the material properties, and finite element modeling and data fitting were carried out to establish their explicit forms. Numerical indentation tests were carried out to examine the effectiveness of the proposed model and the good agreement shows that the proposed theory model can be applied in practice.

Using ab initio calculation coupled with the bond-order-length-strength (BOLS) approximation, we investigate the configurations and electronic properties of (α, β)-graphyne nanoribbons (GYNRs) with armchair (AGYNRs) and zigzag (ZGYNRs) edges. Our investigation shows that the armchair-edged β-GYNRs and all α-GYNRs are semiconductors with suitable band-gaps, and that their band-gaps increase as the widths of nanoribbons decrease; on the other hand, zigzag-edged β-GYNRs appear to be zero-band-gap materials. Observation results suggest that (i) atomic undercoordination shortens and stiffens the C–C bond, which contributes to the Hamiltonian and hence widens the band-gap intrinsically; (ii) zigzag-edged β-GYNRs lack a band-gap due to the edge-undercoordinated atoms lacking the energy to open the β-graphyne gap; and (iii) the edge-undercoordination of atoms occurs during charge entrapment. Published version

Nanocrystalline nickel films of 17–40 nm grain sizes were prepared using pulsejet electrodeposition. Structure, corrosion and lattice strain were analysed by transmission electron microscope, electrochemical workstation and X-ray diffraction, revealing that with decreasing of grain size, the lattice strain, corrosion rate of the films are enhanced. The observations can be consistently understood in terms of the bond-order-length-strength correlation mechanism indicating that the shortened and strengthened bonds between the under-coordinated atoms modify the energy density and the atomic cohesive energy in the surface skins of the grains. The surface energy density gain is responsible for the residual atomic cohesive energy for the activation energy of corrosion. Additionally, a novel algorithm was proposed to extract the elastic-plastic properties of nickel films and results that the nickel film has much higher yield strength than bulk nickel.

Clarifying the origin for surface core-level shift (SCLS) and gaining quantitative information regarding the coordination-resolved local strain, binding energy (BE) shift and cohesive energy change have been a challenge. Here, we show that a combination of the bond order–length–strength (BOLS) premise, X-ray photoelectron spectroscopy (XPS) and the ab initio density functional theory (DFT) calculations of aluminum (Al) [Formula: see text] energy shift of Al surfaces has enabled us to derive such information, namely, (i) the [Formula: see text] energy of an isolated Al atom [Formula: see text] and its bulk shift (0.499 eV); (ii) the skin lattice contracts by up to 12.5% and the BE density increases by 70%; and (iii) the cohesive energy drops up to 38%. It is affirmed that the shorter and stronger bonds between under-coordinated atoms provide a perturbation to the Hamiltonian and hence lead to the local strain, quantum entrapment and valence charge polarization. Findings should help in understanding the phenomena of surface pre-melting and skin-high elasticity, in general.

Atomic-undercoordination-induced local bond contraction, bond strength gain, and the associated temperature (T)-dependent atomic-cohesive-energy and binding-energy-density are shown to originate intrinsically the exotic paradox of superplasticity, superelasticity, and superrigidity demonstrated by solid sizing from monatomic chain to mesoscopic grain. The paradox follows these relationships: $$\left. \begin{gathered} \varepsilon (K,T) \hfill \\ y(K,T) \hfill \\ \sigma (K,T) \hfill \\ \end{gathered} \right\} \propto \left\{ \begin{gathered} \exp \left( {{B \mathord{\left/ {\vphantom {B {\Delta T}}} \right. \kern-\nulldelimiterspace} {\Delta T}}_{mk} } \right), (Plastic strain) \hfill \\ \left( {\eta _1 \Delta T_{mk} } \right)d^{ - 3} , (Elastic modulus) \hfill \\ \left[ {1 + AK^{ - {1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} \exp \left( {{{\Delta T_{mk} } \mathord{\left/ {\vphantom {{\Delta T_{mk} } T}} \right. \kern-\nulldelimiterspace} T}} \right)} \right]\Delta T_{mk} d^{ - 3} , (Yield stress, IHPR) \hfill \\ \end{gathered} \right. $$ where A, B, η 1, d and ΔT mk = T m (K)−T are size (K)-dependent physical parameters. T m(K) is the melting point. Mechanical work hardening during compressing and self-heating during stretching modulate the measured outcome extrinsically. Superplasticity dominates in the solid-quasimolten-liquid transition state. The competition between the accumulation and annihilation of dislocations activates the inverse Hall-Petch relationship. Therefore, it is essential for one to discriminate the intrinsic competition between the local bond energy density gain and the atomic cohesive energy loss from the extrinsic factors of pressure and temperature in dealing with atomistic mechano-thermo dynamics.

This paper presents a method to provide electrical connection to a 2D capacitive micromachined ultrasonic transducer (CMUT) array. The interconnects are processed after the CMUTs are fabricated on the front side of a silicon wafer. Connections to array elements are made from the back side of the substrate via highly conductive silicon pillars that result from a deep reactive ion etching (DRIE) process. Flip-chip bonding is used to integrate the CMUT array with an integrated circuit (IC) that comprises the front-end circuits for the transducer and provides mechanical support for the trench-isolated array elements. Design, fabrication process and characterization results are presented. The advantages when compared to other through-wafer interconnect techniques are discussed.

Incorporating the bond order-length-strength (BOLS) notion with the Ising premise, we have modeled the size dependence of the Neel transition temperature (TN) of antiferromagnetic nanomaterials. Reproduction of the size trends reveals that surface atomic undercoordination induces bond contraction, and interfacial hetero-coordination induces bond nature alteration. Both surface and interface of nanomaterials modulate the TN by adjusting the atomic cohesive energy. The TN is related to the atomic cohesive/exchange energy that is lowered by the coordination number (CN) imperfection of the undercoordinated atoms near the surface and altered by the changed bond nature of epitaxialinterface. A numerical match between predictions and measurements reveals that the TN of antiferromagnetic nanomaterials declines with reduced size and increases with both the strengthening of heterogeneous bond and the increase of the bond number. Published version

Superlubricity means non-sticky and frictionless when two bodies are set contacting motion. Although this occurrence has been extensively investigated since 1859 when Faraday firstly proposed a quasiliquid skin on ice, the mechanism behind the superlubricity remains uncertain. This report features a consistent understanding of the superlubricity pertaining to the slipperiness of ice, self-lubrication of dry solids, and aqueous lubricancy from the perspective of skin bond-electron-phonon adaptive relaxation. The presence of nonbonding electron polarization, atomic or molecular undercoordination, and solute ionic electrification of the hydrogen bond as an addition, ensures the superlubricity. Nonbond vibration creates soft phonons of high magnitude and low frequency with extraordinary adaptivity and recoverability of deformation. Molecular undercoordination shortens the covalent bond with local charge densification, which in turn polarizes the nonbonding electrons making them localized dipoles. The locally pinned dipoles provide force opposing contact, mimicking magnetic levitation and hovercraft. O:H−O bond electrification by aqueous ions has the same effect of molecular undercoordination but it is throughout the entire body of the lubricant. Such a Coulomb repulsivity due to the negatively charged skins and elastic adaptivity due to soft nonbonding phonons of one of the contacting objects not only lowers the effective contacting force but also prevents charge from being transited between the counterparts of the contact. Consistency between theory predictions and observations evidences the validity of the proposal of interface elastic Coulomb repulsion that serves as the rule for the superlubricity of ice, wet and dry frictions, which also reconciles the superhydrophobicity, superlubricity, and supersolidity at contacts.