14 results on '"Chang, Q."'
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2. Liquid and Solid Skins
- Author
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Sun, Chang Q., Castleman, Albert W, Series editor, Toennies, Jan Peter, Series editor, Yamanouchi, Kaoru, Series editor, Zinth, Wolfgang, Series editor, and Sun, Chang Q
- Published
- 2014
- Full Text
- View/download PDF
3. Four-Stage Cu3O2 Bonding Dynamics
- Author
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Chang Q Sun
- Subjects
Phase transition ,Materials science ,Valence (chemistry) ,chemistry ,Annealing (metallurgy) ,Surface stress ,Desorption ,Ultimate tensile strength ,chemistry.chemical_element ,Total energy ,Oxygen ,Molecular physics - Abstract
VLLED has enabled quantification of the four-stage Cu3O2 pairing-tetrahedra formation in the Cu(001) surface transiting from O− to O2− with production of the missing rows, Cu-O-Cu chains, oppositely paired Cup crossing the missing rows. The surface stress turns from tensile in the O− derived first phase to the O2− derived second phase. The phase transition dynamics is beyond the scope of computations from the perspective of total energy minimization or structural optimization. Annealing relaxes the Cu3O2 bond geometry, the SPB, and the valence states accordingly while heating at a dull-red color de-hybridizes the sp orbits of oxygen, desorption will occur at higher temperatures.
- Published
- 2020
4. Phonon abundance-stiffness-lifetime transition from the mode of heavy water to its confinement and hydration
- Author
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Yongli Huang, Yuan Peng, Chang Q. Sun, Yi Sun, Yezi Yang, School of Electrical and Electronic Engineering, and Centre for Micro-/Nano-electronics (NOVITAS)
- Subjects
Materials science ,Solvation Bonding Dynamics ,Molecular Nonbond Interactions ,Phonon ,Ionic bonding ,02 engineering and technology ,010402 general chemistry ,Thermal diffusivity ,01 natural sciences ,Molecular dynamics ,Viscosity ,Physics::Atomic and Molecular Clusters ,Materials Chemistry ,Physical and Theoretical Chemistry ,Spectroscopy ,Quantitative Biology::Biomolecules ,Hydrogen bond ,Surface stress ,Solvation ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Chemical physics ,Electrical and electronic engineering [Engineering] ,0210 nano-technology - Abstract
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.
- Published
- 2019
5. Phonon Spectrometric Evaluation of the Solute-Solvent Interface in Solutions of Glycine and Its N-Methylated Derivatives
- Author
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Xinjuan Liu, Hengxin Fang, Chang Q. Sun, and Yongli Huang
- Subjects
Phonon ,Surface Properties ,Glycine ,Cooperativity ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Viscosity ,Materials Chemistry ,Molecule ,Physics::Chemical Physics ,Physical and Theoretical Chemistry ,Polarization (electrochemistry) ,Quantitative Biology::Biomolecules ,Hydrogen bond ,Chemistry ,Surface stress ,Water ,Hydrogen Bonding ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Surfaces, Coatings and Films ,Solvent ,Spectrophotometry ,Solvents ,Physical chemistry ,0210 nano-technology - Abstract
From the perspective of O:H-O bond cooperativity, we analyzed the solute capability of transiting the O:H-O bond from the mode of ordinary water to the hydration state and its consequence on the solution viscosity and surface stress. Phonon spectrometric results suggest that glycine and its N-methyl derivatives strongly affect the surrounding solvent molecules through H ↔ H repulsion and dipolar polarization. The H ↔ H interproton repulsion disrupts the surface stress, and the polarization enhances the solution viscosity.
- Published
- 2018
6. (H, Li)Br and LiOH Solvation Bonding Dynamics: Molecular Nonbond Interactions and Solute Extraordinary Capabilities
- Author
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Jiasheng Chen, Yongli Huang, Chang Q. Sun, Yinyan Gong, and Xi Zhang
- Subjects
Materials science ,Phonon ,Thermodynamics ,FOS: Physical sciences ,02 engineering and technology ,Condensed Matter - Soft Condensed Matter ,010402 general chemistry ,01 natural sciences ,Ion ,Viscosity ,Electric field ,Physics - Chemical Physics ,Materials Chemistry ,Physical and Theoretical Chemistry ,Physics::Chemical Physics ,Chemical Physics (physics.chem-ph) ,Quantitative Biology::Biomolecules ,Surface stress ,Solvation ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Surfaces, Coatings and Films ,Dipole ,Soft Condensed Matter (cond-mat.soft) ,0210 nano-technology ,Saturation (chemistry) - Abstract
We resolved the hydrogen bond transition from the mode of ordinary water to its hydration in terms of its phonon stiffness (vibration frequency shift), order of fluctuation (line width), and number fraction (phonon abundance) upon chage injection by solvation., 20 pages
- Published
- 2017
7. HCl, KCl and KOH solvation resolved solute-solvent interactions and solution surface stress
- Author
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Yong Zhou, Yongli Huang, Yinyan Gong, Chang Q. Sun, Xi Zhang, Yan Xu, and School of Electrical and Electronic Engineering
- Subjects
Hydrogen bond ,Chemistry ,Surface stress ,Inorganic chemistry ,Relaxation (NMR) ,Solvation ,Dangling bond ,General Physics and Astronomy ,02 engineering and technology ,Surfaces and Interfaces ,General Chemistry ,Electrolyte ,Interface ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Contact angle ,Solvent ,Hydrogen Bond ,Physical chemistry ,0210 nano-technology - Abstract
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.
- Published
- 2017
8. Water Supersolid Skin
- Author
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Yi Sun and Chang Q. Sun
- Subjects
Superfluidity ,Viscosity ,Supersolid ,Dipole ,Materials science ,Surface stress ,Thermodynamics ,Thermal stability ,Electron ,Elasticity (economics) - Abstract
Consistency in experimental observations, numerical calculations, and theoretical predictions revealed that skins of 25 °C water and −(15-20) °C ice share the same attribute of supersolidity characterized by the identical H–O vibration frequency of 3450 cm−1. Molecular undercoordination and inter-electron-pair repulsion shortens the H–O bond and lengthen the O:H nonbond, leading to a dual process of nonbonding electron polarization. This relaxation-polarization process enhances the dipole moment, elasticity, viscosity, thermal stability of these skins with 25 % density loss, which is responsible for the hydrophobicity and toughness of water skin and the superfluidity in a microchannel.
- Published
- 2016
9. Liquid and Solid Skins
- Author
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Chang Q. Sun
- Subjects
Surface (mathematics) ,Surface tension ,Mesoscopic physics ,Materials science ,Chemical physics ,Surface stress ,Energetics ,Cohesive energy ,Surface energy - Abstract
Surface energetics, including the terms of surface energy, surface free energy, surface tension, surface stress, and their correlations, plays the central role in surface and nanosolid sciences. Despite confusions about these terms, the surface energetics is of great importance to a qualitative and sometimes even quantitative understanding of the microscopic and mesoscopic processes at a surface of liquid or solid.
- Published
- 2014
10. Aqueous charge injection: solvation bonding dynamics, molecular nonbond interactions, and extraordinary solute capabilities.
- Author
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Sun, Chang Q.
- Subjects
- *
SOLVATION , *AQUEOUS solutions , *CHEMICAL bonds , *MOLECULAR magnetic moments , *ELECTRIC potential - Abstract
Aqueous charge injection in forms of electrons, protons, lone pairs, ions, and molecular dipoles by solvation is ubiquitously important to our health and life. Pursuing fine-resolution detection and consistent insight into solvation dynamics and solute capabilities has become an increasingly active subject. This treatise shows that charge injection by solvation mediates the O:H-O bonding network and properties of a solution through O:H formation, H↔H fragilization, O:⇔:O compression, electrostatic polarization, H2O dipolar shielding, solute-solute interaction, and undercoordinated H-O bond contraction. A combination of the hydrogen bond (O:H-O or HB with ':' being the electron lone pairs of oxygen) cooperativity notion and the differential phonon spectrometrics (DPS) has enabled quantitative information on the following: (i) the number fraction and phonon stiffness of HBs transiting from the mode of ordinary water to hydration; (ii) solute-solvent and solute-solute molecular nonbond interactions; and (iii) interdependence of skin stress, solution viscosity, molecular diffusivity, solvation thermodynamics, and critical pressures and temperatures for phase transitions. An examination of solvation dynamics has clarified the following: (i) the excessive protons create the H↔H or anti-HB point breaker to disrupt the acidic solution network and surface stress. (ii) The excessive lone pairs generate the O:⇔:O or super-HB point compressor to shorten the O:H nonbond but lengthen the H-O bond in H2O2 and basic solutions; yet, bond-order-deficiency shortens and stiffens the H-O bond due H2O2 and OH− solutes. (iii) Ions serve each as a charge center that aligns, clusters, stretches, and polarizes their neighboring HBs to form hydration shells. (iv) Solvation of alcohols, aldehydes, complex salts, carboxylic and formic acids, glycine, and sugars distorts the solute-solvent interface structures with the involvement of the anti-HB or the super-HB. Extending the knowledge and strategies to catalysis, solution-protein, drug-cell, liquid-solid, colloid-matrix interactions and molecular crystals would be even more fascinating and rewarding. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
11. Atomistic origin, temperature dependence, and responsibilities of surface energetics: An extended broken-bond rule
- Author
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Zi Wen, Weitao Zheng, Mingxia Gu, Ming Zhao, Chang Q. Sun, and Jian-Chen Li
- Subjects
Surface (mathematics) ,Materials science ,Structural stability ,Chemical physics ,Surface stress ,Atom ,Physical chemistry ,Bond energy ,Condensed Matter Physics ,Bond order ,Surface energy ,Thermal expansion ,Electronic, Optical and Magnetic Materials - Abstract
There has long been confusion regarding the origin and temperature dependence of surface energetics and its responsibility for the processes and phenomena at a surface. From the perspective of bonds broken and its consequences on the remaining bonds of the undercoordinated surface atoms, we suggested herewith two essential concepts supplementing to the existing definition of surface energy for clarification purposes. One is the energy-density-gain per unit volume in surface skin and the other is the remaining cohesive-energy per discrete atom upon bond order loss once the surface is formed. The former governs the strength and elasticity while the latter dominates the thermal and structural stability of the surface. The shortened and strengthened bonds between the undercoordinated atoms dictate surface energetics and the effects of thermal expansion and vibration dominate their temperature dependence. Reproduction of the measured size and temperature dependency has led to information about the bond energy, which may go beyond traditional approaches and evidence the validity of the approaches.
- Published
- 2007
12. HCl, KCl and KOH solvation resolved solute-solvent interactions and solution surface stress.
- Author
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Zhou, Yong, Zhang, Xi, Sun, Chang Q, Gong, Yinyan, Xu, Yan, and Huang, Yongli
- Subjects
- *
HYDROGEN bonding , *HYDROCHLORIC acid , *SOLVATION , *ELECTROLYTES , *SURFACE analysis , *MOLECULAR interactions - Abstract
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 < 3100 cm −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. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
13. Molecular hydration: Interfacial supersolidity and its functionality.
- Author
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Fang, Hengxin, Wang, Xuejie, Zhou, Yong, Zhang, Chenxu, Tan, Tingyuan, Yao, Chuang, Huang, Yongli, Wang, Biao, and Sun, Chang Q
- Subjects
- *
HYDRATION , *DENATURATION of proteins , *DNA denaturation , *CHARGE injection , *CELL size , *SOLVATION - Abstract
[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]
- Published
- 2024
- Full Text
- View/download PDF
14. NaX solvation bonding dynamics:hydrogen bond and surface stress transition (X = HSO4, NO3, ClO4, SCN).
- Author
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Zhou, Yong, Zhong, Yuan, Liu, Xinjuan, Huang, Yongli, Zhang, Xi, and Sun, Chang Q.
- Subjects
- *
HYDROGEN bonding , *SOLVATION , *STRAINS & stresses (Mechanics) , *SODIUM compounds , *RAMAN spectroscopy , *SOLUTION (Chemistry) - Abstract
Raman phonon differential spectrometrics (DPS) and contact angle measurements resolved that solvation of the NaX (X = HSO 4 , NO 3 , ClO 4 , 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, f NaX (C) ∝ 1-exp(− C/C 0 ) towards saturation, with C being the solute concentration and C 0 the decay constant. Observations evidence that: (i) the solute ionic field electrification aligns, stretches, and polarizes its neighboring H 2 O 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. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
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