The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
X X Yang - One of the best experts on this subject based on the ideXlab platform.
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raman spectroscopic determination of the length energy Debye Temperature and compressibility of the c c bond in carbon allotropes
Chemical Physics Letters, 2013Co-Authors: Yan Wang, X X Yang, J W Li, Z F Zhou, W T Zheng, J Z PengAbstract:Raman phonon relaxation dynamics in carbon allotropes including graphene, carbon nanotube, C60, carbon nanobud, graphite, and diamond has been formulated in terms of the bond order–length–strength (BOLS) correlation. The length and energy responses of the representative bond to the change of coordination environment, pressure, and Temperature determine intrinsically the Raman shifts. Reproduction of the measured results in quantitative information of the bond length, bond energy, mode cohesive energy, binding energy density, Debye Temperature, and the compressibility of the C–C bond in each phase without needing involvement of the phonon scattering resonant processes or the mode Gruneisen constants. 2013 Elsevier B.V. All rights reserved.
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raman spectroscopy determination of the Debye Temperature and atomic cohesive energy of cds cdse bi2se3 and sb2te3 nanostructures
Journal of Applied Physics, 2012Co-Authors: X X Yang, Y Wang, Z F Zhou, R Jiang, W T ZhengAbstract:We have formulated the size and Temperature dependence of the phonon relaxation dynamics for CdS, CdSe, Bi2Se3, and Sb2Te3 nanostructures based on the framework of bond order–length–strength correlation, core-shell configuration, and local bond averaging approach. The Raman shifts are correlated directly to the identities (nature, order, length, and energy) of the representative bond of the specimen without needing involvement of the Gruneisen mode parameters or considering the processes of phonon decay or multi-phonon resonant scattering. Quantitative information of the Debye Temperature, the atomic cohesive energy, the reference frequencies from which the Raman shifts proceed, and the effective coordination numbers of the randomly sized particles, as well as the length and energy of the representative bond, has been obtained. It is clarified that the size-induced phonon softening arises intrinsically from the cohesive weakening of the undercoordinated atoms in the skin up to three atomic layers and the ...
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raman spectroscopic determination of the length strength compressibility Debye Temperature elasticity and force constant of the c c bond in graphene
Nanoscale, 2012Co-Authors: X X Yang, J W Li, Zhaofeng Zhou, Y Wang, Liwen Yang, Weitao ZhengAbstract:From the perspective of bond relaxation and bond vibration, we have formulated the Raman phonon relaxation of graphene, under the stimuli of the number-of-layers, the uni-axial strain, the pressure, and the Temperature, in terms of the response of the length and strength of the representative bond of the entire specimen to the applied stimuli. Theoretical unification of the measurements clarifies that: (i) the opposite trends of the Raman shifts, which are due to the number-of-layers reduction, of the G-peak shift and arises from the vibration of a pair of atoms, while the D- and the 2D-peak shifts involve the z-neighbor of a specific atom; (ii) the tensile strain-induced phonon softening and phonon-band splitting arise from the asymmetric response of the C3v bond geometry to the C2v uni-axial bond elongation; (iii) the thermal softening of the phonons originates from bond expansion and weakening; and (iv) the pressure stiffening of the phonons results from bond compression and work hardening. Reproduction of the measurements has led to quantitative information about the referential frequencies from which the Raman frequencies shift as well as the length, energy, force constant, Debye Temperature, compressibility and elastic modulus of the C‐C bond in graphene, which is of instrumental importance in the understanding of the unusual behavior of graphene.
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raman spectroscopic determination of the length strength compressibility Debye Temperature elasticity and force constant of the c c bond in graphene
arXiv: Mesoscale and Nanoscale Physics, 2011Co-Authors: X X Yang, Yan Wang, Changqing Sun, Zhaofeng Zhou, Liwen Yang, Weitao ZhengAbstract:From the perspective of bond relaxation and vibration, we have reconciled the Raman shifts of graphene under the stimuli of the number-of-layer, uni-axial-strain, pressure, and Temperature in terms of the response of the length and strength of the representative bond of the entire specimen to the applied stimuli. Theoretical unification of the measurements clarifies that: (i) the opposite trends of Raman shifts due to number-of-layer reduction indicate that the G-peak shift is dominated by the vibration of a pair of atoms while the D- and the 2D-peak shifts involves z-neighbor of a specific atom; (ii) the tensile strain-induced phonon softening and phonon-band splitting arise from the asymmetric response of the C3v bond geometry to the C2v uni-axial bond elongation; (iii) the thermal-softening of the phonons originates from bond expansion and weakening; and (iv) the pressure- stiffening of the phonons results from bond compression and work hardening. Reproduction of the measurements has led to quantitative information about the referential frequencies from which the Raman frequencies shift, the length, energy, force constant, Debye Temperature, compressibility, elastic modulus of the C-C bond in graphene, which is of instrumental importance to the understanding of the unusual behavior of graphene.
Changqing Sun - One of the best experts on this subject based on the ideXlab platform.
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coordination resolved local bond relaxation electron binding energy shift and Debye Temperature of ir solid skins
Applied Surface Science, 2014Co-Authors: Yan Wang, Yongli Huang, Xuexian Yang, Yezi Yang, Changqing SunAbstract:Abstract 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.
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raman spectroscopic determination of the length strength compressibility Debye Temperature elasticity and force constant of the c c bond in graphene
arXiv: Mesoscale and Nanoscale Physics, 2011Co-Authors: X X Yang, Yan Wang, Changqing Sun, Zhaofeng Zhou, Liwen Yang, Weitao ZhengAbstract:From the perspective of bond relaxation and vibration, we have reconciled the Raman shifts of graphene under the stimuli of the number-of-layer, uni-axial-strain, pressure, and Temperature in terms of the response of the length and strength of the representative bond of the entire specimen to the applied stimuli. Theoretical unification of the measurements clarifies that: (i) the opposite trends of Raman shifts due to number-of-layer reduction indicate that the G-peak shift is dominated by the vibration of a pair of atoms while the D- and the 2D-peak shifts involves z-neighbor of a specific atom; (ii) the tensile strain-induced phonon softening and phonon-band splitting arise from the asymmetric response of the C3v bond geometry to the C2v uni-axial bond elongation; (iii) the thermal-softening of the phonons originates from bond expansion and weakening; and (iv) the pressure- stiffening of the phonons results from bond compression and work hardening. Reproduction of the measurements has led to quantitative information about the referential frequencies from which the Raman frequencies shift, the length, energy, force constant, Debye Temperature, compressibility, elastic modulus of the C-C bond in graphene, which is of instrumental importance to the understanding of the unusual behavior of graphene.
Qing Jiang - One of the best experts on this subject based on the ideXlab platform.
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size effects on cohesive energy Debye Temperature and lattice heat capacity from first principles calculations of sn nanoparticles
Proceedings of the National Academy of Sciences India Section A: Physical Sciences, 2018Co-Authors: Botan Jawdat Abdullah, M S Omar, Qing JiangAbstract:The size-dependent cohesive energy, melting Temperature, Debye Temperature and lattice heat capacity are investigated using density functional theory within generalized gradient approximation of Sn nanoparticles. The analyses of the obtained total energies are presented by considering effect of mean bond length and the ratio number of surface atoms to that of its internal with size. The cohesive energy is calculated for Sn nanoparticles and the obtained data are used to determine melting Temperature, Debye Temperature and lattice heat capacity. The cohesive energy, melting point and Debye Temperature drop while the lattice specific heat rise when the size is decreased due to the effects of the elevated bond length stretch. The results obtained are in excellent agreement with the available experimental results for melting point and Debye Temperature of Sn nanoparticles. Also, the same trend variations of the lattice heat capacity obtained for Sn nanoparticles to that calculated theoretically in Se and Cu.
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correction to modeling of the melting point Debye Temperature thermal expansion coefficient and the specific heat of nanostructured materials
Journal of Physical Chemistry C, 2009Co-Authors: Jianshe Lian, Qing JiangAbstract:The size-dependences of the melting point, Debye Temperature, thermal expansion coefficient, and the specific heat of nanostructured materials have been modeled free of adjustable parameters. The melting point and Debye Temperature drop while the thermal expansion coefficient and specific heat rise when the grain size is decreased. Relative to nanoparticles, however, the variation of the above parameters of nanostructured material is weak, dominated by the ratio of the grain boundary energy to the surface energy. Our theoretical predictions agree fairly well with available experimental and computer simulation results for semiconductors and metals.
ştefan ţălu - One of the best experts on this subject based on the ideXlab platform.
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research on the influence of Temperature and pressure on volume enthalpy entropy Debye Temperature electrical resistivity thermal conductivity and thermal diffusivity of au with fcc structure
Social Science Research Network, 2021Co-Authors: Hoc Nguyen Quang, Dung Nguyen Trong, Van Cao Long, Hien Nguyen Duc, ştefan ţăluAbstract:The melting Temperature, the jumps of volume, enthalpy and entropy at the melting point, the isothermal compressibility, the thermal expansion coefficient, the heat capacity at constant volume, the Gruneisen parameter, the Debye Temperature, the electrical resistivity, the thermal conductivity and the thermal diffusivity for FCC defective and perfect metals are studied by combining the statistical moment method (SMM), the limiting condition of the absolute stability of the crystalline state, the Clapeyron-Clausius equation, the Debye model, the Gruneisen equation, the Wiedemann-Franz law and the Mott equation. Our numerical calculations of obtained theoretical results are carried out for Au under high Temperature and pressure. The SMM calculated melting curve of Au is in good agreement with experiments and other calculations. Our calculations for the jumps of volume, enthalpy and entropy, the thermal conductivity and the thermal diffusivity of Au predict and orient experimental results in the future.
Yan Wang - One of the best experts on this subject based on the ideXlab platform.
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coordination resolved local bond relaxation electron binding energy shift and Debye Temperature of ir solid skins
Applied Surface Science, 2014Co-Authors: Yan Wang, Yongli Huang, Xuexian Yang, Yezi Yang, Changqing SunAbstract:Abstract 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.
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raman spectroscopic determination of the length energy Debye Temperature and compressibility of the c c bond in carbon allotropes
Chemical Physics Letters, 2013Co-Authors: Yan Wang, X X Yang, J W Li, Z F Zhou, W T Zheng, J Z PengAbstract:Raman phonon relaxation dynamics in carbon allotropes including graphene, carbon nanotube, C60, carbon nanobud, graphite, and diamond has been formulated in terms of the bond order–length–strength (BOLS) correlation. The length and energy responses of the representative bond to the change of coordination environment, pressure, and Temperature determine intrinsically the Raman shifts. Reproduction of the measured results in quantitative information of the bond length, bond energy, mode cohesive energy, binding energy density, Debye Temperature, and the compressibility of the C–C bond in each phase without needing involvement of the phonon scattering resonant processes or the mode Gruneisen constants. 2013 Elsevier B.V. All rights reserved.
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raman spectroscopic determination of the length strength compressibility Debye Temperature elasticity and force constant of the c c bond in graphene
arXiv: Mesoscale and Nanoscale Physics, 2011Co-Authors: X X Yang, Yan Wang, Changqing Sun, Zhaofeng Zhou, Liwen Yang, Weitao ZhengAbstract:From the perspective of bond relaxation and vibration, we have reconciled the Raman shifts of graphene under the stimuli of the number-of-layer, uni-axial-strain, pressure, and Temperature in terms of the response of the length and strength of the representative bond of the entire specimen to the applied stimuli. Theoretical unification of the measurements clarifies that: (i) the opposite trends of Raman shifts due to number-of-layer reduction indicate that the G-peak shift is dominated by the vibration of a pair of atoms while the D- and the 2D-peak shifts involves z-neighbor of a specific atom; (ii) the tensile strain-induced phonon softening and phonon-band splitting arise from the asymmetric response of the C3v bond geometry to the C2v uni-axial bond elongation; (iii) the thermal-softening of the phonons originates from bond expansion and weakening; and (iv) the pressure- stiffening of the phonons results from bond compression and work hardening. Reproduction of the measurements has led to quantitative information about the referential frequencies from which the Raman frequencies shift, the length, energy, force constant, Debye Temperature, compressibility, elastic modulus of the C-C bond in graphene, which is of instrumental importance to the understanding of the unusual behavior of graphene.
