Showing papers on "Debye published in 1979"
TL;DR: In this paper, a model system composed of identical dielectric spheres ordered in a three-dimensional lattice is derived and the diffraction of uv or visible light is formulated, in which the large lattice constants and hence the low frequency of diffracted electromagnetic waves give rise to a Bragg reflection orders of magnitude stronger than that involved in the x-ray diffraction.
Abstract: For a model system composed of identical dielectric spheres ordered in a three-dimensional lattice, the secular equation of the energy band of photons is derived and the diffraction of uv or visible light is formulated. The model simulates void lattices in irradiated metals or ordered lattices in polystyrene latexes, in which the large lattice constants and hence the low frequency of the diffracted electromagnetic waves give rise to a Bragg reflection orders of magnitude stronger than that involved in the x-ray diffraction. The present formulation is an extension of the theory of Mie and Debye. Also, it is an extension of the Korringa-Kohn-Rostoker formalism for energy-band calculations to Maxwell's equations or to the vector Helmholtz equation. Although the present paper is restricted to developing a formulation, some characteristic aspects anticipated in low-energy photon diffraction are discussed in relation to low-energy electron diffraction.
308 citations
TL;DR: In this paper, the behavior of lattice models of quark confinement at high temperature was investigated and it was shown that at high temperatures, free gluons form a plasma which Debye screens the quarks.
Abstract: We consider the behavior of lattice models of quark confinement at high temperature. We find that confinement is strictly a low-temperature phenomenon. At high temperatures a transition to a plasma-like phase occurs. In this phase free gluons form a plasma which Debye screens the quarks.
306 citations
TL;DR: The observed dielectric response of most materials is seldom in accord with Debye behaviour, but has been found experimentally to exhibit a remarkable "universality".
Abstract: The observed dielectric response of most materials is seldom in accord with Debye behaviour, but has been found experimentally to exhibit a remarkable ‘universality.’ It is proposed that this universality is a consequence of some ubiquitous correlated states which exhibit an infrared (IR) divergent-like response to induced transitions of the polarising species.
292 citations
TL;DR: In this paper, the Debye theory of lattice vibrations has been examined in terms of the lattice vibrational spectra, and it is demonstrated that heat capacities of silicates show large deviations from the behavior expected from Debye theories, and that the observed thermodynamic deviations in minerals probably arise from four effects not included in Debye model: anisotropy of elastic parameters, dispersion of acoustic waves toward Brillouin zone boundaries, optic vibrations in excess of Debye spectrum at low frequencies, and optic vibrations at frequencies much greater than the debye cutoff frequency predicted
Abstract: This is the first of a series of five papers in which the thermodynamic properties of minerals are interpreted in terms of lattice vibrational spectra. In this paper, measured heat capacities for minerals are examined in terms of the Debye theory of lattice vibrations, and it is demonstrated that heat capacities of silicates show large deviations from the behavior expected from Debye theory. The underlying assumptions of Debye theory are critically reviewed, and it is shown that the observed thermodynamic deviations in minerals probably arise from four effects not included in the Debye model: anisotropy of elastic parameters, dispersion of acoustic waves toward Brillouin zone boundaries, optic vibrations in excess of the Debye spectrum at low frequencies, and optic vibrations at frequencies much greater than the Debye cutoff frequency predicted by acoustic measurements. Each of the four effects influences the heat capacity in a particular temperature range: anisotropy, dispersion and low-frequency optic vibrations are important at low temperatures (0°K to ∼100°K); high-frequency vibrations are important at higher temperatures. It is necessary to include all four effects in a generalized lattice vibrational model for minerals; such a model is developed in papers 2-5 of this series. The minerals included in this study are halite, periclase, brucite, corundum, spinel, quartz, cristobalite, silica glass, coesite, stishovite, rutile, albite, microcline, jadeite, diopside, enstatite, tremolite, talc, muscovite, forsterite, zircon, kyanite, andalusite, sillimanite, pyrope, grossular, andradite, spessartine, almandine and calcite.
249 citations
TL;DR: In this paper, a universal dielectric response was proposed for very low energy excitations in condensed matter, which exhibit an infrared-divergent-like response to transitions of the polarizing species induced by a time-varying electric field in the dielectrics.
Abstract: The dielectric response of condensed matter below microwave frequencies has been known to depart from the Debye behavior, sometimes to the point of being unrecognizable and yet the generally accepted interpretations of the departures have seldom deviated from the Debye philosophy of simple relaxation phenomena in noninteracting systems. It was recently recognized, from a synoptic view of the experimental data involving a wide range of materials, that there exists a remarkable universality of dielectric response behavior regardless of physical structure, types of bonding, chemical type, polarizing species, and geometrical configurations. This strongly suggests that there should exist a correspondingly universal mechanism of dielectric polarization in condensed matter. The present work proposes such a universal mechanism associated with the existence of some ubiquitous very-low-energy excitations in the system. These excitations exhibit an infrared-divergent-like response to transitions of the polarizing species induced by a time-varying electric field in the dielectric and give rise to the universal dielectric response.
176 citations
29 Jun 1979
TL;DR: In this paper, a universal dielectric response mechanism was proposed, associated with the existence of very low energy excitations in the system, which exhibit an infrared divergent-like response to transitions of the polarizing species induced by a time-varying electric field in the dielectrics.
Abstract: : The dielectric response of condensed matter below microwave frequencies has been known to depart from the Debye behavior, sometimes to the point of being unrecognizable and yet the generally accepted interpretations of the departures have seldom deviated from the Debye philosophy of simple relaxation phenomena in non-interacting systems. It was recently recognized, from a synoptic view of the experimental data involving a wide range of materials, that there exists a remarkable universality of dielectric response behavior regardless of physical structure types of bonding, chemical type, polarizing species and geometrical configurations. This strongly suggests that there should exist a correspondingly universal mechanism of dielectric polarization in condensed matter. The present work proposes such a universal mechanism associated with the existence of some ubiquitous very low energy excitations in the system. These excitations exhibit an infrared divergent-like response to transitions of the polarizing species induced by a time-varying electric field in the dielectric and give rise to the universal dielectric response. (Author)
173 citations
TL;DR: In this paper, the SCF and CI dipole moments for HCN, HNC, HNN, HCO+, HBO, HBF+, HCNH+ were computed and shown to be within 0.10 debye of their experimental values.
62 citations
TL;DR: In this paper, the Debye-Smoluchowski equation was used to model the reaction of isolated ion pairs in solution and an activation step was incorporated using a partially reflecting boundary condition.
Abstract: Reactions of isolated ion pairs in solution have been modelled using the Debye–Smoluchowski equation for diffusion and conduction An activation step was incorporated using a partially reflecting boundary condition The method of matched expansions and the Abelian theorem of Laplace transforms was used to give an approximate solution of the Debye–Smoluchowski equation Numerical integrations based on the finite‐difference method confirmed these approximate analytic formulas
57 citations
TL;DR: In this paper, a general framework about the influence of reactive particles on surface electronic structure and barrier formation at low coverages was deduced from experimental results obtained under thermodynamic equilibrium conditions on a suitable compound semiconductor model surface.
Abstract: A general framework about the influence of reactive particles on surface electronic structure and barrier formation at low coverages (ϑ?10−2) is deduced from experimental results obtained under thermodynamic equilibrium conditions on a suitable compound semiconductor ’’model surface.’’ Adsorption isotherms enable a rough classification of weak and strong electronic interactions into physisorption, chemisorption, and surface reaction steps, which depend on temperatures and partial pressures. (1) Covalent bonding of particles on ionic compound semiconductor surfaces, characterized by small partial charges formally attributed to the adsorption complex, may lead to extremely large dipole effects even at very low coverages [e.g.,dipole moments ≳ 15 Debye may formally be attributed to the adsorption complex ZnO (1010)/CO2,chem at ϑ<10−2]. Correspondingly, drastic changes are found in surface atom relaxation. Sticking coefficients are close to unity. (2) Ionic bonding, characterized by pronounced band bending, ...
51 citations
TL;DR: In this paper, a detailed analysis of the X-ray scattering intensity of alpha -AgI has been carried out by an anomalous scattering technique, and the two partial interference functions Sijdif(Q) for Ag-Ag and Ag-I pairs were estimated using the newly developed theoretical equations of the intensity.
Abstract: A detailed analysis of the X-ray scattering intensity of alpha -AgI has been carried out by an anomalous scattering technique. The two partial interference functions Sijdif(Q) for Ag-Ag and Ag-I pairs were estimated using the newly developed theoretical equations of the intensity. The partial distribution functions for I-I, Ag-I and Ag-Ag pairs in this work are consistent with the results obtained from molecular dynamics by Vashishta and Rahman (1978). The intensities of Debye lines were also explained satisfactorily in terms of pair distribution function for Ag-I pairs.
34 citations
TL;DR: In this article, the properties of one-dimensional gauge field theories at finite temperatures and densities were investigated and the massive Schwinger model in the presence of a uniform charge background was shown to form a Wigner crystal which Debye screens charged impurities.
Abstract: We consider the properties of one-dimensional gauge field theories at finite temperatures and densities. The massive Schwinger model in the presence of a uniform charge background is shown to form a Wigner crystal which Debye screens charged impurities. The two-species Schwinger model with oppositely charged fermions is studied at finite baryon density. This system does not undergo a phase transition as the density is increased, but becomes progressively more polarizable until at infinite density Debye screening occurs. Finally we consider the massive Schwinger model at nonzero temperature and show that Debye screening occurs at infinite temperature. We speculate that in three dimensions this last transition occurs at finite temperature.
TL;DR: In this article, it was shown that for any polar molecule having an electric dipole moment μ > 1.625 debye, the Born-Oppenheimer energy calculation must yield a positive electron affinity.
TL;DR: In this paper, a new electrostatic method for the equilibrium properties of non-primitive electrolyte solutions is proposed, based on the following key ideas: the microscopic electrostatic equation for the ionic-polar mixture is reduced by averaging to a coupled hierarchy of effective electrostatic equations which depend, respectively, on the coordinates of 0, 1, 2, 3, etc., molecules.
Abstract: A new electrostatic method for the equilibrium properties of nonprimitive electrolyte solutions is proposed. The theory is developed in detail for a 1‐1 symmetric electrolyte composed of equal radius rigid spheres with embedded charges and dipoles. The theory is based on the following key ideas. The microscopic electrostatic equation for the ionic–polar mixture is reduced by averaging to a coupled hierarchy of effective electrostatic equations which depend, respectively, on the coordinates of 0, 1, 2, 3, etc., molecules. The first member of the hierarchy, which determines the macroscopic electrostatics in the solution, involves a salt concentration dependent dielectric constant e and a generalized Debye inverse screening length κ. These constitutive parameters are determined self‐consistently from the solutions of the second set of hierarchy equations. These are rendered tractable by a mean field closure of the hierarchy which is tantamount to assuming the constitutive parameters of the solution when one ...
TL;DR: In this article, the Born-von Karman model of lattice dynamics of diamond structure has been extended to include up to 12th-neighbor interactions and the authors obtained very good fits to the experimental values of phonon dispersion curves and elastic constants.
Abstract: The Born-von Karman model of lattice dynamics of diamond structure has been extended to include up to 12th-neighbor interactions. Applications to Ge and Si using eighth-neighbor interactions have been carried out. We obtained very good fits to the experimental values of phonon dispersion curves and elastic constants. However, in agreement with the conclusions of Herman, a reasonable fit can only be obtained using at least up to fifth-neighbor interactions. The special significance of the fifth neighbor is attributed to its structure. With the fitted force constants, we have calculated the phonon density of states using the high-resolution Gilat-Raubenheimer method. The calculated Debye temperatures and specific heats compare well with the experimental values.
TL;DR: In this article, the internal and free energies of a two-dimensional one-component plasma model, in the high-temperature Debye approximation, are investigated, and a domain of validity for this model is discussed.
Abstract: The internal and free energies of a two-dimensional one-component plasma model, in the high-temperature Debye approximation, are reinvestigated, and a domain of validity for this model is discussed.
TL;DR: In this paper, the soft mode Raman spectra of ferroelectric Pb5Ge3O11 have been carefully measured as a function of temperature and the parameters of various models for the soft-mode spectral response for frequencies larger than 4 cm-1 were obtained.
Abstract: The soft mode Raman spectra of ferroelectric Pb5Ge3O11 have been carefully measured as a function of temperature. These new results were analyzed to obtain the parameters of various models for the soft mode spectral response for frequencies larger than 4 cm-1. The modes employed were: (i) a Debye relaxational function for the overdamped spectra; (ii) a classically damped harmonic oscillator at all temperatures and (iii) a model which allows for coupling between the soft mode and phonon density fluctuations. It is found that the low-frequency Raman spectra are well described by the damped harmonic oscillator model for 30K
TL;DR: In this article, an approach is developed to the problem of the electrical conductivity of non-degenerate, highly ionized, non-ideal plasma, where a linear response theory is used in computations.
Abstract: An approach is developed to the problem of the electrical conductivity of nondegenerate, highly ionized, nonideal plasma. A linear response theory is used in computations. The electron trajectories required for the computation are obtained by a molecular dynamics method. The difference between the real electron trajectory from the classical one is taken into account by changing the electron-ion interaction potential at small distances. Additionally, a correction factor is introduced into the expression which should be averaged. The trajectories are computed for a set of initial configurations of electrons and ions obtained by the Monte-Carlo method, and the results are averaged. An electrical conductivity computation has been performed at Debye numbers from 0.5 to 0.05.
TL;DR: In this article, the dipole transition moment with internuclear separation was found to be −6.0 + 2.3 r in the range 3.6 r, where r is the number of atoms in the D 1 Π-X 1 Σ + system.
TL;DR: In this paper, measurements made at temperatures of 197, 233, and 294°K of the absolute intensities and self-broadening coefficients for the vibration-rotation lines of the 12C16O2 molecule were reported.
Abstract: Measurements made at temperatures of 197, 233, and 294°K of the absolute intensities and self-broadening coefficients for the vibration-rotation lines of the 201III←000 band of the 12C16O2 molecule, are reported. From these measurements, values have been derived for the vibration-rotation interaction factor (FVR), the purely vibrational transition moment (|R(O)|), and the intensity (SBand). The results are: EVR(m) = 1+(2.2±0.7)×10−3 m+(5.6±1.6)×10×5m2, |R(0)| = (2.064±0.017)×10−3 debye, SBand = 21,329±69 cm−1 km−1 atm−1STP. The results for the self-broadening coefficients are presented in the text.
01 Feb 1979
TL;DR: In this article, a theory for in-plane atom-surface scattering has been developed based on classical mechanics, which features single and double binary collisions with surface atoms and describes the contributions of the different types of collisions to the angular and energy distributions of the scattered particles.
Abstract: A theory for in-plane atom-surface scattering has been developed based on classical mechanics. It features single and double binary collisions with surface atoms and describes the contributions of the different types of collisions to the angular and energy distributions of the scattered particles. The differences between a purely two-dimensional treatment and the three-dimensional treatment of the scattering problem are discussed. Since it is found that these differences can be quite large a method has been developed which makes it possible to correct a two-dimensional calculation for the contribution of three-dimensional effects without an undue increase in computer time. Parameters of the interaction potential as well as the angle of incidence are found to significantly influence this correction. The theory also accounts for the thermal motion of the surface atoms treating them as harmonic oscillators and assuming the density of phonan states D(ω) from Debye's theory.
TL;DR: In this paper, the shape of the electric dipole moment function of a pyramidal XY 3 molecule with a low barrier to inversion over a wide range of values for the inversion coordinate was determined.
TL;DR: In this paper, the rotational constants B O and C O, a complete set of quartic centrifugal distortion constants and several sextic distortion constants were determined giving a total dipole moment of μ = 1.76(5) debye.
TL;DR: In this paper, the existence of a Lifschitz singularity in the density of states at zero energy in some random lattice systems of noninteracting bosons and fermions in any numberv of dimensions was proved rigorously.
Abstract: We prove rigorously the existence of a Lifschitz singularity in the density of states at zero energy in some random lattice systems of noninteracting bosons and fermions in any numberv of dimensions. The basic tool is a simple modification of the method of Fukushima to yield the correct upper and lower bounds for allv. We also comment on the mathematical difference between the models treated and the system of phonons with mass disorder in the harmonic approximation, whose behavior is known to be of Debye form, not Lifschitz, at low temperatures.
TL;DR: The application of modern electron diffraction to the determination of vibrational potential parameters of diatomic molecules is demonstrated in this paper, where the vibrational power of a diatomic system is directly introduced into the Debye intensity equation through the density matrix.
TL;DR: In this article, it was shown that the near ultraviolet absorption band of Michler's ketone covers three electronic transitions, an intense one polarized perpendicular to the dipole moment and a weaker one at higher energy polarized parallel to the Dipole moment.
Abstract: It is shown that the near ultraviolet absorption band of Michler's ketone covers three electronic transitions. There are two ππ* transitions, an intense one polarized perpendicular to the dipole moment and a weaker one at higher energy polarized parallel to the dipole moment, and an nπ* transition polarized parallel to the dipole moment. For the ππ* transitions the change of dipole moment upon excitation has been determined as 5.8 ± 0.5 and 3 ± 1 Debye, respectively. Whereas the nπ* state appears to be the first excited singlet state in non-polar media, it becomes the third excited singlet state in ethanol. The change of the absorption spectrum with temperature is discussed.
TL;DR: In this article, a procedure for calculating the Debye potential corresponding to a stationary axisymmetric distribution of charges and currents in the Kerr metric is given, and the potential of a point charge on the symmetry axis and the value of the charge resulting from the accretion in the case of a charged current loop situated in the equatorial plane are determined.
Abstract: A procedure for calculating the Debye potential corresponding to a stationary axisymmetric distribution of charges and currents in the Kerr metric is given. The electromagnetic potential is derived by differentiation. The potential of a point charge on the symmetry axis and the value of the charge resulting from the accretion in the case of a charged current loop situated in the equatorial plane are determined with this formalism.
TL;DR: In this paper, a low-pressure shock tube was used to calibrate the probe voltage and current response in a supersonic continuum plasma, and the dependence of probe response on Debye ratio Rp/λD and various flow parameters was investigated.
Abstract: The calibration of electrostatic triple‐probe voltage and current response in a supersonic continuum plasma has been carried out using a low‐pressure shock tube. The electron temperature Te and charge number density Ne are compared to probe voltage and current response, respectively, for a useful range of plasma parameters (1≲Rp/λD≲10, 2≲M≲5, and 7<φ13<35, where Rp is the probe radius, λD is the Debye length, M is the shock Mach number, and φ13 is the nondimensional probe voltage). The dependence of probe response on Debye ratio Rp/λD and various flow parameters was investigated. The probe voltage response was found to depend significantly on the Debye ratio. Expressions for electron temperature determination by triple probe are presented.
Abstract: On the basis of Onsager's phenomenological equation of motion, the generalized form of susceptibility is derived. This includes the damped harmonic oscillator (DHO), Van Vleck-Weisskopf and Frohlich susceptibility (VWF) and Debye relaxational model as different limiting cases, and is equivalent to that obtained from the Bloch equation for the Ising model in a transverse field which are used in the pseudo-spin model for KDP-type crystals. Characteristics and mutual relations of susceptibilities are discussed with an emphasis on the difference between DHO and VWF. For a heavily damped mode, DHO becomes difficult to physically interpret since the eigenfrequency and the damping factor may lose their original meaning. In such cases, the only important parameter is the distance from the origin to the pole of χ(ω) in the complex ω-plane.
TL;DR: In this paper, the systematics of elementary atom-solid energy exchange processes are studied based on the generalized Langevin equation (GLE) classical trajectory method, where the solid dynamics is parameterized by two bulk properties, a Debye frequency ωD and a transverse to longitudinal sound velocity ratio Rs.
Abstract: Model studies of the systematics of elementary atom–solid energy exchange processes are presented. The studies are based on the generalized Langevin equation (GLE) classical trajectory method [S. A. Adelman and J. D. Doll, J. Chem. Phys. 64, 2375 (1976)] and on a full isotropic continuum elastic treatment of both bulk and surface solid atom velocity response functions ? (t). Within both bulk (BEM) and surface (SEM) elastic models, the solid dynamics is parameterized by two bulk properties, a Debye frequency ωD and a transverse to longitudinal sound velocity ratio Rs. The Debye model used in earlier GLE simulations is a specialization of the BEM, Rs=1.0, and thus does not include surface effects, e. g., Rayleigh waves, accounted for in the SEM. The main results of the trajectory studies are as follows: Gas–solid energy transfer efficiency within the BEM depends very sensitively on Rs (for fixed ωD). For physical Rs values ∼0.2–0.6, BEM energy transfer is often much larger than Debye energy transfer. SEM en...
TL;DR: In this paper, the exact solution of this scattering problem is investigated in detail after a generalized Debye's expansion is established, and the presence of the spherical layer is evident from the second term of this development.