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Showing papers on "Debye published in 1982"


Journal ArticleDOI
TL;DR: This model describes quantitatively the relative activities of those CDNP-lysine cytochromes c which are modified outside of the interaction domain and it allows correction of the activities of Those modified inside the domain, on the front surface of the molecule, for the change in dipole moment.

345 citations


Journal ArticleDOI
TL;DR: In this paper, it was shown that the probability of the atom tunneling transition from molecule to a radical depends essentially on the thermal inter-molecular vibrations, which diminish the tunneling length, increasing the transition probability substantially.

94 citations


Journal ArticleDOI
TL;DR: In this paper, the three-dimensional problem of a charged spherical particle immersed in an ionic solution is solved asymptotically, where the small parameter used is δ/a, where δ is the Debye screening distance and a the radius of the particle.
Abstract: The three‐dimensional problem of a charged spherical particle immersed in an ionic solution is solved asymptotically. The small parameter used is δ/a, where δ is the Debye screening distance and a the radius of the particle. The solutions to the Poisson–Boltzmann equation are obtained inside the double layer and outside the double layer. They are matched together asymptotically to obtain a solution whose error is of order δ2/a2 smaller than the expression kept. A uniform solution valid in all the regions is also obtained. Comparison with numerical solution to the problem, which is usually tedious, shows excellent agreement.

79 citations


Journal ArticleDOI
TL;DR: In this article, a measurement of the field and temperature dependences of the drifting velocity of single W atoms on the W(110) plane is reported, and the dependences are found to agree well with an earlier theoretical model.
Abstract: When an adsorbed atom is subjected to a driving force at a diffusion temperature, it will perform asymmetric random walks. The driving force can be produced by an applied nonuniform high electric field. We report here a measurement of the field and temperature dependences of the drifting velocity of single W atoms on the W(110) plane. The dependences are found to agree well with an earlier theoretical model. From these data, the surface-induced dipole moment and the effective polarizability of the W adatoms can also be derived; they are found to be 0.97 debye and 14.4 ${\mathrm{\AA{}}}^{3}$, respectively. These values agree within statistical errors with other existing experimental and theoretical data.

64 citations


Journal ArticleDOI
TL;DR: In this paper, the skeletal heat capacity of linear macromolecules is shown to be best represented by only two vibrations per chain atom, and the experimental heat capacities for these analyses were collected in the ATHAS data bank.
Abstract: Automatic computer programs are developed to calculate one- two-, and three-dimensional Debye functions. Prior tables of these functions are critically reviewed. Also, strategies are derived to calculate Debye temperatures from heat capacities. Both, simple three-dimensional Debye analyses and Tarasov analyses were carried out on 35 linear macromolecules. The experimental heat capacities for these analyses were collected in the ATHAS data bank. It is shown that the skeletal heat capacity of linear macromolecules is often best represented by only two vibrations per chain atom. For most of the all-carbon chain macromolecules the intramolecular skeletal heat capacity can be given by Cvs=D1[520 (28/MW)1/2] whereMW is the molecular mass andD1 represents the one-dimensional Debye function. Polyoxides show a higher intramolecular theta temperature, but a lower intermolecular theta temperature. Double bonds and phenylene groups in the chain increase the intramolecular theta temperature.

64 citations


Journal ArticleDOI
TL;DR: In this paper, a theory has been developed for cylindrical and spherical probes and other collectors in collisionless plasmas, in the limit where the ratio of Debye length to probe radius vanishes.
Abstract: A theory has been developed for cylindrical and spherical probes and other collectors in collisionless plasmas, in the limit where the ratio of Debye length to probe radius (the Debye number λD) vanishes. Results are presented for the case of equal electron and ion temperatures. On the scale of the probe radius, the distributions of potential and density in the presheath appear to have infinite slope at the probe surface. The dimensionless current–voltage characteristic is the same for the cylinder as for the sphere, within the limits of error of the numerical results, although no physical reason for this is evident. As the magnitude of probe potential (relative to space) increases, the current does not saturate abruptly but only asymptotically; its limiting value is about 45% larger than at space potential. Probe currents for small nonzero λD approach those for zero λD only very slowly, showing power‐law behavior as function of λD in the limit as λD → 0, with power‐law exponents less than unity, resulting in infinite limiting derivatives with respect to λD.

61 citations


Journal ArticleDOI
TL;DR: In this paper, a simple mechanical torque is applied to 108 C2v triatomics in a molecular dynamics computer simulation, and the effect of the torque on equilibrium autocorrelation functions is evaluated for vectors of interest to the analytical theory of molecular diffusion in anisotropic liquids.
Abstract: A simple mechanical torque is applied to 108 C2v triatomics in a molecular dynamics computer simulation. The effect of the torque on equilibrium autocorrelation functions is evaluated for vectors of interest to the analytical theory of molecular diffusion in anisotropic liquids. The results of the simulation do not, in general, support the conventional viewpoint based on Debye’s theory of rotational diffusion. In particular, the angular momentum acf becomes more oscillatory in the anisotropic liquid, which is not the case in theories of liquid anisotropy such as those of Benoit, Ullman, and others in the literature.

56 citations


Journal ArticleDOI
TL;DR: Dielectric constant and loss of the membrane-active peptide alamethicin in octanol/dioxane mixtures have been measured and it turns out that in this quite lipophilic medium most of the peptide material exists as a monomer particle that has approximate length and diameter of 35 and 13 A.

55 citations


Journal ArticleDOI
TL;DR: In this article, a modified version of the Warren-Averbach profile analysis was used to study the deformed state of Al. X-ray Debye profile measurement was performed on deformed, recovered and annealed samples of commercial pure Al. The results are in good agreement with those obtained by other authors, which prove the reliability and correctness of the method.
Abstract: The Warren–Averbach profile analysis was modified to study the deformed state of Al. The X-ray diffraction effect of dislocations locating on cell boundaries may be treated as `size broadening', while that of dislocations inside cells is `strain broadening', which may be treated with Wilkens's theory. X-ray Debye profile measurement was performed on deformed, recovered and annealed samples of commercial pure Al. Some information concerning the dislocation glide systems and distribution as well as the differences between the deformed and recovered state were given by the Debye profile analysis. The results are in good agreement with those obtained by other authors, which prove the reliability and correctness of the method.

49 citations


Journal ArticleDOI
P. Andonov1
TL;DR: In this paper, a structural analysis of amorphous, viscous and liquid selenium was performed using X-ray diffraction in the wave vector region 0 A and over a large range of temperature (78 to 683 K).
Abstract: In this work results are presented of various experiments involving the amorphous form of massive selenium, and a structural study performed by X-ray diffraction in the wave vector region 0 A and over a large range of temperature (78 to 683 K). At first, to suppress doubts which subsist in spite of several published reports concerning amorphous material, we examine in detail the dependences of the physical properties and the structural variations on applying a uniaxial compression at 293 K in the metastable form. Comparisons between deformed or non-deformed materials (D a-Se or ND a-Se) are made using measurements of density, longitudinal sound velocity, differential thermal analysis, small angle scattering and careful analysis of the structure factor J(K). The information gained on the structural evolution with temperature is discussed. The variation of Debye temperature, determined from measures of sound velocity between 78 K and 300 K, permits us to calculate the thermal attenuation. In amorphous selenium, the Debye hypotheses are not valid. A temperature variation has no influence on the structure of the amorphous phase. In the viscous phase a slow evolution is observed but only in the liquid phase does a real change of J(K) appear. A disordered chain model is retained to describe the structure of the molecule in amorphous, viscous and liquid selenium. The elementary triangle of the selenium lattice remains constant. The intramolecular deformation is due to a limited variation of the dihedral angle which is random in sign. The limits of variation are reduced weakly by a uniaxial compression and also by an increase of temperature but only for T>Tg; the deformed chains approximate to the hexagonal arrangement. The presence of prolate ellipsoidal voids included between the chains explains the difference in density between the crystallized hexagonal Se and the amorphous material. Finally several simulated models are compared with the experimental J(K) measured at different temperatures. The same uncertainty always remains in the description of the models and the explanation of experiments as a result of the impossibility of separating the two contributive intra and intermolecular disorders.

45 citations


Journal ArticleDOI
TL;DR: The calculated value of the dipole moment was found to be larger than the value of direct measurements, indicating that several alamethicin molecules are required to form a conducting pore and that their dipole moments are oriented parallel to each other.

Journal ArticleDOI
TL;DR: The specific heat of the ternary semiconducting compounds CuGaSe2, CuGaTe2, and CuInTe2 was determined experimentally in a temperature region within 2 and 30 K as discussed by the authors.
Abstract: The specific heat Cv of the ternary semiconducting compounds CuGaSe2, CuGaTe2, and CuInTe2 is determined experimentally in a temperature region within 2 and 30 K. From the results the Debye temperatures and standard entropies are calculated. By dividing Cv into a Debye and two Einstein contributions the approximate shape of the low frequency phonon modes is estimated. Die spezifische Warmekapazitat CV der ternaren halbleitenden Verbindungen CuGaSe2, CuGaTe2 und CuInTe2 wird experimentell in einem Temperaturbereich von 2 bis 30 K bestimmt. Aus den Mesergebnissen werden Debyetemperaturen und Standardentropien berechnet. Durch Aufteilen von Cv in einen Debyeteil und zwei Einsteinteile last sich der genaherte Verlauf der niedrigfrequenten Phononenmoden abschatzen.

Journal ArticleDOI
TL;DR: In this paper, the anomalous asymptotic behavior of the Debye integral far from focus that occurs in the vicinities of the axis of the focusing system and the boundary of the geometrical-optics shadow was studied.
Abstract: We study the anomalous asymptotic behavior of the Debye integral far from focus that occurs in the vicinities of the axis of the focusing system and the boundary of the geometrical-optics shadow. The first terms in the asymptotic power series of the far field valid on the axis, on the shadow boundary, in the shadow, and in the geometrical illuminated region off axis are obtained to show how they change discontinuously as the field point passes from one region to another. We obtain the second-order term in the asymptotic power series valid in the last-named region to show how it grows without limit as the field point approaches the axis or the shadow boundary. We then derive an approximation valid far from focus that remains continuous as the field point approaches the axis and the shadow boundary. This approximation agrees with the asymptotic power-series results where they are valid. The continuous approximation is applied to determine the sizes of the regions where the field does not approximate the geometrical-optics field.

Journal ArticleDOI
TL;DR: In this paper, the specific heat of NbSe 3 was measured between 0.05 K and 6.5 K and the electronic linear contribution γT with γ = 24.5 erg/g.

Journal ArticleDOI
TL;DR: In this paper, the presence of hydrogen in Nb containing O and N interstitial impurities gives rise to a relaxation process at liquid helium temperature, studied by exciting two vibration modes of the specimen (20 and 75 kHz).


Journal ArticleDOI
TL;DR: In this article, an analytical expression for the X-ray Debye temperature (θM) of a hexagonal crystal in terms of the elastic constants was derived and used to calculate θM for hexagonal crystals of 41 elements and compounds.
Abstract: With the Debye continuum model an analytical expression is derived for the X-ray Debye temperature (θM) of a hexagonal crystal in terms of the elastic constants and this expression is used to calculate θM for hexagonal crystals of 41 elements and compounds. Calculated results by numerical integration are also presented for the X-ray Debye temperature perpendicular to the hexad axis, θ⊥, and that parallel to it, θ||. The calculated results are compared with experimental values, wherever data are available. A correction factor for the effect of dispersion is determined from the experimental data.

Journal ArticleDOI
TL;DR: In this paper, the Debye limit is applied to a suitable superposition of singular solutions of the linear two-component reaction-diffusion equations in three dimensions, leading to helical and twisted toroidal scroll waves of constant concentration.
Abstract: Applying the Debye limit to a suitable superposition of singular solutions of the linear two-component reaction-diffusion equations in three dimensions leads to helical and twisted toroidal scroll waves of constant concentration. An integral representation of the solutions of the Helmholtz equation in toroidal coordinates establishes a connection between helical and toroidal waves.

Journal ArticleDOI
TL;DR: In this paper, the rotational dependence of the dipole moment first derivatives is used in determining the signs of the first derivatives, which the absolute values are obtained from the infrared band intensity studies.

Journal ArticleDOI
TL;DR: In this article, generalised diffusion processes are discussed using the theory of stochastic processes and several elementary results for the survival probability of a pair of particles with an arbitrary potential.

Journal ArticleDOI
TL;DR: In this article, the authors examine the likely magnitude of such a photodielectric effect and consider the thermodynamic, kinetic and photochemical factors likely to limit the efficiency of a solar conversion device employing it.
Abstract: In principle the absorption of light can cause an increase in the permittivity of a dielectric material, and hence in the capacity of a capacitor containing the material. Periodic interruption of the light can therefore cause the capacity to fluctuate, and, in the presence of an applied field, act as a generator of alternating current. In this paper we examine the likely magnitude of such a photodielectric effect and consider the thermodynamic, kinetic and photochemical factors likely to limit the efficiency of a solar conversion device employing it.We conclude that a photodielectric device is attractive in principle because it circumvents some of the restraints encountered with conventional photovoltaic systems. However, for reasonable efficiency severe difficulties would have to be overcome. Chiefly these are that (1) the dipole moment of a molecule in the excited state of the dielectric material should exceed that of the ground state by more than 10 debye, (2) the excited state should have a long half-life and (3) the applied field strength should approach the breakdown value of known dielectrics.

Journal ArticleDOI
TL;DR: In this paper, the Bethe Ansatz approach is applied to calculate the specific heat of the massive-thirring model with a Debye cutoff, and the results are close to that of the classical sine-Gordon system.

Journal ArticleDOI
TL;DR: In this paper, a new scaling length, whose use is complementary to that of extrinsic Debye length is proposed for cases where fixed charge is dominant, was proposed for distance normalization in cases where mobile charges are dominant.
Abstract: Intrinsic and extrinsic Debye lengths have been extensively used in device modeling work. Recently Jindal and Warner [4], using extrinsic Debye length, have developed a unified solution applicable to all step junctions. They have further extended it to include the semiconductor surface problem [5]. As a result of these general analyses, the role of extrinsic Debye length in distance normalization in cases where mobile charges are dominant has been more clearly understood. A new scaling length, whose use is complementary to that of extrinsic Debye length is proposed for cases where fixed charge is dominant.

Journal ArticleDOI
TL;DR: In this article, the effects of rotational-vibrational coupling were discussed and the most reliable results were obtained from the ν4 vibration and indicated that reorientational relaxation occurs close to the Debye limit.
Abstract: Reorientational correlation functions have been obtained from the analysis of the totally symmetric vibrations ν4, ν5 and ν2 of liquid cyclohexane. For the interpretation of the data, the Kubo line shape theory was assumed to be valid. The most reliable results were obtained from the ν4 vibration and indicated that reorientational relaxation occurs close to the Debye limit of rotational diffusion. The data are compared with NMR results given in the literature. The effects of rotational-vibrational coupling are discussed.

Journal ArticleDOI
TL;DR: A physically based model for the ionic currents associated with the neural membrane is further developed to predict the spatial dependence as well as the time dependence of the electrical and chemical potentials by solution in three dimensions of the associated nonlinear equations as discussed by the authors.

Journal ArticleDOI
TL;DR: In this article, the rotational energy levels with normalized Boltzmann factors larger than 5×10−8 at 300°K were calculated, and probabilities of all possible electric dipole transitions among these states, 2277 lines, were calculated using the eigenfunctions thus obtained, and the permanent dipole moment of 1.8546 Debye.
Abstract: Using the values of the rotational molecular parameters (including cencrifugal distortion terms) of the H216O molecule, which can explain 12 observed transitions below 800 GHz, all rotational energy levels with normalized Boltzmann factors larger than 5×10−8 at 300°K are calculated. Probabilities of all possible electric dipole transitions among these states, 2277 lines, are calculated using the eigenfunctions thus obtained, and the permanent electric dipole moment of 1.8546 Debye. Assuming the single and full Lorentzian line forms, we calculated the absorption coefficient for millimeter to submillimeter region. Our result, using the single term Lorentzian line form, agrees quite well with experiment for 1 Torr of water vapor in 760 Torr air at 300°K.

Journal ArticleDOI
TL;DR: In this paper, the normal modes of vibrations in some transition metal oxides have been studied by means of a 7-parameter bond-bending force model (BBFM), recently developed for phonons in highly ionic crystals with NaCl structure.
Abstract: The normal modes of vibrations in some transition metal oxides have been studied by means of a 7-parameter bond-bending force model (BBFM), recently developed for phonons in highly ionic crystals with NaCl structure. The phonon dispersion relations along three highest symmetry directions for MnO, CoO, and NiO are found to give a satisfactory fit to the neutron scattering measurements. The complete phonon spectra in the first Brillouin zone have also been used to compute the phonon density of states and to derive the temperature dependence of the Debye characteristic temperature (θ D ). The derived θ D - T curves also give a fairly good agreement with the available experimental data.

Journal ArticleDOI
TL;DR: In this article, the peculiarities of the influence of Debye parameters' variations on the characteristics of the microwave radiation field of water solutions are examined, and approximate expressions for the dependence of brighness temperature versus physical temperature and salinity of water are obtained for different wavelengths.
Abstract: The peculiarities of the influence of Debye parameters' variations on the characteristics of the microwave radiation field of water solutions are examined. Examples of these parameters and their variation according to the data of different authors are presented. Approximate expressions for the dependence of brighness temperature versus physical temperature and salinity of water are obtained for different wavelengths.

Journal ArticleDOI
TL;DR: In this article, the Debye-Waller factors of highly anharmonic double-minimum and flat-bottomed one-particle potentials were investigated in the presence or absence of a potential barrier at the midpoint.
Abstract: Analytical expressions are obtained for the Debye-Waller factors of highly anharmonic double-minimum and flat-bottomed one-particle potential which differ only in the presence or absence of a potential barrier at the mid-point. A lack of sensitivity in the Debye-Waller factors to the presence of the potential barrier is demonstrated for potentials with parameters modelling the hydrogen atom in the KH2PO4-type ferroelectrics at room temperature. The analysis indicates that a series of measurements with decreasing temperature may be necessary for a double minimum in the potential to be resolvable for these systems. The Debye-Waller factors investigated here show an anomalous temperature dependence in certain regions of reciprocal space, where they produce constant or even increasing integrated intensities of Bragg diffraction peaks with increase in temperature. Comparisons are made with the Debye-Waller factors for a disorder model, based on a one-particle probability density constructed from two displaced Gaussian distributions. This model is unable to reproduce the anomalous temperature dependence predicted by the anharmonic potentials.

Journal ArticleDOI
TL;DR: In this article, a dipole moment of the transition state is estimated to be 8.5±0.5 Debye, which is larger than either the complex (assumed as 1 Debye) or that of the cycloadduct (6±1 Debye).
Abstract: Experimental evaluation was made of rate constants for foward and backward steps of 1,4-cycloaddition between TCNE and α-methylstyrene and of constants for their complex formations in 1,2-dichloroethane, dichloromethane, chloroform, and carbon tetrachloride at a few temperatures around 25 °C. Kirkwood’s dipole model for solvation is applied to analyzing kinetic data obtained. The dipole moment of the transition state is estimated to be 8.5±0.5 Debye, which is larger than either that of the complex (assumed as 1 Debye) or that of the cycloadduct (6±1 Debye). Major cause for the high dipole moment of the transition state is breakdown of the high molecular symmetry of TCNE and minor one is a certain contribution of a zwitterionic structure. The activation entropy for the cycloreversion is negative and in the range of −21 to −48 J K−1 mol−1, corresponding to the high polarity of the transition state.