Showing papers on "Debye published in 1984"
TL;DR: A detailed analysis of the pulsed bias techniques used to determine the capture kinetics of free carriers by deep traps in Schottky diodes or asymmetric bipolar junctions is presented in this article.
Abstract: A detailed analysis of the pulsed bias techniques used to determine the capture kinetics of free carriers by deep traps in Schottky diodes or asymmetric bipolar junctions is presented. Both exact simulations, involving an exact integration of Poisson’s equation and a self‐consistent treatment in the case of large deep trap concentrations and simple analytical approximations are given. The usual depletion approximation for the distribution of free carriers in the Debye tail is demonstrated to yield erroneous results in some occasions and it is shown how to deal simply with the exact distribution. A novel experimental technique is proposed to rigorously extract the exponential capture kinetics in the neutral semiconductor, from the total capture kinetics, getting rid of the capture in the Debye tail; it is also shown how it is possible to obtain a correct estimation of the capture rate from the capture in the Debye tail, when the direct determination by the above mentioned method is impossible.
158 citations
144 citations
TL;DR: In this paper, a diagrammatic analysis of the thermal width and shift of the zero-phonon line was performed for two model phonon densities of states: the Debye model for acoustic phonons, and a sharply peaked density of states appropriate for optical phonons.
Abstract: We continue the discussion of the nonperturbative theory of zero‐phonon impurity lines in crystals formulated by Osad’ko and more recently by us. In that paper, a diagrammatic analysis was undertaken which led to analytic results for the thermal width and shift of the zero‐phonon line. Here we evaluate these results for two model phonon densities of states: the Debye model for acoustic phonons, and a sharply peaked density of states appropriate for optical phonons. For Debye phonons we find that at low temperatures the standard (perturbative) theory of optical dephasing is qualitatively correct, but at high temperatures it becomes very inaccurate. Moreover, if one of the excited state phonon frequencies tends to zero (a soft mode), then perturbation theory breaks down completely. For optical phonons our results give an Arrhenius temperature dependence for the linewidth and place an upper bound on the value of the preexponential. In paper II of this series we will discuss dephasing by pseudo‐local phonons,...
72 citations
TL;DR: In this paper, the rotational and vibrational energy levels of the isomers CCN+ and CNC+ have been determined in the following way: a large number of points in the minimum region of the 1Σ+ electronic ground state surfaces of the two ions have been computed by single reference state complete single and double excitations configuration interaction (CI-SD) calculations using canonical SCF orbitals as a molecular orbital basis.
61 citations
TL;DR: In this article, the theory of nonlocal elastic solids is introduced and applied to the discussion of Debye screening of an electron in an elastic solid with defect and dispersion of optical and piezoelectric waves.
Abstract: Constitutive equations are derived for nonlinear and linear, nonlocal piezoelectric elastic solids. Restrictions arising from the second law of thermodynamics are determined. The theory of nonlocal em elastic solids is introduced and applied to the discussion of Debye screening of an electron in an elastic solid with defect and dispersion of optical and piezoelectric waves.
53 citations
TL;DR: In this paper, the authors examined the inherent packing structures of a simple model substance which freezes into a bcc crystal and found that the resulting collections of inherent structures possess quenched pair correlation functions that are nearly independent of the initial state temperature, provided the latter correspond to fluid states.
Abstract: The collection of potential energy minima in a condensed phase determines its inherent packing structures. We have examined these inherent structures for a simple model substance which (like Na) freezes into a bcc crystal. Molecular dynamics trajectories at several different temperatures were periodically sampled, and each of the configurations was ‘‘quenched’’ by a steepest‐descent construction into a nearby potential energy minimum. The resulting collections of inherent structures possess quenched pair correlation functions that are nearly independent of the initial‐state temperature, provided the latter correspond to fluid states. Attempts to reconstitute the equilibrium pair correlation functions by thermally broadening the quenched versions, using harmonic Einstein or Debye vibrational approximations, were clear failures. Evidently the true broadening phenomenon entails substantial anharmonicity.
45 citations
42 citations
01 Mar 1984
TL;DR: In this paper, a new mechanism for collective polarization dynamics in a polar liquid is introduced, which couples hydrodynamic motions of the liquid to dielectric relaxation by both rotational and translational diffusion of polar molecules.
Abstract: We introduce a new mechanism for collective polarization dynamics in a polar liquid. This continuum model couples hydrodynamic motions of the liquid to dielectric relaxation by both rotational and translational diffusion of polar molecules. As an application of our theory we calculate the dielectric friction on an ion in a solvent that relaxes only by the translational diffusion mechanism. The result is quite different from dielectric friction dominated by rotational (Debye) relaxation.
29 citations
TL;DR: In this paper, a random mixture of a ferroelectric and an antiferroelectric, Rb 1-x (NH 4 ) x H 2 PO 4, has been carried out.
Abstract: X-ray study on a random mixture of a ferroelectric and an antiferroelectric, Rb 1- x (NH 4 ) x H 2 PO 4 , has been carried out. The glassy phase (dipole-glass phase) is found to be tetragonal, although the deviation of a lattice parameter from the Debye approximation is seen at low temperatures. The intensity of the X-ray diffuse scattering increases with decreasing temperature in the glassy phase. The results suggest a freezing of the short range order or the local polarization in the glassy phase.
25 citations
TL;DR: In this article, the authors used the Debye approximation of the second-order Doppler shift to separate the isomer shift from the measured center-of-gravity shifts of the spectra.
Abstract: The authors report on 57Fe Mossbauer isomer shift measurements of Fe0.64Ni0.36, Fe0.68Ni0.32 and Fe0.60Ni0.20 FCC Fe alloys in the temperature range from 13 to 1010K. The Weiss 2 gamma -states model and a simple 'volume model' have been fitted to the experimental data in order to explain the observed temperature dependence of the isomer shift. To separate the isomer shift from the measured centre-of-gravity shifts of the spectra, the authors used the Debye approximation of the second-order Doppler shift. The Debye temperatures were assumed to be dependent on temperature.
24 citations
TL;DR: In this article, an analysis of sub-Doppler laser-Stark spectra of 14NH3 obtained using a CO laser and an intracavity Stark cell is given.
TL;DR: In this article, an electric field induced predissociation of the B 2 Π0 u + state of molecular iodine to the unbound 1g state was studied by the observation of laser induced fluorescence of iodine.
TL;DR: In this paper, the Pippard-Ziman condition on the electron-phonon interaction was used to model the electron mean free path in amorphous metals, and the results were consistent with the observed rho vs. temperature T in low resistivity glassy metals.
Abstract: : Electrical transport in amorphous metals is analyzed in the context of the Baym-Faber-Ziman theory. The theory is generalized to incorporate electron mean free path effects through the Pippard-Ziman condition on the electron-phonon interaction. A variety of model t-matrices are considered. The geometrical structure factors are modeled by Percus-Yevick hard sphere forms and a single branch Debye phonon spectrum is assumed. Detailed results for electrical resistivity rho vs. temperature T and the TCR are presented for extensive ranges of 2kF/kp and electron mean free path. The results, incorporating the Pippard-Ziman condition, are consistent with the observed rho vs. T in low resistivity glassy metals. However, although inclusion of the Pippard-Ziman condition dramatically improves agreement with the data, quantitative agreement is not obtained in high resistivity amorphous metals.
TL;DR: In this article, a classical charge symmetric system with an external charge distribution was studied in three dimensions in the limit that the plasma parameter ǫ→ zero, and it was shown that if q is scaled appropriately then the correlation functions converge pointwise to those of an ideal gas in the external mean field.
Abstract: We study a classical charge symmetric system with an external charge distributionq in three dimensions in the limit that the plasma parameter ɛ→ zero. We prove that ifq is scaled appropriately then the correlation functions converge pointwise to those of an ideal gas in the external mean fieldΨ(x) where Ψ is given by-ΔΨ+ 2z sinh(βΨ) =q This is the mean field equation of Debye and Huckel. The proof uses the sine-Gordon transformation, the Mayer expansion, and a correlation inequality.
TL;DR: In this paper, two absorption bands due to the motion of the center of mass of the off-center OH ion in NaCl crystal were observed at 1.85 and 1.56 cm -1 and assigned to the transitions between A 1g and T 1u states and between T 1 u and E g states, respectively.
Abstract: The absorption spectrum and its temperature dependence of the off-center OH - ion in NaCl crystal has been observed in the millimeter wave region from 1.1 to 2.5 cm -1 ( λ=4 to 9 mm). Two absorption bands due to the motion of the center of mass of the OH - ion have been observed at 1.85 and 1.56 cm -1 and are assigned to the transitions between A 1g and T 1u states and between T 1u and E g states, respectively. The transition dipole moments of the former and the latter transitions are estimated as 1.6 and 3.7 debye. The ratio of the two transition energies is 1.19 and this value is different from the ratio of 2 predicted by the tight well tunneling model. The energy levels are explained well by the LCAO-MO calculation based on a three dimentional adiabatic potential proposed by Gomez, Bowen and Krumhansl.
TL;DR: In this paper, the exact intensity formula of the h-line profile from small crystallites has been obtained as the orientational average of the diffraction intensity of the H plane given by Ino & Minami.
Abstract: The exact intensity formula of the h-line profile from small crystallites has been obtained as the orientational average of the diffraction intensity of the h plane given by Ino & Minami [Acta Cryst. (1979), A35, 163-170]. While the formula is expressed as a triple integral including a sine Fourier integral, it can be expressed asymptotically with respect to the crystal size according to the theorem of asymptotic expansion of a Fourier integral. Hence the profile can be estimated by the sum of terms of single-integral type. The first term is of the same type as Wilson's formula but it has been shown that second and third terms improve considerably the accuracy of the asymptotic estimation especially for a very small crystal. The h-line profile can be successfully calculated for quite a small crystal of any shape and any crystal system by the asymptotic formula, which can be computed as easily as Wilson's formula.
TL;DR: In this article, the microwave spectrum of diazabicyclooctene (C 6 H 10 N 2 ) has been used to determine the ground vibrational state rotational constants.
TL;DR: In this paper, the temperature dependence of the mean square displacement for Al is quantitatively calculated from first principles, and the Debye temperature at higher and lower temperatures is also estimated using Debye's model.
Abstract: The temperature dependence of the mean-square displacement for Al is quantitatively calculated from first principles. The Debye temperature at higher and lower temperatures is also estimated using Debye's model. Then, using the volume dependence of the mean-square displacement, the pressure effect on the melting temperature of Al is studied by Lindeman's melting law, and the melting curve obtained increases as function of the compressed volume.
TL;DR: In this paper, the incoherent inelastic neutron scattering spectrum of HCCo3(CO)9 has been obtained in order to test some present methods of calculating band intensities for polycrystalline samples.
Abstract: The incoherent inelastic neutron scattering (IINS) spectrum of HCCo3(CO)9 has been obtained in order to test some present methods of calculating band intensities for polycrystalline samples. The fundamental and first overtones of the carbon-hydrogen bending mode were observed at 860 and 1712 cm-1 respectively. The C-H stretching mode was observed at 3041 cm-1 and this is the first report of the observation of such a mode in which there is no possibility of confusion with overtone and combination bands.
TL;DR: In this article, the structure factor of an amorphous material contains both elastic and inelastic contributions and the localisation in reciprocal space and the relative weights of the elastic and elastic contributions are studied.
TL;DR: In this article, the velocity and attenuation of hypersound waves propagating along [100], [110], and [111] axis in gadolinium gallium garnet and along [ 100] and [ 111]axis in yttrium aluminum garnet are measured at frequencies 0.714 to 2.106 GHz at the room temperature.
Abstract: The velocity and the attenuation of hypersound waves propagating along [100], [110], and [111] axis in gadolinium gallium garnet and along [100] and [111] axis in yttrium aluminum garnet are measured at frequencies 0.714 to 2.106 GHz at the room temperature. The second order elastic constants, Debye temperatures, and the Gruneisen constants are calculated from this results.
TL;DR: In this paper, the mean square dipole moments of poly(dimethylsiloxane) (PDMS) linear chains were calculated for cyclohexane and benzene at 30°C.
TL;DR: In this paper, the integrated intensities of Bragg reflections are measured for AgCl and AgBr at room temperature using an x-ray powder diffractometer, and the Debye-Waller factors and Debye temperatures are evaluated.
Abstract: The integrated intensities of Bragg reflections are measured for AgCl and AgBr at room temperature using an x-ray powder diffractometer. The Debye-Waller factors and Debye temperatures are evaluated.
TL;DR: In this paper, the effects of neon and argon impurities in dense, hot hydrogen plasmas (T approximately 200 eV, Ne approximately 1024 cm-3) were investigated using the temperature-dependent density functional method.
Abstract: Non-linear screening effects of neon and argon impurities in dense, hot hydrogen plasmas (T approximately 200 eV, Ne approximately 1024 cm-3) are investigated using the temperature-dependent density functional method. The results are compared with corresponding linear screening (Debye-Huckel and RPA) calculations. The drastic differences in the results reveal the complete inadequacy of linear response theories (Debye and RPA screening) in these ranges of densities and temperatures. The usefulness of such non-linear self-consistent screening models is discussed.
Journal Article•
TL;DR: The Debye potential formalism is a simple and elegant method of representing and analyzing radiation fields in classical electromagnetism as mentioned in this paper, but there are a number of unanswered questions about the formalism.
Abstract: The Debye potential formalism is a simple and elegant method of representing and analyzing radiation fields in classical electromagnetism. Despite this, there are a number of unanswered questions about the formalism. One of these, the transformation properties of the potentials under Lorentz boosts, is dealt with in this article.
TL;DR: In this article, the influence of the interaction of two equivalent internal rotors on the dielectric dispersion was investigated, and a drastic deviation of the Cole-Cole plot from the Debye semicircle was found when the two rotors, each carrying a permanent dipole, interact so as to increase the total dipole moment.
TL;DR: In this article, microwave measurements of the normal isotopic species of 3-cyanocyclopropene have given the following ground vibrational state rotational constants: A = 19876.036 ± 0.006, B = 3533.743 ± 0., and C = 3417.839 ± 0,001 MHz.