Showing papers in "Canadian Journal of Physics in 1989"
TL;DR: In this paper, the historical postulates for the point mass were shown to be satisfied by an infinity of space-times, differing as to the limiting acceleration of a radially approaching test particle.
Abstract: The historical postulates for the point mass are shown to be satisfied by an infinity of space–times, differing as to the limiting acceleration of a radially approaching test particle. Taking this ...
83 citations
TL;DR: Water vapor Fourier transform spectra were analyzed between 9500 and 11500 cm −1 resolution in this paper, with an average uncertainty of about 15% for the first decad of H 2 16 O.
Abstract: Water vapor Fourier-transform spectra (0015 cm −1 resolution) were analyzed between 9500 and 11500 cm −1 Accurate values of 557 rotational energy levels, belonging to the interacting vibrational states (041), (220), (121), (022), (300), (201), (102), and (003) of the first decad of H 2 16 O, were determined Moreover, 718 line intensities were accurately measured (7% uncertainty) To increase the number of experimental intensities (needed for atmospheric applications), a faster method, using the measured line depths, has made it possible to obtain 1695 additional intensities, with an average uncertainty of about 15%
71 citations
TL;DR: Highly crystalline LixMoS2 was synthesized, and the lithium content was electrochemically varied between x'~'0 and x'´~'1'.
Abstract: Highly crystalline LixMoS2 was synthesized, and the lithium content was electrochemically varied between x ~ 0 and x ~ 1. There were five different phases each with a different lithium content. The...
43 citations
TL;DR: In this paper, the laser-induced fluorescence of the and transitions of Na2 were analyzed using high-resolution Fourier transform spectroscopy, using high resolution Fourier Transform Spectroscopy (FTS).
Abstract: The laser-induced fluorescence of the and transitions of Na2 are analysed, using high resolution Fourier transform spectroscopy. Fixed-frequency ion-laser lines (4880 and 4765 A (1 A = 10−10 m) from Ar+ and 6471 and 4762 A from Kr+) together with laser frequencies from a ring dye laser, using rhodamine 6 G with λ = 5781.22 and 5796.80 A, were used to excite Na dimer in the gas phase. Twenty-eight series of and systems have been assigned and analysed, and the strong transitions are accompanied by numerous rotational relaxation lines. Molecular constants of the state were calculated with high precision from simultaneous least-squares fits to 1410 lines assigned to the A–X and B–X systems. These constants have been used to determine the Rydberg–Klein–Rees potential curve of the X ground state for vibrational levels up to ν = 62.
35 citations
TL;DR: In this article, the authors present observational evidence for the simultaneous occurrence of an ionization ledge in the topside and a counterelectrojet in the E-region altitudes of the equatorial ionosphere.
Abstract: In this paper we present observational evidence for the simultaneous occurrence of an ionization ledge in the topside and a counterelectrojet in the E-region altitudes of the equatorial ionosphere. The following morphological features of the ionization ledge are found to be the same as those of the counterelectrojet phenomenon: namely, occurrence on a sequence of days in succession, preferential occurrence during a solar minimum period as compared with a solar maximum period, occurrence in a limited longitudinal belt, and lunar control of the occurrence as revealed by our data.There is also a high degree of correlation on both magnetically quiet and magnetically disturbed days between the ionization ledge and the counterelectrojet. Our study brings out a close coupling in the occurrence and morphological features of the two low-latitude phenomena, even though they are widely separated in altitude. The implications of such a correlation, with special reference to the understanding of the dynamical coupling...
33 citations
TL;DR: In this paper, the spectrum of CH4 obtained in CH4 plus N2 mixtures at a temperature of 77 K has been recorded with a spectral resolution of 0.14 cm−1 in the region 3800 to 9100cm−1.
Abstract: The spectrum of CH4 obtained in CH4 plus N2 mixtures at a temperature of 77 K has been recorded with a spectral resolution of 0.14 cm−1 in the region 3800 to 9100 cm−1. The experiments were performed with long paths (66 or 88 m) in a cooled absorption cell using a Fourier-transform spectrometer. Data are presented here at low and medium resolution, and examples of some spectral regions are also shown at high resolution. The complete results are available from the author in an Appendix. Comparisons are made with previous model calculations of CH4 absorption, and with the observed spectrum of Neptune's satellite, Triton. The results should be useful for the interpretation of the spectra of Triton, Titan, and Pluto. They will also be of value for testing model calculations of low-temperature CH4 absorption, which, thus verified, can be used with greater confidence to analyze observations of Jupiter, Saturn Uranus, and Neptune.
31 citations
TL;DR: In this paper, the authors derived a variational expression for the real part of the Kramers-Kronig relation for a general exchange-correlation (XC) action functional.
Abstract: Within the framework of the time-dependent spin density functional formalism, we study the dynamical spin susceptibility of a general system of interacting electrons in the presence of a static external scalar potential. Based on the stationary property of the action functional, a variational expression for the real part of is derived: . The result is valid for a general exchange-correlation (XC) action functional. In particular, the XC factor 1(q,ω) is manifestly dependent on q and ω. The imaginary part Im is then determined through the Kramers–Kronig relation. Practical approximations for the required XC kernel are also discussed
30 citations
TL;DR: In this paper, the formation of a highly stable and well-ordered pure icosahedral (i) phase in Al80TMl20−xTM2x(TM1 = V, Cr; TM2 = Fe, Co).
Abstract: Through an X-ray diffraction and thermal analysis investigation of melt spun Al – transition metal (Al–TM) alloys, we report the formation of a highly stable and well-ordered pure icosahedral (i) phase in Al80TMl20−xTM2x(TM1 = V, Cr; TM2 = Fe, Co). The superior i-phase formation over that in the binary Al–TM alloys is interpreted in terms of the distribution of TM sites known to exist in this phase. A comparison of the i-phase formation ranges indicates the presence of two distinct classes of TM sites and a strong interaction between adjacent TM sites.
30 citations
TL;DR: In this article, high-resolution Fourier transform spectrometry was used to detect weak perturbations in the C3Πu state of the 14N2 molecule and the molecular constants for the ν ǫ = 0 level of the state were computed.
Abstract: The C3Πu – B3Πg System of the 14N2 molecule has been recorded by high-resolution Fourier transform spectrometry between 20 000 and 32 000 cm−1. Four bands (0–0, 0–1, 0–2, 0–3) were analyzed initially. The whole set of wavenumbers has been fitted using a nonlinear procedure. The molecular constants for the ν = 0 level of the C3Πu state have been computed. Weak perturbations were detected unambiguously.
26 citations
TL;DR: In this paper, the effect of substrate orientation on optical properties of nonpseudomorphic InxGa1-xAs epitaxial layers grown by metal organic vapour-phase epitaxy has been investigated in two series of samples.
Abstract: The effect of substrate orientation on the optical properties of nonpseudomorphic InxGa1–xAs epitaxial layers grown by metal organic vapour-phase epitaxy has been investigated in two series of samples. Series (a) samples were grown on GaAs substrates cut 2° off (001) towards , and those of series (b) were grown on GaAs substrates cut exactly on (001). The low-temperature photoluminescence spectra of the two series of samples differ drastically. Those of the (a) series are characteristic of highly uniform, fully relaxed ternary layers and are used to determine the composition dependence of the alloy band gap and of the carbon acceptor binding energy. In contrast, those of the (b) series are dominated by an intense, low-energy emission, which is attributed to exciton recombinations in small regions of small band gap. The reduction of the band gap is tentatively assigned to the presence of In-rich regions created by the large strain fields present along dislocations. The density of dislocations is much large...
22 citations
Abstract: A variable-energy positron beam was utilized to study the interface action of hydrogen with Si(111) covered by an ultrahigh-vacuum thermally grown oxide of 2–3 nm thickness. It was observed that positrons implanted at shallow depth (<100 nm) after diffusion are trapped either at the interface between the oxide and the Si or in the oxide. The positron-annihilation characteristics of these trapped positrons are found to be very sensitive to hydrogen exposure. The momentum distribution of the annihilating positron–electron pair, as observed in the Doppler broadening of the annihilation line, broadens considerably after exposure to hydrogen. The effect recovers after annealing at , suggesting a hydrogen binding at the interface of ~3 ± 0.3 eV.
TL;DR: In this article, a method for deconvolution of blurred images that uses photon counting Poisson statistics to determine the most probable solution is described, which ensures that the final solution is physically meaningful and consistent with the observations.
Abstract: A method for the deconvolution of blurred images that uses photon counting Poisson statistics to determine the most probable solution is described. The method ensures that the final solution is physically meaningful and consistent with the observations. The developed algorithm is tested with real blurred data, and the result is compared with other methods. These tests show that the algorithm produces stable results that are in good agreement with the true answer.
TL;DR: In this article, the authors used positrons as a tool to study and profile dilute concentrations of defects in solids, and they measured the positron lifetime using two basic techniques.
Abstract: Over the last 10 years, positrons have been used as a tool to study and profile dilute concentrations of defects in solids. The two basic techniques involve the measurement of the positron lifetime...
TL;DR: In this paper, the principal value of an integral can be considered the convergent part of a divergent integral, an interpretation that is almost trivial for simple poles, but more meaningful for higher order poles.
Abstract: The notion of the principal value of an integral is generalized to treat higher order singularities. The principal value of an integral can be considered the "convergent part" of a divergent integral, an interpretation that is almost trivial for simple poles, but more meaningful for higher order poles. Application of this concept leads to a simple algorithm that may be applied to the evaluation of a class of integrals arising in mathematical physics. Many of these integrals frequently occur in the analytic and numerical evaluation of folding functions arising from the product of single-particle Green's functions.
TL;DR: In this paper, the stacked foil activation technique and Ge(Li) γ-ray spectroscopy have been employed for the determination of the excitation functions, up to 60
Abstract: The stacked foil activation technique and Ge(Li) γ-ray spectroscopy have been employed for the determination of the excitation functions, up to 60 MeV, of six reactions, 69Ga(α,n), (α,2n), (α,3n), (α,p3n); 71Ga(α,n) and (α,4n). Since natural gallium used as the target has two odd-mass stable isotopes of abundance, 69Ga(60.1%) and 71Ga(39.9%), their activation in some cases gives the same residual nucleus through different reaction channels, but with very different Q values. In such cases, the individual reaction cross sections are separated with the help of the ratio of their theoretical cross sections. A preliminary theoretical comparison with the preequilibrium geometry-dependent hybrid (GDH) model has been done using an initial exciton number no = 4 (2n + 2p + 0h), and general agreement was found for all reactions at high energies.
TL;DR: In this article, the spectrum of antimony was photographed in the 575-2300-A region (1A = 10−10m) using a hollow cathode and a triggered spark source.
Abstract: The spectrum of antimony was photographed in the 575–2300 A region (1A = 10−10 m) using a hollow cathode and a triggered spark source. The analysis of the 5s25p2 − (5s25p5d + 5s5p3 + 5s25p6s + 5s25p7s) transitions in Sb II spectrum was revised and interpreted on the basis of multiconfiguration interaction calculations. Accurate wavelength measurements of Sb III lines lead to a revised ground-state 5s25p2P interval value of 6574.5 cm−1.
TL;DR: The diffusion coefficient of hydrogen in crystalline silicon, obtained from recent profiling experiments such as nuclear resonance retention and secondary-ion mass spectroscopy, is 3-9 orders of magnitude smaller than the previously accepted value measured by Van Wieringen and Warmoltz in 1956.
Abstract: The diffusion coefficient of hydrogen in crystalline silicon, obtained from recent profiling experiments such as nuclear resonance retention and secondary-ion mass spectroscopy, is 3–9 orders of magnitude smaller than the previously accepted value measured by Van Wieringen and Warmoltz in 1956. Here we point out several items often overlooked in the analysis of profiling measurements. A limited flux model is proposed to explain the observed results. Predictions by the model are supported by further experiments.
TL;DR: In this article, an all-optical modulator for single-mode guided light at 1.32 µm was demonstrated using molecular beam epitaxy and chemical vapour deposition grown silicon thin films.
Abstract: We demonstrate, using molecular beam epitaxy and chemical vapour deposition grown silicon thin films, an all-optical modulator for single-mode guided light at 1.32 μm. A control beam of above band-...
TL;DR: In this article, the properties of a typical X-ray imaging material amorphous Se0.997As0.003, chlorinated in the ppm range were investigated using thermal microhardness analysis and differential scanning calorimetry (DSC).
Abstract: Mechanical and thermal properties of a typical X-ray imaging material amorphous Se0.997As0.003, chlorinated in the ppm range were investigated using thermal microhardness analysis (TμHA) and differential scanning calorimetry (DSC). The experiments were carried out over a temperature range encompassing the glass transformation to study the nature of structural changes controlling the mechanical and thermal properties. It is shown that the mechanical property microhardness when examined on an Itoh–Shishokin plot of log Vickers hardness number (VHN) vs. temperature (T) exhibits a hardness transition temperature, Tg*, in the glass transformation region. The rates of relaxation of the mechanical and thermal properties in the glass transformation region were studied by investigating the heating rate dependence of the glass transition temperatures, Tg* and Tg, defined empirically on the log VHN vs. T behavior and the DSC glass transformation endotherm, respectively. By applying the present thermoanalytical metho...
TL;DR: In this article, a supersymmetric quantum mechanics method for calculating the energy eigenvalues of the Schrodinger equation is presented. But this method is not suitable for the case of power-law potentials.
Abstract: A systematic procedure using supersymmetric quantum mechanics is presented for calculating the energy eigenvalues of the Schrodinger equation. Starting from the Hamiltonian for a given potential-energy function, a sequence of supersymmetric partners is derived such that the ground-state energy of the kth one corresponds to the kth eigen energy of the original potential. Various theoretical procedures for obtaining ground-state energies, including a method involving a rational-function approximation for the solution of the Ricatti equation that is outlined in the present paper, can then be applied. Illustrative numerical results for two one-dimensional parity-invariant model potentials are given, and the results of the present procedure are compared with those obtainable via other methods. Generalizations of the method for arbitrary power-law potentials and for radial problems are discussed briefly.
TL;DR: In this article, the problem of scattering by a radially inhomogeneous cylindrical dielectric shell due to an incident Gaussian beam is solved by a boundary value procedure after first adapting a simplification proposed by Kozaki.
Abstract: The problem of scattering by a radially inhomogeneous cylindrical dielectric shell due to an incident Gaussian beam is solved by a boundary-value procedure after first adapting a simplification proposed by Kozaki. The scattering coefficient is expressed as a product of the scattering coefficient due to an incident plane wave and a weighting function. Both transverse magnetic and transverse electric polarizations of the incident beam source are considered, and some representative numerical results of the scattered power pattern and the normalized backscattering cross section are presented for two specific inhomogeneous profiles. The variations of these quantities with the physical parameters of the dielectric shell are studied.
TL;DR: In this article, single crystals of CuInSe2 have been fabricated by the vertical Bridgman method using a conventional Czochralski crystal-pulling system adapted for this purpose.
Abstract: Single crystals of CuInSe2 have been fabricated by the vertical Bridgman method. A conventional Czochralski crystal-pulling system was adapted for this purpose. An accelerated crucible-rotation tec...
TL;DR: In this paper, the effects of viscosity on the gravitational collapse of a radiating sphere are calculated by extending the Herrera-Jimenez-Ruggeri method to the case of viscous fluids.
Abstract: The effects of viscosity on the gravitational collapse of a radiating sphere are calculated by extending the Herrera–Jimenez–Ruggeri method to the case of viscous fluids. An explicit model is worked out, indicating that when both the shear and bulk viscosity are nonvanishing, the final configuration is less compact than that corresponding to a nonviscous fluid.
TL;DR: In this article, the ν3 fundamental of 28SiF4 has been investigated with laser sidebands and infrared radio-frequency double resonance with a Hamiltonian developed up to sixth order.
Abstract: The ν3 fundamental of 28SiF4 has been investigated with laser sidebands and infrared radio-frequency double resonance. From 165 infrared and 206 pure rotational transitions, 10 ground state and 22 excited state constants have been determined. The calculation was performed with a Hamiltonian developed up to sixth order.
TL;DR: In this paper, a binomial expansion in evaluating integrals involving the two-and three-parameter Fermi or Woods-Saxon functions is shown to be possible because of bounded convergence and integrability.
Abstract: It is shown that a binomial expansion in evaluating integrals involving the two- and three-parameter Fermi or Woods–Saxon function is possible because of bounded convergence and integrability. New results involving analytic expressions with the three-parameter Fermi function for integrals encountered in evaluating the nuclear moments ,the generalized moments , and the radial Fourier transforms are presented. Also as a new result, an expression for the radial Fourier transform of the square of the two-parameter Woods–Saxon density is obtained, and the solution for the three-parameter density is indicated.
TL;DR: In this paper, the photovoltaic response of the n-ZnO-single crystal p-CdTe devices was good, while that of the N-ZNO -single crystal Zn3P2 polycrystalline film devices was poor.
Abstract: "Heterojunctions" have been fabricated by the reactive evaporation of thin film n-type ZnO onto p-type single crystal Zn3P2, polycrystalline films of Zn3P2, and single crystal CdTe. The photovoltaic response of the n-ZnO – single crystal p-CdTe devices was good, that of the n-ZnO – single crystal p-Zn3P2 devices was poor, and that of the n-ZnO – p-Zn3P2 polycrystalline film devices was nonexistent. The ideality factor n of all devices studied was greater than two. On the basis of 1/C2 vs. V results, the n-ZnO – single crystal p-Zn3P2 devices behaved most like Schottky barrier devices, whereas the n-ZnO – p-Zn3P2 polycrystalline film devices, and the n-ZnO – p-single crystal CdTe "heterojunctions" behaved most like metal–insulator–semiconductor devices. The high series resistance of all devices had to be considered in the measurement and analysis, and it limited the photovoltaic performance. Deep-level transient spectroscopy measurements indicated majority (hole) traps in the CdTe and Zn3P2 with activation...
TL;DR: The quantum defect orbital method, including core-polarization effects through an effective dipole-moment transition operator, has been followed to calculate oscillator strengths involving the sharp and diffuse series in the alkali atoms as discussed by the authors.
Abstract: The quantum defect orbital method, including core-polarization effects through an effective dipole-moment transition operator, has been followed to calculate oscillator strengths involving the sharp and diffuse series in the alkali atoms. Comparisons are made among various theoretical and experimental results and those predicted here. It is shown that the formalism adequately describes transitions in subordinate series of the alkali atoms.
TL;DR: Reflection high-energy electron diffraction investigations of CdTe films grown on (001) GaAs have been carried out in this article, where the films were deposited with a pulsed laser evaporation and epitaxy system.
Abstract: Reflection high-energy electron diffraction investigations of CdTe films grown on (001) GaAs have been carried out. The films were deposited with a pulsed laser evaporation and epitaxy system which...
TL;DR: A comparative study of the role of surface effects in the sensitivity of lateral magnetotransistors and magnetodiodes is presented in this article, where both types of devices are realized in standard complementary metal oxide semiconductor technology.
Abstract: A comparative study of the role of surface effects in the sensitivity of lateral magnetotransistors and magnetodiodes is presented. The surface potential at the Si–SiO2 interface is changed by means of the gate voltage. Both types of devices are realized in standard complementary metal oxide semiconductor technology. The results indicate that improvement of the sensitivity can be achieved in both cases, but the dependence of sensitivity of magnetotransistor on surface effects is much lower than that of magnetodiode.
TL;DR: Using H2O as a transport agent, epitaxial GaAs layers were grown by the close-spaeed vapor transport technique (CSVT) on (100) heavily Si-doped GaAs substrates as mentioned in this paper.
Abstract: Using H2O as a transport agent, epitaxial GaAs layers were grown by the close-spaeed vapor transport technique (CSVT) on (100) heavily Si-doped GaAs substrates. Three kinds of GaAs sources were use...