Showing papers in "Canadian Journal of Physics in 1988"
TL;DR: The unified method described previously for combining high-precision nonrelativistic variational calculations with relativistic and quantum electrodynamic corrections is applied to the 1s2 1S0, 1s 2 S 0, 1 s 2 S 1S 0 as discussed by the authors.
Abstract: The unified method described previously for combining high-precision nonrelativistic variational calculations with relativistic and quantum electrodynamic corrections is applied to the 1s2 1S0, 1s2...
357 citations
TL;DR: In this paper, the generalized electrodynamics proposed by Podolsky is analyzed from the Hamiltonian point of view, using Dirac theory for constrained systems, and the problem of gauge fixing for the theory is studied in detail and the correct generalization of the radiation gauge is obtained.
Abstract: The generalized electrodynamics proposed by Podolsky is analyzed from the Hamiltonian point of view, using Dirac theory for constrained systems. The problem of gauge fixing for the theory is studied in detail and the correct generalization of the radiation gauge is obtained, a subject that has not been examined correctly in the earlier literature. The Dirac brackets for the dynamical variables in this gauge are calculated.
71 citations
TL;DR: Water vapor Fourier transform spectra have been analyzed between 8000 and 9500 cm−1 as discussed by the authors, with an average uncertainty of about 10% for the second hexad of H216O.
Abstract: Water vapor Fourier-transform spectra (resolution = 0010 cm−1) have been analyzed between 8000 and 9500 cm−1 Accurate values of 441 rotational energy levels, belonging to the vibrational states (050), (130), (031), (210), (111), and (012) of the second hexad of H216O, have been determined Moreover, 500 line intensities have been accurately measured (uncertainty = 6%) To increase the number of experimental intensities (useful for atmospheric applications), we have set up a less sophisticated but faster method; this has led to the measurement of 1200 additional intensities, with an average uncertainty of about 10%
55 citations
TL;DR: An exact treatment using the boundary value method for solving the problem of scattering of a line-source field or a plane wave by a perfectly conducting elliptic cylinder coated with a confocal di... as mentioned in this paper.
Abstract: An exact treatment using the boundary-value method for solving the problem of scattering of a line-source field or a plane wave by a perfectly conducting elliptic cylinder coated with a confocal di...
42 citations
TL;DR: In this paper, the IR Atmospheric (0-0) band emission in the sunlit mesosphere, which were coordinated with an overpass of the Solar Mesospheric Explorer (SME) satellite, is reported.
Abstract: Rocket measurements of the IR Atmospheric (0–0) band emission in the sunlit mesosphere, which were coordinated with an overpass of the Solar Mesospheric Explorer (SME) satellite, are reported. The IR Atmospheric band volume emission rates, derived from the data obtained with a matching pair of 1.27 μm radiometers, are presented and compared with the emission rates inferred from limb-scan observations made with the near-infrared spectrometer on the SME satellite. The rocket measurements are used to derive the ozone and atomic oxygen number densities in the sunlit mesosphere. The derived concentrations are compared with those obtained from other observations and model calculations.
41 citations
TL;DR: In this paper, the radial density distributions of excited atoms in plasma columns of helium, neon, and argon, sustained by a travelling electromagnetic surface wave, are examined as a function of frequency over the range 200 kHz -2450 kHz.
Abstract: Radial density distributions of excited atoms in plasma columns of helium, neon, and argon, sustained by a travelling electromagnetic surface wave, are examined as a function of frequency over the range 200 kHz – 2450 MHz. This investigation is conducted using an end-on measurement method. At low frequencies ( 300 MHz) yields larger cross-section average densities for atoms in a metastable or resonant state, typically a factor of 2–3 at 1011 electrons∙cm−3. This result arises because the two types of...
33 citations
TL;DR: In this article, a review of parity violation in nucleon systems using polarized beams of slow neutrons is presented, and some suggestions and predictions for the future are also made about the future.
Abstract: In this paper we review the work that has been done on studies of parity violation in nucleon systems using polarized beams of slow neutrons, first describing an early attempt by Haas et al. (Phys. Rev. 116, 1211 (1959)) and ending with some suggestions and predictions for the future.
32 citations
TL;DR: In this article, the beam-foil spectroscopy was applied to obtain measurements of the lifetimes of the 6s6p1P1, 3P 1, 6s 6d1D2, 3D 1,3D 2, and 3D 3 levels of Hg I and the 6p2P1/2, 2P 3/2 and 6d2D3/2.
Abstract: The techniques of beam-foil spectroscopy are applied to obtain measurements of the lifetimes of the 6s6p1P1, 3P1, 6s6d1D2, 3D1, 3D2, and 3D3 levels of Hg I and the 6p2P1/2, 2P3/2, 6d2D3/2, 2D5/2, and 7s2S1/2 levels of Hg II. The energy loss sustained by the ions in passing through the carbon foil is determined using an extended Doppler-shift technique. Constrained curve-fitting and arbitrarily normalized decay curve analyses are used to overcome problems caused by blending between transitions from the 6s6d1D2 and 3D1 levels of Hg I. The f values obtained from the resonance transitions are 1.14 ± 0.04 (Hg I) and 0.648 ± 0.022 (Hg II), in agreement with the trends found previously for higher Z ions in the Hg I and Au I isoelectronic sequences.
27 citations
TL;DR: In this paper, the first order transformed dipole moment of tetrahedral XY4 molecules is studied using a tetralayer formalism and a set of calculated and adjusted parameters is given for the 12CH4 molecule.
Abstract: The first order transformed dipole moment of tetrahedral XY4 molecules is studied using a tetrahedral formalism. Corresponding expressions of involved parameters are given and discussed, for both isolated bands and polyadic studies. A set of calculated and adjusted parameters is given for the 12CH4 molecule.
25 citations
TL;DR: In this paper, beam-foil intensity decay curves for transitions in the wavelength range from 900 to 2200 A are used to derive the lifetimes of the 6s6p1P1 and 3P1 6s 6d1D2, 6s7s1S0, and 6p21D2 levels of Pb III.
Abstract: Beam-foil intensity decay curves for transitions in the wavelength range from 900 to 2200 A are used to derive the lifetimes of the 6s6p1P1 and 3P1 6s6d1D2, 6s7s1S0, and 6p21D2 levels of Pb III, and the 6p2P1/2 and 2P3/2, 6d2D3/2 and 2D5/2, 7s2S1/2, and 5d96s22D3/2 levels of Pb IV, arbitrarily normalized decay curve (ANDC) analyses being used for the 6s6p and 6p levels. In the case of the two 6s6p levels studied in Pb III, good agreement is found with a recent calculation in which a polarization model accounts for valence–core correlation. However, the agreement between the lifetimes observed for the 6p levels in Pb IV and a similar, earlier calculation is only fair.
24 citations
TL;DR: In this article, the authors focus on image contrast optimization between two rough-surface classes using polarimetric filtering, and no digital image-processing technology is used to perform image-contrast optimization.
Abstract: In this paper we focus on image-contrast optimization between two rough-surface classes. Our approach is based strictly on polarimetric filtering, and therefore, no digital image-processing techniq...
TL;DR: In this paper, the properties of dip-coated thin films prepared from colloidal silica and titania solutions have been examined, and the effects of withdrawal rate, heat treatment, and solution concentration on film thickness, refractive index, and other properties have been studied.
Abstract: The properties of dip-coated thin films prepared from colloidal silica and titania solutions have been examined. The effects of withdrawal rate, heat treatment, and solution concentration on film thickness, refractive index, and other properties have been studied. Results show that extremely uniform and reproducible thin films with refractive indices between 1.46 and 2.08 and thicknesses up to 0.25 μm can be produced with a single dip. The refractive index of the SiO2:TiO2 composite films varies linearly with the volume fraction of TiO2, and the thickness varies linearly with withdrawal rate. The effects of drying on the final thin film properties are minimal; however, baking conditions have a significant effect, with films shrinking up to 50% and the refractive index increasing 40% during baking. The resulting films are hard, durable, and of good optical quality. We have studied these films for use as planar optical waveguides; however, the results are also applicable to films made for various uses such ...
TL;DR: In this article, variable reflectivity mirrors (VRMs) are used to improve the near and far-field optical quality of unstable laser resonators, and experimental results obtained using different lasers with Cassegrain cavities are presented.
Abstract: Global efficiency, transverse mode discrimination, and the near- and far-field optical quality of unstable laser resonators are improved with variable reflectivity mirrors (VRMs). Analytical and numerical results are given for Gaussian and parabolic reflectivity mirrors. The VRM design is described, and experimental results obtained using different lasers with Cassegrain cavities are presented.
TL;DR: In this paper, an ion-acoustic soliton in an ionbeam plasma system was studied using the renormalization procedure of Kodama and Taniuti in the reductive perturbation method and an alternative meth-merchant method.
Abstract: Propagation of an ion-acoustic soliton in an ion-beam plasma system is studied using the renormalization procedure of Kodama and Taniuti in the reductive perturbation method and an alternative meth...
TL;DR: In this article, a detailed description is given of a technique in which emissions from H and H2 are used to calibrate an apparatus used for electron-impact emission cross-section measurements in the wavelength range 90-130 nm.
Abstract: A detailed description is given of a technique in which emissions from H and H2 are used to calibrate an apparatus used for electron-impact emission cross-section measurements in the wavelength range 90–130 nm. Absolute emission cross sections have been measured at 200 eV electron-impact energy for the 120 nm N I line following dissociative excitation of N2 and for the Ar and Ar+ lines at 104.8, 106.7, 92.0, and 93.8 nm respectively. Good agreement with earlier works is obtained in the case of the N I line when earlier data are renormalized to take into account the recent revision of the cross section for production of Lyman α from H2. Measurements of the 104.8 and 106.7 nm lines suggest a 40% cascade component for the latter line at energies of 200 eV and above.
TL;DR: In this paper, the feasibility of the photothermal surface deformation (PTD) technique for a highly sensitive, completely contactless detection, as well as a lateral and depth-resolved localization, of absorption in optical thin films was shown both theoretically and experimentally.
Abstract: The purpose of this paper is to show both theoretically and experimentally the feasibility of the photothermal surface-deformation (PTD) technique for a highly sensitive, completely contactless detection, as well as a lateral and depth-resolved localization, of absorption in optical thin films. Peculiarities in the interpretation of the measuring signal, such as the influence of the thermal-expansion coefficient of the substrate and the focal diameter of the heating beam, have been pointed out.As a relevant example, the absorption of evaporated ZrO2, single layers on BK 7 substrates has been measured at λ = 515 nm. Their bulk absorption is shown to be strongly influenced by both deposition parameters and the baking procedure.
TL;DR: In this paper, the collision-induced spectrum of a mixture of argon and acetylene (100:1) was reported in the frequency range below 240 cm−1, with a Michelson Fourier-transform interferometer and with a laser source at 84.1 cm −1.
Abstract: The collision-induced spectrum of a mixture of argon and acetylene (100:1) is reported in the frequency range below 240 cm−1. The spectrum is obtained from the total absorption in the mixture at pressures up to 1400 psi (1 psi = 6.89 kPa) and subtraction of the contribution from an allowed difference band of pure acetylene centred near 113 cm−1. The measurements are made with a Michelson Fourier-transform interferometer and with a laser source at 84.1 cm−1. The quadrupole moment of acetylene determined from the experimental spectrum and existing theory for the integrated absorption coefficient is 5.42 (± 0.41) B if a theoretical estimate of the hexadecapole moment is used. Alternatively, a value of 6.14 (± 0.46) B is obtained if the contribution from the hexadecapole moment is assumed to be zero. An extension of the line-shape theory, 1T6, that includes the contribution from hexadecapolar induction is also reported. The resulting theoretical line shape is compared with the experimental spectrum.
TL;DR: In this article, the helicity-dependent component of the total cross section for the production of bremsstrahlung on tantalum by longitudinally polarized electrons has been measured.
Abstract: The circular polarization dependent component of the total cross section for photodisintegration of deuterium has been measured: (2.7 ± 2.8) × 10−6 for bremsstrahlung with an end point of 4.1 MeV and (7.7 ± 5.3) × 10−6 for an end point of 3.2 MeV. The helicity-dependent component of the total cross section for the production of bremsstrahlung on tantalum by longitudinally polarized electrons has been measured: (0.63 ± 0.70) × 10−6 for an electron energy of 4.1 MeV and (3.1 ± 1.5) × 10−6 at 3.2 MeV. All measurements are in agreement with theoretical predictions for these processes.
TL;DR: In this article, the authors studied the gauge dependence of the static characteristics of charged leptons in the framework of the GSW (Glashow-Salam-Weinberg) model.
Abstract: The gauge dependence of the static (q2 = 0) characteristics of charged leptons in the framework of the GSW (Glashow–Salam–Weinberg) model was studied. It was found that the anapole moments of lepto...
TL;DR: In this article, it was shown that a mild reality constraint on the radial part of the resolution generator renders the probability current for a single particle with only positive (or only negative) energies and having arbitrary integer spin conserved.
Abstract: Working within the framework of stochastic quantum mechanics, we prove that a mild reality constraint on the radial part of the resolution generator renders the (probability) current, for a single particle with only positive (or only negative) energies and having arbitrary integer spin, conserved. The result is proven both nonrelativistically and relativistically. This extends some earlier results that had been obtained for spinless systems. We argue that the origin of such a conservation law is a consequence of the particular geometry of space–time predicated by the formalism of stochastic quantum mechanics.
TL;DR: In this article, the excitation energies and the length and velocity forms of the optical oscillator strengths for the resonance 1s22s22p63s2Se → 1s 22s 22p63p2P0 transition and the nonresonance 1s...
Abstract: We have calculated the excitation energies and the length and velocity forms of the optical oscillator strengths for the resonance 1s22s22p63s2Se → 1s22s22p63p2P0 transition and the nonresonance 1s...
TL;DR: In this paper, the oscillator strength distribution between the discrete and continuous regions of the spectra of Mg, Ca, Sr, and Ba has been obtained using the Quantum Defect Orbital (QDO) method.
Abstract: The oscillator strength distribution between the discrete and continuous regions of the spectra of Mg, Ca, Sr, and Ba has been obtained. Computations have been carried out through the Quantum Defect Orbital (QDO) method, with explicit introduction of the two-electron transitions that lead to resonances in the spectra of the last three elements. Interference effects between excitations to autoionizing levels and to the continuum have been ignored.
TL;DR: The input pixel size of a polarization-encoded optical shadow-casting logic system is reduced by means of truth-table partitioning and this technique leads to an improved memory-efficient optical computing unit.
Abstract: The input pixel size of a polarization-encoded optical shadow-casting logic system is reduced by means of truth-table partitioning. The proposed design algorithm is used to encode the inputs of a three-input, two-output binary full adder. A comparison with alternative designs proves that the technique leads to an improved memory-efficient optical computing unit.
TL;DR: In this article, the main emphasis is on p−p scattering below pion threshold and how effects depend on strong interaction physics, in particular, the well-determined p −p scattering phase shifts.
Abstract: Methods of analysis of parity violation in scattering experiments are presented. The main emphasis is on p–p scattering below pion threshold. It is shown how effects depend on strong interaction physics, in particular, the well-determined p–p scattering phase shifts. The different physical content of the two lowest parity-violating partial wave scattering amplitudes is discussed, as is the optimal choice of energy for their determination. The crucial role of the different anomalous magnetic-moment couplings for the analysis of parity-violating ρ and ω exchange is emphasized. The unexpectedly large parity violation found at 6 GeV/c proton momentum is then discussed with the conclusion that no satisfactory explanation yet exists. At the end, p–α and p–d scattering are discussed briefly.
TL;DR: In this article, the definitions of the static properties of charged leptons within the Glashow-Salem-Weinberg model are equivalent in both the singlet fields and the Rξ gauge fields, at least in the...
Abstract: We found that the definitions of the static properties of charged leptons within the Glashow–Salem–Weinberg model are equivalent in both the singlet fields and the Rξ gauge fields, at least in the ...
TL;DR: In this paper, the insertion of a nonlinear medium into one arm of a Michelson interferometer used as a mirror in a laser cavity is shown to produce intensity-dependent losses.
Abstract: The insertion of a nonlinear medium into one arm of a Michelson interferometer used as a mirror in a laser cavity is shown to produce intensity-dependent losses. The resulting nonlinearity yields passive mode locking since it favors the oscillation of an intense short pulse. The method is analyzed and compared with passive mode locking with a saturable absorber. The duration of the short pulse circulating in the laser cavity is shown to be ultimately limited by the linewidth of the gain curve. Experimental results obtained with a transversely excited atmospheric – CO2 laser illustrate some aspects of the dynamic behaviour of a laser equipped with such a device.
TL;DR: In this paper, the authors investigated the contribution of hyperfine predissociation in spin-polarized atomic hydrogen (H↓) to the reaction kinetics in H↓ due to the resonance arising from the (v,J) = 14,4 level of H2.
Abstract: In sufficiently large magnetic fields, the weakly bound levels of H2 acquire finite lifetimes owing to hyperfine predissociation and become manifest as scattering resonances in spin-polarized atomic hydrogen (H↓). In this work we investigate in detail the contribution to the reaction kinetics in H↓ due to the resonance, denoted , arising from the predissociation of the (v,J) = (14,4) level of H2. To characterize the formation and disintegration of , we calculate the predissociation as a function of both the applied magnetic field and the dissociation energy, D, of the level. Recombination occurs when is stabilized in collisions that cause transitions to lower molecular levels. For low H↓, densities, collisions with atoms of the saturated 4He vapour dominate; we calculate the cross section in the distorted wave Born approximation and also use a coupled-channels approach. At higher densities, stabilization occurs in collisions with H↓ as well; the effect of proton exchange between the atom and the molecule ...
TL;DR: In this article, an all-optical mode cutoff modulator for fiber optics systems working at wavelengths in the 1.3-1.6-μm range is described.
Abstract: We describe an all-optical mode cutoff modulator for use in fiber optics systems working at wavelengths in the 1.3–1.6-μm range. The active waveguide is silicon grown by molecular beam epitaxy, and the channels are fabricated by conventional lithographic techniques and used with standard single-mode fibers. Subnanosecond initiation and recovery times are achieved with less than 150 pJ of control energy in a three-port geometry suitable for use as a logic gate. We also present preliminary results when the guided light is near the bandgap energy and demonstrate self-limiting for integrating Kerr-like self-defocussing nonlinearities. In both cases, the operation of the device is largely wavelength independent and stable.
TL;DR: In this paper, seven bands belonging to the Herzberg system of 13C18O have been recorded in emission using conventional photographic spectroscopy for the first time and identified after the rotational analysis of bands.
Abstract: Seven bands ((0–0) – (0–6)) belonging to the Herzberg system of 13C18O have been recorded in emission using conventional photographic spectroscopy For the first time, lines of this system have been recorded at high resolution and identified After the rotational analysis of bands, the rotational constants of the C1Σ+ (ν = 0) and A1Π (ν = 0–6) states, as well as the vibrational constants of the A1Π state, have been determined A combined analysis of the bands of the Herzberg and Angstrom systems have made it possible to determine the constants of the B1Σ+ state more precisely Numerous rotational perturbations observed in the A1Π state in this isotopic molecule have been analyzed
TL;DR: Eigenvalue equations for multilayer waveguides are given in this article, along with equations for the field distributions, and closed analytic expressions are given to calculate the mode number of the waveguide.
Abstract: Eigenvalue equations for guided modes in multilayer waveguides are given, along with equations for the field distributions. Closed analytic expressions are given to calculate the mode number of the...