Showing papers in "Canadian Journal of Physics in 1977"
TL;DR: In this paper, the Coriolis interaction between ν2 and ν4 of CH4 has been studied using an unsymmetrized coupling scheme in the group Td.
Abstract: Using an unsymmetrized coupling scheme in the group Td, we determine all the vibration–rotation operators of the Hamiltonian of XY4 molecules, including all possible interactions, up to any order of approximation. We define a basis of Hamiltonian matrices of which the matrix elements are functions of coupling coefficients of the group chain only. Thus, we develop a general formalism available for any vibrational sublevels of whatever symmetry. The parameters relative to the different vibrational sublevels are known linear combinations of the coefficients of the Hamiltonian expansion. From these, we deduce simple relations between the parameters associated with the ground state, the fundamentals, and the harmonic and combination bands.We apply this formalism to the study of the Coriolis interaction between ν2 and ν4 of CH4. With only 21 parameters for the two bands, we obtain a standard deviation of 34 mK for 251 Raman transitions of ν2 and 20 mK for 243 ir transitions of ν4.
166 citations
TL;DR: In this article, the authors have constructed a dipole oscillator strength distribution (DOSD) for ground state Li, N, O, H2, N2, NH3, NH4, NH5, NH6, NH7, NH8, NH9, NH10, NH11, NH12, NH13, NH14, NH15, NH16, NH17, NH18, NH20, NH21, NH2O, NO, and N2O using photoabsoiption and high energy electron inelastic scattering cross sections.
Abstract: Dipole oscillator strength distributions (DOSDs) have been constructed for ground state Li, N, O, H2, N2, O2, NH3, H2O, NO, and N2O by using experimental and theoretical photoabsoiption and high energy electron inelastic scattering cross sections Each DOSD is required to satisfy the Thomas–Reiche–Kuhn sum rule and additional constraints derived from available accurate experimental refractivity and dispersion measurements The DOSDs, the data and procedure used to construct the DOSDs, and the values of the dipole oscillator strength sums Sk and Lk (for a variety of k values) and related atomic and molecular properties obtained from the DOSDs are reported The discussion includes comments regarding the importance of the constraints imposed on the DOSD with respect to the evaluation of various dipole sums and properties and the accuracy of the results
121 citations
TL;DR: In this article, the problem of scattering of electromagnetic waves of arbitrary frequency by a homogeneous, isotropic sphere which carries excess surface charges was solved under the assumption that there exists a linear relation between surface current density and electric field.
Abstract: The problem of scattering of electromagnetic waves of arbitrary frequency by a homogeneous, isotropic sphere which carries excess surface charges can be solved under the assumption that there exists a linear relation between surface current density and electric field The scattering coefficients so obtained are formally different from those in the standard Mie–Debye theory Whether or not there is any observable difference between scattering by a charged and otherwise identical uncharged sphere depends upon the value of a phenomenological surface conductivity or, equivalently, surface dielectric function For sufficiently small particles the effect of surface charges is merely additive, the effective dielectric function is the sum of bulk and surface dielectric functions
112 citations
TL;DR: In this article, the entire matrix which connects "standard" to "cubic normal" components of spherical tensors is defined and the numerical values of the matrix elements are given up to J √ 15.
Abstract: The entire matrix which connects 'standard' to 'cubic normal' components of spherical tensors is defined. Numerical values of the matrix elements are given up to J = 15. The results may be used for proper or improper groups (SO(3), O(3) – O, Td, Oh) useful in atomic and molecular physics.
91 citations
TL;DR: In this paper, the structure of both bound excitons and bound multiexciton complexes in donor and acceptor doped Si was analyzed using high-resolution photoluminescence spectra.
Abstract: The high resolution photoluminescence spectra reported here reveal new details of the structure of both bound excitons and bound multiexciton complexes in donor and acceptor doped Si. The bound exc...
70 citations
TL;DR: In bulk and thin film metal samples, a net migration of material may take place when electrical current is passed through the sample at an elevated temperature as discussed by the authors, due to the passage of the current through the material.
Abstract: In bulk and thin film metal samples, a net migration of material may take place when electrical current is passed through the sample at an elevated temperature. The migration is due to the passage ...
70 citations
TL;DR: In this paper, the first order Raman spectrum of the layer type semiconducting compound, WSe2, has been investigated and the frequencies of the Raman active A1g, E2g1E1G, and E 2g2 modes have been determined to be 25.
Abstract: The first order Raman spectrum of the layer type semiconducting compound, WSe2, has been investigated. The frequencies of the Raman active A1g, E2g1E1g, and E2g2 modes have been determined to be 25...
59 citations
TL;DR: In many polycrystalline ceramic materials the transport properties are strongly affected by internal barrier effects or by the presence of contact barriers as mentioned in this paper, and the degree to which these barriers affect the measured transport properties has been established.
Abstract: In many polycrystalline ceramic materials the transport properties are strongly affected by internal barrier effects or by the presence of contact barriers. The transport properties of La1−xSrxCrO3, 0 ≤ x ≤ 0.2 have been investigated and the degree to which these barriers affect the measured transport properties has been established. Measurements of the dc and ac conductivity in the range 77 K ≤ T ≤ 1300 K are consistent with the hopping of polarons in a defect band of localized states at the Fermi energy with the thermopower essentially independent of temperature. A polaron radius of 3.5 A has been determined with room temperature mobility of 5 × 10−4 cm2 V−1 s−1.
52 citations
TL;DR: In this article, simple lattice dynamical models have been fitted to the experimental phonon dispersion curves of niobium, molybdenum, and their alloys.
Abstract: Simple lattice dynamical models have been fitted to the experimental phonon dispersion curves of niobium, molybdenum, and their alloys. The 'best-fit' parameters are used to compute the phonon distribution functions, g(v), and several properties which depend on these functions.
52 citations
TL;DR: In this paper, it was shown that many features of the recombination luminescence attributed to bound multiexciton complexes (BMEC) in Si can be understood in terms of a shell model.
Abstract: It is shown that many features of the recombination luminescence attributed to bound multiexciton complexes (BMEC) in Si can be understood in terms of a shell model. Zeeman and stress-split spectra of phosphorus BMEC's are explained by the model and luminescence lines which were originally predicted by the model have been observed. A qualitative interpretation of the energies of the BMEC recombination photons is given. The intensities of acceptor bound exciton and BMEC luminescence lines are explained for the first time. A formal treatment of no-phonon recombination in indirect gap semiconductors is given and related to the observed spectra.
52 citations
TL;DR: In this paper, a simple sensitive method of observing coherent multiphoton transitions by observation of subsequent photoionization is described, which has been applied to a study of molecular iodine leading...
Abstract: A simple, sensitive method of observing coherent multiphoton transitions by observation of subsequent photoionization is described.The method has been applied to a study of molecular iodine leading...
TL;DR: In this article, it was suggested that the force was due to the action of a tangential electric field component acting on the induced surface charge of the metal coating, which appeared as a surface drag on a thin metal coating applied to the dielectric.
Abstract: Experimental evidence is obtained indicating a mechanical force in a dielectric subjected to crossed electric and magnetic fields consistent with the predictions of the Abraham energy momentum tensor. In the course of the experiment a most unusual force was observed, which appeared as a surface drag on a thin metal coating applied to the dielectric. It is suggested that the force was due to the action of a tangential electric field component acting on the induced surface charge of the metal coating.
TL;DR: In this paper, the C, 2 Π, ν ν = 0 state of NO has been investigated using two photon spectroscopy (PS) as a quantitative test of the technique and to study the predissociation of this state.
Abstract: The C, 2Π, ν = 0 state of NO has been investigated using two photon spectroscopy (a) as a quantitative test of the technique and (b) to study the predissociation of this state.The agreement between...
TL;DR: In this article, the microwave absorption spectrum of pairs of H2 molecules at low concentration in solid hydrogen in the frequency ranges 10 −26 and 60 −90 GHz was measured. Observati...
Abstract: Measurements of the microwave absorption spectrum of pairs of (J = 1) H2 molecules at low concentration in (J = 0) solid hydrogen in the frequency ranges 10–26 and 60–90 GHz are reported. Observati...
TL;DR: In this article, the Hartree-Fock approximation of the radial density of the neutral atoms from helium to xenon was used to estimate one-electron properties, including expectation values for rn, n, n −2, −1, 1, 2, 3, 4, and 5.
Abstract: Analytical expansions for the radial density D(r), as calculated within the Hartree–Fock approximation, are reported for the neutral atoms from helium to xenon. As part of a brief discussion of one-electron properties which may be calculated from D(r) or the related density distribution ρ(r), expectation values for rn, n = −2, −1, 1, 2, 3, 4, and 5 are presented.
TL;DR: In this article, rotational and vibrational analysis of 13C2H2O2 in absorption has been carried out for 11 bands of the (π*n) system.
Abstract: Rotational analyses have been carried out for 11 bands of the (π*–n) system of 13C2H2O2 in absorption. Approximately 12 000 lines have been assigned, and rotational and vibrational constants have been evaluated. The following vibrational frequencies have been determined: ν2′ = 1365.17 cm−1, ν4′ = 918.81 cm−1, ν5′ = 502.48 cm−1, ν7′ = 229.40 cm−1, ν7″ = 124.61 cm−1Using the rotational constants for C2H2O2, C2HDO2, C2D2O2, 13C2H2O2, and C2H218O2, the following geometrical parameters have been evaluated: in the A1Au excited state, r0(CH) = 1.115 ± 0.010 A, r0(CO) = 1.252 ± 0.016 A, r0(CC) = 1.460 ± 0.025 A, , ; in the ground state, r0(CH) = 1.109 ± 0.008 A, r0(CO) = 1.202 ± 0.012 A, r0(CC) = 1.527 ± 0.017 A, , . The ground state parameters are in excellent agreement with earlier electron diffraction results.
TL;DR: In this article, the lifetime of the first excited 1P1 level of neutral magnesium has been measured over a wide range of densities and the natural lifetime of 3s3p1P1 levels is 2.00
Abstract: The Hanle width and hence the lifetime of the first excited 1P1 level of neutral magnesium have been measured over a wide range of densities. The natural lifetime of the 3s3p1P1 level is 2.00 ns. T...
TL;DR: The eigenmode of surface plasmon for different geometries is derived in this article for voids and for particles and given the eigensurface mode of spheroids, paraboloids, cones, and multi-edges.
Abstract: The eigenmode of surface plasmon are obtained for different geometries. The results are valid for voids and for particles and give the eigensurface mode of spheroids, paraboloids, cones, and multi-edges. Limiting cases, obtained by asymptotic development, or particular cases useful in some physical situations are studied in more detail: spheroidal or paraboloidal needles or craks, spheroidal or paraboloidal disks, whisker diode geometry, and blades perpendicular to a plane.
TL;DR: In this paper, the magnetic field dependence of the transmission of 24 GHz radiation through ferromagnetic plates of Supermalloy approximately 10−2 cm thick has been investigated using a theory which combines Maxwell's equations and the equation of motion for the magnetization, and which includes the possibility of the external magnetic field lying at any angle with respect to the normal.
Abstract: The magnetic field dependence of the transmission of 24 GHz radiation through ferromagnetic plates of Supermalloy approximately 10−2 cm thick has been investigated. The results have been interpreted using a theory which combines Maxwell's equations and the equation of motion for the magnetization, and which includes the possibility of the external magnetic field lying at any angle with respect to the specimen normal. The results of the measurements on four discs of Supermalloy at 1 °C were very consistent and resulted in the average values g = 2.106 ± 0.001, 4π7Ms = 7.531 ± 0.01 kOe, and a damping parameter, λ = (0.94 ± 0.05) × 108 s−1. Although transmission studies made on specimens thick compared to the skin depth are very useful for obtaining the magnetic damping parameter and magnetostatic parameters, the article also discusses the possibility of using transmission experiments on thinner specimens to study exchange and surface pinning of the magnetization.
TL;DR: In this article, the authors derived a more precise value for the krypton-krypton collision excitation crosssection, S*Kr-Kr −Kr = 1.2 × 10−19 cm2/eV with or without the addition of hydrogen.
Abstract: At shock Mach numbers in pure krypton, at initial pressures p0 ~ 5 Torr, and final electron number densities ne ~ 1017 cm−3, the translational shock front in a 10 cm × 18 cm hypervelocity shock tube develops sinusoidal instabilities which affect the entire shock structure including the ionization relaxation region, the electron-cascade front and the final quasi-equilibrium state. By adding a small amount of hydrogen (~0.5% of the initial pressure), the entire flow is stabilized. However, the relaxation length for ionization is drastically reduced to about one half of its pure-gas value. Unlike argon the stability appears to diminish with the addition of hydrogen beyond about 0.5%. Using the familiar two-step collisional model coupled with radiation-energy loss and the appropriate chemical reactions, it was possible from dual-wavelength interferometric measurements to deduce a more precise value for the krypton–krypton collision excitation cross-section, S*Kr–Kr = 1.2 × 10−19 cm2/eV, with or without the pr...
TL;DR: In this article, the surface magnetic field dependent surface impedance near surface pinning was investigated and the shape of the line was found to be a very complex manner on all layers of the sample.
Abstract: (FMAR) damping, exchange parameter, and surface The FMAR transmission anomaly is a bulk pinning of a ferromagnetic metal (A~~~~ and phenomenon; it is insensitive to surface pinning ~~d~ 1955; ~~d~ and weertlnan 1959). M~~~ and the RF radiation probes the total thickness investigations have been restricted to frequencies of the sample. differs from FMR for which and fields which correspond to ferromagnetic the shape and position of the FMR absorption resonance (FMR). In practice, the shape of the line are de~endellt UP011 the degree of surface magnetic field dependent surface impedance near pinning, and for which a layer approxiFMR depends in a very complex manner on all lnately 1000 A thick is probed by 24 GHz radiathe above parameters, making it difficult to tion. FMAR measurements are therefore far less disentangle effects due to magnetic damping sensitive to the condition of the sample surfaces from effects due to and surface pinning. than FMR measurements and this minimizes
TL;DR: In this paper, the Dunham potential coefficients are numerically determined by using a nonlinear least squares routine applied directly to the line experimental wave numbers, and the results are compared to the ones obtained when using the usual iterative process applied to the H81Br Yi0 and Yi1 equilibrium constants.
Abstract: In this paper, the Dunham potential coefficients are numerically determined by using a nonlinear least squares routine applied directly to the line experimental wave numbers.The results are compared to the ones obtained when using the usual iterative process applied to the H81Br Yi0 and Yi1 equilibrium constants.The al determination new method assumes a theoretical framework (B.O., adiabatic or non-adiabatic) to be valid. One can test this assumption by comparing the experimental data to the calculated ones.
TL;DR: In this paper, the authors measured the elastic and inelastic scattering power and cross-section of 30'MeV polarized protons from 90Zr, 92Zr and 92Mo.
Abstract: Analyzing powers and cross sections have been measured for elastic and inelastic scattering of 30 MeV polarized protons from 90Zr, 92Zr, and 92Mo. The experimental results are analyzed in terms of the coupled-channels formalism using the vibrational model. The best fits for the analyzing power for all the nuclei are obtained by using the full Thomas form for the spin–orbit potential. These calculations give a very good description for both the cross sections and the analyzing powers of the low-lying 2+, 3−, 5−, and 4+ states in 90Zr, 92Zr, and 92Mo. Only a small increase of the spin–orbit deformation over the central deformation (βLS/βcentral = 1.5) is needed to reproduce the data; this is contrary to the situation at lower energy where a large increase of this ratio was required (Raynal). Some differences between the 90Zr–92Mo data (which are similar) and the 92Zr data have also been observed; this is, however, in agreement with previous results at lower energy. Microscopic model calculations with tensor...
TL;DR: The total neutron cross section of pure and O2-doped condensed CH4 has been measured in the temperature range 0.75 ǫ < 0.1 Ã 0.
Abstract: The total neutron cross section of pure and O2-doped condensed CH4 has been measured in the temperature range 0.75 < T < 100 K. The neutron wave length was sufficiently long (4.7 A) so that changes...
TL;DR: In this article, the spectra of cadmium, tin, and antimony have been photographed in the region 600-200 A on 10.7 and 6.6m grazing incidence vacuum spectrographs using triggered spark and a sliding spark as light sources.
Abstract: The spectra of cadmium, tin, and antimony have been photographed in the region 600–200 A on 10.7 and 6.6 m grazing incidence vacuum spectrographs using a triggered spark and a sliding spark as light sources. The analyses of the 4d85p configurations in Cd IV and Sn VI have been revised and extended. The parametric level fitting calculations and relative oscillator strengths calculations of the allowed transitions confirm the present analyses. The separation of the 4d92D multiplet in Sb VII has been determined; its value is 10 405 ± 2 cm−1. Accurate measurements of the resonance lines of Sn V and Sb VI have resulted in raising every level of Sn V by +415 cm−1 and of Sb VI by +5 cm−1.
TL;DR: In this paper, the chemiluminescence technique has been used to measure the growth of stratospheric nitric oxide from before sunrise until about 2h prior to local noon at a constant altitude of 26.5 km at 33.1 °N.
Abstract: The chemiluminescence technique has been used to measure the growth of stratospheric nitric oxide from before sunrise until about 2 h prior to local noon at a constant altitude of 26.5 km at 33.1 °N. The instrument has sufficient time resolution to record the rapid growth of NO due to photolysis of NO2 during ultraviolet sunrise. As well, NO was observed to increase slowly throughout the remainder of the experiment. This slow growth is tentatively assigned to the release of NO2 and NO3 and subsequently NO from the photolysis of N2O5 formed during the night. A time dependent computer simulation of diurnal measurements is used to investigate the sensitivity of the computed NO growth curves to O3, total NOx, and the photolysis coefficient of N2O5.
TL;DR: In this article, a flowing afterglow study of the reaction He(23S) + SO2+ was performed, which was characterized by a long progression of symmetrical stretching vibrations (ν1′, 0, 0) and a number of bending modes.
Abstract: fluorescence emission was observed and analyzed in the 300–550 nm spectral range from a flowing afterglow study of the reaction He(23S) + SO2. The band system, which has its origin at 333.9 nm, is characterized by a long progression of symmetrical stretching vibrations (ν1′, 0, 0) → (ν1″, 0, 0) for 0 ≤ ν1″ ≤ 2 with and a number of bending modes (0, 0, 0) → (ν1″, ν2″, 0) for with 0 ≤ ν1″ ≤ 9. The symmetrical stretching vibrational frequency of the state was determined to be 1264 ± 10 cm−1 which had not been observed previously. The ν2″ bending frequency of the state of SO2+ was found to be ~404 cm−1. SO(B3Σ− → X3Σ−) and SO2(A1B1 → ) emission is also observed in the He(23S) + SO2 reaction system, but molecular ion fluorescence is the predominant emission system. From a comparison of the emission spectrum produced by helium metastables with that produced by argon (3P2, 0) metastables, it is concluded that neutral excitation and dissociative excitation occur at large interparticle distances while Penning ioni...
TL;DR: The collision-induced light scattering from compressed gaseous CH4 and CF4 has been observed at room temperature at densities up to 100 and 166 amagats, respectively as mentioned in this paper.
Abstract: The collision-induced light scattering from compressed gaseous CH4 and CF4 has been observed at room temperature at densities up to 100 and 166 amagats, respectively. Absolute intensity measurements have been made and the two- and three-body components to the spectra have been identified. A detailed comparison is made with similar data on argon and significant differences emerge between the atomic and molecular cases. The two-body molecular spectra contain an excess of intensity over predictions of the dipole–induced-dipole (DID) model; the argon intensity is less than predicted. At low frequency, the two- and three-body spectra of all species are dominated by the DID interaction. At high frequency the two-body molecular spectra decay much more slowly than the profile due to argon. A moment analysis has been performed wherein the pair polarizability is assumed to be of the form, β(r) = 6α2/r3 + B/rp. The unknown parameters B and p are determined from the experimental zeroth and second moments of the spect...
TL;DR: In this paper, a general Hamiltonian for the interaction of two ortho-H2 molecules in otherwise pure solid para-H 2 is constructed, which takes full account of the local environment.
Abstract: A comprehensive theory is presented for the interaction of two ortho-H2 molecules in otherwise pure solid para-H2. A general Hamiltonian is constructed, which takes full account of the local enviro...
TL;DR: In this article, the (3He,d) and (α,t) reactions have been used to study odd proton states in 157,159,161,163Ho and the results are interpreted in terms of the Nilsson model with pairing and Coriolis mixing included.
Abstract: The (3He,d) and (α,t) reactions have been used to study odd proton states in 157,159,161,163Ho. The beams were provided by tandem Van de Graaff accelerators and the light reaction products were analyzed with magnetic spectrographs and detected with photographic emulsions. Spectra were studied up to excitation energies of ~1.5 MeV for each nuclide with resolutions (FWHM) of ~14 keV for the (3He,d) reaction and ~12 keV for the (α,t) reaction. Information on the l-values was obtained from the ratios of (3He,d) and (α,t) cross sections and from (3He,d) angular distributions. The results are interpreted in terms of the Nilsson model with pairing and Coriolis mixing included. Nuclear structure factors were extracted from the experimental data with the aid of DWBA calculations. Nilsson assignments from previous gamma-ray studies have been confirmed for many low-lying rotational bands. In addition, many new assignments have been made, particularly in the lighter isotopes for which very little nuclear structure in...