Showing papers in "Canadian Journal of Physics in 1983"
TL;DR: In this article, in situ X-ray diffraction results indicate that upon intercalation, the 2H-MoS2 is a semiconductor with a hexagonal layered structure.
Abstract: 2H-MoS2 is a semiconductor with a hexagonal layered structure. Each Mo atom is prismatically coordinated by six S atoms. Our in situ X-ray diffraction results indicate that, upon intercalation, the...
558 citations
TL;DR: In this article, a tensor extension from the Td group to the O(3) group was proposed for the analysis of isolated bands and for the simultaneous analysis of interacting bands.
Abstract: Using a coupling scheme in the Td group, we determine all the vibration–rotation operators of the dipole moment of XY4 molecules up to any order of approximation. We give the matrix elements for these operators and general formulas for the calculation of the infrared transition intensities. This general formalism is available for any transition between vibrational sublevels of any symmetry. It can be used for the analysis of isolated bands and for the simultaneous analysis of interacting bands as well. We show that this method can be applied to the calculation of Raman intensities and to XY6 molecules.In some cases, it is possible to carry out a tensorial extension from the Td group to the O(3) group. We have constructed the operators of the dipole moment adapted to this process using a coupling scheme in O(3). In particular, we give the matrix elements for a triply degenerate band.We use the contact transformation technique to explain the parameters introduced in the formal expansion of the dipole moment...
77 citations
TL;DR: In this paper, the pure rotation spectrum of hydrogen sulfide has been recorded between 50 and 320 cm−1 with a Fourier transform spectrometer at an apodized resolution of 0.005cm−1.
Abstract: The pure rotation spectrum of hydrogen sulfide has been recorded between 50 and 320 cm−1 with a Fourier transform spectrometer at an apodized resolution of 0.005 cm−1. This high resolution and a go...
74 citations
TL;DR: Doppler-free, two-photon spectroscopy has been used to investigate the transitions n2S←52S and n2D← 52S of atomic rubidium as mentioned in this paper.
Abstract: Doppler-free, two-photon spectroscopy has been used to investigate the transitions n2S ← 52S and n2D ← 52S of atomic rubidium, from n = 9 to 116 and n = 7 to 124, respectively, only 7.3 cm−1 from t...
60 citations
TL;DR: In this paper, the backscattering of laser radiation is used to provide information on atmospheric parameters via a number of scat-graphs, which are then used for diagnostics of the atmosphere.
Abstract: Lidar systems are now widely used for diagnostics of the atmosphere. These systems employ the backscattering of laser radiation to provide information on atmospheric parameters via a number of scat...
56 citations
TL;DR: In this paper, the relative populations of the vibrational levels of the infrared night airglow spectrum using a Fourier transform spectrometer were determined from observations of the Δν ǫ = 2 and 3 sequences of the vibration rotation bands.
Abstract: Relative populations of the vibrational levels ν = 2 to ν = 9 (except ν = 5) of the hydroxyl radical have been determined from observations of the Δν = 2 and 3 sequences of the vibration–rotation bands in the infrared night airglow spectrum using a Fourier transform spectrometer. The observed line intensities were corrected for water vapour absorption using a new technique. The results indicate a population of the upper vibrational levels which is as much as a factor of two lower than that found in other studies. The observed distribution is not consistent with the atomic hydrogen ozone reaction being the sole excitation mechanism in the night airglow unless the quenching and other rates used in our model are in error.
50 citations
TL;DR: In this article, collision-induced translational-rotational spectrum of H2 has been accurately measured in the region from about 30 to 2000 cm−1 at 195 and 297 K. The difference between the experimental and theoretical values, in the order of 20%, is attributed to anisotropic overlap induction.
Abstract: The collision-induced translational–rotational spectrum of H2 has been accurately measured in the region from about 30 to 2000 cm−1 at 195 and 297 K. A very weak feature due to the hexadecapole-induced dipole, the U0(1) line, has been detected at 195 K in the region around 1622 cm−1. These spectra can be accurately represented by a simple, semi-empirical line shape. The effect of double transitions are considered and explicit expressions for these are given. Spectral integrals proportional to the zero and first moments are determined experimentally and compared with the theoretical moments computed on the basis of quadrupole induction for several potentials. The difference between the experimental and theoretical values, in the order of 20%, is attributed to anisotropic overlap induction, but the inferred magnitude of this component is strongly dependent on the assumed potential.
50 citations
TL;DR: In this article, the E1u vibration ν13 of benzene was measured on a BOMEM high-resolution Fourier transform spectrometer with a 246 cm optical path difference.
Abstract: The perpendicular band of the E1u vibration ν13 of benzene, occurring near 6.7 μm, has been measured on a BOMEM high-resolution Fourier transform spectrometer with a 246 cm optical path difference. The observed linewidth (full width at half height) of ~ 0.0048 cm−1 was reduced by deconvolution to ~ 0.0020 cm−1, which is slightly below the Doppler limit. The dense rotational structure was well resolved, and it was possible to assign over 125 subbands in the region 1466.5 to 1503 cm−1. A perturbation, identified as a third-order Jx,y-Coriolis interaction with a state located only ~ 0.055 cm−1 above the fundamental (presumably the A2u component of ν4 + 2ν20), causes distortion of the rotational structure and formation of subband heads in the low-KpQ-branches, which exhibit a striking line-like shape. The spectrum was analyzed in detail with the aid of the computer program SYMTOP for the treatment of symmetric top bands whose upper states are involved in arbitrary interactions. The Hamiltonian included, in ad...
48 citations
TL;DR: Vibration-rotation spectra of HNO (DNO) have been observed in a flow system following the reaction of hydrogen (deuterium) atoms with NO as discussed by the authors.
Abstract: Vibration–rotation spectra of HNO (DNO) have been observed in a flow system following the reaction of hydrogen (deuterium) atoms with NO. The spectra were recorded at approximately Doppler limited ...
47 citations
TL;DR: In this article, the influence of energy dependence in the electronic density of states (EDOS) on the single particle tunneling characteristics into a superconductor was studied, and the effect of the energy dependence on the tunneling behavior of a single particle was analyzed.
Abstract: We study the influence of energy dependence in the electronic density of states (EDOS) on the single particle tunneling characteristics into a superconductor. The Migdal–Eliashberg equations genera...
41 citations
TL;DR: In this paper, the effects of energy dependence in the electronic density of states (EDOS) on the electron quasiparticle properties in the normal state were studied and the Migdal-Eliashberg equations generalized to inc...
Abstract: We study the effects of energy dependence in the electronic density of states (EDOS) on the electron quasiparticle properties in the normal state. The Migdal–Eliashberg equations generalized to inc...
TL;DR: Laser-induced fluorescence (LIF) has been used to measure rotational temperatures, TR, of the aniline molecule in axis-symmetric and planar pulsed supersonic expansions of He, Ne, and Ar.
Abstract: Laser-induced fluorescence (LIF) has been used to measure rotational temperatures, TR, of the aniline molecule in axis-symmetric and planar pulsed supersonic expansions of He, Ne, and Ar. The rotat...
TL;DR: In this article, a matrix approach was used to obtain a value for the interaction matrix element (A'~/L'IC~C') = 0.88 and the limiting curve of the predissociation confirmed the previous value of the dissociation energy.
Abstract: Rotational perturbations between the C'C' and ~'1~1 states are observed in the C-X bands of BeH and BeD and in two new A-X bands of BeH (4-4 and 5-5) which have also been observed and analyzed. These perturbations are treated by a matrix approach and yield a value for the interaction matrix element (A'~/L'IC~C') = 0.88. The C-X bands analyzed involve the higher vibrational levels of the x'C' state rand allow, therefore, a substantial improvement of the ground state molecular constants to be made and a good Rydbcrg-Klein-Rees (RKR) potential energy curve to be calculated. The limiting curve of the predissociation confirms the previous value of the dissociation energy (D: = 17 426 r 100 cm-I) and indicates that a small maximum, less than 200 ern-.', could exist at r = 3.3 A in the ground state potential energy curve. Franck-Condon factors for the c'C+-x'Z' bands of BeH and BeD are also calculated.
TL;DR: In this paper, the authors presented a model potential for the H-liquid 4He interaction which is used to derive both bound and free atom wave functions and the linear H atom-ripplon coupling.
Abstract: A calculation is presented of the sticking probability for hydrogen atoms colliding with a liquid 4He surface. The calculation is based on a model potential for the H–liquid 4He interaction which is used to derive both bound and free atom wave functions and the linear H atom–ripplon coupling. Results are presented in terms of the energy and angle dependent sticking probability s(E, θ) and the thermally averaged probability s(T), and comparison is made to the experimental result s(T) = 0.035 ± 0.005 for 0.18 < T < 0.27 K.
TL;DR: Dipole oscillator strength distributions (DOSDs) have been constructed for ground state ethylene, propene, and 1-butene as discussed by the authors, using available experimental and theoretical properties.
Abstract: Dipole oscillator strength distributions (DOSDs) have been constructed for ground state ethylene, propene, and 1-butene. Each DOSD is constructed by using available experimental and theoretical pho...
TL;DR: In this paper, the output of a hybrid acoustooptic bistable device with delayed feedback is investigated, and the sequence of bifurcations is truncated by the additive electrical shot noise and the multiplicative noise due to the laser intensity fluctuations.
Abstract: The output of a hybrid acoustooptic bistable device with delayed feedback is investigated. Depending on the input intensity, such a system exhibits periodic and chaotic behaviour. Period doubling up to period-8 with the reverse Lorentz sequence is presented. The sequence of bifurcations is truncated by the additive electrical shot noise and the multiplicative noise due to the laser intensity fluctuations. Frequency locked oscillations are also presented.
TL;DR: In this paper, the halfwidths of CO vibration-rotation lines, pressure-broadened by N2, were measured in the fundamental band at −83, −148, and −180 °C, using a variable temperature absorption cell and a high resolution spectrometer.
Abstract: The halfwidths of CO vibration–rotation lines, pressure-broadened by N2 have been measured in the fundamental band at −83, −148, and −180 °C, using a variable temperature absorption cell and a high resolution spectrometer. The temperature dependence of linewidths has been calculated from the Anderson–Tsao–Curnutte theory and compared to the experimental determinations.
TL;DR: Positron lifetime and Doppler broadening experiments have been conducted in silicon which was subjected to various degrees of plastic deformation, and evidence is presented indicating the existence of the hexavacancy as mentioned in this paper.
Abstract: Positron lifetime and Doppler broadening experiments have been conducted in silicon which was subjected to various degrees of plastic deformation. With increasing plastic deformation (from 2.5 to 38%) the trapping rate per unit dislocation concentration decreased from about 8 × 1015 to 4.5 × 1015 s−1 as measured at room temperature. Two annealing stages were identified by isochronal annealing, one of which had an activation enthalpy of 3.2 to 3.8 eV as determined by isothermal annealing. Measurements in the temperature range 15 to 673 K show that the positron annihiliation parameters (lifetimes, intensities, and S-parameters) depend strongly on temperature and that the functional form of these dependencies is related to the state of annealing of the deformed samples. These results are disscussed in terms of the presence of vacancy clusters and dislocations, and evidence is presented indicating the existence of the hexavacancy.
TL;DR: In this paper, measurements of (V = electromotive force, T = temperature) on Li/LixTiS2 electrochemical cells can be used to gain information about the entropy of Lix TiS2.
Abstract: We show how measurements of (V = electromotive force, T = temperature) on Li/LixTiS2 electrochemical cells can be used to gain information about the entropy of LixTiS2. Experimental details and res...
TL;DR: In this article, a new spectrum in the region 3115-2680 A has been obtained in absorption by a flash discharge technique, and is attributed to the PO2 radical.
Abstract: A new spectrum in the region 3115–2680 A has been obtained in absorption by a flash discharge technique, and is attributed to the PO2 radical. Vibronic and K structure analyses are performed which ...
TL;DR: The approach has been to generalize the homomorphic transformation, which is a point transformation that transforms the output of a system into a space where the noise becomes independent of the signal.
Abstract: Techniques for processing of images in signal-independent additive noise are well developed. However, in practice the noise is often dependent on the signal. Some attempts to take into account the dependence of the noise on the signal have been made: our approach has been to generalize the homomorphic transformation, which is a point transformation that transforms the output of a system into a space where the noise becomes independent of the signal. Once this has been accomplished, standard techniques such as Wiener filtering should be applicable with results that are predictable. A rigorous proof of the general homomorphic transformation is given, and its accuracy is discussed. Applications to speckle noise and to film-grain noise are presented.
TL;DR: In this paper, an optical model potential approximation to the exact nucleus-nucleus multiple scattering series is used in an abrasion-ablation collision formalism to predict cross sections for relativistic Ne-20 projectile nuclei.
Abstract: Utilizing eikonal scattering theory, an optical model potential approximation to the exact nucleus-nucleus multiple scattering series is used in an abrasion-ablation collision formalism to predict abrasion cross sections for relativistic Ne-20 projectile nuclei. Excellent agreement with recent experimental abrasion results is obtained. The sensitivity of the abrasion predictions to Pauli exclusion principle correlation effects and to the assumed shape of the nuclear single-particle density distribution is also demonstrated.
TL;DR: The Ising model with nearest and next nearest neighbor antiferromagnetic interactions on the triangular lattice displays three phase transitions in different universality classes as the magnetic field is increased as discussed by the authors.
Abstract: The Ising model with nearest and next nearest neighbor antiferromagnetic interactions on the triangular lattice displays, for Jnnn/Jnn = 0.1, three phase transitions in different universality classes as the magnetic field is increased. We have studied this model using Monte Carlo and renormalization group techniques. The transition from the paramagnetic to the 2 × 1 phase (universality class of the Heisenberg model with cubic anisotropy) is found to be first order; the transition from the paramagnetic phase to the phase (universality class of the three state Potts model) is continuous; and the transition from the paramagnetic to the 2 × 2 phase (universality class of the four state Potts model) is found to change from first order to continuous as the field is increased. We have mapped out the phase diagram and determined the critical exponents for the continuous transitions. A novel technique, using a Landau-like free energy functional determined from Monte Carlo calculations, to distinguish between first...
TL;DR: In this article, the singularities, which are known to be at the heart of phase transitions and are responsible for making the thermodynamic functions of the given system nonanalytic, are explained.
Abstract: Mathematical singularities, which are known to be at the heart of phase transitions and are responsible for making the thermodynamic functions of the given system nonanalytic, are a consequence of ...
TL;DR: In this article, surface area, porosity, electrical resistivity, and Young's modulus of sintered copper and silver submicron powders with packing fractions in the range 32-54% were measured.
Abstract: Measurements of surface area, porosity, electrical resistivity, and Young's modulus of sintered copper and silver submicron powders with packing fractions in the range 32–54% are reported. These pa...
TL;DR: In this article, the 13C isotope shift of ν2 is −3.93 cm−1 and the hyperfine parameters for gas phase 13CH2 are in fairly good agreement with those determined for matrix isolated 13CD2 in earlier ESR experiments.
Abstract: Ten rotation–vibration transitions of the ν2 (bending) fundamental band of 13CH2 have been observed using the technique of CO2 laser magnetic resonance in the 880 to 945 cm−1 region. 13C substituted methylene was produced in a flow system by reacting 13CH4 or 13CH2CO with F atoms from a microwave discharge in CF4. Analysis of the spectra yields a number of molecular parameters for 13CH2. Specifically, the 13C isotope shift of ν2 is −3.93 cm−1 and the 13C Fermi contact hyperfine parameter is 238 ± 6 MHz for the ground vibrational state. The hyperfine parameters determined here for gas phase 13CH2 are in fairly good agreement with those determined for matrix isolated 13CD2 in earlier ESR experiments.
TL;DR: In this article, it was shown that the defects responsible for the short-wave and medium-wave luminescence in cuprous oxide can be created by annealing the crystal at a temperature of 1050 °C under low oxygen pressures.
Abstract: The defects responsible for the short-wave (720 nm) and medium-wave (820 nm) luminescence in cuprous oxide can be created by annealing the crystal at a temperature of 1050 °C under low oxygen pressures. The annihilation of these defects has been observed from the photoluminescence and optical absorption measurements after the crystal has been subjected to a second annealing in the temperature range of about 750 °C under a reducing atmosphere. From the photoluminescence measurements, the density of these defects is found to decrease exponentially as a function of annealing time, as manifested by the reduction in the luminescent intensity. The rate of reduction in intensity is also found to increase with annealing temperature.Because the defects responsible for the luminescence are ascribed to various forms of oxygen vacancies, we believe the decrease in luminescence is due to a reduction in the oxygen vacancies resulting from the formation of copper precipitates in the crystal. The short-wave and medium-wa...
TL;DR: In this article, two emission systems of CCl+ have been observed by the dissociative charge-transfer reaction of He+ with CCl4 in the 230 −255 and 390 −405 nm region.
Abstract: Two emission systems of CCl+ have been observed by the dissociative charge-transfer reaction of He+ with CCl4 in the 230–255 and 390–405 nm region. The former system had been detected from an electronic discharge in CCl4 vapor, though the electronic transition had not been known definitely. On the other hand, the latter system was observed for the first time in this work. By comparison with spectroscopic constants obtained by ab initio calculations, the 230–255 and 390–405 nm bands were assigned to the A1Π–X1Σ+ and a3Π1–X1Σ+ systems, respectively. From the vibrational analysis of the a−X system, the following spectroscopic constants have been determined for the new state (in cm−1):a3Π,:Te = 25 480.6 ± 1.5; ωe = 1120.3 ± 1.0; ωexe = 7.52 ± 0.14. The mechanism of charge-transfer ionization leading to the CCl+ (A, a) states was discussed in comparison with that of electron-impact ionization.
TL;DR: In this article, the authors studied the angular distribution of protons from the 170, 174, 176, 176Yb(t, p) and 180, 180, 182Hf reactions using beams of 15"MeV tritons from a tandem Van de Graaff accelerator.
Abstract: Angular distributions of protons from the 170, 174, 176Yb(t, p)172, 176, 178Yb and 178,180Hf(t, p)180, 182Hf reactions have been studied using beams of 15 MeV tritons from the McMaster University tandem Van de Graaff accelerator. The reaction products were analyzed with a magnetic spectrograph and detected with photographic emulsions. Levels up to ~2.5 MeV excitation were studied in each nuclide, with a typical overall resolution of ~15 keV (full-width half-maximum). Measurements were also made with targets of natural Yb and natural Hf, to improve the accuracy of relative strengths in each chain of isotopes, and with a target of 172Yb to facilitate the normalization of previously published data to the present results. One of the most notable features of the data is the large amount of L = 0 strength to excited Iπ = 0+ states for all cases where the residual nucleus has a neutron number N ≤ 108. The populations of these states are not explained by either the pairing rotational or vibrational models. The SU...
TL;DR: In this paper, a model that displays the essential environmental effects that influence the self-annihilation rate and hyperfine coupling constant of positronium in condensed matter is described, which is exactly solvable, is based on harmonic forces.
Abstract: A model that displays the essential environmental effects that influence the self-annihilation rate and hyperfine coupling constant of positronium in condensed matter is described. The model, which is exactly solvable, is based on harmonic forces. Ways in which the model can be extended are discussed.