Showing papers in "Canadian Journal of Physics in 1974"
TL;DR: In this article, the behavior of a model kinetic equation used for describing the density fluctuation spectrum in molecular gases was analyzed in detail in the kinetic regime, in the case of molecular gases.
Abstract: We analyze in detail, in the kinetic regime, the behavior of a model kinetic equation previously used by us for the description of the density fluctuation spectrum in molecular gases. We find that ...
295 citations
TL;DR: This article analyzed long-range RKR turning points to determine inverse-power potential coefficients and showed that the inverse power potential coefficients have always required an implicit assumption about the relative magnitudes of higher-power coeffi...
Abstract: Methods of analyzing long-range RKR turning points to determine inverse-power potential coefficients have always required an implicit assumption about the relative magnitudes of higher-power coeffi...
128 citations
TL;DR: The infrared absorption spectrum of diimide (N2H2) in the 3.2μm region has been reexamined at higher resolution than previously, and that of dideuterodiimide at 4.3μm has been recorded for...
Abstract: The infrared absorption spectrum of diimide (N2H2) in the 3.2 μm region has been reexamined at higher resolution than previously, and that of dideuterodiimide (N2D2) at 4.3 μm has been recorded for...
88 citations
TL;DR: In this article, the problem of electromagnetic Gaussian beam scattering from a planar interface separating two lossless dielectric media is considered, and the reflected and transmitted beams are obtained using the Fresnel approximation, and a Taylor series expansion of the reflection and transmission coefficients, for both polarizations.
Abstract: The problem of electromagnetic Gaussian beam scattering from a planar interface separating two lossless dielectric media is considered. Employing a modal plane wave expansion and the continuity of the fields across the boundary, the reflected and transmitted beams are obtained using the Fresnel approximation, and a Taylor series expansion of the reflection and transmission coefficients, for both polarizations. Particular emphasis is given to the beam shift of both the reflected and refracted beams, the change in width of the transmitted beam, and the behavior at polarizing incidence.
79 citations
TL;DR: In this paper, the ν4 vibration-rotation bands of benzene and benzene-d6 have been recorded with high resolution and spectroscopic constants for both vibrational states have been calculated Assuming D6h symmetry for the molecules the bond lengths have been determined from the ground state rotational constants of the two isotopic molecules.
Abstract: The ν4 vibration–rotation bands of benzene and benzene-d6 have been recorded with high resolution The K = 0 subbands have been analyzed and spectroscopic constants for both vibrational states have been calculated Assuming D6h symmetry for the molecules the bond lengths have been determined from the ground state rotational constants of the two isotopic molecules The values obtained are: r0(C—C) = 13964 ± 002 pm and r0(C—H) = 10831 ± 013 pm
79 citations
TL;DR: In this paper, the emission features included in the analysis were the N2 first and second positive, Vegard-Kaplan, and infrared afterglow systems, the N 2+ first negative and Meinel systems, O2+ first positive, the O2 atmospheric system, the OH night airglow system, and the atomic line emissions, and a residual emission which was represented by a continuum.
Abstract: Quantitative spectra of medium intensity aurora in the 4500 to 8900 A region at a slit width of about 10 A are presented. By comparison with synthetically generated spectra the relative intensities of the prominent emission features have been determined, and a number of emissions of unknown origin have been identified. The emission features included in the analysis were the N2 first and second positive, Vegard–Kaplan, and infrared afterglow systems, the N2+ first negative and Meinel systems, the O2+ first negative system, the O2 atmospheric system, the OH night airglow system, the atomic line emissions, and a residual emission which was represented by a continuum. Due to the broad spectral coverage it was possible to obtain fairly complete information on the vibrational development of the brighter band systems. A number of new identifications of spectral features has led to the conclusion that in the O2 atmospheric system, bands with ν′ > 2 exist contrary to previous beliefs.
77 citations
TL;DR: In this article, the authors measured positron lifetimes in cold worked copper samples and showed that positron trapping by dislocations can be demonstrated in the case of cold-worked copper.
Abstract: Measurements of positron lifetimes in cold worked copper samples show clearly positron trapping by dislocations. The copper crystals were deformed under conditions that would lead to known densitie...
77 citations
TL;DR: In this article, an account of the classic theory of the Jahn-Teller effect for octahedral complexes is given, and an account is given of Lie groups and their relevance to the F+ center in CaO.
Abstract: After an introduction to the classic theory of the Jahn–Teller effect for octahedral complexes, an account is given of Lie groups and their relevance to the F+ center in CaO. The coincidence of the three-fold and two-fold vibrational modes (both of angular frequency ω) leads to a study of U5 and R5, the unitary and rotation groups in five dimensions. The language of second quantization is used to describe the weight spaces and branching rules. Pairs of annihilation and creation operators for phonons are coupled to zero angular momentum and used as the generators of the noncompact group O(2, 1). This facilitates the evaluation of matrix elements of V, the interaction that couples the oscillations of the octahedral complex to the electron in its interior. Glauber states are used near the strong Jahn–Teller limit, corresponding to . The possible extension of the analysis to incorporate the breathing mode is outlined. Correspondences with problems in nuclear physics are mentioned.
73 citations
TL;DR: In this paper, the beam foil studies of oxygen below 2000 A were extended and clarified, and a brief discussion of the dependence on Z−1 of the f values for transitions of the type 1s22s22pn−1s 22s2pn+1 along sequences isoelectronic with B I, C I, and N I.
Abstract: We have extended and clarified previous beam foil studies of oxygen below 2000 A. Mean lives are presented for 63 transitions for the ions O I–O VI, which provide clarification or confirmation of their values for 36 levels, and first measurements of the mean lives of 5 others. Comparison is made with recent results from a variety of experimental and theoretical techniques and, in particular, good agreement is generally found with the nonclosed shell many electron theory of Nicolaides and Sinanoglu. A brief discussion is given of the dependence on Z−1 of the f values for transitions of the type 1s22s22pn–1s22s2pn+1 along sequences isoelectronic with B I, C I, and N I. The 3P–3P0 and 3P–3S0 transitions along the C I sequence are presented in detail.
71 citations
TL;DR: In this article, the Van der Waals complex (H2) has been obtained with greatly improved resolution, and analogous spectra of (D2)2 and H2-D2 have been observed with an absorption path of 110m in a multiple traversal cell at temperatures between 16 and 21
Abstract: Spectra due to the Van der Waals complex (H2)2 have been obtained with greatly improved resolution, and analogous spectra of (D2)2 and H2–D2 have been observed. The experiments were conducted with an absorption path of 110 m in a multiple traversal cell at temperatures between 16 and 21 K. The spectra are manifested as fine structure accompanying the single and double H2 (or D2) transitions in the hydrogen (or deuterium) collision induced fundamental band. The observed structure for (H2)2 and H2–D2 can be unambiguously assigned to rotational transitions of the complex governed by the selection rule Δl = ± 1, ± 3, where l is the rotational quantum number of the complex. A detailed analysis must include anisotropic force effects, and is not given here. The spectrum of (D2)2 is complicated, not only by anisotropic force effects, but also by mutual perturbations between the rotational levels of the upper states of corresponding single and double D2 transitions; for this reason, the assignments suggested are s...
70 citations
TL;DR: In this article, it is shown that the electronic correlation functions can be extracted, in principle, by combining X-ray, neutron, and electron scattering data, though the smallness of the differences between the normalized data makes this difficult to do at present.
Abstract: Recent work on the theory of liquid metals has involved correlation functions for the ion–electron density and the electron–electron density. The experimental determination of these functions is discussed for a general homonuclear fluid. It is shown that the electronic correlation functions may be extracted, in principle, by combining X-ray, neutron, and electron scattering data, though the smallness of the differences between the normalized data makes this difficult to do at present. After reviewing the published scattering data, we conclude that the most useful procedure is to compare scattered intensities at a significant reference point, namely the principal maximum of the liquid structure factor. X-ray and neutron data are presented for liquified rare gases, molecular liquids, and liquid metals, and their averages considered. Systematic differences are found between these groups, which prompt the conclusion that electrons in molecular liquids are delocalized by chemical bonding, but that the conducti...
TL;DR: In this article, a rotational analysis of the three longest wavelength bands observable in the SO2 system was carried out and it was shown that they are type C bands, and that the approximate upper state geometric structure of the molecule is r(S O) = 1.53
Abstract: Rotational analyses have been carried out for the three longest wavelength bands observable in the '2900 A system' of SO2 (at 3340, 3359, and 3395 A). Although the bands are perturbed quite severely it has been possible to prove that they are type C bands, and that the approximate upper state geometric structure of the molecule is r(S—O) = 1.53 A, . Comparison with the theoretical calculations of Hillier and Saunders now leaves little doubt that the upper electronic state is the π → π* 1A2 state, appearing in absorption by Herzberg–Teller mixing through Q3′(b2), as recently proposed by Dixon and Halle. A vibrational numbering for these bands is given, which is consistent with the inertial defect obtained from the rotational analysis, and with recent isotope data published by Brand and Nanes: the 3395 A band appears to be 031–000, and the electronic origin falls near 27 930 cm−1.
TL;DR: In this article, a method of obtaining the magnetic properties of the random mixture of plural kinds of magnetic atoms (including nonmagnetic atoms) in both the site and the bond problems is presented.
Abstract: A method of obtaining the magnetic properties of the random mixture of plural kinds of magnetic atoms (including nonmagnetic atoms) in both the site and the bond problems is presented. The specific heats and the susceptibilities of the one-dimensional binary mixture and the binary Bethe lattice are exactly given. The phase transitions of both the Bethe lattice and the ordinary two- and three-dimensional lattices are also discussed. It is shown that the phase boundary of an ordinary binary mixture in the site problem is rather similar to that in the bond problem when JAAJBB > 0 and JαJβ > 0, while they are quite different when JAAJBB < 0 and JαJβ < 0. In the latter case, the two critical lines of ordinary lattice, on which the uniform or the staggered susceptibility diverges, cross at some value of concentration of magnetic atoms, while they are separated by the paramagnetic phase in the bond problem. The experimental result for (MnxCr1−x)Sb is similar to the former and that for Co(SxSe1−x)2 is similar to ...
TL;DR: In this article, a general functional Taylor expansion of the Helmholtz free energy and radial distribution function is derived for fluids and fluid mixtures, in a form convenient for n-merical computation.
Abstract: A general functional Taylor expansion of the Helmholtz free energy and radial distribution function is derived for fluids and fluid mixtures. This gives rise to some known results for partic~llar choices of expansion functional. The res~~lts are presented in a form convenient for n~~merical computation, and son~ecalc~~latio ns ofg(r) for the fl~~id with potential ~r(r.) = 4~(cr/r)'~ are presented. It is s~~ggested that the present formalisni may be useful for niolec~~les with nonspherical pair potentials, and sollie new res~~lts are obtained for mixt~~res of s~~ch n~olecules. On a obten~~ un dtveloppement de Taylor general pour I'tnergie libre de Helmholtz et la fonction cle clistribution radiale d'un fl~~ide OLI d'~~n melange de fluides. Certains res~rltats connus peuvent etre retro~~ves si on choisit convenablement les fonctions ~~tiliskes dans le developpement. Les rcs~~ltats sont presentesso~~s Llne fornie appropriee aux calc~~ls n~~nieriques, et certains calculs sont etTectivement prcsentes pour le cas d'un fluide oil le potentiel est de la forrne r~(r) = ~E((s/I.)". On suggere que ce formalisme po~~rrait &tre tile dans le cas de molec~lles ayant des potentiels de paires non spheriques, et on obtient quelq~~es resultats nouveaux POLK des melanges de rnoltc~~les de ce type. [Traduit par le journal]
TL;DR: A Philips E.M. 300 electron microscope operating in the dark field high resolution mode has been used to study the size dependence of the melting points of individual particles of indium as discussed by the authors.
Abstract: A Philips E.M. 300 electron microscope operating in the dark field high resolution mode has been used to study the size dependence of the melting points of individual particles of indium. The strai...
TL;DR: In this paper, collision induced transitions between rotational levels of methanol have been investigated by steady state microwave double resonance, in order to study collisional excitation mechanisms for methanoline in the interstellar medium.
Abstract: Collision induced transitions between rotational levels of methanol have been investigated by steady state microwave double resonance, in order to study collisional excitation mechanisms for methanol in the interstellar medium. Experiments are described on pure CH3OH and on dilute mixtures of CH3OH with excess He and H2, for various four level systems of astrophysical interest. For pure CH3OH, the results are qualitatively consistent with dipolar selection rules, ΔJ = 0, ± 1 and Δk = 0, ± 1, but certain aspects of the quantitative analysis are unexplained. For collisions of CH3OH with either He or H2, the collisional transition rates decrease relatively slowly with ΔJ. In the collisions with He, parallel Δk = 0 collisional transitions occur about four times more frequently than perpendicular Δk = ± 1 transitions, whereas in collisions with normal H2, Δk = 0 transitions are approximately twice as frequent as Δk = + 1 transitions.
TL;DR: The Hall coefficient, magnetoresistance, and thermoelectric power of several specimens of NbSe2 have been measured as a function of temperature for various crystal orientations.
Abstract: The Hall coefficient, magnetoresistance, and thermoelectric power of several specimens of NbSe2 have been measured as a function of temperature for various crystal orientations. A range of behaviou...
TL;DR: In this paper, the (0, 1) and (1, 2) bands of PH and PD have been photographed in emission, under high resolution, and the 3Π and 3Σ states fine structure has been interpreted by a simple model, which includes spin-spin, and second-order spin-orbit interactions and also centrifugal distortion effects both on rotational and spinorbit coupling parameters.
Abstract: PH and PD radicals have been produced in a Schuler type discharge through PH3 and PD3. Besides the already known (0–0) bands of PH and PD, new bands, namely the (0–1) band of PH and the (1–0) and (1–1) bands of PD have been photographed in emission, under high resolution. Rotational analyses have been performed for these six bands and also for the (1–0) band of PH analyzed earlier by Legay in absorption. The 3Π and 3Σ states fine structure has been interpreted by a simple model, which includes spin–spin, and second-order spin–orbit interactions and also centrifugal distortion effects both on rotational and spin–orbit coupling parameters. The ν dependence of the different molecular parameters has been examined and interpreted where possible.
TL;DR: In this article, the beamfoil technique was used to measure radiative mean lives for 41 levels in N I −N V within the wavelength range 374 to 2064 A. The agreement for lines of higher stages of ionization was very good.
Abstract: Using the beam-foil technique, we have measured radiative mean lives for 41 levels in N I–N V within the wavelength range 374 to 2064 A. In some cases we deduce experimental absorption oscillator strengths for comparison with recent theoretical calculations of Nicolaides, who used the 'Non-closed shell many electron theory' of Oksuz and Sinanoglu. The agreement for lines of higher stages of ionization is very good.
TL;DR: In this paper, the problem of the single particle potential U in isospin and spin polarized nuclear matter, i.e. in nuclear matter with neutron excess and nonvanishing spin, is treated within the frame of the K matrix theory.
Abstract: The problem of the single particle potential U in isospin and spin polarized nuclear matter, i.e. in nuclear matter with neutron excess and nonvanishing spin, is treated within the frame of the K matrix theory. General expressions for the isospin, spin, and spin–isospin parts of U, Uτ, Uσ, and Uστare obtained with the help of K matrices which depend on two Fermi momenta. The σ and στ parts have scalar and tensor components: Uσs and Uσt, and Uστ,s and Uστ,t These general expressions are specialized for nucleons at the Fermi surface. With suitable approximations, numerical values for Uτ(kF), Uσs(kF), and Uστ,s(kF) are obtained for the Brueckner–Gammel–Thaler and the Reid soft core nucleon–nucleon interactions. The tensor components, Uστ and Uστ,t, are estimated to be much smaller than the corresponding scalar components. The rearrangement effects turn out to be very important. At higher nucleon energies the τ, σ, and στ parts of U are calculated in the phase shift approximation with the Yale and Livermore p...
TL;DR: In this article, the absorption spectrum of D2 at high resolution (0.254 A/mm) was studied in the region 1100 to 840 A. The three band systems B1Σu+
Abstract: The absorption spectrum of D2 has been studied in absorption at high resolution (0.254 A/mm) in the region 1100 to 840 A. The three band systems B1Σu+ ← X1Σg+ (Lyman bands), B′ 1Σu+ ← X1Σg+ and C1Π...
TL;DR: In this paper, the Hall effect and resistivity as well as thermoelectric power in the temperature range 300-450 K were measured in terms of a sigmoid function.
Abstract: We have made measurements of the Hall effect and resistivity as well as of thermoelectric power in the temperature range 300–450 K. The results of these measurements are interpreted in terms of a s...
TL;DR: In this article, the path integral method is used to obtain an expression involving a sum over the complete set of solutions for the effective trial Hamiltonian, for the ground state energy of the bound polaron.
Abstract: The path integral method is used to obtain an expression, involving a sum over the complete set of solutions for the effective trial Hamiltonian, for the ground state energy of the bound polaron. T...
TL;DR: In this article, the carbon-carbon correlation function was analyzed for carbon disulfide and liquid carbon diselenide and it was shown that the parallel molecular configuration is more probable in CSe2 than the T configuration expected from molecular quadrupole interactions.
Abstract: Neutron diffraction structure factors for liquid carbon disulfide and liquid carbon diselenide have been measured and are analyzed to determine molecular correlation functions using the methods developed by Egelstaff, Page, and Powles. This analysis shows that the parallel molecular configuration is more probable in CSe2 than the T configuration expected from molecular quadrupole interactions. In CS2 the data are related to the carbon–carbon correlation function, which is shown to be similar to that for monatomic liquids.
TL;DR: In this paper, an empirical relationship between sound velocity and surface tension was tested and found to hold well for the alkaline earth metals, and simple model calculations of the compressibilities at the melting points were found to be in disagreement with the experimental values.
Abstract: Ultrasonic velocity measurements have been made on liquid Mg, Ca, Sr, and Ba to temperatures ~300 °C above the melting points. An empirical relationship between the sound velocity and surface tension is tested and found to hold well for the alkaline earth metals. Simple model calculations of the compressibilities at the melting points are found to be in disagreement with the experimental values.
TL;DR: In this paper, a LoSurdo discharge was used to apply electric fields of up to 290kV/cm to a mixture of cyanogen and hydrogen, and to ammonia, permitting the observation of Stark effects in the optical spectra of the CH and NH molecules, respectively.
Abstract: A LoSurdo discharge was used to apply electric fields of up to 290 kV/cm to a mixture of cyanogen and hydrogen, and to ammonia, permitting the observation of Stark effects in the optical spectra of the CH and NH molecules, respectively. These experiments yielded the following values of the molecular electric dipole moment in the ground vibrational states: μ(CH, A2Δ) = 0.887 ± 0.045 D, and μ(NH, X3Σ) = 1.389 ± 0.075 D. A table of experimental and theoretical dipole moments of first-row hydrides is included.
TL;DR: In this article, a strong absorption band of OH has been observed near 1221 A. This absorption band will give interstellar absorption lines of OH at 1221.166, 1222.071, and 12.524
Abstract: A strong absorption band of OH has been observed near 1221 A. From the analysis of high resolution spectra, it has been determined that the upper state is a 2Σ− Rydberg state and the constants of the OH and the corresponding OD state have been obtained. It is shown that the new absorption band will give interstellar absorption lines of OH at 1221.166, 1222.071, and 1222.524 A. New constants have also been determined for the A2Σ+ and X2Π states of OD.
TL;DR: In this article, a doubly infinite set of linear equations for the currents excited on the pair of planar wire grids by a plane wave of arbitrary polarization is derived, and the equations can be solved by perturbation if the two planar arrays are sufficiently separated or by truncation and matrix inversion otherwise.
Abstract: A doubly infinite set of linear equations is derived for the currents excited on the pair of planar wire grids by a plane wave of arbitrary polarization. The equations can be solved by perturbation if the two planar arrays are sufficiently separated or by truncation and matrix inversion otherwise. The transmission coefficients are derived including the cross-polarized components, and numerical results are presented to illustrate the effects of various parameters.
TL;DR: In this article, the coherence narrowing and collision broadening of the 5s5p1P1 level of strontium have been studied and the natural lifetime of this level has been determined to be 4.68
Abstract: Coherence narrowing and collision broadening of the 5s5p1P1 level of strontium have been studied. The natural lifetime of this level has been determined to be 4.68 ± 0.10 ns. The oscillator strengt...
TL;DR: In this article, the stellar spectrum of certain N type stars in the blue-green region has been observed in the laboratory in absorption using the flash discharge technique, and it has been interpreted as a 1Π← 1Σ transition of the linear Si-C-C molecule.
Abstract: The stellar spectrum of certain N type stars in the blue–green region has been observed in the laboratory in absorption using the flash discharge technique. It has been interpreted as a 1Π ← 1Σ transition of the linear Si–C–C molecule. A new vibrational analysis has been proposed, which yields the following fundamental frequencies in cm−1. The 1Π state shows a small Renner splitting (eω2 = 3.3 cm−1). In addition, 001 and 040 levels are shown to perturb each other due to a Fermi resonance.