bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of Unstable Flute-Like Cyclotron Modes Caused by the Presence of Suprathermal Particles in a Magnetoplasma
Authors: Teichmann J. , Andel H. W. H. Van
Published: April 2011

The stability of a cold magnetoplasma containing an isotropic distribution of suprathermal electrons or ions is studied. It is found that such a plasma is unstable for cyclotron harmonic modes for certain choices of the plasma parameters. Particle density gradients enhance the instability for modes propagating in the direction of the particle drifts. A finite plasma temperature as well as energy spreading of the suprathermal particles have a stabilizing effect on the instability.
The Spectral Response of Phosphors to Fast Ions
Authors: Hastings L. , Goh E. H. , Spenceley B. J.
Published: April 2011

The spectral distribution of the ionoluminescent response of a number of phosphors is compared to that of photoluminescence. For the single peaked phosphors, the response is the same. For a double peaked phosphor, ZnS:Ag, Cu, the response is quite different.
Penetrability Through a Double-Hump Barrier of Strutinsky Type
Authors: Leboeuf J. N. , Sharma R. C.
Published: April 2011

An expression is derived for the penetrability through Strutinsky's fission barrier by a method similar to Cramer and Nix's. Both incident and reflected waves are considered in the first well to include the prefission state of the nucleus. An approximation is introduced to obtain the amplitude of the wave transmitted out of the second hump of the barrier. The penetrability is expressed in terms of Weber's parabolic-cylinder functions.
High-Spin States in 23Na
Authors: Frank G. G. , Elliott R. V. , Spear R. H. , Kuehner J. A.
Published: April 2011

The 12C(12C,pγ)23Na reaction has been used to study the γ-ray deexcitation of levels up to Ex = 10.4 MeV in 23Na. Doppler-shift attenuation measurements yielded mean lifetimes or lifetime limits for 22 levels. Branching ratios were obtained for the 5.54, 6.11, 6.24, and 6.35 MeV levels and the major modes of decay were observed for 7 levels above Ex = 7 MeV. Angular distributions were measured for γ rays in coincidence with proton groups corresponding to the 5.54, 6.11, 6.24, 6.35, 9.04, and 10.35 MeV levels. The 6.35 MeV level is assigned a spin and parity of 9/2− and interpreted as a member of the low-lying Kπ = 1/2− band in 23Na. Levels at 9.04 and 10.35 MeV are interpreted as the 15/2+ and 13/2− members of the ground-state rotational band and Kπ = 1/2− band, respectively. The experimental γ-ray transition strengths in 23Na are compared to those predicted by the Nilsson model including band mixing. The M1 strengths are modified to account for the effects of isospin.
Evaluation of the Percus–Yevick Theory for Mixtures of Simple Liquids
Authors: Grundke E. W. , Henderson D. , Murphy R. D.
Published: April 2011

This paper reports zero-pressure excess properties of binary fluid mixtures of Lennard-Jones 6:12 molecules calculated from the Percus–Yevick (PY) theory and the energy equation. The PY theory, used this way, gives results that are in excellent agreement with simulation studies.In addition, results obtained from the compressibility equation are discussed for comparison. The geometrical structure of the mixture, as indicated by the PY pair distribution functions, is described. Error estimates are provided for the calculated excess properties.
High-Energy Levels in 13N
Authors: Measday D. F. , Hasinoff M. , Johnson D. L.
Published: April 2011

A natural carbon target was bombarded by protons in the energy range Ep = 9 to 24 MeV (Ex = 10 to 24 MeV in 13N). High-energy γ rays were detected in a NaI crystal oriented at 90° to the beam direction. Excitation functions were obtained for the 12.71 and 15.11 MeV γ rays from inelastic scattering on 12C and for capture γ rays from the reaction 12C(p, γo)13N. New structure is reported for all these reactions.
Transport Properties of the Ferromagnetic Metals. I. Cobalt
Authors: Laubitz M. J. , Matsumura T.
Published: April 2011

The thermal conductivity, electrical resistivity, and thermoelectric power of well-characterized, polycrystalline specimens of pure Co have been determined in the temperature range of 90 to 1250 K. Additionally, the measurements of the electrical resistivity have been extended to 1750 K, and the coefficient of thermal expansion measured between 300 and 770 K. The new results are compared with those previously published, and, for the low temperature h.c.p. phase, compared with predictions based on published band structure calculations. Qualitatively, the observed results agree with the predictions, particularly as far as the very unusual temperature variation of the Lorenz function is concerned; quantitative comparisons, however, are impossible, due to the lack of precision in the calculated band structures. The theoretical analysis of the results for the high temperature f.c.c. phase will be given together with that of Ni in Part II.
Structure of the Second- and Third-Order Energies of Atoms
Authors: Sharma C. S. , Rebelo I.
Published: April 2011

It is shown that expressions for the second- and third-order Hartree–Fock energies can be deduced without using the second- and third-order Hartree–Fock equations and without the help of the Hellmann–Feynman theorem. The structure of the second- and third-order Hartree–Fock and correlation energies are studied in the light of the method recently developed by Sharma and Bowtell.
Radio Aurora, Storm Sudden Commencements, and Hydromagnetic Waves
Authors: McDiarmid D. R. , McNamara A. G.
Published: April 2011

Approximately 9 years of Ottawa fixed-antenna 48 MHz auroral radar records have been examined for cases of periodically varying radio aurora following ssc's and si's. The occurrence, period, and time delay of onset of long period pulsating radio aurora (DPEl, and FPEl,) are found to be related to the amplitude of the ssc which precedes it. These relationships do not always hold for DPEl, and FPEl following si's. A discussion of the possibility of an association between the radio aurora and hydro-magnetic waves generated by the ssc or si is presented.
Polarization in Two-Body Scattering with Separable Potentials
Authors: Bhatt S. C.
Published: April 2011

From the Lippmann–Schwinger equation, we obtain a full two-body T matrix in a closed form for a rank one separable potential. Using the Wolfenstein form for the scattering matrix for the scattering of two spin-1/2 particles we obtain Wolfenstein parameters in terms of the form factors for a one term separable potential. If both incoming particles are unpolarized, we find the polarization of one of the outgoing particles to be identically zero in spite of the inclusion of tensor forces in the separable potential of rank one.
Excitation of the Ground-State Rotational Band in 28Si by Inelastic Scattering of 25.25 MeV Polarized Protons
Authors: Swiniarski R. de , Conzett H. E. , Lamontagne C. R. , Frois B. , Slobodrian R. J.
Published: April 2011

Angular distributions of the analyzing power and cross sections have been measured for the elastic and inelastic scattering of 25.25 MeV protons exciting the K = 0+ ground-state band in 28Si. Good agreement with experiment is obtained in the coupled-channels formalism on the basis of the rotational model with a quadrupole deformation β2 = −0.40 (oblate) and a hexadecapole deformation β4 = +0.15. The calculations show the great sensitivity of the experimental results to both the magnitude and sign of the quadrupole and hexadecapole deformations. Equivalent fits of the data were obtained either by keeping the deformation length of the various deformed terms of the optical potential constant (δ0 = β0R0 = βIRI = βLSRLS) or by increasing the deformation of the spin–orbit optical potential relative to the central potential by a factor of 1.5 (βLS = 1.5βcent).
64Zn(γ,n)63Zn Cross Section From 20.4 to 21.9 MeV
Authors: Bianco W. Del , Kundu S. , Boucher P.
Published: April 2011

The 64Zn(γ,n)63Zn cross section has been measured over the energy range Eγ = 20.43 to Eγ = 21.94 MeV using monochromatic γ rays from the T(p,γ)4He reaction and detecting the resulting positron activity. The γ rays were monitored by a 23 cm diameter by 23 cm long NaI crystal. The positron activity was determined by a coincidence detector consisting of two 7.6 cm diameter by 7.6 cm long NaI crystals set on the annihilation radiation photopeaks. The γ-ray energy resolution was better than 110 keV over the whole energy range. Structure, although reported by other experimenters, was not observed.
Analysis of Ultrasonic Fields by Light Diffraction
Authors: Vrba J. , Haering R. R.
Published: April 2011

It is shown how the frequency, wavelength, intensity, and propagation direction of waves present in ultrasonic wave fields may be determined by light scattering experiments. The relationship between index of refraction variations and arbitrary strain fields is developed for hexagonal crystals and explicit results valid for CdS crystals are presented.
Light Shift and Light Broadening in the 87Rb Maser
Authors: Busca G. , Têtu M. , Vanier J.
Published: April 2011

A description of measurements of light-shift and light-broadening parameters for an 87Rb maser operating between the field independent levels is reported. A parallel study of the spectral profile of theD1 pumping line is described. Comparison between the experimental results and theoretical calculations, taking into account the spatial inhomogeneity of the pumping light in the absorption cell, is presented.
Radio Auroral Measurements Near an Auroral Electrojet
Authors: Harris F. R. , Kavadas A.
Published: April 2011

Simultaneous observations of evening radio aurora and an auroral electrojet show that during the growth and expansive phases of the substorm radio aurora was present and coincident with or close to the electrojet.
Parametric Oscillations and Stability of a Periodically Charged Liquid Droplet
Authors: Ionides G. N.
Published: April 2011

The stability of an incompressible fluid droplet, carrying a time periodic electric charge, is considered. It is shown that this electrohydrodynamic problem is described by a Mathieu equation. As a result, the amplitude of the charge required to induce instability may be much smaller than in the corresponding case of a constant charge. The calculations are applicable to the dynamics of raindrops in electrified clouds.
An Idealized Model for the Band Theory of Ferromagnetism
Authors: Lee C. T.
Published: April 2011

In this idealized one-band model, we assume that the direct and exchange interactions among the electrons considered are all the same no matter what Bloch orbitals they may occupy. Using the permutation group theory, we can construct the many-electron wave functions such that they are eigenfunctions of the total spin angular momentum S, as well as of the component Sz. There will be no intraconfiguration interaction among such many-electron states, i.e., the matrix elements of the Hamiltonian between any two states derived from the same set of occupied orbitals will vanish. We will further assume that the interconfiguration interaction is negligible so that we can take the diagonal matrix elements of the Hamiltonian as good approximations to the eigenvalues. In the present paper, we will consider the simple case when the energy band is of rectangular form. Then we are able to calculate exactly the equilibrium value of S as a function of temperature. It can be shown quite clearly that the condition for ferromagnetism is V > ε ≡ Δ/M where V is the exchange energy; Δ is the band width; M is the total number of orbitals in the band. The effect of band energy is to reduce the Curie temperature, i.e., the wider the energy band, the lower the Curie temperature. The Curie temperature vanishes at V = ε. For V < ε there cannot be any spontaneous magnetization.
Measurement and Evaluation of the Activation Resonance Integral of 146Nd, 148Nd, and 150Nd
Authors: Ricabarra M. D. , Turjanski R. , Ricabarra G. H.
Published: April 2011

Values of the ratio of the reduced activition resonance integral to the thermal cross section, I′/σ0, of 146Nd, 148Nd, and 150Nd were determined relative to gold by measuring cadmium ratios. A lithium-drifted germanium gamma-ray spectrometer was used to resolve the activities of the irradiated samples. The results are: for 146Nd I′/σ0 = 1.42 ± 0.10 and with an assumed σ0 = 1.4 b, I′ = 1.99 ± 0.20 b; for 148Nd I′/σ0 = 4.22 ± 0.14 and with an assumed σ0 = 2.5 b, I′ = 10.5 ± 0.9 b; and for 150Nd I′/σ0 = 13.7 ± 0.8 and with an assumed σ0 = 1.2 b, I′ = 16.4 ± 2.8 b.The resolved and unresolved epithermal integrals of 146Nd, 148Nd, and 150Nd were calculated. Values of the spectral correction factor were also calculated, so the resonance integral could be obtained from the epithermal integral data measured in our reactor spectrum in this experiment. Epithermal integral and spectral correction factors are listed in the text.The most important result of this investigation is that the 148Nd activation reduced resonance integral is about half of the previously recommended value and consequently the radiative width for 148Nd is also about half of the previously accepted value.
The 5207 Å Band System of Glyoxal-d1 and Glyoxal-d2
Authors: Dong Ronald Y. , Ramsay D. A.
Published: April 2011

Vibrational assignments are given for absorption bands of the first triplet–singlet system of glyoxa-d1 and glyoxa-d2.
Thermal Effects on the Electromagnetic Instability in a Counterstreaming Electron Plasma
Authors: Seshadri S. R.
Published: April 2011

The thermal effects on the characteristics of the instability of a plane electromagnetic wave propagating obliquely to a counterstreaming electron plasma are investigated using a simple velocity distribution for the electrons. For all directions of the wave vector unstable waves exist for wavenumbers below a cutoff value. The velocity distribution of the electrons is found to reduce the cutoff wavenumber and the growth rate, and this reduction is seen to increase as the wave vector is further removed from the direction of the streams. In contrast to a zero-temperature plasma, the thermal effects quench the instability for all directions of the wave vector with respect to the counterstreaming plasma for wavenumbers above a certain maximum value which is inversely proportional to the average thermal velocity. Also, the dependence of the growth rate on the stream direction with respect to the wave vector is examined for various values of the wavenumber. The velocity distribution of the electrons decreases the growth rate and this inhibiting influence increases with increasing values of the wavenumber. In addition, unlike in the case of a zero-temperature plasma, the quasi-static assumption is found to be inapplicable for predicting the characteristics of the instability except for the case in which the wave vector is very nearly parallel to the direction of the streams.
Convergent Long Wavelength Expansion Method for Two-Dimensional Scattering Problems
Authors: Hill Robert Nyden , Kleinman Ralph E. , Pfaff Edwin W.
Published: April 2011

A conformal transformation is used to map the exterior of a scatterer of arbitrary shape into the exterior of a circle. This mapping replaces the problem of scattering from an awkwardly shaped scatterer in a medium of constant index of refraction (constant k2) by the problem of scattering from a circle in a medium of varying index of refraction (varying k2). The variation in the index of refraction is treated perturbatively by taking for the unperturbed problem the problem of scattering by a circle in a medium of constant index of refraction. Generally applicable bounds on the region of convergence of the perturbative solution are obtained and evaluated numerically for the case of Dirichlet boundary conditions. Error bounds on the remainder after n iterations are given. The method is illustrated by explicit calculation of the scattering from an infinite strip.
Positron–Helium Scattering Cross Sections and Phase Shifts below 19 eV
Authors: Jaduszliwer B. , Paul D. A. L.
Published: April 2011

The total cross sections for elastic scattering of positrons in the energy range from 4 to 19 eV have been measured by the method of transmission. By varying a magnetic field applied along the axis of the scattering chamber the transmitted fraction of the beam is altered, from which individual phase shifts can be extracted. s-, p-, and d-wave phase shifts are given over the entire energy range. The s-wave phase shifts are in agreement with values published by Drachman in 1968, while the p- and d-wave phase shifts are intermediate between values calculated by the same author in 1966 and 1971. The experimental results agree with those of Costello et al., and marginally with our own 1972 results, but are significantly different from those of Canter et al. We compute that the Ramsauer minimum in the diffusion cross section must be 0.04πa02 at 1.6 eV while the minimum in the total cross section is 0.11πa02 at 2.1 eV. The shoulder breadth observed in annihilation experiments is in nice agreement with what one would predict from our phase shifts.
SU(1, 3) as a Dynamical Group; Analysis of All the Discrete Representations
Authors: Kalman C. S.
Published: April 2011

A method using the most degenerate representation of SU(1, 3) as a dynamical group for the strong interactions of the spin 1/2+ baryons is extended to consider all the discrete representations. It is shown that physical conditions place very severe restrictions on the parameters characterizing such a representation.
Optical Birefringence in Solid Nitrogen
Authors: Gannon D. J. , Morrison J. A.
Published: April 2011

Quantitative measurements have been made of optical birefringence in two solid phases (α and β) of nitrogen. For the β phase (T > 35.6 °K), the observed birefringence is consistent with the structure determined by X-ray diffraction (P63/mmc) and it fixes the c/a ratio of the lattice accurately. While the measurements do not distinguish between the two structures (Pa3 and P213) that have been proposed for the α phase (T < 35.6 °K), they place a strict upper bound on the possible distortion that might arise from displacement of the nitrogen molecules from sites of cubic symmetry.
Depolarized Rayleigh Light Scattering in Molecular Gases. A Comparison between Theory and Experiment
Authors: McCourt F. R. , Rudensky T. , Moraal H.
Published: April 2011

A modification of the bulk polarization kinetic theory treatment of depolarized Rayleigh light scattering is presented and employed in calculating the half-width of the depolarized Rayleigh line as a function of density for the molecular gases n-H2, n-D2, N2, and CO2. Values of the broadening coefficient of 0.132, 0.131, 1.16, and 3.1 GHz amagat−1 have been calculated for these four gases, to be compared with the experimental values 0.106 ± 0.004, 0.141 ± 0.004, 1.5 ± 0.3, and 2.8 ± 0.3 GHz amagat−1, respectively.
s-Channel Profile Factor Model for Regge-ρ Exchange and Duality in π−p → π−Δ+(1236) and π+p → π0Δ++ (1236)
Authors: Heckman P. E. , Henzi R.
Published: April 2011

We present the results of an analysis of differential cross sections and isobar density matrix elements in isobar production π−p → π−Δ+ (1236) and π+p → π0Δ++ (1236) using an s-channel profile factor model for Regge-ρ exchange previously tested in π−p → π0n. Implications for future experiments are discussed.
Parametric Study of a Helical TEA CO2 Laser
Authors: Girard A. , Pépin H. , Vallée J. G.
Published: April 2011

We present results of a parametric study of a helical TEA CO2 laser. The output pulse energy, peak power, pulse shape, and beam divergence have been studied as functions of the capacitance, charging voltage, and gas composition. At 50 kV, with a capacitor of 0.01 μF for each element, we have obtained 3.5 MW output in a 100 ns laser pulse. This study will be of interest to those wishing to use such a device.
Stark Shifts of He I 3889, He I 4713, and He I 5016
Authors: Morris R. N. , Cooper J.
Published: April 2011

The shifts of the means of three isolated neutral helium plasma spectral lines emitted from an atmospheric plasma jet ([Formula: see text] and [Formula: see text]) were measured. Using the GBKO Stark broadening theory, first with the quasi-static assumption for the ions and then taking ion dynamic effects into account, formulas were derived and used to determine theoretically predicted shifts to be compared with the measured values under the experimental conditions. The agreement is good, and only small deviations from quasi-static behavior occurred.
A Rotational Flow Model for Spectra of Deformed Nuclei in the Rare-Earth Region
Authors: Prakash V. R. , Deshpande V. K.
Published: April 2011

The rotational flow model with a simple flow in two dimensions already proposed by Prakash et al. has been extended to include flows in three dimensions with a constant vorticity. The kinetic energy of rotations and the form of Hamiltonian thus obtained compares closely with that of the rigid rotator, but gives different expressions for the principal moments of inertia for a deformed nucleus. The Hamiltonian is quantized in the angular momentum representation. The eigenfunctions are the familiar D functions. The vorticity constant for a nonaxially symmetric nucleus is found to depend both on the deformation parameter β and the asymmetry parameter γ. However, for spherical nuclei the flow becomes irrotational and thus accounts for the absence of rotational spectra in such nuclei.Taking into account the potential energy due to centrifugal stretching phenomenologically, calculations have been done for rotational levels belonging to the first excited β-vibrational band. The results are in good agreement with the experiment for nuclei in the middle of the region 150 < A < 190. The model presented here successfully reproduces the results reported earlier.
Equations d'Etat des Systèmes à Symétries de Hooke
Authors: Dubois Jean-Guy
Published: April 2011

A cosmological but nonrelativistic generalization of the Galilean kinematic is given by the Hooke groups. We deduce, for the corresponding universes, the Hookean invariant systems state equations. We particularly study the spin 0 and the spin 1/2 cases, the Hooke analogues of the Schrödinger and Pauli equations. The classical limit, that is the Hamilton–Jacobi equation, is also considered.
A Correction to the Governor Model Moment of Inertia
Authors: Prakash V. R.
Published: April 2011

It is shown that the expression for the moment of inertia used in the governor model calculations is incorrect. A correct expression for the moment of inertia is derived from first principles and is found to differ from the earlier, approximately by a factor of 1/2. This introduces a significant correction in the calculation of the number of nucleons outside the rotationally invariant core and the possible closed shell configuration given by Trainor and Gupta.
The Band System of Propynal: Rotational Analysis of the 0–0 Band Near 4145 Å
Authors: Birss F. W. , Dong Ronald Y. , Ramsay D. A.
Published: April 2011

The 0–0 band of the [Formula: see text] system of propynal near 4145 Å has been photographed under high resolution and a rotational analysis carried out. The principal molecular constants for the ã3A″ state are (in cm−1):[Formula: see text]Altogether, 1237 lines have been assigned to transitions with ΔKa = 0. The dominant transition moment involves mixing of the ã3A″ state with higher 1A′ states.A simple magnetic rotation spectrum has been obtained and the assignments of the lines discussed.
Relationship between Pair Potentials and Liquid Structure
Authors: Ballentine L. E. , Jones J. C.
Published: April 2011

The Percus–Yevick and hypernetted chain theories are used to investigate the sensitivity of the pair potential [Formula: see text] to errors in the measured structure factor S(K) for several liquid metals and nonmetals. The linear relation between small errors, [Formula: see text], is studied by means of a generalized eigenvector analysis. Only those combinations of errors in S(K) which correspond to large eigenvalues lead to significant uncertainties in [Formula: see text]. The general form of the dominant eigenvectors was found to be the same for all liquids studied, except near the critical point. With this same exception, the following conclusions hold: Errors in S(K) for small K have by far the greatest effect on [Formula: see text]; the depth of the attractive portion of [Formula: see text] is most sensitive to errors in S(K); the repulsive core of [Formula: see text] is insensitive to errors in S(K); and the height of the main peak of S(K) has very little effect on [Formula: see text].
Excited States in 53Mn by the 53Cr(p,nγ)53Mn Reaction
Authors: Chung Woon-Hyuk , Sheppard D. M. , Olsen W. C. , Robertson B. C.
Published: April 2011

The properties of the low-lying excited states in 53Mn were studied by measuring γ-ray angular distributions and lifetimes using the 53Cr(p,nγ)53Mn reaction. Energy levels of 53Mn have been found at 0.378, 1.288, 1.440, 1.619, 2.272, 2.405, 2.572, 2.670, 2.687, 2.705, 2.872, 2.876, 2.914, 2.947, 3.005, 3.095, 3.125, 3.183, 3.193, and 3.250 MeV. The measurement of γ-ray angular distributions and yield curves together with predictions based on the compound nuclear statistical model have enabled spin assignments to be made to the following excited states in 53Mn: 1.440 MeV (11/2), 1.619 MeV (9/2), 2.572 MeV (7/2), 2.687 MeV (7/2), 2.947 MeV (9/2), 3.005 MeV (5/2). Multipole mixing ratios and branching ratios were determined for some of the observed transitions. Lifetimes of nine excited states in 53Mn have been measured using the Doppler-shift attenuation method.
The Few-Body Problem in Nonrelativistic Quantum Field Theory
Authors: Capri A. Z.
Published: April 2011

We utilize the fact that the nonrelativistic second-quantized formalism is simply a compact way of stating the n-body problem for arbitrary n, to derive the Schrödinger equations for few-body problems. This is particularly useful for models resulting from field theories in which a field is coupled to itself via another field, as in the case of nucleon–nucleon coupling via mesons. In this latter case, one obtains an effective nonlocal, energy dependent potential which itself depends on the possible states of the system.
Electric Field Dependence of Curie Temperature in Ferroelectric Crystals
Authors: Semwal B. S. , Sharma P. K.
Published: April 2011

The electric field dependence of the Curie temperature of a ferroelectric crystal in its paraelectric phase is investigated from the Silverman–Joseph Hamiltonian augmented with fourth-order phonon coordinates using the temperature dependent double-time Green's function technique. It is shown that the Curie temperature shifts to a lower value by the application of an electric field. This result agrees with the recent Raman scattering data of Worlock and Fleury for SrTiO3.
The Forbidden Rotational Spectrum of GeH4 in the Ground Vibronic State
Authors: Ozier Irving , Rosenberg Arieh
Published: April 2011

The pure rotational spectrum of the tetrahedral molecule GeH4 has been studied with a 10.6 m light-pipe absorption cell and a conventional Michelson interferometer. Fifteen lines have been observed between 50 and 130 cm−1 with a theoretical resolution of 0.5 cm−1. These lines have been identified as arising from forbidden (J → J + 1) transitions for the rotational levels J = 9–23. A detailed discussion is presented of the identification of the absorption mechanism with the distortion electric dipole moment μD produced in the ground vibronic state by centrifugal effects. Particular attention is paid to showing that the rotational transitions within the vibrational state v4 do not contribute to the observed spectrum. The theoretical problem of determining the rotational constant B0 and the scalar distortion constant DS from the data is considered. It is shown that the frequency shifts due to the fourth-rank tensor distortion interaction must be taken into account in the analysis. It has been determined that B0 = (2.696 ± 0.003) cm−1 and DS = (3.3 ± 0.6) × 10−5 cm−1. From estimates of absolute line intensities, it has been found that [Formula: see text].
On the Phase of the ρ–ω Mixing Parameter Derived from the Unitarity Relation
Authors: Gien T. T.
Published: April 2011

The phase of the ρ–ω mixing parameter is calculated in detail from the unitarity relation without considering the so-called superweak hypothesis for the ρ and ω decay. It is found that the result does not differ considerably from the one obtained previously (Gien) with the superweak hypothesis used.
Noncubic Local Structure in a Pr3+ -Doped SeOCl2:SnCl4 Solution
Authors: Watanabe A.
Published: April 2011

From a computer analysis of the fluorescence spectra of Pr3+ ions in a SeOCl2 solvent host, we show the existence of three components in the 3P0 → 3H4 transition. The small number of components suggests that each ion interacts with a local field of high symmetry. Group-theoretical considerations are shown to lead to the conclusion that the local field consists of a cubic part of tetrahedral symmetry and a residual part of D2d symmetry.
The Q Branch of the Fundamental Raman Band of the Ordered Phase of Solid Hydrogen and Deuterium
Authors: Prior William R. C. , Allin Elizabeth J.
Published: April 2011

The Raman transition ν = 0 → ν = 1, J → J has been studied in the ordered phase of solid o-H2 containing ~5% p-H2, and of solid p-D2 containing ~5% o-D2. Two new features of low intensity appear in the Q branch when the change from the disordered to the ordered structure occurs. One of the new features is sharp and is due to a vibrational excitation which is localized because, when the concentration of impurity molecules is low, the ordering of the molecules is distorted only locally about the impurity sites. The second new feature is broad and is due to simultaneous vibron–libron excitations. The frequency of the intense Q1(1) feature decreases by ~0.5 cm−1 on ordering due to an increase in the quadrupolar intermolecular interaction in the ordered phase; the Q1(0) feature is unaffected by the ordering.
Short Range Triplet Correlations in Krypton Near the Critical Point
Authors: Winfield D. J. , Egelstaff P. A.
Published: April 2011

Neutron diffraction data have been taken for two states on the 218 °K isotherm of krypton. The isothermal pressure derivative of the fluid structure factor is interpreted in terms of the triplet correlation function using an expansion due to Abe. It is concluded that three terms in Abe's expansion explain the data to a first approximation, but significant discrepancies remain.
Studies in Molecular Dynamics by Collision-Induced Infrared Absorption in H2–Rare Gas Mixtures. II. Diffusional Narrowing of Quadrupole-Induced Transitions
Authors: Mactaggart J. W. , Remigis J. De , Welsh H. L.
Published: April 2011

The profiles of the quadrupole-induced transitions (S1(0), S1(1)) of the pressure-induced fundamental infrared absorption band of hydrogen are studied in H2–Ar, H2–Kr, and H2–Xe gas mixtures up to high densities a few degrees above the critical temperature of the rare gas and in the corresponding liquid mixtures along the liquid–vapor line. The half-width δq of the transitions remains practically constant for the gas mixtures up to densities of several hundred amagat and then decreases rapidly. Values of δq for the liquid mixtures, when corrected for the temperature difference, are the same as the gas values at the same density. The narrowing of the transitions in the high-density region is interpreted in terms of the diffusional narrowing theory of Zaidi and Van Kranendonk, and is used to calculate diffusion coefficients D12 of H2 molecules in dense rare gas fluids. The results are in reasonable agreement with values of D12 previously deduced from the intercollisional interference effect in the overlap-induced components (Q1(0), Q1(1)) of the same band.
The Detection of Alpha Particles With Superconducting Tunnel Junctions
Authors: Wood G. H. , White B. L.
Published: April 2011

A superconducting thin film tunnel junction (Sn–SnO2–Sn) of total thickness 400 nm, area 7 × 10−4 cm2, and normal (4.2 K) resistance 77 m? was prepared on a glass substrate. When cooled to 1.2 K and suitably electrically and magnetically biased, the junction was bombarded with 5.1 MeV alpha particles. The resulting pulses induced in the tunnel current were observed to have amplitudes up to 19 times the r.m.s. output noise level. The possibility of utilizing this effect in charged particle spectrometry is explored.
Rotation–Vibration Coupling in Diatomic Molecules and the Factorization Method. I. Closed Form Formulas for the Vibration Intensities
Authors: Badawi M. , Bessis N. , Bessis G.
Published: April 2011

It is shown that the factorization method followed by an “accelerated" operatorial formalism or an equivalent matrix procedure leads to explicit formulas for calculating transition matrix elements. The calculation has been completely carried out for the pure vibration case of diatomic molecules, for any degree k of the dipole moment Taylor's expansion. The intuitive approximate proportionality between the radial dipole matrix element and an overlap integral is demonstrated.
Rotational Satellite Intensities and Triplet Splitting in the B3Σu− State of S2
Authors: Meyer Keith A. , Crosley David R.
Published: April 2011

Measurements have been made on the intensities of rotational satellites (ΔN ≠ ΔJ) in selectively excited fluorescence in the B–X system of S2. The satellites appear in fluorescence emitted by the ν′ = 4 level but are absent in ν′ = 3 emission. Comparison of our results with line strengths calculated according to the formulation of Tatum and Watson shows that these two adjacent vibrational levels differ in the magnitude and sign of the triplet splitting constant. A reexamination of previous spectral analyses of the B–X system confirms this variation in coupling among B-state vibrational levels.
On the Weak Ferromagnetism of Orthorhombic CuFe2S3
Authors: Townsend M. G. , Horwood J. L. , Gosselin J. R.
Published: April 2011

Orthorhombic CuFe2S3 is weakly ferromagnetic. The magnetic susceptibilities of single-crystal and polycrystalline specimens have been determined at temperatures between 78 and 500 °K. A model is presented to explain the weak ferromagnetism.
Nonlinear Damping of Standing Waves on Shallow Water
Authors: Curzon F. L. , Phillips M. G. R.
Published: April 2011

The amplitude of a standing wave on shallow water has been observed as a function of the excitation frequency (ω) in conditions where nonlinear effects are important. It is found that the peak of the normal resonance curve is flattened, due to extra damping caused by resonant, nonlinear generation of a wave having an oscillation frequency of 2ω. The experimental observations are in good agreement with the theoretical model presented in the paper.
Classification of Optical Auroral Pulsations
Authors: Thomas I. L. , Scourfield M. W. J. , Parsons N. R.
Published: April 2011

A classification scheme is proposed for optical auroral pulsations based on their occurrence with respect to the progressive phases of the auroral display together with their physical properties. The application of such a schedule to existing pulsation reports reveals a preponderance of observations of recovery phase pulsating arcs, bands, and patches obtained near the equatorward side of the auroral oval, and indicates a need for more complete observations at other latitudes and during other display phases. A greater usage of image recording techniques would also be of benefit in clarifying the role of temporal and spatial variations in auroral dynamics.
The Hexadecapole Moment of the Hydrogen Molecule
Authors: Karl Gabriel , Obryk Edward , Poll J. D.
Published: April 2011

The Δν = 0, 1 matrix elements of the hexadecapole moment of the hydrogen molecule are estimated to be 0.10ea04 and 0.034ea04 respectively.
Ultrasonic Attenuation and the Bulk Viscosity of Liquid Argon Near the Critical Point
Authors: Cowan J. A. , Ward P. W.
Published: April 2011

Ultrasonic attenuation measurements were recorded in liquid argon as a function of frequency along several isotherms between 140 and 150.2 K and at pressures from saturated vapor to 1000 p.s.i. The ratio α/f2 was found to be frequency dependent below 30 MHz and to vary as A[T,ρ]f−5/2 + B[T,ρ]. The frequency independent term, B[T,ρ], was used to calculate the bulk viscosity.
Réaction séquentielle : influence de différents paramètres
Authors: Goulard Gisèle
Published: April 2011

Given a sequential reaction at low energies A + B → C* → D + G* → D + E + F, we previously derived a cross-section formula which corresponds to the detection of two final-state particles. In this expression of σL some energy-dependent terms appear which are related to the relative motion of D–G* and E–F. In this paper, we study their influence on the absolute value of σL for the special reaction 11B + p → 3α at incident energies of 2.65 MeV and 163 keV and also the variations of σL with the parameters of α–α scattering.
Higher Order Core Polarization Contributions to the Effective Interaction in 42Ca – 42Sc
Authors: Jopko A. M. , Sprung Donald W. L.
Published: April 2011

A numerical calculation of the core polarization of the effective interaction between nucléons outside the 40Ca closed shell has been carried out, taking account of several higher order processes suggested by Kirson. These are a systematic inclusion of particle–hole scattering, self-screening of phonons, and modification of the one-particle to two-particle, one-hole vertex. These processes have the same effect as in the earlier calculation for 16O; namely, the final result is a very small net core polarization contribution to the effective interaction, which cannot explain the low-lying spectra.
Polarization Phenomena in CdTe: Preliminary Results
Authors: Malm H. L. , Martini M.
Published: April 2011

Nuclear radiation spectrometers, made from semi-insulating CdTe chlorine doped and grown by the travelling heater method, show a gradual degradation in performance. The pulse height for all nuclear radiations and the γ-ray efficiency both decrease with time after the collection voltage is applied. A model is outlined in which this polarization behavior is attributed to the slow detrapping of holes (τD ~ 103 s) from deep acceptors of density ~6 × 1011/cm3.
Resonance Effects in Slotted Spherical Antennas Coated with Homogeneous Materials
Authors: Shafai L. , Chugh R. K.
Published: April 2011

Radiation from a perfectly conducting slotted sphere coated with a homogeneous material is investigated. It is found that for some values of the coating thickness certain modes become resonant, which greatly enhance the radiated power and affect the radiation field. The enhancement in the radiated power, however, depends on the loss tangent of the coating material and reduces rapidly as the loss tangent increases.
Nernst–Ettingshausen Effects in GaxIn1–xAs alloys
Authors: Demars Denis J. E. , Woolley John C.
Published: April 2011

Room temperature measurements of longitudinal and transverse Nernst–Ettingshausen coefficients [Formula: see text] have been made on samples of GaxIn1–xAs alloys for a range of magnetic fields (B) up to 3.2 Wb/m2. Previous theoretical expressions for the values of these coefficients have been extended to the case of electrons in a single Kane band, and hence expressions for [Formula: see text] and [Formula: see text] obtained in terms of B, the bottom of the band effective mass m0*, and the scattering coefficient s. Fitting of these expressions to the experimental data thus has given values of m0* and s for each alloy sample. The values of m0* are found to be in good agreement with those obtained previously from plasma reflectance work, while the values of s indicate that over most of the alloy range polar optical scattering is predominant, but that in the range 0.4 < x < 0.7, alloy scattering may also have some contribution.
The Factorization Method and the Electromagnetic Giant Dipole Resonance
Authors: Goulard B. , Joseph J.
Published: April 2011

The factorization method is applied to two specific nuclei, 16O and 40Ca. It is found that the convergence of the Born series involved may depend crucially on the explicit consideration of continuum–continuum coupling effects even in the absence of single-particle resonances.
Multiple-Scattering Resonances Between Parallel Conducting Cylinders
Authors: Howarth B. A.
Published: April 2011

The results of numerical computations on the scattering of TM waves by two and three parallel conducting cylinders are described. Measurements of the diffracted field behind two 1.0λ, diameter conducting circular cylinders are compared with the predictions of approximate and exact formulations of the multiple scattering equations obtained through the multipole induction formalism. A feature of the experimental results is the occurrence of a null pair in the near field behind the array. These field singularities are also predicted by the exact formulation and are apparently a manifestation of multiple-scattering resonance. Polar diagrams of the currents induced on the surfaces of the cylindrical scatterers are presented for several sets of parameters. These diagrams show the occurrence of a resonant multiple-scattering phenomenon at critical values of cylinder separation under broadside illumination of the array. Calculations also indicate that with this illumination the forward scattering cross section of a two-cylinder array should display a characteristic maximum at a multiple-scattering resonance. Analogous resonant phenomena for the case of end-on illumination were not obtained and an explanation for this is proposed. A suggestion for the application of this resonance phenomenon is incidentally advanced, and it is also shown that the multipole induction formalism may be extended to scattering by noncircular boundaries.
Thermal Neutron Activation Cross Sections and Resonance Integrals of 94Zr and 96Zr
Authors: Santry D. C. , Werner R. D.
Published: April 2011

The activation method was used to determine thermal neutron activation cross sections, σ0, and resonance integrals, RI. Values obtained were σ0 = 47.5 ± 2.4 mb, RI = 218 ± 10 mb for 94Zr and σ0 = 22.9 ± 1.0 mb, RI = 5.20 ± 0.54 b for 96Zr. Calculations were based on the Westcott convention and the known cross sections for the 59Co and 197Au neutron flux monitors. Measurements confirmed the existence of a p-wave neutron resonance capture for 96Zr. The half-life of 97Zr was measured as 16.90 ± 0.05 h.
Spectre d'émission de la molécule PO: Transitions C′2Δ–X2Πr et C2Σ−–X2Πr de P16O et P18O
Authors: Prudhomme J. C. , Larzillière M. , Couet C.
Published: April 2011

The rotational analysis of 11 bands of the C′–X2Πr system is carried out and has allowed the study of vibrational levels of the C′ state: 1, 2, 3, 4 for P16O and 0, 2, 3, 4 for P18O. The nature of the C′ state is confirmed as a 2Δ state. New molecular constants are proposed.The analysis of the fine structure of 4 bands of the C2Σ−–X2Πr transition of P18O shows that the lowest vibrational level of the C state, which has been characterized previously for P16O, is the level ν = 1. The molecular constants of this state have been modified on account of the new identification.The fine doubling of the X2Π, C′2Δ, and C2Σ− are discussed.
On the Intramolecular Quadrupole Mechanism of Nuclear Magnetic Relaxation in the Gas Phase
Authors: Sanctuary B. C.
Published: April 2011

By use of a nuclear quadrupole intramolecular mechanism, expressions are obtained for the relaxation rates for both ortho and para X2 molecules which have nuclear spins I1 > 1/2. It is found, except for I1 = 1, that as a result of the nuclear spin weightings the two species relax with different rates, even at temperatures high enough so that the rotational averages are approximately equal.
Damping of Plasma Column Resonances by Electron Density Fluctuations
Authors: Parbhakar Kanwal J. , Gregory B.C.
Published: April 2011

Random fluctuations of the electron density can considerably influence the shape of the resonance curve exhibited by a plasma column. The fluctuations affect the resonances in a different way, depending on the order of the resonance considered. For the main resonance both the amplitude and the half-width change appreciably; however, the resonance amplitude is more sensitive to low level density fluctuations than the half-width. The first Tonks–Dattner resonance half-width remains practically constant, but the resonance amplitude decreases with increase in the level of density fluctuations. The main resonance interaction with the density fluctuations is also computed theoretically for a plasma column inserted in a wave guide, excited in the TE10 mode, assuming that the plasma behaves as a dielectric medium. The results are in good agreement with the experiment.
Crystal Dynamics of Rubidium. II. Anharmonic Calculations of the Phonon Self-Energy and the Heat Capacity
Authors: Copley J. R. D.
Published: April 2011

We have made anharmonic calculations of phonon frequency shifts and widths, the thermal strain, and the lattice heat capacity for solid rubidium. The calculations were performed using an interatomic potential derived from the work of Price, Singwi, and Tosi. The calculated shifts are in reasonable agreement with experiment, except in the case of the Σ4 transverse branch in the [ζζ0] direction, where there are definite indications that the calculation disagrees with experiment. The calculated thermal strain is ~15% too high at intermediate temperatures. On the other hand, the calculated anharmonic contributions to the heat capacity are in good agreement with experiment at intermediate temperatures, but are 10 to 20% too low near the melting temperature. The anharmonic contributions are sensitive to the third and fourth derivatives of the potential, owing to the large degree of cancellation between the cubic and quartic terms. Furthermore there is evidence that higher order anharmonic terms may be significant.
Constitutive Relations and Subsidiary Conditions in the Eikonal Approximation
Authors: Gelman Harry
Published: April 2011

The eikonal approximation is considered for propagation in an inhomogeneous, time-dependent, anisotropic environment. The usual eikonal analysis is generalized to take into account constitutive relations which contain space and time derivatives of the field quantities. The field equations are obtained for all orders of eikonal approximation. These consist of homogeneous equations for the zeroth-order, and recursion relations which connect arbitrary consecutive higher orders of approximation. An apparent inconsistency between the zeroth-order equations and the higher order ones is avoided by the development of a set of subsidiary conditions on the field approximations. The lowest order condition in this set is considered in detail, and a general relation is derived between a certain vector quantity appearing in this condition, and the tangent vector to a ray path. For an environment which is stationary and free of spatial dispersion, this relation is shown to have, as one of its consequences, a new normalization condition for the zeroth-order fields in anisotropic propagation. The relation is applied to propagation in a cold magnetoplasma, and a number of results in ionospheric propagation are recovered and extended.
The Dependence of Electronic Stopping Cross Section of 42K on Different Target Materials
Authors: Whitton J. L.
Published: April 2011

Measurement of the maximum range of 55 keV 42K along the [Formula: see text] directions of b.c.c. metals and [Formula: see text] directions of f.c.c. metals shows that the electronic stopping cross section differs by a factor of ~ 5 between the two channels. This difference is considered due to the different electronic configurations of the lattice atoms and is thus analogous to the oscillations in electronic stopping cross section seen previously for various ions in silicon, gold, and tungsten.