bluuebunny/crossref_metadata_2025 huggingface dataset:
A Rigorous Application of the Collective Model to Some Rare Earth Nuclei
Authors: Hird B. , Huang K. H.
Published: April 2011

The collective model of an odd neutron in an axially symmetric deformed Woods–Saxon potential, coupled to a rotating core, and containing the full RPC and pairing corrections has been used to predict the full low lying rotational band spectrum of the nuclei with N = 91 to 97. Only three adjustable parameters were used in each nucleus to fit the complete spectrum. It was possible in several nuclei to obtain the correct level sequence and in most to confirm level assignments, and the adjusted parameters were in good agreement with accepted values. However, the accuracy of this method is insufficient, in most nuclei, to provide reliable predictions for as yet unidentified bands. The lack of good overall agreements in the low lying spectra of these nuclei confirms that the core shape parameters do change from one band to another.
On the Validity of the Navier–Stokes Relation in a Shock Wave
Authors: Elliott J. P.
Published: April 2011

It is shown that the Navier–Stokes relation is not valid in a shock wave, and that the shock thickness is greater than predicted by the Navier–Stokes equations.
Symmetries of Neutral Weak Currents
Authors: Cordes J. G. , Kiang D. , Tsai S. Y.
Published: April 2011

The U2 × U2 and D symmetries of the leptonic weak interaction are extended, within the framework of the quartet–quark model, so as to include the hadronic weak interaction. The total weak current satisfies a lepton–quark symmetry. Application of these symmetries to the neutral current weak interaction restricts the current to be composed only of vector and axial vector pieces, and also restricts the symmetry properties of its (V−A) part. Experimental implications of these symmetries in various neutrino reactions are investigated. There are some ambiguities as regards the (V+A) part of the neutral current, which may, however, be resolved soon if more experimental data become available.
Photoneutron Angular Distributions for 4He
Authors: Irish J. D. , Johnson R. G. , Berman B. L. , Thomas B. J. , McNeill K. G. , Jury J. W.
Published: April 2011

Differential cross sections for the reaction 4He(γ, n)3He have been measured at laboratory angles of 53°, 68°, 83°, 98°, 128°, and 143° for excitation energies between 22 and 32 MeV by the photoneutron time of flight technique. The photoneutron spectra were used to obtain the angular distribution coefficients in the Legendre series expansion for the differential photoneutron cross sections. Analysis of these coefficients indicates that the photodisintegration process in this nucleus, while dominated by E1 photon absorption followed by channel spin zero (no spin flip) p wave neutron emission, is affected by E1 channel spin one and E2 contributions. In the higher energy region (E > 27 MeV), the amount of E2 absorption observed was ~6% of the total and is dominated by the channel spin one E2 matrix element. The total cross section obtained from the measured differential cross sections yields a value of σ(γ, p)/σ(γ, n) near unity, in agreement with a calculation of this ratio which requires no charge symmetry breaking component of the nuclear force.
Electric Field Studies of the X Band Microwave Transitions in D2O
Authors: Dagg I. R. , Reesor G. E. , Wong A. M. C.
Published: April 2011

Measurements of the zero field absorption lines and of the Stark splittings in D2O are reported for the 313 ← 220 and the 441 ← 532 transitions which are at frequencies near 10.9 GHz. Calculations of the hyperfine interactions using recent data describe well the absorption profiles of the zero field lines and are the basis for choosing the extrapolated zero field frequencies for the Stark frequency shifts. The dependence of the shifts on the square of the field strength is recalculated using recent data and compared with the experimental results. The dependence of the Stark shift on the fourth power of the field strength is also measured. The value of the dipole moment of D2O is found to be 1.857 ± 0.003 D for the 3 ← 2 transition and 1.884 ± 0.006 D for the 4 ← 5 transition, which indicates that there is a small dependence of the dipole moment on the rotational state for this molecule. The dependence is found to be greater than that reported previously.
Spin Susceptibility of Exchange Enhanced Metallic Films
Authors: Zaremba Eugene , Griffin Allan
Published: April 2011

The spin susceptibility of an exchange enhanced metallic film is studied with the objective of determining how the paramagnetic properties are modified by the surfaces and the finite size of the system. In contrast to the usual treatments, an exchange interaction of finite range λ, comparable to the Fermi wavelength λF, is used. The exchange interactions are taken into account within a mean field theory approximation.The spin susceptibility is explicitly evaluated for a model in which the boundaries are treated as infinitely high potential barriers. It is found that the results depend sensitively on the value of λ. In particular, the large quantum oscillations in the surface magnetization found by earlier workers are significantly reduced in magnitude when a realistic value of the range is used. A generalized Stoner criterion determining the ferromagnetic instability in a film of thickness L is also derived from the spin susceptibility. The critical temperature TcF for a film is found to be depressed below the bulk value TcB for two physically distinct reasons. The first is referred to as a density-of-states effect and gives a depression proportional to L−1; in the absence of density-of-states effects the shift is proportional to L−2.
Some Comments on Strangeness Changing Processes and Masses of Higgs' Scalars in Gauge Theories
Authors: Gaskell R. W. , Resnick L. , Sundaresan M. K.
Published: April 2011

It is pointed out in this paper that it is not necessary to assume that the physical Higgs' scalar is very massive in order to avoid conflict with low branching ratios for certain strangeness changing decays. Results of an explicit higher order calculation in the context of a SU(2) × U(1) model in which the Glashow, Illiopoulos, Maiani mechanism is operative, are presented.
Hanle Effect in Transitions from the 5s6p and 5s7p1P1 Levels of Strontium and Coherence Narrowing
Authors: Kelly F. M. , Koh T. K. , Mathur M. S.
Published: April 2011

The lifetimes of the 5s6p and 5s7p excited singlet P levels of strontium have been measured using the Hanle effect of the 2932 and 2574 Å transitions to the 5s21S0 level. These lifetimes are compared with those reported previously using the same technique in the 7169 and 5331 Å transitions to the metastable 5s4d1D2 level. The dependence of lifetime on the density of the scattering atoms in the coherence narrowing region has also been determined.
The Lifetimes of the 72P1/2 and 72P3/2 States of Cesium
Authors: Pace Paul W. , Atkinson J. B.
Published: April 2011

The lifetimes of the 72P3/2 and 72P1/2 states of atomic cesium have been determined using delayed coincidence techniques. A nitrogen laser pumped tunable dye laser was used to excite the cesium vapor and direct measurements of the fluorescence decay yielded the following lifetimes: τ3/2(72P3/2) = 136 ± 4 ns and τ1/2(72P1/2) = 158 ± 5 ns. These values are in good agreement with recent measurements and calculations.
Proton Separation Energies for Some Rare Earth Isotopes
Authors: Burke D. G. , Balogh J. M.
Published: April 2011

Reaction Q values for the (3He,d) and (α,t) single proton transfer reactions on targets of Gd, Dy, Er, and Yb have been measured with a magnetic spectrograph. Proton separation energies, Sp, are presented for 156,157,158,159,161Tb, 161,162,163,164,165Ho, 165,167,168,169,171Tm, and 171,172,173,174,175,177Lu. Although the uncertainties of the absolute Q values are approximately 15 keV, the use of isotopically mixed and natural targets resulted in probable errors of only 1–3 keV for the differences in Q values of the isotopes identified in each target. As the proton separation energy was previously known to within 1–3 keV for one isotope of each element studied, it is now possible to present SP values with errors of a few keV for ail the nuclides listed above.
The Scattering of Positrons by Helium: Total Cross Sections up to 270 eV
Authors: Jaduszliwer B. , Nakashima A. , Paul D. A. L.
Published: April 2011

The total cross sections for the scattering of positrons by helium have been measured by the method of transmission in the 16 to 270 eV energy range. The experimental results are higher than those of Canter et al. but are in reasonable agreement with recent results of Griffith et al., and at high energies tend towards Born approximation calculations. The integral of the cross section over positron momentum is smaller than the sum rule estimate made by Bransden et al. A tentative value of (0.034 ± 0.017)πa02 is assigned to the positronium formation cross section at threshold.
Properties of a Lattice Gas Model for 3He–4He Mixtures II: Analysis of High Temperature Series for the f.c.c. Lattice
Authors: Plischke M. , Betts D. D.
Published: April 2011

For the Cheng–Schick model of 3He–4He mixtures high temperature series expansions at (a) constant density and constant concentration and (b) constant pressure and constant chemical potential difference are presented for the f.c.c. lattice for the fluctuation in the superfluid order parameter, the concentration susceptibility, and the specific heat at constant chemical potential. Analysis of the fluctuation series yields well defined lambda temperatures. In addition analysis of the concentration susceptibility series provides a less precise estimate of the tricritical concentration. The specific heat series have not proved very amenable to analysis. Upon fixing a single adjustable parameter the lambda curve of the model agrees precisely with experiment for all 3He concentrations. Estimates of tricritical exponents could not be obtained.
Electrical Transport Properties of Ga(AsxSb1−x) and (GaxIn1−x)Sb Alloys under Hydrostatic Pressure
Authors: Rosenbaum Stanley D. , Woolley John C.
Published: April 2011

Homogeneous polycrystalline n type samples of the alloys Ga(AsxSb1−x) and (GaxIn1−x)Sb have been prepared from a stoichiometric melt by directional freezing methods. Room temperature measurements of electrical conductivity and Hall coefficient as a function of hydrostatic pressure up to 12 kbars have been made on samples of different composition by means of the van der Pauw technique, all specimens used in the measurements being carefully selected to avoid the presence of grain boundary effects. The experimental curves of conductivity and Hall coefficient as a function of pressure have been fitted to a two conduction band model with various band parameters taken as adjustable. The curves thus fitted give consistent values of E12, the energy separation of the two bands, as a function of x. For (GaxIn1−x)Sb, the E12 values are in good agreement with those obtained previously from measurements as a function of temperature, no previous values having been published for Ga(AsxSb1−x). Approximate values for the coupling coefficient D12 of the alloys are also obtained.
Propagation in Irregular Multilayered Cylindrical Structures of Finite Conductivity—Full Wave Solutions
Authors: Bahar E.
Published: April 2011

Radio wave propagation problems, in irregular multilayered cylindrical structures of finite conductivity, are analyzed. The thickness and the electromagnetic parameters of the layers of the structures are assumed to be functions of the azimuth. Electric and magnetic field transforms consisting of both a discrete and a continuous spectrum of cylindrical waves provide a suitable basis for the expansion of the electromagnetic fields at any point in the unbounded structure.In the analysis, exact boundary conditions are imposed at each interface between the layers of the irregular cylindrical structure and the full wave solutions are shown to satisfy the reciprocity relationships in electromagnetic theory.When the core of the structure is perfectly conducting, the contributions from the continuous part of the wave spectrum vanish. However, in general, when the skin depth of the core is large compared to its dimensions, or when sources are located in the core of the structure and propagation in the core is of particular interest, the electromagnetic fields cannot be expressed exclusively in terms of a discrete spectrum of waves. In these cases, due to the irregularities of the structure, power is continuously coupled between the discrete and continuous constituents of the wave spectrum.
Experimental Transition Probabilities of 'Forbidden' Sulphur Lines
Authors: Kernahan J. A. , Pang P. H.-L.
Published: April 2011

We have obtained absolute transition probabilities for the 'forbidden' lines 4589 Å and 7725 Å in [SI].
The Location of Displaced Impurity Atoms in Irradiated Aluminum Crystals by Backscattering
Authors: Swanson M. L. , Maury F.
Published: April 2011

The energy spectra of 1 MeV He+ ions backscattered from single crystals of Al alloys containing 0.09 at.% Mn, 0.09 at.% Zn, 0.08 at.% Ag, or 0.03 at.% Sn have been examined in different crystallographic directions. For the annealed crystals, the minimum yield of back-scattered He+ ions from Al atoms at 40 K in a [Formula: see text] direction was [Formula: see text], and the corresponding yield from Mn, Zn, or Ag impurity atoms was (χmin)i ≤ 0.06, indicating that at least 96% of these impurity atoms had replaced Al atoms at normal lattice sites. For the Al–0.03 at.% Sn alloy, the substitutional fraction of Sn atoms was only ~50% for a slowly cooled crystal, but was increased to ~90% by a rapid (water) quench from 600 °C. Irradiation of the crystals at 40–70 K with 0.3–1.0 MeV He+ ions to doses of 1015–1016/cm2 caused the Mn, Zn, and Ag atoms to be displaced from lattice sites by the trapping of self-interstitial Al atoms. From an analysis of [Formula: see text], [Formula: see text], {100}, and {111} channeling, it was shown that the trapping configuration was the [Formula: see text] dumbbell. Both the irradiation induced dechanneling and the displacement of these impurity atoms annealed out in recovery stage III, from 180–220 K, because of vacancy interstitial annihilation. The Sn atoms were not displaced appreciably by He+ ion irradiation at 40–70 K, but a displacement occurred during stage III recovery.
States in the N = 87 Nuclei 149Sm and 151Gd Populated by the (d, t) and (3He,α) Reactions
Authors: Løvhøiden G. , Burke D. G.
Published: April 2011

The (d, t) and (3He, α) reactions on targets of 150Sm and 152Gd have been studied using a magnetic spectrograph and photographic emulsions to analyze and detect the reaction products. The (3He, α) spectra were measured at two angles for each target using 24 MeV beams of 3He. The 150Sm(d, t)149Sm reaction was studied at 13 angles with 12 MeV deuterons. The 152Gd(d, t)151Gd spectra were recorded at 4 angles with 15 MeV deuterons. The l values for a number of low spin states were determined from the (d, t) angular distributions. The ratios of (3He, α) and (d, t) cross sections were used to obtain l values for several other states. It is possible to explain the observed strength in terms of the spherical shell model although there is fragmentation of the spherical states. One striking feature is the similarity in the structures of the two nuclei. In both 149Sm and 151Gd there are high spin i13/2 states at ~0.85 MeV and h11/2 states at ~1.25 MeV.
Propagation et amortissement d'ondes acoustiques ioniques en présence de collisions ions–neutres
Authors: Cussenot J. R.
Published: April 2011

In cesium plasma where ion–neutral collisions are important, we study, theoretically and experimentally, the spatial propagation of ion waves. Good agreement between theory and experiment is obtained.
A Cell Cluster Theory for the Mean Square Atomic Displacement in an Anharmonic Crystal
Authors: Cowley E. R. , Nur H. J.
Published: April 2011

The cell cluster method is applied to the calculation of the mean square atomic displacement in an anharmonic crystal, in the high temperature or classical limit. The result is expressed in terms of a series of multidimensional integrals in real space. The lowest order and first correction terms, involving three and six dimensional integrals respectively, are evaluated to high numerical accuracy for a model including Mie–Lennard–Jones interactions between nearest neighbor atoms. The results are in fairly good agreement with experimental data for krypton.
Reevaluation of the CO2+(X2Πg) Bending Quantum
Authors: Judge D. L. , Lee L. C. , Haugh M. J.
Published: April 2011

With the assumption that the splitting of the CO2+[X2Πg(100)(3/2)] level is caused by perturbation of the CO2+[X2Πg(020)(3/2)G+] level, the bending vibrational levels are calculated and the bending frequency, ω2, is found to be 514.9 cm−1. This value is comparable to the presently observed frequency of 510 ± 10 cm−1 obtained from an analysis of CO2+(A2Πu → X2Πg) fluorescence spectra which are selectively produced by vacuum ultraviolet radiation.
Electron Correlation Effects on the Lattice Dynamics of Sodium and Potassium
Authors: Jindal V. K.
Published: April 2011

The phonon dispersion curves for sodium and potassium have been calculated using the one OPW (orthogonalized plane wave) bare electron matrix elements and the dielectric function of Vashishta and Singwi. Results are compared with experimental results as well as with similar calculations using the dielectric function of Geldart and Taylor. It is found that the screening function of Vashishta and Singwi gives at least as good an agreement with experimental values as obtained from the screening function of Geldart and Taylor. The interionic potentials for these metals have also been calculated and compared with similar calculations done previously. The reason for the appreciable difference between the potentials is discussed.
Détermination expérimentale de la densité électronique d'une colonne de plasma utilisant les propriétés de la propagation d'une onde plasma
Authors: Glaude Vital M. , Boucher Claude , Koechlin François
Published: April 2011

In this work we use the properties of the electron plasma wave propagation in its fundamental mode in order to determine the electron density of a warm plasma column (Te ~ 16 eV) of a 1 cm radius, confined by a 800 G magnetic field, and surrounded by a 10 cm inside diameter stainless steel cylinder. The measurements yield the value of the axial density of the column (Ne ~ 109 cm−3) and its precision depends on the determination of Te and [Formula: see text]. The results are compared with those obtained by the measurement technique of the ordinary TM010 microwave cavity resonator. The two methods are in fairly good agreement.
Phenomenological Description of High Spin States in Doubly Even Rare Earths
Authors: Heras C. A. , Abecasis S. M.
Published: April 2011

Without recourse to a specific model, assuming only that the global structure of spectra is rotational, a good fit of energy levels in doubly even rare earth nuclei is achieved, including the so-called backbending at high spins.
Cylindrical Distribution of Matter in Longitudinal Electric and Magnetic Fields
Authors: Krori K. D. , Chakrabarty Jayantimala
Published: April 2011

We have presented here some results on test particles in the field of a cylindrical distribution of matter in a longitudinal electric or magnetic field.
Dielectric Functions in Wavelength and Thermally Modulated Spectroscopy
Authors: Mondio G. , Saitta G. , Vermiglio G.
Published: April 2011

More refined dielectric functions at three dimensional critical points, both for wavelength and thermomodulation spectroscopy, are given and compared to approximate ones.
Symétrisation de la longueur et du temps dans un espace de Lorentz C3 en algèbre lineaire, pouvant servir en théorie trichromatique des couleurs
Authors: Demers Pierre
Published: April 2011

It is proposed to express time as a composition of three auxiliary variables tx, ty, tz. which will be named components of vector t. Event P is expressed as a composition of six variables x, y, z, tx, ty, tz in R6 or of three coordinates ξ = x + itx, η = y + ity, and ζ = z + itz in C3. A quadratic function is defined, called 'carré simple', of P, which comes to the same as taking the square of the Lorentzian form of P in R4, equalling.s2. In this formalism, length r(x, y, z) and time t (tx, ty, tz) play roles exactly symmetrical and are exchangeable one for the other. This formalism will be applied to trichromatic theory.
Resonance Lines in the Fourth Spectrum of Silver: Ag IV
Authors: Joshi Y. N. , Kushawaha V. S. , Benschop H. , VanKleef Th. A. M.
Published: April 2011

The spectrum of silver was photographed recently on a 10.7 m grazing incidence vacuum spectrograph at NBS Laboratory in Washington, D.C. On the basis of our measurements, we have established the ground state 4d8a3F and three excited odd states, 4d75pz3(D°F°G°), in Ag IV. Eighteen lines have been classified in this spectrum.
Charge Transport in Dilute Aluminum Alloys
Authors: Kus F. W. , Carbotte J. P.
Published: April 2011

We have calculated the electrical resistivity of several dilute aluminum based alloys for which experimental data exist on the deviation from Matthiessen's rule(DMR). We take account of the anisotropy in the ideal (pure metal) scattering and its modification on adding impurities. This is a major source of DMR. In addition, we compute the effect of inelastic impurity scattering, interference between impurity and ideal scattering, Debye–Waller factors, and also the effect of mass changes on the alloy resistivity. While some of these mechanisms for DMR can be of importance under specific conditions, they should be included only after the major effect of anisotropy in the ideal scattering has been properly treated.
Photoelectric Effect Investigations with Linearly Polarized 847, 1368, and 1779 keV Photons
Authors: Logan B. A. , Jones R. T. , Ljubičić A. , Dixon W. R. , Storey R. S.
Published: April 2011

The spatial distribution of photoelectrons, ejected from the K shell of atoms with high atomic numbers by linearly polarized 847, 1368, and 1779 keV photons, has been investigated. The experimental results are in good agreement with existing theoretical predictions when the predictions are modified to allow for distortions produced by scattering of the photoelectrons in the photoelectric target.
Gamma Decay of the Lowest T = 2 State in 36Cl
Authors: Martin D. J. , Szücs J. A. , Kelly D. T.
Published: April 2011

The first T = 2 state in 36Cl has been populated by the 34S(3He,pγ)36Cl reaction at a beam energy of 13 MeV. The state is observed to γ decay to levels at 1604 keV (62%) and 1163 keV (38%).
Quelques applications de la réflexion frustrée en optique instrumentale
Authors: Cielo P. , Delisle C.
Published: April 2011

It is shown how the transmission of an optical system based on frustrated internal reflection may be modified if one makes use of the dispersion in the input prism. Two examples are considered, a low pass filter and a wide band beam splitter. It is also shown that by using birefringent substances one can correct the inequality which is usually observed between the transmission of the parallel and perpendicular components of a nonpolarized light beam which traverses an optical system based on frustrated internal reflection.[Journal translation]
On the Mechanism of Inelastic Proton–Nucleus Interactions at 24 GeV/c
Authors: Zafar M. , Irfan M. , Ahmad I. , Ahmad Z. , Shafi M.
Published: April 2011

The mechanism of inelastic proton–nucleus interactions at ~ 25 GeV energy of incident particles has been investigated. The predictions of the tube and cascade models about the dependence of mean shower multiplicity on the mass number of the target nucleus and the energy of incident particles have been compared with the experimental results. Several other results such as the effective number of nucleons in nucleon–nucleus collisions, the values of [Formula: see text], [Formula: see text], [Formula: see text], etc. have been experimentally obtained and compared with the predictions of the models. It has been concluded that the cascade mechanism of interactions, which takes into account the 'trailing effect', satisfactorily explains many of the observed results.
Photoproduction of Gravitons in Static Electromagnetic Fields
Authors: Papini G. , Valluri S. -R.
Published: April 2011

The cross sections for the process of photoproduction of gravitons in Coulomb and magnetic dipole external fields have been calculated. The calculation, which is linear in the gravitational coupling constant κ, is completely covariant, manifestly gauge invariant, and divergence free. The results to this order in κ are exact. Expressions for the case of extended sources have also been obtained and found to be in agreement with the results of other authors.
Photoproduction of Gravitational Radiation by Pulsars
Authors: Papini G. , Valluri S. -R.
Published: April 2011

Emission of gravitational radiation via photoproduction in static electromagnetic fields can equal or exceed the quadrupole contribution for pulsars whose ellipticity ε < 10−3 and may play a role in the cooling of the star. Contrary to the quadrupole emission case, radiation can take place also when the direction of the dipole moment and the rotation axis coincide. Radiation rates are also estimated for several frequency ranges of the photon spectrum.
A Soft Scalar Theorem
Authors: Gaskell R. W.
Published: April 2011

We examine a soft scalar theorem which has proved useful in the evaluation of certain Feynman graphs. The use of this theorem is described in connection with the determination of the [Formula: see text] coupling in a unified model of weak and electromagnetic interactions.
Plasma Fluctuations Induced by Subthreshold Pump Fields
Authors: Leboeuf J. N. , Johnston T. W.
Published: April 2011

We present in this work three equivalent methods to calculate stable plasma density fluctuations induced by a uniform oscillating electric field near the plasma frequency, somewhat below threshold for generation of parametric electrostatic instabilities. The first method is essentially that of Silin and Sanmartin which is based on the electron and ion Vlasov equations, each transformed to their respective oscillating frames of reference, but here we include effects associated with atomicity of the charges to obtain plasma density fluctuations below threshold. The second approach, which is a more straightforward development of the pumped plasma fluctuations, uses the 'dressed test particle' concept and the nonlinear Poisson equation in the frame of reference oscillating with the electrons. These equations are given for any number of waves and the two results agree exactly. The third and most demanding derivation undertaken here is a modified DuBois–Goldman theory, limited to three waves plus pump, developed by one of us from the rest frame nonlinear Poisson equation for parametric stability analysis. Contrary to an assertion by Hagfors and Gieraltowski, the modified DuBois–Goldman method gives the same results as the other two to second order in field strength.
Fine Structure Intervals in Transition Elements
Authors: Karwowski Jacek , Saxena K. M. S. , Fraga Serafin
Published: April 2011

A new formulation for the evaluation of the matrix elements of the spin-own orbit interaction in many-electron atoms has been applied to the evaluation of the interaction matrices for pN, dN, and fN configurations, using functions that are simultaneous eigenfunctions of the operators J2, L2,S2, and.Jz; the complete results are available as indicated in the text. Using this formulation, the fine structure intervals for the ground states of the neutral atoms and the first three positive ions of the elements of the three transition series have been calculated within the framework of the monoconfigurational approximation, including the electrostatic and spin-own orbit interaction between the states arising from the configuration under consideration. In each case, the spin–orbit parameter and the set of Slater–Condon integrals, obtained from the numerical Hartree–Fock function for the ground state, were used.
Kinetic Theory–Memory Equation Approach to Nuclear Magnetic Relaxation in Molecular Gases. II. Application to Hydrogen
Authors: McCourt F. R. , Raidy T. E. , Rudensky T. , Levi A. C.
Published: April 2011

The kinetic theory–memory equation kernel obtained in the preceding paper is evaluated for molecular hydrogen at 296 K in a 'single relaxation time' approximation and the low density T1 vs. ρ curve in the region of the T1 minimum (as predicted by a fit of the theoretical expression for the high density linear slope T1/ρ) is compared with the most recent and accurate experimental results. Excellent agreement is found over the entire nonlinear region. The cross sections extracted for the spin-rotation and dipolar contributions to the relaxation time T1 are found to have the values σsr = 0.493 Å2 and σd = 0.457 Å2, consisting in the main of pure reorientation contributions (~90% in each case).
Theory of Self-Broadening in an Adiabatic Representation
Authors: Royer Antoine
Published: April 2011

A theory of self-broadening of spectral lines is formulated within the frame of an adiabatic representation; this allows one to treat all the electrons in the gas as indistinguishable and, thus, to include the possibility of electron exchange between atoms, which is responsible for much of the interatomic interaction. We also include the nuclear statistics, which can have a nonnegligible effect in self-broadening.
Real and Virtual Kohn Effect in Palladium by Inelastic Neutron Scattering
Authors: Miiller A. P.
Published: April 2011

A detailed study has been made of the anomalous lattice vibrations in palladium by inelastic neutron scattering. Anomalous shifts in the phonon frequencies are particularly evident along the [0ζζ] T1 branch at reduced wave vectors [Formula: see text] to 0.4, becoming rapidly weaker at 'off symmetry' wave vectors. (Rather similar effects have also been observed in platinum.) The phonon wave vectors corresponding to possible Kohn transitions in the symmetry planes have been computed, using the Fermi surfaces given in the literature. The results indicate that the anomalous frequency shifts arise largely from transitions across the 'heavy' hole Fermi sheet formed from the fifth band electrons. Measurements along the T1 branch at temperatures between 8 and 853 °K show that the anomalous frequency shifts are smeared out in wave vector and perhaps weakened with increasing temperature. The corresponding phonon line widths, obtained by correction of the neutron groups for instrumental resolution, were found to be anomalously broadened as well, particularly at 8 °K where anharmonic effects are expected to be small. This suggests that the anomalous line widths reflect, in large part, the reduction in phonon lifetimes (and in electron lifetimes) arising from real Kohn transitions. This is believed to be the first identification of phonon line broadening because of electron–phonon interaction in a nonsuperconductor.
A Detailed Study of the g9/2 Analogue Resonance in 59Cu by the 58Ni(p,γ) 59Cu Reaction
Authors: Cooke B. E. , Leslie J. R. , Robertson B. C. , McLatchie W.
Published: April 2011

The resonance in the reaction 58Ni(p,γ)59Cu at Ep = 3.546 MeV has been studied. Gammaray angular distribution studies have clarified the assignment of the resonance (Ex = 6903 keV) and the level at Ex = 3042 keV as Jπ = 9/2+. The resonance strength determination, (2J + 1) × ΓpΓγ/Γ = 6.2 ± 0.7 eV, implies an M1 analogue to antianalogue transition rate of 0.4 W.u. The data are compared with existing experimental results and with theoretical predictions.
Polarization Gaussian p Functions for the Beryllium Atom: Ab initio Calculations on BeH2 and BeH+
Authors: Mezey P. G. , Csizmadia I. G. , Strausz O. P.
Published: April 2011

A set of Gaussian p orbital exponents was obtained by optimizing a (9s5p) Gaussian basis set for an excited state of the beryllium atom and the ground state of the beryllium negative ion. In the optimization procedure the method of conjugate gradients was applied for the energy functional. The optimum (9s5p) basis set was tested on the BeH2 and BeH+ structures.
Investigation of the Thermal Properties of Solid CH3D at Very Low Temperatures
Authors: Jones E. P. , Morrison J. A. , Richards E. L.
Published: April 2011

Heat capacity measurements have been performed on solid CH3D over the range 0.15 < T < 4 K where a large Schottky anomaly occurs. The entropy change in the anomaly is estimated to be 1.80 ± 0.10R which is about 14% less than that corresponding to complete orientational ordering of the molecules and total conversion of nuclear spin symmetry species. Some time effects associated with thermal equilibration have also been studied.
Plane MHD Steady Flows with Constantly Inclined Magnetic and Velocity Fields
Authors: Chandna O. P. , Toews H. , Nath V. I.
Published: April 2011

Plane steady state viscous fluid flows, in which the magnetic field and velocity field are constantly inclined to one another, are considered. Necessary and sufficient physical conditions have been derived for flows with zero current density and the general solutions for these flows are obtained. Irrotational flows and flows with straight streamlines are also studied.
Collisional Transfer of Rotational Energy in Mixtures of Methanol with Ne, Ar, and D2
Authors: Haque S. S. , Lees R. M.
Published: April 2011

Steady state microwave double resonance experiments are reported for dilute mixtures of CH3OH in excess Ne, Ar, and D2. The results for Ne and Ar are, in general, similar to previous results for He, and those for D2 to H2, with both classes of collision partners displaying a decrease in collisional transfer signal with increasing mass of the partner. A simple qualitative analysis indicates that the ratios between the rates of different types of collision-induced transitions are quite similar for the members of a class. For He, Ne, and Ar, the rate constant for Δk = 0 transitions is of the order of 8 times that for a Δk = ±1 transition, while for H2 and D2 the ratio is about 4.
Electromagnetic Instability in Interpenetrating Electron–Ion Plasmas with Generalized Distribution Functions
Authors: Lai C. S. , Suen Robert
Published: April 2011

The electromagnetic instability associated with plasma waves propagating transverse to a uniform magnetic field, B0, is studied for interpenetrating plasmas with generalized distribution functions, based on the linearized Vlasov–Maxwell equations. The plasma waves can no longer be separated into the ordinary and extraordinary modes, owing to the different densities, temperatures, and drift velocities of two plasma streams. It is found, as in the case of two bi-Maxwellian counterstreaming plasmas, that the instability can occur in rather low-β plasmas.
Influence de la relaxation rotationnelle dans le déclenchement passif d'un laser CO2. Application aux molécules C3H4 et CH3Cl
Authors: Meyer-Bourbonneux Françoise , Dupré Jacques , Meyer Claude
Published: April 2011

Passive Q switching in a CO2, laser was observed using allene and methyl chloride gases.Investigation of the high resolution spectra of these two gases gave the assignment of the pulsing lines. A theoretical scheme was used to interpret this phenomenon. Calculations show the important role of rotational relaxation in the absorbers.
Generalized characteristic functions for simultaneous linear differential equations with variable coefficients applied to propagation in inhomogeneous anisotropic media
Authors: Bahar E.
Published: April 2011

A wide class of physical problems can be reduced to sets of simultaneous linear differential equations with variable coefficients. For critical coupling regions of the independent variable where the characteristic values of the coefficient matrix tend to merge, the standard technique employing similarity transformations does not convert the original set of differential equations into a form that is suitable for numerical computations. For these critical coupling regions we employ a nonsingular transformation matrix associated with variable characteristic values to convert the original equation to a form that can be more readily resolved analytically (using an iterative approach) or numerically. The method developed is applied to problems of radio wave propagation in inhomogeneous, anisotropic, dissipative media with critical coupling regions.
Dynamics of cavitation bubbles
Authors: Wentzell R. A.
Published: April 2011

The dynamics of an adiabatic gas–filled bubble in a viscous liquid is studied when subjected to a tension wave produced by a shock wave reflected off the water surface. Below a critical bubble size the water does not cavitate. Numerical solutions show that cavitation causes severe prolongation and attenuation of the original tension wave.
The interaction dipole
Authors: Weiss Shmuel
Published: April 2011

Present knowledge concerning the dipole which forms between a pair of molecules due to electron cloud overlap and electron correlation is reviewed. The experimental information, derived from collision-induced spectra in the infrared, is analyzed. Theoretical calculations of the dipoles are described. Increasing sophistication in both approaches is shown to lead eventually to agreement between them. The case of the rare gases—the most researched by far—is taken up in detail, and the dipoles there are shown to have a common reduced form. They are also shown to correlate with other properties, in particular the intermolecular potential. Ternary interaction dipoles are touched upon.
X-ray study of the α–β transformation of berlinite (AlPO4)
Authors: Ng H. N. , Calvo C.
Published: April 2011

The α–β transformation of berlinite (AlPO4) at 586 °C was studied by X-ray diffraction. Atomic displacements were obtained from results of least-squares refinement of data taken between room temperature and 600 °C using reflections whose intensity is unaffected by Dauphiné twinning. The results suggest a rotational motion of the PO4 and AlO4 tetrahedra around the two-fold axis together with a translational motion along the same axis as the transition is approached from below. The vibrational amplitudes of the atoms increase with temperature and have exceeded half of the separation between Dauphiné twin-related configurations at 500 °C. The final β-phase configuration is not achieved by this twinning due to the mismatch of the two configurational potential minima in the a direction. Analysis of the intensity vs. temperature data favours a single minimum model for the β phase configuration over an order–disorder model. The β-AlPO4 structure consists of alternate PO4 and AlO4 tetrahedra sharing all four corners with P—O and Al—O distances 1.505 and 1.694 Å respectively. The results are correlated with those obtained from temperature dependent studies by Raman scattering and by EPR on Fe3+-doped AlPO4.
Polarization transfer and relaxation induced in collisions of excited alkali atoms
Authors: Dashevskaya E. I. , Nikitin E. E.
Published: April 2011

We present an approximate theory of intramultiplet mixing, relaxation, and polarization transfer in excited alkali atoms, valid for all magnitudes of the fine-structure splitting. The theory is developed as the generalization of the previously postulated theory of fine-structure mixing induced in adiabatic and quasiresonant collisions. In the adiabatic region, the theory predicts a change in the sign of the coefficient for polarization transfer between the components j = 1/2 and,j = 3/2 of the 2P resonance doublet, as the Massey parameter for this transition changes.
Thermoluminescence of irradiated ammonium perchlorate crystals
Authors: Radhakrishna S. , Riggin M. , Whippey P. W. , Jacobs P. W. M.
Published: April 2011

The thermoluminescence of single crystals of ammonium perchlorate irradiated with X rays, uv light, or high energy electrons has been measured between 80 and 420 K. With a heating rate of 5 K/min. prominent peaks occur at 95, 113, 134, 246, and 320 K; an additional peak is found at 347 K after longer irradiation times. The absorption spectrum of uv-irradiated ammonium perchlorate has also been measured and shows bands at 300, 360, and 610 nm. A comparison of these data with chemical and spectroscopic evidence obtained by other workers has permitted the probable identification of ClO3−, ClO−, ClO2, and F centres as radiation products. Three thermoluminescent peaks remain unassigned.
Vector–vector–pseudoscalar couplings, radiative decays, and possible existence of ψ-like pseudoscalar mesons
Authors: Cordes J. G. , Kiang D. , Tsai S. Y.
Published: April 2011

Possible interactions of the ψ particles are analyzed with emphasis on vector–vector–pseudoscalar couplings. Radiative decays are studied in some detail in the context of the vector dominance model. The possibility that there might exist ψ-like pseudoscalar mesons which couple strongly to the ψ's is examined. The relevance of our phenomenological analysis to the charm and color scheme interpretations of the new particle is discussed.
The fifth spectrum of indium: In V
Authors: Joshi Y. N. , VanKleef Th. A. M. , Kushawaha V. S.
Published: April 2011

The indium spectrum has been photographed in the region 575–190 Å on a 10.7 m grazing incidence vacuum spectrograph. On the basis of the improved data and parametric calculations of 4d9 and 4d85p configurations and the intensity calculations of the allowed transitions, the spectrum has been revised. Many new levels have been found and the designations of several levels established earlier have been changed. Fifty-five lines have been classified in this spectrum.
Calculation of intrinsic carrier concentration in tellurium taking anisotropy into account
Authors: Champness C. H.
Published: April 2011

The intrinsic carrier concentration in tellurium is calculated at room temperature from measured values of electrical conductivity, Hall coefficient, and transverse magnetoresistance, taking anisotropy into account in a simple way. The model assumes one value of mobility parallel and another perpendicular to the c axis for both the electrons and holes.
Pion–pion scattering in a model satisfying crossing symmetry, analyticity, and approximate unitarity
Authors: Boal D. H. , Moffat J. W.
Published: April 2011

Phase shifts for π–π scattering are obtained from a model satisfying Mandelstam analyticity, exact crossing symmetry, and approximate unitarity in the range 2mπ ≤ s1/2 ≤ 1.3 GeV. The low energy region is dominated by the ρ, ε, and S* poles; the δ00 phase shift is in good agreement with the data obtained by Protopopescu et al. A detailed comparison is made with the available world's data on π–π scattering.
Laser-excited fluorescence of 15NO2 and N18O2
Authors: Brand J. C. D. , Hardwick J. L. , Teo K. E.
Published: April 2011

Measurements are reported of the resonance fluorescence of 15N16O2 and 14N18O2 excited by the 488,496, and 514 nm radiation of an Ar+ laser. The frequency displacements in these spectra are consistent with values calculated previously, using potential constants for the electronic ground state of NO2 derived from the rotational and vibrational constants of NO2 and 15N16O2 but containing no information from N18O2 spectra; the agreement obtained for the latter isotope is therefore a partial test of the potential field.In these spectra, fluorescence occurs from vibronic B2 levels of the Ã2B2 state possessing 7500–8500 cm−1 of vibrational energy. A number of examples are described in which the emission from these vibrationally excited levels shows an anomalous intensity distribution or K-selection rule (e.g., ΔK = ±2) as a result of Coriolis and/or spin–orbit coupling between vibrational levels of the upper electronic state.
Criticism of 'nonlinear effects in ferromagnetic metals'
Authors: Kurn Andrew , Cochran J. F. , Heinrich B.
Published: April 2011

The theory of Lieu and Alexandrakis is shown to be unable to explain the appearance of nonlinear effects in the transmission of microwave radiation through ferromagnetic metal foils when the incident rf magnetic field is polarized parallel to the static magnetic field. It is also estimated that rf field amplitudes of approximately 85 Oe would be required to observe nonlinear effects in nickel for an applied frequency of 9 GHz.
On the connection between acausal propagation and the non-local structure of higher spin fields
Authors: Capri Anton Z. , Shamaly Ahmed
Published: April 2011

We show that a free spin 3/2 theory of the Pauli–Fierz type displays nonlocal structure. Similarly, a spin 1 theory coupled via an electric quadrupole to an external field also shows nonlocal structure. This is in sharp contrast to the cases of spin 0, 1/2, and 1 which do not have any nonlocality even in the presence of minimal coupling to an electromagnetic field. This leads us to conjecture that the acausal propagation discovered for spin 3/2 and spin 1 is due to additional structure of these fields.
The distortion moment spectrum of 28SiH4: The microwave Q branch
Authors: Ozier I. , Lees R. M. , Gerry M. C. L.
Published: April 2011

Eleven pure rotational Q-branch transitions have been observed between 8 and 25 GHz in the distortion moment spectrum of 28SiH4. The spectrometer used was a conventional Stark-modulated instrument modified to have a sensitivity of ~1 × 10−11 cm−1. From the eleven frequencies, values have been determined for the single quartic tensor distortion constant DT, the two sextic constants H4T and H6T, and the three octic constants L4T, H6T, and L8T. These are (in Hz): DT = (74 751.4 ± 1.6); H4T = −(6.044 ± 0.010); H6T = (2.598 ± 0.003); L4T = (46.5 ± 1.5) × 10−5; L6T = −(37.9 ± 0.8) × 10−5; L8T = −(76.6 ± 2.1) × 10−5. The errors here are the standard deviations obtained from a least squares analysis; estimates are also given of the absolute errors. For possible application in other high resolution studies of silane, the constants have been used to calculate all Q-branch splittings for J ≤ 20. The present results are compared to those obtained by double resonance methods by Kreiner and Oka; a definite identification has been found for one of their lines which had previously been tentatively assigned to another transition. The combination-differences data of Pierre, Guelachvili, and Amiot have been reanalysed on the basis of the current results to obtain improved values of the rotational constant and the quartic and sextic scalar distortion constants.
The rf power and electron energy distribution measurements in a beam–plasma interaction experiment: Nonlinear saturation and reflection effects
Authors: Sugawara M. , Bergevin B. , Stansfield B. L. , Gregory B. C.
Published: April 2011

After a review of nonlinear saturation experiments and theory in beam–plasma interactions, the experiment is described and measurements of the dispersion relationship, the spatial growth of the wave power, and the electron energy distribution are presented. The wave power measurements are compared with a simple theory taking into account reflections from the end of the machine. Although good agreement is obtained for the growth rate and wave number, the damping coefficient of the reflected wave is greater than linear theory predicts. Some possible linear and nonlinear explanations are suggested.
The Coster–Kronig L shell yield f23 of Ho and Tm
Authors: Douglas D. G.
Published: April 2011

The L shell Coster–Kronig yield f23 has been measured for Z = 67 and Z = 69 by a method employing fluorescence X-ray excitation with a 241Am source, the use of Sm and Gd critical absorption filters, and Kα–Lα coincidences. The results (0.143 ± 0.010 and 0.148 ± 0.007 respectively) are in good agreement with the calculations of Chen and Crasemann which made use of an independent particle model and a Green–Sellin–Zachor potential.