bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of the Superconducting Proximity Effects by Josephson Tunneling
Authors: Greenspoon S. , Smith H. J. T.
Published: April 2011

We have studied Josephson tunneling in lead – lead oxide – copper – lead junctions with the intent of investigating the proximity effects between normal (Cu) and superconducting (Pb) metals. Zero-voltage tunneling currents of the order of milliamps have been observed in junctions with varying copper thicknesses and electron mean free paths. We have interpreted our measurements of the temperature dependence of the maximum Josephson current in terms of a model based on the de Gennes – Werthamer theory of the proximity effects. As a result of our work we conclude that the de Gennes – Werthamer theory has considerable usefulness outside the strict limits of validity in which it was derived.
Meteor Spectroscopy Using an Image Orthicon
Authors: Hemenway C. L. , Swider A. , Bowman C.
Published: April 2011

A brief description of a technique for recording faint meteor spectra with a high sensitivity image orthicon tube is given. The use of a video tape recorder technique makes it possible to study the development and decay of time dependent features such as the auroral green line 5577 Å in meteor spectra.
Comments on NN → NNπ in the Isobar Model
Authors: Beder Douglas S.
Published: April 2011

We examine an isobar model for various charge modes of the reaction NN → NNπ, with careful attention to interference between isobar amplitudes. We find interference to be important (contrary to earlier assumptions in the literature) for 600 MeV protons, and present the corrected predictions of the isobar model for ratios of π+, −, 0 total production cross sections.
On π Production in Nuclei
Authors: Beder Douglas S.
Published: April 2011

The usual expression used for π production in nuclei takes the form one expects of a classical process occurring in an inhomogeneous gas with a specified momentum distribution. In fact, this is shown to be formally inconsistent with quantum mechanics. We therefore establish a consistent quantum mechanical treatment of this problem and examine the cross section predictions of this formalism in appropriate limits. At best, a clumsy justification of the classical picture can be achieved.
Inelastic Neutron Scattering With Fission Neutrons
Authors: Nichol L. , Kennett T. J.
Published: April 2011

A detailed investigation has been conducted of the usefulness of fission-spectrum neutrons for inelastic neutron scattering studies. A Ge(Li)–NaI(Tl) annular pair spectrometer was employed in conjunction with a versatile in-core irradiation facility to conduct this evaluation. The Doppler broadening and shift which were observed are quantitatively described through the use of a simple model developed for the system. The effectiveness of neutron filters for the reduction of capture reactions which normally produce unwanted background is also discussed. Results indicate that gamma-ray deexcitation, following neutron inelastic scattering, can be readily identified and quantitatively evaluated. During the course of this study resonant neutron capture in the 35 keV resonance of 28Al was observed thus indicating the feasibility of investigation of this type of reaction. Lifetime results for levels in 19F were obtained using a Doppler attenuation method and a possible discrepancy in (dE/dx) values was indicated.
Transverse Noise of Hot Electrons in n-Type Germanium
Authors: Hart L. G.
Published: April 2011

This work is an extension of previous analysis of high-field, hot-electron noise in n-type germanium. The previous analysis, developed to explain the author's observations of field-direction (longitudinal) noise, is extended here in an attempt to explain the hot-electron, transverse noise observations of Erlbach and Gunn.In the model adopted, the transverse current fluctuations, resulting from intravalley and intervalley scattering, within the interelectrode volume (electrode area × separation), yield both thermal and intervalley contributions to the noise temperature. For two of the three crystal orientations considered, the intervalley noise is negligible, but in the third case, the two contributions are of the same order.Individual valley currents, populations, and relative intervalley transition rates are calculated from Nathan's analysis, and the Barrie–Burgess theory of high-field transport provides the valley electron temperatures. The intervalley scattering data of Weinreich, Sanders, and White yield absolute values of the intervalley scattering probabilities.Poor agreement is found with the Erlbach–Gunn observations of transverse noise temperature, which may be due to the shunting effect of the portion of the sample exterior to the interelectrode volume.
Etude de Cavités Electromagnétiques Perturbées par un Diélectrique : Application aux Masers
Authors: Tessier M. , Vanier J.
Published: April 2011

In certain types of masers it is common to use storage quartz bulbs in microwave cavities. We describe the effects of such bulbs on the field components, the frequency, the quality factor, and the filling factor. Two different methods are used to solve the problem: one of these methods is classical and exact and is based on the continuity of the field components and on the equations of separation; the other method used is the so called "method of moments". The two methods give essentially the same results. Experiments have been performed to verify the theoretical results. We have observed that the quartz storage bulb produces a slight negative frequency shift, a notable lowering of the quality factor and a very slight change in the filling factor; the perturbed mode appears as a superposition of other modes. It is concluded that to reduce the perturbation we must use extremely thin bulbs with walls very close to the cavity walls.
Some Effects of Pressure on Superconductivity
Authors: Carbotte J. P. , Vashishta P.
Published: April 2011

We have calculated the effect of hydrostatic pressure on select properties of a number of simple superconducting metals. We discuss the changes with decreasing volume in the critical temperature, the zero temperature gap, the condensation energy, and the normal state specific heat. Semiquantitative agreement with experiment is obtained in all cases. Throughout, the Eliashberg formulation is employed. Information on the kernels entering into these equations is taken from quasi particle tunneling data at zero pressure. At finite pressure the kernels are rescaled according to a simple model.
Electron Paramagnetic Resonance of the V3+ Ion in CsAl(SO4)2∙12H2O
Authors: Clarke J. G. , MacKinnon J. A.
Published: April 2011

The electron paramagnetic resonance spectrum of the V3+ ion in CsAl(SO4)2∙12H2O single crystals has been studied in the {100} and {111} planes at 4.2 °K with an X-band microwave spectrometer.
Calculation of the Nuclear Properties of 53Cr by the Unified Model
Authors: Csürös M. , Cameron J. A. , Zámori Z.
Published: April 2011

The results of a calculation based upon the intermediate coupling approach of the unified model are presented for the low energy nuclear properties of the 53Cr isotope.
Measurement of the Radiative Width of the 6+, 8.79 MeV Level of 20Ne
Authors: Diamond W. T. , Alexander T. K. , Häusser O.
Published: April 2011

Using the 4He(16O, γ)20Ne reaction, ωγ = 1.42 ± 0.17 eV was obtained for the 6+, 8.79 MeV level of 20Ne. The experimental E2 transition probabilities in the ground state band of 20Ne favor a microscopic model over a simple rotational description.
Fluid Mixtures of 6:12 Molecules in the Percus–Yevick Theory Using the Energy Equation
Authors: Grundke E. W. , Henderson D. , Murphy R. D.
Published: April 2011

The thermodynamic properties of a fluid mixture are calculated using the 6:12 potential together with the energy equation and the Percus–Yevick theory. The agreement with the results of simulation studies is good.
Gain Measurements at 10.6 μm in Pure CO2 Discharges
Authors: McQuillan A. K. , Yeh G. , Carswell A. I.
Published: April 2011

A two beam null method has been used to measure gain at 10.6 μ in a pure CO2 discharge for several gas pressures, flow velocities, and discharge currents. It is shown that the presence of CO, produced by dissociation of CO2, leads to the dominant population inversion mechanisms. Carbon monoxide is found to enhance the gain both by increasing the population of the upper level and by aiding in the depletion of the lower level population.Highest gain values were found for gas pressures of about 1 Torr and current values of the order of 10 mA. The maximum gain obtained was 40% per meter in a sealed system.
Heating of a Theta-Pinch Plasma by a CO2 Laser
Authors: Martineau J. , Pépin H.
Published: April 2011

The heating of a theta-pinch deuterium plasma by a CO2 laser has been studied as a function of pulse duration and energy. A hydrodynamical approach was used with temperatures and densities assumed uniform in a fully ionized plasma. This model takes into account the dynamics of the magnetic field, the axial and radial magnetic confinement, the shape of the laser pulse, and energy transferred to the plasma by inverse bremsstrahlung. We discuss the results (dimensions, temperature, absorbed power) snowing that an increase in pulse duration results in higher electron and ion temperature.
Superconducting Magnet of Intermediate Resistivity Substrate and Filamentary Superconductor Composite
Authors: Atherton David L.
Published: April 2011

This note reports a 3 kg superconducting magnet using a composite conductor of twisted fine filamentary niobium titanium in a copper alloy matrix with resistivity of 0.44 × 10−6 Ω cm at 10 °K, about 50 times that of high conductivity copper. The coil operates repeatedly at short sample critical current without potting.
The Dynamics of Ammonium Ions in (NH4)2SO4
Authors: Trefler Martin
Published: April 2011

The reflectivity of paraelectric and ferroelectric (NH4)2SO4 and (ND4)2SO4 has been measured in the far infrared and a torsional oscillation mode has been observed in the ferroelectric phase. Evidence is presented indicating that a reorientation of the ammonium ions occurs at the ferroelectric phase transition.
Interaction of CO2 Laser Radiation with Solids. I. Drilling of Thin Metallic Sheets
Authors: Gonsalves J. N. , Duley W. W.
Published: April 2011

A quantitative analysis of the minimum CW CO2 laser power required for the drilling of thin stainless steel sheets in vacuum and in air is reported. These results are interpreted theoretically in terms of a simple cylindrical source model. A nomograph is given for the prediction of critical powers for CO2 laser drilling of other metals.
Application of the Functional Formalism to Investigation of the Photoelectric Counting Distribution
Authors: Zardecki Andrzej
Published: April 2011

A general formula is derived relating the generating function of the N-fold photoelectron counting distribution to the characteristic functional of the optical field. For a stationary Gaussian radiation field the generating function is expressed as an infinite product involving eigenvalues of a set of integral equations. The results of Bédard, Dialetis, and Cantrell are shown to hold as special cases. Addition of photoelectric counts from correlated Gaussian light is analyzed and the appropriate generating function is given.
On the Stability of Precipitate–Matrix Interfaces in Dilute Ternary Systems
Authors: Coates D. E.
Published: April 2011

Using linear perturbation methods, a precipitate–matrix interface stability criterion is obtained for dilute ternary systems. The calculation takes account of capillarity, transport in the precipitate, and ternary diffusional interaction. The general stability criterion contains a term reflecting the destabilizing influence of the solute gradients (i.e., the point effect of diffusion) and a term representing the stabilizing influence of capillarity. Two limiting cases are treated in detail—insignificant transport in the precipitate and negligible ternary diffusional interaction. It is demonstrated that in these two cases the two solutes behave in a cumulative fashion.
Intermediate Coupling in 55Fe
Authors: Csürös M. , Cameron J. A. , Zàmori Z.
Published: April 2011

Calculations based on the collective model with intermediate coupling between the surface oscillations of the even–even core 54Fe and 29th neutron have been carried out. Level energies, spectroscopic factors, and electromagnetic properties are obtained in good agreement with experiment.
Optical Pumping and Optical Detection of Spin-Polarized Electrons in a Conduction Band
Authors: Parsons R. R.
Published: April 2011

Spin-polarized electrons are created in the conduction band of p-type GaSb by excitation with σ+ or σ− circularly polarized light. The degree of polarization of the photoluminescence is used to measure the optically pumped spin polarization. The measurements as a function of transverse magnetic field yield the spin-relaxation time and the lifetime of the photocreated electrons. The degree of polarization oscillates as a function of the photon energy of the excitation light. This effect is associated with mechanisms of rapid energy loss involving optical and acoustical phonons. The optical pumping is studied as a function of temperature in the range 3.5 °K ≤ T ≤ 11 °K. A maximum spin polarization [Formula: see text] is obtained at [Formula: see text]. The efficiency of the optical pumping is significantly increased with the application of a weak longitudinal magnetic field.
On Anisotropy of Growth of Polycrystalline Ice in Constitutionally Supercooled Water
Authors: Kvajić G. , Brajović V.
Published: April 2011

Formation of a preferred texture in the unidirectional growth of polycrystalline ice from impure melt is governed by constitutional supercooling and "fast" kinetics of solidification in directions of the basal plane. The encroachment of crystals with vertical C axis (Cv grains) by the others takes place immediately by a mechanism of "fast" kinetics and/or by a lateral growth via nucleation of new basal platelets in a constitutionally supercooled melt. The first mechanism is expected to be much faster in eliminating the Cv grains than the second, which explains the peculiar presence of some Cv crystals at relatively large ice thicknesses.
Form Factors for Graviton–Particle Interactions
Authors: Hare M. G.
Published: April 2011

Contributions to the mass-energy form factors are calculated for the graviton–nucleon and graviton–deuteron (singlet and triplet) vertex interactions using sidewise dispersion relations. These factors are useful in astrophysics for vertex corrections to graviton–particle interactions. Electromagnetic contributions are considered for all vertices, π-meson contributions for the nucleon vertex and the two nucleon breakup for the singlet deuteron vertex. The deuterons are treated as elementary particles and the threshold region is assumed to dominate the results.
Impact Parameter Representation of the Scattering Amplitude
Authors: Razavy M.
Published: April 2011

From the Lippmann–Schwinger equation, the exact and different approximate relations for the impact parameter form of the total scattering amplitude on- and off-the-energy shell are derived. The relation between the impact parameter phase shift and the range of potential is studied, and several methods of determining the potential from the impact parameter phase shift for local, nonlocal, and energy dependent interactions are obtained in Blankenbecler and Goldberger's approximation. By considering solvable examples it is shown that the Glauber's approximation, in certain cases, may be valid for all scattering angles. Finally for completely elastic scattering or for a purely absorptive potential, methods of finding the impact parameter phase shift from the differential cross section for scattering are given.
Nuclear Matter Properties for the Reid, Bressel–Kerman–Rouben, and Hamada–Johnston Potentials
Authors: Banerjee P. K. , Sprung Donald W. L.
Published: April 2011

Nuclear matter calculations have been carried out for the Reid, Hamada–Johnston, and Bressel–Kerman–Rouben potentials. The convergence of the reference spectrum series for the G matrix is investigated, as is the approximation of choosing an average center of mass momentum. Higher-order cluster contributions are estimated from the scaling formulas of Day. The Reid potential predicts saturation at kF = 1.49 fm−1, with a binding energy −13.7 ± 1.5 MeV per particle.
Experimental Limits on the Translational Absorption in Inert Gas Mixtures near 1 cm−1
Authors: Muc A. M. , Reesor G. E. , Dagg I. R.
Published: April 2011

The experimental method and results of an attempt to make a direct measurement of the pressure-induced translational absorption are described. Measurements were made on He–A and Ne–A mixtures at pressures up to 2500 p.s.i.g. at a frequency of about 33 GHz (1 cm−1). The results establish an upper limit to the values of the absorption coefficients in this frequency region. The values are consistent with the values calculated from theory and infrared measurements if the anti-correlated collision approximation is used.
Low Frequency Raman Spectra of α-16O2, α-18O2, and α-N2
Authors: Mathai P. M. , Allin Elizabeth J.
Published: April 2011

The low frequency Raman spectra of the 16O2 and 18O2 isotopes of oxygen have been compared in the α phase of the solid. The frequency of the line at 27 cm−1 is the same in both isotopes and this confirms its interpretation as due to spin wave or magnon excitation. The libron frequencies are lower in the 18O2 than in the 16O2 spectrum. The integrated relative intensity of the libron lines is smaller in the 18O2 spectrum.The observed α-N2 spectrum confirms that reported by Anderson et al. The frequencies of the lines decrease and their half-widths increase as the temperature is raised to the α–β transition.
Quenching and Depolarization of Mercury Resonance Radiation
Authors: Deech J. S. , Pitre J. , Krause L.
Published: April 2011

The quenching and depolarization of mercury resonance radiation (2537 Å), induced in collisions of Hg(63P1) atoms with various molecules has been investigated using the method of delayed coincidences. The following total quenching cross sections have been obtained for the process Hg(63P1) → Hg(63P0, 61S0): Hg–H2, 24.6 Å2; Hg–D2, 22.7 Å2; Hg–CO, 21.7 Å2; Hg–CO2, 10.2 Å2; Hg–O2, 60.5 Å2; Hg–14N2, 0.73 Å2; Hg–15N2, 0.78 Å2; and Hg–Xe, < 0.002 Å2. A cross section of 267 Å2 has been measured for the depolarization of the resonance radiation by collisions with CO2 molecules.
Hydrodynamic Effects on the Laser-Beam Propagation through Gases
Authors: Rangnekar Sadanand S.
Published: April 2011

In this paper we study the hydrodynamic effects on the laser-beam propagation through gases. The equations of hydrodynamics and the equations of the ray path are solved numerically by using the finite difference scheme. The possibility of hydrodynamic and optical instabilities is eliminated by the choice of the von Neumann stability condition and by the proper distribution of the flux. Various tests are conducted to verify this. The technique is applied to study the problems of the possibility of hydrodynamic trapping of a laser beam, amplification of the acoustic waves, amplification of a modulated laser beam, and "banana" self-focusing. All these phenomena are theoretically found to exist. These phenomena can be explained in terms of the propagating pressure waves, induced initially by the incident beam and amplified as a result of their coupling to the radiation field.
Formation de O− de NO par Impact Electronique
Authors: Paquet C. , Marchand P. , Marmet P.
Published: April 2011

New measurements of the relative cross section of the dissociative attachment giving O− from NO in the range from 7 to 10 eV show new structures thanks to our smaller electron energy spread. New hypotheses are given to explain our results.
Plasma Edge Reflectance Measurements in GaxIn(1−x)As and InAsxSb(1−x) Alloys
Authors: Thomas Mathew B. , Woolley John C.
Published: April 2011

Room temperature measurements of plasma reflectance have been made on polycrystalline homogeneous n type samples of GaxIn(1−x) As and InAsxSb(1−x) alloys. An analysis for the case of general degeneracy in a Kane-type conduction band has been developed, to allow the determination of electron effective mass (m0*/m) at the bottom of the conduction band. Hence values of m0*/m vs. x have been determined for both alloy systems. From the experimental data, values of relaxation time and optical mobility have also been calculated.
Time Variation Study and Intensity Measurement for the Nearly Horizontal Cosmic Ray Muon Component
Authors: Hicks R. B. , Flint R. W. , Standil S.
Published: April 2011

A narrow angle cosmic ray particle telescope was operated at Winnipeg, Manitoba for a 2-year period commencing Oct. 16, 1967. The telescope was oriented East–West and was sensitive to muons at zenith angles in the range 86° to 90°. The data were analyzed for solar and sidereal time variations; the results are consistent with zero amplitude within the statistical accuracy of the experiment. An absolute intensity was calculated and is compared with previous measurements.
Spin and Parity Assignments in 77As
Authors: Long D. D. , Onega R. J. , Sauer R. C.
Published: April 2011

A directional correlation of the 0.56–0.63 MeV gamma rays following the beta decay of 77Ge was obtained. The spin of the 1.19 MeV level of 77As was determined as 7/2. Parity assignments were made on the basis of the mixing ratios of the observed correlation for the 0.63 and 1.19 MeV levels.
Ionic Conductivity of Potassium Bromide Crystals
Authors: Chandra Suresh , Rolfe John
Published: April 2011

The electrical conductivity of single crystals of potassium bromide was measured as a function of temperature, and as a function of the concentration of calcium bromide or potassium carbonate impurity. The results were analyzed on the assumption that the observed conductivity was due entirely to the motion of separated anion and cation vacancies (Schottky defects), with Coulomb interactions between charged defects. Agreement between measured and calculated conductivities at all temperatures showed that this assumption was reasonable. The values obtained for transport parameters were: Schottky-defect formation enthalpy hs = 2.53 eV, entropy Ss = 10.3k; positive ion vacancy migration enthalpy Δh1 = 0.65 eV, entropy Δs1 = 1.89k; negative ion vacancy migration enthalpy Δh2 = 1.22 eV, entropy Δs2 = 7.30k; association of calcium ions and positive ion vacancies enthalpy x = 0.61 eV, entropy η = 2.23k, where k is Boltzmann's constant.
Investigation of the Nuclear Stopping Mechanism by Heavy Particle Range Measurements in Isotopic Media
Authors: Leon J. , Steiger-Shafrir N. H.
Published: April 2011

An experimental study of the nuclear stopping mechanism has been carried out by performing high precision range and range straggling measurements of 96.5 keV 224Ra α-disintegration recoil particles in the following isotopic gases: H2/D2/T2,3He/4He, 14N2/15N2,16O2/18O2, and 20Ne/22Ne. Distinct range differences for light to heavy isotope mass ratios up to about 0.9 were determined. The results obtained establish clearly that the prediction of the isotope effect of the stopping medium, as derived from the Lindhard theory by using the power law potential as an approximation to the Thomas–Fermi potential, is to a good degree of accuracy, confirmed by experiment.
Optical Mixing in a Magnetized Plasma
Authors: Meyer J. , Stansfield B.
Published: April 2011

The nonlinear interactions of two electromagnetic waves resulting in the excitation of electrostatic oscillations in a magnetized homogeneous plasma are studied. A general expression for the spectral density of the induced fluctuations is derived which includes the effect of the ion motion and an externally applied uniform magnetic field. One basic assumption made is that the frequencies of the electromagnetic waves are much larger than any of the plasma resonance frequencies. Numerical calculations are carried out for the specific case where the induced k vector is parallel to the external magnetic field and the results are presented in a series of graphs. The effect of the ion motion for this case is discussed in detail. Some aspects of the case where the induced k vector is perpendicular to the magnetic field are also discussed. It is found that both—the ion motion and an external magnetic field—can significantly influence the spectral density of the fluctuations.
On the Electron Spin Resonance and Color in KCl and KCl(OH)
Authors: Papazian Harold A.
Published: April 2011

By adapting an optical system to a microwave cavity, simultaneous measurements of optical absorption and electron spin resonance have been carried out. It is demonstrated that the rate of change of spin density is different from the rate of change of color and that color may be obtained without concomitant electron spin resonance.
Corrélations dans l'Etat Fondamental de l'16O et Absorption Muonucléaire
Authors: Laverne A. , Goulard B. , Dang G. Do
Published: April 2011

The influence of 2 particle – 2 hole (2p–2h) configurations of the 16O ground state on the excitation probabilities of odd states in 16N by muon absorption has been studied.
Resonant Perturbation of Phonons in Cu(Au) Alloys Studied by Neutron Scattering
Authors: Svensson E. C. , Kamitakahara W. A.
Published: April 2011

The atomic vibrations in single crystals of Cu(Au) alloys containing 1, 3, and 9 at.% Au have been studied by means of neutron inelastic scattering. Measurements have been carried out for the [00ζ]T and [ζζ0]T1 branches of all three alloys and also for the [00ζ]L branch of the 9% alloy. In general, the impurity-induced widths, Γ, and the shifts, Δ, from the corresponding frequencies for pure copper exhibit definite resonance behavior. The detailed behavior of Δ and Γ as functions of frequency is, however, generally not in good agreement with calculations based on a mass-defect theory valid only for low impurity concentration. From the observed behavior of Δ and Γ for different branches and impurity concentrations, we conclude that, although the large mass change is undoubtedly the most important factor, force-constant changes and concentration effects also play important roles in determining the details of the resonance behavior in Cu(Au) alloys.
Transient Stimulated Thermal Scattering in Colored Liquids
Authors: Rangnekar S. S. , Enns R. H.
Published: April 2011

The results of a "small signal" theoretical treatment of the transient behavior of the stimulated thermal scattering of light by a small colored liquid sample are given. The analysis is applicable to an amplifier experimental set-up in which an undepleted pump beam and a small signal beam travel in opposite directions through the sample. In addition to reproducing features which have been previously predicted and experimentally confirmed, new features arise from terms which were neglected in previous analyses. For example, oscillatory behavior of the signal-beam gain factor can occur under certain conditions. It is also shown where the controversy of whether the Rayleigh lifetime τR or the Brillouin lifetime τB′ is the characteristic time for achieving steady-state stimulated thermal Brillouin scattering arises and how it is resolved.
Levels in 35Cl: Experimental
Authors: Wiesehahn W. J.
Published: April 2011

Decay schemes, angular distributions, and polarizations of gamma rays from the reaction34S(p,γ)35Cl have been measured. The lifetimes of some of the levels which were populated in these reactions have been measured. The four resonances excited by protons of 1020, 1214, 1267, and 1510 keV were studied. Spin and parity assignments for the 1220, 1762, 2645, 2695, 3006, 3163, 4058, 4174, 7355, 7545, 7601, and 7845 keV energy levels and the lifetimes of the first six of these are discussed.
Angular Distribution of Products from Photodissociation of Diatomic Molecules
Authors: Lin S. H. , Koizumi C. J.
Published: April 2011

The angular distribution of dissociation products in the photodissociation of diatomic molecules has been calculated quantum-mechanically. It is shown that in the adiabatic approximation the angular distribution of the electronic transition with the transition moment along the molecular axis can be expressed as σ(θ0) = (σ0/4π) [1 + βP2 (cos θ0)], and the angular distribution for the case of perpendicular transitions is very complicated and can be approximately expressed in the same form as that for the case of parallel transitions only in the limiting conditions. Approximate calculations of the angular distribution of photodissociation are also carried out by using the delta function approximation to the continuum radial wave functions, and it is found that in this approximation β = 2 for the parallel transition; that is, the angular distribution of dissociation products is of the form cos2 θ0.
Study of the (4–1) and (5–2) Hydroxyl Bands in the Night Airglow
Authors: Harrison A. W. , Evans W. F. J. , Llewellyn E. J.
Published: April 2011

A 1 year study of the (4–1) and (5–2) hydroxyl bands in the night airglow near 1 μ has revealed a non-uniform rotational temperature across the P branch of each band. The temperature increases with K′ value. There is a pronounced seasonal variation of temperature showing a summer minimum and winter maximum. The average measured brightness for the (4–1) band is 4.6 kR (winter) and 3.5 kR (summer), and for the (5–2) band is 5.8 kR (winter) and 4.3 kR (summer). It is shown that the time-averaged total band intensity fluctuations during a single night are quite large, sometimes a factor of 2, and are not definitely correlated with the rotational temperature during the same period.
Electrical Contacts and Conductivity of MoS2 Layer Structures
Authors: Souder A. , Brodie D. E.
Published: April 2011

The difficulty of making electrical contact to, and obtaining meaningful data from, strongly anisotropic layer structures is discussed and clarified for MoS2. An analysis of this anisotropy is presented and used to explain experimental results obtained from natural crystals of molybdenite.It is shown that annealed contacts on MoS2 make good electrical contact to the crystal by diffusing the contacting material parallel to the c axis and hence making contact to all of the layers. Just below room temperatures, activation energies [Formula: see text] parallel and [Formula: see text] perpendicular to the c axis are 0.04 to 0.08 eV but [Formula: see text] increases to between 0.08 and 0.12 eV below approximately 200 K, with [Formula: see text] at the low temperatures between 2 and 1.5 from sample to sample.The analysis is used to show that the published data for thick and thin crystals of MoTe2 can be made self-consistent.
Ram Effect in Sounding Rockets
Authors: Koehler J. A. , Kavadas A.
Published: April 2011

When a conducting body moves through a plasma, it collects charges. When the conductor has reached its floating potential the collection rates at the front and back differ and a current flows through the conductor. This "ram current" if measured may provide a simple way of determining the ambient ion density.The "ram current" is examined and the equations derived are used to calculate ion densities from a rocket flight.Simplifying assumptions and errors in the technique are discussed.
Thermoelectric Power of Pure Rhodium
Authors: Huntley D. J.
Published: April 2011

The thermoelectric power of rhodium has been measured between 4 and 300 K. A peak of +2 μV/K was found at 145 K and none at 25 K in contrast to results found by Carter et al. It is suggested that the 145 K peak may be a diffusion thermoelectric power peak recently predicted by Nielsen and Taylor.
Low-Energy Gamma-Ray Spectrum of 184m,184Re
Authors: Taylor H. W. , King J. D. , Singh B.
Published: April 2011

The gamma rays emitted by 184m,184Re with energies below 300 keV have been studied with a Si detector and a 4096-channel analyzer. The energies of several high-lying levels in 184W have been adjusted through the proper positioning of these gamma rays in the 184W level scheme.
Théorie du Maser au Rubidium 87
Authors: Tessier M. , Vanier J.
Published: April 2011

not available
Gravity-Induced Electric Fields in Metals
Authors: Leung M-C. , Papini G. , Rystephanick R. G.
Published: April 2011

Gravitational perturbations induce electric fields in metals by causing the lattice to deviate systematically from its periodic structure. In the microscopic approach used in this paper, the induced electric fields inside the metals are calculated from the periodicity deviations of the lattice. The results hold for weak stationary or quasi-stationary gravitational fields of permanent or nonpermanent nature. Explicit calculations are carried out for centrifugal and Lense–Thirring fields and for the gravitational field of the earth. In the latter case, size and direction of the electric field agree with those determined by Dessler et al. and lend support to the experimental results of Beams. The formalism used can also be applied to superconductors. It is found that the gravitational field introduces some anisotropic terms in the electron–phonon interaction.
Magnetic Domain Structure of Hematite
Authors: Eaton J. A. , Morrish A. H.
Published: April 2011

Magnetic colloid observations on synthetic hematite indicate the existence of only two phase domain structures. The normal or N structure is a usually slablike 180° wall structure where the majority of walls are parallel to the basal plane and have a 100–200 μm separation. Wall energies are estimated to be 0.35 × 10−1 to 1.0 × 10−1 erg/cm2 from domain geometry. Under special circumstances, a domain structure, called CN domains, occurs in [Formula: see text] and [Formula: see text] surfaces and appears to be a two phase structure of non-180° walls. Spontaneous magnetostriction requires these walls of 100–200 μm separation to be planar and lie either perpendicular to or at ~26° to the basal plane. A third structure, called C domains, of 25–50 μm spaced planar walls occurs on (110) surfaces in two characteristic directions symmetric with the basal plane and consistent with CN-wall geometry. However, because of their behavior and geometry, they appear to be nonmagnetically stabilized but possibly by a strain effect. By using magnetoelastic coupling for the effective basal plane anisotropy constant for moment rotation in domain walls, N-wall energies are estimated to be 0.45 × 10−1 to 1.0 × 10−1 erg/cm2. Because of geometry complications CN-wall energies are difficult to calculate but are estimated to be ~10−1 erg/cm2 or slightly larger.
The Band System of the CCO Molecule
Authors: Devillers C. , Ramsay D. A.
Published: April 2011

The transient absorption spectrum observed previously (Devillers) in the flash photolysis of carbon suboxide has been studied under high resolution in the region 5000 to 9000 Å and assigned to the CCO radical. A rotational analysis of the 000–000 band near 8580 Å shows conclusively that the electronic transition is [Formula: see text]. From molecular orbital considerations the lower state is assigned as [Formula: see text]. Short progressions involving the stretching vibrations (ν1′ = 0–3, ν3′ = 0–1) have been observed. A Fermi resonance has been found involving ν3′ and 2ν2′. Some sequence bands have been assigned; in particular the 010–010 sequence band clearly shows the Renner splittings expected for the Ã3Πi excited state. A band with a different type of rotational structure has been assigned to the forbidden component 010 3Σ(−) – 000 3Σ−. The rotational analysis of this band is in excellent agreement with the theory of Hougen for the rotational energy levels of a linear molecule in the ν2 = 1 level of a 3Π state.The following molecular constants have been obtained:[Formula: see text]
Rotational Energies of Linear Polyatomic Molecules in Vibrationally Degenerate Levels of Electronic 2Σ and 3Σ States
Authors: Merer A. J. , Allegretti J. M.
Published: April 2011

Formulas are developed to describe the rotational energy of a linear polyatomic molecule in a 2Σ or 3Σ electronic state, where one or more quanta of a degenerate bending vibration are excited. In 2Σ states the spin doubling and l-type doubling are independent, provided that the rotational constant B is large compared with the spin–rotation interaction constant γ. In 3Σ states the normal triplet splitting patterns (e.g. Schlapp's formulas) are considerably altered by the presence of vibrational angular momentum at low rotational quantum number N, especially when the spin–spin interaction parameter λ is sizeable; however, with increasing rotation, the normal spin and l-type doubling patterns are approached, as the vibrational angular momentum is progressively uncoupled from the molecular axis.
Spin-Wave Excitations in Erbium
Authors: Holden T. M. , Powell B. M. , Stringfellow M. W. , Woods A. D. B.
Published: April 2011

Neutron scattering by spin waves in erbium at 4.6 °K in its magnetic cone phase has been measured along the c axis and to a lesser extent along lines parallel to the a axis. The results, when combined with assumptions about the crystal field interactions, lead to the spin-wave dispersion relation and the Fourier transform of the exchange interaction. Inconsistencies which arise from the crystal field (anisotropy) considerations lead to the conclusion that the model Hamiltonian on which the analysis is based is inadequate.Measurements of the temperature dependence of the scattering have also been made. No well-defined spin-wave groups were observed in the more complex phase above 20 °K.
Spins of Levels in 32P by Angular-Correlation Studies
Authors: St-Pierre C. , Gagnon R. , Gill G. S.
Published: April 2011

The spectroscopic properties of the 1.75, 2.66, 2.74, and 3.00 MeV levels of 32P have been studied by the particle–gamma angular-correlation method II of Litherland and Ferguson applied to the reaction 29Si(α,p)32P at 10.3 MeV. The decay scheme was observed with a Ge–Li detector in coincidence with the protons. The spin of the 1.75 MeV level was determined to be 3. The restrictions imposed on J by the analysis of the angular correlations combined with other information lead to the following most probable assignments: 2.66 MeV, J = 1,2; 2.74 MeV, J = 1,2; 3.00 MeV, J = 1,2,3.
Experimental Study of Scattering of Electromagnetic Waves by Radially Inhomogeneous Cylinders
Authors: Parkinson R. G. , Kharadly M. M. Z.
Published: April 2011

Scattering by radially inhomogeneous isotropic cylinders was investigated experimentally in the case of parallel polarization. The cylinders used were constructed of a type of artificial dielectric which made the simulation of a smooth permittivity variation possible. The measurements were carried out in a parallel-plate region for both plane- and cylindrical-wave incidence. The scattered-field coefficients were computed from measured field values by applying a Fourier least-squares fit. The scattered field and back-scattering cross-section computed using these coefficients were compared with those expected from theory.
Lattice Dynamics and Short Range Correlations in B.C.C. 3He
Authors: Glyde H. R. , Khanna F. C.
Published: April 2011

A T-matrix method for determining the effective potential appropriate to the correlated Gaussian functions employed in lattice dynamics is developed. The method is similar to those discussed by Guyer and Horner for single particle functions. The T matrix and the correlated functions are then computed iteratively, much as suggested for the Brueckner–Hartree–Fock method for nuclear matter, to obtain an internally consistent result. Employing the T matrix, phonon dispersion curves, elastic constants, and Debye temperatures which include the cubic anharmonic term are calculated. The cubic contribution is larger for the T matrix than for the Nosanow effective potential and this leads to upward curvature of the T2[110] phonon branch, as noted by Horner, and thus a possible explanation of the anomalous Debye temperature observed at low temperatures. No resolvable second peaks in the scattering response functions were found.
Magnetic Susceptibility and Electrical Resistivity of Dilute Chromium–Titanium Alloys
Authors: Chiu C. H. , Jericho M. H. , March R. H.
Published: April 2011

We report measurements of the magnetic susceptibility and the electrical resistivity of chromium–titanium alloys containing Ti concentrations of up to 0.6 at.%. The measurements were performed between 320 and 4.2 K. A very rapid depression of both the Néel temperature and the spin-flip temperature on alloying was observed. The paramagnetic susceptibility of pure chromium and the alloys displayed a linear temperature dependence and it is suggested that thermal expansion effects might be responsible for this linear temperature dependence. The analysis of the electrical resistivity results points to the existence of an extra electron scattering mechanism above TN in pure chromium as well as the dilute alloys.
Absorption Spectrum of Si2 in the Visible and Near-Ultraviolet Region
Authors: Dubois I. , Leclercq H.
Published: April 2011

A very strong absorption spectrum of Si2 has been observed between 4800 and 3000 Å, yielding new data on the first excited electronic states of this molecule.
Limits to the Accuracy of the Cohen–Feldmann Bounds on Eigenvalues of Hermitian Operators
Authors: Hayes Dallas T.
Published: April 2011

Proof is given that when the Eckart estimate to the overlap integral is used in the Cohen–Feldmann lower bound on the eigenvalue of a Hermitian operator, the only self-consistent bound which can be obtained is that of Temple–Kato. It is pointed out that a similar situation holds for the Stevenson–Crawford bounds.
Distribution de la Somme des Photoélectrons Détectés en L Points sous Eclairement Gaussien Partiellement Cohérent
Authors: Bures Jacques , Delisle Claude , Zardecki Andrzej
Published: April 2011

The analysis of the photocount distribution in incoherent Gaussian light detected in L space points of a photodetector is extended to the case of partially coherent light. The second moment of the derived distribution is exact. A function η is introduced which accounts for the spatial coherence aspect of light as does the function ξ, (Mandel) for the temporal coherence aspect. A more general function ζ, which for cross-spectrally pure light reduces to the product ζ = ηξ, depends on both spatial and temporal characteristics of coherence. It is shown both theoretically and experimentally that many different geometrical configurations yield the same normalized second moment. A pseudo-thermal source [Formula: see text] where T is the detection time and Tc the coherence time) is used for the experimental verification.
Inversion of Microwave Scattering Patterns
Authors: Fedotowsky A. , Boivin G. , Tremblay R.
Published: April 2011

An inversion method which reproduces the radial variation of dielectric constant in a dielectric target from its microwave scattering pattern is presented. Inversion criteria are developed showing what part of the target can be reconstructed. The technique is applied to experimentally measured scattering patterns.
Debye Temperatures of Alkali Halides
Authors: Konti A. , Varshni Y. P.
Published: April 2011

Four high precision methods are employed to calculate the Debye temperatures of alkali halides. The results obtained by the four methods are compared among themselves and with the experimental data.
Tunneling into Weakly Coupled Copper and Lead in Proximity
Authors: Vrba J. , Woods S. B.
Published: April 2011

Tunneling experiments from superconducting Al base electrodes into both sides of weakly coupled Pb–Cu proximity sandwiches have been performed. The temperature variation and energy of multiple-peaked structure in the normalized tunneling conductance curves compare very well with those calculated using the McMillan tunneling model of the proximity effect, although the calculated curves exhibit more sharply peaked structure than the observed ones. A simple model which takes into consideration the thickness inhomogeneities in the proximity sandwich is proposed in order to account for the sharpness differences.
Electric Field Near an Accelerating Copper Tube
Authors: Guptill Ernest W.
Published: April 2011

The electric fields arising from (1) nonuniform strains and (2) the inertial mass of the electron (Schiff–Barnhill field) have been measured. In both measurements the sample was a 15 ft copper tube which underwent accelerations ranging from 5 m/s2 to 50 m/s2. Expressed in terms of the acceleration, g, and the ionic mass, M, the first was found to be 0.10 Mg/e and the second 1.0 mg/e where m is the electron mass. The accuracies are 10% and 5% respectively.
Effect of Lattice Relaxation on the Soft X-Ray Spectra of Metals
Authors: Bergersen B. , McMullen T. , Carbotte J. P.
Published: April 2011

The effect of relaxation of the lattice around the core hole on the soft X-ray spectra of metals near the Fermi edge, with particular application to Li and Na, is investigated. Neglecting lifetime effects, linearizing the core-hole phonon coupling and making a harmonic approximation for the phonons, the problem is exactly solvable by a generalization of a method previously proposed by Langreth to finite temperatures. Numerical calculations are carried out within the framework of linear response theory using the Thomas–Fermi, R.P.A., and Singwi et al. dielectric functions, and realistic phonon spectra obtained from neutron inelastic scattering data. The calculations give rise to lattice relaxation effects of similar magnitude in both metals. The results are considerably smaller than would be necessary to explain the shape of the Li spectra (contrary to a previous suggestion), while in Na the contribution is calculated to be of the same order of magnitude, but with a different temperature dependence, than the other factors influencing the shape of the absorption edge.
Collective States in 151Sm
Authors: Nelson D. E. , Burke D. G. , Cook W. B. , Waddington J. C.
Published: April 2011

Inelastic deuteron scattering experiments with a target of 151Sm have been carried out with bombarding energies of 5 MeV and 12 MeV. The scattered deuterons were analyzed with a magnetic spectrograph and B(E2) values for the states populated were extracted from the ratios of inelastic to elastic cross sections. The gamma rays following Coulomb excitation of 151Sm by 50 MeV 35Cl ions were also studied with Ge(Li) detectors. Levels at 65.8 keV, 168.4 keV, and 295.1 keV were populated with B(E2) values of 0.80 e2(barn)2, 0.15 e2(barn)2, and 0.46 e2(barn)2 respectively. If it is assumed that the strong-coupling model is appropriate and that the level at 65.8 keV is the first excited member of a rotational band based on the I = 5/2 ground state, the measured B(E2) value corresponds to a deformation of β = 0.21. It must be noted, however, that the observed states do not satisfy the properties expected for a well-ordered ground-state rotational band.
Emission Spectrum of the PO Molecule. Part II.2Σ–2Σ Transitions
Authors: Verma R. D. , Dixit M. N. , Jois S. S. , Nagaraj S. , Singhal S. R.
Published: April 2011

Rotational structure of emission bands of the PO molecule in the region 5300–3800 Å is analyzed. The spectrum is attributed to 5 electronic transitions A2Σ+–B2Σ+, F2Σ+–B2Σ+, G2Σ+–B2Σ+, H2Σ+–B2Σ+, and I2Σ+–B2Σ+, where F, G, H, and I are the new electronic states and A and B are the upper states of the well-known γ and β bands respectively. Practically all the new 2Σ states are found to be perturbed. A qualitative account of these perturbations together with a deperturbation of certain levels is given. A number of cases of predissociation are also observed. This predissociation is attributed to the presence of 4Πi, and A′2Σ+ states, which dissociate to the ground state atomic products. From this an upper limit of the dissociation energy of the ground state of PO is determined to be D0 = 49 536 cm−1. The A, D, E, G, H, and I states of this molecule are assigned as Rydberg states corresponding to the σ4s, π4p, δ3d, σ4p, σ3d, and σ5s orbitals, respectively. From them a value of 67 570 cm−1 is evaluated for the first ionization potential of PO. All the electronic states established for this molecule are described in terms of electron configurations.