bluuebunny/crossref_metadata_2025 huggingface dataset:
Transition Strengths of Analogue States in A = 18 Nuclei
Authors: Rolfs C.
Published: April 2011

A search for the 3061 (2+, T = 1) → 1041 (0+, T = 1) keV γ-ray branch in 18F has been performed with the use of the capture reactions 14N(α,γ)18F at Ea = 1526 keV and 17O(p,γ)18F at EP = 741 keV. The observed branching ratio is 0.11 ± 0.03%. The mean life of the 3061 keV state was found to be < 1.5 fs. This E2 branch in 18F is compared with the analogue transitions in 18O and 18Ne as well as with shell model calculations.
Nouvelles Transitions Electroniques Attribuées à la Molécule LuH
Authors: d'Incan J. , Effantin C. , Bacis R.
Published: April 2011

Two electronic band systems, lying approximately at 4200 and 5000 Å, have been attributed to a new molecule LuH. They correspond to 1Π–X1Σ and 1Σ–X1Σ transitions. The vibrational and rotational analysis of the (0–0) and (1–1) bands of these two systems lead to the determination of the molecular constants of the fundamental X1Σ. and excited 1Π and 1Σ states.
The Intensities of the Infrared-Active Intermolecular Translational Bands in Solid Chlorine. Evidence for Intermolecular Bonding
Authors: Wong P. T. T. , Whalley E.
Published: April 2011

The intensity of absorption of the translational lattice vibrations of crystalline chlorine at ~90 °K has been measured. It is about 35 times that calculated assuming that the oscillating moments are induced by the quadrupole moments of neighboring molecules. This provides strong evidence for intermolecular bonding between chlorine molecules.
Impact Parameter Representations
Authors: Kamal A. N.
Published: April 2011

A discussion of the Glauber and Blankenbecler–Goldberger impact parameter representation for the scattering amplitude is presented with emphasis on the wave function approach. The treatment makes clear the relationship between the approximations made to derive either of the two amplitudes. Both on-energy-shell and off-energy-shell scatterings are treated. A derivation of the two representations in momentum space is presented bringing out the relationship between the approximations in a coordinate space treatment and the momentum space treatment.
Helium Quench Radiation and Transition Polarizability
Authors: Drake G. W. F.
Published: April 2011

An accurate calculation of the quenching rate for metastable singlet helium atoms and helium-like ions in a constant electric field is presented. The theoretical rate for helium is (0.932 ± 0.001)F2 s−1, where F is the field strength in kV/cm, in agreement with the recent experimental value (0.926 ± 0.02)F2 s−1.In addition, several oscillator strength sums are evaluated, along with the static and transition dipole polarizabilities of the 1 1S, 2 1S, and 2 3S states for the helium-like ions up to Ne IX.
Surface-Induced Vectorial Optical Properties of Liquid Mercury
Authors: Crozier E. D. , Murphy E.
Published: April 2011

In an attempt to clarify the origin of the pronounced difference between the ellipsometry and reflectivity deduced dielectric constants of liquid mercury, ellipsometry and reflectivity measurements have been made simultaneously over the wavelength range 2500 to 7500 Å for the same samples for the same angle of incidence. Ellipsometry results on a free mercury surface extend the reported range from 4000 to 2500 Å and confirm the established deviation of ellipsometry results from Drude behavior. In the case of a silica–mercury interface, Rs agrees with that calculated from the Drude model while Rp does not. Both ellipsometry and reflectivity dielectric constants are similar to the vacuum–mercury interface results. In the case of a borosilicate–mercury interface, both Rs, and Rp are non-Drude with the reflectivity dielectric constants being appreciably lower, and the ellipsometry values higher, than the Drude values. It is concluded that the optical properties of mercury are vectorial, being different for P and S polarizations, and cannot be specified by the dielectric constant for an isotropic, homogeneous medium. Calculations have shown that the vectorial optical properties of liquid mercury for a silica–mercury interface are consistent with the existence of a surface transition layer similar to that first proposed by Bloch and Rice.
Analyse Rotationnelle des Etats C2Δ et D2Σ− de AsO: Perturbations de l'Etat C
Authors: Goure J. P. , Figuet J. , Massot J. N. , d'Incan J.
Published: April 2011

Rotational analysis of several subbands of the C2Δ (a) → X2Π (a) system of the AsO radical show five perturbations in the v = 0, 1, 2, and 3 levels of the C state. Three perturbations are due to components of a new state, probably 2Δ (a) or 2Φ (a). The deperturbed constants of this new state and of the C state are extracted from the experimental data. Constants are also given for two upper vibrational states of the D2Σ− → X2Π (a) transition which overlaps the C → X system.
Decay of 101Mo and 101Tc
Authors: Cook W. B. , Johns M. W.
Published: April 2011

The energy levels of 101Tc and 101Ru have been investigated through a study of the decays of 14.6 min 101Mo and 14.0 min 101Tc. Singles gamma-ray spectra were obtained with high-resolution Ge(Li) detectors having volumes of 0.8 cm3 and 12 cm3. A 36 cm3 Ge(Li)–40 cm3 Ge(Li) coincidence spectrometer operated in a two-parameter configuration (4096 × 4096) was employed in collecting coincidence data. More than 180 gamma transitions have been observed in the two decays: 152 are definitely assigned to the decay of 101Mo, 25 to the decay of 101Tc. These gamma rays have been incorporated into level schemes involving 45 levels in 101Tc and 10 levels in 101Ru. On the basis of beta and gamma selection rules, spin–parity assignments have been suggested for many of the levels.
Bulk Modulus in Polycrystalline Inert Gas Solids at 0 K
Authors: Aziz R. A. , Bowman D. H. , Lim C. C.
Published: April 2011

Bulk modulus values in the inert gas solids at 0 K are of interest because they may be compared with theoretical estimates based on assumed models of the solid. Various methods have been used to estimate the 0 K bulk modulus B(0) from experimental data. In this paper we propose a new method for estimating B(0) which is based on the empirical observation that saturated liquid phase sound velocities, when extrapolated linearly in density to 0 K solid density, give results agreeing with the best solid phase measurements.
Exchange Degeneracy and Duality in a Generalized Interference Model
Authors: Logan R. K.
Published: April 2011

We consider a generalized interference model in which the Pomeron and the other Regge poles are built in the sense of a FESR bootstrap from both the resonance and background part of the low energy scattering amplitude. We develop a test of strong exchange degeneracy on the background part of the low energy scattering amplitude through the use of FESR. We show that the restrictions through FESR imposed by exchange degeneracy are weaker than those of duality. Finally, we are able to relate the amount of duality breaking in [Formula: see text] in the absence of exotic mesons to the ratio of NN or πN, P′, and ρ Regge residues.
Studies on a Microwave Dragging Technique for Measuring Electron Drift Velocity
Authors: Gray R. B. , Makios V.
Published: April 2011

The measurement of electron drift velocity in a low pressure gas discharge, by a microwave analogue to Fizeau's dragging experiment, is considered. The technique involves the measurement of the phase difference between two electromagnetic waves at microwave frequencies, propagating in opposite directions through the discharge, and relating this phase difference to the electron drift velocity in the discharge. A model is developed which provides this relationship and some phase differences are computed for several situations of interest. It is shown that the dragging effect can be quite large if the plasma is magnetized. In particular, the use of the right-hand circularly polarized wave appears appropriate for electron drift velocity measurement in a longitudinally, magnetized gas discharge.
Further Study of the Anomalous Behavior of Secondary Particles Emitted from Heavy Primary Interactions
Authors: Judek B.
Published: April 2011

Interaction lengths of singly charged relativistic secondary particles emitted from interactions of very heavy cosmic ray nuclei in emulsions were measured by systematic following of their tracks through the stack. The primary energies were determined by the "knock on" electron method. The results show that particles from interactions with primary energies between 1 and 5 GeV/nucleon emitted in the angular interval [Formula: see text] (θev is the expected RMS angle for evaporation protons) have significantly shorter mean free paths. The variation of the observed mean free paths with distance from the primary interactions shows a transition from short to normal interaction lengths at about 3 cm which indicates the presence of some anomalous component interacting with a very short mean free path of a few cm and relative intensity of order of 10%. This result cannot be accounted for by any known particle or interaction. Considerations of emission angles and types of stars produced by the secondary particles lead to a tentative conclusion that particles exhibiting the anomalously short interaction lengths are scattered fragments of the incident nuclei.
A Study of the (d,p) Reaction on 62Ni near the Coulomb Barrier
Authors: Sykes D. , Ramavataram K. , Mercier G. F. , St-Pierre C. , Yang C. S.
Published: April 2011

The absolute differential cross sections for the 62Ni(d,p)63Ni reaction have been measured at deuteron bombarding energies of 4.45 and 5.12 MeV. Spectroscopic factors were obtained and the results are discussed in terms of the DWBA model of stripping reactions. It is found that this technique leads to reliable and stable values of the spectroscopic factor even for states which carry less than half the single particle strength.
Effect of Capacitance on Gain in a Transversely Pulsed CO2 Discharge
Authors: Robinson A. M.
Published: April 2011

The small signal gain of a transversely pulsed high pressure CO2 discharge has been measured as a function of the discharge driving capacitance. The gain was observed to first increase and then decrease with capacitance for the 3 gas mixes investigated. The decrease in gain is caused by heating of the gas and a degradation of the discharge from a pulsed glow to an arc discharge. The duration of the gain pulse decreased with capacitance and for a 60:0:40 CO2:He:N2 mix an absorption of up to 30% over 27 cm was observed following the gain pulse. The results of calculation of the expected temperature increase of the gas were consistent with the observed absorption. The fraction of the electrical energy distributed between the electrode ballast resistors and the amplifier discharge was constant with respect to capacitance but varied approximately inversely with gas pressure.
Quadratic Zeeman Effect of Donor Lines in Silicon. II. Comparison with Experiment
Authors: Pajot B. , Merlet F. , Taravella G.
Published: April 2011

The Zeeman effect in the photoexcitation spectrum of phosphorus in silicon has been studied up to 64 kG in the Faraday configuration with the field parallel to the three principal axes of the crystal. In this work, we have observed a slight decrease of the transverse effective mass with the field and we found a fair agreement between theory and experiment for the 2p± and 3p± levels. Better agreement is obtained, however, if the variation of the effective Bohr radii with the magnetic field is taken into account. For the 2p0 and 3p0 levels, the variation of the effective Bohr radius [Formula: see text] alone cannot be observed experimentally in the Faraday configuration, but our results indicate a much more important decrease than for the p± levels and a variational calculation is necessary in this case. The shift of the 2p0 and 3p0 lines obeys roughly the n2(n2 − 1) relation, which should not be observed in the case of strong interactions with upper levels.
Interferometric Measurements of Isotherms of Sulfur Hexafluoride in the Critical Region
Authors: Balzarini David A.
Published: April 2011

Isotherms of sulfur hexafluoride in the critical region have been determined by interferometric measurements. A thin sample of pure fluid, compressed under its own weight, is placed in one arm of a Mach–Zehnder interferometer. The resulting interference pattern produced in the image plane of a lens yields horizontal fringes which relate fluid density to height in the sample. Isotherms giving density versus chemical potential or pressure are obtained from analysis of the interference patterns. Six sulfur hexafluoride isotherms for temperatures between 0.0018 K and 0.0281 K above the critical temperature are plotted.
Alternating Current Conductivity in MoS2 Layer Structures
Authors: Souder A. D. , Brodie D. E.
Published: April 2011

The electrical properties of semiconducting layer structures are analyzed in terms of a model which accounts for the capacitive coupling between layers at high frequencies. Electrical activation energies for the conductivity measured parallel and perpendicular to the c axis are obtained for natural crystals of MoS2 from measurements in the high and low frequency limit using a single set of contacts on one face of the semiconductor. Adhesive tape support and epoxy encapsulation minimize crystal handling and possible crystal damage.
Born Cross Sections for the Excitation of Helium by Fast Protons
Authors: Ojha S. P. , Tiwari P. , Rai D. K.
Published: April 2011

Cross sections for excitation of helium by proton impact have been calculated in the Born approximation. Transitions from the ground state to the n1P(n = 2 and 3) states have been considered. Highly accurate wave functions of the Hartree–Fock and configuration-interaction type have been used to represent the ground state. Approximate wave functions due to Messmer have been employed for the final states. The results are compared with other calculations and with experiments.
Elastic Waves Originating at the Surface of a Spherical Opening in Nonhomogeneous Isotropic Media
Authors: Moodie T. Bryant
Published: April 2011

This paper is concerned with the propagation of three-dimensional waves in nonhomogeneous isotropic elastic media. Herein we develop a formal method for the solution of the linearized equations of elasticity for nonhomogeneous media whose properties depend continuously on the radial distance from a point. The method is developed for the equations of motion formulated in terms of displacements, velocities, and stresses. It is based on a method developed by Karal and Keller for the asymptotic solution of the linearized equations of elasticity formulated in terms of displacements and displacement potentials, and is a generalization of results obtained for the one-dimensional case by Cooper and for the two-dimensional case by the author.The method is applied to the propagation of dilatational waves generated by a radial input velocity in the form of a unit function applied to the surface of the hole in a medium whose properties depend on the radial distance from the center of the hole according to a general law. Also, we apply the method to the propagation of purely distortional waves generated by a stress applied at the hole and corresponding to a tangential impulse symmetrical about a diameter of the hole.
Photon Correlation Spectroscopy Using a Digital PDP-9 Computer
Authors: Hallett F. R. , Gray A. L. , Rybakowski A. , Hunt J. L. , Stevens J. R.
Published: April 2011

Photon correlation spectroscopy has recently been shown to be a fast and accurate method of measuring the translational diffusion constant (D) of macromolecules. The measurement time is so low that it is possible to follow changes in the diffusion constant as a function of temperature, pH, etc. Most of the photon correlators in existence employ an electronic autocorrelator which relies on a clipping process to construct the desired functions. The spectrometer which we describe here is on-line to a Digital PDP-9 computer which is programmed to carry out a complete correlation analysis. Advantages and disadvantages of this technique are discussed.
Dielectric Loss Measurements on Nonpolar Liquids in the Microwave Region from 18 to 37 GHz
Authors: Dagg I. R. , Reesor G. E.
Published: April 2011

The results of dielectric-constant measurements on a number of low-loss liquids in the microwave frequency region from 18 to 40 GHz are presented. Emphasis is placed on the value of the loss tangent. Liquids measured include carbon tetrachloride, carbon disulfide, cyclohexane, n-hexane, n-heptane, n-nonane, and n-decane. A wave guide method was used giving an accuracy for the loss tangent of ±0.3 × 10−4. Where possible, results have been fitted to a Debye expression. Comparisons have been made with available results of other workers.
Experimental Measurement of the Photodetachment Cross Section
Authors: Burt J. A.
Published: April 2011

The cross section for photodetachment of the [Formula: see text] ion has been measured at a pressure of 3 Torr in a flowing weak plasma. A differentially pumped quadrupole mass spectrometer was used to identify the ion and detect photodetachment.
Inner Shell Vacancy Creation in the Beta Decays of 147Pm and 185W
Authors: Campbell J. L. , Law J.
Published: April 2011

K- and L-shell auto-ionization probabilities have been measured for the beta decays of 147Pm and 185W by Ge(Li) and Si(Li) spectroscopy techniques that eliminate electron detection. The results obtained are in good agreement with values calculated from a model based on vacancy creation mechanisms of shake-off and shake-up and employing a simple correction for direct collisions.
On the Classical Origin of Dirac-Like Wave Equations
Authors: Rafanelli Kenneth
Published: April 2011

We investigate the group structure of the intrinsic dynamical variables describing the relativistic motions of the classical pure gyroscope. It is shown that the 10 elements of this group, the 6 components of the spin angular momentum tensor, and the four-velocity components have Poisson bracket relations among themselves characteristic of the Lie algebra of the De Sitter group. This algebraic result allows a complete description of the free particle motions to be deduced from a proper-time Hamiltonian linear in the four-momentum components. Thus we are led, via the correspondence principle, to a classical understanding of the origin of the algebraic and dynamical properties characteristic of Dirac-like relativistic wave equations.
Structure and Electrical Conductivity of Amorphous ZnTe and CdTe
Authors: Brown H. M. , Brodie D. E.
Published: April 2011

Amorphous films of ZnTe and CdTe have been prepared and studied. Electron microscope studies have shown the films to have crystallite diameters of about 25 Å. A radial distribution analysis of the electron diffraction data for ZnTe shows that the first and second nearest neighbor distances are the same as in the bulk crystal and they are consistent with the basic crystalline tetrahedral units being retained in the amorphous phase.The electrical conductivity of ZnTe films has a temperature dependence which varies with the annealing temperature. This is explained by assuming that the extrinsic range is caused by acceptor-like dangling bonds which anneal at lower temperatures (100 °C), but that at higher temperature anneals (400 °C) the film re-crystallizes.
Study of Single Crystals of Magnesium and Zinc by Positron Annihilation
Authors: Becker E. H. , Senicki E. M. D. , Gould A. G. , Hogg B. G.
Published: April 2011

A point geometry positron annihilation angular correlation apparatus has been used to study oriented single crystals of magnesium and zinc. The results are compared with the theoretical predictions obtained from a simple picture of the electronic wave functions combined with two models for the positron wave function. The agreement between theory and experiment is considerably improved in the case of magnesium by the use of an enhancement factor.
Far-Infrared Absorption in Bulk Samples of Superconducting d-h.c.p. Lanthanum
Authors: Kry L. W. , Hemming D.
Published: April 2011

Far-infrared absorption measurements have been made on bulk samples of d-h.c.p. lanthanum and the results indicate a gap width, 2Δ, of 11.6 ± 0.3 cm−1 or 1.44 ± 0.04 meV. Using a value of Tc = 4.87 ± 0.02 °K, taken from the literature, this gives 2Δ = (3.43 ± 0.09)kTc.
Photoconductivité Extrinsèque dans le GaAs
Authors: Prat F. , Fortin E.
Published: April 2011

The photoconductivity of Cr-doped GaAs has been studied between 0.75 and 6 μ with particular emphasis on long term effects and quenching at 80 K. Hall mobility measurements were also performed under various conditions of illumination. It is shown that extrinsic photoconductivity spectra of compensated materials must be interpreted with caution.
Microscopic Theory of Tunneling Anomalies. Hamann's Approximation
Authors: Howard Mike , Nagi A. D. Singh
Published: April 2011

We have calculated the values of the conductance for a normal metal tunneling junction containing a single localized paramagnetic state near the metal–oxide interface. Our method is similar to that used by Appelbaum et al. We confine our calculations to T = 0 °K and [Formula: see text] Kondo temperature. We use Hamann's solution for the l matrix and compare our results with those obtained by Appelbaum et al. who use Nagaoka's solution for the l matrix.
Etat Stationnaire dans des Plasmas CO2–N2, CO2-He et CO2–N2–He Produits par Décharge Electrique
Authors: Bailly D. , Gaultier D. , Rossetti C. , Barchewitz P.
Published: April 2011

Small signal gain coefficients in a flowing amplifying mixture of CO2–N2, CO2–He, CO2–N2–He at different partial pressures have been measured for several individual rotation–vibration transitions in the P and R branches of the 00°1–10°0 band of CO2. These gain measurements have been done using a single line, single mode laser; the power stability of this laser is better than 1.5 × 10−2 during 1 h. If we assume a Boltzmann distribution of population among the rotational levels characterized by a temperature TR not in equilibrium with the translational motion of the gas, we can calculate the populations of the lower and upper laser levels and the rotational temperature for several CO2–N2, CO2–He, CO2–N2–He mixtures. The calculations show that N2 and He have a very different action on the populations and on the rotational and translational temperatures.The vibrational temperatures for the mixtures have been calculated using a model proposed by Moore et al.
Stretching of Spacetime
Authors: Rastall Peter
Published: April 2011

A class of pseudo-Riemannian manifolds is considered for which the metric is [Formula: see text], where χ and f are functions, [Formula: see text] is a flat metric, and [Formula: see text] is a cotangent field. The observed behavior of planets and electromagnetic waves is compatible with a special form of this metric. A number of possible field equations are discussed. Weber's observations of oscillations in the gravitational field are compatible with the metric only if the oscillations are not wavelike.
Wavelike Structure of Magnetic Field-Aligned Irregularities Detected by Phase Interferometry
Authors: Hajkowicz L. A.
Published: April 2011

Recordings of scintillations in the angle of arrival of satellite beacon transmissions at 136.410 MHz, by means of a modified phase interferometer, show relatively slow, periodic increases in angular variations. These increases are associated with occurrences of magnetic field-aligned irregularities at the height of the F region. The periodic component of scintillations is thought to arise from a wavelike form of distribution of irregularities. The wavelength most frequently found is in a 3–4 km range. No similar wave structure was found in simultaneous recordings of amplitude scintillations, possibly because of the difference between amplitude and phase scale sizes of irregularities. The existence of magnetic field-aligned irregularities, characterized by the periodic angular structure, could be evidence of a ducted mode of propagation of hydromagnetic waves originating in the auroral zone.
Foreign-Gas-Broadening Effects in the 15 μm CO2 Bands
Authors: Reichle Jr. Henry G. , Young Charles
Published: April 2011

The effects of N2, O2 Ar, and He on the absorption of radiation by the 15 μm perpendicular CO2 bands are reported. The investigation was carried out at medium resolution and at gas pressures less than 1 atm. The results of the study are presented in the form of a band-averaged broadening coefficient for N2, band-averaged broadening factors for O2 Ar, and He, and wavelength dependent broadening coefficients for N2, O2 Ar, and He. Comparisons are made with other experimental and theoretical results. In addition transmittances were calculated for homogeneous paths using some of the molecular parameters determined in the study and compared with measured transmittances. The agreement was reasonably satisfactory and revised values for the intensities of some of the 15 μm bands are presented.
11B(n,α)8Li(β−)8Be*(2α) Reaction for 25 and 38 MeV Neutrons
Authors: Kim C. Y.
Published: April 2011

Boron-loaded K-2 emulsions were exposed to the neutrons produced by 41 MeV protons incident upon a deuterated polyethylene target. The developed emulsions were scanned for the resulting "hammer tracks" produced from the 11B(n,α)8Li(β−)8Be*(2α) reaction. Measurements were made of the range and space angles of these events. The neutron cross section for this reaction was found to be 0.098 ± 0.057 mb for 37.7 ± 3.3 MeV neutrons and 1.87 ± 0.75 mb for 25.0 ± 3.0 MeV neutrons.
Paramagnetic Spin Susceptibility of Alkali Metals
Authors: Pant M. M. , Tong B. Y.
Published: April 2011

The paramagnetic spin susceptibility χp of alkali metals is calculated using a local pseudopotential to estimate the effect of the ions on the electron gas. The results show a trend towards better agreement with experimental results. It seems that this may be a better method of obtaining χp for simple metals, and offers a simple way to estimate χp as a function of pressure.
Antiferromagnetic Resonance in Mn2P2O7
Authors: Fowlis D. C. , Stager C. V.
Published: April 2011

Antiferromagnetic resonance has been observed in single crystal samples of Mn2P2O7. Measurements were made in narrow frequency ranges at 35 and 70 GHz over a temperature range from 1.2 to 14 °K. The results could not be fitted to the Nagamiya–Yosida theory. The results are compared with an extended theory due to Date.
Nonlinear Interactions of Waves on Shallow Water
Authors: Ionides G. N. , Curzon F. L.
Published: April 2011

This paper presents the results of theoretical and experimental investigations of second-order nonlinear interactions between standing surface waves on shallow water. The nonlinearity is introduced by the nonlinear terms in the Navier–Stokes equation and in the boundary conditions. The wave amplitudes are kept small enough for amplitude dispersion to be negligible, and the surface is treated as a resonantly driven, damped, harmonic oscillator. A pure first-order mode is excited by applying time periodic electrical stresses onto the free fluid surface, and this mode self-interacts to drive resonantly a second-order mode. The amplitudes are ultimately limited by dissipative processes in the fluid. These processes are taken into account in the theory, and the experimental results justify the assumptions made. Wave amplitudes could be monitored to a spatial resolution of 5 × 10−4 cm by an optical technique.
Debye Characteristic Temperatures of Cubic Metals
Authors: Semwal B. S. , Sharma P. K.
Published: April 2011

The validity of Hill's formulas for the shear modulus of a polycrystalline cubic solid is examined by calculating the Debye characteristic temperature at 0 °K for a number of cubic metals using the measured elastic constants. The results are compared with calorimetric values and the numbers deduced from direct numerical integration of elastic data. Various methods give nearly similar results if the anisotropy of the metallic element is not excessively large.
Equilibrium Ion Spacing and Ion-Pair Electrostatic Energy for a Finite Ionic Crystal with NaCl Structure: Point-Ion Model
Authors: Huang C. C. , Grindlay J.
Published: April 2011

The equilibrium ion spacing and energy per ion pair are calculated for a point-charge model of a slab-shaped ionic crystal with NaCl structure. The Madelung constant and the specific electrostatic surface energy are deduced. The results confirm previous work on infinite and semi-infinite models.
Electrical Properties of Sputtered MoS2 Films
Authors: Souder A. D. , Brodie D. E.
Published: April 2011

The X-ray diffraction pattern, the magnitude of the semiconductivity, and the measured electrical activation energy in r.f. sputtered films of MoS2 are found to be similar to the single crystal. The observed negative magnetoresistance is attributed to a bulk property of the films. The lack of contact noise in sputtered films simplifies the study of these materials.
A Computer Optimization of the Three Coil Magnetic Probe
Authors: Pachner Jr. J.
Published: April 2011

Results of the computer investigation of the performance of the three coil magnetic probe, described in an earlier paper by Curzon et al. are presented.
Concerning the Decay of 2.6 h 65Ni
Authors: Paradellis T. , Katsanos A. A.
Published: April 2011

The decay of 65Ni has been investigated using Ge(Li) and NaI (Tl) detectors. The results support the existence of the following states in 65Cu with corresponding spin and parity assignments: 0(3/2+), 770.7(1/2−), 1115.5(5/2−), 1481.9(7/2−), 1623.5(5/2−). and 1725.0(3/2−) keV.
A New Technique for Measuring the Velocity of Sound in Liquid Metals
Authors: Turner R. , Crozier E. D. , Cochran J. F.
Published: April 2011

Since piezoelectric transducers cease to function above 600 °C, velocity of sound measurements become difficult at high temperatures. Many of the difficulties may be circumvented by observing the acoustic waves using the electromagnetic detection technique. This method has been made the basis of an apparatus with which the sound velocity in liquid metals may be measured with an accuracy of 0.1% up to a temperature of 1300 °C. Results for liquid copper and tin are presented, to illustrate the value of the technique.
Structure of Turbulent Wakes of Hypersonic Spheres as Inferred with Ion Probes
Authors: Heckman D. , Sévigny L.
Published: April 2011

Survey arrays of ion probes have been used to study the structure of the ionized turbulent wakes of 2.7 in. diameter spheres flown at 14 500 ft/s in atmospheres of nitrogen at pressures of 7.6 and 20 Torr. For various radial distances measured from the wake axis, matrices of data points have been obtained giving random values of the axial distance behind the projectile at which ionization begins, the first ionized eddy occurs, and continuous turbulence begins. A wake radius separating the significantly ionized wake from the un-ionized wake has been obtained, and found to lie intermediate between the inviscid wake radius defined by Wilson from schlieren measurements and an electron density radius corresponding to the 1/e points of the electron density distribution defined by microwave interferometric measurements. A radius defining the extent of the ionized portion of the turbulent core has been determined; this radius is of the order of 80% of the schlieren radius of the turbulent core.The continuous turbulence data can also be used to define a wake radius; this radius has been identified as the mean position of the turbulent interface for ionized eddies, because it is in agreement with estimates of the turbulent interface obtained by fitting the radial distributions of intermittency estimates prepared from independent 0.5 ms long segments of the ion probe signals. The radius corresponding to the mean position of the turbulent interface is within the schlieren radius of the wake core. In addition to determining the mean position of the turbulent front, the standard deviation of the interface has been established. These last data have been found to be in broad agreement with data derived from measurements of the wake edge using schlieren techniques.The differences in the results obtained at 7.6 and 20 Torr have been considered and found consistent with other experimentally measured data obtained at DREV; the occurrence of a transitionary type behavior in the frequency content of the probe signals from the 7.6 Torr results has been noted but not explained.
Collisional Narrowing and the Foreign Gas Broadening of Spectral Line Shapes
Authors: Zaidi H. R.
Published: April 2011

The problem of collisional narrowing and broadening of spectral line shape in a gas is considered from the point of view of propagator technique of the many body theory. The case in which the radiator and perturbers are of different species is considered in this paper. In the impact limit, the propagator equations reduce to a form which is a generalization of the classical equations used in the previous theories. The line shapes resulting from the two approaches are compared and possible generalizations are discussed.
A Study of Thermal Neutron Capture in Aluminum
Authors: Ishaq A. F. M. , Colenbrander A. H. , Kennett T. J.
Published: April 2011

The gamma-ray spectrum following thermal neutron capture in aluminum has been studied using a Ge(Li) pair spectrometer. A total of 143 transitions has been observed above 2.1 MeV, and most of these have been placed in a decay scheme. Some 51 levels in 28Al are observed to be populated in the reaction. The Q value for the 27Al(n,γ)28Al reaction is estimated to be 7725.4 ± 0.5 keV, and the multiplicity is found to be 2.0. The mean relative strengths of primary E1 and M1 transitions have been calculated and an attempt has been made to use these to determine the multipolarities of primary transitions leading to levels of unknown parity.
A Rotational Flow for the Study of Rotations of Deformed Even–Even Nuclei
Authors: Prakash V. R. , Bahal B. M. , Deshpande V. K.
Published: April 2011

The Bohr–Mottelson hydrodynamical model is extended to include rotational flow by assuming a finite constant vorticity throughout the volume of a nucleus. The vorticity is found to vary as β2 from nucleus to nucleus, thus giving irrotational flow only for spherical nuclei with no rotational spectra.
Zero-Point Effects in Heisenberg Antiferromagnets with Arbitrary Range of Interaction
Authors: Collins M. F. , Tondon V. K.
Published: April 2011

The ground state energy, spin-wave energy, and sublattice magnetization have been calculated for a Heisenberg antiferromagnet at the absolute zero of temperature. The treatment extends the earlier work of Anderson, Kubo, and Oguchi to apply for any two-sublattice antiferromagnet with arbitrary range of interaction. It is shown that for each exchange interaction there is a different characteristic correction term to the energies. Explicit calculations are made of these terms for the simple cubic, body-centered cubic, and face-centered cubic lattices, with both first- and second-neighbor interactions. Applications are also made to NiO and MnO. An extra term in the magnetization series beyond that given by earlier workers is derived.
Rapid Numerical Solution of the One-Dimensional Schrödinger Equation
Authors: Newman William I. , Thorson Walter R.
Published: April 2011

It is shown that, contrary to common experience and opinion, the exact solutions to Schrödinger's equation in one dimension (or any similar ordinary linear second-order differential equation) can be numerically computed at a speed characterized by the variations of the potential function, i.e. at effectively the speed of solving Hamilton's equations. The method of solution depends upon the existence and calculation of certain "fundamental" and unique special solutions, closely associated with the JWKB series. These solutions have exponential form with exponents which are everywhere finite, nonoscillatory functions varying smoothly with the potential ("quantal action"); their existence does not seem to have previously been known. They are generated when a novel iterative technique is employed to solve certain Riccati equations. The expressions obtained appear to be asymptotic representations, but are numerically essentially convergent (error < 1 × 10−6) whenever the JWKB approximation is reasonably valid. Because the exponent function and its derivative ("quantal momentum") are smooth and slowly varying, this iteration can be used to generate initial values in asymptotic domains and rapid numerical integration of the Riccati equation for the quantal momentum then performed to compute the exact solutions everywhere. Because of the simple character of the solutions, a number of elegant and useful results in perfect analogy with the JWKB approximations for eigenvalue conditions (Bohr–Sommer-feid rule) and scattering phase shifts can be obtained. The method can be employed whenever the desired solution possesses more than two or three de Broglie oscillations over a region of significant variation of the potential. We have investigated the method for a number of representative potential functions; we find that it is always at least one order of magnitude faster than standard methods based on direct integration of the Schrödinger equation, and for those cases where it can be employed we believe it will render them obsolete.
Temperature Dependence of a Kohn Anomaly in Molybdenum
Authors: Buyers W. J. L. , Powell B. M. , Woods A. D. B.
Published: April 2011

Measurements of the [00ζ]L or Δ1 branch of the phonon dispersion relation for molybdenum at 88 and 298 K over the range [Formula: see text] show that the shape of the Kohn anomaly in this region is not strongly temperature dependent.
Reactions 19F(γ,xγ′) and 31P(γ,xγ′)
Authors: Thomas B. J. , Buchnea A. , Irish J. D. , McNeill K. G.
Published: April 2011

The spectra of deexcitation gamma rays following photodisintegration of 19F and 31P have been measured to study further the reaction channels involved in photodisintegration of nonclosed shell nuclei. Besides (γ,n) and (γ,p) decays to excited states of the residual nuclei, strong (γ,α) channels from 19F to the first excited state of 15N and from 31P to the first two excited states of 27Al were observed.
Generalized Fourier Transform for Stratified Media
Authors: Bahar E.
Published: April 2011

A Fourier-type transform is derived for functions satisfying the scalar wave equation in stratified media. Using this transform, the function is expressed as a sum of two infinite integrals and a discrete term. In electromagnetic theory, the infinite integrals correspond to the radiation and the lateral wave terms and the discrete term corresponds to the surface wave.The transform provides a suitable basis for the expansion of electromagnetic fields when the height of the interface between two semi-infinite media and their electromagnetic parameters vary along the propagation path. Exact boundary conditions are employed here rather than the restricted surface impedance condition. The expansion is particularly appropriate for problems in which the source and the observation point are not in the same medium.
On Doppler-Shift Attenuation Measurements
Authors: Winterbon K. B.
Published: April 2011

An improved analysis of Doppler-shifted γ spectra is outlined. This analysis is exact within the Lindhard theory of slowing down of heavy ions in solids.With an approximate cross section applicable at low energies, the equations become independent of the energy, except as a scaling parameter, and depend only on the projectile–target mass ratio. A set of universal curves of the mean fractional shift F(τ) is calculated in this approximation for several values of the mass ratio.Une analyse améliorée de spectres γ déplacés par effet Doppler est esquissée. Cette analyse est conforme à la théorie de Lindhard sur le ralentissement des ions lourds dans les solides.
The Effect of Pressure on the Electrical Conductivity of Sapphire
Authors: Piché E. , Rubin G. A.
Published: April 2011

The d.c. electrical conductivity of sapphire has been measured as a function of uniaxial pressure and temperature in the respective ranges 0 < P < 10 kbar, 300 < T < 750 °K. The activation energy for electronic conduction was found to decrease linearly with pressure yielding a zero pressure activation energy of 2.38 ± 0.02 eV. The stress coefficient α of the activation energy for electronic conduction was found to be α = 0.24 × 10−3 – 0.32 × 10−6T eV/bar.
Rotational Structure in the A2Σ+, B2Σ+, and a4Σ− – X2Π Transitions of GeF
Authors: Martin R. W. , Merer A. J.
Published: April 2011

Rotational analysis of over 50 sub-bands of three emission transitions of 74GeF has given vibrational and rotational constants for the four lowest-lying electronic states of GeF. One of these is a 4Σ− state in Hund's case (a), where all four spin components have been identified. Extensive perturbations between this 4Σ− state and the B2Σ+ state have been analyzed in detail: the two states appear to interact mainly by a second-order mechanism through the so far uncharacterized σπ22Σ+ state, but the surprisingly large J dependence of the perturbation matrix element suggests that another mechanism, possibly involving the ground state, may contribute. Further perturbations, where the lines show an unusual intensity enhancement, appear in those sub-bands with B2Σ+ ν = 4 as upper state.
Inverse Scattering from a Perfectly Conducting Prolate Spheroid in the Quasi-Static Domain
Authors: Hill D. A.
Published: April 2011

The problem of inverse scattering from a perfectly conducting prolate spheroid in the quasistatic region of a magnetic dipole source is considered. From one observation of the radial and transverse scattered magnetic fields, the parameters which identify the spheroid (interfocal distance and eccentricity) are uniquely determined. The intermediate step requires the determination of the two magnetic polarizabilities. Similar results are also obtained for the oblate spheroid by a transformation.
On the Boundary Scattering of Phonons
Authors: Srivastava G. P. , Verma G. S.
Published: April 2011

In this paper we have discussed the variational treatment of the boundary scattering of phonons. The procedure of Hamilton and Parrott for boundary scattering of phonons is modified; but still the method is shown to give Casimir's result at low temperatures.
Two-Stream Electromagnetic Instability
Authors: Seshadri S. R.
Published: April 2011

The characteristics of the instability of an electromagnetic wave propagating obliquely to a double stream in a plasma are investigated. Instability is shown to exist for all directions of the stream. The direction normal to the wave vector is a singular case for which the unstable wave has a zero frequency of oscillation and a growth rate which increases from zero as the wavenumber is increased and asymptotically approaches a maximum value for very large wavenumbers. For all other directions unstable waves exist for wavenumbers below a critical value. The frequency of oscillation increases monotonically from zero as the wavenumber is increased and reaches a maximum value at the cutoff wavenumber but the growth rate increases from zero as the wavenumber is increased, reaches a maximum value, and then decreases to zero at the critical wavenumber. The dependence of the frequency of oscillation and the growth rate of the unstable wave on the direction of the stream with respect to the wave vector is also examined. Many of the features of this instability, particularly for other than the singular direction, are predicted correctly by the quasi-static approximation.
Theory of Brueckner and Sawada Applied to a Many-Boson Model
Authors: Razavy M. , Krebes E. S.
Published: April 2011

The Bassichis–Foldy model of a simple interacting boson is solved numerically and the results are compared with those obtained by the Bogoliubov approximation and by the Brueckner–Sawada t-matrix formalism. In the normal region, contrary to the widely held view, the Brueckner–Sawada approximation for the energy of the ground state is not reliable for strong, well-behaved, repulsive forces. The Bogoliubov approximation, on the other hand, remains valid for a wide range of values of the coupling constant. In the inverted region, the attractive force causes a population inversion in the levels of the system. For this case a modified Brueckner–Sawada approximation is developed. This method is applied to the calculation of the transition point and the energies of the ground and the first excited states of the system. Here most of the predictions of the modified Brueckner–Sawada approximation are quite accurate. By a simple change in the Bassichis–Foldy model it is shown that even, for two bosons there can be a phase transition. In this model, the derivative of the ground state energy with respect to the coupling constant is discontinuous at the transition point.
Spectroscopie par Source Laser. III. Intensités et Largeurs des Raies de la Transition 00°1–10°0 du Protoxyde d'Azote. Ecarts à la Forme de Lorentz
Authors: Lacome Nelly , Boulet Christian , Arié Eric
Published: April 2011

Intensities and half-widths of self-broadened N2O have been measured in the 00°1–10°0 band by a spectroscopic method using a stabilized, single line, single mode laser source.On the other hand, line overlap has permitted us to point out a deviation from Lorentz line shape for pressures greater than atmospheric pressure. An attempt to interpret this difference by a semi-empirical formalism is proposed, proceeding from "super Lorentz" line shape recently introduced by Varanasi.
The Conformal Invariance of the Coupled Spinor–Vector Fields
Authors: Hamilton J. Dwayne
Published: April 2011

Conformal invariance of the coupled spinor–vector fields in Minkowski space is reviewed. The conservation laws corresponding to this 15-parameter Lie group are found and shown to be similar to those found by Bessel-Hagen for classical electrodynamics. Gauge invariance is maintained throughout. A brief consideration of the meaning of the conformal transformation is also given.
Sensitized Fluorescence in Sodium Induced in Collisions with Hg(63P1) Atoms
Authors: Czajkowski M. , Skardis G. , Krause L.
Published: April 2011

Collisional transfer of excitation from mercury to sodium was investigated using methods of sensitized fluorescence. A mixture of mercury and sodium vapors at low pressure was irradiated with Hg 2537 Å resonance radiation, producing a population of Hg(63P1) atoms whose inelastic collisions with ground-state sodium atoms resulted in a transfer of excitation energy to close-lying S, P, and D states in sodium. The subsequent decay of these states manifested itself in the emission of a sensitized fluorescent spectrum. Absolute intensity measurements on the components of the spectrum yielded 21 cross sections whose magnitudes range from 0.02 to 38.5 Å2 and which exhibit a pronounced resonance with ΔE, the energy defect between Hg (63P1) and the appropriate level in sodium.
The Orbital Average of the Conduction Electron g Factor
Authors: Holtham P. M.
Published: April 2011

An expression has been derived that relates the orbital average of the g factor measured in the de Haas–van Alphen effect to the local gk values computed from any theoretical model for the band structure.
Anisotropy in the Landau Fermi-Liquid Parameters for the Alkalis
Authors: Leavens C. R. , Carbotte J. P.
Published: April 2011

The electron–phonon interaction makes a significant contribution to the Landau Fermi-liquid parameters. Since the phonon spectrum in the alkalis is anisotropic, the Fermi-liquid parameters should also exhibit anisotropy. We have calculated this effect and find it particularly significant for the higher moments of the quasiparticle scattering function. In the computations, the electron–ion pseudopotential developed by Hayman and Carbotte is employed since it is known to give a good fit to the resistivity data. For comparison, some calculations were also done with the Shaw form factors. The phonons were derived from a set of Born–von Kármán force constants.