bluuebunny/crossref_metadata_2025 huggingface dataset:
THE LIFETIME OF POSITRONS ANNIHILATING IN ALUMINUM
Authors: Jones G. , Warren J. B.
Published: April 2011

The absolute lifetimes of positrons decaying in aluminum and mica have been found to be 1.7 ± 0.4 × 10−10 sec. and 2.4 ± 0.4 × 10−10 sec., in accord with the determination by B ell and Graham using a different technique.
THE LUMINOUS MANTLE OF FUEL-RICH OXYACETYLENE FLAMES: I. SPECTROSCOPIC TEMPERATURE MEASUREMENTS
Authors: Marr G. V.
Published: April 2011

The luminous mantle of fuel-rich oxyacetylene flames is a strong source of the 4050 Å bands of the C3 radical. As a preliminary to the study of the chemical kinetics involved in the formation of the electronically excited C3 radical, a temperature investigation of the luminous mantle has been undertaken. Rotational measurements are reported for the CH, C2, and OH bands over a range of burning mixtures of 2.3 to 4.2 times stoichiometric. Self-absorption is shown to occur for OH and C2 and is indicated for CH. After attempting to correct for this effect, an average rotational temperature for the three radicals of 3000 ± 200° K. decreasing to 2900 ± 200° K. is found to be applicable to the luminous mantle over the range of mixtures investigated. Vibrational temperatures obtained for CN and C2, together with predissociation studies of the CH radical, indicate that small departures from complete thermal equilibrium cannot be eliminated.
FRAUNHOFER PATTERN MEASUREMENT IN THE FRESNEL REGION
Authors: Bickmore Robert W.
Published: April 2011

A method of Fraunhofer pattern measurement is presented by which the distance between antennas may be reduced from the usual 2L2/λ to values of the order of 0.1(L2/λ). This reduction may be applied to any antenna in which the aperture plane may be physically molded about a spherical surface having a radius of curvature less than 2L2/λ. It is shown that such measurements have less inherent phase error in the region of the main lobe than the conventional measurements on a plane aperture at 2L2/λ.
GENETIC MEASUREMENT OF THE HALF LIFE OF Bi207
Authors: Bell R. E. , Sosniak J.
Published: April 2011

The half life of Bi207 has been measured by the genetic method, using the parent–daughter pair Po207 and Bi207. Both activities are electron capturers, and the measured half life depends only on the activity ratio between them. The value found, T½ = 28±3 years, agrees with one of three previous determinations of this half life.
A STUDY OF μ-MESONS INCIDENT AT LARGE ZENITH ANGLES
Authors: Wilson B. G.
Published: April 2011

A Geiger counter telescope has been employed to study μ-mesons incident at large zenith angles. The counters were hodoscoped in pairs enabling the direction and angle of incidence of the particles to be determined. The intensity has been analyzed as a function of arrival time but no significant variation has been found either in solar time or sidereal time. However, a variation in solar time has been noted on analysis of extensive air showers measured concurrently. The angular variation of intensity has been studied and absolute rates obtained; these rates have been compared with those of an earlier determination showing excellent agreement. Some evidence has been obtained of a directional anisotropy in the μ-meson flux as measured at the apparatus.
SOME PROPERTIES OF THE 2.23-MEV EXCITED STATE OF P31
Authors: Litherland A. E. , Bartholomew G. A. , Gove H. E. , Paul E. B.
Published: April 2011

The 2.23-Mev excited state of P31 has been studied by means of the capture gamma rays from the 1.70-Mev resonance in the reaction Si30(pγ)P31. The angular correlation of the ground state gamma ray established that the resonance had total angular momentum 3/2, and triple correlation measurements of the cascading gamma rays from the compound state showed that the angular momentum of the 2.23-Mev state was 5/2. Coincidence measurements showed that the cascade gamma rays from the 2.23-Mev state to the first excited state at 11.27-Mev were [Formula: see text] of the transitions to the ground state.
ABSORPTION SPECTRUM OF THE NO MOLECULE: II. NEW FINE-STRUCTURE ANALYSES BELOW 1600 Å
Authors: Lagerqvist A. , Miescher E.
Published: April 2011

Several new excited doublet states of the nitric oxide molecule are identified. Some of these are upper states of NO bands observed in the visible and infrared.
Sensitized fluorescence in vapors of alkali metals. X. Energy transfer in sodium–sodium collisions
Authors: Pitre John , Krause L.
Published: April 2011

The total cross sections for 3 2P1/2–3 2P3/2 mixing collisions between excited and unexcited sodium atoms have been determined in a series of sensitized fluorescence experiments with pure sodium vapor at pressures in the range 0–1.6 × 10−5 mm Hg. The cross section Q2(3 2P1/2 ← 3 2P3/2) was found to be 283 Å2 ± 10%. The cross section Q1(3 2P1/2 → 3 2P3/2) = 532 Å2 was obtained from Q2 through the application of the principle of detailed balancing.
Optical energy gap variation in GaxIn1−x As alloys
Authors: Woolley John C. , Thomas Mathew B. , Thompson Alan G.
Published: April 2011

Room-temperature optical energy-gap values have been determined for GaxIn1−x As alloys, and have been corrected, where necessary, for the Burstein effect by finding Fermi energy values from thermoelectric power data. The results show good agreement with the empirical equations given previously for mixed III–V alloys.
The nuclear magnetic moment of indium-117m
Authors: Mufti A. R. , Cameron J. A. , Waddington J. C. , Summers-Gill R. G.
Published: April 2011

The hyperfine structure of 1.9-hour 117mIn has been investigated using atomic magnetic resonance. In the 2P1/2 and 2P3/2 electronic states, the magnetic dipole interaction constants are[Formula: see text]If the possibility of a hyperfine anomaly is neglected, the nuclear magnetic moment of 117mIn is −0.251 46 ± 0.000 03 nuclear magnetons. Thus the nucleus follows the trend shown by other 2p1/2 proton nuclei, namely that the addition of a neutron pair always reduces the deviation from the Schmidt value.
Blast waves from a laser-induced spark in air
Authors: Panarella E. , Savic P.
Published: April 2011

The explanation of the peculiar shape and motion of the laser-induced air spark given by Ramsden and Savic (1964) implies that at the end of the laser pulse heated air fills a spherical sector bounded by the focused laser beam. This air volume expands and forms a blast wave with perturbed spherical symmetry. In this paper, the motion of this wave is considered theoretically and the results are compared with recent interferometric measurements by Alcock, Panarella, and Ramsden (1965).
Polarization of electron-impact light from helium
Authors: Whitteker J. H. , Dalby F. W.
Published: April 2011

The polarization of electron-impact light from helium has been measured for the multiplets 2 3P–2 3S (10 829 Å) and 3 3P–2 3S (3889 Å) for electron energies in the range from threshold to 50 eV. For the 2 3P–2 3S multiplet, the observed polarization rises to 21% near threshold and by means of a curve fitting procedure may be extrapolated to (32 ± 6)% at threshold. For the 3 3P–2 3S multiplet, the observed polarization rises to 11% and may be extrapolated to (15 + 3)%.
Intensity measurements in emission of 18 Vegard–Kaplan bands of N2
Authors: Chandraiah G. , Shepherd G. G.
Published: April 2011

The Vegard–Kaplan band system of nitrogen was excited by running a low-current discharge through a pure xenon–nitrogen mixture contained in a 6-liter spherical bulb of a discharge tube. Photoelectric measurements of the relative intensities of 18 bands (λ 2340–4324 Å) have been made using a 1-m Ebert–Fastie spectrometer. These measured band intensities were used along with Franck–Condon factors qν′ν″ and r centroids [Formula: see text] to study the variation of the electronic transition moment Re(r) with internuclear separation r. It was found that over the measured range from r = 1.23 to 1.43 Å that Re(r) could be represented by[Formula: see text]A "smoothed" set of band strengths [Formula: see text] was determined from this expression for all the observed bands of the Vegard–Kaplan system.
Rejection of observations and censorship
Authors: Williamson J. H.
Published: April 2011

It often happens that a set of experimental data contains some readings which look wrong. In order to avoid the awkward choice as to whether or not these observations should be rejected, it is recommended that all samples of N readings be censored by ignoring the m largest and m smallest readings and the mean be taken of the remaining n readings. The optimum values of n are tabulated. For a Cauchy distribution, the median is the best statistic only for very small samples.
Electron spin resonance of Mn2+ in Cd2V2O7
Authors: Stager Carl V.
Published: April 2011

The electron spin resonance of Mn2+ impurities has been investigated in single crystals of Cd2V2O7. The spin-Hamiltonian parameters are gx = 2.0004(8), gy = 1.9995(8), gz = 2.0001(8), b20 = −419(1)g, b22 = 125(2)g, Ax = −86.7(3)g, Ay = −87.0(10)g, and Az = −87.4(5)g. The results have been compared with similar studies on isomorphic crystals and with a calculation employing the point-charge model for the crystal field. The model gives reasonable agreement with the experimental results.
Origin of photoconductivity oscillations in CdS and CuCl
Authors: Haering R. R. , Batra I. P.
Published: April 2011

An oscillatory dependence of photoconductivity on photon energy has been observed in many semiconductors. In some semiconductors the amplitude of the oscillations depends strongly on the magnitude of the applied electric field, while in others it is independent of the electric field. Field-dependent oscillations have been successfully accounted for in the literature but no adequate explanation has been offered so far for the second type of oscillations. We propose that these oscillations are the result of variations in the optical absorption coefficient arising from exciton formation by second- or higher-order processes involving longitudinal optical phonons as well as the incident radiation.
The correction of cosmic-ray energy spectra for instrumental noise
Authors: Judge R. J. R. , Nash W. F.
Published: April 2011

A mathematical method is described for the correction of energy spectra of cosmic-ray particles for the effects of scattering by spectrometer material and for errors in trajectory determination. The advantage of applying such corrections lies in the more accurate construction of incident spectra and hence better comparison with theoretical models.
Some new transitions in the L emission spectrum of erbium-68
Authors: Deodhar G. B. , Singh R. B. , Varma P. P.
Published: April 2011

A systematic study of the L spectrum of erbium with a 40-cm curved mica crystal spectrograph showed the existence of two new dipole transitions, LIIOI(γ8) λ1343.50 x.u. and LIIINIV(β15) λ1512.74 x.u., and three new forbidden transitions, L1OI λ1276.81 x.u., LIOIV, v λ1268.68 x.u., and LIIOII, III λ1339.81 x.u. The transitions LIIOIV(γ6) and LIIIOIV, V(β5) reported earlier only by Sakellaridis have been confirmed. However, the transition LIMV(β9) reported only by Coster remained unconfirmed.
CO adsorption on (100) and (211) tungsten single-crystal surfaces: Changes in work function
Authors: Armstrong R. A.
Published: April 2011

The adsorption of CO on two large single crystals of tungsten exposing (100) and (211) surfaces has been studied by measuring changes in the work function [Formula: see text] at 300 °K and above, where some CO remained adsorbed. The results for the two surfaces were quite different.CO adsorbed on the clean W(100) surface at room temperature as β-CO causing [Formula: see text] to increase by 0.48 V. As β adsorption saturated, α-CO adsorption began and caused [Formula: see text] to decrease. The major effect of heating was desorption.CO adsorbed on the clean W(211) surface with a sticking probability near unity and increased [Formula: see text] by 0.68 V. Heating the crystal to temperatures below 1100 °K produced large irreversible changes in [Formula: see text]. These irreversible changes are attributed to the formation and dissociation on the surface of complexes consisting of two CO molecules.
On the Green function theory of a Heisenberg antiferromagnet
Authors: Dembinski S. T.
Published: April 2011

Some of the consequences of a recently proposed first-order decoupling are examined in the Green function theory of a [Formula: see text] Heisenberg antiferromagnet. The low-temperature magnetization differs in terms proportional to T4 from Oguchi's spin wave formula. The Neél temperature is equal to the R.P.A, Curie temperature.
Admittance of an annular slot in a magnetoplasma
Authors: Seshadri S. R.
Published: April 2011

The admittance of an annular slot situated on a perfectly conducting, infinite plane screen covered with an unbounded, uniform magnetoplasma is investigated for the case when an external static magnetic field is perpendicular to the plane of the screen. The slot is assumed to be driven by a coaxial line which in turn is excited in its dominant TEM mode, and the field in the slot is approximated by that incident on it. A generalized plane wave representation for the fields is developed using Bessel transforms, and integral expressions are derived for the admittance of the slot. Extensive numerical results and a detailed discussion of the dependence of the admittance on the strength of the static magnetic field, the complete range of operating frequencies, and the radius and the width of the slot are also included.
Laser-induced breakdown in freon-doped rare gas
Authors: Young M. , Chin S. L. , Isenor N. R.
Published: April 2011

The breakdown of argon gas containing freon-12 impurity is reported. At high pressure the freon increases the breakdown threshold, while at low pressure it decreases the threshold. This behavior is shown to result from attachment and multiphoton ionization of the freon. The experiment is considered to provide further evidence for multiphoton ionization and for the cascade theory of breakdown.
The influence of ambipolar diffusion on the shape of radio echoes from meteors
Authors: Šimek M.
Published: April 2011

Meteor velocities can be determined from the diffraction characteristics of radar echoes from under-dense trails, but may be in error if atmospheric diffusion is neglected. Error factors are presented for circumstances when the diffusion coefficient is known. By a suitable selection of measurements beginning with the first minimum, the error in velocity may be held to about 1%.
Observation and interpretation of the airglow emissions
Authors: Gattinger R. L.
Published: April 2011

The [Formula: see text] band at a wavelength of 1.58 μ has been observed with a scanning Fabry–Perot system in the evening twilight airglow at 45.2 °N. The decay time constant at a solar depression angle of 10° was about 45 minutes during the winter and about 30 minutes during the summer. The brightness at a solar depression angle of 6° was about 25 kR for both seasons. The emission could not be detected in the morning twilight. Theoretical solutions were obtained for an oxygen–hydrogen atmosphere to explain the observed behavior of the emission, with the assumption that excitation of the O2(1Δg) state is mainly due to photodissociation of ozone in the Hartley continuum. The results indicate that the ozone dissociation mechanism is probably the correct one. Formation of the O2(1Δg) state by three-body recombination of atomic oxygen has also been included to explain the observed emission of the [Formula: see text] 0,0 band at a wavelength of 1.27 μ in the night airglow. The evening twilight seasonal brightness variations of the 1.27 μ and 1.58 μ bands observed with ground-based instruments have not been satisfactorily explained.
Rotational line intensities in 3Σ–1Σ electronic transitions
Authors: Watson James K. G.
Published: April 2011

Formulae are given for the intensities of rotational lines in 3Σ–1Σ electronic transitions of linear molecules, allowing for the effects of spin–spin interaction. For [Formula: see text] transitions an error in the relative phases of the two transition moments in the work of Schlapp (1932) is corrected. Recent observations on SO and HCP support this change in phases.
Etude des intensités et des largeurs des raies de vibration–rotation de la bande deuxième harmonique de l'anhydride carbonique à 6970 cm−1 par déconvolution numérique
Authors: Arcas Philippe , Hochard-Demolliere Lucette
Published: April 2011

The intensity and half-width of the 12CO2 3ν3 band lines are determined, the instrumental effects being corrected by numerical calculations. The square of the vibrational moment (R03)2 is found to be equal to 0.233 × 10−42 e.s.u. With a quadrupolar momentum Q = 5.2 × 10−26 e.s.u., the line-width variation curve versus J can be approximately interpreted by Anderson's theory.
On a certain dynamical invariance in quantum field theory
Authors: Razavy M.
Published: April 2011

The invariance of the equation of motion of classical fields under a certain type of transformation which is inversely proportional to the coupling constant is studied. A model of a nonlinear self-interacting boson field with this kind of invariance is constructed and then quantized. The vertex function in the lowest order of the N-quantum approximation is obtained, and it is shown that without a cutoff this invariance is not preserved. As a second example, a special form of the scale transformation is applied to the equations of motion of an electron interacting with the electromagnetic field. It is shown that the vacuum state of the transformed electromagnetic field is different from the original vacuum state and that these vacuum states are orthogonal to each other. For this problem, the perturbative technique for the solution of the quantized fields leads to the breakdown of the invariance.
The magnetic interaction effect. I. Interaction of two frequencies
Authors: Shoenberg D.
Published: April 2011

The magnetic interaction of two periodic terms in the de Haas – van Alphen effect is examined for both weak and strong interaction [Formula: see text]. It is found that the amplitudes of the combination frequencies (and, in particular, the difference frequency) generated by interaction in the parallel component of M are always very weak, if the amplitude of one of the periodic terms is dominant and the frequency of the subsidiary term is close to an integral multiple of the dominant frequency. For the perpendicular component of M, however, in the limit of strong interaction, the amplitude of the difference frequency of two nearly equal frequencies can be relatively much stronger than for the parallel component, if the anisotropy of the Fermi surface is such that the two frequencies vary appreciably differently with orientation. These results are discussed in terms of their relevance to various experimental situations, in particular to the observation by Joseph and Thorsen (1965) of a strong difference frequency in the perpendicular component of M, arising from the nearly equal central and noncentral belly frequencies in silver.
Stability of gravitating fluid layer of infinite extent but finite thickness including Hall effect
Authors: Das K. P.
Published: April 2011

The stability of a gravitating, homogeneous, incompressible fluid layer of infinite extent but finite thickness is considered, including Hall effect, by the use of the normal mode method. A uniform magnetic field is assumed to be present throughout parallel to its boundary. The displacement current is neglected. An asymptotic analysis for small nonzero Hall current shows a destabilizing effect of order ε where ε is the perturbation parameter. The stability analysis is restricted to plane-symmetric modes.
Rotational analysis of the blue–green system of scandium oxide
Authors: Adams Annabel , Klemperer W. , Dunn T. M.
Published: April 2011

The blue–green emission system of scandium oxide has been reanalyzed as 2Σ → 2Σ instead of 2Σ → 4Σ, as was previously suggested. The fine doubling seen in the spectrum (~0.25 cm−1) is attributed to nuclear hyperfine effects, the ground state being essentially a bβS coupling case and the excited state, bβJ. The hyperfine splitting in the upper 2Σ level is very small and has not been observed directly, whereas the ground-state interaction is large, indicating that the ground term arises from an essentially 4sσ configuration. The ground-state splitting alone is responsible for the observable hyperfine structure features of the spectrum.The transition in the orange–red is, accordingly, assigned as 2Π → 2Σ, the splitting once again being confined to the ground term. The details of this system will be dealt with in a separate paper.
Far-infrared absorption of alkali halide crystals containing H− ions
Authors: Woll Jr. E. J. , Gethins T. , Timusk T.
Published: April 2011

The optical absorption from localized vibrations associated with the H− ion as a substitutional impurity in KBr and KI is investigated in the far infrared. A force constant model for the defect is derived from a theoretical fit of the experimental results for the anharmonic side band of the H− local mode. This model is used to predict the absorption spectrum of the defect in the far infrared below the Reststrahlen frequency. Good agreement is obtained with absorption measurements at low temperature. It is shown that some of the observed peaks correspond to localized modes, while others are directly related to van Hove singularities in the frequency spectrum of the host crystal.
Attitude determination of rocket-released probes from polarization measurements
Authors: Kavadas A. , Campbell D. S.
Published: April 2011

A method for determining the instantaneous orientation of rocket-released probes is described. The technique involves an analysis of the telemetry signal that is received on two orthogonally oriented linear antennas and a circularly polarized antenna.The signal, which is intensity modulated by the rotational or tumbling motion of the probe, is shown to have periodic maxima. The relative time displacements between maxima at the three polarizations are shown to contain all the information necessary for the determination of the probe orientation. The probe attitude may be completely and unambiguously defined if the telemetry signals are received at two widely separated sites.This method may be used successfully for the attitude determination of any rotating probe or vehicle equipped with a transmitting antenna whose radiation pattern has a detectable maximum. If the vehicle carries a magnetometer or any other direction sensor, its attitude may be completely specified without the aid of the second telemetry receiving site.
Z1 oscillations in stopping of atomic particles
Authors: Winterbon K. B.
Published: April 2011

The measured stopping cross sections for atomic projectiles in various materials show Z1 oscillations, a more or less periodic dependence of the stopping on Z1, the atomic number of the projectile.These oscillations have a larger amplitude when the projectiles are channeled in single crystals than when they are not.In this paper it is shown that the oscillations are a size effect, i.e., the larger an atom the more it is ionized and the greater is the stopping. Calculation of stopping of low [Formula: see text] channeled particles in tungsten and silicon give qualitative agreement with experiment: the maxima and minima are in the right places, and vary in the right way, but the calculated amplitude of oscillation is too small. Possible explanations for the amplitude discrepancy are suggested.
The Hall effect and Kelvin–Helmholtz instability in a plasma
Authors: Sen Amiya K. , Chou Chih Kang
Published: April 2011

It is shown that a new unstable mode due to the Hall effect appears in the Kelvin–Helmholtz problem in an ideal plasma. The instability appears whether or not the Kelvin–Helmholtz discontinuity is stable or unstable in the absence of a Hall current. An upper bound on the growth rate of the Hall instability is found to be of the order of the ion cyclotron frequency.
Core-excitation model for 127I
Authors: Castel B.
Published: April 2011

The nuclear properties of low-lying levels of 127I are discussed in terms of a core-excitation model. The core and particle parameters are determined by a simultaneous fitting of the available experimental data into a least-square program. Compared with the predictions of Kisslinger and Sorensen, the calculated results are seen to yield better agreement with the measured E2 transition rates.
On the apparent mass distributions of underdense radio meteors
Authors: Jones J.
Published: April 2011

A method of obtaining the mass distribution index of meteoroids from the amplitude distribution index of underdense radio meteor echoes which takes into account the effects of the initial train radius and the finite velocity has been developed.Application of this method to existing data has enabled a new value for the initial radius of meteor trains to be obtained which is in good agreement with other determinations.
Critical angles for channeling of low energy ions in tungsten
Authors: Bergström I. , Björkqvist K. , Domeij B. , Fladda G. , Andersen S.
Published: April 2011

The critical angle ψ for channeling of light and heavy ions in crystals has been studied around the [Formula: see text] direction in a tungsten single crystal by measuring the yield of backscattered ions at room temperature. The ions and their energies E were chosen such that the critical angle was comparable to, or larger than, the ratio between the screening radius a and the atom spacing along the string d. According to Lindhard [Formula: see text] for ψ < a/d and [Formula: see text]. We have studied the variation of the critical angle with E/Z1 for the ions 1H, 2H, 4He, 12C, 20Ne, 40Ar, and 84Kr in the critical angle region 4a/d > ψ > a/d. For 12C, 20Ne, 40Ar, and 84Kr, most of our data is in the transition region between ψ1 and ψ2, but an approach to the ψ2 behavior can be seen at the low energy end. For 1H, 2H, and 4He, however, the energy dependence is rather of the ψ1-type for the whole region studied, that is even for critical angles as large as ψ = 4a/d. The value of the multiplicative constant C2 is also different for the two cases, being close to 1 for the heavy ions but about 2 or larger for the light ions.
Turbulence functions useful for probes (space–time correlation) and for scattering (wave-number–frequency spectrum) analysis
Authors: Shkarofsky I. P.
Published: April 2011

The wave-number–frequency dependent spectral function, S(k, ω), and the space–time correlation function, C(r, t), are considered in a turbulent flowing plasma. The decay mechanisms are associated with either velocity fluctuations about the mean convection velocity or diffusion effects or attachment, or combinations of these, including the Brownian motion model. The ψ(k, ω) function, which is the ratio of S(k, ω) to its frequency-integrated value, depends on the mechanism and exhibits a profile which can be Gaussian, Lorentzian, a Z function, a Hermite polynomial modification of the Gaussian, or a confluent hypergeometric function. Anisotropic forms are also considered.The function C(r, t), obtained by convolving ψ (r, t) with C(r), the space autocorrelation function, is next considered. Adopting a Gaussian or an exponential model (which may be anisotropic) for C(r), we illustrate C(r, t) forms, which can readily be manipulated. Furthermore, letting r = 0, we derive two conditions for the applicability of Taylor's hypothesis. The assumption of frozen flow is not necessary, only that the root-mean-square Lagrangian displacement in a given time, associated with the decay, be much smaller than both the flow distance and the characteristic size of blobs having maximum energy.
Dislocation relaxation in tantalum at low temperatures
Authors: Verdini L. , Vienneau L. A.
Published: April 2011

A maximum in the dissipation vs. temperature curve has been observed at about 25 °K in tantalum after a permanent deformation of about 7%. The temperature of the maximum increases with the vibration frequency indicating the presence of a thermally activated relaxation process. This effect is attributed to the dislocation motion (Bordoni peak) and the characteristic parameters are W = 0.038 eV and [Formula: see text]. Using the Seeger equation, a value for the Peierls' stress of about 6.5 × 106 dyn cm−2 is found. The presence of a large spectrum of relaxation times is also discussed.
Higher order corrections to the rigid rotator law I(I + 1)
Authors: Gupta Raj K.
Published: April 2011

A two-parameter model is developed for the rotational states in deformed even–even nuclei by assuming that the nuclear moment of inertia is modified due to centrifugal stretching, and the resulting change in shape (i.e. the β-vibrations) is balanced by harmonic restoring forces. The rotational energy expression is obtained in the form of an asymptotic series which enabled us to investigate the conditions for the eventual breakdown of (macroscopic) rotational structure at high angular momentum and also to distinguish between 'soft' rotator and hard rotator.
Velocity dispersion in Brillouin scattering
Authors: Bhatia A. B. , Tong E.
Published: April 2011

The dispersion relations for the velocity v for temporally absorbed hypersonic waves and for the velocity vB as determined from the positions of the Doppler-shifted Brillouin peaks are discussed for a single relaxation process. The difference between v and vB is significant whenever the sound absorption per cycle is not much smaller than unity.
Lattice dynamics of III–V compounds
Authors: Banerjee R. , Varshni Y. P.
Published: April 2011

The lattice dynamics of III–V compounds has been investigated on a 'rigid ion' type of model. The interactions are assumed to consist of Coulomb forces with an effective charge and a general force constant field up to and including second neighbors. Results are presented for the dispersion curves, frequency distribution functions, and effective calorimetric and X-ray Debye temperatures for AlSb, GaP, GaAs, and InSb. The agreement with the experimental data, where available, is reasonable.
On the origin of defect states in calcium tungstate
Authors: Sayer M. , Souder A. D.
Published: April 2011

A comparison has been made of thermoluminescence and thermally stimulated current in single crystals of calcium tungstate either doped with impurities or nominally pure but excited by ionizing radiation. Both effects were large in the case of monovalent impurities with glow peaks near 260 °K being characteristic of the impurity and peaks near 160 °K arising from an enhancement of a structure which normally results from radiation damage. Trivalent impurities had a lesser effect with the production of glow peaks near 300 °K. The structures responsible for the prominent glow peaks are suggested to be: 260 °K—monovalent ions in calcium sites, 154/160 °K—oxygen vacancies associated with either a W5+ or a monovalent ion at a calcium site, 300 °K—calcium vacancies. The occupancy of electron and hole traps is found to be related. This relationship is used to deduce information regarding the excitation mechanism for free holes and electrons in calcium tungstate.
An isotope effect on 62P1/2–62P3/2 mixing in cesium, induced in collisions with CH4 and CD4
Authors: McGillis D. A. , Krause L.
Published: April 2011

62P1/2 ↔ 62P3/2 excitation transfer in cesium, induced in collisions with CH4 and CD4 molecules, has been studied in relation to the temperature of the vapour–gas mixtures. The variation with temperature of the cross section ratio Q(CH4)/Q(CD4) is ascribed to an isotope effect which is interpreted on the basis of the theory of absolute reaction rates.
Studies of the CO2+ [A2Πu → X2Πg] bands using photon excitation from the neutral molecule
Authors: Judge D. L. , Bloom G. S. , Morse A. L.
Published: April 2011

Extreme ultraviolet photons of known energy have been used to form CO2+ in specific states of excitation. This technique provides a greatly simplified emission spectrum compared with any other means of excitation. Thus, a number of bands previously observed in high-resolution studies have now been properly identified owing to the simplicity of the present spectra. In addition, the symmetric stretching quantum v1 and the bending quantum v2, for the CO2+X2Πg state have been determined. The value of v1 is only slightly different from that found by Mrozowski. The bending quantum v2 has not been previously reported and is [Formula: see text].
Lifetime of the 29.4 keV level in 40K
Authors: Boulter J. F. , Prestwich W. V. , Arad B.
Published: April 2011

The half-life of the first excited state of 40K at 29.4 keV, populated by the 39K(n,γ)40K reaction, has been measured using two scintillation detectors. The result obtained was T1/2 = 4.26 ±.08 ns. A procedure for calibrating a time-to-amplitude converter using commercial electronic modules is described.
Perturbation treatment of the Hartree–Fock equations for the ground states of the boron-like ions
Authors: Sharma C. S. , Wilson R. G.
Published: April 2011

The first-order Hartree–Fock and unrestricted Hartree–Fock equations for the ground state of a five electron atomic system are solved exactly. The solutions are used to evaluate the corresponding second-order energies exactly and the third-order energies with great accuracy. The first-order terms in the expectation values of 1/r, r, r2, and δ(r) are also calculated.
Green's function approach to the Ising model
Authors: Lee K. C. , Barrie Robert
Published: April 2011

It is shown that the spin [Formula: see text] Ising model can be formulated as a spinless fermion many-body problem and that the Green's function technique can be applied to it. The hierarchy of Green's function equations of motion terminates at the (q + 1)-particle Green's function, where q is the coordination number. This finite number of equations yields Fisher's transformation of correlations. The technique discussed in this paper can be used to obtain exact results for the one-dimensional Ising model.
Scalar hydrodynamics and gravitation
Authors: O'Hanlon John , Tam Kwok-Kee
Published: April 2011

The relativistic hydrodynamical equations governing the behavior of a system of classical particles interacting through a scalar field in the presence of gravitation are presented. The motion of a scalarly charged particle in external scalar and gravitational fields is investigated. The linear dispersion relation for a zero-temperature, classical scalar plasma in the presence of an external gravitational field is also derived. Some consequences are discussed.
Energy levels of excited in the decay of the 94Tcm,g isomeric pair
Authors: Barrette J. , Boutard A. , Monaro S.
Published: April 2011

The γ-ray spectra resulting from the decay of the 94Tcm,g isomeric pair to the excited states of 94Mo have been investigated using Ge(Li) solid state detectors. Gamma rays (relative intensities are in parentheses) of 871.05(100); 993.19(2.35); 1196.4(0.80); 1522.1 (4.80); 1868.68(6.10); 2393.2(0.50); 2529.8(0.33); 2740.1(3.74); 3129.1(1.47); 3512.5(0.06); 3793.1(0.05); 3892.7(0.016); plus several other weak lines have been observed in the decay of 94Tcm(52 min). Gamma rays (relative intensities are in parentheses) of 449.2(3.3); 532.1(2.35); 702.67(99.7); 742.3(1.21); 849.74(95.8); 871.05(100); 961.10(7.6); 1509.3(0.68); 1592.1(2.25); 1765.6(0.29) have been detected in the decay of 94Tcg(5 h). To investigate this latter activity a hollow coaxial Ge(Li) spectrometer was also used as a well-type detector in order to obtain sum spectra of coincident gamma rays. The overall results obtained from this study allows construction of a level scheme of 94Mo which compares fairly well with previous investigations and removes some inconsistencies shown in Coulomb excitation measurements.
Relation between nuclear level density parameters and mass shell corrections
Authors: Brancazio P. J. , Cameron A. G. W.
Published: April 2011

Previous work by Gilbert and Cameron has demonstrated a linear relation between the nuclear level density parameter a and the mass shell correction S. However, different relations were obtained for deformed and undeformed nuclei. We show that a single relation can be obtained if a deformation energy is added to the reference mass formula. This deformation energy is shown to be proportional to the number of neutrons or protons to the nearest closed shell.
Phonon renormalization of the electronic effective mass
Authors: Carbotte J. P. , Dynes R. C. , Trofimenkoff P. N.
Published: April 2011

We have made detailed first principle calculations of the phonon contribution to the renormalization of the electronic effective mass of a number of simple metals and alloys. The phonon frequencies and polarization vectors are generated from the interatomic force constants for the material. The force constants are taken from a Born – von Kármán analysis of the experimental phonon dispersion curves determined by inelastic neutron scattering. The electron–phonon interaction is treated using pseudo-potential theory which relates the coupling constant to the electron–ion form factor. For a spherical Fermi surface it is then possible to evaluate numerically the expression for the effective mass with no further approximations. We compare the results obtained with previous work when available and with experiment otherwise.
A physical model of a radio aurora event
Authors: McDiarmid D. R. , McNamara A. G.
Published: April 2011

A physical model is proposed to relate and explain the data obtained during a radio aurora event which occurred during the International Geophysical Year. One of Boström's electrojet models and the Farley two-stream instability form the basis of this model. The echoes obtained during the event were found to originate in the plasma bands associated with the visual forms and the orientation of the electric field was found to be east–west, which is in agreement with that predicted by the magnetospheric convection model of Brice.
Muons in large extensive air showers
Authors: Earnshaw J. C. , Orford K. J. , Turver K. E.
Published: April 2011

An error in the data on the muon component of extensive air showers presented at the 10th International Conference on Cosmic Rays is corrected. The effect on the explanation of the anomalies in the muon data which involved an abnormally large transverse momentum is considered, and an alternative explanation for the persisting anomalies in the data is suggested.
Calculations of the equilibrium configurations of flux lines in thin films of type II superconductors
Authors: Carter C.
Published: April 2011

The London theory is used to calculate the equilibrium configurations of flux lines in thin films of a type II superconductor as a function of the applied magnetic field. Three possible geometrical configurations, of increasing complexity, are considered in detail, and the Gibbs function is minimized with respect to the parameters which define the configuration. The range of applied magnetic field for which each configuration is stable is determined, and hence B–H curves are constructed. A transition from one configuration to another causes a discontinuity in the B–H curve at values of H which roughly correspond to those found experimentally by Sutton.
Lower bounds to eigenvalues
Authors: Cohen Maurice , Feldmann Tova
Published: April 2011

The classical procedure of Weinstein has been employed to obtain rigorous upper and lower bounds to the eigenvalues E of a quantum mechanical Hamiltonian operator H. The new bounds represent an improvement over Weinstein's bounds for any reasonable choice of variational trial function. In the case of the lowest eigenvalue E0, for which the Rayleigh–Ritz procedure gives the optimum upper bound, the new lower bound is an improvement over the lower bound formula of Stevenson and Crawford.
Admittance of a solid cylindrical antenna
Authors: Lee S. W. , Mittra R.
Published: April 2011

The problem of calculating the current and admittance of a solid cylindrical antenna is of great practical interest. Yet, unlike the hollow tubular antenna, the above subject has found little attention in the literature. In the present paper, the solution to this problem is constructed in two steps. The first of these involves the derivation of an expression for the reflection coefficient at the end of a semi-infinite solid cylinder, which is obtained by solving a modified Wiener–Hopf equation using a newly-developed technique. Convenient expressions for the current and admittance of the antenna are derived next by considering multiple-reflection phenomena at the ends of the antenna. These expressions are further simplified for thin antennas, i.e. for [Formula: see text], and it is shown that the effect of the end caps, as reflected in the admittance of such an antenna, is to increase its effective length by approximately 0.26a.
Absorption by gaseous and solid HD and solid para-H2 in the far infrared
Authors: Trefler M. , Cappel A. M. , Gush H. P.
Published: April 2011

The absorption spectrum of HD at 300 °K, 77.3 °K, and 4.2 °K (solid) has been measured in the frequency range of 40 to 450 cm−1. The spectrum is the sum of a collision-induced part associated with ΔJ = 2 rotational–translational transitions, and an allowed electric-dipole part associated with ΔJ = 1 rotational transitions. The intensity of the induced part of the spectrum has been compared with theoretical predictions; a significant discrepancy between the measured and calculated intensity of the S(0) line in the solid is noted. The intensity of the corresponding feature in solid parahydrogen has also been measured and a similar discrepancy exists.
Rocket measurements of O2(1Δg)
Authors: Haslett J. C. , Megill L. R. , Schiff H. I.
Published: April 2011

Four rockets have been flown at Fort Churchill, Manitoba, to study the O2 (1Δg) concentration. Each rocket carried a single two-channel photometer sensitive to 1.27 μ radiation from the (1Δg → 3Σg−) (0,0) transition of O2. Information on the diurnal variation of both the total intensity and the height profile was obtained. The results agree with those reported by other observers and show the expected decay of the profile with increasing zenith angle. Some balloon-flight data are reported also.
Luminescence from evaporated films of CdS
Authors: Conradi J.
Published: April 2011

Luminescence spectra from evaporated films of CdS are obtained under pulsed electron beam excitation. The transitions giving rise to the luminescence are identified as resulting from the recombination of bound electrons with bound holes and the simultaneous emission of n LO phonons (n = 0, 1, 2, … ), and the recombination of free electrons with bound holes. The addition of a 2000 Å thick coating of SiOx on top of the CdS is shown to produce a degenerate surface concentration of electrons which shifts the peak position of the free–bound transition to higher energies.
Close-packed anisotropic antiferromagnetic Ising lattices. I
Authors: Stephenson John
Published: April 2011

A detailed account of the nonmagnetic thermodynamic properties of the two-dimensional, anisotropic, antiferromagnetic, triangular Ising lattice, in the absence of a magnetic field, is presented. The notion of a disorder temperature, TD, is introduced via the exact integral formula for the logarithm of the partition function per spin, and the energy and entropy per spin are evaluated explicitly at TD. Study of the theoretical specific heat curves, and of graphs of the percentage of energy and entropy below the Néel point, shows that the close-packed antiferromagnetic triangular lattice has a qualitatively different behavior from two-dimensional loose-packed lattices. It is suggested that a similar situation will occur in three-dimensional close-packed lattices, and therefore that it is important to use a close-packed Ising model for comparison with experimental data on antiferromagnets which have close-packed lattice structure, or loose-packed lattice structure with higher neighbor interactions.
A modified Born approximation for singular potentials
Authors: Eu Byung Chan
Published: April 2011

The variable-phase method is used to obtain nondiverging Born phase shifts for a singular (Lennard–Jones (12,6)) potential. An exemplary calculation is made for the parameters kσ = 18 and εσ2 = 125, and the agreement between the approximate and exact differential scattering cross sections is fairly good.
Effect of the lattice vibrations on the rotational excitations in solid hydrogen
Authors: Noolandi J. , Kranendonk J. Van
Published: April 2011

The theory of the interaction between the lattice vibrations and the rotational excitations in solid H2 is developed using the self-consistent harmonic phonon model with short-range correlations. First- and second-order perturbations in the roton energy levels are calculated using the expansion of the roton–phonon interaction in terms of the quantum-crystal phonon operators derived in a previous paper. The first-order reduction of the quadrupolar coupling constant due to the difference of the longitudinal and transverse sound velocities is calculated and compared with the effect of the short-range correlations. Second-order shifts due to the modulation of the crystalline field and the quadrupolar interactions by the lattice vibrations are also calculated using an isotropic model for the rotons. The roton self-energy shifts are expressed in terms of an effective quadrupolar coupling constant and the dependence of this constant on the roton wave vector is studied. The coupling constant is shown to be appreciably different for propagating and localized rotational excitations.
Level structure of 88Rb
Authors: Lycklama H. , Kennett T. J.
Published: April 2011

The beta decay of 2.8 h 88Kr has been investigated using a high-resolution and good efficiency 40 cm3 coaxial Ge(Li) counter. A total of 40 gamma rays were detected and determined to belong to the beta decay of 88Kr. All but one of these were placed in a consistent decay scheme. As a result it was possible to give a plausible interpretation to the level structure of 88Rb.
Coincidence measurements of the first excited state of 73Ge
Authors: Douglas D. G.
Published: April 2011

A coincidence measurement of the K conversion coefficient of the 13.26 keV transition from the first excited state of 73Ge yields a result closer to the E2 theoretical value than that of an earlier less-precise measurement.The half-life of the level is found to be 2.95 ± 0.05 s in agreement with one of two disagreeing previous values.
Intermediate-coupling structure of odd-A nuclei in the 2s–1d shell
Authors: Castel B. , Stewart K. W. C. , Harvey M.
Published: April 2011

The positive parity energy spectra of 29Si, 31P, and 35Cl are calculated in terms of a modified intermediate-coupling model. The vibrating cores are assumed to be 28Si, 32S, and 36Ar respectively, with the 1d3/2, 2s1/2, and 1d5/2 orbits available to particle and hole states. Account is taken of the anharmonicity of the two-phonon core states. The calculated energy spectra and decay schemes are in agreement with recent experimental results with parameter values consistent with previous studies in the s–d shell.
Density and velocity fields in collisionless flow past a diffusely reflecting cone
Authors: Elliott James Parker
Published: April 2011

Results of flow field calculations for the collisionless flow of a neutral, monatomic gas past a diffusely reflecting right circular cone at zero angle of attack with the free stream are presented. Singularities at the vertex and at the shoulder of the base are illustrated and discussed. Comparison is made with similar results for spheres and two-dimensional polygonal bodies and with results for transition flow past sharp cones. Methods for improving the analysis are suggested.
Two one-dimensional Ising models with disorder points
Authors: Stephenson John
Published: April 2011

Pair correlations on two one-dimensional Ising models with next-nearest-neighbor interactions are calculated exactly. For an appropriate range of values of the interaction energies, each of these models exhibits a disorder point, at which the nature of the short-range order changes abruptly, and at which there is a cusp in the graph of range of order vs. temperature. The zero-field susceptibilities are calculated exactly, and are found to have quite smooth temperature dependence.