bluuebunny/crossref_metadata_2025 huggingface dataset:
Dipole matrix elements for vibration–rotation lines in the fundamental band of the hydrogen bromide molecule
Authors: Gustafson Bruce P. , Rao B. Sesh
Published: April 2011

The equivalent widths of 16 lines in the fundamental vibration–rotation band of the H79Br molecule are measured in the linear region of the curve-of-growth method. The measurements are made on a Littrow type high-resolution infrared grating spectrometer in a double-pass manner so that the two isotopic lines of H79Br and H81Br, which are separated by approximately 0.4 cm−1, could be completely resolved. From the measurements of equivalent widths, the strengths and squares of the dipole matrix elements for the spectral lines are calculated. This is the first time the high-resolution work on the fundamental band has ever been presented. The present high-resolution values are found to be approximately one-half of the values of an earlier low-resolution work.
On the morphology of auroral absorption during substorms
Authors: Jelly Doris H.
Published: April 2011

Multistation riometer measurements of ionospheric radio-wave absorption have been used to infer the characteristics of the higher-energy component of electron precipitation during substorms. Two analyses are presented which deal separately with longitudinal and latitudinal variations. The first is based on data from four riometer stations located at L ≈ 5.2 and at about 90° longitude intervals, and the second on a chain of five riometer stations spaced at about 3° intervals across the auroral zone. Previous work has shown that substorms detected at night are accompanied by daytime precipitation. In the present study, the average substorm absorption is found to have two broad maxima, one at night within 15 min of the absorption onset, and another during the morning about an hour after this onset. There is very little effect in the evening.From the latitude study, a transition is observed during the nighttime phase of substorms between the abrupt, irregular, intense absorption at higher latitudes and the smoother, less intense absorption at lower latitudes. This transition, designated as Λa, is observed at a median latitude of Λa = 65 ± 1.5°. For the majority of a sample of 181 events selected from 1964 and 1967 records, the absorption was observed to start in the vicinity of Λa. With increased magnetic disturbance (measured by Kp), Λa is observed to shift to lower latitudes. The Kp variation is compared with that of energetic-particle boundaries.
Absorption of hydromagnetic waves in the ionosphere
Authors: Abbas M.
Published: April 2011

Absorption of hydromagnetic waves in the ionosphere propagated normal to the magnetic field is calculated at various frequencies and compared with the absorption for parallel propagation. Data corresponding to both daytime and nighttime ionospheres are used. Waves propagated normal to the magnetic field are highly absorbed through the daytime ionosphere at frequencies above a few Hz; the nighttime ionosphere, however, is virtually transparent to waves in the frequency range of 10−3 to 20 Hz. A comparison of the absorption processes for waves propagated parallel and normal to the magnetic field is made.
Transmission of the infrared oxygen emission at 1.27 μ in the atmosphere
Authors: Evans W. F. J. , Wood H. C. , Llewellyn E. J.
Published: April 2011

The transmission of the (0–0) band of the infrared atmospheric system of oxygen through the atmosphere has been calculated using an analytic approximation to the Voigt line profile. The zenith transmission at the ground, for an emission temperature of 200 °K, is calculated to be 6.5% in agreement with the value determined from ground-based observations of the twilight airglow at 1.27 μ. These calculations also indicate that the atmospheric transmission is dependent on the emission temperature which may vary with season and time of day.
A fast "τx" spin–lattice relaxation process in phosphorus donor pairs in silicon
Authors: Marko J. R.
Published: April 2011

A mechanism is proposed to explain the observed fast τx spin–lattice relaxation processes observed in close phosphorus donor pairs in silicon. The mechanism is based on a mixing of states of different total electronic spin by the hyperfine interaction and a modulation of the pair exchange energy by the lattice vibrations. The exchange-energy expression used is calculated from single-atom wave functions composed of linear combinations of the Bloch states at the six conduction-band minima. The resultant relaxation rate is shown to agree with experimental observations.
Summer daytime height profiles of O2(1Δ) concentration at Fort Churchill
Authors: Wood H. C. , Evans W. F. J. , Llewellyn E. J. , Jones A. Vallance
Published: April 2011

The height distribution of O2(1Δ) molecules was measured during the daytime by means of filter photometers flown to 95 km on Black Brant III rockets. The height distributions obtained show main peaks at 55 km (afternoon, solar elevation 18.2°) and at 59 km (morning, solar elevation 9.2°). The concentrations above 80 km show significant enhancements over those predicted from ozone photolysis on the basis of the ozone concentrations predicted by most previous theoretical models.
Radiation from a magnetic line source in a moving isotropic plasma
Authors: Kojima T. , Itakura K.
Published: April 2011

The problem of radiation from an electric dipole placed in a moving isotropic plasma has been studied by Lee and Papas for a special case where the velocity of the plasma is relatively small compared with the light velocity in vacuum. In this paper, we consider a radiation problem for a more general case where no restriction is imposed on the magnitude of the velocity of the plasma, and for a case where the source of radiation is assumed to be a magnetic line source.We investigate theoretically the effects of the movement of the plasma on the far-zone radiated electromagnetic fields and on the radiation pattern. The results show that the Poynting vector has a circumferential component, and therefore the direction of radiated-energy flow deviates from the radial direction, and it depends on the magnitude of the velocity of the plasma and on the angle between the position vector of an observer and the velocity vector of the plasma. Some numerical examples of its deviation and of the radiation pattern are illustrated.
Lifetime of the 6s6p1P1 level of barium
Authors: Dickie L. O. , Kelly F. M.
Published: April 2011

The lifetime of the first excited singlet P level of barium, 6s6p1P1, has been determined from the width of the zero field level crossing, i.e. the Hanle effect, of the 6s6p1P1 –6s21S0, 5535 Å resonance line. The resonance radiation was produced in a hollow cathode lamp and the scattering atoms by an atomic beam. After taking account of coherence narrowing, the lifetime is determined to be 8.37 ± 0.14 × 10−9 s, in good agreement with other recent work.
Photoneutrino energy loss rates
Authors: Chaudhuri Probhas Ray
Published: April 2011

The neutrino energy loss rate due to the photoneutrino process in a hot plasma, including the contributions from positrons in the black body radiation according to the photon–neutrino coupling theory, has been obtained. This is then compared with that obtained on the basis of the current–current coupling theory of weak interactions for a variety of conditions.
Theory of excitation transfer in collisions between alkali atoms. II. Dissimilar partners
Authors: Dashevskaya E. I. , Nikitin E. E. , Voronin A. I. , Zembekov A. A.
Published: April 2011

Possible mechanisms are considered for the transfer of electronic excitation energy in collisions between an excited alkali atom MA*(2Pj) and an unexcited atom MB(2S1/2). It is shown that a dipole–dipole interaction which is responsible for the transfer of electronic excitation energy in collisions between identical partners (MA = MB) is not sufficient to explain the observed magnitudes of the cross sections and that, therefore, the exchange interaction can no longer be neglected. If the exchange interaction is taken into account, it can be shown that there are regions of nonadiabaticity in the energy diagram, which are probably responsible for the change in the electronic energy states of the collision partners. The calculated cross sections are compared with experimental values.
De Haas – van Alphen effect and Fermi surface of the intermetallic compound PtSn
Authors: Cathey W. N. , Coleridge P. T. , Jan J.-P.
Published: April 2011

Extremal cross sections of the Fermi surface of the intermetallic compound PtSn (NiAs structure) have been determined by means of the de Haas – van Alphen effect. The Fermi surface proposed here is similar to that found in isostructural AuSn by Edwards et al. Several of the frequencies have been inverted to yield the profile of the corresponding sheets of the Fermi surface. An approximate determination of the dimensions of the other sheets shows that the observed Fermi surface encloses 4.60 ± 0.27 electrons per formula unit; this suggests that one or several sheets of the Fermi surface containing 0.6 d-band holes per platinum atom have remained undetected. Some cyclotron masses have been measured and to explain all the features of the experimental results, it is necessary to invoke spin splitting with a g factor different from 2, and to postulate magnetic breakdown.
Low-temperature electrical resistivity and magnetic susceptibility of dilute Mg–Ce alloys
Authors: Hedgcock F. T. , Petrie B.
Published: April 2011

The electrical resistivity of a series of magnesium alloys containing from 300 to 1041 parts per million of gadolinium has been measured from 4.2 °K to room temperature. No low-temperature anomalies have been observed and it is found that Matthiessen's rule is obeyed extremely well over the whole temperature range studied. The electrical resistivity and magnetic susceptibility measurements indicate that the cerium ion in magnesium is in a triply ionized state, and that the contribution to the resistivity can be almost totally accounted for by assuming normal potential impurity scattering. This suggests that the f level of cerium in magnesium lies well below the fermi level of magnesium and that there is very little s–f mixing between the f level of cerium of the conduction electron states of magnesium.
Hyperfine effects in radiative muon capture
Authors: Guardiola R. , Pascual P.
Published: April 2011

In this paper a general theory of partial radiative muon capture is presented, including the hyperfine effects. Use is made of the impulse approximation, neglecting the nucleon velocity-dependent terms.
Direct experimental evidence of multiphoton ionization of impurities as the initiation process of laser-induced gas breakdown
Authors: Chin S. L.
Published: April 2011

Using a focused Q-switched ruby laser, multiphoton ionization of the background gas of an ordinary vacuum system was observed by the time-of-flight method and an electron multiplier. The number of free electrons created at the focal region was found to be at least more than 20. Since a few free electrons would be sufficient for the initiation of the laser-induced spark in gases (Young and Hercher), it was thus concluded that multiphoton ionization of gas impurities is the initiation mechanism of the optical breakdown of gases, as is generally believed.
On the Knight shift in cadmium and cadmium–mercury alloys
Authors: Williams D. Llewelyn , Sharma S. N.
Published: April 2011

Additional Knight shift measurements on cadmium are presented which eliminate the possibility of an anomaly in the neighborhood of 150 °K. Results on a Cd88Hg12 single crystal are interpreted in terms of the smearing of the periodicity of the pseudopotential as a result of alloying.
Temperature decay of a laser-produced aluminum plasma
Authors: Burnett N. H. , Smy P. R.
Published: April 2011

The temperature of the plasma produced by Q-spoiled laser irradiation of an aluminum target has been measured by monitoring the emission and absorption through a small cross section of the plasma in the early stages of the flare decay. The temperature obtained in this manner is found to be much less than previous estimates based on the velocities of emitted ions, but is in good agreement with recent measurements on a carbon plasma.
K X-ray gamma-ray directional correlation in the decay of 114Inm with a sum-peak-coincidence scintillation spectrometer
Authors: Murty D. S. , Rao K. V. Ramana , Jagam P. , Lakshminarayana V.
Published: April 2011

The evidence obtained for the existence of the K X-ray gamma-ray directional correlation by Perepelkin against the predictions of the theory of Dolginov evoked considerable interest in this field. The electron capture decay of 114Inm is used to advantage in the present investigation with a sum-peak-coincidence scintillation spectrometer. The results obtained are consistent with the theory of Dolginov.
Slow motion of a sphere in a two-phase medium
Authors: Michael D. H. , Norey P. W.
Published: April 2011

An analysis is given for the slow motion of a sphere in a viscous fluid with a solid particle suspension. It is assumed that the relaxation time of the suspended particles is small enough for a perturbation analysis to be performed on the steady Stokes solution for the flow past the sphere. The analysis is similar to that given by Michael for the motion of a sphere in a dusty gas, at large Reynolds number, but the physical conditions under which this flow may be realized are very different. If it is assumed that "dusty gas" conditions apply, in which the density of the solid suspension is much greater than that of the gas, the effect of gravity on the motion of particles will be small compared with the Stokes resistance only when [Formula: see text], where a is the sphere radius, v the kinematic viscosity of the gas, and g the gravitational acceleration. For air this condition limits the sphere size to 10−2 cm. In this context the conditions therefore apply to small length scale effects in which a particle moves through a suspension of much smaller particles.Perhaps a more interesting situation arises when the two phases have comparable densities, and in particular when the particles are neutrally buoyant in a very viscous liquid, when gravity effects do not enter the problem, and the sphere size need not be so restricted. Our analysis assumes, following Saffman, that the bulk concentration of particles is small enough to be neglected, and it would follow in this case that the mass concentration is small enough to leave the liquid flow unaffected. However, the formal analysis given here is not restricted to this case.The final section of this paper is concerned with a related problem of finding the critical value of the Stokes number σ for which a particle will collide with the sphere, for Stokes flow. This number was previously given as σ = 1.214 by Langmuir, using a step-by-step integration. Our method gives σ = 1.21194, correct to five decimal places. This calculation, however, does not take account of the buildup of resistance as a particle approaches the sphere, and the number must be regarded as the value of σ at which a particle will approach to within a distance of the order of its diameter to the sphere, in a finite time.
Elastic scattering phenomena in mass analyzers with tandem fields
Authors: Ioanoviciu D.
Published: April 2011

The elastic scattering in the tandem field mass analyzing systems is considered. The analysis includes deflecting electrostatic and magnetic converging, dispersing, diverging fields, and also the fields of quadrupoles. The influence of slits located on the ion beam path is indicated. An example illustrates the effect of slits on the elastically scattered current distribution in a double focusing mass spectrometer. Another example gives an idea about the influence of the diverging field on the peak tails in mass spectra.
Axial and radial temperature profiles in a weakly ionized argon jet
Authors: Morgan F. J. , Nicholls R. W.
Published: April 2011

Diagnostic studies were made on a supersonic (Mach 2.5) weakly ionized plasma jet in argon. Electrical probe techniques were used in conjunction with spectroscopic and photographic methods. The results indicate a fairly uniform axial behavior of temperature, but the radial profiles show considerable variation. Temperature measurements made by different methods disagree sufficiently to show a probable lack of equilibrium between translational, rotational, vibrational, and electronic excitation energy modes.
Photoconductivity in some III–V alloys
Authors: Taylor A. E. , Fortin E.
Published: April 2011

Photoconducting properties of GaAs–InAs and GaAs–GaSb alloys were investigated at room and low temperatures. The peaks in the photoresponse were found to vary smoothly across the alloy systems. Band gap values obtained from the spectral sensitivity curves confirmed the parabolic variation of energy gaps as a function of the alloy concentration, as previously found in electrical conductivity and optical absorption measurements. The room temperature detectivity of the samples was between 2 × 105 and 8 × 106 cm (Hz)1/2 W−1 for wavelengths varying from 0.8 to 3.5 μ, depending on alloy composition.
Plasma sheath around a floating cylindrical antenna at high power
Authors: Rubinstein J. , Laframboise J. G.
Published: April 2011

At high frequencies the time-averaged effect of the radiation field near an antenna is to add the term a2E2(r) to the Coulomb potential. Its inclusion in a self-consistent Poisson–Vlasov analysis shows that a high power antenna may acquire a strong positive floating potential.Electron, ion, and potential profiles are obtained from numerical calculations and the effect on antenna impedance is discussed. Time taken to acquire positive potentials is estimated.
Two-band model in flux flow of type-II superconductors
Authors: Ho Lai-Chak
Published: April 2011

A two-band model for the flux-flow resistivity and the Hall angle of type-II superconductors in low magnetic field regions is studied using the Bardeen–Stephen theory. The original theory considers free electrons only in the normal cores of the vortices. Results are obtained which qualitatively explain some experimental data.
Vibrational distribution of populations and kinetics of the CO–N2 system in the fundamental and harmonic regions
Authors: Legay-Sommaire N. , Legay F.
Published: April 2011

The vibroluminescence of carbon monoxide excited by activated nitrogen is investigated under high resolution in the fundamental and harmonic regions. The rotational population, corrected in some cases for self-absorption, shows a Boltzmann distribution characterized by a rotational temperature of 400 °K, but the vibrational population definitely shows a non-Boltzmann distribution which coincides very accurately with a Treanor-type distribution. This distribution is due, as explained by the theory of Treanor, to the anharmonicity of the molecules and to the inefficiency of the vibration–translation transfer. The variation of the number of vibrational quanta as a function of time allows a determination of the vibration–vibration rate transfer and shows the intervention of a deactivation process interpreted as due to CN radicals. Results in the harmonic region give ratios of the square of matrix elements which are compared with theoretical values and with other experimental values.
Excitations in a Bose gas at finite temperatures. I. Shielded potential in the Hartree approximation
Authors: Cheung T. H. , Griffin Allan
Published: April 2011

Making use of the finite-temperature version of Beliaev's field-theoretical description of an interacting Bose gas, we sum the self-energy diagrams which correspond to the collisionless shielded potential approximation (SPA). This generalizes Bogoliubov's first-order results by replacing the bare repulsive interaction by a dynamically shielded interaction and includes the effect of the excited atoms. This theory is completely equivalent to that of Tserkovnikov if we use the ideal Bose gas approximation for the polarization function which screens the two-particle interaction. The excitation spectrum is found to have a single resonance. We do not find any convincing evidence for the additional high frequency second sound mode obtained by Tserkovnikov.
Une deuxième bande de conduction dans Cd3As2
Authors: Aubin M. , Brizard R. , Messa J. P.
Published: April 2011

Magneto-Seebeck and magnetoresistance measurements were performed on polycrystalline samples of Cd3As2 at 80 °K and at 300 °K. The result gives an effective mass of m*(0) = 0.012m at the bottom of the first conduction band thereby agreeing with Blom and Schrama's determination. Heavily doped samples reveal the presence of a second conduction band whose minimum is 0.40 eV above the first minimum.
Anomalous 96Zr resonance integral to thermal activation cross-section ratio and the neutron activation resonance integral of 94Zr and 96Zr
Authors: Ricabarra M. D. , Turjanski R. , Ricabarra G. H.
Published: April 2011

Values of the reduced activity resonance integral relative to the thermal cross section, I′/σ0, of 96Zr and 94Zr were determined relative to gold by measuring cadmium ratios in a reactor spectrum.Due to the anomalous characteristics of 96Zr a measurement of I′/σ0 for 96Zr was undertaken in a "quasi" thermal spectrum.96Zr and 94Zr activation resonance integrals were also determined by measuring the ratio of effective activation cross section of zirconium to 55Mn. International Atomic Energy Agency (IAEA) calibrated gamma sources were used to determine the samples' absolute activities. A lithium-drifted germanium γ-ray spectrometer was used in all cases to resolve the activities of the irradiated samples.The results for 96Zr are I′/σ0 = 879 ± 96, I′ = 4.97 ± 0.50 b, and σ0 = 5.7 ± 10 mb; for 94Zr I′/σ0 = 5.87 ± 0.05, I′ = 0.369 ± 0.037 b, and derived σ0 = 63 ± 8 mb.I′/σ0 for 96Zr is an order of magnitude or more greater than that found for stable isotopes. This suggests that almost 100% of the activation resonance integral of 96Zr consists of p-neutron captures. This fact is not consistent with the present knowledge of p-strength functions in the 90 < A < 130 mass region.
High-temperature properties of the Ising model on the octahedral lattice
Authors: Oitmaa J. , Elliott C. J.
Published: April 2011

The high-temperature initial susceptibility and specific heat of the spin 1/2 Ising model on the octahedral lattice are investigated by the method of exact series expansions. From the susceptibility series the critical temperature is found to be νc = tanh J/kTc = 0.1613 ± 0.0001. By using a method due to Gibberd the specific-heat series is calculated to 15 terms but a reliable estimate of the exponent a is not obtained, although the results do support the presently believed value α = 1/8.
Emission spectrum of the PO molecule. I. A new B′2Πi–X2Πr transition
Authors: Verma R. D.
Published: April 2011

A new system of the PO molecule in the region 4800–3800 Å has been obtained. Rotational analysis of its seven bands establishes the transition involved to be B′2Πi–X2Πr, where X2Πr is the known ground state of the molecule. The molecular constants of the lower and upper levels have been evaluated.
Second-order Raman spectrum of ZnSe
Authors: Irwin J. C. , LaCombe J.
Published: April 2011

The first- and second-order Raman spectra of ZnSe have been measured and an interpretation of the spectra has been carried out. The first-order spectrum yielded the values [Formula: see text] and [Formula: see text] for the longitudinal and transverse optical phonons at the center of the Brillouin zone. The zone boundary frequencies at the critical points X, L, and W have been estimated from the second-order spectrum. These frequencies were chosen to be consistent with both the experimental results and a theoretical model. The resulting values were further checked for consistency with a sum rule and by using regularities observed previously in the phonon spectra of zinc blende semiconductors.
152Eug and 226Ra relative γ-ray intensities for rapid efficiency calibrations of Ge(Li) detectors
Authors: Mowatt R. S.
Published: April 2011

The relative intensities of γ rays following the decay of 152Eug and 226Ra (in equilibrium with its decay products) have been studied in order to obtain rapid efficiency calibrations of Ge(Li) detectors.
Application of truncated multipolar expansion pair functions in atomic structure calculations
Authors: Jankowski K.
Published: April 2011

A class of truncated multipolar expansion pair functions (TMEPF) for the application in atomic structure calculations is defined and their properties as well as their relationships to pair functions which were applied previously are discussed briefly. In order to get a better insight into the effectiveness of TMEPF's in representing the properties essential for correlated pair functions a pilot calculation of the energy and expectation values of some operators for the ground state of H−, He, and Li+ is also presented.
Impurity shift in the NMR of iron
Authors: Wertheim G. K.
Published: April 2011

It is shown that the recently reported differences between the 57Fe NMR frequencies in natural and isotopically enriched iron can be entirely accounted for by chemical impurities known to be present in the enriched sample. The suggestion that the observed differences arise from an isotope shift therefore loses much of its force.
Entrapment of helium ions at (100) and (110) tungsten surfaces
Authors: Kornelsen E. V.
Published: April 2011

Two (100) and two (110) tungsten surfaces have been bombarded with helium ions of selected energies between 5 and 2000 eV. The helium thermal desorption spectra obtained when the targets were subsequently heated at 40 °K/s were used to deduce the fraction of the incident particles trapped in the crystal, and their binding energies. For ion energies ≤400 eV, the fractions trapped were small (~ 1 × 10−3 on the (100) surfaces and ~ 1 × 10−2 on the (110) surfaces) and almost all the trapping occurred in surface-related sites with binding energies ≤ 2.1 eV. For ion energies >500 eV, trapping occurred predominantly in sites characteristic of the bulk material, the sites being created by the incoming ions as soon as their energy was sufficient to produce atomic displacements in the lattice (480 eV). At doses <1 × 1013 ions/cm2, four characteristic binding energies were observed: 2.65, 3.05, 3.35, and 4.15 eV. At higher doses, additional binding states were observed with energies up to 5.4 eV.The results suggest that helium diffuses rapidly in tungsten at room temperature and that it is trapped within the crystals only if it encounters lattice defects. Estimates of the ion penetration depth lead to the tentative conclusion that in the annealed crystals (ion energies < 400 eV) the fractional trap concentration is <1 × 10−9 and the helium incident at a few hundred eV energy becomes trapped at depths up to at least 1 μ.
Zero field splitting of Ni2+ in lanthanum magnesium double nitrate
Authors: Kao D. , Walsh D.
Published: April 2011

Evidence is presented which indicates that for Ni2+ in lanthanum magnesium double nitrate the zero field splitting of the ground state has not been adequately accounted for. Better agreement between theory and experiment is obtained by allowing a partial breakdown of Russell–Saunders coupling. The deduced deviation from the Landé interval rule depends significantly on the covalency contribution to the zero field splitting.
On the Landau–Lifshitz relaxation in ferromagnetic metals
Authors: Kamberský V.
Published: April 2011

Scattering of ferromagnetic band-electrons by phonons combined with the spin–orbit interaction is shown to cause magnetic relaxation of the Landau–Lifshitz–Gilbert type. Two formally distinct processes are simply analyzed: (a) spin-flip scattering of electrons and (b) ordinary scattering between spin-dependent band levels. Estimates of the magnitude of the damping constant λ are derived for both cases, which agree in orders of magnitude with the experimental values for Fe and Ni. Relations of direct and inverse proportionality between λ and the ordinary collision frequency are found in the cases (a) and (b), respectively.
Note on the anisotropy of the correlation function for impurity angular momentum and the conduction electrons spins in alloys with cerium impurities
Authors: Nagi A. D. Singh
Published: April 2011

Using a diagrammatic method and employing the exchange interaction Hamiltonian given by Coqblin and Schrieffer, the correlation function for the impurity angular momentum and the conduction electrons spins for alloys with cerium impurities is computed up to second order in J. The correlation function shows a strong anisotropic behavior.
Positron annihilation in methane gas
Authors: Smith P. M. , Paul D. A. L.
Published: April 2011

The annihilation of positrons in methane gas at room temperature has been measured at pressures below 2 atm. The annihilation rate for the free positron component is proportional to the gas density and corresponds to an effective number of electrons per molecule taking part in annihilation, Zeff = 139.6 ± 1.0 (standard error). The quenching of orthopositronium corresponds to 1Zeff = 0.57 ± 0.07. Resonance annihilation is discussed in a general way.
Semidiurnal Anisotropy of Galactic Cosmic Ray Intensity
Authors: Subramanian G.
Published: April 2011

The semidiurnal variation of galactic cosmic ray intensity is investigated using data from mainly high counting rate neutron and meson monitors during 1964–1968. It is shown that in order to explain the observed semidiurnal variation it is necessary that an anisotropy of cosmic ray intensity be present in interplanetary space. The energy spectrum and the asymptotic latitude dependence of the anisotropy are then determined. The energy spectrum has a positive exponent close to + 1 for the power law in energy. The strength of the anisotropy decreases more rapidly than cosλ with increasing asymptotic latitude λ, both cos2λ and cos3λ being acceptable. The distribution of cosmic ray intensity in the range of heliolatitudes ± 7.25° at the orbit of the earth, obtained using data from the Ottawa neutron monitor, does not support the explanation of the semidiurnal variation based on the models of Subramanian and Sarabhai or Lietti and Quenby.
Decay Study of 76Br
Authors: Ladenbauer-Bellis I. M. , Bakhru H. , Bakhru Rani
Published: April 2011

The decay of bromine-76 was studied using high resolution Ge(Li) detectors in singles and coincidence mode. Bromine-76 was produced via various reactions, i.e., 75As(α, 3n), 76Br and 65Cu(14N, 3n), 76Kr(14.8 h decay to 76Br). The results of these experiments verified the previously reported levels of 76Se, studied by (d,d′) reaction. In addition to the previously described transitions, the following levels in 76Se were observed: 1689.5, 1942, 2890, 2949, 3600, 3910, 4030, 4140, 4570 keV. Accurate energies for the various γ rays were obtained using several Ge(Li) detectors in conjunction with a PDP-8/I computer. The mass difference between 76Br/76Se was measured to be 4680 ± 100 keV. A comparison of the level schemes of the even–even, neutron deficient Se isotope is given.
New Electronic Transition of the Propargyl Radical
Authors: Dubois I. , Leclercq H.
Published: April 2011

A new system of diffuse bands in the spectral region 2000–3000 Å has been found after a flash discharge in allene, propylene, or acetylene. Those bands are assigned to a new transition of the propargyl radical CH2—C≡CH.
An Action-at-a-Distance Theory of Gravitation
Authors: Volkov A. B.
Published: April 2011

An action-at-a-distance theory is formulated as a possible alternative to the general theory of relativity. The observed gravitational frequency shift and light bending are obtained by photon energy and momentum conservation effects and gravitational–electromagnetic phenomena are interpreted in analogy with the quantum theory of dielectric dispersion. The observed perihelion advance of Mercury is obtained by a combined scalar and vector interaction theory of the Wheeler–Feynman type. The vector interaction is no longer excluded by conventional field theoretic arguments.
A Note on the D′2Πr State of the PO Molecule
Authors: Verma R. D.
Published: April 2011

Observed vibrational levels of the D′2Πr state of the PO molecule at 48 835.4 and 48 854.4 cm−1 corresponding to P16O and P18O are shown to have vibrational numbering ν and ν + 1 respectively, where ν is shown to be large (≈21). From this, T0 of D′2Πr is predicted to be about 38 000 cm−1
Energies of Some 25Al Levels from the 24Mg(p,γ)25Al Reaction and the Coulomb-Energy Differences of Analog Rotational Bands
Authors: Everling F. , Morgan G. L. , Miller D. W. , Seagondollar L. W. , Tillman Jr. P. W.
Published: April 2011

Gamma rays from the 24Mg(p, γ)25Al reaction at the 1201 and 1485 keV resonances were measured with a 20 cm3 Ge(Li) detector. Excitation energies obtained for known levels in 25Al are (in keV): 1612.5 ± 0.5, 1789.6 ± 1.3, 3424.3 ± 0.6, and 3696.3 ± 1.1. By using the known 1201.4 ± 1.0 keV resonance energy, a more precise Q value of 2271.4 ± 1.2 keV is obtained, 16 keV lower than the previous value which had a 6 keV uncertainty.A brief discussion of the Coulomb-energy differences of 25Al and 25Mg analog rotational bands in relation to the 24Mg ground-state band is given and compared with the situation at mass number A = 21.
Electron Concentration and Mobility in Semimetallic CdO
Authors: Koffyberg F. P.
Published: April 2011

Measurements of the Hall constant and mobility in the temperature range 81–1100 °K were carried out on n-type CdO single crystals with defect concentrations of 1.9–31.7 × 1018/cm3. Carrier concentrations were found to be independent of temperature, indicating complete ionization of the defect donors and semimetallic conduction. At high temperature the mobility appears to be limited by optical phonon scattering, while at low temperature ionized defect scattering is the dominant process. The apparent increase of the effective mass at low temperatures from 0.15 m0 to 0.45 m0 with increasing defect concentrations is ascribed to increasing nonparabolicity of the conduction band resulting from the addition of donor states to the band.
Study of the Decay of the 3.696 MeV Level in 25Al
Authors: McCallum G. J. , Sparks R. J. , Coote G. E. , Pohl K. P.
Published: April 2011

The decay of the 3.696 MeV level in 25Al has been studied by means of the 24Mg(p,γ)25Al reaction at the 1.49 MeV resonance. Gamma-ray branching ratios, direct angular distributions, and lifetimes determined by the Doppler shift attenuation method are reported.
An Experiment to Compress Polarized 3He Gas
Authors: Timsit R. S. , Daniels J. M. , Dennig E. I. , Kiang A. K. C. , May A. D.
Published: April 2011

Helium-3, polarized by optical pumping of the 23S1 metastable atoms at 1 Torr pressure, has been compressed to a pressure of 217 Torr and it has been verified that the gas remains polarized. 3He at 1 Torr was polarized and compressed into a storage bulb using a Toepler pump, and this was repeated with successive charges of 3He until the pressure in the storage bulb rose to 217 Torr after about 4 h of operation. Some of the gas was returned to the low pressure side of the equipment and its polarization was measured. The polarization attained before each charge was compressed was 0.04; the measured polarization of the returned gas was 0.03.
Raman Effect in Cuprous Oxide Compared with Infrared Absorption
Authors: Taylor J. C. W. , Weichman F. L.
Published: April 2011

A complex Raman spectrum of Cu2O has been measured using the Kr laser line at 6471 Å, and comparison with the infrared absorption spectrum is made. An F2g Raman active phonon, postulated from symmetry considerations and infrared absorption measurements to lie at either 606 or 181 cm−1, could not be observed. Strong lines are, however, observed at 220, 204, and 192 cm−1.
Spectrum of Trebly Ionized Bromine
Authors: Joshi Y. N. , Budhiraja C. J.
Published: April 2011

The spectrum of Br IV has been completely revised and extended on the basis of new data in the region 2420 Å – 310 Å. Out of 136 lines classified, 104 are new lines. The new value of the ionization potential of Br IV has been found to be 363 395 cm−1.
Independent Yields of Mass-135 Xenons in the Thermal Neutron Fission of 233U, 235U,239Pu, and 241Pu
Authors: Hawkings R. C. , Edwards W. J. , Olmstead W. J.
Published: April 2011

The ratio of the independent yield of 135Xe to the cumulative chain yield of 135I in thermal neutron fission of 233U, 235U, 239Pu, and 241Pu has been measured using radiochemical techniques. 135Xe and 135Xem were recovered quantitatively after short irradiations and compared with 135Xe grown from 135I in the same sample. Corrections were applied for interference from other fission-product gases in the NaI(Tl) γ-ray spectrometry of the rare gas fractions. If the independent yield for 135Xem is assumed to be zero, the ratio of the independent yield of 135Xe to the cumulative chain yield to 135I is found to be 0.2790 ± 0.0069 for 233U, 0.0357 ± 0.0019 for 235U, 0.1782 ± 0.0023 for 239Pu, and 0.0332 ± 0.0016 for 241Pu.The ratio of the cumulative chain yield to 135I for thermal fission of 239Pu to that for 241Pu was found to be 0.966 ± 0.054.
Microwave Surface Impedance Measurements of a Dielectric Wedge on a Perfect Conductor
Authors: King R. J. , Hustig C. H.
Published: April 2011

The surface impedance for grazing incidence over a 1° dielectric wedge on a perfect conductor was investigated experimentally at 4.75 GHz. The results were compared with simple two-layer parallel stratified theory, and the geometrical-optics theory given by Schlak and Wait for propagation over a wedge region composed of two media. The experiment was designed to investigate the limitations of these theories.The directive nature of the surface impedance is discussed, and it is concluded that the difference in the surface impedance for the two directions of propagation can be attributed entirely to scattering. If the surface is well suited to support a surface wave and scattering is not the dominant feature, simple parallel two-layer theory seems to best describe the surface impedance. On the other hand, if the surface supports a surface wave poorly and there is significant scattering, geometrical-optics theory works best.A recent full wave solution given by Bahar was used to explain some of the limitations of the geometrical-optics theory, and the conclusions drawn from the experimental data concur with his analysis.
Noise Spectrum Measurements from 10 Hz to 1 MHz Using a Tunable Switching Radiometer. II. Application to EPR
Authors: Buckmaster H. A. , Rathie R. S.
Published: April 2011

The 1/f noise spectra and conversion gain of 10 GHz point-contact, Schottky barrier and backward microwave diodes are compared with the object of determining the relative merit of their application in electron paramagnetic resonance (EPR) spectrometers. These measurements were made absolutely using the tunable switching radiometer described by BRI and relatively by determining the EPR microwave sample cavity power required to produce unity signal-to-noise ratio (SNR) as a function of the demodulation frequency.
Spin and Magnetic Moment of Silver-109m
Authors: Stinson G. M. , Pierce A. R. , Waddington J. C. , Summers-Gill R. G.
Published: April 2011

Atomic beam magnetic resonance has been used to study the 41-s isomeric state of 109Ag. The measured nuclear spin is 7/2 and the hyperfine interaction constant in the 2S1/2 electronic state is found to be 9550 ± 100 MHz. The special nature of the data also provides a direct evaluation of the nuclear magnetic moment, μI(corr.) = +4.27 ± 0.13 nuclear magnetons. The accuracy, however, is limited by the possibility of power shifts in the observed resonances and the error quoted is an estimate of this uncertainty. The moment is in closest agreement with theory if one assumes the state is the result of the coupling of three quasi-particles.
Remarks on Decoupling Procedures in Green's Function Theory of Ferromagnetism for S = 1/2
Authors: Ramos J. G. , Gomes A. A.
Published: April 2011

It is the purpose of this work to discuss, for an S = 1/2 ferromagnet, how recently proposed decoupling schemes may be obtained, the validity of the involved assumptions including them, and the consequences in the low-temperature range. It is suggested that the spurious T3 term present in almost all Green's functions approaches is connected to local kinematics violating treatments of the spin correlation.
Inertial Defect and Geometry of H2O in the State
Authors: Johns J. W. C.
Published: April 2011

Published rotational constants of the [Formula: see text] electronic states of H2O and D2O have been corrected for the effects of rotation electronic interaction. The corrected constants have been used to obtain a 'deperturbed' geometry which agrees with results obtained from a Frank–Condon analysis of the band intensities.
Magnetic Structure of Manganese Pyrophosphate, Mn2P2O7
Authors: Collins M. F. , Gill G. S. , Stager C. V.
Published: April 2011

The arrangement of the spins in antiferromagnetic manganese pyrophosphate at 4 °K has been determined by neutron diffraction from a powder specimen. The spins are in ferromagnetic sheets with the moment in each sheet aligned antiferromagnetically relative to its neighboring sheets.
Improved Estimate of the CP Violation Parameters from the Consequences of Unitarity
Authors: Gien T. T.
Published: April 2011

The improved approximate expressions for η+ −, η00, and Re ε are obtained with the model-dependent assumption of 2π saturation for the unitarity sum. The results are used to test again some models of CP non-invariance. In a certain model, the new value of [Formula: see text] is found to be closer to the originally estimated value based on Re ε as imput.
Properties of the 1.410 and 1.612 MeV Levels in 37Ar and the 1.727 MeV Level in 37Cl
Authors: Taras P. , Turcotte A. , Vaillancourt R. , Matas J.
Published: April 2011

The properties of the 1.410 and 1.612 MeV levels in 37Ar and the 1.727 MeV level in 37Cl were investigated. The levels in 37Ar were populated via the 37Cl(p,n)37Ar reaction and the level in 37Cl via the 37Cl(p,p′)37Cl reaction. The angular distribution and the linear polarization of the decay gamma rays of these levels were measured at incident proton energies of 3.98, 4.17, 4.38, and 4.81 MeV. The results of these measurements are consistent with a spin of 1/2 for the 1.410and 1.727 MeV levels, while they definitely establish the spin and parity of the 1.612 MeV level to be 7/2−. This last level has also been found to decay entirely to the ground state, with a multipolarity mixing ratio δ(E3/M2) = +0.22 ± 0.11. This level has properties quite similar to those of the 7/2− states in 35Cl and 37Cl, indicating that they may all arise from a 1f7/2 single-particle excitation.
Electron Paramagnetic Resonance in Cu2O Compared with Other Semiconducting Properties
Authors: Taylor J. C. W. , Weichman F. L. , McClung R. E. D.
Published: April 2011

Electron paramagnetic resonance spectra have been observed in single crystals of Cu2O at 4.2 °K. Six samples cut from the same starting material were individually heated under a wide range of vacuum conditions and comparison was made between the observed e.p.r. spectrum and the luminescence, activation energy, and photoconductivity in the same sample. No direct relationships between e.p.r. spectra and the luminescence and photoconductivity were found although a good correlation between the complexity of the e.p.r. spectra and the room temperature activation energy was observed.
Probing of Flow Fields with Shock Waves—The Swing Probe
Authors: Strachan J. D. , Ahlborn B.
Published: April 2011

The one dimensional equations governing shock propagation into inhomogeneous media have been developed to allow a shock to be used as a probe. Shock waves which collide with unknown gas or plasma flow fields suffer a change in velocity. Pressure, density, particle velocity, and local energy input at the edge of an unknown flow can be determined from the measurement of unknown flow. The steady variation of the velocity of strong probing shocks reveals details of the local velocity and density distributions inside the unknown flow field. One further result is the extension of the general theory of shock propagation into inhomogeneous media to cover the case when an energy source term appears at the front.
Spectroscopy of Perseid Meteors with an Image Orthicon
Authors: Millman P. M. , Cook A. F. , Hemenway C. L.
Published: April 2011

An image orthicon technique for recording meteors, developed some years ago by Hemenway at the Dudley Observatory, has recently been used at the Springhill Meteor Observatory, Ontario, for the recording of meteor spectra and combined with three other observational techniques—meteor radars, spectrographs, and a team of visual observers. Fifteen meteors, observed with the image orthicon during the August campaign in 1969, are here discussed out of a total of more than forty. Apparent visual magnitudes range from −1 to +3 and all 14 Perseid spectra in this group exhibit the oxygen green line at 5577 Å as well as other atomic lines normally found in the spectra of members of this shower. At the beginning of their trails all meteors show either a strong continuum, or evidence of band structure where the 1st and 2nd positive systems of N2 have been identified with reasonable certainty, while the first negative systems of N2+ and O2+, and the visible system of OH, are possible contributors.Measures of the 5577 Å line indicate a height spread from 120 to 95 km with a maximum near 106 km. After initial formation the intensity of this line increases for 0.2 to 0.5 s, after which it decays over periods up to 2 s. The decay constant for the 1S metastable state of neutral atomic oxygen is 0.76 s−1.The two chief advantages of the image orthicon technique are: its ability to record meteor spectra down to fainter thresholds of luminosity than in the case of conventional spectrography, and the time-resolution given by a recording of 15 complete frames per second.
On the Derivation of the Integral Equation for the Propagation of Light in Dielectric Crystals
Authors: Vlieger J.
Published: April 2011

A new derivation is given of the integral equation for the macroscopic polarization set up in a dielectric crystal by an incident light wave. The molecules are assumed to lie on the points of a perfect, simple lattice and to interact only via the retarded dipole–dipole interaction. The derivation is based on a direct averaging of the microscopic equations for the dipole moments induced by the incident wave and the dipole fields. The averaging is a space averaging with a weight function with a width Δ satisfying [Formula: see text], where a is the lattice constant and λ the wavelength of the incident field. The derivation is an application of Nijboer and De Wette's method for the evaluation of lattice sums.In contrast to the more indirect derivation given earlier by Hoek, (i) the present derivation is not based on an expansion in powers of the molecular polarizability, α, so that, e.g., there is no limitation to frequencies outside the resonance regions, and (ii) the integral equation is shown to be valid everywhere in the crystal except in a macroscopically negligible boundary layer of thickness Δ rather than λ. The latter improvement is crucial in the presence of superradiance.The integral equation is shown to be equivalent to the usual wave equation derived from Maxwell's phenomenological theory supplemented by the appropriate constitutive equations. An explicit expression is derived for the frequency dependent dielectric tensor in terms of rapidly convergent lattice sums.
Charge Radii of 20, 22Ne Determined from Elastic Electron Scattering
Authors: Moreira J. R. , Singhal R. P. , Caplan H. S.
Published: April 2011

The charge radii of 20, 22Ne have been measured by elastic scattering of electrons. The data have been analyzed in the first Born approximation as well as with a phase shift analysis. The results obtained are R(22Ne)/R(20Ne) = 0.976 ± 0.010. This anomaly is shown to be consistent with ground state deformations in 20, 22Ne.