bluuebunny/crossref_metadata_2025 huggingface dataset:
Optical pumping as a relaxation process
Authors: Vanier Jacques
Published: April 2011

A theory of optical pumping is given in which the interaction between the radiation and the ensemble of atoms is treated as a random perturbation. The theory gives the pumping rate and the light shift magnitude. The results are compared with those already published.
An anomaly in the specific heat below 3 °K of copper containing hydrogen
Authors: Waterhouse Neil
Published: April 2011

The specific heat of copper heated in hydrogen at 1040 °C has been measured over the temperature range 0.4 to 3.0 °K and found to be anomalous. The anomaly occurs in the same temperature range as the solid hydrogen λ anomaly which, in conjunction with evidence of ortho to para conversion of hydrogen in the sample, suggests the presence of molecular hydrogen in the copper. The anomaly reported by Martin for "as-received" American Smelting and Refining Company (ASARCO) 99.999+ % pure copper has been briefly compared with the present results. The form of the anomaly produced by the copper-hydrogen specimen has been compared with Schottky curves using the simplest possible model, that for two level splitting of the degenerate J = 1 rotational state of the ortho-hydrogen molecule.Maintenance of the copper-hydrogen sample at ~20 °K for approximately 1 week removed the "hump" in the specific heat curve. An equation of the form Cp = γT + (464.34/(θ0c)3)T3 was found to fit these experimental results and produced a value for γ which had increased over that for vacuumannealed pure copper by ~2%.
Rotational analysis of A–X1 bands of PbF
Authors: Singh O. N. , Srivastava M. P. , Singh I. S.
Published: April 2011

The rotational analysis of the four bands (0,0), (0,1), (0,2), and (1,0) of the A–X1 system of PbF has been carried out. The bands have been excited in a transformer discharge and photographed in the second order of a 35-ft concave grating spectrograph. The analysis has shown that the bands arise from a [Formula: see text] transition. The rotational constants of the upper and lower states have been determined.
Hydromagnetic radiation from electric and magnetic dipoles in the magnetosphere
Authors: Sundaram A. K.
Published: April 2011

This paper deals with the radiation characteristics of elementary electric and magnetic dipoles in a homogeneous, anisotropic, cold plasma of infinite extent with a uniform magnetostatic field. The cases treated include the electromagnetic sources taken parallel and perpendicular to the magnetostatic field. In all cases expressions for the field components are obtained which are valid at frequencies well below the ion cyclotron frequency. It is found that electric and magnetic dipole sources when oriented perpendicular to the magnetic field excite both ordinary and extraordinary modes. For the ordinary mode, the waves are guided in both directions within cones of small apex angle aligned with the static field. When the dipole sources are aligned with the magnetic field, it is found that the electric dipole excites only the ordinary mode leading to guided wave propagation, while the magnetic dipole excites only the extraordinary mode. In all cases the waves propagate at Alfvén speed. The radiation characteristics are isotropic for the extraordinary mode excited by the perpendicular electric dipole and are nearly isotropic for the aligned magnetic dipole. For other cases the radiated power is concentrated in opposite directions along the static field.
Forbidden absorption bands of O2 in the argon continuum region
Authors: Ogawa M. , Yamawaki K. R.
Published: April 2011

The absorption spectrum of O2 has been photographed in the argon continuum region with a 3-m vacuum spectrograph at a dispersion of 1.42 Å/mm. Based on the known rotational constants of the ground state, the rotational constants of the upper states have been determined for Tanaka progession (I), β–X3Σg−, progression (II), α1Σu+–X3Σ−, and those of a new band at 1144.6 Å. In a brief discussion of the upper electronic states, it is suggested that both the β state and the upper states of the 1144.6 Å band are 3Σu+ states and their electron configurations are (πg2p)(3pπ) and (πg2p)(4pπ), respectively, and also the α state is (πg2p)(3pπ)1Σu+.
EPR study of antiferromagnetic ordering in CrVO4
Authors: Elliston P. R.
Published: April 2011

The intensity and line width of the electron paramagnetic resonance have been studied above the Néel temperature in polycrystalline CrVO4. The intensity data give TN = 51 ± 1 °K. Both the intensity and line-width data suggest considerable short-range order above TN.
Coulomb excitation of 24Mg with 35Cl ions
Authors: Pelte D. , Häusser O. , Alexander T. K. , Evans H. C.
Published: April 2011

The Coulomb excitation of a thick 24Mg target was studied with 35Cl ions of 61, 57, and 52 MeV. The absolute cross section and the anisotropy of the angular distribution of the ground state transition from the 1.369-MeV state in 24Mg was measured, and their dependence on B(E2) and the quadrupole moment, Q, of the 1.369-MeV state was calculated. A B(E2) of 24.5 ± 2.2 Weisskopf units (W.u.) was deduced from the line shape of the 1.369-MeV gamma ray observed with a 40 cm3 Ge(Li) detector. The quadrupole moment determined from the anisotropy measurement was Q = −0.38 ± 0.16 b. From the cross-section measurement, Q = −0.47 ± 0.19 b was obtained using B(E2) = 24.5 ± 2.2 W.u. The dependence of this value of Q on B(E2) is discussed.
Planetary orbits for a moving Sun
Authors: Rastall Peter
Published: April 2011

The scalar theory of gravitation is known to be in agreement with observed planetary motions if the Sun is assumed to be stationary with respect to the preferred coordinate systems of the theory. We now assume that the Sun is moving, and we find that, unless its speed is improbably small, there are observable effects on the planetary orbits. The difficulty can be overcome if one assumes that the Newtonian charts are determined by the distribution of matter.
Concerning "A thought experiment violating Heisenberg's uncertainty principle"
Authors: Billette J. J. , Campillo C. , Lee C. , McConnell R. D. , Pariseau G. , Fischer G.
Published: April 2011

It is shown that "Robinson's thought experiment" does not violate Heisenberg's uncertainty principle, contrary to the claim of its designer.
Low-energy Bremsstrahlung X-ray spectra from a stable auroral arc
Authors: Wilson B. G. , Baxter A. J. , Green D. W.
Published: April 2011

During a rocket experiment launched to investigate cosmic X rays, the directional features and spectral characteristics of X rays from an auroral arc have been determined in the 1.6 to 10 keV energy range. The spectrum was best represented by a power law of slope −3.365 ± 0.07.
Imbibition in a cracked porous medium
Authors: Verma A. P.
Published: April 2011

In this paper, one special case of oil–water imbibition phenomena in a cracked porous medium of a finite length is analytically discussed. The equation for the linear countercurrent imbibition is a nonlinear differential equation whose solution has been obtained by a perturbation technique. For definiteness, specific results have been used for the relationship between relative permeability and phase saturation) impregnation function, oil–water viscosity ratio, and capillary pressure dependence on phase saturation due to Jones, Bokserman et al., Evgen'ev, and Oroveanu, respectively. An expression for the wetting phase saturation has been derived.
Stabilisation en puissance d'un laser à gaz carbonique monochromatique et monomode
Authors: Meyer Claude , Pinson Pierre , Rossetti Colette , Barchewitz Pierre
Published: April 2011

The set up of a stable and monochromatic CO2 laser has necessitated many systematic studies which are described.The observation of beating between modes led us to define the conditions of oscillation of a single mode. The use of a grating in the cavity gave a laser power on a single line. The construction of a single line, single mode laser gave us the possibility of ascertaining the constancy of the length of the cavity and of obtaining a power stability better than 1.5 × 10−2 during 1 h.
Gamma rays from the 3702 keV level in 25Al
Authors: Anyas-Weiss N. , Litherland A. E.
Published: April 2011

The decay modes of the 7/2−, 3702 keV level in 25Al have been studied at the Ep = 1490 keV resonance in the 24Mg(p,γ)25Al reaction. The decay gamma rays were observed using a 25 cm3 Ge(Li) detector. A previously unreported 2% transition from the resonance to the level at 2723 keV has been observed. The angular distribution of this gamma ray admits only a spin of 7/2 for the 2723 keV level. The lifetime of the 2723 keV level was measured with the Doppler shift attenuation method (DSAM) at the 1660 keV resonance and was found to be [Formula: see text]. The lifetime of the 5/2+, 1790 keV level has been measured using the DSAM and has been found to be [Formula: see text]. From Doppler shift measurements a lower limit for the lifetime of the 3/2+, 945 keV level of [Formula: see text] was obtained. From angular distribution measurements at the Ep = 1490 keV resonance, the following multipole mixing ratios have been measured: δ(R → 0) = 0.00 ± 0.02; δ(R → 1790) = −0.02 ± 0.02; δ(R → 2723) = 0.15 ± 0.30; [Formula: see text]; δ(1790 → 945) = −0.15 ± 0.05; δ(945 → 0) = 0.35 ± 0.10 or 1.7 ± 0.2; δ(945 → 451) = −0.15 ± 0.05 or 2.6 ± 0.4. Comparisons with data in the mirror nucleus 25Mg have been made.
Pole dominance calculation of πK scattering lengths
Authors: Lai C. S. , Kiang D.
Published: April 2011

The low-energy πK scattering is treated within the framework of the meson pole dominance with the inclusion of nonresonant S waves. The result obtained for the πK scattering lengths in the present method is somewhat different from that of current-algebra calculation.
The high-temperature Gruneisen constant of cubic lattices
Authors: Brown J. S.
Published: April 2011

An explicit formula is derived for the Gruneisen parameter γ∞ of a cubic crystal. The result which follows simply from a theorem of matrix algebra is illustrated by application to the 6–12 nearest-neighbor model of solid neon.
Weak self-masses, Cabbibo angle, and neutral currents
Authors: Daykin P. N. , Gourishankar Radha
Published: April 2011

The Cabbibo angle is determined from the requirement that weak self-masses be free of quadratic divergence in a weak interaction model with both charged and neutral currents. The value of the angle still seems to be in agreement with experiments.
Spectrum of the airglow between 4 and 8 microns
Authors: Bunn F. E. , Gush H. P.
Published: April 2011

The airglow spectrum between 4 and 8 microns observed from an altitude of 90 000 ft contains only features due to thermal emission of stable atmospheric constituents.
Scattering and depolarization of electromagnetic waves from a slightly rough dielectric layer
Authors: Fung A. K.
Published: April 2011

Scattering of a plane, horizontally polarized electromagnetic wave in any direction from a slightly rough, lossless layer is considered. The layer is rough on both sides and the medium below the layer is assumed perfectly conducting. Small-perturbation theory is used and first- and second-order results are obtained. It is found that waves scattered along nonspecular directions are intimately related to the Fourier spectra of the boundary surfaces of the layer. In addition to the familiar multiple scattering between layer boundaries, there is multiple scattering due to surface roughness. This was not intuitively expected since the roughness was assumed to be small.The phenomenon of wave depolarization is found to occur and to be present in all directions. In general, the depolarized scattered field components are of the first order except for scattering in the plane of incidence, where only second-order terms are present.Special cases of scattering from a single, slightly rough interface are also found.
Note on the bounds and approximations to the ground state energy of N-fermion systems derived from density matrix theory
Authors: Peat F. David
Published: April 2011

Certain lower bounds to the ground state energy of N-fermion systems have been derived in the literature using the properties of reduced density matrices.It is indicated that while some good approximations to the energy may be obtained by similar consideration the rigorous lower bound expressions lie too far below the exact energy to prove generally useful.
Continuum eigenfunctions in the neighborhood of singularities for a uniform hard-sphere gas
Authors: Rahman M.
Published: April 2011

Approximate solutions in the continuum region are obtained in the neighborhood of singularities both for the neutral thermalization problem and the classical hard-sphere gas problem by using a differential equation approach.
Wave-number dependence of the static screening function of an interacting electron gas. I. Lowest-order Hartree–Fock corrections
Authors: Geldart D. J. W. , Taylor Roger
Published: April 2011

The lowest-order Hartree–Fock contributions to the zero frequency screening function are examined for an interacting electron gas in its ground state. Computational methods are developed to treat singularities associated with the bare coulomb interaction and vanishing energy denominators of the many-body perturbation expansion. Numerical results are given. The wave-number dependence in the intermediate (k ~ kF) range differs considerably from that of previous estimates.
Inelastic scattering of 100 MeV protons from 12C using a Ge(Li) total-absorption proton counter
Authors: Horowitz Y. S. , Bell R. E.
Published: April 2011

A cooled Ge(Li) detector has been used as a total-absorption proton counter for the energy analysis of 100 MeV protons scattered from a target of natural carbon. An overall energy resolution of 0.5 MeV to 0.6 MeV (FWHM) was achieved. The differential cross sections for the excitation of the 4.43, 7.66, 9.64, 10.8, 11.8, 12.7, 14.1, 15.1, and 16.1 MeV levels have been measured at nine angles from 10 to 60° (lab). The angular distributions for the 10.8, 11.8, and 14.1 MeV levels represent the first measured proton-scattering data for these levels in the intermediate energy region (> 50 MeV). A qualitative discussion of the excited states is presented, based mainly on the shapes of the angular distributions. At large scattering angles (> 30°), the angular distribution for the 0+ level at 7.66 MeV deviates significantly from 0+ angular distributions measured in 24Mg and 28Si, suggesting different mechanisms of excitation of 0+ states in the p and s–d shells.
Oscillator strengths for helium
Authors: Cameron Stella , McEachran R. P. , Cohen M.
Published: April 2011

Oscillator strengths for 95 singlet and triplet s–p and p–d transitions in neutral helium have been calculated using analytical wave functions of the "frozen-core" type. Both length and velocity formulations of the oscillator strengths have been employed. Our results are generally in good agreement with the most accurate values available.
The decay of 2.9-day 97Ru
Authors: Cook W. B. , Schellenberg L. , Johns M. W.
Published: April 2011

NaI(Tl) and Ge(Li) detectors have been used singly and in a two-parameter configuration to study the gamma rays associated with the decay of 2.9-day 97Ru. Thirteen transitions have been observed and accounted for in a decay scheme involving levels at 96.4, 215.8, 324.4, 656.7, 785.1, 855.4, 969.7, and 994.4 keV. Spin and parity assignments are discussed.
Hydrodynamic mode of a magnetic heat energy. Application of the linear response theory to a simple magnetic system
Authors: Lee K. C.
Published: April 2011

The hydrodynamic mode of heat in a simple magnetic system has been studied using linear response theory. The initial thermal disturbance has been set up by mechanical means. Expressions for local thermodynamic quantities analogous to the fluid system have been obtained. These results are used for the derivation of the hydrodynamic equation for the one-dimensional spin-[Formula: see text]X–Y model for which exact equilibrium correlation functions are calculable. The local temperature satisfies the wave equation indicating the existence of second sound in this model.
Refractive indices of some carbonate minerals in the point dipole approximation
Authors: Cowley E. R.
Published: April 2011

The refractive indices of minerals with the calcite and aragonite structures are analyzed in the point dipole approximation to give values for the polarizabilities of the individual ions. It is found that the experimental measurements are consistent with several models for the polarizability of the carbonate group, but that the use of a single anisotropic polarizability for the whole group is unreliable. Emphasis is placed on the use of the Ewald transformation and on the correct use of symmetry to increase the efficiency of the calculations.
Sound absorption in hydrogen gas at 77 °K
Authors: Narayana H. , Woods S. B.
Published: April 2011

The absorption of sound in gaseous para-hydrogen and in two mixtures of para- and ortho-hydrogen has been measured at 77 °K by a pulse technique. The frequency was 3 MHz and, by varying the gas pressure, measurements were made at frequency/pressure ratios from 3 to 45 MHz atm−1. The absorption due to relaxation between the rotational and translational energy modes was separated from the classical absorption and the relaxation time for the rotational transition J = 0 → 2 in the para-hydrogen molecule was determined. In pure para-hydrogen the isothermal relaxation time is found to be 2.21 × 10−8 s atm, but it is found to be shorter in mixtures of para- and ortho-hydrogen. The results in pure para-hydrogen are in excellent accord with recent experimental work of others but the agreement in the para–ortho mixtures is not quite so precise.
Studies of the ionic ferromagnet (LaPb)MnO3. IV. Lattice distortion and ferromagnetism
Authors: Oretzki M. J. , Gaunt P.
Published: April 2011

The magnetization curve of the ferromagnetic oxides (LaPb)MnO3 can be fitted to a molecular field model if a quartic term in the magnetization is introduced into the magnetic exchange energy. A search is made for volume or distortion anomalies as one of the compounds, La0.62Pbo0.38MnO3, is heated through its Curie temperature. No anomalies sufficiently large to explain the magnitude of the quartic term are found and it is therefore concluded that the quartic term does not arise because of a volume-or distortion-dependent magnetic exchange energy.
Magnetic field dependence of relaxation rates of non-Kramers doublets
Authors: Walker M. B. , Williams F. I. B.
Published: April 2011

It was recently shown by one of the authors (MBW) that the second-order Raman process gives rise to an electron spin–lattice relaxation rate for non-Kramers ions varying as T5 at low temperatures. We determine here the magnetic field dependence of this relaxation process for a non-Kramers doublet. We find that, in contrast to the other Raman relaxation rates, the T5 rate has a frequency dependence [Formula: see text] where ω is the resonance frequency and Δ the zero-field splitting of the doublet. The magnetic field dependences of the various relaxation rates are shown to be consequences of the time-reversal symmetry properties of the non-Kramers doublet.
Note on the surface impedance and the transmission of radiation through metal slabs
Authors: Cochran J. F.
Published: April 2011

An arbitrary electric field distribution in a metal slab in a uniform magnetic field can be written as a linear combination of four functions each of which satisfies Maxwell's equations for particularly simple boundary conditions. In particular, if the slab is thick compared with the skin depth of the radiation, δ, and if (ω/c)δ « 1, then the reflection and transmission coefficients for the slab are proportional to Gx(0), Gy(0), Gx(d), Gy(d) respectively, where Gx(z), Gy(z) are the electric field distributions generated in a slab bounded by the planes z = 0, z = d by a unit alternating magnetic field applied to the surface z = 0 and directed along y.
Removal of iron from gold
Authors: Walker C. W. E.
Published: April 2011

The study of dilute gold alloys at low temperatures has been hindered by the overshadowing effect of trace amounts of Fe. Its removal to less than 0.1 p.p.m. atomic has been achieved by treatment with chlorine gas at 850 °C, which is in a temperature range where gold and chlorine do not react.
Ionic conductivity of potassium chloride crystals
Authors: Chandra Suresh , Rolfe John
Published: April 2011

The electrical conductivity of single crystals of potassium chloride was measured as a function of temperature, and as a function of the amount of strontium chloride or potassium carbonate impurity. The results were analyzed by using a least-squares curve-fitting computer program in which the basic assumption was that conductivity was due entirely to the motion of separated anion and cation vacancies (Schottky defects). Coulomb interactions between charged defects were allowed for by using Debye–Hückel theory. With the exception of the conductivity of pure crystals very near the melting point, experimental conductivity measurements agreed with values calculated from the following parameters: Schottky-defect formation enthalpy hs = 2.59 eV, entropy ss = 9.61k; positive ion vacancy migration enthalpy Δh1 = 0.73 eV, entropy Δs1 = 2.70k; negative ion vacancy migration enthalpy Δh2 = 0.99 eV, entropy Δs2 = 4.14k; association of divalent cations and positive ion vacancies enthalpy χ = 0.58 eV, entropy η = 1.30k.
Electronic spectrum of the BF molecule
Authors: Caton R. B. , Douglas A. E.
Published: April 2011

The electronic absorption and emission spectrum of BF has been photographed at high resolution from 900 to 11 000 Å. In this work, many new electronic states have been found and corrections have been made to earlier work. The ionization potential has been determined to be between 89 635 and 89 680 cm−1, with the most probable value being 89 650 cm−1. Tables of the vibrational and rotational constants of all the known states of BF are presented. All but two of the excited states of BF have been classified as Rydberg states and have been assigned to Rydberg series. The interactions between the various Rydberg states are discussed.
The emission probability of the 121.2 keV γ ray in the decay of 147Pm
Authors: Mowatt R. S. , Merritt Janet S.
Published: April 2011

The emission probability, Pγ, of the 121.2 keV γ ray in the decay of 147Pm has been measured to be (2.7 ± 0.2) × 10−5 gammas per disintegration. The γ-ray counting rate for 147Pm sources was determined using a Ge(Li) planar diode and calibrated sources of 57Co which emit a 122.0 keV γ ray. The 147Pm disintegration rate was determined by the 4πβ–γ tracer method employing 46Sc as the tracer.
Extended moment theorem for resonance line shapes
Authors: Frank Barry
Published: April 2011

A recently-derived theorem, dealing with moments of line shapes arising from decoupled Green's function equations, is extended. The extended theorem simplifies moment calculations when approximations are made simultaneously at several stages of the hierarchy of equations. Approximations may now be made both in higher-order Green's functions and in thermal averages. Certain points in the application of the theorem to Hubbard decoupling and to Tomita and Tanaka decoupling are also discussed.
Perturbation of the D lines of atomic sodium trapped in inert-gas matrices
Authors: Duley W. W.
Published: April 2011

Lennard–Jones 6–12 potentials have been used with a configurational coordinate model to calculate the shift of the Na 32S → 32P transition for Na trapped in a variety of sites in solid Ar, Kr, and Xe matrices at 4°K. Multiplet structure in these systems is shown to be consistent with trapping at several distinct sites.
High-field current fluctuations in n-type germanium
Authors: Hart L. G.
Published: April 2011

The work reported here is an investigation of high-frequency electrical noise in n-type germanium at 77 K under a high, pulsed electric field.Previous studies of nonequilibrium noise were made of the fluctuating current normal to the electric field, in an investigation of the thermal component of the hot-electron velocity distribution, whereas in this work, the current fluctuations in the field direction are studied, with no attempt made to isolate the thermal contribution.The spectrum of the current fluctuations is taken as uniform over the range from 30 to 70 MHz, on the basis of the measurements made at these two frequencies, so that effects of carrier population fluctuations due to generation–recombination and trapping could be presumed to be small.The dominant feature of the results is the anisotropy of the noise temperature, which was interpreted as due principally to fluctuations in the [Formula: see text] valley populations, when valley drift velocities are unequal. For equal valley drift velocities, only the thermal component is present.
Electron–nuclear double resonance measurement of hyperfine interactions in Eu2+:CaWO4
Authors: Kiefte H. , Harvey J. S. M.
Published: April 2011

The hyperfine interactions in Eu2+ located substitutionally in CaWO4 have been accurately measured at a temperature of 4.2 °K by the method of electron–nuclear double resonance. These measurements were made in an attempt to determine the effects of the crystal field on the hyperfine interactions by comparison with results obtained for atomic Eu and Eu2+ in CaF2.The results have been fitted with a 12-parameter hyperfine Hamiltonian. Four of these parameters are used to represent an anisotropic quadrupole interaction and three to represent an anisotropic contribution of the form J3I. It is found that the spherically averaged quadrupole interaction is shifted by almost 20% from its value in CaF2. The nuclear g factor is also found to be shitted and anisotropic. These results are discussed in terms of a crystal-field induced shielding of the nuclear moments.
Continued fraction representation for slow neutron scattering. II
Authors: Sears V. F.
Published: April 2011

The calculation of slow neutron scattering cross sections for simple classical liquids by means of Mori's continued fraction representation was discussed in a previous article on the basis of the long-time approximation. In the present work it is shown that by going beyond the long-time approximation one can eliminate certain difficulties that arose in the previous work. This new approach yields results equivalent to those found by Kadanoff and Martin, and others, from linear response theory. Numerical calculations are made for liquid argon and compared with available experimental data.
Electronic absorption spectrum of the cyclopentadienyl radical (C5H5) and its deuterated derivatives
Authors: Engleman Jr. R. , Ramsay D. A.
Published: April 2011

The spectrum first observed by Thrush during the flash photolysis of cyclopentadiene has been reinvestigated using deuterated compounds. Eight different spectra have been observed and have been assigned to the isotopic species: cyclopentadienyl-d0, -d1, -1,2-d2, -1,3-d2, -1,2,3-d3, -1,2,4-d3, -d4 and –d5. The isotope shifts and the absence of further deuterated species establish unequivocally the assignment of the carrier, and show furthermore that the five hydrogen atoms and five carbon atoms are effectively equivalent.
Study of the reaction 35Cl(n,γ)36Cl
Authors: Hughes L. B. , Kennett T. J.
Published: April 2011

The gamma radiation from the 35Cl(n,γ)36Cl reaction has been studied using a Ge(Li) spectrometer. A total of 130 gamma-ray transitions was observed with an average precision of 2 keV. The neutron separation energy was found to be 8580.6 ± 1.0 keV. An examination of the partial radiative widths revealed that the ratio of E1 to M1 radiation agreed well with the ratio obtained from other measurements of E1 and M1 transition rates but the absolute values were enhanced by a factor of 10.
Specific heat below 3 °K of copper–gold alloys
Authors: Martin Douglas L. , Waterhouse Neil
Published: April 2011

Specific heat measurements were made between 0.4 and 3.0 °K on the disordered and two ordered phases of the equiatomic alloy CuAu, and also on CuAu3 in the disordered and partially ordered condition. The two samples of the disordered equiatomic alloy measured were found to be unstable, the specific heat on successive measurements slowly changing towards the values obtained for the ordered phase CuAu II. This is a remarkable result because all previous work has shown that the ordered phase formed below 385 °C is CuAu I. The first sample of CuAu I measured showed a distinct 'bump', with the maximum at about 0.7 °K, superimposed on the normal specific heat. A second sample did not show this 'bump' but the specific heat remained slightly anomalous. The nuclear specific heats of the ordered phases CuAu I and CuAu II and the partially ordered CuAu3 are higher than those of the respective disordered phases, supporting the hypothesis that the nuclear term is a quadrupole effect. Taking the present results in conjunction with those of Martin on Cu3Au, it is found that the electronic specific heats of the disordered alloys are fitted reasonably well by Stern's 'charging' theory. Ordering reduces the electronic specific heat by a few percent except for CuAu I where it is increased. The low-temperature limiting Debye temperature is increased by a few percent on ordering except for CuAu I where it is decreased. The Debye temperature changes are consistent with room-temperature Young's modulus measurements on copper–gold alloys. Otherwise it will be noted that the behavior of CuAu I is rather singular.
The 4550 Å band system of glyoxal. II. Vibration–rotational analyses for 12 bands of C2H2O2
Authors: Birss F. W. , Brown J. M. , Cole A. R. H. , Lofthus A. , Krishnamachari S. L. N. G. , Osborne G. A. , Paldus J. , Ramsay D. A. , Watmann L.
Published: April 2011

Rotational analyses have been performed for 12 bands of the 1Au–1Ag (π*–n) transition of glyoxal. Approximately 15 000 lines have been assigned, and rotational and vibrational constants obtained by computer methods. The vibrations investigated are ν2′ (CO stretching), ν4′ (C–C stretching), ν5′ and ν5″ (CCO bending), and the torsional levels with ν7 ′ = 1–4 and ν7″ = 1–3. A Coriolis interaction has been found involving the vibrations ν7 (au) and ν12 (bu). Some weak anharmonic interactions have also been identified.
Level structure of 35Cl from the 32S(α,pγ)35Cl reaction
Authors: Hooton B. W. , Häusser O. , Ingebretsen F. , Alexander T. K.
Published: April 2011

Proton–gamma coincidences from the reaction 32S(α,pγ)35Cl at Eα = 10.975, 11.960, and 12.120 MeV have been measured, using method II of Litherland and Ferguson. Twelve previously unreported levels between 3.94 and 6.40 MeV excitation energy have been found. The spins of four levels, 1.763 (5/2), 2.646 (7/2), 3.945 (9/2), and 4.885 (7/2), have been determined. Possible spins have been assigned to 12 of the other levels. Branching ratios and γ-ray multipole mixing ratios for all the levels studied are given.
Nouvelle méthode pour le gaz d'électrons
Authors: Simard P. A. , Hoc N. Quang
Published: April 2011

A new method is presented for the electron gas. A potential including the ring cross insertions and the usual Hartree term is obtained. The summation of these insertions is done in such a way that the infrared divergence of the Coulomb interaction is overcome. Numerical iterations are performed for this potential and a gap is found at the Fermi surface. This gap is a function of the density.
Decay of 97Zr and its daughter 97Nb
Authors: Arad B. , Prestwich W. V. , Lopez A. M. , Fritze K.
Published: April 2011

The energies of the gamma lines following the β decay of the 17 h 97Zr isotope and its 72 min daughter were precisely measured. With these results, the level scheme of 97Nb, as derived by Siivola and Graeffe, was essentially confirmed except for minor changes and more refined energies. The level scheme of 97Mo as derived by Graeffe and Siivola was modified and a few level spin and parity assignments were tentatively made.
The so-called fourth indeterminacy relation
Authors: Bunge Mario
Published: April 2011

The indeterminacy relation between time and energy, suggested by Bohr on the basis of a thought experiment, is shown not to belong to the quantum theory. It is argued that the incorporation of that formula into a theory would require a basic departure from present day physics, consisting in representing time by a suitable operator. It is suggested that the formula be dropped altogether.
Comments on the departures from Matthiessen's rule in monovalent metals
Authors: Berry R. J.
Published: April 2011

The departures from Matthiessen's rule predicted by Sondheimer for monovalent metal alloys are examined in greater detail, particularly with regard to their dependence on solute concentration.
Multiphoton ionization in atomic gases with depletion of neutral atoms
Authors: Chin S. L. , Isenor N. R.
Published: April 2011

An expression for the number of ions formed by multiphoton ionization of atoms at the focus of a Q-switched laser beam is derived assuming a rate given by existing perturbation treatments. Depletion of neutral atoms has the effect of indicating a lower than expected value for the number of photons absorbed. It is concluded that discrepancies between existing experimental data and perturbation results could be accounted for by such depletion.
Dislocation-enhanced diffusion in silver single crystals
Authors: Lai C. T. , Morrison H. M.
Published: April 2011

An electrolytic sectioning technique has been used to measure self-diffusion coefficients in silver single crystals in the temperature range 300–800 °C. The results are analyzed in terms of diffusion through the crystal lattice, enhanced by diffusion along dislocations.
Exact high temperature series expansions for the XY model
Authors: Betts D. D. , Elliott C. J. , Lee M. H.
Published: April 2011

A method is developed for the exact high temperature series expansion of thermodynamic properties of the spin 1/2 XY model of ferromagnetism or of a quantum lattice gas. Eleven coefficients in the specific heat series for the f.c.c. and b.c.c. lattices and nine coefficients in the series for the fluctuation in the long range order for the f.c.c., b.c.c., and s.c. lattices are calculated. From the fluctuation series the critical temperatures Kc−1 ≡ kTc/J are estimated to be 4.520, 2.902, and 2.02 respectively, while the critical index for the square of the fluctuation in the long range order is γ = 1.35.
Half-life measurements on 29P and 33Cl
Authors: Scanlon P. J. , Crabtree D.
Published: April 2011

The half-life values for the β+ emitters 29P and 33Cl reported in the literature show a wide variation (4.6 ± 0.2 to 4.19 ± 0.02 s for 29P and 2.9 ± 0.1 to 2.51 ± 0.02 s for 33Cl). We have remeasured these activities via the Si(p,γ)P and S(p,γ)Cl reactions with protons from a 3 MV Van de Graaff. The decay positrons were detected in a solid-state detector telescope and the time distribution of the pulses was determined with a multiscaler controlled by a crystal clock. Data were analyzed by an iterative least-squares procedure and by the Fourier transform method. Values obtained were 4.15 ± 0.03 s for 29P and 2.47 ± 0.02 s for 33Cl.
Fundamental infrared absorption of H2 in solid Kr and of D2 in solid argon
Authors: Remigis J. De , Welsh H. L.
Published: April 2011

The fundamental infrared absorption band of H2(D2) has been studied in the dilute solid solutions H2–Kr and D2–Ar, and the results are compared with previous data for H2–Ar. The spectrum consists of combination tones of molecular and lattice transitions; the lattice transition frequencies are (112, 22), (106, 16), and (79, 22) cm−1 for H2–Ar, H2–Kr, and D2–Ar, respectively. The previous assignment of the intense higher-frequency transition to the localized vibration of the impurity molecule on a substitutional lattice site is confirmed. The weaker lower-frequency transition is evidently due to an impurity-induced phonon transition of the host lattice.
Upper bounds to the overlap between approximate and exact wave functions
Authors: Cohen Maurice , Feldmann Tova
Published: April 2011

Rigorous lower and upper bounds to the eigenvalues E of a quantum-mechanical system with Hamiltonian operator H are derived from the Gramian determinant of a set of suitably chosen functions. This procedure, which also yields a rigorous upper bound to the overlap between a given trial function and the corresponding (unknown) exact eigenfunction, is shown to be equivalent to a generalization of the classical procedure of Weinstein. In the absence of a rigorous lower bound to the overlap, the present procedure provides a practical method of assessing the influence of the ground state on a given trial function for an excited state.
Correlation analysis of radio-auroral scatter signals
Authors: Palmer F. H. , Moorcroft D. R.
Published: April 2011

Very high frequency radio-auroral scatter signals are regularly observed on an Ottawa–London (Ontario) backscatter circuit operating at 40.35 MHz. For three of these events the scale size and drift velocity of the scattered field at the receiving site were determined by a correlation analysis of the signals received at spaced antennas. The overall east–west extent of the scattering regions was determined from the scale-size measurements. At least two types of event were observed. One type results from scattering by extended regions with horizontal dimensions greater than 200 km and having minimum drift velocities of a few hundred m/s. The second type of event results from simultaneous scattering by a number of independent regions, each having its own drift speed and direction. These regions have drift velocities in excess of 1 km/s and horizontal dimensions often less than 30 km.
Laser-induced emission from glyoxal
Authors: Holzer W. , Ramsay D. A.
Published: April 2011

Approximately 50 bands have been recorded in emission from glyoxal excited with the 4765, 4880, 4965, 5017, and 5145 Å lines of an argon ion laser. Most of the stronger bands are readily assigned to the 1Au–1Ag (π*–n) and 3Au–1Ag (π*–n) systems. Seven bands are tentatively assigned to a new band system, probably a second singlet π*–n system. One Raman band has been observed. The new measurements give ν1″ = 2843 cm−1, ν2″ = 1745 cm−1, and ν4″ = 1065 cm−1.
Structure of a singly ionizing current sheet propagating in a low density gas
Authors: Pert G. J.
Published: April 2011

The structure of a singly ionizing current sheet is examined under steady-state conditions. Convergent solutions are only found in the presence of ambient transverse magnetic and electric fields. A collision-free model is used to approximate to the ionization region in the front. This solution is cut off at the electron mean free path and matched to a collision-dominated magnetohydrodynamic two-fluid calculation for the back of the sheet. The conditions for the establishment of a steady state are examined for these solutions.
Nonlinear resonant ion heating in a magneto-plasma
Authors: Jayasimha P. , Thompson W. B.
Published: April 2011

A calculation is presented of the power absorption by ions in a hot plasma through a nonlinear process in which a wave near the ion cyclotron frequency is excited by the mixing of two high-frequency waves. The high-frequency waves are so selected as to match vacuum waves at a plasma–vacuum boundary.
Modification of Friedel oscillations by a magnetic field. II
Authors: Glasser M. L.
Published: April 2011

The density perturbation δρ(r) about a delta-function impurity potential is analyzed for a degenerate electron gas in the effective-mass approximation. Results are presented for a wide range of field strengths and all distances from the impurity beyond the Debye–Thomas–Fermi screening length.
Mechanism of a CO–N2 laser. I. Study of the vibrational populations
Authors: Legay F. , Legay-Sommaire N. , Taïeb G.
Published: April 2011

A laser operating on the vibrational–rotational levels of CO populated by active nitrogen has been built and studied by infrared spectroscopy. The operational characteristics and the importance of the nature of the walls and their condition are discussed. The population of each vibrational laser level has been deduced from the gain measurement of each laser line. The mechanism of the population inversion is described in terms of the theory proposed by Treanor, Rich, and Rehm, assuming that the population of CO vibrational levels is ensured by a vibration–vibration transfer from vibrationally excited nitrogen molecules.
Range of order in antiferromagnets with next-nearest neighbor coupling
Authors: Stephenson John
Published: April 2011

A general argument is presented that a change in the nature of the short-range order will occur above a precisely located temperature TD, the disorder point, for a wide class of magnetic models. The range of order is calculated exactly for two-dimensional asymmetric Ising triangular and union-jack lattices. A sharp cusp in the range of order vs. temperature graph occurs at the disorder point. It is proposed that measurements of the range of order by neutron-diffraction techniques be made on suitable antiferromagnetic crystals to determine whether a disorder point can be detected. It is suggested that two-dimensional antiferromagnets, such as manganese formate dihydrate, may exhibit disorder points.
Third-order corrections to the Hartree–Fock approximation for the binding energy of 4He
Authors: Kreuzer H. J.
Published: April 2011

We present third-order calculations of the binding energy of 4He with an effective (finite) nucleon–nucleon interaction of the Hamada–Johnston type. The intermediate (unoccupied) states are approximated by plane waves in a first calculation and in a second by oscillator functions. In both approximations third-order graphs contribute only a few percent of the second-order terms to the binding energy.
Solar neutron flux in the energy range 20–160 MeV
Authors: Kim C. Y.
Published: April 2011

An attempt to measure the flux of high-energy solar neutrons was made by measuring the difference in flux from the direction of the sun and from the symmetrical direction about the zenith, using oriented nuclear emulsions flown by balloon on July 30, 1966 from Fort Churchill, Manitoba.An excess of (2.2 ± 2.5) × 10−2 neutrons cm−2 s−1 was observed from the direction of the sun in the energy region of 20–160 MeV. On the day of the flight the sunspot number was 63, and no major solar flares were reported.
Propriétés de symétrie des symboles à 3j de SU(n)
Authors: Derome Jean-Robert , Jakimow G.
Published: April 2011

For an arbitrary compact group it is not in general possible to choose the 3j-symbol [Formula: see text] such that its absolute value is invariant under every permutation of the j's and of the corresponding m's. For SU(3) this choice is possible. It is shown here that for SU(n) such a choice is not possible.
Nucleation of parasite crystals in constitutionally supercooled water on the surface of growing ice
Authors: Kvajić G. , Brajović V.
Published: April 2011

Nucleation of parasite crystals in front of an ice mosaic bicrystal growing vertically upwards from a solution is observed during the freezing of a dilute salt solution. It appears in the presence of a constitutionally supercooled layer ahead of a solid–liquid interface and shows a curious dependence of parasite and mother crystal on their crystallographic orientations. The formation of parasites is also observed in front of the Cv crystals growing downwards, i.e. the crystals with the C axis being perpendicular to the solid–liquid interface.
Mouvement plan dans un potentiel central logarithmique: propriétés analytiques de l'orbite
Authors: Celles Michel de
Published: April 2011

Plane motion in a central logarithmic potential is studied for the purpose of using the cylindrical condenser as an electrostatic mirror. It is shown that the quadrature for the orbit can be transformed to a contour integral. The contour is such that the orbit dependence on energy and angular momentum does not involve the limits of integration. This makes it unnecessary to calculate the apsidal distances separately before integrating. Expansions for the orbit formula can then be obtained in a simple manner, as only the integrand depends on energy and angular momentum. One example of expansion is given and its properties are studied.
Fine structure in highly excited analog states
Authors: Goulard B. , Fallieros S.
Published: April 2011

The nature of the fine structure surrounding analog states at relatively high excitations is discussed and compared with the corresponding structure at lower energies.
Altitude profile of airglow hydroxyl emission
Authors: Harrison A. W.
Published: April 2011

A rocket-borne cooled (S-1) filter photometer was flown from Resolute Bay, Northwest Territories 75° N during geomagnetically quiet conditions. The derived altitude profile of the (6–2) hydroxyl band emission shows a peak at 95 km. An airglow background of 2.7 R A−1 or less at 8380 A is reported for altitudes above 125 km.
Raman spectra and lattice dynamics of the α phases of nitrogen and carbon monoxide crystals
Authors: Anderson A. , Sun T. S. , Donkersloot M. C. A.
Published: April 2011

The Raman spectra of polycrystalline α-nitrogen and α-carbon monoxide have been recorded at 18 °K, using argon–ion and helium–neon laser excitation. Previously undetected peaks at 60 cm−1 for N2 and 90.5 cm−1 for CO are assigned as librational modes, and splitting of the stretching mode in nitrogen is observed for the first time. Spectral features in both the intramolecular and lattice regions are assigned in accordance with accepted crystal structures, and their frequencies compared with those obtained from calculations based on a spherical Lennard–Jones potential and quadrupole–quadrupole interactions between the molecules.
Gilbert-like dispersion relations for the form-factors
Authors: Kamal A. N.
Published: April 2011

New dispersion relations are obtained for the form-factors. A sum rule for the r.m.s. radius is derived and tested.
A satellite measurement of the relative abundance of relativistic cosmic ray LH nuclei
Authors: Ely John T. A.
Published: April 2011

A Cerenkov–scintillator telescope was flown on the low altitude polar orbiting OV1-10 satellite. Charge resolution was accomplished in the Z = 9 to 17 range for energies above ~.6 BeV/nucleon. The data indicate an even–odd ratio for the integral energy spectra of these nuclei which decreases from 6 to 3 as the threshold increases from.6 to about 3 BeV/nucleon. This behavior is shown to be consistent with a positive energy dependence of path length. The measurements are presented and compared with the other published satellite results and one balloon experiment.
Surface excitations in the random phase approximation
Authors: Harris John , Griffin Allan
Published: April 2011

Density fluctuations in inhomogeneous systems are treated in the RPA using the Kadanoff–Baym Green's function method. In our analysis, the Wigner distribution function plays an important role. Well-known results for surface plasmons in one- and two-component plasmas are very easy to derive. A brief discussion is given of surface modes in systems for which the interaction is of short range.
Transition rates in 29P
Authors: Monahan C. F. , Evans H. C. , Montague J. H. , Paulson W. R. , Zuk W. M.
Published: April 2011

Lifetimes of three of the low-lying excited states in 29P, populated in the 28Si(p,γ) reaction, have been determined using the Doppler shift attenuation method. The mean lifetimes of states at 4.085, 1.956, and 1.385 MeV were found to be 15 ± 4, 370 ± 80, and 200 ± 60 fs.Angular distribution measurements have also been performed on gamma rays resulting from the decay of the 4.085 MeV resonance level. The decay was found to go via states at 3.107 MeV (3%), 1.956 MeV (54%), and 1.385 MeV (43%). The spin of the resonance level was uniquely assigned as 7/2 and the multipole mixing ratios of the 2.129 and 1.385 MeV transitions as + 0.17 ± 0.05 and + 0.303 ± 0.050 respectively. The consequent transition rates indicate that the parity of the resonance level is positive.