bluuebunny/crossref_metadata_2025 huggingface dataset:
Properties of low-lying states in 43Sc
Authors: Ball G. C. , Forster J. S. , Ingebretsen F. , Monahan C. F.
Published: April 2011

The 40Ca(α, pγ)43Sc reaction at Eα = 11.8 to 15.5 MeV has been used to investigate the level structure of 43Sc below 4.2 MeV excitation. Level energies and decay schemes were determined from proton–gamma coincidence spectra obtained using an annular surface barrier detector positioned near 180° and two 40 cm3 Ge(Li) detectors. Angular correlations were measured in the same configuration using an array of six 12.7 × 15.2 cm NaI(Tl) detectors mounted on the Chalk River LOTUS goniometer. Twelve new levels were observed in 43Sc and information on the spins, branching ratios, and gamma-ray multipole mixing ratios of these and several other excited states has been obtained. The results are compared with recent theoretical predictions of Johnstone. In particular, levels at 1931 and 2552 keV, 1830 keV and 1883 keV have been tentatively assigned as the 9/2+ and probable 11/2+ members of the kπ = 3/2+ band, the (fp)3, Jπ = 11/2− state, and the 9/2− member of the kπ = 3/2− band, respectively.
On the single-particle-energy spectrum of a Λ particle in nuclear matter
Authors: Chong K. F. , Nogami Y. , Satoh E.
Published: April 2011

The single-particle-energy spectrum of a Λ particle in nuclear matter is examined in the independent-pair approximation, by assuming nonlocal separable potentials for the ΛN interaction. Effects of short-range repulsion in the ΛN interaction on the Λ binding are also examined in terms of separable potentials of rank two.
The 1Π–X1Σ+ band system of AsP
Authors: Harding L. , Jones W. E. , Yee K. K.
Published: April 2011

The rotational analysis of the 2–0, 1–0, 0–0, 0–1, and 0–2 bands of the molecule AsP is reported. The band system corresponds to a 1Π–1Σ+ transition. Molecular constants of the lower and upper states are found to be[Formula: see text]Several perturbations have been found in the upper vibrational levels.
Low temperature frequency dependence of the electron spin resonance absorption in heavily phosphorus-doped silicon
Authors: Hedgcock F. T. , Raudorf T. W.
Published: April 2011

Electron spin resonance (ESR) measurements have been made on a phosphorus-doped silicon specimen (n = 1.38 × 1019/cc) in the liquid helium temperature range. A single line with a g factor of approximately 2 was observed for resonant magnetic fields of 540, 3230, and 12 590 G at 1517, 9010, and 35 200 MHz respectively. The experimentally determined magnetization is compared with the magnetizations expected from the following sources: (a) un-ionized charge carriers or local magnetic moments obeying a Curie law, (b) mobile carriers experiencing an exchange interaction with local magnetic moments, and (c) mobile charge carriers showing only Pauli paramagnetism. The magnetization derived from the ESR data exhibits a linear dependence with magnetic field and no temperature dependence. This is consistent with the Pauli paramagnetism expected for mobile charge carriers in the absence of any interaction with local moments.
Muonic X rays and capture γ rays in 89Y
Authors: Kessler D. , McKee R. J. , Hargrove C. K. , Hincks E. P. , Anderson H. L.
Published: April 2011

The main mu-atomic transition energies in 89Y were measured with a high-resolution Ge(Li) spectrometer. The nuclear charge parameters of yttrium were derived by fitting the observed transition energies to those obtained by numerically solving the Dirac equation, using a radially symmetric Fermi charge distribution. The line intensities were also measured and shown to agree reasonably well with the results of a cascade calculation. Finally, we measured the energies and intensities of the most prominent capture γ rays. Most of these γ rays could be assigned to known transitions in the strontium isotopes 86 through 89.
Quadrupolar Nuclear Spin–Lattice Relaxation in R2MX6 Compounds
Authors: Armstrong Robin L. , Jeffrey Kenneth R.
Published: April 2011

The Van Kranendonk theory of quadrupolar nuclear spin–lattice relaxation is adapted to the case of the X nuclei in R2MX6 compounds as observed in a pure nuclear quadrupole resonance experiment. The formula derived for the spin–lattice relaxation time is discussed with reference to experimental data for three R2PtCl6 compounds. The internal modes of the PtCl6 complex are shown to be relatively unimportant for spin–lattice relaxation of the chlorine nuclei. The experimental data yield average rotary mode frequencies of the PtCl6 complex in K2PtCl6, Rb2PtCl6, and Cs2PtCl6. The results are in good agreement with the theoretical predictions.
Friedel Sum Rule: Partition Function Approach
Authors: Sinha Om P.
Published: April 2011

The Friedel sum rule has been derived using a grand canonical ensemble of electrons in the scattering states. The method, while illustrating the use of the statistical method of the grand canonical ensemble, clarifies the exact nature of the constraint which gives rise to this sum rule, viz. the charge neutrality of the entire crystal. An extra term has been found which cancels the contribution to the Friedel sum from the phase shifts at k = 0. This cancellation term is shown to exist in the conventional derivation if done more carefully, thus emphasizing the care needed when a finite result is sought by subtraction from two rather infinite terms. An expression for the excess charge density valid within the range of the scattering potential has been derived.
Decay Schemes for the Isomers of 148Pm and the Cross Sections for their Production by Neutron Capture in 147Pm
Authors: Mowatt R. S. , Walker W. H.
Published: April 2011

The γ-ray spectra arising from the decay of 41-day 148Pmm and 5-day 148Pmg produced by the irradiation of 2.6-year 147Pm in a thermal reactor neutron flux have been measured with a Ge(Li) detector. The absolute probabilities for γ-ray emission were determined from an analysis of the spectra and used to construct an improved decay scheme for the two isomers and to obtain their production cross sections. The 147Pm thermal neutron cross sections obtained after making a small correction for epithermal capture are 84 ± 10 b and 72.4 ± 3.0 b for the production of the 148Pmg and 148Pmm activities respectively, in good agreement with the results of Fenner and Large, but significantly smaller than other recent measurements.
Application of Truncated Multipolar Expansion Pair Functions in Atomic Structure Calculations. II. Irreducible Tensor Operator Form of the Strongly Orthogonal Pair Functions. Reduction of Orthogonality Constraints
Authors: Jankowski K.
Published: April 2011

The truncated multipolar expansion pair functions (TMEPF) defined recently by Jankowski have been used to formulate an approach which takes into account correlation effects within a pair of electrons in the presence of an N electron sea in a closed shell configuration. An irreducible tensor operator form of the strongly orthogonal pair function components has been derived. The analysis of the expressions obtained leads to a systematic reduction of the orthogonality constraints to be imposed on this class of trial functions. The results of this analysis for several types of pair functions have been given. Finally, the method of calculation of matrix elements between orthogonally projected pair function components in terms of radial integrals is presented.
Measurements of Internal Conversion and Internal Pair Formation Coefficients in Lead Isotopes
Authors: Allan C. J.
Published: April 2011

The decay of 205Bi, 206Bi, and 207Bi have been studied using Ge(Li) detectors for γ-ray detection and a trochoidal β-ray spectrometer for conversion electron and internal pairs detection. Numerous conversion coefficients and internal pair formation coefficients have been determined. Using γ−γ coincidence the positions of the 1844, 1878, and 1903 keV transitions in the decay of 206Bi have been determined.
Inelastic Scattering of Thermal Neutrons from Liquid Helium
Authors: Cowley R. A. , Woods A. D. B.
Published: April 2011

The scattering of neutrons by liquid helium has been studied over a wide range of wave-vector transfers, 0.2 < Q < 9.0 Å−1, and energy transfers [Formula: see text]. The measurements were performed with both a time-of-flight rotating crystal spectrometer and a triple-axis crystal spectrometer. The scattering at 1.1 °K showed a sharp one-phonon peak and a broad diffuse background. Measurements have been made of the energy and intensity of both components. At large wave-vector transfers the scattering is of the form expected from a system of almost free helium atoms. Measurements of the temperature dependence of the results at the smallest and largest wave vectors have been made. In the former case they show well-defined excitations above the λ point which are better defined for large wave vectors, while in the latter case they can be interpreted as giving evidence for the macroscopic occupation of the zero-momentum state. The results are compared with the available theoretical predictions.
Meaning of Kato's Formulas for Upper and Lower Bounds to Eigenvalues of Hermitian Operators
Authors: Hayes Dallas T.
Published: April 2011

Using an independent derivation by Kohn, the full meaning of Kato's formulas for upper and lower bounds to eigenvalues of a Hermitian operator is shown. These bounds are the best possible when the only information available on a particular eigenvalue problem is a suitable trial function and an estimate of the neighboring eigenvalues to the one in question. This was asserted by Kato but not proved. A comparison is made of Kato's bounds with those derived in papers by Stevenson and Crawford and by Cohen and Feldmann. Under the conditions which result in Kato's bounds it is shown that the Stevenson–Crawford and Cohen–Feldmann bounds reduce to those of Kato. When more information is available these bounds are an improvement upon Kato's. This makes more precise the recent work of Walmsley and Cohen–Feldmann, whose results appear to prove in general the greater accuracy of the Stevenson–Crawford and Cohen–Feldmann bounds over those of Kato. A general discussion of all three sets of bounds is given in terms of the parameter λ appearing in the Stevenson–Crawford formulation.
Preliminary Measurements of a Transversely Excited Atmospheric Pressure CO2 Laser
Authors: Fortin R.
Published: April 2011

The design parameters of a transversely excited atmospheric pressure CO2 laser using 1000 Ω. ballast resistors are determined from a series of energy measurements. Peak powers of the order of 1 MW/cm2 at the output window are achieved while the efficiency ranges from 3 to 5% (± 0.3). Improvements based on geometrical and electrical considerations are also suggested.
Longitudinal Ultrasonic Attenuation in Tantalum at Frequencies up to 1 GHz
Authors: Perz J. M. , Roger W. A.
Published: April 2011

The attenuation due to interaction with conduction electrons of longitudinal sound propagating along [110] in a Ta crystal of resistance ratio 390 has been measured over the frequency range 0.46 to 1.0 GHz. The product of the wave vector q and the electronic mean free path l determined from the frequency dependence of the normal state attenuation ranges over 1.8 < ql < 3.8. The attenuation in the superconducting state in the absence of a magnetic field fits the BCS expression for 1.2 < T < Tc = 4.46 K with 2Δ(0) = 3.62 ± 0.06 kTc. The ultrasonic waves have been generated by thin film CdS transducers, and the conversion efficiency has been found to vary inversely with the active area of the transducer.
The 4875 Å Band System of cis Glyoxal
Authors: Currie G. N. , Ramsay D. A.
Published: April 2011

The 4875 Å band of glyoxal has been photographed in absorption under high resolution and a rotational analysis carried out. The band is of type C and the principal molecular constants are: A′ = 0.9069 cm−1, B′ = 0.1983 cm−1, C′ = 0.1627 cm−1, A″ = 0.8910 cm−1, B″ = 0.2066 cm−1, C″ = 0.1681 cm−1, v0 = 20 507.57 cm−1. The A-rotational constants are smaller by a factor of ~2 than the constants found earlier for trans glyoxal. The new results are consistent with the assignment of the band to an allowed 1B1–1A1 (π*–n) transition of cis glyoxal. Temperature studies indicate that the cis isomer lies 1125 ± 100 cm−1 above the trans isomer. This is the first time that cis glyoxal has been detected experimentally.
The 4550 Å Band System of Glyoxal. III. Vibration-Rotational Analyses for 11 Bands of C2D2O2
Authors: Agar D. M. , Bair E. J. , Birss F. W. , Borrell P. , Chen P. C. , Currie G. N. , McHugh A. J. , Orr B. J. , Ramsay D. A. , Roncin J-Y.
Published: April 2011

Rotational analyses have been carried out for 11 bands of the 1Au–1Ag (π*–n) transition of glyoxal-d2 in absorption. Approximately 13 000 lines have been assigned, and rotational and vibrational constants determined by computer methods. The following vibrational frequencies have been determined: ν2′ = 1394.42 cm−1, ν4′ = 866.52 cm−1, ν5′ = 499.04 cm−1, ν7′ = 217.36 cm−1, ν5″ = 537.29 cm−1, and ν7″ = 117.98 cm−1. The bands are relatively free from perturbations with the exception of a Coriolis interaction involving the torsional vibration ν7(au) and the C—C=O bending vibration ν12(bu).
Pressure Narrowing of the Rotational Lines of the Fundamental Infrared Band of H2 in Collision-Induced Absorption
Authors: Remigis J. De , Mactaggart J. W. , Welsh H. L.
Published: April 2011

The enhancement by argon of the pressure-induced fundamental infrared absorption band of hydrogen is studied for Ar densities in the range 8–820 amagat at 152 K. The half-width, Δv1/2, of the quadrupole-induced S1(1) transition remains constant at 55 cm−1 up to ~300 amagat and then decreases to 25 cm−1 at the highest density. In the higher density range Δv1/2 varies inversely as the density. The S1(1) line of H2 in liquid H2–Ar solutions shows a similar pressure narrowing for Ar densities in the range 640–833 amagat at 115 K.
Rotational Analysis of the A–X System of the SiCl Molecule
Authors: Singhal S. R. , Verma R. D.
Published: April 2011

The A–X system of the SiCl molecule in the region 4500–6400 Å has been excited by an r.f. discharge through a mixture of argon and a trace of SiCl4 vapor, flowing through a quartz tube. Several red degraded and double headed bands with ν′ = 0, 1, 2, and 3 have been observed and the rotational structure of the 0-5, 0-6, 0-7, 0-8, 0-9, 0-10, 1-9, and 1-10 bands has been analyzed. The analysis shows that the bands arise from a 2Σ–2Π transition, 2Π being the ground state of the molecule. The molecular constants have been determined for both the electronic states. The spin coupling constant, Aν, of the X2Π vibrational levels has been found to follow an equation[Formula: see text]
Computation of the Composition of a Highly Ionized Plasma in Thermodynamic Equilibrium
Authors: Gautam M. S. , Anandaram M. N.
Published: April 2011

A computer program is described for computing the composition of highly ionized plasmas using the Saha equations. The computations were carried out on an IBM-1130. Suppressed ionization potential, total number density of the ions, and partition functions for ion species are calculated. These calculations are used to obtain an iterative solution of seven Saha equations to evaluate the percentage composition of the various species of the plasma. Calculations are reported for oxygen between 10 000 and 80 000 K and all species up to OVIII are considered to be present in the plasma.
Scattering of Two Quasi-Particles
Authors: Razavy M. , Binder M.
Published: April 2011

For a system of many bosons, quasi-particles are defined as simple excitations having energies equal to those predicted by the Bogoliubov and Valatin–Butler theories. Scattering between these elementary excitations is caused by the residual interaction. This results in a change in the energies of quasi-particles, and a finite lifetime for the excitations. The force between two quasi-particles is determined in terms of the boson–boson potential, and the distribution function for different excitations. Perturbed single particle energies are also calculated within the framework of the reaction matrix.
Measurement of the L/K Electron Capture Ratio in the Decay of 159Dy
Authors: Leiper W. , Jolly O. P.
Published: April 2011

NaI(Tl) crystals containing DyCl3 were used to measure the L/K electron capture ratio in the decay of 159Dy to the ground state of 159Tb. The experimental result was 0.198 ± 0.009. Agreement with theory is obtained if an exchange correction of 1.062 ± 0.046 is used. Bahcall's calculated value for the exchange correction is 1.046.
Spin–Parity Combinations in 22Ne
Authors: Ollerhead R. W. , Allen G. F. R. , Baxter A. M. , Gillespie B. W. J. , Kuehner J. A.
Published: April 2011

Detection of inelastically scattered alpha particles near 180° from the reaction 22Ne(α,α′)22Ne has been used to identify natural parity levels in 22Ne. Energy spectra were recorded for ten incident energies from 16.5–21.0 MeV in steps of 500 keV. Levels at 4.46, 5.52, and 5.92 MeV have been identified as having natural parity, leading to definite assignments of 2+, 4+, and 2+ respectively. Levels at 5.14 and 5.64 MeV have been identified as having unnatural parity, implying assignments of 2− and 3+ respectively. Tentative assignments are suggested for other levels, and the implications of the present assignments with regard to the identification of band structure in 22Ne are discussed.
Crystal Dynamics and Electronic Specific Heats of Palladium and Copper
Authors: Miiller A. P. , Brockhouse B. N.
Published: April 2011

Using inelastic neutron scattering, the frequency – wave vector dispersion relations for the lattice vibrations in a single crystal of palladium have been determined at 120, 296, 673, and 853 °K. Analyses of the results have given force-constant models from which frequency distributions have been computed. First-neighbor interactions are dominant, but weaker interactions also exist, extending beyond sixth-nearest neighbors. The total lattice specific heat (harmonic plus anharmonic) at constant pressure has been calculated, using the frequency distribution at 296 °K and the shifts in the frequencies with changing temperature. Similar calculations were also carried out for copper, using the room temperature distribution reported by Svensson et al.; the temperature dependence of the frequencies was established by carrying out measurements along major symmetry directions of Cu at 296, 473, and 673 °K. The electronic specific heats of Cu and Pd have been calculated at temperatures between 0 and 900 °K. The electronic specific heat of Cu agrees well enough with the linear relation Ce = γT for T < 700 °K. For Pd, Ce is anomalously high at low temperatures, in agreement with experiments at helium temperature, but tends to saturate for temperatures > 200 °K.
Remarks on Gupta's Quantization of the Weak Gravitational Field
Authors: Peet F. G.
Published: April 2011

The two quantum theories developed by Gupta for the weak gravitational field are reviewed. A third formalism is given in which it is assumed that there are only ten field variables. A difficulty is encountered when one attempts to construct graviton number operators. A contact transformation of the field variables is used to resolve the difficulty. The expressions obtained for the graviton propagator and the energy, momentum, and spin of the gravitons agree with the results of Gupta.
Noise Spectrum Measurements from 10 Hz to 1 MHz using a Tunable Switching Radiometer. I. Instrumentation
Authors: Buckmaster H. A. , Rathie R. S.
Published: April 2011

The first application of a switching (Dicke) radiometer to high-precision, noise spectrum measurements from 10 Hz to 1 MHz is described. The solution of the instrumentation problems unique to this frequency range are discussed in detail. The advantage of this radiometer is that it can be employed in a null mode so that it is direct reading and the measurement precision at all frequencies is limited fundamentally by the bandwidth and averaging time or by the calibration of the reference noise source and its attenuator.
Proton Rotating Frame Relaxation in Lithium Hydrazinium Sulfate, Li(N2H5)SO4
Authors: Knispel R. R. , Petch H. E.
Published: April 2011

The temperature dependence of the rotating frame relaxation time T1ρ for protons in powdered lithium hydrazinium sulfate, Li(N2H5)SO4, has been determined from 140 to 495 °K. These measurements indicate that the –NH2 part of the N2H5+ ion executes 180° flips about the bisectrix of the H–N–H angle with activation energy of 10.7 ± 0.5 kcal/mole. Evidence for motion of the entire N2H5+ ion with activation energy of 17.4 ± 1.1 kcal/mole was also obtained. Separate reorientation and diffusion motions of the N2H5+ ion could not be distinguished, although evidence that the N2H5+ motion detected in the T1ρ measurements includes diffusion is obtained by comparing the T1ρ results with the temperature dependence of the proton second moment.
Minimal Set of Independent Recursion Relations for SU(2) Clebsch–Gordan Coefficients
Authors: Bose A. K. , Patera J.
Published: April 2011

It is shown that there are only two independent recursion relations between SU(2) Clebsch–Gordan coefficients from which all known recursion relations can be obtained.
Direct Interaction Theory of Reactive Molecular Collisions: K + Br2 System
Authors: Eu Byung Chan , Huntington John H. , Ross John
Published: April 2011

Reaction cross sections and internal energy distributions are calculated quantum mechanically for the K + Br2 system. The formulation is based on some essential ideas in the Butler theory of the nuclear stripping reactions and results provide a qualitative agreement with experiment on the system.
Range and Range Straggling of 97 keV 224Ra Particles in Gases
Authors: Leon J. , Steiger-Shafrir N. H.
Published: April 2011

High precision range and straggling measurements of 96.5 keV224Ra α-disintegration recoil particles in various gaseous media are described. Special emphasis is placed on the development of a uniform and non-degrading recoil source in order to insure accurate range determination and to prevent broadening of the straggling results by the source. Excellent symmetry for the range distribution curves for all, even the heavy gases, was obtained. The performance of the measurements in gases, where successive collisions can be considered as uncorrelated, enabled a detailed comparison with theoretical treatments of the nuclear stopping mechanism, dominating in this energy region. The results obtained were compared with the Lindhard theory and show good agreement, especially for the medium mass gases.
Generalizations of the Jost–Pais Theorem for Nonlocal Potentials
Authors: Singh Yogeshwar , Warke C. S.
Published: April 2011

We derive general expressions for the Jost function of a nonlocal central potential in any angular momentum state, and generalize these results when there is a tensor component in the nonlocal potential. These results relate the Jost function to the Fredholm determinants and are generalizations of the Jost–Pais theorem for the corresponding local case.
Temperature Differences and Mutual Friction in He II Near Tλ
Authors: Crooks Michael J. , Johnson David L.
Published: April 2011

An experiment has been performed to measure the temperatures at the ends of a cylindrical channel containing He II in the presence of a heat flux through the channel, near the lambda transition. Two channels of cross sections 1.1 mm2 and 2.2 mm2 were used and average temperatures ranged from within 1.0 × 10−2 K of Tλ. to within 3 × 10−5 K of Tλ. The results are fitted to a generalized Gorter–Mellink mutual friction expression of the form[Formula: see text]
Low-Lying Levels of 58Co
Authors: Robertson R. G. H. , Summers-Gill R. G.
Published: April 2011

The odd–odd nucleus 58Co has been investigated experimentally by the 59Co(d,t)58Co and the 55Mn(α,nγ)58Co reactions. In the pickup studies deuteron energies of 15 and 16.5 MeV were used and levels at 0, 25, 52, 112, 365, 375, 456, 888, 1043, and 1078 keV were observed. DWBA analysis showed mixed ln = 1 and 3 transfers for all levels except the last named, which is pure ln = 3. High resolution gamma–gamma coincidence work using the (α,nγ) reaction has revealed the decay properties of a large number of levels up to 1.5 MeV, including all those seen in (d,t), and has allowed tentative spin assignments for a comparison with the theoretical calculations of Vervier. Qualitatively the agreement is good.
Expansion of a Focused Laser Beam in the Turbulent Atmosphere
Authors: Varvatsis A. D. , Sancer M. I.
Published: April 2011

This work examines the expansion of a focused laser beam in the turbulent atmosphere. The formulation is based on Green's theorem and the valid assumption that the turbulent atmosphere is a forward-scatter medium for wavelengths of interest (0.6 μ < λ < 11 μ). The main results are: (1) the spot size at the free-space focal plane in the presence of turbulence is independent of the aperture radius, and is only weakly dependent on the wavelength, (2) the focal plane can be significantly shifted for small aperture radii, short wavelengths, and long free-space focal lengths, (3) the effect of the atmosphere is pronounced only close to the free-space focus and very far away, and (4) the turbulent atmosphere has a stronger effect on weakly focused beams rather than strongly focused beams, except very close to the free-space focus, where the effect is more pronounced for strongly focused beams.
Potential-Energy Function for Diatomic Molecules
Authors: Tietz T.
Published: April 2011

The purpose of this paper is to give a simple expression for the potential-energy function for diatomic molecules for which one can solve the Schrödinger equation exactly for both discrete and continuous energy parameters E. The analytic expression for this potential curve is illustrated numerically for several diatomic molecules.
Electroreflectance Spectra of AlxGa1−xAs Alloys
Authors: Berolo Orazio , Woolley John C.
Published: April 2011

Room temperature electroreflectance measurements have been made on samples of AlxGa1−xAs alloys, grown by liquid epitaxy. The variation of the different band transition energies, E0, E1, E2, etc. has been determined as a function of composition x. For each transition energy, the data have been fitted to the relation E = a + bx + cx2 and hence the bowing parameter c determined. These experimental values of c are compared with the predicted values of Van Vechten.
Studies of Radio-Wave Absorption Features at a Subauroral Latitude
Authors: Abdu M. A. , Vogan E. L.
Published: April 2011

Cosmic noise absorption measurements at 30 MHz were made simultaneously on two antennas having different beam widths at London, Ontario(53 °N geomagnetic, L = 3.1), a subauroral zone station. The data show that absorption is caused by regions of ionization which exhibit marked spatial non-uniformity within the antenna beams, and which have horizontal extensions limited more toward the south than toward the north of the station. The measurements also indicate the presence of auroral ionization at all times of the day over London.
Electric Displacement Gradients in the Elastic Dielectric
Authors: Huang C. C. , Grindlay J.
Published: April 2011

A variational principle is used to derive a nonlinear theory of the static elastic and dielectric response of an insulator whose energy density is a function of the deformation gradients, the electric displacement components, and the electric displacement gradients. The linearized or small field version of this theory differs from Mindlin's theory of the elastic dielectric with polarization gradient arguments in the energy density. From an application of the linear theory to the determination of the response of a particular system with non-piezoelectric cubic material symmetry, it is concluded that to satisfy all the boundary conditions there can be no explicit displacement gradient dependence in the small field energy density representation. An analogous result holds for Mindlin's theory.We also examine three microscopic model calculations, by Ginzburg, Mindlin, and Askar et al., and we conclude that in each case the effect obtained can be attributed equally well to the presence of arguments other than the polarization gradient. Ginzburg's model is shown to have an energy density with arguments which are the polarization components and the gradients of polarization gradients.
Analysis of the Excitation of the Earth–Ionosphere Waveguide by a Satellite-Borne Antenna. II
Authors: Einaudi F. , Wait J. R.
Published: April 2011

The analytical expressions for the fields at the earth surface due to a satellite-borne horizontal dipole are derived for an idealized model in which the Earth's magnetic field is vertical and the medium is divided into plane, parallel slabs. Although nonlinear phenomena in the neighborhood of the antenna are not analyzed, the problem is circumvented by defining an equivalent infinitesimal dipole whose external fields are the same as those of the actual antenna. Finally, a numerical example is given in which the fields of such a horizontal dipole are compared with those of a vertical dipole operating in the same conditions.
Elastic Scattering of Slow Electrons by Lithium Atoms in the Polarized-Orbital Approximation
Authors: Dai Bui Tien , Stauffer A. D.
Published: April 2011

We have calculated the low energy elastic cross section for electrons incident on lithium atoms via the polarized-orbital method proposed by Temkin. The only further approximations made are the exclusion of core polarization and the use of frozen core Hartree–Fock wave functions. Quite good agreement with previous close-coupling calculations are obtained in the energy range 0.5–3 eV. Surprisingly, the threshold resonance behavior predicted by the close-coupling results is obtained when exchange is neglected, but not when the full polarized-orbital method is used.
Rotational Excitation in Li+–N2 Collisions
Authors: Lowe R. P. , Ferguson H. I. S.
Published: April 2011

The population distribution in the rotational levels of the B2Σu+ state of N2+ produced in Li+–N2 collisions has been measured for incident Li+ energies in the range 3 to 10 keV. Boltzmann distributions were found at all energies at rotational temperatures decreasing from 2500 °K for 3 keV excitation to 960 °K for 10 keV. This variation is shown to be consistent with a simple model of the conservation of angular momentum in the collision.
An Action-at-a-Distance Theory of Gravitation. II. Tensor Interactions
Authors: Volkov A. B.
Published: April 2011

A previous paper showed that the classic tests of the general theory of relativity can all be explained in terms of a special relativistic action-at-a-distance theory involving an appropriate mixture of a scalar and vector interaction. The theory has been generalized to tensor interactions of all orders. The demands of special relativity and the perihelion advance of Mercury lead to a unique specification of the scalar interaction strength, but since the limit for all other tensors is the same for the perihelion advance (one sixth the general relativity result) only the sum of the interaction strengths can be determined for these tensors. Some possible physical consequences are discussed.
Isomeric State of 97Rh
Authors: Lopez A. M. , Prestwich W. V. , Arad B.
Published: April 2011

Radioactive 97Rh was produced via the 96Ru(p,γ)97Rh reaction. The two most intense lines in the γ-ray spectrum of 97Rh, at 190 and 421 keV, were observed to decay with half-lives of 40 ± 2 and 30 ± 2 min respectively. This result is interpreted as evidence for a 30 min isomeric state in 97Rh. The interpretation is further supported by the observation of the 19 keV Rh Kα X ray. With this interpretation it is possible to resolve a discrepancy in the observations of previous investigators as regards the relative intensity of the 190 and 421 keV transitions.
On Spherical Hartree–Fock Calculations with Sussex Interaction
Authors: Kakkar I. , Waghmare Y. R.
Published: April 2011

Spherical Hartree–Fock calculations for 4He, 12C, and 16O nuclei have been carried out with Sussex relative matrix elements of Elliott et al. It is observed that the calculated binding energies for all these nuclei are considerably smaller than the experimental values. However, the Sussex matrix elements give better results for the binding energies of these nuclei compared with the truncated results of other realistic interactions in most of the cases. The rest of the calculated properties are in fair agreement with experiments.
Nouvelle Méthode de Mesure de la Cohérence Spatiale en Lumière Pseudo-Thermique par Comptage des Photoélectrons
Authors: Delisle Claude , Bures Jacques
Published: April 2011

The light from a pseudothermal source is simultaneously detected in two points of the observation plane with a single photodetector. The degree of spatial coherence between the two points is determined from a comparison between one of the moments of the theoretical probability density P(i) of the light intensity at the photocathode and the corresponding moment of the experimental distribution of the photoelectrons. The moments of the probability density P(i) are derived from an exact theory which takes into account the degree of spatial coherence between the two points of the observation plane.
Low Attenuation Shock Tube: Driving Mechanism and Diaphragm Characteristics
Authors: Curzon F. L. , Phillips M. G. R.
Published: April 2011

The properties of an electric shock tube fitted with a diaphragm are examined. The diaphragm opening process and its effect on the motion of the shock wave are studied. A simple model to account for the diaphragm opening time is given and critical comparisons of theory and results with other work are made.The model works well both for shock tubes employing room temperature driver gas and also for those using heated driver gas. Furthermore, there is strong evidence that the diaphragm opening process is responsible for the accelerating phase of the shock wave motion in both types of shock tube.
Compressibility under Deformation of the Nuclear Hartree–Fock Field
Authors: Castel B. , Svenne J. P.
Published: April 2011

The 'compressibility under deformation' effect observed in isotopic shift experiments is analyzed in a deformed Hartree–Fock model. The empirical parameter ξ deduced previously from experiment is found to be consistent with the calculated estimate using a realistic interaction in four f–p shell nuclei.
Neutron Yield from Protons and Deuterons of Momenta between 0.85 and 1.7 GeV/c Totally Absorbed in Lead
Authors: West D. , Wood E.
Published: April 2011

Neutron yields from protons and deuterons accelerated by the Birmingham synchrotron were measured at a series of momenta up to 1.7 GeV/c in a lead target 10 cm diameter and 60 cm long. The observed yield from deuterons is greater than that expected from two protons each having one half of the deuteron energy but is close to that which can be deduced from the measured proton yield on the hypothesis that stripping reactions are the predominant processes involved in the first interaction.
Elastic Scattering of Electrons from Argon-40
Authors: Groh J. L. , Singhal R. P. , Caplan H. S.
Published: April 2011

The r.m.s. charge radius of Argon-40 was measured by elastic electron scattering in the momentum transfer range 0.5 < q < 0.85 fm−1. The result obtained using a phase shift code and assuming a Fermi distribution was 3.473 ± 0.045 fm.
Sign of 'δ', the Amplitude Mixing Ratio of Gamma Transitions, and Gamma–Gamma–Gamma Angular Correlation Studies in 160Dy
Authors: Pande U. S. , Singh B. P.
Published: April 2011

The importance of gamma–gamma–gamma angular correlation in order to study the absolute sign of 'δ', the amplitude mixing ratio of gamma transitions, independent of phase convention is given. A study of the triple gamma-rays cascade of 298 keV → 879 keV → 87 keV in 160Dy from the decay of 160Tb has been done.
Influence of Shear Stress on Screw Dislocations in a Model Sodium Lattice
Authors: Basinski Z. S. , Duesbery M. S. , Taylor Roger
Published: April 2011

The behavior of the screw dislocation core in the presence of an external shear stress has been examined for the body-centered cubic and hexagonal close-packed phases of a model sodium lattice, using an effective ion–ion potential calculated from first principles. The Peierls stress for screw dislocations in the b.c.c. lattice at 0 °K is dependent on the orientation of the applied shear stress, and has a minimum value of 0.0105G, where G is the shear modulus, for slip in the twinning direction on {112} planes. The Peierls stress in the h.c.p. lattice is at least 25 times smaller. Dislocation movement in the model b.c.c. lattice takes place by unit translations on {110} planes, with the selection rule that no two consecutive translations can take place on the same slip plane.
Power Spectral Analyses of Auroral Light and X-Ray Pulsations
Authors: Scourfield M. W. J. , Parsons N. R.
Published: April 2011

Higher frequency components in auroral light pulsations are shown to be considerably damped relative to similar components in associated X-ray pulsations. This effect can be explained in terms of velocity dispersion of electrons of different energies whose flux in the loss cone is modulated simultaneously in a localized region some 105 km out along auroral zone field lines. An alternative explanation is suggested which involves an energy-selective modulation mechanism which could be acting quite close to the ionosphere.
Electron Resonance of Vibrationally Excited OH Radicals
Authors: Lee K. P. , Tam W. G. , Larouche R. , Woonton G. A.
Published: April 2011

Hydroxyl radicals in the vibrational levels ν = 1, 2, 3, and 4 of 2Π3/2, J = 3/2 state were observed by means of electron resonance at a frequency of 8.9 GHz. The lambda doubling frequencies, the g factors, and the hyperfine interaction constants are obtained and they are in agreement with the results of another recent experiment.
Spin and Magnetic Moment of 151Sm
Authors: Robertson R. G. H. , Choh Sung Ho , Summers-Gill R. G. , Stager C. V.
Published: April 2011

The spin and magnetic moment of 87 y 151Sm have been measured by electron paramagnetic resonance (EPR);I = 5/2 and [Formula: see text] nuclear magnetons.
Optical Study of Silicon Doubly Doped with Boron and Indium Acceptors
Authors: Bhatia K. L.
Published: April 2011

The external and internal absorption spectra of silicon doubly doped with boron and indium acceptors is studied. The observed broadening of the boron absorption lines in Si(B, In) is explained by neutral impurity scattering. The presence of indium in the Si(B, In) crystal lattice modifies the valence band Bloch states and hence the configuration interaction between the internal acceptor states and the degenerate P3/2 valence band Bloch states. This modification is found responsible for the observed features of the boron 2p′ internal line in Si(B, In).
Two New Subsystems of PtH in the Region 3500–5800 Å
Authors: Kaving Birgitta , Scullman Rosemary
Published: April 2011

The spectrum of PtH has been investigated in emission. Besides the A2Δ5/2–X2Δ5/2 and the B2Δ5/2–X2Δ5/2 subsystems, obtained earlier in absorption, a 2Δ3/2–X2Δ3/2 and a 2Φ7/2–X2Δ5/2 subsystem have been detected. These new subsystems have been rotationally and vibrationally analyzed. The term values have been calculated. The spin–orbit coupling constants (A0 ≈ −615 cm−1) for the X2Δ state have been computed by fitting an energy formula to the term values.
Effect of Temperature on the Angular Distribution of Backscattered Protons in Gold and Zinc
Authors: Howe L. M. , Schmid S.
Published: April 2011

The influence of thermal vibrations on the angular distribution of the yield of backscattered protons (incident energy 100 keV) has been investigated for various axial and planar dips in gold and zinc. The angular distributions were markedly influenced by the crystal temperature and by the depth beneath the crystal surface from which the protons were scattered. In gold, data were obtained over the range 77–873 °K and the angular width ψ of the distributions was observed to vary exponentially with the root-mean-square vibrational amplitude ρ regardless of the scattering depth. Also in gold, the minimum yield χmin was found to be proportional to ρ2 for those protons scattered from near the crystal surface but a deviation from this behavior was noted as the depth of scattering increased. In zinc, data were obtained at 77 and 295 °K and the magnitude of the observed temperature effect was at least as large as in gold when compared on the basis of root-mean-square vibrational amplitudes. The experimental results are compared with analytical and computer results of other investigators.
Some Characteristics of Irregular Micropulsations Pi2 at High Latitude Stations
Authors: Gupta Jagdish C. , Stening Robert J.
Published: April 2011

Pi2 micropulsations were studied for the period July 12 to August 16, 1968, from four observatories at different latitudes in Canada. Maximum occurrence was near midnight with a preference for 5–6 h UT at all longitudes studied. The relationship of Pi2 occurrence to magnetic bays and to Kp is examined. The correlation of Pi amplitudes and periods with Kp and other parameters reveals a different pattern for lower latitude stations (Ottawa and Meanook) compared with Baker Lake (73.9 °N). These results are interpreted as evidence for two different types of Pi in the different latitude regions, the lower latitude Pi being associated with hydromagnetic waves on the plasmapause. In studies of simultaneous Pi events at the four stations, the maximum amplitude occurred most frequently at Meanook. Polarization of such events was found to be different at different stations and so previously reported patterns of Pi polarization could not be confirmed.
Cyclotron Masses in Copper
Authors: Coleridge P. T. , Watts B. R.
Published: April 2011

Using the de Haas – van Alphen effect, measurements have been made in pure copper of the cyclotron mass values at the symmetry directions. The results are in general some 1.3% lower than earlier values and are in excellent agreement with the measured electronic specific heat.
Investigation of the Rotary Lattice Mode in R2PtCl6 Compounds. I. From Measurements of the 35Cl Nuclear Quadrupole Resonance Frequency
Authors: Cooke Douglas F. , Armstrong Robin L.
Published: April 2011

Measurements of the temperature and pressure variation of the 35Cl nuclear quadrupole resonance (NQR) frequency in Rb2PtCl6 and Cs2PtCl6 are reported. The resonance frequency is measured at atmospheric pressure for temperatures from 4 to 500 K and at four temperatures between 290 and 380 K for pressures to 5000 kg cm−2. Previously published data for K2PtCl6 are also included in the analysis. Static lattice NQR frequencies are deduced. The differences between the static lattice frequencies are compared with the calculations of Smith and Stoessiger. Thermal averaging of the electric field gradient at a chlorine site is assumed to be dominated by the Q3, Q4, Q5, and Q6 internal modes of the PtCl6 octahedra and by the rotary lattice mode. The rotary mode frequencies are deduced; they are of similar magnitude and increase in the same sequence as the frequencies deduced from infrared and Raman data. An analysis of the pressure dependence of the NQR frequencies leads to pressure coefficients for the rotary mode frequencies. The influence of the cage of R atoms surrounding a PtCl6 octahedron is shown to increase through the series K2PtCl6, Rb2PtCl6, Cs2PtCl6. Finally, a thermodynamic analysis of the NQR data is presented which shows the importance of taking specific volume effects into account.
Measurement of the Critical Temperature in MnCl2∙4H2O, MnBr2∙4H2O, and their Deuterated Modifications
Authors: Turrell B. G. , Yue C. L.
Published: April 2011

We have observed λ-type discontinuities in ∂χ/∂T, χ being the magnetic susceptibility at temperature T, in single crystal specimens of MnCl2∙4H2O and MnCl2∙4D2O and polycrystalline specimens of MnBr2∙4H2O and MnBr2∙4D2O. Assuming this discontinuity occurs at the critical temperature Tc, we measure Tc = 1.611 ± 0.002 K for MnCl2∙4H2O, Tc = 1.545 ± 0.002 K for MnCl2∙4D2O, Tc = 2.117 ± 0.002 K for MnBr2∙4H2O, and Tc = 2.093 ± 0.002 K for MnBr2∙4D2O.
Sheath-Convection Effects with Flush-Mounted Electrostatic Probes
Authors: Clements R. M. , Smy P. R.
Published: April 2011

Theoretical expressions are derived for the ion current to a planar flush-mounted probe which arises from the convection of ions from a moving plasma into the probe sheath. The two situations considered are those where the sheath is either very large or is small compared with the boundary layer. It is found that sheath effects, with an accompanying lack of true current saturation with increasing probe bias, can be expected to intrude when the parameter REα2χ2 > (X/l)1/4. (RE = electric Reynold's number, α = ratio of Debye length to probe length [X], χ = potential of probe normalized with respect to the electron energy, and l = the distance of the probe from the leading edge of the surface into which it is mounted.) For values of REα2χ2(l/X)2 which exceed unity, the formula[Formula: see text](where ne = plasma electron density, u∞ = free stream flow velocity, V = probe bias, μ∞ = free stream ion mobility, e = electronic charge, and ε0 = permittivity of free space) is derived. At lower values of REα2χ2(l/X)2 theoretical considerations which take compression and cooling effects into account show that the above relation should still be approximately correct down to values of [Formula: see text]. The relation shows good agreement with the recent results presented by Scharfman and Bredfeldt under conditions where they report the conventional diffusion theory to be in error by up to one order of magnitude, and moreover to predict an incorrect variation of current with electron density and probe bias.
Contributions of Nonspherical Interactions to the Second Virial Coefficients of H2 and HD Gases
Authors: Rakshit Asit B. , Chowdhury Sucheta
Published: April 2011

The second virial coefficient B(T) of H2 and HD gases, including the quantum corrections, have been evaluated by considering spherical as well as the different nonspherical interactions arising mainly from the permanent and induced electric moments of the molecules. The calculations are valid at intermediate temperatures where the quantum effects are comparatively small. For H2 the present results have been compared with the earlier ones of Wang Chang.
Possible Effects of Proton Tunnelling in Magnetically Ordered Systems
Authors: Pink D. A.
Published: April 2011

The behavior of a magnetically ordered system in which one of the superexchange paths is through a short (~2.5 Å) hydrogen bond has been investigated with particular attention paid to the case of HCrO2. It has been assumed that the exchange integral for this path depends upon the particle (proton or deuteron) position in the bond and that the particle is tunnelling in a symmetric double-minimum potential well. The following quantities have been calculated: (i) the particle tunnelling spectrum (in particular, the infrared spectrum) for (a) general temperatures if particle–particle interactions are ignored and (b) temperatures such that few tunnelling modes are excited when these interactions are taken into account, and (ii) the low-temperature magnon spectrum, magnetization, and specific heat when particle–particle interactions are both ignored and considered. The results are compared with those that are to be expected if the initial assumption about the dependence of the exchange integral is incorrect.
Accurate Numerical Hartree–Fock Self-Consistent-Field Wave Functions for Rare-Earth Ions having 4fN6s Configuration
Authors: Saxena K. M. S. , Malli Gulzari
Published: April 2011

Accurate numerical Hartree–Fock (HF) self-consistent-field (SCF) wave functions have been obtained for Ce+(4f26s)4H, Pr+(4f36s)5I, Nd+(4f46s)6I, Pm+(4f56s)7H, Sm+(4f66s)8F, Eu+(4f76s)9S, Gd+(4f86s)8F, Tb+(4f96s)7H, Dy+(4f106s)6I, Ho+(4f116s)5I, and Er+(4f126s)4H rare-earth ions. In general, total energy values have an accuracy of seven significant digits. The virial theorem is satisfied to the minimum of six significant digits and the Pnl wave functions are self-consistent to at least five significant figures. Several HF parameters are also evaluated with these wave functions.