bluuebunny/crossref_metadata_2025 huggingface dataset:
CHANNELING IN GOLD
Authors: Whitton J. L.
Published: April 2011

The penetration of radioactive 133Xe and 198Au ions into oriented monocrystals of gold has been measured in the energy range 20 to 80 keV using an electrochemical sectioning technique. Channeling along low index directions was observed to increase in the order [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], in agreement with theory and with the previous experimentally determined order in other f.c.c. lattices such as copper and aluminium. Two distinct differences in the channeling behavior of ions in gold compared to tungsten are noted: (1) a much smaller fraction of the incident ions remains channeled and (2) the maximum range of the channeled ions is much larger than in tungsten. These differences in behavior are ascribed to the increased multiple scattering due to the higher r.m.s. vibrational amplitude and the lower electronic stopping power in gold. "Supertails" (interstitial diffusion processes) have not been observed. Depth distributions of various other ions at a constant velocity show essentially no dependence on mass.
THE QUASI-STATIC FIELD OF AN ELECTRIC DIPOLE EMBEDDED IN A TWO-LAYER CONDUCTING HALF-SPACE
Authors: Weaver J. T.
Published: April 2011

Solutions are derived for the quasi-static electromagnetic field produced by an electric dipole located in the upper layer of a two-layer conducting half-space. Two orientations of the dipole are considered, (i) normal to, and (ii) parallel to the plane surface of the conductor. The well-known solutions for the corresponding fields of a dipole in a uniform conducting half-space emerge as special cases. Numerical calculations of the amplitudes and phases of the field components are made for a dipole situated midway down an upper layer one "skin depth" thick. The results are presented in a dimensionless form and are dependent only on the ratio of the conductivities of the two layers.
EFFECT OF VISCOSITY ON VERTICAL OSCILLATIONS OF AN ISOTHERMAL ATMOSPHERE
Authors: Yanowitch M.
Published: April 2011

The problem considered is that of small amplitude vertical oscillations of a viscous isothermal atmosphere. The viscosity coefficient μ is assumed to be constant. It is shown that in any fixed z interval (z being the vertical coordinate) for frequencies below a critical frequency, the solution approaches (as μ → 0) the solution of the inviscid problem for which the kinetic energy in a column of fluid is finite. For frequencies higher than the critical one, however, viscosity not only damps the motion at large altitudes, but also reflects waves downward. The solution does not go to a Iimit as μ → 0, but the ratio of the amplitudes of the reflected and the incident wave approaches exp(−πβ), where β is the ratio of the vertical scale height to the wavelength. For small β, therefore, the solution of the inviscid problem satisfying the radiation condition is not accurate.
ASYMPTOTIC LARGE-Z ATOMIC OSCILLATOR STRENGTHS
Authors: Cohen M.
Published: April 2011

Two-term asymptotic expansions for the oscillator strengths of a number of important lines of the helium and lithium isoelectronic sequences are presented. The leading term in each expansion is exact, while the second term is obtained by a fit to the accurate f values for Ne+8 and Ne+7 recently published by Wiese, Smith, and Glennon (1966). It is found that these asymptotic expansions also give very accurate f values for many of the lower members of the two sequences.
LANDAU LEVELS IN METALS—A PHYSICAL ANALOGUE
Authors: Taylor P. L.
Published: April 2011

The Schrödinger equation is considered for a simple model of a conduction electron in a uniform magnetic field. It is shown how this equation may be transformed into an approximate description of a different and simpler physical problem, from which the usual semiclassical results may be derived.
CRYSTALLINE FIELD THEORY OF Ni2+ COMPLEXES
Authors: Chatterjee R.
Published: April 2011

The energy levels of the octahedrally and the tetrahedrally coordinated 3d8 Ni2+ complexes have been calculated using the Racah formalism (1942), taking account of both the crystalline electric field and the spin-orbit coupling. The predicted optical absorption spectra are in satisfactory agreement with the observed spectra in the octahedral complexes by Hartmann and Müller (1958) and in the tetrahedral complexes by Cotton et al. (1961). The magnetic susceptibility calculated using these energy levels agrees with the experimental values. It is found that the Racah parameters must be reduced by 55% from the free ion values in order to explain the optical absorption spectra in tetrahedral complexes.
ON A THEORY OF MEASUREMENT OF INCOMPATIBLE OBSERVABLES IN QUANTUM MECHANICS
Authors: Prugovečki Eduard
Published: April 2011

The empirical meaning of the simultaneity of measurement of several observables is carefully analyzed. General criteria sufficient to guarantee the internal consistency of a framework including simultaneous measurements of incompatible observables are put forward. The case is illustrated with the example of simultaneous measurements of position and momenta of particles in quantum mechanics. It is pointed out that, in general, the outcome of measurements of incompatible observables cannot be described statistically by means of the probability measures of mathematical statistics, which have primarily been introduced only with compatible observables in mind. The concept of complex probability measure is put forward. A generalization of the current interpretation of quantum mechanics is proposed that would also include the case of incompatible observables, by taking advantage of the concept of complex probability measure.
THE DETERIORATION DEPTH IN ZnS:Ag UNDER PROLONGED BOMBARDMENT BY HEAVY IONS
Authors: Wijngaarden A. van , Hastings L.
Published: April 2011

Local regions on a ZnS:Ag phosphor sample were bombarded by a large number (~1014 per cm2) of heavy ions. This irradiation damaged the phosphor to various depths which depended on the energy of the deteriorating ions. These depths were determined by measuring the energy loss of energetic hydrogen projectiles as they passed through the damaged phosphor regions. It was found that the deterioration depths increase approximately as the square root of the incident energy and for the heavier projectiles (40Ar and 84Kr) these depths are about an order of magnitude larger than the corresponding ranges predicted by the Lindhard theory. No direct correlation, however, between the deterioration depth and the range of the heavier ions is implied.
ENERGIES AND HALF-LIVES OF ISOMERIC LEVELS IN THE NUCLEI 139Ce, 141Nd, 161Ho, AND 163Ho
Authors: Geiger J. S. , Graham R. L.
Published: April 2011

A search has been made for delayed γ rays with 1 second [Formula: see text] minutes following 10.5-MeV proton bombardment of 18 natural metallic targets. The five activities observed are: (1) 139Ce, Eγ = 754.5 ± 1.3 keV, [Formula: see text] second; (2) 141Nd, Eγ = 756.8 ± 1.3 keV, [Formula: see text] second; (3) 161Ho, Eγ = 211 ± 2 keV, [Formula: see text] second; (4) 163Ho, Eγ = 299 ± 2 keV, [Formula: see text] second; and (5) a γ ray of 122 ± 2 keV, [Formula: see text] second which is tentatively assigned to 179Ta. All transitions have been measured using a Ge(Li) γ-ray detector. The internal conversion electrons of the transitions in 139Ce and 141Nd were also studied using an orange β-ray spectrometer. Rotational transition energies in 158Dy, 164Er, 168Yb, and 174Hf were measured in conjunction with the internal conversion studies and are reported in an Appendix.
STUDIES IN THE DECAY OF THE ACTIVE DEPOSIT OF ACTINIUM: III. LEVELS IN 211Bi AND ITS DAUGHTER PRODUCTS
Authors: Davidson W. F. , Cothern C. R. , Connor R. D.
Published: April 2011

Previous work on the decay of 211Pb has been developed and extended using lithium-drifted germanium detectors and sum–coincidence techniques. A more detailed level scheme for 211Bi has been produced with greater precision in the determination of the energies and intensities of the 16 gamma rays observed.The alpha decays of 211Bi and 211Po have been studied using solid-state detectors with a resolution of 15.5 keV at 6 MeV. The alpha branching of 211Bi to the 350-keV level in 207Tl has been found to be 16.43 ± 0.04% and that of 211Po to the 570-keV level in 207Bi to be 0.50 ± 0.07%. The beta–alpha branching ratio in the decay of 211Bi is 0.274 ± 0.004%. The data enable upper limits to be placed on any other alpha groups in the active deposit in the energy range 3–13 MeV.The gamma-ray spectrum of separated sources of 207Tl has been found to consist of a single transition of energy 898 ± 0.5 keV with an intensity of 0.002 4 ± 0.000 4 photons per 207Tl decay or 0.002 9 ± 0.000 4 photons per 211Pb decay.A decay scheme for the entire active deposit is given.
THE ENERGY LOSS OF HEAVY IONS IN ZnS:Ag IN THE keV ENERGY RANGE
Authors: Hastings L. , Ryall P. R. , Wijngaarden A. van
Published: April 2011

Local spots on the surface of ZnS:Ag phosphor samples were deteriorated by a large number (~5 × 1013 ions per cm2) of low-energy ions. In this manner thin films which did not luminesce under ion bombardment were prepared. These phosphor samples were scanned across energetic ion beams with sufficient energy to traverse the thin phosphor films. By comparing the luminescent response to this ion excitation in the damaged and undamaged portions of the phosphor surface the total average energy losses of 1H, 4He, 14N, 40Ar, and 84Kr, in passing through the films, were determined. It was found that the energy losses for the heavier projectiles, when compared with the energy loss for hydrogen, are appreciably smaller than those predicted by the Lindhard and Scharff theory.
SOME TRANSPORT COEFFICIENTS IN n-TYPE DEGENERATE SEMICONDUCTORS
Authors: Sharma Satish
Published: April 2011

In this paper the author has studied the variation of Lorentz number, Hall coefficient, magnetoresistance, and Hall mobility with impurity parameter. The effect of ionized impurity scattering has also been considered.
A STUDY OF THE GAMMA RADIATION FOLLOWING NEUTRON CAPTURE IN COPPER
Authors: Colenbrander A. H. , Kennett T. J.
Published: April 2011

The neutron capture gamma-ray spectrum for a natural copper target has been investigated using a Ge(Li) spectrometer. A total of 146 gamma rays were observed, of which about half have been isotopically assigned. Assignment was achieved through the use of coincidence measurements and (d, p) results. The neutron separation energies were found to be 7 914(3) and 7 063(3) keV for 64Cu and 66Cu respectively. The 66Cu gamma-ray transition to low-lying states exhibit exceptionally large radiation widths in a manner similar to the corresponding anomaly in 64Cu.
ON THE MEAN CROSS CAPACITANCE BETWEEN PARALLEL PLANES OF A CUBE
Authors: McLane P. J. , Makow D. M.
Published: April 2011

The capacitance between parallel planes of a cube has been calculated. The arithmetic mean of the three values has been found to be less affected by perturbations from symmetry than any single value. The improvement factor is 13.45. The theoretical results have been confirmed experimentally.Using the mean value as the measure of capacitance, less stringent machining tolerances and less precision in assembly are required than when a single value of capacitance is used.
EFFECT OF TEMPERATURE ON THE PENETRATION OF HEAVY keV IONS IN MONOCRYSTALLINE SOLIDS: I. 133Xe IONS IN GOLD
Authors: Channing D. A.
Published: April 2011

The effect of target temperature on the penetration distribution of 40-kev 133Xe+ ions injected into oriented single-crystal gold has been measured from 20 to 295 °K. The penetration was determined by the anodizing–stripping procedure of Whitton and Davies (1964), and the low-temperature irradiations were performed using a special liquid helium cryostat incorporated into the Chalk River isotope separator. The observed influence of temperature is marked. The median range for both [Formula: see text] and [Formula: see text] incidence is a factor of 2 greater at 20 °K than at 295 °K, and the depths beyond which 10−2, 10−3, and 10−4 of the particles travel are, correspondingly, up to a factor of 3 greater at 20 °K. In these two directions, the range of the "perfectly" channeled particle varies with temperature consistently with the exponential dependence predicted by Lehmann and Leibfried (1963). At [Formula: see text] incidence, little channeling appears to occur characteristic of this direction, even at 20 °K; however, a few percent of the ions do have deep penetrations, arising, it is thought, from channeling skew to the [Formula: see text]. Perhaps surprisingly, the [Formula: see text] distribution exhibits a strong temperature dependence, which is suggestive of a lattice effect with higher stopping power than in amorphous material.
OPTICAL PROPERTIES OF THE BETA-PHASE ALLOYS AuZn, GuZn, AND PdIn
Authors: Jan J.-P. , Vishnubhatla S. S.
Published: April 2011

The reflectance of β′-AuZn, β′-CuZn and β′-PdIn (cesium chloride structure) has been measured between 0.5 and 9 eV, and the other optical constants have been calculated by means of the Kramers–Kronig relations. The results can be explained in terms of interband transitions, the most important of which set in at 2.3, 2.4, and 2.3 eV respectively, and of intraband transitions. The possible occurrence of plasma resonances is discussed.
TWO-BAND CONDUCTION IN Pt, W, AND Pb
Authors: Berry R. J.
Published: April 2011

Earlier investigations on Pt, W, and Pb have indicated that the electrical resistivity may often be represented by a two conduction band model with certain temperature-independent parameters. This model is carefully re-examined here, and shown to lead to serious contradictions between experiment and theory. Possible explanations for the failure of this model are discussed briefly. In addition, new analytical relationships are presented which facilitate the calculation of the two-band parameters.
ON DIFFRACTION BY A HALF-PLANE IN AN ARBITRARY ANISOTROPIC MEDIUM
Authors: Hurd R. A.
Published: April 2011

A method of uncoupling simultaneous Wiener–Hopf equations is developed. If the kernel-matrix G of the equations has the form G = Γ1(A + Γ1B), where Γ1, Γ2 are scalars and A and B are polynomial matrices, then the method works if the elements of A and B satisfy a certain equation called the "criterion".The method is applied to the diffraction of an arbitrary plane wave by a conducting half-plane in a medium with arbitrary tensor permittivity. It is found that in certain circumstances, G has the correct form Γ1(A + Γ2B). Application of the criterion then yields in principle a catalogue of solvable problems. In practice a complete listing has not been obtained because of the amount of algebra involved. However, a partial catalogue has been prepared. It includes most of the previously solved problems plus one or two which have not yet been considered. An example is briefly considered.
A METHOD FOR DIGITAL RECORDING FOR MASS SPECTRA
Authors: Weichert D. H. , Russell R. D. , Blenkinsop J.
Published: April 2011

A method has been devised for the digital recording of mass spectra and for the completely automatic reduction of the data by means of an IBM 7040 digital computer. Spectral analysis of the base-line noise served as the basis of a decision to sample at half-second intervals. For a scanning rate of 20 seconds per unit mass separation, which is used for our lead trimethyl measurements, it is found possible and advantageous to filter the data digitally, using a filter with a half-power point at 0.15 cycles per second which is phase distortionless. The resulting record has a very much higher signal-to-noise ratio than is available directly from the mass spectrometer.After filtering the data, the computer proceeds to note the locations and amplitudes of maxima and minima in the spectra. It identifies the peaks and selects those that are required for computation. Tails due to pressure scattering are computed and corrections for such tails are applied to all peak heights. Decisions are made for each peak to determine whether maximum peak height or the height at the center of the area should be used, since it is advantageous to use different criteria for different peaks in the spectrum. From these data the spectrum is deconvolved and the isotope ratios for the lead samples are computed.While the procedures adopted are of general interest and are not restricted to any particular measuring system, details are given of the system applied in our laboratory and of the tape format used.
ELECTRON SPECTRA IN THE DECAY OF THALLIUM-204
Authors: Park J. J. H. , Christmas P.
Published: April 2011

The continuous beta spectrum and the K Auger-line spectrum in the decay of 204Tl were investigated using a high-resolution, iron-free, [Formula: see text] double-focusing spectrometer. Instrumental distortion of the beta spectrum was shown to be very small and a linear Fermi–Kurie plot was obtained using the generalized unique first forbidden shape factor bq2 + λ2p2, with b = 1.161 ± 0.005. The end-point energy was determined to be (763.24 ± 0.31) keV. Measured values for the energies and relative intensities of the K Auger lines were in broad agreement both with theory and with previous experimental work. The K fluorescence yield was estimated to be 0.97 ± 0.017.
EFFECT OF LATTICE DISTORTION ON THE DEBYE–WALLER FACTOR: I. EXTENDED INTERNAL DEFECTS
Authors: Vail J.
Published: April 2011

A model is introduced in which a Mössbauer atom in an extended internal defect is replaced by a point defect in a perfect lattice, with coupling equal to that in the extended defect. Lattice distortions are considered which are typical for extended defects, with 5 and 10% dilatation and compression, effective coupling constants in nearest-neighbor harmonic approximation are estimated for these cases for a monatomic cubic crystal with Morse potential interaction, and Visscher's data are then used to estimate the fractional change in the Debye–Waller factor, e−2W. Decreases of 14 and 38% are found in e−2W for 5 and 10%, respectively, of lattice dilatation in extended defects, using parameters that are typical of monatomic metals.
EFFECT OF LATTICE DISTORTION ON THE DEBYE–WALLER FACTOR: II. CRYSTAL SURFACES
Authors: Vail J.
Published: April 2011

The lattice distortion which occurs at the surface of a monatomic metal is investigated by considering a simple cubic model based on a Morse potential interaction between pairs of atoms. Effective nearest-neighbor harmonic coupling constants are estimated for the following cases: (a) an atom in an infinite monatomic cubic crystal; (b) an atom in the surface layer of a semi-infinite monatomic cubic crystal, taking account of lattice distortion, and considering vibrations both parallel and perpendicular to the surface; and (c) an atom cn the surface, vibrating perpendicular to the surface. From these results the relative magnitudes of the Debye–Waller factor are estimated for the various cases. It is found that this model, in contrast to purely harmonic-force models, has the Debye–Waller factor for vibrations parallel to the surface greater than the bulk value. Also, comparison with the results of other models suggests that surface lattice distortion reduces the Debye–Waller factor from the bulk value by about as much as does the creation of a surface itself, ignoring the attendant lattice distortion.
HYDROMAGNETIC KELVIN INSTABILITY IN THE PRESENCE OF NEUTRAL PARTICLES
Authors: Rao S. S. , Kalra G. L.
Published: April 2011

The stability of a tangential discontinuity in velocity in a plasma mixed with cold neutral particles is investigated in the presence of a uniform magnetic field. It is found that the effect of collisions between the plasma and the neutral particles is stabilizing or destabilizing according as ν, the collision frequency, is less than or greater than the parameter kc, where k is the wave number of the perturbation and c is the speed of sound for the plasma.
HIGH-PRECISION INDIUM RESISTANCE THERMOMETERS
Authors: Kos J. F. , Drolet M. , Lamarche J. L. G.
Published: April 2011

An account is given of the design, construction, calibration, and reproducibility of two types of indium thermometers. The type B thermometer was found to be reproducible to better than 0.01 °K between 4.2 °K and room temperature. However, thermometers employing indium from the same spool and constructed in the same way do not show the same Z function; consequently each thermometer must be calibrated over the range in which it is to be used.
ABSORPTION-LINE BROADENING IN BORON-DOPED SILICON
Authors: White J. J.
Published: April 2011

In boron-doped silicon, the excitation of bound holes from the acceptor ground state to the excited states leads to an infrared absorption-line spectrum. In a recent half-width study of the boron absorption lines, Colbow (1963) separated the various line-broadening contributions for the first time. Part of Colbow's half-widths is now found to be due to external strains introduced by the sample mounting. New half-width measurements of "strain-free" mounted boron-doped silicon are presented, Colbow's work is corrected, and additional information regarding the various broadening contributions is given.
STRUCTURE OF THE BAND SPECTRUM OF THE CuBr MOLECULE: I. ROTATIONAL STRUCTURE OF THE C SYSTEM OF 63Cu81Br
Authors: Rao P. Ramakoteswara , Apparao K. V. S. R.
Published: April 2011

The C band system of 63Cu81Br, lying in the region 3 900–4 600 Å, has been photographed in emission under high resolution and rotational analysis of the (2–0), (1–0), (0–0), (0–1), (0–2), and (1–3) bands carried out. The system is shown to involve a 1Σ(C1Σ)–1Σ(X1Σ) transition. The molecular constants of 63Cu81Br obtained from this fine-structure analysis are as follows:[Formula: see text]
VIBRATING NEUTRON STARS
Authors: Hansen Carl J. , Tsuruta Sachiko
Published: April 2011

The time variation of some interesting properties of vibrating neutron stars is considered. The models used are based on two nuclear potentials that cover a large spread of possibilities. The modified URCA neutrino process has been assumed to be the major damping mechanism. The calculations are performed both for the case when the vibration energy is partially converted into heat through the URCA process and for the case when this conversion does not take place. It is found that the vibrational energy-storage capacity is extremely model-dependent. The vibrational energies at 1 000 years range from about 1047 to 1050 ergs, which are sufficiently large as a possible energy source for the X rays from the Crab Nebula, ft is shown also that the cooling times of neutron stars will not be significantly increased by the inclusion of the vibrational heating.
THE ANGULAR DISTRIBUTION OF FAST PHOTONEUTRONS FOR NUCLIDES WITH N ABOUT 56
Authors: Hussain S. M. , McNeill K. G.
Published: April 2011

Measurements have been made of the angular distributions of fast (E > 5 MeV) photoneutrons from eight elements in the region Z = 28 to Z = 50, and from lead, using threshold detectors. It is found that there is evidence for peaking of the anisotropy of these photoneutrons at the closing of the. N = 56 subshell.
SPECTROSCOPIC LINE ANALYSIS USING A GAUSSIAN AND LORENTZIAN CONVOLUTION TECHNIQUE
Authors: Farach Horacio A. , Teitelbaum Hector
Published: April 2011

In the case where the absorption curve is a convolution of Lorentzian and Gaussian shapes, it is possible to carry through an analysis which separates both contributions. We explain how to make this analysis, and we give general curves which are exemplified by an application to Tutton's salt.
IONISATION PAR IMPACT ÉLECTRONIQUE DE CO2 ET N2O
Authors: Carette Jean-Denis
Published: April 2011

The ionization curves of CO2 and N2O caused by electronic impact have been measured for various ranges of ionizing electron energy. For both ions, CO2+ and N2O+, a structure consisting mainly of breaks in the curve has been observed. Some of those breaks have been related to excited electronic states of the ions, and others, near threshold, to vibrational states.
BINDING ENERGIES OF HYPERNUCLEI FROM 2.3 BeV/c K− INTERACTIONS
Authors: Huang R. , Roalsvig J. P. , Sahni R. J. , Steinberg P. H.
Published: April 2011

Hypernuclear binding energies obtained from 43 uniquely identified mesic decays are reported here. The values are in good agreement with the previous data. Reported also are binding energies of two short-range mesic spallation hyperfragments.
INVESTIGATION OF THE HYPERFINE STRUCTURE OF DIVALENT MANGANESE IN A MAGNESIUM OXIDE LATTICE
Authors: Dyer Glenn L. , Woonton G. A.
Published: April 2011

Measurements have been made by the Endor technique on one-third of the hyperfine splittings of the divalent manganese ion 55Mn2+, present as a dilute substitutional impurity in a magnesium oxide crystal; the measured transitions were those associated with the electronic quantum numbers M = + 1/2 and M = −1/2. The measured energy levels of the ion are predicted to within a probable error of 6.4 × 103 Hz by the following spin Hamiltonian:[Formula: see text]This Hamiltonian is regarded as tentative, useful until further experimental results are available.Measurements were made along the cube axes of the crystals, at 31.7° to the cube axes, and at 45° to the cube axes in a plane that contains two cube axes. The values of the parameters in the spin Hamiltonian have been found to be:[Formula: see text]
RANGES OF Na, K, Kr, AND Xe IONS IN AMORPHOUS Al2O3 IN THE ENERGY REGION 40–1 000 KEV
Authors: Jespersgård P. , Davies J. A.
Published: April 2011

Range distributions of 24Na,42K, 85Kr, and 133Xe ions in amorphous Al2O3 have been measured in the energy region 40–1 000 keV. The experimentally observed values of the mean range and range straggling are in excellent agreement with the predictions of Lindhard et al. (1963), except at the higher energies, where the observed ranges are consistently larger than the predicted values.
V.H.F. RADIO AURORA: SIMULTANEOUS OBSERVATION OF AURORAL IONIZATION BY TWO SEPARATED RADARS
Authors: McDarmid D. R. , McNamara A. G.
Published: April 2011

Data from a Canadian v.h.f. radar network which operated during the IGY were analyzed to determine the aspect sensitivity of 48-MHz radio aurora. Two radars of this network simultaneously viewed a region of high-visual and radio-auroral activity. This paper is concerned with echoes which were obtained over a two-year period from auroral ionization simultaneously observed by these radars. The general properties of these simultaneous echoes were determined and are compared, where possible, with the corresponding properties of the overall set of echoes seen by each radar when looking independently at the same region. This comparison indicates that the mechanism responsible for simultaneous echoes is very probably the same as that which is responsible for the majority of radar echoes seen individually by the two radars. The spatial and temporal correlation between the simultaneous echoes and visual aurora is presented. The average aspect sensitivity of these echoes (48 MHz), which were obtained from simultaneous observations at off-perpendicular angles near 5° and near 20°, was found to be 1 dB per degree.
DISPERSION RELATIONS FOR PHONONS IN MAGNESIUM FLUORIDE
Authors: Katiyar R. S. , Krishnan R. S.
Published: April 2011

The lattice dynamics of magnesium fluoride have been investigated theoretically. The group theoretical method is used to decompose the dynamical secular equation at the center of the Brillouin zone. In order to get the expressions for all the infrared-active transverse and longitudinal modes, it is necessary to decompose the secular equation for the wave vector approaching zero along the two nonequivalent crystallographic axes, say y and z, of the crystal. Analysis of the results shows that a rigid ion model of the crystal with axially symmetric forces can provide qualitative agreement with the observed frequencies appearing in Raman and infrared absorption. The ions in the crystal are found to retain 70% of their charges, showing thereby the ionic character of the crystal. The dispersion relations for normal modes of vibration propagating along the (0 0 qz) and (0 qy 0) directions have been evaluated.
PHOTON CROSS CORRELATIONS IN A COUPLED BIMODAL SYSTEM
Authors: Williams Roscoe C.
Published: April 2011

When two atoms are coupled by an interaction potential, they can emit electrons simultaneously into different modes. For a coupled bimodal system, this effect (coupling) causes the line widths and amplitudes of the modes to differ.
ELECTROMAGNETIC RADIATION-PATTERN EFFECTS OF DIELECTRIC LAYERS
Authors: Harris J. H.
Published: April 2011

A formulation for the radiation pattern of a grounded magnetic line source in the presence of dielectric layers is obtained and the effects of differing permittivity variations are investigated. It is shown that relatively simple bounding functions may be established, and that layers may be employed to obtain both directive and smoothed patterns.
NORMAL-MODE ANALYSIS OF A SUPERFLUID MODEL
Authors: Knollman G. C.
Published: April 2011

An investigation is performed using normal-mode analysis on a quantum mechanical cell model whose general features are representative of 4He at low temperatures. Both random-phase and self-consistent field approximations are invoked. A Bogoliubov-type excitation energy spectrum is derived for the interacting Bose system, and the amplitudes of the system quasi-particles are obtained; these quantities are expressed in terms of zero-momentum occupation number. A relationship giving the temperature-dependent fractional occupation of the single-particle zero-momentum level is established, and special attention is devoted to the temperature extreme near absolute zero. An estimate is made of the zero-temperature sound speed corresponding to the special case of phonon excitation given by the model in low momentum. It is shown that at a critical temperature for which the zero-momentum occupation is depleted, the quasi-particles indeed become normal Bose particles. In first approximation, this critical temperature is akin in form to that obtained in treatments of ideal boson systems.
EXPERIMENTAL INVESTIGATION OF LANGMUIR PROBES
Authors: Clements R. M. , Skarsgard H. M.
Published: April 2011

Electron temperatures and densities measured in a weakly ionized helium afterglow with cylindrical double probes are compared with measurements obtained using a gated microwave radiometer and a microwave resonant cavity. The pressure was varied from 0.1 to 8.5 Torr. At low pressure, magnetic fields up to 0.11 T were applied. Independent of the values of the electron Larmor radii or particle mean free paths relative to the probe radius, the probes correctly measured the electron temperatures within an estimated random probable error of ±4% and a systematic error not exceeding ±4%. This demonstrates the validity, for the range of conditions studied, of a fundamental assumption of probe theory—that electrons in a retarding probe field are in a Maxwell–Boltzmann distribution at a temperature unaffected by the presence of the probe. Towards higher pressure the measurements show an increasing depression of the plasma density near the probe, associated with the diffusion to it. The applied magnetic field had no noticeable effect on the densities measured with the probes as compared with the cavity measurements.
INTERACTIONS OF 24 AND 27 GeV/c PROTONS WITH COMPLEX NUCLEI IN NUCLEAR EMULSIONS
Authors: Rao G. K. , Rao P. D. K. , Kamal A. A.
Published: April 2011

From the analysis of interactions of 24 and 27 GeV/c protons in complex nuclei, the scattered and cascade protons have been separated from the integral energy spectrum. An attempt has been made to separate interactions in CNO and AgBr statistically by the characteristics of their nuclear recoils. Fair agreement is reached in the frequency of events expected from the composition of the emulsion. The distribution of the number (ν) of target nucleons involved in the central collisions in AgBr is found to follow the Poisson distribution. The ratio of tunnel lengths in AgBr and CNO groups is consistent with the predictions of the tunnel model rather than those of the plural cascade theory. The variation of Ns with ν is also compatible with the tunnel model.
ROCKET MEASUREMENTS IN PROTON AURORA
Authors: Whalen B. A. , McDiarmid I. B. , Budzinski E. E.
Published: April 2011

Proton and electron intensities, energy spectra, and angular distributions derived from a recent rocket flight launched into a 40-rayleigh Hβ aurora are reported. High-intensity proton precipitation (~0.45 erg cm−2 s−1 for protons with energies above 30 keV) was detected throughout the flight above 100 km, whereas the electron intensity was above the limit of detectability for only a short time. The proton and electron spectra and angular distributions in the 20–60 keV energy range were found to be remarkably similar, with angular distributions being isotropic over the pitch-angle range 0–90°, and with e-folding energies of about 12 keV and 18 keV for protons and electrons respectively. The results are interpreted in terms of current magnetospheric models, and are shown to place certain restrictions on the source mechanisms.
MOLECULAR REORIENTATION IN FERROELECTRIC LITHIUM HYDRAZINIUM SULPHATE
Authors: MacClement W. D. , Pintar M. , Petch H. E.
Published: April 2011

The temperature dependence of the spin-lattice relaxation time T1 and of the second moment of the magnetic-resonance absorption signal has been determined for protons in powdered lithium hydrazinium sulphate over the range 80–480 °K. These measurements indicate that the hydrazinium ion is rigid only at very low temperatures. As the temperature is raised, the −NH3 group begins to undergo hindered rotation about the N–N axis with an activation energy of 4.2 kcal/mole and the effect of this motion on the line width becomes pronounced in the region of 85 °K. Further molecular reorientation begins above room temperature and is probably reorientation of the −NH2 group about either the N–N axis or the bisectrix of the H–N–H angle. Above 435 °K the hydrazinium ion begins to tumble about several axes and at 480 °K diffuses through the structure.
SPECIFIC HEATS AND DISPERSION CURVES FOR CsCl ON THE BASIS OF THE SHELL MODEL
Authors: Srivastava G. P. , Dayal B.
Published: April 2011

The shell model of Dick and Overhauser as developed by Cochran and Woods el al. has been applied to study theoretically the lattice dynamics of a cesium chloride crystal. The polarizabilities of both negative and positive ions have been taken into account in this treatment. The charges on the shells of the two ions come out to be of different magnitude. It is seen that the theoretical specific-heat variation with temperature based on this model is in fair agreement with experimental results in the range for which they have been obtained. The theoretical dispersion curves in the three symmetry directions are also given.
SCATTERING FROM A HALF-LOOP ON AN INFINITE PERFECTLY CONDUCTING PLANE
Authors: Plonus M. A.
Published: April 2011

Scattering from a small wire loop is derived using expressions of V. H. Weston. It is shown that the scattered field can be identified with two dipole-type scatterers, an electric and a magnetic dipole. Using image theory, scattering from a half-loop on a conducting plane is obtained. The scattered field consists of contributions of an electric dipole normal to the plane and a magnetic dipole normal to the plane of the half-loop. The equivalent scattering dipole moments are expressed in terms of the loop geometry and the orientation and polarization of the incident wave.
RAYONNEMENT FORTEMENT ACCRU PRÉSENTÉ PAR UNE ANTENNE ENROBÉE D'UNE GAINE DIÉLECTRIQUE ET D'UNE COUCHE DE PLASMA
Authors: Messiaen A. M. , Vandenplas P. E.
Published: April 2011

The plasma sheath existing between an antenna and a surrounding plasma layer plays an essential role. It is predicted that, for a given operating frequency, there exist certain plasma densities for which the system is resonant, and this very strongly enhanced radiation is fully confirmed by experiments. This combination of dielectric layer and plasma enables to tune an antenna even when its dimensions are much smaller than the vacuum wavelength. The influence of a static magnetic field is discussed.The same system can also be used as a frequency-sensitive receiving aerial.
THE SPIN AND MAGNETIC MOMENT OF CESIUM-138
Authors: Stinson G. M. , Archer N. P. , Waddington J. C. , Summers-Gill R. G.
Published: April 2011

Using source material isolated from the thermal neutron fission of 235U, an atomic beam investigation of 138Cs has been carried out. The results are I = 3 and [Formula: see text] nuclear magnetons. Calculations using a delta-function residual n–p force show that no pure shell-model configuration, appropriate to the mass, is capable of yielding the observed spin. Although the magnetic moment is just consistent with either (g7/2)7/2 or (g7/2)5/2 for the proton configuration and ƒ7/2 for the odd neutron, one may conclude that some configuration mixing is involved. The proton part of a plausible wave function is predominantly (g7/2)7/2 with a spin-5/2 admixture—either (g7/2)5/2 or (d5/2)5/2. In this respect it is similar to the wave function of 140La.
SECOND INTEGRALS FOR THE EXPLODING LOOP
Authors: Dodson C. T. J.
Published: April 2011

This note reports the computation of second integrals of the simplified equation for the exploding loop (Dodson 1967). A photograph shows a typical computer line-plotter output.The decrease in the period of the motion with increasing rest tension is given and confirms the prediction of the previous publication.
EDGE DIFFRACTION IN AN ARBITRARY ANISOTROPIC MEDIUM. I
Authors: Rosenbaum Shalom
Published: April 2011

Diffraction by a perfectly conducting half-plane embedded in a transversely unbounded region filled with a uniform, lossless but arbitrarily anisotropic medium characterized by a Hermitian dielectric tensor ε is studied. Formal solutions in terms of a plane-wave modal superposition (with the modal amplitudes determined via the Wiener–Hopf technique) are obtained. Asymptotic (short-wavelength) contributions (saddle-point contributions as well as contributions due to intercepted singular points) are considered. The asymptotic results are then cast into invariant, ray optical forms, amenable to a distinct physical interpretation.Mode coupling at the boundary gives rise to diffracted (lateral) waves as well as to geometric-optical (incident and reflected) waves. In addition to the "conventional" radially diffracted waves, one observes "secondary" lateral waves generated by the edge. In the short-wavelength limit the edge behaves as a virtual line source whose magnitude is proportional to the total (direct and lateral) field incident upon it. The asymptotic field solutions are valid, subject to the exclusion of some suitably defined transition regions, which are distinctly determined by the geometric-optical expressions. The various (asymptotic) wave constituents are shown to correspond to the anticipated results of geometrical optics.
EDGE DIFFRACTION IN AN ARBITRARY ANISOTROPIC MEDIUM. II
Authors: Rosenbaum Shalom
Published: April 2011

Diffraction by a perfectly conducting half-plane embedded in a transversely unbounded region filled with a uniform, lossless but arbitrarily anisotropic medium characterized by a Hermitian dielectric tensor ε is studied. Excitation is by a linearly phased line source of arbitrarily polarized electric and magnetic currents. Formal solutions are obtained in terms of a two-dimensional plane-wave modal superposition (over the entire range of the transverse wave numbers representing the incident (ηn) and scattered (η) waves). The original contours of integration in both the complex ηn and η planes are deformed simultaneously into their respective paths of steepest descent, and contributions to intercepted singular points are considered. Asymptotic (short-wavelength) analysis yields results which, despite their relative complexity, are cast into invariant, ray-optical forms, amenable to distinct physical (geometric-optical) interpretation.Mode coupling at the boundary gives rise to source-excited lateral waves as well as geometric-optical (incident and reflected) waves. In the short-wavelength limit, the edge behaves as a virtual line source whose magnitude is proportional to the total field incident upon it (which is composed of direct rays emerging from the source, as well as a lateral wave propagating along the boundary, towards the edge). Both the direct and the lateral waves are diffracted by the edge (i.e., coupled to edge-excited "radial" and "secondary" lateral waves) in a manner identical with that discussed in Part I.
ROTATIONAL STATES IN DEFORMED EVEN–EVEN NUCLEI
Authors: Gupta Raj K.
Published: April 2011

The deviations from the simple I(I + 1) dependence of the energy levels in the ground-state rotational bands on the hydrodynamical model of Bohr and Mottelson have been investigated for both regions of stable deformation. An interpretation of high spin states is looked for in terms of a nonrigid rotator with vibrations (harmonic oscillator type) taken as perturbation. In the framework of this model, the energy expression is obtained as a power series in the product of the ratio B/A and the weight factor I(I + 1), where A is related to the moment of inertia and B is the rotation–vibration coupling constant. The calculations are shown to be in good agreement with the experimental data.
KINETIC EQUATION FOR A GAS WITH LONG-RANGE ATTRACTION
Authors: Elliott R. A. , Sobrino Luis de
Published: April 2011

A classical gas whose particles interact through a weak long-range attraction and a strong short-range repulsion is studied. The Liouville equation is solved as an infinite-order perturbation expansion. The terms in this series are classified by Prigogine-type diagrams according to their order in the ratio of the range of the interaction to the average interparticle distance. It is shown that, provided the range of the short-range force is much less than the average interparticle distance which, in turn, is much less than the range of the long-range force, the terms can be grouped into two classes. The one class, represented by chain diagrams, constitutes the significant contributions of the short-range interaction; the other, represented by ring diagrams, makes up, apart from a self-consistent field term, the significant contributions from the long-range force. These contributions are summed to yield a kinetic equation. The orders of magnitude of the terms in this equation are compared for various ranges of the parameters of the system. Retaining only the dominant terms then produces a set of eight kinetic equations, each of which is valid for a definite range of the parameters of the system.
ESR SPECTRUM OF Fe+3 IN TOPAZ: I. FINE STRUCTURE
Authors: Thyer J. R. , Quick S. M. , Holuj F.
Published: April 2011

ESR spectrum of Fe+3 in topaz (Al2SiO4F2) has been investigated at X- and K-band frequencies. The spectrum, in addition to large zero-field splitting, also shows well-resolved h.f.s. due to 19F at some orientations. The spin-Hamiltonian parameters, which include b21 and b41, are given in the text. The spectrum has been interpreted to originate from Fe+3 impurity located at Al+3 sites. The implications of these results are considered briefly. The results of the analysis of the h.f.s. are to be published in the near future.
NONLINEAR EFFECTS IN THE DIPOLE RESONANCE OF A PLASMA COLUMN AT HIGHER R-F. POWERS
Authors: Gregory B. C. , Mourier G.
Published: April 2011

The increase of electron temperature as a function of the incident r-f. power of a cylindrical plasma column in a wave guide at the dipole resonance is studied. Measured values are consistent with the view that the electron temperature is limited by inelastic collisions. Section III of the paper uses an equivalent circuit model of the plasma column to explain theoretically the observed deformation of the dipole resonance curve with increasing incident r-f. power. All features of the experimentally observed deformation are successfully explained.
"VECTAL" REPRESENTATION OF THE WAVE FUNCTION AND ITS PHYSICAL MEANING
Authors: Lin C. S.
Published: April 2011

A new form of one-electron wave function, "vectal," is introduced. It is shown that an arbitrary CI geminal and a certain class of many-electron wave functions can be represented in a single-determinantal form in terms of the vectal. Eigenvalue equations for the vectal, similar to that of the Hartree–Fock theory, are derived and the vectal representation is shown to enable a formal interpretation of the CI theory in the Hartree–Fock manner. The eigenvalue, vectal energy, is interpreted as the negative of an ionization potential, in Koop-man's sense, of the system described by the CI wave function. It is also shown that the expectation value of any one-electron operator, [Formula: see text], where Ψ is the CI wave function, is expressible in terms of the expectation values of the same operator with respect to the vectals. The vectals are interpreted as the one-electron wave function in the CI space.A possible application of the vectal representation is briefly described, and the relationship between the vectal representation and the "scalar representation" is discussed.
TRANSPORT PROPERTIES OF PURE METALS AT HIGH TEMPERATURES: I. COPPER
Authors: Laubitz M. J.
Published: April 2011

This paper is the first of a series reporting our investigations into the high-temperature properties of the monovalent metals. It contains a description of the methods used in these investigations, and the results of measurements of the transport properties of pure copper, over the temperature range 300–1 250 °K. These results are compared with some previously published work, and also with standard theoretical expressions applicable to the monovalent metals.
ANALOGUE SPECTRAL ANALYSIS OF GEOMAGNETIC MICROPULSATIONS IN THE RANGE 10 TO 200 SECONDS
Authors: Ku C. C. , Jones F. W. , Geldart L. P.
Published: April 2011

An analogue method was used to compute the power spectra of three orthogonal micropulsation components recorded at Mont St. Hilaire, Quebec, Canada (geographic coordinates: N 45°32′, W 73°09′) on four selected days. The computed spectral peaks are plotted against Local Mean Time (E.S.T.) to show the diurnal variation of the micropulsations for the three components. In general, the geomagnetic oscillations in the range 10–200 s consist of several different periods which correlate well among the three components. The dominant periods (as shown by the dominant spectral peak) of the north–south component and the vertical component are in general the same. The dominant period of the east–west component is in some cases different from that of the other two. On some days the dominant periods vary; on other days they stay essentially unchanged.
MULTIPOLE POLARIZABILITIES AND SHIELDING FACTORS OF THE HELIUM ISOELECTRONIC SEQUENCE
Authors: Cohen M.
Published: April 2011

Analytical expressions are derived for the two leading terms in the Z expansions of the multipole polarizabilities and shielding factors of all members of the helium sequence. The derived numerical values of the octopole and hexadecapole polarizabilities are in excellent agreement with the estimates of Stewart (1961).