bluuebunny/crossref_metadata_2025 huggingface dataset:
Gain Distribution in a CO2 TEA Laser
Authors: Robinson A. M.
Published: April 2011

The distribution of small signal gain over 23 P- and R-branch lines in the 10.4 μm region of CO2 has been measured in a transversely excited high pressure CO2 laser system. The upper population density, the inversion density, and the temperature were determined by fitting a pressure-broadened gain distribution over the rotational–vibrational transitions at the time of maximum gain for pressures of 100, 400, and 755 Torr.
Dynamics of the CO2 Atmospheric Pressure Laser with Transverse Pulse Excitation
Authors: Gilbert J. , Lachambre J. L. , Rheault F. , Fortin R.
Published: April 2011

The dynamical processes responsible for laser emission in the pulsed pumping of a transversely excited atmospheric (TEA) CO2 laser are investigated. An explanation for the formation of the giant pulse is proposed on the basis of a gain-switching mechanism in which it is assumed that with short strong-current pulses a high population inversion can be achieved prior to the onset of laser action. The kinetics of the mechanism are described by means of a set of nonlinear rate equations idealized to a four-energy-state system. With suitable initial conditions on the populations, the transient solution of these equations for the mixtures CO2–He and CO–N2–He appears to be consistent with the major features of experimental observation.
Partly Nonlocal Potentials in Nuclear Matter
Authors: Singh Y. , Warke C. S. , Bhaduri R. K.
Published: April 2011

A set of phase-equivalent partly nonlocal two-nucleon potentials in the s state are constructed, with short range separable-type repulsion superimposed on a local attractive potential of longer range. Nuclear matter calculations with potentials of this type reveal qualitative differences when the results are compared with those obtained from phase-equivalent rank-two separable potentials. These differences are linked to the different behaviors of the two-body bound state wave functions generated by an attractive local potential and its phase-equivalent separable counterpart.
The Excitation of Resonances by a Dipole Antenna Inside a Hollow Cylindrical Plasma
Authors: Yip G. L.
Published: April 2011

The problem of the excitation of resonances by a dipole antenna inside a hollow cylindrical plasma is examined. The plasma is assumed to be cold, uniform, isotropic, and lossy. A transversely oriented point electric dipole antenna lying on the axis of the cylindrical plasma is the source under consideration. For a thin and lossless plasma, resonances are found to occur at the two frequencies corresponding to dipolar resonances in a hollow cylindrical plasma as derived earlier by, for example, Kaiser and Closs, and Vandenplas. In addition, there is also an antiresonance at the plasma frequency. The radiation resistance and radiation patterns of the plasma-covered dipole are presented to show the effects of the radii of the plasma tube, the signal frequency and the collision frequency. The possible practical implications of the present study as pertaining to the improvements of reentry communication and the excitation of plasma resonances in ionospheric irregularities are discussed.
The Absence of the Dip in Backward π+ Photoproduction Using a Narrow Resonance Model
Authors: Lee Paul
Published: April 2011

The absence of the dip in backward π+ photoproduction is examined with both the "Nγ–Nα exchange degeneracy coupled with duality" and the "I = 3/2 dominance" points of view. A uniform combination of beta functions is employed using no arbitrary satellite terms but including parity doublets of the Nα, Nγ, and Δδ trajectories.
Magnetic Field Dependence of Induced Torque in Copper
Authors: Datars W. R. , Holroyd F. W.
Published: April 2011

Induced torque in copper has been measured for field rotation in a (110) plane at magnetic fields up to 18 kOe. Induced torque from closed orbits tends toward saturation at high fields and is analyzed in terms of two parameters that depend on the magnetoresistance and Hall constant. These parameters are magnetic field dependent and provide a method of determining magnetoresistance. The temperature dependence of induced torque is given for temperatures between 1.4 and 40 °K and is explained by the change in resistivity with temperature. The closed-orbit induced torque is anisotropic. Induced torque in a Cu(Fe) sample is similar to that for pure copper and indicates that impurity scattering is not the major cause of the anisotropy. The anisotropy is attributed to variations in magnetoresistance as determined by the shape and topology of the Fermi surface.
Model Calculations for Lattice Vibrations in ND4Cl at 85 °K
Authors: Teh H. C.
Published: April 2011

The rigid ion–rigid molecule model of Parlinski is shown to give a reasonable description of the dispersion curves for ND4Cl at 85 °K with the addition of the ionic charge as a variable parameter to make a total of 11 parameters. A shell model involving 13 adjustable parameters is more satisfactory in describing the experimental values, however. Various frequency distribution functions have been calculated using the best fit rigid ion–rigid molecule model and shell model.
Magnetic Field Dependence of the Thermoelectric Power of Iron
Authors: Blatt F. J.
Published: April 2011

The thermoelectric power of iron exhibits a broad maximum of about 17 µV/K near 200 K. The relatively high temperature of this maxim and its dependence on alloying and cold work argue against phonon drag as the mechanism responsible for this peak. Recently, MacInnes and Schröder proposed that this peak derives from anisotropic (scew) scattering due to spin–orbit coupling, which may be simulated by a large effective transverse magnetic field. Their calculations, which reproduce experimental observations quite well, are based on an expression derived by Sondheimer that is valid for an ideal two-band model. According to this model and the suggestion of MacInnes and Schröder, the thermoèlectric power of iron should be strongly influenced by domain alignment. Measurements of the dependence of the thermoelectric power of iron in transverse and longitudinal magnetic fields reported here yield results contrary to the predictions of that model.
The Mean Square Force on Ions in Liquid Rubidium
Authors: Egelstaff P. A. , Page D. I. , Duffill C.
Published: April 2011

The scattered neutron spectra from a sample of liquid rubidium have been measured over the range of momentum transfer 4–8 Å−1. The full widths at half amplitude of these spectra are analyzed in terms of the mean square force on an atom. It is shown that the results are substantially in agreement with data on the solid metal and differ from that of a similar Lennard-Jones fluid.
Energies and Intensities of γ rays in the Decay of 79Sr
Authors: Ladenbauer-Bellis I. M. , Bakhru H. , Jones B.
Published: April 2011

The decay of 79Sr has been studied using high resolution Ge(Li) detectors. 79Sr was produced via the 69Ga(14N,4n) reaction. The half-life of 4.4 ± 0.2 min was assigned to 79Sr. A gamma ray of 105.4 ± 0.2 keV has been assigned to the decay of 79Sr.
Some Comments on Testing Quantum Electrodynamics in Elastic Particle–Antiparticle Scattering
Authors: Resnick L.
Published: April 2011

The photon propagator is assumed modified by the addition of a heavy photon of mass M and negative norm, in a conventional way of describing the possible breakdown of quantum electrodynamics. It is noted that because of interference between direct and annihilation diagrams, a dynamical zero can occur in the physical region of high energy elastic particle–antiparticle scattering, to lowest order in α. The position of this zero is a function of M. Several reactions are examined with a view to setting limits on M. The elastic scattering of transversely polarized e−e+ can be a sensitive probe for a finite M.
Radio Wave Propagation in Stratified Media with Nonuniform Boundaries and Varying Electromagnetic Parameters: Full Wave Analysis
Authors: Bahar E.
Published: April 2011

Full wave solutions are derived to the problem of radio wave propagation in stratified media with non-uniform boundaries and varying electromagnetic parameters. The analysis employs a complete set of forward and backward travelling waves. The continuous parts of the wavenumber spectrum constitute the radiation field and the lateral waves, and the discrete part of the spectrum is identified as the surface wave term. The solutions are not restricted by the approximate surface impedance concept and the source and receiver can be situated on opposite sides of the interface. Exact boundary conditions are imposed and the solutions are shown to be consistent with the reciprocity relationships.
Rainbows, Glories, and the Scalar Field Approach
Authors: Patitsas A. J.
Published: April 2011

The purpose of this study is to investigate the limitations, apart from polarization effects, of the scalar field in accounting for the phenomena of the rainbow and the glory. The scalar scattering intensity and the electromagnetic Mie scattering intensities are plotted and compared in great detail in the critical regions of the rainbow and the glory for spheres of various sizes and refractive indices. In addition chromaticity calculations based on the scalar and Mie intensities are shown and compared. It follows that the scalar field can adequately describe the rainbow. In addition, old conclusions regarding the colors of the main bow are confirmed but no supernumeraries can be expected for droplets with diameter less than 100 μ. A rainbow effect on lake surface is reported. It follows that the scalar field is inadequate to describe quantitatively the glory. It is shown that the first red ring of the glory is useless in determining droplet size, and that the Van De Hulst theory in its common form predicts larger droplet size by 10%.
Studies of a Porro-Prism Q-switched Nd3+–Glass Giant-Pulse Laser Oscillator
Authors: Hill K. O. , Campbell C. K.
Published: April 2011

Studies have been made of the output energy characteristics and energy utilization factor of an Nd3+– glass giant-pulse laser oscillator, Q switched by means of a rotating Porro prism. A modified set of three laser rate equations is presented, incorporating an experimentally determined switching loss function γ(t) and a terminal level relaxation time τ = 400 ns. As confirmed experimentally it is shown that, for a given excitation and geometry, an optimum switching speed exists for effecting maximum energy in the giant pulse output.
High Field Magnetoacoustic Investigation of the Fermi Surface of Tungsten
Authors: Kalejs J. P. , Perz J. M.
Published: April 2011

We have measured the frequencies of quantum oscillations in the attenuation of 20 MHz longitudinal ultrasonic waves in tungsten in magnetic fields up to 109 kOe. Our results agree well with the de Haas–van Alphen (dHvA) data of Girvan, Gold, and Phillips (GGP). In addition, we see features predicted by the empirical model developed by GGP but not observed directly in the dHvA studies. Specifically, we find strong evidence of the continuation of the ω branch (GGP notation) for the magnetic field H in the [Formula: see text] plane right to the [110] direction; we also observe splitting of the ξ branch for field directions near [111], but not to the extent predicted by the model. From the temperature dependence of the amplitudes of the quantum oscillations, we have deduced cyclotron masses for some orbits; these agree well with GGP and cyclotron resonance data.
On the Constant "A0" in the Richardson–Dushman Equation
Authors: Vijh Ashok K. , Lenfant Pierre
Published: April 2011

The enormous deviations in the observed magnitudes of the constant "A0" of the Richardson–Dushman equation from the theoretical value for various materials appear to be roughly related to the heats of atomization of the latter. This has been explained in terms of some erosion of the cathode during the measurements.
Brueckner Self-Consistent Study of 16O and 40Ca Using Phase-Shift Determined Potentials
Authors: Hodgson R. J. W. , Hoang Tran Duc
Published: April 2011

A self-consistent Brueckner calculation of the binding energy and single-particle energies of 16O and 40Ca is carried out employing an effective interaction which is determined directly from the two-body scattering data. The interaction is described by its harmonic-oscillator matrix elements. It is found that the results are quite sensitive to the form of the phase shift at high energies.
Electron Energy Distribution Functions in an O2 Glow Discharge
Authors: Rundle H. W. , Clark D. R. , Deckers J. M.
Published: April 2011

A Langmuir probe technique has been used to measure electron energy distribution functions in the positive column of a DC glow discharge in oxygen. The electron energy distribution function is shown to fit a functional form given by f(E) = CE1/2 exp (−BEn) where n = 1.6 ± 0.1; the average electron energies lie between 4.4 and 5.0 eV.
N2+ Meinel Auroral Spectra in the 1.5 μ Region
Authors: Gattinger R. L. , Jones A. Vallance
Published: April 2011

Auroral spectra of the N2+ Meinel bands in the 1.45 to 1.55 μ. region were obtained from very bright auroral displays at Fort Churchill in January 1972. The intensity of the [OI] 5577 Å auroral emission in the field of view of the spectrometer was monitored with a photometer to enable corrections for auroral intensity fluctuations during the spectral scans and reference to the standard auroral brightness to be made. Since an aurora as bright as about IBC III was required to produce emission features comparable with those from the hydroxyl system in the night airglow, very few spectra with prominent auroral features were obtained as an IBC III aurora seldom occurred. The results suggest that direct electron excitation of N2 is the major mechanism for populating the N2+ (A2Π)ν′ = 0 and 1 levels.
Spectrophotometric Measurements of Noctilucent Clouds
Authors: Harrison A. W.
Published: April 2011

Near infrared spectra of a NLC display are compared with spectra from the normal twilight sky for the regions 7850 to 9000 Å and 2.8 to 4.2 μ showing that NLC's are scatterers of solar radiation. Airglow hydroxyl rotational temperatures and intensities were monitored for several nights before and after the display but show no obvious correlation in behavior with this single NLC occurrence.
Thermoluminescence and X-Ray Stimulated Luminescence of CaF2:Eu Crystals
Authors: Ward R. W. , Whippey P. W.
Published: April 2011

The X-ray luminescence and thermoluminescence due to Eu ions in CaF2 have been investigated. Thermoluminescent glow curves of CaF2 single crystals containing several different concentrations of europium have been measured between 4.2 K and 400 K. Spectral analysis of the two major glow peaks at 92 K and 240 K shows that the luminescence is due mainly to Eu2+ ions. The available evidence suggests the thermoluminescence of Eu2+ in CaF2 is a hole-type recombination process similar to the generally accepted mechanism for thermoluminescence from trivalent rare-earth ions in CaF2. In addition to the Eu2+ emission, lines are observed at lower energies in the X-ray luminescence spectra due to Eu3+ ions in at least three different symmetry sites.
Penetrability Calculations Through a Double-Hump Barrier in Nuclear Fission
Authors: LeBoeuf J. N. , Sharma R. C.
Published: April 2011

The penetrability through double-hump barrier in nuclear fission processes is calculated in the JWKB approximation based on Fröman's F-matrix formalism. Particular attention is paid to coinciding classical turning points where other methods break down. A qualitative discussion of results is also included.
Properties of a New Nondifferentiating Method for Studying Structures in the Presence of a Distorted Background
Authors: Carbonneau R. , Bolduc E. , Marmet P.
Published: April 2011

A recently reported mathematical treatment is analyzed, which improves the detection of structures located over a strong continuum. This method does not have the drawbacks of the commonly used differentiation and may be used as an adjustable filter, selecting structures according to their natural width. Detection of autoionizing states in argon and measurement of the energy shift between the ionization thresholds of H2 and D2 are presented, as examples of application.
Calculated Potential Energy Curves of OH
Authors: Easson Ian , Pryce M. H. L.
Published: April 2011

A configuration-interaction calculation of the electronic energies of the OH radical has been performed, using from 34 to 46 configurations for the doublet states; and from 11 to 25 configurations for the quartet states. The results are presented for the six lowest states of 2Σ+, 2Σ−, 2Π, 2Δ; 4Σ+, 4Σ−, 4Π, and 4Δ symmetries. The calculations have been performed for a range of internuclear distances from 0.8 to 3 Å. The method of computation has been designed to give the kind of accuracy for the lowest three or four states of each symmetry which could be useful in the empirical analysis of the hitherto unanalyzed spectrum of OH in the 1850 Å region.
On the Origin of the Electric Field of Polarization in a Gravitational Plasma
Authors: Fridman M.
Published: April 2011

The theories developed to explain the expansion of charged particles from the atmosphere always involve an electric field of charge separation of gravitational origin. A theory is proposed replacing the quasi-neutral sources by a plasma polarization due to the external field of gravity.Assuming that the penetrated Debye clouds are distorted by gravity and hence provide the sources, the induced changes in the correlation function are evaluated. The formalism giving the polarization electric field is verified by using the solution of the differential equations for gravitation correlation in the simplest case of an electron and single ion plasma.
Elastic Scattering of 100 MeV Protons by 14N
Authors: Chao C. C. , Lee J. K. P.
Published: April 2011

The elastic scattering of 100 MeV protons from 14N has been studied and results were analyzed by the optical model. The optical potential parameters obtained were compared to those from the same reaction at different bombarding energies and also to those obtained from elastic scattering data of 100 MeV protons from other 1p shell nuclei.
Noncentral Force Model for h.c.p. Metals
Authors: Kushwaha S. S.
Published: April 2011

The elements of the dynamical matrix are separated into two parts : (i) a short-range closed-shell part and (ii) an ionic part. The effect of the former is calculated using noncentral forces involving central as well as angular forces whereas the latter part is evaluated on the lines of Krebs using a screened Coulomb potential. The calculated phonon frequencies along symmetry directions and θ–T curves for Mg, Be, and Tl have been plotted and compared with the experimental results.
Nuclear g Factors in 55Fe
Authors: Kerr P. G. , Gibb A. W. , Cameron J. A.
Published: April 2011

The (α,n) reaction on natural chromium has been used to study levels in 55Fe up to 2.5 MeV excitation. Intensities and angular distributions of the decay gamma rays were measured, yielding branching and E2/M1 mixing ratios. In a magnetized target of the alloy Cr20Fe80, the rotation of the angular distributions was observed. Using recently determined lifetimes for the excited states and the average internal field of 277 kOe measured in the target material by Mössbauer absorption, the following g factors are obtained:[Formula: see text]
On Conformally Invariant Spinor Field Equations
Authors: Barut A. O. , Haugen R. B.
Published: April 2011

An eight-dimensional spinor equation in the six-dimensional space with a conformally invariant mass does exist, contrary to a recent assertion.
Nuclear Magnetic Resonance in Ferromagnetic Fe2P
Authors: Koster E. , Turrell B. G.
Published: April 2011

The NMR of 31P and 57Fe has been studied in Fe2P using a pulsed spectrometer. Resonances have been observed at frequencies 17.5, 20, 77.5, and 86.6 MHz allowing the deduction of the hyperfine fields at the various atomic sites. These are Hn(Fe I) = 148 kOe, Hn(Fe II) = 123 kOe, Hn(P I) = 50.2 kOe, and Hn(P II) = 45.0 kOe. From the shift in the NMR frequency on application of an external magnetic field, the sign of the phosphorus hyperfine fields is shown to be positive. The temperature dependence of the 31P NMR frequency has also been studied and the data is well fitted by a T2 law. Domain-wall enhancement is investigated in the light of a pinned-membrane model. Finally nuclear 31P and 57Fe spin relaxation times are measured. The longitudinal relaxation is due to thermally driven domain-wall motions, and this mechanism also produces the transverse relaxation at high temperatures, although at low temperatures spin-spin coupling is evident.
The Lyman and Werner Bands of Deuterium
Authors: Bredohl H. , Herzberg G.
Published: April 2011

The Lyman and Werner bands of D2 have been measured under high resolution and their analysis has been extended. From this analysis the rotational and vibrational levels of the ground state of D2 have been evaluated up to the last vibrational level ν = 21 which lies only 2 cm−1 below the dissociation limit. The deviations of the observed ΔG(ν + 1/2) and Bv values from theoretical values given by Kolos and Wolniewicz on the basis of ab initio calculations are very small but systematic and are probably due to the neglect of nonadiabatic corrections in the theoretical calculations. Similar comparisons have been made for the lower vibrational levels of the B1Σu+ and C1Πu− states. Here the differences between theory and experiment are somewhat larger. The observed electronic excitation energies agree with the theoretical ones within 15 cm−1 for 1Σu+ and 8 cm−1 for 1Πu−.
A Balloon Study of the OH Airglow Emission From Evening Twilight to Sunrise
Authors: Moreels G. , Jones A. Vallance , Blamont J. E.
Published: April 2011

A balloon-borne interference filter photometer designed to measure the OH band emission at 2 μm was flown from Fort Churchill, Canada, during the night of August 1–2, 1968. Observations of the intensity of the Q branch of the 8–6 band are presented and compared with results obtained with a 1.66 μm OH photometer carried in the same gondola. The morning and evening twilight variations observed are in agreement with those predicted by models based on mesospheric ozone photochemistry. The observed nighttime increase in the OH emission is not predicted by the theoretical models.
The Electronic Spectra of Hg–In Alloys
Authors: Siskind Barry , Boiani James , Rice Stuart A.
Published: April 2011

We have made reflectance measurements on liquid Hg–In alloys at near-normal incidence from 0.14 to 4.0 μm. After describing our apparatus, the experimental results, and the treatment of our data we make the following interpretations:(a) that the peak in ε2 at about 8.5 eV consists of a superposition of a d-electron excitation and a plasma (or Hopfield) resonance;(b) that the peak in ε2 at about 5.8 eV is associated with a peak in the density of states and is a consequence of a scattering resonance in the In ion-core pseudopotential;(c) that concentration gradients and a diffuse transition zone at the surface of the liquid alloy may have a significant effect on the optical properties, not only in ellipsometric experiments but also in reflectance experiments;(d) that an excess reflectance which we find at our long-wavelength limit can be explained in terms of an anomalously large density of states at the Fermi level and that this is consistent with available Hall coefficient and magnetic susceptibility data.
The Field in a Narrow Circumferential Slot in a Coaxial Waveguide
Authors: Hurd R. A.
Published: April 2011

The first three terms in the expansion of the electric field in a narrow circumferential gap in the outer wall of a coaxial waveguide have been determined. Also found is the input admittance of an infinite, coaxially fed cylindrical antenna, a quantity of interest in the theory of sleeve antennas.
Examination of the Harmonic Oscillator Approximation in the Nilsson Model
Authors: Hird B. , Huang K. H.
Published: April 2011

The major shell mixed Nilsson model which includes hexadecapole deformations predicts states from the 1g9/2 subshell in the low lying energy level spectra of 25Mg–25Al in a way which is not found experimentally. The ground state spin cannot be explained with this model for reasonable values of the deformation. These difficulties are removed when a Saxon–Woods function is used for the radial dependence of the one body potential. A good fit to the experimental levels is then produced for accepted deformations, but only if the RPC terms is considerably reduced.
Mean Lifetime of the 1612 keV Level in 37Ar
Authors: Vérucchi M. J. , Vaillancourt R. , Cardinal C. , Taras P.
Published: April 2011

The recoil-distance method was used to measure the mean lifetime of the [Formula: see text], 1612 keV level in 37Ar. The level was populated via the 34S(α,n)37Ar reaction at Eα = 7.9 MeV. The mean lifetime was found to be 6.47 ± 0.22 ns.
Decay of 83Ym and 83Yg to Levels in 83Sr
Authors: Simpson M. L. , Kitching J. E. , Mark S. K.
Published: April 2011

The decays of 2.85 min 83Ym and of 7.06 min 83Yg have been investigated. Two photons are observed to be associated with the metastable decay, and one depopulates a 4.95 s metastable level at 259.3 keV in 83Sr. Seventeen γ rays are associated with the ground state decay, γ–γ coincidence and internal conversion measurements are carried out. Decay schemes are proposed with deduced log ft values for the various decay branches. Probable spin–parity assignments are given. The nature of the states involved are discussed within the context of the shell model.
Ground-State Energy of an Exciton
Authors: Hawton M. H. , Dubey P. K. , Paranjape V. V.
Published: April 2011

We propose a method which differs from the conventional approach used by several authors for calculating the shift in the ground-state energy, E1s, of an exciton. Our approach allows us to obtain the shift for values of binding-energy-to-phonon-energy ratio, β2, which are not restricted to the range [Formula: see text], as is the case with earlier approaches. In the limit of small β, our result for E1s reduces to the expression derived by earlier authors.
Multi-Configuration Hartree–Fock Correlation Study of 1s2s1S
Authors: Fischer Charlotte Froese
Published: April 2011

A correlation study is performed for the 1s2s1S state of helium to neon. It is shown that the Hartree–Fock approximation is poor, and that the two-configuration approximation [Formula: see text] is equivalent to a nonorthogonal Hartree–Fock approximation for which Koopmans' theorem holds. Additional configurations are introduced which account for 90% of the correlation energy.
Altitude Distribution of Hydroxyl Bands of the Δν = 2 Sequence in the Nightglow
Authors: Evans W. F. J. , Llewellyn E. J. , Jones A. Vallance
Published: April 2011

Rocket borne measurements of the altitude distribution of the hydroxyl nightglow emission in the Δν = 2 sequence have been made. Bands originating from the upper vibrational levels (5, 6, and 7) were measured with a band-pass filter in the 1.8 μ. spectral region and bands from the lower levels (3, 4, and 5) were measured in the 1.6 μ. region. The observed emission was distributed in a layer 10 km thick with a maximum at 87 km. In the altitude region below 90 km, the distribution of O2 (1Δ) measured on the same flight was similar to the hydroxyl profiles. These observed distributions extend over a narrower range of altitude than most previous observations, but agree well with the distributions predicted by model atmosphere calculations.
Levels in 153Gd and 155Gd Studied with the (p,t) Reaction
Authors: Løvhøiden G. , Burke D. G. , Waddington J. C.
Published: April 2011

States in 153Gd and 155Gd have been populated with (p,t) reactions induced by 18 MeV protons. In 155Gd, strong l = 0 transitions were found to the 3/2−[521] ground state and the 3/2− β-vibrational state. Excited rotational members of the ground state band and the β-vibrational band were also identified. Strong l = 0 transitions were observed to the ground state, the 129, 509, and 531 keV levels in 153Gd. The population of members of the previously suggested ground state band in 153Gd confirms the earlier 3/2−[521] assignment. It is proposed that the 129 keV level is a mixed state of which the major component may be the 3/2 1/2−[530] Nilsson state. The 509 keV (3/2−) and 549 keV (5/2−) levels populated in the present experiment are probably members of a β-vibrational band in 153Gd. No explanation is offered for the strongly populated 3/2− level at 531 keV.
Compound-Mirror Open Resonator
Authors: Lit John W. Y. , Lavigne Pierre , Tremblay Réal
Published: April 2011

Open resonators with compound end mirrors (spherical mirrors with the central portions replaced by plane mirrors) have been theoretically analyzed by the matrix method. The diffraction loss of such a compound-mirror resonator depends very much on the relative sizes of the plane and curved mirrors. It can be made very much lower or higher than the equivalent Fabry–Perot resonator. Field distributions are examined and a summary of the theoretical method is also given.
Unified Theories for Massive Spin 1 Fields
Authors: Shamaly A. , Capri A. Z.
Published: April 2011

A pair of sets of first-order differential equations is given. They contain as special cases all the known spin 1 theories except the Stueckelberg formalism. It is also known that all of these theories are essentially causal.
Analysis of a 1Δu–1Σg+ Transition of CS2 in the Near Ultraviolet
Authors: Jungen Ch. , Malm D. N. , Merer A. J.
Published: April 2011

The strongest features of the gas-phase absorption spectrum of CS2 in the region 2900–3300 Å (Kleman's V system) are shown to belong to a 1B2–1Σg+ transition, where the 1B2 state correlates with the upper Renner–Teller component of the π → π* 1Δu state of the linear molecule. The barrier to linearity is about 1300 cm−1, and the structure of the molecule in the zero-point level is r(C–S) = 1.544 ± 0.006 Å, [Formula: see text]. Transitions to the lower Renner–Teller component, 1A2(1Δu), have been identified in the region 3340–3500 Å: these consist of a progression of vibronic Δ–Δ bands and a weaker progression of Π–Π bands. This is a new type of electronic transition, which does not appear in cold absorption, but whose 'hot' bands derive an amount of intensity proportional to K2 through Renner–Teller mixing (in this case from the V system). The bands of both systems are very severely perturbed: possible causes of the perturbations are discussed.
Half-Life of the 482 keV Level of 181Ta
Authors: Lowe L. M. , Zmora H. , Prestwich W. V.
Published: April 2011

A delayed coincidence measurement of the half-life of the 482 keV level of 181Ta has been performed. In the analysis, careful attention was directed towards system nonlinearities and an accurate method of TAC calibration. The result is T1/2 = 10.81 ± 0.05 ns.
On the Production of Hypernuclei Using Fast Kaons
Authors: Esch Robert James
Published: April 2011

The differential cross sections for the production of definite lambda hypernuclear states are calculated for the reaction n(K−, π−)Λ° on nuclear targets of helium, carbon, and oxygen at incident momenta from 500 to 800 MeV/c. A direct interaction model is used, employing the single scattering, impulse approximation. It is shown that these predictions are very sensitive to the three-momentum transfer and to the wave function of the bound lambda in the hypernucleus. Possible experimental consequences are discussed concerning the observation of hypernucleus production by studying the missing mass spectrum of the emitted pion.
Subsurface Electromagnetic Fields of a Grounded Cable of Finite Length
Authors: Hill David A. , Wait James R.
Published: April 2011

The subsurface fields of a finite line source or current-carrying cable are examined. Some special cases, such as the low-frequency limit, are treated analytically, and some simple working formulas are obtained. The general field expressions are reduced to single integrals with finite limits that are evaluated numerically. It is shown that if the source cable is sufficiently long, the fields are approximated by those for an infinite cable. The results have possible application to downlink communication and radio location of trapped miners.
Frequency Dependence of Conductivity in Amorphous ZnTe
Authors: Webb J. B. , Brodie D. E.
Published: April 2011

The frequency dependence of conductivity in mature films of amorphous ZnTe (a-ZnTe) is found to be consistent with the hopping type conduction model proposed by Jonscher with a quadratic sequence of firing times. The frequency dependent part of the conductivity obeys a power law relation of the form [Formula: see text] where "n" takes the value of 0.50 ± 0.01 in the temperature range 167 K < T < 300 K, whereas the real part of the relative permittivity follows an ωn−1 dependence. Effects due to dipole relaxation are also observed and can mask the hopping conduction observed. No well-defined single activation energy is observed for the conductivity over the temperature range studied.
Etude de l'Excitation du Néon par Spectrométrie Electronique
Authors: Roy D. , Delâge A. , Carette J. D.
Published: April 2011

This paper presents the description of an electron spectrometer involving a monoenergetic electron source, a scattering chamber, and an energy analyzer. The results presented are the measurements which have been done over energy loss spectra of exciting electrons in neon, as a function of their energy of incidence and the scattering angle.
Determination of the Ideal Resistivity and of the Deviation from Matthiessen's Rule in Silver
Authors: Kos J. F.
Published: April 2011

Measurements of the temperature dependence of the electrical resistivity of strained and annealed samples of very pure Ag between 1.4 and 295 °K have permitted the unambiguous and precise determination of the ideal resistivity ρi and of the deviation from Matthiessen's rule ρM. Between 12 and 23 °K, ρi varies as[Formula: see text]and has been attributed to normal and umklapp scattering. Below 10 °K an additional term with a T3.86 ± 0.08 behavior appears and is attributed to one-step umklapp scattering. For samples with [Formula: see text], [Formula: see text] over the entire temperature range. Below 10 °K the variation of ρM with temperature and with defect concentration is described in terms of the theory of phonon-assisted defect scattering proposed by Klemens.
Lifetime of the 5s6p1P1 Level of Strontium and Related Oscillator Strengths
Authors: Kelly F. M. , Koh T. K. , Mathur M. S.
Published: April 2011

The lifetime of the second excited singlet P level, 5s6p1P1, of strontium has been measured using the Hanle effect of the 5s4d1D2 – 5s6p1P1, 7169 Å, transition. The lifetime of the 5s6p1P1 level is 3.64 ± 0.14 ns. Oscillator strengths for the transitions from the 5s6p1P1 level are discussed. There are large discrepancies.
Bulk Viscosity and Electron Mobility in Liquid Argon
Authors: Freeman Gordon R.
Published: April 2011

The purpose of this comment is to point out an unexpected correlation between the bulk viscosity of argon and the mobility of electrons in the liquid, and to suggest new ultrasonic experiments. Ultrasound and electrons are useful probes to study the liquid state.
Total Cross Section of 16O(p,α)13N from Threshold to 7.7 MeV
Authors: McCamis R. H. , Moss G. A. , Cameron J. M.
Published: April 2011

The reaction 16O(p,α)13N plays an important part in explosive oxygen burning in stars, and the magnitude of its cross section is important in various astrophysical models of stellar evolution. Therefore, the cross section for this reaction was measured from threshold to 7.7 MeV, which includes the range of astrophysical importance. The experiment was performed using an activation procedure, which is described. At the highest energies obtained, the cross section was compared to, and agrees very well with, earlier measurements. The reaction rate for this reaction was calculated, and was found to be much lower than the previous estimate for it.
Autoionization and Electronic Correlation in Atoms
Authors: Mayers D. F. , Rebelo I. , Sharma C. S.
Published: April 2011

By considering the particular case of the 2s21S state of helium, it is shown that in the Hartree–Fock approximation autoionizing states of atoms have square-integrable wave functions and are, therefore, bound states. It follows that autoionization is a correlation effect. The autoionizing states must have non-square-integrable wave functions. The origin of the breakdown of the square integrability is studied with the help of a spectral analysis of the first-order wave function.
Magnetoconductivity of Aluminum Computed by the Path-Integral Method
Authors: Douglas R. J. , Datars W. R.
Published: April 2011

The components of the electrical magnetoconductivity and magnetoresistivity tensors of aluminum were calculated by the path-integral method using a nearly-free-electron Fermi surface and a uniform relaxation time. Results are presented for longitudinal and transverse magnetoresistance, the longitudinal–transverse components, and the Hall term. The induced torque calculated from the computed magnetoresistivity components is in excellent agreement with measured anisotropy and field dependence of the induced torque. The torque anisotropy results primarily from the longitudinal magnetoresistance anisotropy which arises from variations with crystal orientation of the mean of the orbitally averaged longitudinal component of carrier velocity. The observed magnetic field dependence of the Hall coefficient is reproduced using a temperature-dependent ratio of the relaxation times for the electron and hole bands. The irreducible even-field Hall terms, which are calculated for field directions in the (112) plane, are discussed. The longitudinal–transverse components of magnetoresistivity can saturate at values as high as 0.16 of the zero-field resistivity, but the effects of the longitudinal–transverse magnetoconductivity on the magnetoresistance and Hall coefficients are small. Reported linear high-field magnetoresistance is discussed.
Induced Torque in Aluminum
Authors: Holroyd F. W. , Douglas R. J. , Datars W. R.
Published: April 2011

Torque on single-crystal spheres of aluminum induced by a rotating magnetic field was studied in fields up to 20 kOe at 4.2 K. The magnetic field was rotated in (112), (011), and (001) crystallographic planes. Anisotropy of the induced torque showed minima at [Formula: see text] and [Formula: see text] directions. It was reproducible in different samples and persisted in samples that had been strained by up to 8%. The torque anisotropy existed between 1.2 and 35 K. There was no evidence of open orbits. The induced torque tended towards saturation at high fields, and was attributed to closed orbits. The induced torque determined from a path-integral calculation of the magnetoconductivity, assuming the relaxation time to be isotropic and representing the Fermi surface by a modified single-OPW model which had no open orbits, is in excellent agreement with experiment.
Microwave Absorption and Relaxation Processes of Some Monosubstituted Benzenes and their Mixtures
Authors: Madan M. P.
Published: April 2011

The dielectric absorption of benzene solutions of some monosubstituted benzenes and their mixtures has been studied in the microwave region over a temperature range 6 to 60 °C. The relaxation times and the thermodynamic parameters for the activated states have been determined using the measured dielectric data. The results obtained have been discussed in terms of the molecular motion of the system. The values of relaxation time for single polar component solutions are in reasonable agreement at temperatures at which there are available known data. The relaxation times for the mixtures are consistent with the results obtained by other workers for simple liquid mixtures of polar molecules in dilute solutions which they investigated.
Extensions in the Spark Spectra of Tl III and Pb IV
Authors: Gutmann F. , Crooker A. M.
Published: April 2011

The atomic spectra of thallium were excited and photographed in the spectral region between 340 and 9000 Å using as light sources both an electrodeless discharge and a spark-in-helium.The line list of lead previously obtained in this laboratory was supplemented, in the 340 to 1000 Å region, using a spark-in-helium light source to provide excitation data.The 5d10nl series, l = 0 to l = 5, have been extended in Tl III, while the 5d10 6f and 5d10 7f terms have been found in Pb IV. Minor adjustments and additions have been made in the 5d9 6s6p configuration of Tl III and Pb IV. The 5d9 6s7s configuration was established in Tl III and Pb IV. The [Formula: see text], [Formula: see text] energy levels belonging to the 5d9 6s6d configuration have been found in Tl III and Pb IV. Energy levels in Tl III and Pb IV, with [Formula: see text], [Formula: see text], [Formula: see text], have been assigned to the 5d9 6p2 configuration, and a number of levels belonging to the 5d9 6s7p configuration in Tl III have been established. The number of classified lines in Tl III is 495, while in Pb IV, 367 lines now appear in the classified line list. The 5d101S0 ionizational potentials of Tl III and Pb IV are respectively 240 773 ± 5 cm−1 and 341 438 ± 5 cm−1.
Stimulated Emission in the Hydrogen Maser and the H Spin-Exchange Cross Section
Authors: Vanier J. , Brousseau R. , Larouche R.
Published: April 2011

Experiments are described in which the phenomenon of stimulated emission with a delayed maximum of power is observed in a hydrogen maser and is studied in some detail. The results are coupled to measurements of relaxation rates made through a pulse technique in which the hydrogen beam is modulated. A solution of the rate equations describing the phenomenon for a two-level model is obtained on an analog computer and is compared with the experimental data. From the comparison, we conclude that the phenomenon is explained by the assumed theoretical model. It is found also that the published values of the spin-exchange cross section of hydrogen are consistent with our experimental data.
An Infrared Spectroscopic Study of Quantum Diffusion in Solid Hydrogen
Authors: Boggs S. A. , Welsh H. L.
Published: April 2011

The fundamental infrared absorption band of almost pure solid parahydrogen was investigated for evidence of quantum diffusion of orthohydrogen molecules. A feature of the band, involving a reorientation of neighboring o-H2 pairs, was observed to increase as a function of the time after solidification. The rate constant characterizing the diffusional formation of o-H2 pairs was found to lie in the range 0.3–0.7 h−1 for o-H2 concentrations of 0.7–1.6% and temperatures 1.14–2.10 K. The values and concentration dependence of the rate constant are in good agreement with the theory of Oyarzun and Van Kranendonk. The infrared data also agree within the experimental error with NMR observations of Amstutz, Thompson, and Meyer.
Nuclear Reaction Studies of 151Sm
Authors: Nelson D. E. , Burke D. G. , Waddington J. C. , Cook W. B.
Published: April 2011

Properties of nuclear levels in 151Sm have been studied by measuring angular distributions for the 152Sm(d,t)151Sm reaction and spectra at several angles for the 152Sm(3He,α)151Sm and 150Sm(d,p)151Sm reactions. The reaction products were analyzed with a magnetic spectrograph and detected with photographic emulsions. Transfer l values were deduced from the (d,t) angular distributions and from the ratios of (3He,α) and (d,t) cross sections. The (d,t), (d,p), and (3He,α) reactions on targets of 151Sm were also studied in order to learn more about the wave function of the 151Sm ground state. The low-lying positive parity levels can be described by the Nilsson model with Coriolis and ΔN = 2 interactions included. However, the properties of the low energy negative parity states could not be explained as easily. No mixture of Nilsson states was found which could simultaneously explain the single neutron transfer intensities and the Coulomb excitation probabilities from previous measurements.
Temperature Dependance of Photocurrent Decay Times in Very High Resistivity, Zn-Compensated n-Type Silicon
Authors: Krishna V. , Rumin N.
Published: April 2011

The photocurrent decay in high resistivity, n-type zinc-compensated silicon photoconductors has been measured in the temperature range 230–300 °K. The bulk portion of the decay can be resolved into two strongly temperature-dependent exponential components. A bulk recombination model based on two defect levels was used to analyze the experimental data. Reasonably good agreement between experiment and theory could be obtained only if the two centers were assumed to be the photoconductivity sensitizing, double acceptor Zn−3/2, and the V−3/2 level due to the vacancy which is also a double acceptor. In contrast, the measurements could only be partly explained with models in which the V−3/2 level was replaced by the E center, the lower zinc level Zn−1/2, or the A center. Moreover, unreasonable values for some of the material constants had to be assumed with these latter models.
Two Emission Band Systems of SeO in the Photographic Infrared
Authors: Azam M. , Reddy S. Paddi
Published: April 2011

Two emission band systems of SeO consisting of 46 bands degraded to longer wavelengths have been observed for the first time in the spectral region 10 780–9490 Å. The vibrational analysis of one system which consists of several double-headed bands shows that it arises from the forbidden transition b1Σ+–X3Σ−. The double-headed bands have been analyzed as belonging to the 1Σ+–X3Σ−(F1) and 1Σ+–X3Σ−(F2,F3) subsystems. The separations between the corresponding band heads of these two subsystems are consistent with the expected value of ~ 2λ, λ(= 86.4 cm−1) being the spin splitting constant of the X3Σ− state derived previously from a detailed rotational analysis of the B3Σ−–X3Σ− (denoted earlier as the A3Σ−–X3Σ−) system. The vibrational assignments are confirmed by the observed isotope band heads of 82SeO,80SeO,78SeO, and 76SeO. The second band system, which consists of a single sequence of bands in the region 10 780–10 500 Å, is tentatively assigned to the probable forbidden transition (a1Δ)–(X3Σ−).
Lifetimes of the 5s7p and 5s8p1P1 Levels of Strontium and Related Oscillator Strengths
Authors: Kelly F. M. , Koh T. K. , Mathur M. S.
Published: April 2011

The lifetimes of the 5s7p and 5s8p excited singlet P level of strontium have been measured using the Hanle effect of the 5331 and 4755 Å transitions to the 5s4d1D2 level. The lifetimes of the 5s7p and 5s8p1P1 levels are 4.93 ± 0.35 and 5.46 ± 0.17 ns. The related f values are discussed.
High-K States in 176Hf
Authors: Khoo T. L. , Waddington J. C. , Johns M. W.
Published: April 2011

High-K bands in 176Hf have been populated in the (α,2n) reaction and the transitions between members of these bands separated from those involving low-K bands by means of delayed coincidence techniques. The 175Lu(3He,d)176Hf, the 175Lu(α,t)176Hf, and the 177Hf(3He,α)176Hf reactions have also been studied and used in conjunction with the (α,2n) data to determine the two-quasiparticle configurations of these bands. States up to spin 12 have been identified in the Kπ = 6+ bands based on the levels at 1333.1 and 1761.5 keV, in the Kπ = 8− bands based on the levels at 1559.3 and 1860.1 keV, and in a band of Kπ = 6− or 7− based on a level at 1798 keV. The strong mixing between the two-quasi-proton and two-quasi-neutron configurations characteristic of this nucleus poses an interesting theoretical problem.
A New Spectrum Associated With Silicon Monoxide
Authors: Bredohl H. , Cornet R. , Dubois I. , Remy F.
Published: April 2011

The vibrational and rotational analysis of a Σ–Σ transition, which was erroneously attributed to SiO+, has been refined and extended. This band system is tentatively attributed to a new 1Σ−–1Σ− transition of neutral SiO.