bluuebunny/crossref_metadata_2025 huggingface dataset:
Infrared spectrum and molecular constants of CO2 in the 1.4–1.7 μm atmospheric window by very high resolution Fourier transform spectroscopy
Authors: Maillard J. P. , Cuisenier M. , Arcas Ph. , Arié E. , Amiot C.
Published: October 2017

The spectrum of CO2 has been recorded in the 1.4–1.7 μm atmospheric window using the very high resolution Fourier transform spectrometer of the Meudon Observatory. This laboratory study has allowed the accurate determination of the spectroscopic constants previously evaluated from the Venus spectrum.
Resonance fluorescence spectra from a three-level atom interacting with a strong bichromatic field
Authors: Sharma M. P. , Villaverde A. Balbin , Mavroyannis Constantine
Published: October 2017

We have studied the fluorescence spectra arising from the interaction of a three-level atom with two strong electromagnetic fields whose initially populated modes are equal to the two atomic transition frequencies, respectively. The Green's function formalism has been used to calculate the excitation spectrum of the system. An expression for the spectral function describing the excitation spectrum of the system has been derived in a closed form in the limit of high photon densities. Numerical computation of the expression for the spectral function indicates that at each transition frequency there may exist either one pair or two pairs or three pairs of sidebands, in addition to the central peak, depending upon the relative strength of the Rabi frequencies involved.
Some results from small stars of nuclear emulsion at 24 GeV
Authors: Ahmad I. , Khan A. R. , Ahsan M. Z. , Zafar M. , Irfan M. , Shafi M.
Published: October 2017

The analysis of 400 stars with 2 ≤ Nh ≤ 7 has been performed to investigate the emission characteristics of protons, deuterons, tritons, and slow pions produced in interactions of 24 GeV/c protons in nuclear emulsion. The [Formula: see text] and [Formula: see text] distributions of these particles have been experimentally investigated. The dependence of [Formula: see text] and [Formula: see text] on the shower multiplicity, the angle of emission, and mass of the particles has been studied.
Plasma expansion produced by a long-pulse CO2 laser
Authors: Neufeld C. R. , Lachambre J. L.
Published: October 2017

We have studied the plasma expansion produced when a 25 ns CO2 laser pulse is focussed onto a massive aluminium target. The maximum laser power density available was 2 × 1012 W cm−2 in a focal spot of approximately 250 μm in diameter. Charge collector measurements of the ions in the blow-off plasma indicate that an isothermal expansion model best describes the motion of the bulk of the plasma ions. Strong competing effects thus seem to inhibit the establishment of the steady-state regime expected for sufficiently long laser pulses, although faint indications of the beginnings of such a trend may be present.
Some electrical properties of amorphous Cd3As2
Authors: Enns D. I. , Brodie D. E.
Published: October 2017

Amorphous films of Cd3As2 were fabricated by vacuum deposition at pressures less than 10−8 Torr. Conductivity and Hall measurements are reported for the amorphous and crystallized films between 125 and 300 K. Electron mobilities in amorphous films as large as 300 cm2 V−1 s−1 are observed at room temperature in the higher conductivity samples. Amorphous Cd3As2 is a degenerate semiconductor with activation energies between 0.006 and 0.012 eV observed in the different samples. Thermoelectric power measurements agree only qualitatively with this model with [Formula: see text].
Gravitational synchrotron radiation in the metric of a new theory of gravitation
Authors: Mann R. B. , Moffat J. W.
Published: October 2017

The wave equation for a scalar field ψ is solved in the background metric of a new theory of gravity, based on a non-Riemannian field structure with a nonsymmetric Hermitian gμν. In contrast to the solution of the problem in a Schwarzschild background metric, in which only orbits close to r ~ 3M yield significant gravitational radiation, the new metric leads to an effective potential with stable orbits for a substantial range of r. The solution yields ψ = (1 − ℓ4/r4)−1/2ψGR where ℓ is a new integration constant. The null surface r = ℓ determines an astrophysical object called a "deflectar", which for ℓ > 2M conceals the Schwarzschild black-hole event horizon at r = 2M. As r → ℓ the gravitational synchrotron radiation increases to infinity. The actual power output of gravitational radiation for physically allowed stable orbits closest to r = ℓ is estimated, demonstrating that a deflectar is a potentially strong source of gravitational radiation.
Linearization of the Tc equation
Authors: Jain S. C. , Kachhava C. M.
Published: October 2017

Replacement of the Debye θD by the average phonon frequency in Rowell's linear Tc equation for superconducting materials not only improves his results but also describes the experimental results accurately and consistently for the various superconducting systems which cover the entire range of λ between 0.75 and 2.6.
The high spin states in 147Tb excited by the (6Li,3n) reaction
Authors: Khan Tasneem A. , Johns M. W.
Published: October 2017

High spin states in 147Tb have been excited by means of the 144Sm(6Li,3n) reaction and studied by means of γ-ray and electron measurements. Gamma-ray singles, excitation functions, angular distribution, linear polarization, γ–γ coincidence, and internal conversion measurements have been made. These have led to unambiguous spin and parity assignments to many levels and to lifetime determinations for two states. The resulting level scheme is discussed and compared with recent calculations.
Some observations of ionospheric ion drift motions at Fort Churchill
Authors: Brooks W. S.C. , Koehler J. A.
Published: October 2017

A "ram-sensor" ion motion detector was flown on four sounding rockets from Fort Churchill. For two flights, during which a magnetic disturbance was observed on the ground, large horizontal ion motions were observed along with some turbulence. The remaining two flights were at times of little ground magnetic activity and the ion motions tended to be more aligned with the magnetic field.
Evidence from positron annihilation of anomalously low vacancy density in some metals with low melting points
Authors: MacKenzie I. K. , Fabian J.
Published: October 2017

Measurements of the Doppler broadening of the annihilation energy spectrum in In, Sn, and Tl indicate anomalously low vacancy density below the melting temperature, Tm. In these metals the ratio of the threshold temperature for trapping by vacancies, vTt, to the temperature of melting, Tm, takes values of 0.76,0.88, and 0.70, in contrast to the value of 0.63 found in most close-packed metals. The vacancy formation enthalpies, H1vf, deduced from the threshold temperatures are 0.42, 0.57, and 0.52 eV for In, Sn, and Tl. There is no consistent pattern in the prevacancy behaviour of these metals. The positrons seem to sense the potential white–gray transition in β-Sn, even though no detectable fraction of the material experiences a phase change.
Millimetre wave spectrum of methyl mercaptan
Authors: Lees R. M. , Mohammadi M. Ali
Published: October 2017

An investigation of the rotational spectrum of CH332SH, one of the most recent molecules to be detected in the interstellar medium, has been carried out over the 25–107 GHz region. The frequencies of a-type Δk = 0 R-branch transitions have been measured for the J = 1 ← 0 up to J = 4 ← 3 multiplets for torsional states νt = 0–3. In addition, many P-, Q-, and R-branch transitions with Δk ≠ 0 have been identified in order to provide a catalogue of lines for potential radio astronomical applications. Improved values of rotational and centrifugal distortion constants, a-type torsion–vibration–rotation interaction constants, and torsional barrier parameters (V3 = 444.76 cm−1; effective V6 = −2.07 cm−1) have been determined from least-squares analyses of the spectra.
The spin XY model. V. Moments of the spin–spin correlations in three dimensions
Authors: Betts D. D. , Grundke E. W.
Published: October 2017

Ninth degree high temperature expansions have been obtained for all transverse spin–spin correlations of the [Formula: see text] model on the simple cubic and body centred cubic lattices. Analysis of the series for the second and fourth moments of the correlations yields the estimate of v = 0.689 ± 0.010 and estimates of critical amplitudes. No evidence for violation of hyperscaling is found.
Neutrally-stable tearing modes of a sheet pinch: effect of conducting walls
Authors: Shivamoggi Bhimsen K.
Published: October 2017

Neutrally-stable tearing modes of a sheet pinch are studied. In particular, an analytical investigation is made of the effect of conducting walls on the tearing modes of a sheet pinch. The stabilizing effect of the conducting walls is shown to arise through a reduction of the range of unstable wavenumbers.
New method for measuring earth albedo
Authors: Coombes Charles A. , Harrison A. W.
Published: October 2017

The earth surface albedo can be derived from measurements of the hemispherical distribution of the downward radiation flux from an observation point near the earth's surface. The underlying theory and practical suggestions for application of the method are presented.
Les coefficients du viriel de la constante diélectrique et de la pression des gaz imparfaits : mélange N2O–argon
Authors: Launier R. , Bose T. K.
Published: October 2017

Dielectric and pressure virial coefficients for six different mixtures of N2O–argon have been measured at 30.1 °C. The quadrupole moment of N2O calculated from the dielectric second virial coefficient of the mixture N2O–argon is 3.4 × 10−26 esu cm2. This value is identical to that obtained by Kirouac and Bose from the dielectric second virial coefficient of pure N2O. The good agreement confirms the model developped by Bose and Cole for quadrupolar molecules.
A simple technique for performing higher order quantum chromodynamic calculations
Authors: Sen A. , Sundaresan M. K.
Published: October 2017

A simple calculational technique is presented for performing higher order calculations in quantum chromodynamics with relative ease. The essence of the technique is to rearrange the numerator involved in multidimensional Feynman integrals in such a way as to cancel as many denominator factors as possible, leading thus to a few simple integrals which are easily handled by using dimensional regularization. As an example, this technique is used to check some of the recent results obtained by Dine and Sapirstein and Celmaster and Gonsalves.
The infrared spectrum of di-imide near 7.6 μm
Authors: Hallin K-E. J. , Johns J. W. C. , Trombetti A.
Published: October 2017

The gas phase spectrum of N2H2 has been investigated in the region of 7.6 μm at a resolution of about 0.06cm−1. Two bands have been identified; one, near 1288 cm−1, is a type C band and must correspond to ν4 (the hitherto unidentified Au torsional mode), and the other, near 1317 cm−1, is a type A–B hybrid and corresponds to ν6 (the Bu bending mode). Analysis of the spectrum is complicated by the simultaneous presence of strong A-type and B-type Coriolis interactions which couple the observed levels.
On the surface tension and shear viscosity of square-well fluids
Authors: Datta S. K.
Published: October 2017

Closed analytical expressions for the surface tension and the shear viscosity coefficient of a square-well fluid have been obtained using the mean spherical model approximation (MSMA) and the exact hard sphere equation of state given by Carnahan and Stirling. The expressions are then used to calculate these properties for some real fluids. The fair agreement between the calculated and experimental values in the case of several symmetric nonpolar molecules, suggests that the representation of the attractive tail by a square-well potential is a satisfactory one even in the calculation of these complex properties and that the use of MSMA in the elucidation of the equilibrium and transport properties of liquids provides a more or less satisfactory and convenient approach.
A general stability analysis for immiscible viscous displacement in a porous medium
Authors: Spanos T. J. T.
Published: October 2017

A perturbation of an immiscible displacement process causes relative motion of the two fluids involved. At the macroscopic scale such relative motions are considered to propagate throughout the porous medium in the form of fluid waves. A description of these waves is given on surfaces of constant saturation in a similar fashion to the description of a surface wave propagating on the interface between two fluids. In the porous medium, however, the wave propagation is not restricted to the surface of constant saturation and as a result one obtains a wave equation that is both dissipative and diffusive.A stability analysis is also considered for the immiscible displacement process. Here, a characteristic time for instability to occur can be calculated when the inertial terms are included in the equations of motion. Also a generalization of the wave equations and stability criteria are considered for an inhomogeneous porous medium.
On embeddings of the Kerr geometry
Authors: Sharp Nigel A.
Published: October 2017

The use of isometric embeddings of curved geometries reveals their intrinsic structure in a way that is readily appreciated. This is done for 3 two-surfaces sliced from the Kerr metric which describes a rotating black hole: the equatorial plane, the event horizon, and the ergosurface.
Further improvement in the etching of soda glass detectors
Authors: Gomber K. L. , Singh V. P. , Yadav J. S. , Sharma A. P.
Published: October 2017

Nascent hydrogen has been used for removing the "etch product layer" formed during etching of soda glasses in HF. The solution so developed has two advantages, viz., no heat is produced during etching, and the strength of the solution is maintained until the tracks are completely developed. Various track development properties of soda glass detectors have been studied using this solution, and the optimal etching conditions are deduced. A detailed study shows an increase in the largest observable diameter from 47.0 to 107.5 μm. The etching efficiency is found to increase from 39.8 to 48.3%, and the registration threshold angle reduces from 42.5 to 38°. The activation energies for bulk and track etching rates have been calculated. The spectrometric response of soda glass detectors to fission fragments of 252Cf has also been investigated using the new etching solution. A distinct improvement in the energy resolution of soda glass detectors is observed with the use of the new etchant.
Entropy principle as a restrictive condition on kinetic equations
Authors: Grmela Miroslav
Published: October 2017

A family of kinetic equations involving undetermined quantities is introduced. The requirement that the kinetic equations are compatible with equilibrium thermodynamics implies a compatibility condition restricting the freedom of choice of the undetermined quantities.
Real-space renormalization and the Baxter–Wu model
Authors: Jan Naeem
Published: October 2017

The lower-bound renormalization group approximation developed by Kadanoff and co-workers is modified by the introduction of a novel form of the weight function which preserves the ground states of the Baxter–Wu model. The approximation is applied to this model and the problems encountered are discussed together with the implications of this approach for other real-space approximations. The relevant exponents (exact) obtained are 1.363 (1.50) and 1.879 (1.875) and the critical coupling KC31 is 0.4558 (0.4407).
Longitudinal correlations in proton–nucleus interactions at 70 GeV/c in emulsion
Authors: Bhattacharjee D. K. , Daftari I. K. , Roy T.
Published: October 2017

Single- and two-particle inclusive rapidity distributions in proton–nucleus interactions in emulsion are presented. Analysis of two-particle rapidity correlations shows a clear evidence for short range correlations in the central region, independent of the target size.
Charge transfer associated with lithium insertion in Mo1−yNbyS2 layered compounds
Authors: Py M. A. , Haering R. R.
Published: October 2017

The Mo1−yNbyS2 layered compounds form solid solutions. The coordination of the Mo and Nb atoms by S atoms is trigonal prismatic over the entire range of composition, 0 ≤ y ≤ 1. The [Formula: see text] band, separated from the other d-bands by a bandgap of the order of 1 eV, contains y empty states per formula unit. For y ≤ 0.6, Li/LixMo1−yNbyS2 electrochemical cells reveal a sharp voltage drop of V(x) at a critical composition x which is correlated to y by [Formula: see text]. This result clearly establishes the transfer of one electron per intercalated lithium (x ≤ 0.6) to the [Formula: see text] band of the host.Electrochemical cells, made with samples whose X-ray diffraction spectra suggest the presence of structural disorder in the host lattice, show a less abrupt voltage drop near xc, in qualitative agreement with the influence of disorder on the electronic density-of-states distribution N(E) near a band edge. The origin of the voltage drop observed for LixMo0.2Nb0.8S2 is not fully established.
Half-life of rhenium: geologic and cosmologic ages
Authors: Naldrett Stanley N.
Published: October 2017

The transition by beta emission of 187Re to 187Os would offer an attractive method of determining geologic and cosmologic ages if the decay rate of 187Re was known. An improvement in the determination of the decay rate has been accomplished using an organic compound of rhenium in liquid scintillation counting that is monitored by standards of other pure beta emitting isotopes. The half-life of 187Re is estimated to be (3.5 ± 0.4) × 1010 yr.
Ab initio SCF-MO calculations on AlO4 centres in alpha-quartz. I.
Authors: Mombourquette Michael J. , Weil John A. , Mezey Paul G.
Published: October 2017

Ab initio SCF-MO calculations were done on nine-atom and fifteen-atom clusters designed to simulate alpha-quartz, i.e., a [SiO4]0 unit, and aluminum impurity centres [AlO4]−, [AlO4]0, and [AlO4]+ in quartz, terminated with protons or SiH3 groups. The geometry of the small model of each of these centres was optimized. Using these models and the enlarged versions thereof, calculated values for relative total energies, various static structural parameters, electron spin densities, net atomic charges, and orbital energies are compared with experimental data from spectroscopic and other techniques, especially high resolution electron paramagnetic resonance. The calculated results agree remarkably well with experiment. Thus it is evident that small clusters of atoms can be used successfully to simulate the local surroundings of a substitutional Al ion in quartz, i.e., the short-range effects are the most important.
Generalized difference equation for the three-dimensional Ising ferromagnet
Authors: Frank B. , Cheung C. Y.
Published: October 2017

The difference equation method of Frank, Cheung, and Mouritsen (FCM) is made self-consistent by relaxing an assumption of the theory which pertains to the correlation of a spin with its nearest neighbour. The full set of A = 1 and I − δ equations and U equations is brought into play, with the U2 = T2 = (1/4) (1 − 1/F(1)) double equation replaced by a single relation between U2 and T2. The resulting ferromagnetic transition temperatures for the cubic lattices are consistent with the series results to within about 2%. The correlation functions are much closer to the series results than those of FCM.
Polarization analysis of induced gratings in nematic liquid crystal films
Authors: Fuh Y. G. , Code R. F.
Published: October 2017

A detailed analysis of classical diffraction on the optically induced phase gratings in thin films of the nematic liquid crystals 5CB, 6CB, and MBBA is presented. It enables a quantitative separation of thermal contributions from reorientational contributions to the gratings to be made by a simple measurement of the gratings' diffraction efficiency with a polarized probe laser.
Ion-acoustic solitons in a two electron-temperature plasma consisting of warm ions
Authors: Murthy P. N. , Tagare S. G. , Abrol P. S.
Published: October 2017

The effect of finite ion temperature and a small concentration of a cooler electron component on the width and phase velocity ion-acoustic solitons in a plasma with adiabatic ions and isothermal electrons with two electron-temperatures is investigated. A small concentration of a cooler electron component leads to effects qualitatively different from those obtained in a single-electron temperature plasma. By using hydrodynamic equations for warm ions and two-electron temperature plasma, Korteweg–de Vries equation is derived.
Effects of underlayer and surface roughness on the attenuated total reflection spectra of silver films
Authors: Pinard Alain , Girouard Fernand E. , Truong Vo-Van
Published: October 2017

When studying the effects of roughness on surface plasmons produced by the method of attenuated total reflection (ATR), one can deposit an aggregated or wavy underlayer on the prism surface before overcoating it with the same metal used for the underlayers. In the present work, aggregated silver films have been overcoated with a second silver layer, making a total film thickness of 52.5 nm. The ATR spectra of these systems were shown to be greatly influenced by the final state of the underlayer as well as the roughness at the silver–air interface. Results suggested that even after overcoating, the underlayers remained partially aggregated. The roughness at the silver–air interface was found to be less important than the thickness of the original, noncoated, aggregated underlayer.
Lattice dynamics of ionic molecular crystals in the rigid ion approximation, phases II and III of sodium superoxide
Authors: Fracassi Pier Francesco , Klein Michael L. , Della Valle Raffaele Guido
Published: October 2017

Quasi-harmonic lattice dynamics is developed for ionic molecular crystals, within the framework of the rigid ion approximation. Long-range electrostatic potentials as well as short-range atom–atom interactions are discussed, making extensive use of the Ewald long wave method. A computer program based on this theory has been developed, and phonon calculations have been carried out for phases II and III of solid Na+O2−. The calculated quantities are then compared with experimental data.
A slightly model dependent relation between Q and η for the deuteron
Authors: Butler M. N. , Sprung D. W. L.
Published: October 2017

A "model independent" relation between Q and η due to Biedenharn and Blatt is corrected and improved. A simple three-parameter Hulthén–type wave function for the deuteron is introduced.
Dilute Potts chain in a magnetic field
Authors: Chaves C. M. , Riera Rosane
Published: October 2017

The Potts lattice gas in the presence of a uniform magnetic field is solved exactly in one dimension. For negative values of the exchange parameter, the magnetization curve exhibits two or three steps, depending on the concentration of vacancies. These steps arise as a result of the competition between the exchange interaction and the magnetic field, and are associated with different structural distributions of vacancies and the magnetic ordering of one or both sublattices.
Method of lensless, no-aperture, one-step rainbow holography: theory, practice, and applications
Authors: Grover C. P. , Lessard R. A. , Tremblay R.
Published: October 2017

We introduce an innovative modification in the technique for making rainbow holograms based upon synthesization of a modulation equivalent to a slit in the object wave. Such a simulation of the slit function is achieved by imparting a suitable in-plane motion to the diffusing background of the object transparency. It is shown that the plane of localization of the synthesized aperture can be positioned anywhere with respect to the object by using a properly shaped illuminating wave. Thus, the object itself rather than its real image is directly responsible for the rainbow hologram formation making the imaging lens unnecessary. A converging or a diverging spherical wave is used to illuminate the object transparency backed by a ground glass. The image reconstruction takes place in accordance with the conventional rainbow holographic process, with the synthesized aperture occupying the plane of convergence or divergence of the object wave as the case may be. We present a theoretical analysis of this novel method of rainbow holography and give some supporting experimental results. This is followed by its application to the visualization of phase objects and a discussion of the quality of the reconstructed images.
N = 2 supergravity in the presence of an external magnetic field
Authors: McKeon Gerry
Published: October 2017

The effective Lagrangian to one-loop order is calculated for N = 2 supergravity in flat space-time in the presence of a constant external magnetic field. The divergences that occur are not renormalizable; this is not unexpected since the background fields do not satisfy the classical equations of motion.
Interference fringes arising from strong coupling in multiple exposure thick absorption holographic gratings
Authors: Couture Jean J. A. , Lessard R. A.
Published: October 2017

Multiplex holograms can generate modulated interference fringes imaged onto the surface of the recording medium whenever the N reconstructed object waves have a small angular separation. At this reconstruction stage, a strong coupling arises due to the vicinity of the recorded gratings and the small differences of their spatial frequencies. Diffraction efficiency expressions describing the effects of such a coupling are deduced.
Comportement d'une mince couche d'huile irradiée en infrarouge
Authors: Ledoyen F. , Cormier M.
Published: October 2017

A theoretical model is proposed to explain the physical behaviour of a thin oil film (≈ 1 μm) on a glass substrate when this film is irradiated by an infrared beam. Using the concepts of viscosity, surface tension, and disjoining pressure, this model gives an interpretation of the experimental results already published by authors who have used such a system as an infrared holographic recording medium. The good correlation obtained suggests that the techniques used by these authors could be advantageous in the study of thin film (0.05–1 μm) properties.
Raman spectra of a graphite surface implanted with
Authors: Mathur M. S. , Derenchuk V. P. , McKee J. S. C.
Published: October 2017

The surface of a graphite wafer was bombarded with [Formula: see text], and the Raman spectrum of the implanted surface obtained. Formation of a polycrystalline layer and the synthesis of several deuterated methanes have been demonstrated. The possibility of the formation of complexes involving C, H, and D has also been established.
A study of inelastic hadron–nucleus interactions at 50 and 400 GeV
Authors: Ahrar H. , Ahmad S. , Zafar M. , Irfan M. , Shafi M.
Published: October 2017

Some results on multiplicity, mean normalized multiplicity, and pseudorapidity distributions of shower particles produced in pion–nucleus and proton–nucleus collisions at 50 and 400 GeV are presented and discussed. From the study of the pseudorapidity distributions, it is found that the projectile fragmentation is mass independent and the target fragmentation depends upon the target size. The effect of nuclear mass on the forward–backward asymmetry is also examined by using the grey particle multiplicity data. Upon using the additive quark model, a new kind of nuclear scaling is observed between RA4, in terms of created charged particles and [Formula: see text].
Pseudorapidity distribution and cluster formation in 50 and 400 GeV/c hadron–nucleus interactions
Authors: Irfan M. , Khushnood H. , Shakeel A. , Khan A. R. , Shafi M.
Published: October 2017

From the study of the pseudorapidity, η, distributions of charged shower particles produced in 50 GeV/c π− – nucleus and 400 GeV/c proton (p)–nucleus collisions, and their dependence on various parameters, the maxima of η distributions are noticed to shift towards smaller values of η with increasing Ng. Bimodality in the η distributions for all Ng groups has been observed to be completely absent in 50 GeV/c π− – nucleus interactions. Furthermore, the value of [Formula: see text] is found to decrease monotonically with increasing Ng, Ns, and Nh. The dispersions of the rapidity distributions D(η) do not, however, demonstrate any tendency of appreciable change with increasing Ng, except in the region of small Ng values. Finally, study of rapidity-gap length distributions reveals that the two-particle short-range correlations play a dominant role while the contribution of long-range correlations seems to be quite small.
Some exact anisotropic solutions in general relativity
Authors: Krori K. D. , Borgohain P. , Devi Ranjumani
Published: October 2017

Some exact solutions for anisotropic matter are worked out in the framework of general relativity. Four such solutions are obtained by a suitable modification of four well-known solutions by Tolman, viz., Tolman's solutions III, IV, V, and VI. The degree of anisotropy is determined by a parameter, and the range of values this parameter will have under realistic situations is calculated for all four classes. A singularity-free new solution for anisotropic matter is also presented.
Analysis of the high resolution spectrum of the ν2 and ν5 absorption bands of methyl chloride
Authors: Morillon-Chapey M. , Guelachvili G. , Jensen Per
Published: October 2017

The infrared spectrum of methyl chloride CH3Cl between 1280 and 1650 cm−1 has been recorded at high resolution (0.005 cm−1). The Coriolis interactions between ν2(A1) and ν5(E) and between 2ν3(A1) and ν5 have been investigated through a least squares fit to the transitions observed for CH335Cl. Ten parameters for the three upper vibrational states and three interaction constants have been determined, reproducing the 1200 observed wavenumbers with a standard deviation of 0.002 cm−1. An accidental resonance of the type l(ΔK = 2, Δl = −1) between ν2 and ν5 was found to be present in the spectrum.
Le niveau de base du silane obtenu à partir de l'étude du spectre à transformée de Fourier de ν2 et ν4
Authors: Pierre G. , Valentin A. , Henry L.
Published: October 2017

We have recorded a vibration–rotation spectrum of 28SiH4 from 840 to 1040 cm−1 with a Fourier transform spectrometer operating with an apparatus-function width of 2 × 10−3 cm−1. An analysis of microwave transitions and 919 combination differences between two different ground state levels and an excited level belonging to the band ν2 or ν4 have been used to determine the value of the ground state constants as expressed in a sixth-order Hamiltonian development. The experimental spectrum needed was recorded with the Fourier transform spectrometer of the Laboratoire de Spectronomie Moléculaire de Paris. The experimental precision is about 0.0001 cm−1. The calculation reproduces these 919 differences with a standard deviation of 0.00019 cm−1.
Dynamics of quark-bag vibrations: validity of the adiabatic approximation
Authors: Nogami Y. , Tomio Lauro
Published: October 2017

In order to gain an insight into the nature of possible quark–bag vibrations, we consider a schematic "dynamical bag model" for hadrons. The model consists of a spherical bag with an ad hoc inertial mass and surface tension, and the quarks it contains. The bag and quarks are both treated nonrelativistically, and the Schrödinger equation for the coupled bag–quark system is solved. It is found that the adiabatic approximation, which is meant for a bag much heavier than the quark, describes the first excited state of the bag vibration quite well even if the masses of the bag and quark are comparable. This bag excitation simulates the Roper resonance in the nucleon sector. For a bag level which is nearly degenerate with a quark level (of the same parity, etc.) in the adiabatic approximation, the approximation naturally fails.
Temperature dependence of the energy gap in semiconductors
Authors: Manoogian A. , Woolley J. C.
Published: October 2017

It is shown that the equation ΔE = αT2/(T + β), which is commonly used to describe the temperature variation of energy gaps in semiconductors, is a second order approximation of the electron–phonon interaction term in the recently proposed equation ΔE = UTs + Vθ[coth (θ/2T) – 1]. The calculation shows that the parameters α and β of the approximate equation can describe the characteristics of semiconductors only if the relation [Formula: see text] holds, with the validity limited by the magnitude of the existing dilation effect. In this case it is found that β = θ/2 where θ is the effective Einstein vibrational frequency, in temperature units, of the phonon spectrum in the material. A comparison of the two equations when fitted to experimental data is presented and discussed.
The giant dipole resonance of mass-15 nuclei and the 12C(3He,γ0)15O and 11B(α,γ0)15N reactions
Authors: Bianco W. Del , Kajrys G. , Kim J. , Kundu S. , Landsberger S. , Lecomte R. , Monaro S.
Published: October 2017

The angular distributions of the 11B(α,γ0)15N and 12C(3He, γ0)15O reactions have been measured at several energies over the giant dipole resonance (GDR) of the two residual nuclei. The 90° yield curve of the 11B(α,γ0)15N reaction has been remeasured with improved energy resolution over the energy ranges Eα = 6.89 – 8.0 and 12.8 – 15 MeV. The γ-rays were detected by a 23-cm long × 23-cm diameter NaI(Tl) crystal spectrometer enclosed in a plastic scintillator anticoincidence shield. Spins and parities of the resonances observed in the yield curves were obtained; the structure previously observed in the yield curve of the 11B(α, γ0)15N reaction between Eα = 7 and 8 MeV has been resolved into two peaks.
Positron motion in metals. II. Models for data analysis
Authors: Hyodo T. , McMullen T. , Stewart A. T.
Published: October 2017

Two aspects of the momentum distribution function for positrons interacting with phonons and electrons in metals are studied. First, a simple approximation to the theoretical expression for the momentum distribution is found. It is used to clarify the meaning of the apparent mass in a Gaussian distribution introduced in the analysis of experimental data. Secondly, numerical evaluation of the theoretical momentum spectrum of the annihilating electron–positron pairs demonstrates the inadequacies of the Gaussian approximation. This leads to a new method of analysis of experimental data using the realistic distribution. This method allows one to obtain separately the positron quasiparticle mass and the positron–phonon coupling strength.
Spectroscopie d'électroionisation de HBr et DBr entre 11 et 25 eV
Authors: Marmet Paul , Nasrallah Hamid K.
Published: October 2017

Electroionization spectra of HBr and DBr are measured and analyzed between the ionization threshold and 25 eV. Several negative-ion states having configurations (4pσ) (4pπ)4 5s2, 5p2, and 4d2, associated with Rydberg states converging to the 2Σ+ limit, have been identified. Other structures result from the excitation of the inner 4sσ electron. Finally, data on DBr are used to confirm the interpretation.
Hydrogen and helium atoms in strong magnetic fields
Authors: Hansen T. O. , Østgaard E.
Published: October 2017

The behaviour of atoms in strong magnetic fields of the order of 106–1012 G is investigated, and ground-state energies of hydrogenlike and heliumlike atoms are calculated and compared with earlier results. For the hydrogen atom, we make a variational calculation for so-called hydrogenlike states, where we assume the solution in the direction of the field corresponds to the solution of a one-dimensional Schrödinger equation with a truncated Coulomb potential. For the helium atoms we also try a variational approach where the trial wave functions are products of single-particle "orbitals," which are mainly magnetic in their spatial form.Ground-state energies and ionization energies are tabulated for field strengths ranging from 106 to 1012 G. At 1012 G, for instance, the binding energy of a hydrogen atom is changed from −13.6 eV to approximately −150 eV, which is in reasonable agreement with other calculations. The corresponding result for the ground-state energy of a helium atom is a change from −78 eV to approximately −730 eV, also in fair agreement with other calculations. Ionization energies for the outer electron are found to be approximately 50 eV for H− atoms and 350 eV for He atoms in a magnetic field of 1012 G.
Hydrogenic atoms in one-plus-one dimensions
Authors: Capri A. Z. , Ferrari R.
Published: October 2017

We consider a Dirac particle in 1 + 1 dimensions interacting with an external Coulomb potential and prove that this potential produces no bound states at all.
Electromagnetic form factors of 3He and 3H and tensor algebra with computers
Authors: Bornais R. , Goulard B.
Published: October 2017

Computer-based tensor calculations are presented that make estimating of three-nucleon nuclei electromagnetic form factors much easier. Possible extensions are outlined.
Permutation symmetry and anomalous dimensions of four-field operators in theory
Authors: Lam C. S. , Walton M. A.
Published: October 2017

We calculate the anomalous dimension matrices of four-field operators in a [Formula: see text] theory to second order in the coupling constant. Using the simple Bose symmetry between the fields of the operators, we diagonalized the matrices in a novel way. Eigenvalues are obtained for even spins 2–10. The possible relation between this work and analogous QCD (quantum chromodynamics) calculations is discussed.
Derivation of muon range spectrum under rock from the recent primary spectrum
Authors: Pal Pratibha , Bhattacharyya D. P.
Published: October 2017

The muon range spectra under Mont Blanc Tunnel and Kolar Gold Field rocks have been calculated from the recently measured primary cosmic ray spectrum. The scaling hypothesis of Feynman has been used for the calculation of pion and kaon spectra in the atmosphere. The meson atmospheric diffusion equation has been solved by following the method of Bugaev et al. The derived muon energy spectrum has been found to be in good agreement with the measured data of the Kiel, Durham, DEIS, and Moscow University groups. The calculated muon energy spectra at large polar angles have been compared with the different experimental results. The integral muon spectrum up to 20 TeV supports the MARS burst data favourably. Using the procedure of Kobayakawa, the muon energy loss in rock due to ionization, pair production, and bremsstrahlung and nuclear interactions from Bezrukov and Bugaev, we have constructed the range–energy relation in Mont Blanc and Kolar Gold Field rocks. The estimated range spectra have been corrected for range fluctuations and have been compared with the Mont Blanc Tunnel data of Castagnoli et al., Bergamasco et al., and Sheldon et al. and the Kolar Gold Field data compilation by Krishnaswamy et al.
Clebsch–Gordan decomposition for transitive representations
Authors: Lulek B. , Lulek T. , Chatterjee R. , Biel J.
Published: October 2017

The method of evaluation of Clebsch–Gordan coefficients to calculate the direct product of transitive representations for a finite group is developed. This procedure is based on the Mackey theorem and on the canonical realization of transitive representations. It is shown that the Clebsch–Gordan decomposition is associated with a natural interpretation of an orbit of a resultant transitive representation and it is analogous to a fibre bundle with the fibration being determined by constituent transitive representations.
Uniaxial stress and magnetic field dependence of the In- and Tl-related isoelectronic bound excitons in Si
Authors: Watkins S. P. , Thewalt M. L. W.
Published: October 2017

We present the results of uniaxial stress and Zeeman splitting measurements on the photoluminescence spectra of the unique isoelectronic bound excitons found in In- and Tl-doped Si, which are known to exist in two very different configurations. Our results indicate that these two configurations correspond to the two known classes of isoelectronic bound excitons, which differ in the sign of their internal strain field. We also show that the results are not in agreement with previous suggestions that these isoelectronic bound exciton transitions have half-integer angular momenta in both the initial and final states.
Electron transmission through a potential barrier in the presence of an electromagnetic field: unitary transformation method
Authors: Mayer I. L. , Miranda L. C. M. , Galvāo R. M. O.
Published: October 2017

Using the unitary transformation method, we discuss the influence of an intense high-frequency electromagnetic field on the transmission probability of an electron through a one-dimensional square barrier. It is shown that the transmission probability increases exponentially with increasing field strength.
The influence of temperature and pressure on the optical spectrum of monoclinic tetrathiafulvalene crystals
Authors: Baillargeon Pierre , Roubi Larbi , Carlone Cosmo , Truong Kim Doan
Published: October 2017

The absorption spectrum of monoclinic tetrathiafulvalene has been obtained from 15 400 to 28 600 cm−1 at 0 bar for two temperatures: 84 and 298 K. The change with temperature of the low-energy leading edge (the Ag → Bu transition) is −1.0 ± 0.5 cm−1∙K−1. The spectrum was also obtained at 298 K as a function of pressure up to 6.6 × 104 bar. The change with pressure is −40 ± 5 cm−1∙103 bar−1. The total temperature dependence consists of the extrinsic contribution, which is a measure of the electron–phonon interaction and which we estimate to be −2.2 cm−1∙K−1, and the intrinsic contribution, which is a measure of the volume dilatation and which we estimate to be + 1.2 cm−1∙K−1.
Second-order treatment of the influence of space charge and external fields on rotationally symmetric finite-emittance relativistic beams of charged particles
Authors: Bosi Giulio
Published: October 2017

The present paper reports a relativistic treatment of space-charge effects on rotationally symmetric beams of charged particles under the influence of an external electromagnetic field. The general form of a stationary distribution describing a homogeneous, monokinetic beam is suggested, and the details of a suitable generalization of the Kapchinskij–Vladimirskij distribution are fully developed. It is shown that if second-order terms, which mainly affect the longitudinal motion, are retained, the given distribution actually provides a parabolic charge density throughout a beam cross section while the longitudinal current density remains uniform, as is usually assumed. The relativistic version of the envelope equation, including the magnetic field, is also calculated and its classical limit is compared with an available equation applicable to a beam under the influence of merely an electric field. Emittance-dependent discrepancies, related to the longitudinal effects of the space charge, are detected. The standard geometry of a rotationally symmetric Pierce gun is finally revised to allow for the addition of an external magnetic field.
Infrared absorption by localized electrons in solid deuterium
Authors: Bose S. K. , Poll J. D.
Published: October 2017

A broad absorption in the spectral region 4000–7500 cm−1 has been observed in tritiated as well as proton-irradiated samples of solid deuterium. To explain this absorption we investigate two different types of localized electronic states in the solid. It is shown that the absorption can be interpreted as being due to the lowest energy bound-state transitions of electrons localized in nonspherical cavities of two different average radii. The localization is assumed to be initiated by vacancies. The shape of the absorption line is calculated by estimating the cavity size and the frequency of the breathing-mode oscillation of these cavities.
Cross sections for quenching of Pb 6p7s3P1 atoms by collisions with CH4, CO, and CO2 molecules
Authors: Giers D. H. , Atkinson J. B. , Krause L.
Published: October 2017

Pb vapor mixed with a buffer gas was irradiated with pulses of laser light so as to populate the [Formula: see text] state, whose radiative and collisional decay was monitored by the method of time-resolved fluorescence spectroscopy. The variation of the measured decay constants with buffer-gas pressures yielded the total depopulation (quenching) cross sections Q = 3.32 ± 0.25, 25.6 ± 2.2, and 84.1 ± 8.4 Å2 for collisions with CH4, CO, and CO2, respectively.
H218O: The (030), (110), and (011) interacting states. Line positions and intensities for the 3ν2, ν1 + ν2, and ν2 + ν3 bands
Authors: Chevillard J.-P. , Mandin J.-Y. , Flaud J.-M. , Camy-Peyret C.
Published: October 2017

The spectrum of oxygen-18 enriched water vapor was recorded between 4400 and 6100 cm−1 with the aid of a Fourier transform spectrometer. Its analysis allowed the determination of 60 energy levels of the (030) vibrational state of H218O and improvements in the knowledge of the energy levels belonging to the (110) and (011) vibrational states of this molecule. A fit of 330 rotational levels of the (030), (110), and (011) states was performed using 54 effective constants and taking into account the Coriolis-type and Fermi-type interactions. Moreover, 853 line intensities belonging to the 3ν2, ν1 + ν2, and ν2 + ν3 bands were measured. The constants involved in the rotational expansion of the transformed transition moment operator corresponding to these bands were determined through a fit of these line intensities. The constants obtained were then used to compute the whole spectrum of the 3ν2, ν1 + ν2, and ν2 + ν3 bands of H218O. This spectrum should be of interest for atmospheric studies.
A note on time-reversal symmetry
Authors: Girard Ralph , Kröger Helmut
Published: October 2017

Model-independent results on time-reversal symmetry are presented. It is shown that, for any Hermitian, time-reversal noninvariant Hamiltonian, one can find invariant cross sections. The sensitivity of polarization–asymmetry and detailed balance is studied. In first-order perturbation theory, only polarization–asymmetry is found to be a sensitive test.
Note on capillary waves in the gradient theory of interfaces
Authors: Sobrino Luis De
Published: October 2017

The calculation of the dispersion relation for capillary waves in the gradient theory of interfaces has been generalized to the case in which the gradient term in the free energy depends on temperature. The dispersion relation is found to agree with the classical theory.
Électroionisation des alcalins : mise au point d'un nouvel appareil de mesure
Authors: Proulx M. , Marmet P.
Published: October 2017

The purpose of this paper is to describe a new instrument capable of measuring the electroionization efficiency curves of the alkali metals. In particular, a conceptually new ion source is presented whose main characteristic is the sequential application of pulses to certain electrodes, which allows the ionization of the atoms and the injection of the ions into a mass filter to occur at different times. The performance of the apparatus is discussed, and preliminary results are presented.
Principle-of-minimal-sensitivity-corrected quantities in heavy quarkonia
Authors: Dentamaro Anthony V. , Goldstein Gary R.
Published: October 2017

Stevenson's principle of minimal sensitivity is used in renormalizing radiative corrections to hyperfine splittings, leptonic and hadronic decay widths, and electric-dipole transition rates. Numerical values for these quantities are presented for the charmonium and bottomonium systems, enlisting several nonrelativistic phenomenological potential models to determine the best fit to the experimental data. It is shown that good results may be obtained within a single model in which the value of ΛQCD is calculated and kept constant for all predictions within that model.