bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetogasdynamic Aligned Flows with Finite Electric Conductivity
Authors: Chandna O. P. , Holmes R. W.
Published: April 2011

It is established that the steady, axially symmetric flow of a compressible, electrically conducting fluid with finite conductivity has either zero charge density or an irrotational magnetic field. Some properties and solutions of these flows are studied for plane and axially symmetric flows.
Band Structure in 21Ne
Authors: Pilt A. A. , Spear R. H. , Elliott R. V. , Kelly D. T. , Kuehner J. A. , Ewan G. T. , Rolfs C.
Published: April 2011

The 18O(α,nγ) reaction at α-particle bombarding energies of 5.2 and 6.1 MeV was used to study the levels in 21Ne below 4 MeV excitation. A combination of γ-ray angular distribution and linear polarization measurements using a single crystal Ge(Li) polarimeter confirmed the spins and parities of the 1747 and 2867 keV states to be 7/2+ and 9/2+ respectively and assigned negative parity to the J = 3/2 level at 3663 keV and J = 5/2 level at 3886 keV. The state at 3735 keV was shown to have Jπ = 5/2+. Values of the multipole mixing ratios of γ rays deexciting these states were found to be consistent with previous measurements. A γ–γ coincidence experiment revealed the existence of a (1.8 ± 0.7)% decay branch of the 3886 keV level to the 2790 keV level. The results are interpreted in terms of the Nilsson model. Evidence for the existence of a Kπ = 1/2− band based on a hole in the 1p1/2 shell is given.
Théorie Exacte de la Distribution de la Somme des Photoélectrons Emis en L Points
Authors: Bures Jacques , Delisle Claude , Zardecki Andrzej
Published: April 2011

The statistical behavior of photoelectrons emitted at L points of a photocathode in partially coherent Gaussian light is considered. The exact formula for the cumulants and the factorial moment generating function is derived. An exact expression for the photocount distribution and for the factorial moments is obtained in the case when the detection time is much smaller than the coherence time. Two cases of interest which were treated earlier by the same authors are also considered. In particular, the case of two points of detection is of special interest because a physical meaning can be given to the difference of the normalized eigenvalues. Finally, both the exact and approximate theories are compared with the experimental photocount distribution for four different geometrical arrangements.
Positron Correlation Energy in Metals
Authors: Bergersen B. , Carbotte J. P.
Published: April 2011

The positron correlation energy in an electron gas is calculated in the metallic density region using the random phase dielectric constant. It is found that the positron–plasmon interaction is much more important for the correlation energy than for the annihilation rate, and that the plasmon contribution to the energy is actually larger than the particle–hole contribution. Calculations using the Singwi et al. dielectric constant give essentially the same results as the RPA. It is argued that the ladder approximation need not represent an improvement over linear response theory when computing the correlation energy.
Some Observations on Arc Potentials in Hydrogen Thyratron Pulse Discharges
Authors: Armstrong R. J.
Published: April 2011

The arc voltage in high power hydrogen thyratrons has been measured, under a variety of pulse and DC conditions. The valve is found to be higher under pulse conditions than under DC conditions. An explanation, similar to that invoked by Sugawara and Gregory in a different situation, is found to give some agreement with the experimental results. This explanation depends on the relaxation properties of the electrons and ions in an electrical discharge or plasma.
Application of Moffat's Model to η → 3π and K → 3π Decays
Authors: Smith Donald , Picciotto Charles
Published: April 2011

Moffat's model for meson–meson scattering, satisfying the Mandelstam representation, crossing symmetry, and Regge behavior, is applied to η → 3π and K → 3π decays. It is found that agreement with the data is excellent when the model is used with Lovelace's trajectory, but not as good with Moffat's trajectory. The model is also applied to the process [Formula: see text], and fair agreement is found in the low energy region; however, since the model is unitary only at low energies, no strong conclusions can be reached in this case.
Line Shape of C Bands in Alkali Halide Phosphors by the Method of Moments
Authors: Sati R. , Wang S. , Inoue M.
Published: April 2011

We have derived the optical absorption line shape for C bands in alkali halide phosphors by the method of moments. The dynamic Jahn–Teller interaction is considered in the excited T1u electronic states. This interaction is taken to be linear in the lattice displacements. The obtained line shape exhibits asymmetric triplet structure even in the linear electron–lattice interaction. The use of the quasi-classical approach (i.e. the use of the adiabatic approximation and Franck–Condon principle) for electronic transition to orbitally degenerate states is discussed by comparing the line shapes obtained in this approach with those obtained by the method of moments.
Analytic method for the solution of the one-group, integral transport equation for a homogeneous sphere
Authors: Milgram Michael S.
Published: April 2011

The one-group integral transport equation for the spatial distribution of the flux density in a homogeneous critical sphere is reduced to a standard matrix eigenvalue problem, and the matrices are small. The elements of the matrix are simple functions, the eigenvalues correspond to critical values of the number of secondaries/collision, and the eigenvectors represent the coefficients of the Taylor's series of the flux expanded about the centre of the sphere. Analytic approximations and numerical results are cited and the connection with classical diffusion theory is developed.
Path-dependent formulation of an extended Yang–Mills system
Authors: McKeon Gerry
Published: April 2011

The standard Yang–Mills formalism is extended to include a self interaction for the vector field in a manner analogous to the extension of ordinary electrodynamics to include dyons. Mandel-stam's path-dependent formalism is used to study this system.
Off-shell effects in (d,p) stripping reactions
Authors: Pantis George
Published: April 2011

The off-shell behavior of the differential cross section in (d,p) reactions is described within the R-matrix theory assuming a direct 'stripping into continuum' process. In particular, with the inclusion of the off-shell background term and its interference, some levels in the reaction 15N(d,p)16N (unbound) are interpreted. Other interesting consequences of this description are also discussed.
Predicted branching ratio for π−d → π0nn at rest
Authors: Beder Douglas
Published: April 2011

The branching ratio for rest capture π−d → π0nn is calculated using the impulse approximation for π0nn and data for other rates. Detailed discussion is devoted to corrections to the simplest approximation, and to relevant details of the deuteron description. The result for the predicted branching ratio is (1.46 ± 0.25) × 10−4.
Deuterium quadrupole splittings and hydrocarbon chain ordering in model membranes
Authors: Dong Ronald Y.
Published: April 2011

It is pointed out that asymmetry in the electric field gradient is required for a correct determination of the order parameter tensor. Expressions for the quadrupole splittings of deuteriomethylene and deuteriomethyl groups are given without assuming axial symmetry in the electric field gradient and in the degree of orientation.
SCIMP—A scanning interferometric multiplex photometer
Authors: Shepherd G. G. , Deans A. J. , Neo Y. P.
Published: April 2011

An interference filter photometer concept is described in which equally-spaced spectral elements of equal width are generated. The method takes advantage of the wavelength shift of off-axis radiation transmitted by the filter, and is accomplished by the use of masks in the location of the field stop. This technique lends itself to multiplexing, using Fourier or Hadamard coding, but a direct spectral configuration is also possible. The advantages of the concept and a comparative analysis of signal-to-noise ratio are described. The technique has been employed in ground based airglow studies, airborne remote sensing, and rocket measurements of airglow and aurora.
The pressure and temperature consistent Lennard-Jones liquid
Authors: Hall Donald S. , Conkie W. R. , Hutchinson P.
Published: April 2011

An approximate theory for the radial distribution function of a homogeneous system is presented that ensures consistency between the pressure and compressibility equations, and that the Helmholtz free energy has a unique value. The theory is applied to the fourth virial coefficient of a Lennard-Jones fluid in order to investigate the importance of the latter requirement.It is found that the resulting fourth virial coefficient shows a substantial improvement over that of theories that do not give a unique free energy.
Valence band density of states and X-ray photoelectron spectrum of GaS
Authors: Balzarotti A. , Girlanda R. , Grasso V. , Doni E. , Antonangeli F. , Piacentini M.
Published: April 2011

The valence band density of states of GaS has been investigated by X-ray photoelectron spectroscopy and the spectrum has been interpreted on the basis of a single layer tight-binding calculation. Our two-dimensional approximation seems largely appropriate to reproduce the main experimental features of the valence band density of states of GaS, as previously found in the case of InSe. It can also explain to some extent the fine structure in the ultraviolet photoemission spectra recently measured with the synchroton radiation.
Electrical resistivity with spin–orbit scattering
Authors: Huberman M. , Ballentine L. E.
Published: April 2011

The electrical resistivity is obtained from a transport equation that includes the spin density matrix. The usual description in terms of spin-up and spin-down electrons is valid if the spin density matrix is diagonal; however, this cannot be true simultaneously for all electron momentum states. Quantitative results are given for liquid Pb and Bi.
A calculation of the electron–electron scattering contribution to the electrical resistivity of copper
Authors: Black J. E.
Published: April 2011

The contribution of electron–electron scattering to the electrical resistivity of copper has been calculated. Parts of the Fermi surface on which the initial and final electronic states contribute most heavily to the resistivity have also been determined. The calculations are based on two plane-wave states for the electrons and a Thomas–Fermi screened Coulomb interaction between electrons. The Fermi surface is approximated with the eight-cone model used in noble metals. The results of the calculations are presented here and compared with calculations and experimental data of other authors.
Perturbation version of the Percus–Yevick equation: the square-well potential
Authors: Rao R. V. Gopala , Joarder R. N.
Published: April 2011

A perturbation treatment of the direct correlation function for the attractive forces in a fluid with the hard sphere reference system is given and the static structure factors are calculated in the framework of a square-well potential. The compressibility equation of state obtained analytically predicts the pressure very well for a relatively small perturbation potential. All these calculations are compared with Monte Carlo and molecular dynamics results of other workers for this system.
Stark spectroscopy with the CO laser: Lamb dip spectra of H217O and H218O in the ν2 fundamental band
Authors: Johns J. W. C. , McKellar A. R. W.
Published: April 2011

Saturated absorption spectra of four different transitions in the ν2 fundamental bands of H217O and H218O have been observed using the technique of intracavity CO laser Stark spectroscopy. The analysis of these spectra yields a direct measurement of the dipole moment change between the ground vibrational state and the ν2 = 1 state of H217O, as well as the zero-field frequencies for the observed transitions. A collision-induced centre dip ('crossover resonance') which occurs in one spectrum is formed in a four-level system that is probably the most nearly isolated of any yet observed.
Effect of second neighbour interaction on the frequencies of defect-clusters in a linear chain
Authors: Srivastava K. P. , Ojha S. P.
Published: April 2011

Results of computer calculations on frequencies of defect clusters of identical atoms embedded in a linear chain with second neighbour interaction have been presented. Effort has been made to explain the contradictory results of Martin and those of Brouers and Deltour on the basis of our results.
The radial density function and expectation values for ions
Authors: Boyd Russell J.
Published: April 2011

Analytical expansions for the radial density function D(r) and expectation values of rn, −2 ≤ n ≤ 5, as calculated within the Hartree–Fock approximation, are reported for a large number of ions of the first 54 elements.
A shell model of the cobalt isotopes
Authors: Taylor T. , Summers-Gill R. G.
Published: April 2011

Binding energies, excitation energies, and single nucleon transfer spectroscopic factors of the 55 ≤ A ≤ 60 cobalt isotopes have been calculated in a 1f–2p shell configuration space assuming a 56Ni core. Single-particle energies were determined empirically and two-body matrix elements were computed with the modified surface delta interaction (MSDI). The observed properties of the low-lying states are reasonably well reproduced but some low-spin states observed above 1.3 MeV are outside the model space. The theory predicts quasi-rotational bands of high-spin states in both odd- and even-A cobalt isotopes.
Photoproduction of gravitons in a static magnetic dipole field due to currents
Authors: Papini G. , Valluri S. R.
Published: April 2011

The cross section for the photoproduction of gravitons in magnetic dipole fields which are due to steady currents is calculated. The approach and the results are compared with the previously studied case in which no currents exist and the potential is represented by a scalar. The calculations in both cases are completely covariant and electromagnetically gauge invariant. The radiative corrections to order [Formula: see text] and [Formula: see text] in the nonrelativistic and relativistic limits are also calculated for dipole and Coulomb fields, respectively. Their evaluation is particularly simple in the transverse traceless gauge for the gravitational field.
Antiferromagnetism in amorphous alloys containing rare-earth atoms. II. Monte Carlo studies
Authors: Sung S. H. , Harris R. , Zuckermann M. J.
Published: April 2011

The model of Harris, Plischke, and Zuckermann for random magnetic anisotropy in amorphous alloys is examined for the case of antiferromagnetic exchange coupling using Monte Carlo techniques. Initial magnetization curves, hysteresis loops, and coercive fields are obtained and compared with the results of the molecular field approach of Callen, Liu, and Cullen. The external magnetic field for spin-flip transitions is obtained and is discussed in relation to previous work by Ferrer and Zuckermann and Coqblin and Bhattacharjee. The results are discussed in the light of recent experimental work.
Thermal stability of some radiation damage products in X-irradiated NaClO3
Authors: Sivasankar V. S. , Whippey P. W.
Published: April 2011

Single crystals of sodium chlorate have been exposed to X-rays, at 77 K. Thermoluminescence glow curves of the irradiated crystals have been recorded from 77 to 400 K. Optical absorption spectra and electron spin resonance spectra of the crystals subjected to radiation damage have also been recorded as a function of radiation dose, and at different stages of thermal annealing between 77 and 400 K. Using the optical and ESR data, the glow peaks at 173, 185, and 249 K have been identified as due to O2− in the vicinity of ClO3, ClO3, itself, and O2− adjacent to ClO2, respectively. The trapping parameters for these centers have been determined.
Assignment of Jπ = 1− for the 5.048 MeV level of 16N
Authors: Pantis G. , Sprung D. W. L.
Published: April 2011

A study of the 15N(d,p) reaction leading to the 2.732 MeV state in 16N yields an unambiguous assignment of Jπ = 1− for that state.
Relativistic oscillator strengths for np2 → np(n + 1)s transition array of SnI and PbI spectra in jj and intermediate coupling
Authors: Migdałek J.
Published: April 2011

The relativistic oscillator strengths for the np2 → np(n + 1)s transition array as well as the lifetimes of levels of the np(n + 1)s configuration in SnI and PbI spectra were calculated in jj and intermediate coupling. The relativistic radial integrals were computed employing the wave functions obtained by a semiempirical approach which allowed for exchange effects. The results obtained are compared with existing experimental and theoretical data. The significance of intermediate coupling for oscillator strengths computations is discussed. The agreement with experiment is for the present semiempirical results generally better (particularly for the PbI spectrum) than for oscillator strength deduced from 'Optimized Hartree–Fock–Slater' transition probabilities, which were published previously.
Etude comparée des caractéristiques d'un laser à double décharge et d'un laser à photopréionisation à pression supraatmosphérique
Authors: Blanchard Michel , Tremblay Réal , Cormier Maurice , Beaulieu R.
Published: April 2011

A photopreionization CO2 laser and a Laflamme-type double-discharge CO2 laser have been studied up to a pressure of 10 atm. The comparison between the two systems for identical operating conditions allows us to better characterize both lasers with respect to each other. Many experimental results are given.
Vents neutres dans la région F2
Authors: Clairemidi J.
Published: April 2011

The Navier–Stokes equations are solved by introducing a statistical model of density and a distinct temperature model. The computations have been made for equinoctial conditions at a height of 300 km and at different latitudes. The non-linear terms of inertia are included. They slightly reduce the amplitude of the speed, but their influence can be neglected, particularly during the day.The results are presented in the form of a global wind pattern. The most important features are: the existence of transequatorial winds at night, the asymmetrical structure of the wind pattern, and the agreement of the computed velocities with observations.
Electrical transport and band structure of GaAs
Authors: Lee H. J. , Basinski J. , Juravel L. Y. , Woolley J. C.
Published: April 2011

Measurements of electrical conductivity σ and Hall coefficient RH have been made as a function of temperature in the range room to 500 °C on single crystal n-type tellurium doped samples of GaAs with carrier concentrations in the range 7.9 × 1021 to 4.7 × 1024/m3. Theoretical calculations of σ and RH have been made on a three band (Γ, L, X) model using the method of Fletcher and Butcher and the resulting values fitted to the experimental data by using the temperature coefficients of the band energy differences and various deformation potentials and band coupling coefficients as adjustable parameters. The results confirm the band ordering proposed by Aspnes but give slightly different temperature coefficient values. Values are given for the deformation potentials and band coupling coefficients and in particular the deformation potential of the Γ band is found to be 16.0 ± 0.5 eV.
Possible ferromagnetism of a free-electron pair
Authors: Olszewski S.
Published: April 2011

It is pointed out that the relation E(ΦA) < E(ΦS) holds for a free-electron pair within a potential box on condition that the assumptions of (i) the continuity of wave functions and their derivatives, (ii) very thin potential box, and (iii) weak Coulomb interaction between the electrons, are satisfied; E(ΦA) denotes the lowest energy of the triplet state of the pair with which a net spin magnetic moment may be associated E(ΦS) is the lowest energy of the nonmagnetic singlet state of the pair. Mutual position of E(ΦA) and E(ΦS) cannot be predicted a priori, as wave functions ΦA and ΦS fulfill different boundary conditions.
The determination of spin arrangements in magnetic materials by means of Mössbauer spectroscopy using polarized γ-rays
Authors: Daniels J. M.
Published: April 2011

In many magnetic materials it is a good approximation to say that the nuclei of magnetic atoms are subject to axial magnetic fields, and one topic of investigation is to determine the distribution in orientation of these axes. Formulae are given which enable the intensities of 57Fe Mössbauer lines to be calculated in terms of the polarization of the incident γ-rays and parameters which characterize the distribution of the axes of the internal magnetic fields acting on the 57Fe nuclei in a magnetically ordered absorber.
Conformal transformations in spinor space–time
Authors: Hong Nguyen Thi
Published: April 2011

In our previous works a method of realizing the bilinear spinor representation of space–time has been suggested, in which the usual translation transformation can be established and therefore the space–time symmetry Poincaré group can remain. In this note we are extending the formalism to involve the conformal transformations.
Fluorescence decay rates of X2UO2Cl4, X = Cs, Rb, and K
Authors: Leung A. F. , Tsang K. K.
Published: April 2011

Fluorescence of alkali uranyl chloride single crystals originates from close-lying doublet levels. The fluorescence decay contains two different decay rates. One rate describes the relaxations of the pure crystal, whereas the other is related to relaxations of impurities or defects in the crystal. The temperature dependence of the two decay rates has been measured. Moreover, it can be explained by assuming that the fluorescent doublet is always in thermal equilibrium with a higher electronic level Ex which has a fast relaxation time. Comparison between measurement and theory of the temperature dependence of the decay rates yields the energy separation ΔE between the fluorescent doublet and Ex. Furthermore, ΔE can be correlated with other spectroscopic measurements.
New asymptotic expression for the average lifetime of hydrogenic levels
Authors: Millette P. A. , Varshni Y. P.
Published: April 2011

A new asymptotic approximation for the average lifetime of hydrogenic levels is developed and is shown to be much better than the one suggested by Bethe and Salpeter.
Absorption spectrum of the P18O molecule: 2Σ and 2Δ–X2Π transitions. Perturbation effects on the intensity of lines in the E2Δ–X2Π transition
Authors: Prudhomme J. C. , Ngo T. A. , Coquart B.
Published: April 2011

This paper is a survey of the 2Σ and 2Δ–X2Π absorption transitions of the P18O molecule in the region 1800–2500 Å; it gives some new details on the C2Σ−, F2Σ+, and G2Σ+ states; particularly it points out the electronic homogeneous interactions between the E2Δ Rydberg state and the C′2Δ valence state and shows that the perturbations rather than predissociations are responsible for the main intensity anomalies and gaps previously observed in the structure of the E2Δ–X2Π emission bands.
An experimental investigation of small angle photon elastic scattering
Authors: Ramanathan N. , Kennett T. J. , Prestwich W. V.
Published: April 2011

The differential cross sections for photon elastic scattering have been determined for targets of Cu, Cd, Ta, and Pb, at angles of 2.4, 3.5, 5.1., 6.0, 8.0, and 10.0° and incident energies of 244.7, 344.3, 443.9, 778.9, 964.0, 1085.8, 1112.0, 1274.2, and 1408.0 keV. The data indicate that presently calculated form factors may be too large, and suggest that intermediate bound states may influence the scattering amplitude.
Helicon–phonon interaction for potassium
Authors: Idiculla Roschen , Viswanathan K. S.
Published: April 2011

The paper deals with a numerical study of helicon–phonon interaction for potassium for magnetic fields in the range 0.2 × 105 to 4.0 × 105 G. The dispersion equation for helicon–phonon interaction for propagation of a wave parallel to the direction of the magnetic field in the xy plane has been derived explicitly and the nature of variation of the four different modes with the magnetic field has been studied numerically. The numerical data suggest that at the resonance region, mode conversion takes place and the waves are of a hybrid nature. The sections of the group velocity surface by the xy plane are nearly circular for the helicon. The eigenvectors of the four different modes have been evaluated numerically for different angles of propagation as well as for different magnetic fields and these would enable one to specify the nature of any mode travelling with a particular velocity, whether it is a helicon, longitudinal, shear, or a hybrid mode.
Levels in 148Tb excited by the (6,7Li,xn) and (10B,xn) reactions
Authors: Singhal N. C. , Johns M. W.
Published: April 2011

High spin slates in 148Tb have been excited by means of 144Sm(6Li,2n), 144Sm(7Li,3n), and 142Nd(10B,4n) reactions and studied by γ-ray and electron measurements. Gamma-ray singles, excitation functions, angular distributions, internal conversion coefficients, and γ–γ coincidence measurements have been made. A seven-fold gamma–gamma cascade feeding the 9+ isomeric state in 148Tb and originating in a level 4137 keV above that state is strongly excited. The spin and parity assignments are made on the basis of angular distribution and internal conversion coefficients. On the basis of these measurements, the 1006 keV transition is E3 in character; the half-life of the 1006 keV (12−) level is established to be 25 ± 2 ns.These experiments also confirm the existence of a number of high spin states in 148Gd seen by earlier workers.
Optical spectra in WSe2
Authors: Anedda A. , Fortin E. , Raga F.
Published: April 2011

Optical spectra in the 1.5 to 3.2 eV range are studied in the layered compound WSe2 by wavelength and temperature-modulated reflectivity, as well as by modulated photovoltaic effect from 4.1 to 300 K. The selection rules for optical transitions in WSe2 are deduced, and the spectra are interpreted with the help of the known band structure of the isomorphous compound MoS2.The parameters of the A exciton series are determined, and the temperature shift of the main spectral structures is studied.
Sea level muon spectrum derived from the primary nucleon spectrum using the Cocconi–Koester–Perkins model
Authors: Chakrabarti A. K. , Das A. K. , De A. K.
Published: April 2011

In a recent paper Sarkar, Bhattacharyya, and Basu have derived the sea level muon energy spectrum from the measured nucleon spectrum of Ryan, Ormes, and Balasubrahmanyan using the Cocconi–Koester–Perkins model. They have found good agreement between this muon spectrum and the precisely measured spectrum of Ayre, Baxendale, Hume, Nandi, Thompson, and Whalley. In this report a critical analysis of the paper has been made and it is found that there are some obvious mistakes both in the formulation and in the calculation. The corrected results do not agree with the Ayre et al. spectrum. The unjustified values of some of the parameters used in their work are discussed.
The Langmuir probe measurement of flow velocity in a flame plasma
Authors: MacLatchy C. S. , Didsbury R.
Published: April 2011

A method of measuring the flow velocity in a flame or other collision dominated plasma is described. It is based on the velocity characteristic of a Langmuir probe which is swept through the plasma. The probes were operated in the sheath-convection régime and exhibited a systematic variation between thin and thick sheath behavior which was attributed to an expanding sheath as the plasma–probe conditions were varied.
An analysis of steam flow in a chip refiner
Authors: Press M. , Arrott A. S.
Published: April 2011

A mathematical analysis is made for the steam flow in a disc refiner, used in the manufacture of wood pulp. The appropriateness of several mathematical models is deduced from the analysis. The experimentally determined pressure variation through the refiner serves as input data. If one assumes that the heat is uniformly developed, the observed pressure profile would indicate that the refiner plates are not rigid. If one assumes that the plates are rigid, the observed pressure profile would indicate a recondensation of steam in the outer part of the refiner. The calculations illustrate the utility of deducing aspects of the behavior of the refiner from the measured pressure profile.
High resolution laser Stark and infrared–radiofrequency double resonance spectroscopy of H2O at 6 μm
Authors: Herman M. , Johns J. W. C. , McKellar A. R. W.
Published: April 2011

Laser Stark spectra have been observed in the (020) ← (010) hot band of H216O. A near coincidence between the 15–14 P(11) line of the 13C18O laser at 1677.228 cm−1 and the 606 ← 515 rovibrational transition of H2O as analyzed with the result: [Formula: see text]. Using the same laser line, an infrared–radiofrequency double resonance signal arising from the 422–515 transition within the (010) vibrational state was measured to be: 2159.98 ± 0.3 MHz.
A note on the solvability of simultaneous Wiener–Hopf equations
Authors: Hurd R. A.
Published: April 2011

Sufficient conditions are given for the solvability of simultaneous Wiener–Hopf equations by means of the Wiener–Hopf–Hilbert technique, for the case when the kernel matrix of the system has the special form appropriate to half-plane boundary value problems.
Structure and form factor models in the mass three system
Authors: Bevelacqua J. J.
Published: April 2011

The A = 3 system is studied within the framework of the generalized R-matrix method of Lane and Robson. Although the rate of convergence is slow, it is improved with the inclusion of nucleon + 2H channel functions. By employing these functions and a model space truncation procedure, converged binding energy estimates are obtained in model spaces which are smaller than those normally utilized. This model also leads to wave functions which are similar to those predicted in other A = 3 calculations. In addition, model form factors can be derived from this bound state information and applied to the 2H(d,n)3He and 2H(d,p)3H reactions. This procedure leads to cross sections which have a normalization in agreement with the data.
Rotational analysis of the 6480 Å absorption of NO2
Authors: Brand J. C. D. , Cross K. J. , Hoy A. R.
Published: April 2011

About 300 rotational transitions in the 6480 Å region in the visible absorption of NO2 gas have been assigned by laser-excited fluorescence. A majority of the stronger transitions belong to the K = 0 and K = 1 subbands of a vibronic band, T0 = 15 434.9 cm−1, whose upper state is predominantly an a1, vibrational level of the electronic 2B2 basis state. Other groups of relatively weaker lines form (i) a severely-perturbed K = 2 subband attributed to the same series as the K = 0 and 1 subbands; (ii) a well-developed though relatively weak K = 3 subband assigned to a hybrid level of mainly 2A1, character, the transition to this level being induced by vibronic coupling; and (iii) a K = 6 subband assigned to a parent (i.e., 2B2 basis) vibrational level different from that identified at 15 435 cm−1. The spectrum in this region abundantly illustrates the irregularities, 'extra' lines, resonance crossings, and erratic spin splitting now recognized as widespread in the NO2 visible absorption. Rotational constants are not well defined and vary considerably from one subband to another: large pseudo-centrifugal distortion constants are attributed to higher-order effects of the vibronic coupling. Franck–Condon analysis of the intensity distribution in fluorescence leads to a tentative vibrational assignment of 1 60 for the stale at 15 435 cm−1.
Decay of 122In
Authors: Cheung H. C. , Huang H. , Lee J. K. P.
Published: April 2011

We have studied the decay of 122In using two different types of sources: an isotopically separated source and another produced via 124Sn(d,α) reaction. Two isomers with similar half-lives were established: one decaying with 10.8 ± 0.4 s half-life, having Jπ of (8+), and the other, 10.3 ± 0.6 s half-life with Jπ of (3+, 4+, 5+). Separate decay schemes were proposed. Results are compared to a BCS calculation.
Density expansion of the correlation function of a hard sphere gas
Authors: Blair D. G. , Pope N. K. , Ranganathan S.
Published: April 2011

Using the grand canonical ensemble, the classical Van Hove correlation function G(r, t) is expanded in a power series in density. The zero density limit is the ideal gas result. We have derived, for a classical gas of hard spheres, exact expressions for [Formula: see text], the zero density derivative of the correlation function, and its Fourier transforms. These involve only two particle dynamics. The first two terms in the density expansions provide representation of the correlation functions for appropriate ranges of density and correlation function arguments. We also show that the same result can be obtained from generalized kinetic equations. To this order in density, the moment relations and the time derivatives of I(q, t) at t = 0+ are satisfied. Numerical results are compared with those of Mazenko, Wei, and Yip and with those of the Boltzmann equation and they show the expected behavior.
On the statistical mechanical interpretation of the translational energy dependence of rate processes
Authors: Shizgal B. , Fitzpatrick J. M.
Published: April 2011

The rate coefficient for the rates of binary gas phase collision processes is expressed as an integral over the relative translational energy of the particles involved in a collision and as an integral over the energy of one of the particles. It is found that these representations of the rate coefficient provide two very different conceptual pictures of the translational energy dependence of rate processes. For systems with a disparate mass ratio (of the order of 10−2 to 10−1), it is found that the integration over the light particle energy coincides (approximately) with the integration over the relative energy.
Structure and analysis of the B–X band system of GaO
Authors: Yadav B. R. , Rai S. B. , Rai D. K.
Published: April 2011

The electronic spectrum of the GaO molecule has been re-investigated in the region 3600–4200 Å The use of high resolution and dispersion permitted clear resolution of the rotational structure and the formation of head of heads in Δν = + 1 and + 2 sequences is clearly visible. The rotational analyses of the (0,0) and the (1,0) bands have been performed and more reliable molecular constants have been obtained. Intensity anomalies in the bands have been explained on the basis of the true potential energy curves and the associated Franck–Condon factors.
Metastable yield of argon between 23 and 37 eV by electron impact
Authors: Marchand P. , Cardinal J.
Published: April 2011

The metastable yield of argon excited by monoenergetic electron impact has been measured between 23 and 37 eV. Thanks to a large signal-to-noise ratio, many very small structures have been detected superimposed on the metastable continuum and are attributed to Ar− negative-ion states and to highly excited states of Ar. The results are compared with broadband photon yield curves and electroionization curves.
The emission spectrum of the CO2+ ion: rovibronic analysis of the band system
Authors: Gauyacq D. , Larcher C. , Rostas J.
Published: April 2011

The Renner–Teller structure of the [Formula: see text] and Ã2Πu states of the CO2+ ion has been studied thanks to the identification and rotational analysis of the vibronic bands of the [Formula: see text] and [Formula: see text] systems, associated with the first quantum of the bending vibration in the [Formula: see text], Ã, and [Formula: see text] states. The bending structure of the Ã state has been understood and the corresponding parameters ω2 and ε have been determined for the first time. The simultaneous analysis of the 12CO2+ and 13CO2+ appropriate bands has led us to revise our earlier value of the Renner parameter for the [Formula: see text] state, derived from the [Formula: see text] system. In addition, three bands of the main progression ν′00–000 (ν′ = 0, 1, and 2) have been reanalyzed in order to obtain a consistent set of molecular parameters. The main molecular constants (in cm−1; r0 in Å) are summarized below for 12CO2+:[Formula: see text]The accurate experimental data derived from the CO2+ spectrum are discussed in the framework of the most recent theoretical models of the rovibronic structure of linear triatomic molecules.
The electronic spectra of HCl and HF
Authors: Douglas A. E. , Greening F. R.
Published: April 2011

The absorption spectra of HCl and HF have been photographed at high dispersion in the vacuum ultraviolet region. In the HCl spectrum, many new band systems have been identified and 18 vibrational levels of the ionic B1Σ state have been observed. The B1Σ state is found to interact strongly with the Rydberg states. Although many bands have been analysed, much of the HCl spectrum remains unassigned. Analyses of bands associated with the lowest discrete 1Π and 3Π states of HF are presented together with the analyses of two 1Π–X1Σ band systems which lie between the first and second ionization limit. The spectrum of HF is very complex and little of it has been analysed even though the spectral lines are sharp and well resolved. The theoretical problems in understanding the spectra of HCl and HF are discussed.
Callan–Symanzik and Weinberg equations: frame dependence of fixed points
Authors: Acharya R. , Nigam B. P. , Horváth Z.
Published: April 2011

We discuss the relationship between the Weinberg and Callan–Symanzik equations and show that the fixed points of the β functions for the two equations are 'frame-independent' only when γθ(gR, mR/μ) = −1. We also obtain Weinberg's result in the asymptotic limit provided that γθ > −1 and certain explicit mass dependences in scaling factors are dropped.
Charged particle multiplicity in π−–nucleus interactions at 50 GeV/c in nuclear emulsion
Authors: Mozumder A. , Goyal D. P. , Sengupta P. K. , Singh S.
Published: April 2011

Experimental results on charged particle multiplicity of the interactions of 50 GeV/c negative pions with emulsion nuclei are presented. The values of [Formula: see text], [Formula: see text], and D are found to be 8.35 ± 0.17, 7.11 ± 0.25, and 4.75 ± 0.08 respectively. The results of π−–emulsion interactions are compared with those of p–emulsion interactions. The dependence of the parameter RA on mass number A has been examined and compared with the existing models of hadron–nucleus interactions.
High resolution studies of the system of 13C-formaldehyde
Authors: Birss F. W. , Gordon R. M. , Ramsay D. A. , Till S. M.
Published: April 2011

The absorption spectrum of H213CO has been photographed in the region 3600 to 3000 Å under high resolution. Rotational analyses have been carried out for four bands, viz., [Formula: see text], [Formula: see text], [Formula: see text] (Type B), and [Formula: see text] (Type C), and molecular constants are given. Several perturbations have been found and possible mechanisms discussed.
Sur l'existence d'une longueur élémentaire et d'un intervalle de temps élémentaire. II
Authors: Lacroix Robert
Published: April 2011

Giving a value for the elementary time interval t0 is the main purpose of this paper. For this, an analysis of the formula for the energy of a free particle is given, formula which has been found in our first paper on that subject. The value 4.4 × 10−24 s for t0 is in complete agreement with the results of our analysis. An energy band between 75 and 100 MeV is predicted as to be inaccessible for all particles at rest. The solution of the tunnel effect is given in the framework of our theory.
Quantum-mechanical irreversible motion of an infinite chain
Authors: Razavy M.
Published: April 2011

The rate of the energy transfer between the particles in an infinite uniform chain provides an interesting example of a system exhibiting a nonexponential approach to equilibrium. For this system, the quasi-particle description is not convenient, hence, for the purpose of quantization, the total Hamiltonian is decomposed into a sum of single particle Hamiltonians, each containing a time-dependent effective potential energy. The resulting Schrödinger equation for a single particle has a wave-packet-like solution in which the center of the packet moves according to the classical law of motion. The quantal problem shows the same kind of oscillatory decay law as the classical one, and there is no characteristic relaxation time for the system. From the Schrödinger equation, expressions for the total energy, the momentum, and the probability of excitation for each subsystem are obtained. It is shown that the ground state wave function satisfies a Fokker–Planck type equation, and that the equation of motion of each particle remains invariant under the time-reversal transformation. However, the direction of the flow of energy is the same for the actual and the time-reversed motions.
Muonic X-ray intensities in low-Z elements and their hydrides
Authors: Cox C. R. , Dodson G. W. , Eckhause M. , Hart R. D. , Kane J. R. , Rushton A. M. , Siegel R. T. , Welsh R. E. , Carter A. L. , Dixit M. S. , Hincks E. P. , Hargrove C. K. , Mes H.
Published: April 2011

K-series muonic X-ray intensity ratios have been measured in Li. LiH, Be, BeH2, B, B10H14, and LiBH4. The relative intensities of the transitions np → 1s, for n > 2, are enhanced for the higher-Z components in the hydrides compared to the elemental targets. Possible explanations for the observed intensity ratios are discussed.
On an application of Theiss' regularization procedure in quantum electrodynamics
Authors: McKeon Gerry
Published: April 2011

By use in quantum electrodynamics of a parameter-free method of regularization introduced by Thiess, it is found that the massless limit of the two-point function in two dimensions and of the three-point function in four dimensions is not equal to the zero mass value of these graphs.
Determination of the dilation and vibrational contributions to the indirect energy band gap of diamond semiconductor
Authors: Manoogian A. , Leclerc A.
Published: April 2011

An empirical method is used to separate the indirect energy band gap vs. temperature curve of diamond semiconductor into its constituent lattice dilation and vibrational parts. The vibrational mechanism is described in terms of average frequencies over the acoustical and vibrational phonon bands. The results are found to be in agreement with the corresponding averages over the phonon density of states, which are also calculated. The pattern of behaviour exhibited by the group IV A semiconductors from this point of view is discussed.
Multiphoton ionization of Li at the ruby laser wavelength
Authors: Wagner G. , Isenor N. R.
Published: April 2011

Ionization of Li resulting from the interaction of pulsed single-mode (λ = 694.60 ± 0.05 nm, TEM00) ruby laser radiation with an atomic beam was observed. The results can be interpreted in terms of a four-photon process with three-photon resonances with levels in the vicinity of the 19P and 20P Rydberg levels of the unperturbed atom. Both linearly and circularly polarized light were used. The results are compared with the calculated results of others.
Far-infrared dispersive-reflection measurements on NaCl, compared with calculations based on cubic and quartic anharmonicity. II. Low temperature
Authors: Staal P. R. , Eldridge J. E.
Published: April 2011

Accurate far-infrared dispersive-reflection measurements have been performed on a large single crystal of NaCl to yield the reflectance amplitude and phase between 15 and 500 cm−1 at 48 K. These have been augmented with power-transmission measurements in those regions where the phase is small. Some of the difficulties encountered while extending this technique to low temperatures have been discussed, including the unfortunate tendency of the evaporated aluminum reference surface to break away from the crystal. The measurements have been compared with calculations of the damping of the transverse-optic resonance in NaCl, resulting from one-phonon, two-phonon, and three-phonon relaxation processes, which result from isotopic impurities (35,37Cl), cubic anharmonicity, and quartic anharmonicity, respectively. The overall agreement is good but the experimental accuracy is less than that obtained at 290 K. The low temperature results show that a significant discrepancy which was observed at 290 K and which persisted down to 48 K is not the result of neglecting higher-order anharmonicity, as originally supposed, but rather a probable error in the two-phonon spectrum resulting from incorrect values of low derivatives of the crystal potential.
Real space renormalization and the honeycomb lattice
Authors: Jan N. , Moseley L. L.
Published: April 2011

The real space variational renormalization group is applied to the two-dimensional honeycomb lattice. Relevant exponents are obtained for the ferromagnet, antiferromagnet, and layered ferromagnet which are in close agreement with the exact values. We conjecture that the layered ferromagnet will also exhibit a line of continuously varying exponents which is dependent on the strength of the 4-spin coupling between the layers.
Comparison of the major force constant models for cubic systems using a self-consistency condition
Authors: Moore R. A. , Upadhyaya J. C.
Published: April 2011

Previously noted similarities between the central pair potential, CPP, the DeLaunay angular force, DAF, and the Lehman, Wolfram, and De Wames axially symmetric, AS, models for lattice dynamics coupled with criticisms of the DAF model, not applicable to the CPP model, has resulted in a puzzling and confusing picture. New physical arguments are used to develop a self-consistency condition, essentially unrecognized previously, which must be included in the use of all these force constant models. In this event, all of the above three models are proven to be identical. We then go on to examine the Clark–Gazis–Wallis, CGW, model. A systematic procedure is presented allowing a practical extension of the expression for the force constants from the current first and second nearest neighbour interactions to include third nearest neighbour interactions. For fcc systems we show that the previous expressions are incomplete and, consequently, overly restrictive and misleading and, hence, causing a current controversy. Also, we point out that the CGW model reproduces the general tensor force, GTF, model, at least to third nearest neighbour interactions. It is important to note that the application of the above mentioned self-consistency condition restores the Cauchy relation in all the models. Finally, numerical results are presented for the phonon spectra of the bcc metals Na and Nb and the fcc metals Cu and Au in order to demonstrate the practical effect of the self-consistency condition. This effect is seen to be larger for metals having larger Cauchy discrepancies. It is inferred that the force constant models, and hence the self-consistency condition, must be modified to yield the Cauchy discrepancy.
One source of spin–orbit coupling in the Schrödinger representation
Authors: Chatterjee R. , Dixon J. M.
Published: April 2011

The origin of spin–orbit coupling has been investigated in the Schrödinger picture with the constraint of Galilean invariance. A Lagrangian has been constructed with this group symmetry which contains a term that has been interpreted as the damping of the translational motion of the electron in a spinor field. From the Lagrangian a Hamiltonian [Formula: see text] has been formed by classical methods. A unitary transformation has been found which transforms [Formula: see text] into a Hamiltonian [Formula: see text] which contains not only the Zeeman terms, with the correct magnetic moment, but also the spin–orbit coupling.