bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative Piezospectroscopy of the 1s and 2p States of Arsenic Impurity in Germanium
Authors: Martin AD , Fisher P , Simmonds PE
Published: June 2013

The results are presented of a study of the behaviour under uniaxial compression of absorption lines due to transitions from the ground state manifold of states of arsenic impurities in germanium to excited p states. It is found that the shear deformation potential constant Ell of the excited p states and conduction band minima of germanium is 16�4�0�2 eV. The equivalent deformation potential constant of the ground state, here designated as E~, is determined to be essentially the same (one analysis giving E~ = 16�5 � 0�4 e V), a result in contrast to that found for donors in silicon. The results are compared with those obtained by other workers who use a variety of techniques. Good agreement is found between the present results and a number of the others although several discrepancies remain.
Pulsar Magnetospheres: Some Fundamental Considerations
Authors: Westfold KC
Published: June 2013

The equations governing a pulsar magnetosphere under quasi-static conditions are presented in a vector form from which the theory can be developed in a systematic manner. In particular, integrals applicable in the cylindrical and axisymmetric cases are obtained direct from these vector equations.
Corrigendum: Static Quadrupole Moment of the First Excited State of 28Si
Authors: Spear RH , Fewell MP
Published: June 2013

The corrections for mutual excitation given in Table 2 are wrong. They should read +0�2 efm2 for ilQ (instead of -0�2) and + 1 e2 fm4 for ilB(E2; 0+ ->2+) (instead of - 21). Consequently, the results of the experiment are Q2 + = + 15�9 � 3�4 efm2 and B(E2;0+->2+) = 348�20e2 fm4 ? The conclusions of the paper are not significantly affected.
Charge Response of Jellium Surface through Ripplons
Authors: Mahanty J
Published: June 2013

The feasibility of explaining the charge response properties of a jellium surface through excitation of ripplon modes on the electron fluid is examined. It is demonstrated that for a sharp equilibrium density profile the response to the field of an external source through ripplons is different from that through surface plasmons, although in the non-dispersive limit they become identical despite the radical difference in the boundary conditions associated with the two types of excitation. It is suggested that because a free surface is more likely to satisfy the boundary condition for ripplons than for surface plasmons, the surface response properties would be determined more through the excitation of ripplons.
GDR Contribution to Coulomb Excitation. III. 18O
Authors: Barker FC
Published: June 2013

The discrepancy between the values of B(E2) for the transition between the ground and first excited states in 180 as obtained from Coulomb excitation measurements and from other measurements is here attributed to the giant dipole resonance (GDR) contribution to Coulomb excitation; an estimate based on shell model calculations predicts this contribution to be much larger than previously assumed.
Intermediate-energy Electron Scattering by Atomic Hydrogen
Authors: McCarthy IE , Stelbovics AT
Published: June 2013

Both elastic and inelastic scattering are studied in the framework of the close-coupling equations. The models are formulated in terms of integral equations for T matrices in momentum space. This representation enables one to study the effects of approximations to the multiple-scattering series in a direct manner. For elastic scattering we can thus establish that the approximations made in using a second-order optical-potential formalism give rise to at most a 10% error in the reaction mechanism at 50 eV and considerably less at higher energies. Inelastic Is-2s and Is-2p scattering is analysed in terms of a three-state close-coupling model and approximations to it.
Electrostatic and Relaxation Effects in Ionization of Intermolecular Complexes
Authors: Barrie Peel J
Published: June 2013

The shifts in experimental ionization energy (IE) resulting from complexation between the (CH3hO and HF molecules are analysed theoretically with small basis set molecular orbital calculations. Initial state effects are separated according to the Morokuma decomposition procedure which distinguishes electrostatic, polarization and charge transfer contributions. The electrostatic effect, arising from the HF molecule, changes the potential energy of the no electrons on (CH3hO.
Gallium Arsenide as a Competitor to Silicon for High-speed Amplification and Switching
Authors: Ladbrooke PH , Debuf DR , Nanayakkara K , Wilkins DR
Published: June 2013

A review is given of the physical and technological factors which affect the electrical behaviour of field-effect devices for high-speed applications. Ballistic electron transport is shown to lead to an electron transit time under the gate electrode which is shorter in GaAs than in Si field-effect transistors (FETs), providing a possible basis for exploitation of transport effects in high-speed devices. Some electrical characteristics of practical Si and GaAs field-effect structures are presented.
The Contribution of Surface Analysis and Surface Science to Technology
Authors: Powell CJ
Published: June 2013

Surface science is a rapidly growing field offering many scientific and technological challenges. New experimental and theoretical tools have been developed which can be used to probe, at a fundamental atomic and molecular level, the physics and chemistry of complex processes at solid surfaces. Surface characterization, particularly surface analysis, is now an integral part of many technologies and industries (e.g., catalysis, coatings, corrosion, semiconductor devices, computer, automobile and communications) for many different applications (e.g., failure analysis, quality control, process and device development). processes
Drift and Diffusion of Electrons in an Atomic Gas between Closely Spaced Electrodes. II. Effect of Inelastic Collisions
Authors: McMahon DRA
Published: June 2013

Previously derived source functions and generalized electron absorption coefficients are employed in a new method to obtain the electron flux in an atomic gas between closely spaced electrodes taking into account inelastic collisions. Energy losses due to elastic collisions are assumed to be relatively unimportant compared with inelastic collisions. The initial energy of the electrons at the source and the applied electric field are assumed to be insufficiently large to produce more than one inelastic collision for any electron, but otherwise there is no restriction on the number of inelastic thresholds. Given these restrictions it is shown that the results obtained are consistent with the usual two-term approximation to the Boltzmann equation. It is further demonstrated that the electrodes have little effect on the electron flux when the generalized electron absorption coefficients are dominated by electron-atom collisions. Conditions under which inelastic collisions have a significant effect on the electron flux are derived. Finally, the connection between the present steady state analysis and quantities obtainable by a pulsed electron source experiment are discussed.
L-shell Ionization of Sn and Gd by 20?100 keV Electron Impact
Authors: Baxter GW , Spicer BM
Published: June 2013

Measurements have been made of the relative X-ray .production cross-section ratios L./Ly, L./Lp and L./Ll using electrons of energy from 20 to 100 keV incident on thin targets of tin and gadolinium. The experimental ratios obtained are compared with theoretical values. Modification of these ratios due to the formation of double-vacancy atomic states has been calculated, but this effect on its own is not sufficient to account for the discrepancy between the L./Ll theoretical and experimental results for tin.
Dynamics of a Nonlinear Diatomic Chain
Authors: Henry BI , Oitmaa J
Published: June 2013

We examine nonlinear lattice excitations in a model for a solid which may undergo a displacive structural phase transition. In particular, we investigate the field equations for a diatomic chain of atoms including nonlinear potentials on one species. We identify three classes of excitations in this model. These are linearized phonons, large amplitude solitary waves, and nonlinear phonons. Interactions between the linear phonons and the nonlinear modes give rise to a translation mode which is a further solution of the field equations. The linear and nonlinear phonons are also direct solutions of the discrete equations of motion. However, using the molecular dynamics technique we find that kink-type configurations occur for a much larger parameter space in the discrete lattice than they do in the continuum description. All the stable excitations of the field equations should be included in a formal description (e.g. statistical mechanics) of the model.
Cosmic Ray Showers at 1016 eV
Authors: Clay RW , Gerhardy PR
Published: June 2013

A summary is made of some cosmic ray shower results obtained at the University of Adelaide Buckland Park air shower array. It is demonstrated that a number of air shower parameters undergo appreciable changes at common shower sizes.
New H2O Masers associated with Main-line OH Masers in the Galactic Longitude Range 3° to 60°
Authors: Caswell JL , Batchelor RA , Forster JR , Wellington KJ
Published: June 2013

A search in the direction of OH masers emitting at 1665 or 1667 MHz has yielded 11 new H20 masers. The new sources are discussed individually. The overall statistics of the search show that out of a total of 55 OH masers in the 3� to 60� galactic longitude range at least 36 have H20 maser counterparts.
Absolute Cross Sections of Proton Induced Reactions on 65Cu, 64Ni and 63Cu
Authors: Sevior ME , Mitchell LW , Anderson MR , Tingwell CIW , Sargood DG
Published: June 2013

Absolute cross sections have been measured for (p, y) reactions on 63CU, 64Ni and 63CU over proton energy ranges of 1,05-3 '25, 1�00-3 �45 and 1�05-4� 70 MeV respectively, for (p, n) reactions over proton energy ranges from threshold to 3� 25,3' 80 and 4�86 MeV respectively, and for 63CU(p, p')63CU over a proton energy range of 1�05-4'00 MeV. All the data are compared with global statistical model calculations. The agreement, to within a factor of 2, between theory and experiment is regarded as satisfactory for a global code, but the 64Ni data are suggestive of a closed shell effect at Z = 28.
Solenoidal Excitation of Eigenmodes in Cylindrical Magnetized Plasma with Two Ion Species
Authors: Kieu TD , Sy WN-C
Published: June 2013

The conditions for the experimental observation of new types of eigenmodes in a typical laboratory magnetized plasma with two ion species are discussed. It is shown that the most favourable condition occurs during the current carrying phase of the discharge, with an appropriately chosen mixture of ions.
Transport Properties of Nearly Magnetic Alloys and Metals
Authors: Kaiser AB
Published: June 2013

We give an elementary review of how simple spin fluctuation models can account for the distinctive transport properties of nearly magnetic alloys and metals. The principal systems considered are dilute alloys such as PdNi in which host and impurity have somewhat similar electronic structure but with the impurity more nearly magnetic than the host. Similar effects occurring in pure metals or concentrated alloys are also mentioned.
Effect of Excited States on Thermonuclear Reaction Rates
Authors: Sargood DG
Published: June 2013

Values of the ratio of the thermonuclear reaction rate of a reaction, with target nuclei in a thermal distribution of energy states, to the reaction rate with all target nuclei in their ground states are tabulated for neutron, proton and (X-particle induced reactions on the naturally occurring nuclei from 2�Ne to 70Zn, at temperatures of 1, 2, 3�5 and 5 x 109 K. The ratios are determined from reaction rates based on statistical model cross sections.
The Strangeness-exchange Reaction K¯d ? App¯ in FIight
Authors: Dalitz RH , Deloff A
Published: June 2013

The data on the forward reaction K -d --> Apn- at 700 MeV/c are compared with calculations using semi-phenomenological one-boson-exchange hyperon-nucleon potentials and KN --> nY amplitudes deduced from two-body data. This gives a new test of these potentials, since only the spin-triplet potentials are involved, in contrast with all other scattering data, which depend on a spin-weighted average of singlet and triplet contributions. However, this comparison does not yet provide an empirical distinction between Potential! of Brown et al. (1970) and Potential F of Nagels et al. (1979). The KN --> nI: and KN --> nA amplitudes interfere in this reaction, so that its analysis can yield new knowledge of them; the present work requires a phase for the KN --> nA amplitude different by about - 135� from that deduced from partial-wave analyses.
Comparison of DWBA and Adiabatic Treatments of Deuteron Breakup Angular Correlations
Authors: Amakawa H , Austern N
Published: June 2013

Angular correlations calculated by the adiabatic method are shown to agree better with experiment than ones calculated by the prior-form DWBA. The problems of prior-form DWBA and its relationship to other methods of calculation are discussed.
Electron Cyclotron Maser Emission near the Cutoff Frequencies
Authors: Hewitt RG , Melrose DB
Published: June 2013

An earlier discussion of loss-cone driven cyclotron masers is extended to cover the case where the emission occurs close to the cutoff frequency of the 0 mode or the x mode. In general, wave growth may occur in one or two bands, and when two bands are allowed the lower band is close to the cutoff frequency. With the exception of the x mode at 8 = 1, growth in the lower band is allowed only for OJp/D. > 8 and cos28 > t for the 0 mode and for OJp/Q. > {s(s-I)}-!- and cos28 > (s-I)/8 for the x mode, and growth in the lower band has no particularly favourable features when allowed. For the X mode at 8 = 1 both bands are allowed for all OJp/D. $ 1 and growth in the lower band is possible over a wide range of angles in a very narrow frequency band. The spatial growth rate can be quite large due to the small group speed. However, the large spatial growth rate is offset by the short pathlengths for growth in a slowly spatially varying magnetic field due to the very narrow bandwidth of the growing waves. It is found that growth in the lower band is at best no more effective than growth in the upper band. We discuss the relative merits of growth in the two bands in a suggested application to terrestrial kilometric radiation. We also discuss cyclotron theories for type I solar radio emission, pointing out that our results do not favour such theories, and for solar microwave spike bursts.
Free Fall onto Magnetized Neutron Stars
Authors: Salpeter EE
Published: June 2013

Some compact X-ray sources show evidence of cyclotron line radiation from excited electron Landau orbits, powered by hydrogen and helium falling onto a neutron star atmosphere along the magnetic field. The slowing of the incident matter is discussed, including the spread in energy loss due to Coulomb scattering and direct nuclear reactions for disintegrating the QC particles-two problems which were first solved by Stuart Butler. The (X disintegrations, followed by neutron capture, lead to nuclear )I rays; the )I-ray intensity is (indirectly) coupled to the Coulomb energy loss and the cyclotron line emission.
Coulomb Excitation of the 2·615 MeV (3?) and 4.086 MeV (2+) States of 208Pb
Authors: Vermeer WJ , Esat MT , Kuehner JA , Spear RH , Baxter AM , Hinds S
Published: June 2013

Coulomb excitation studies of the 2�615 MeV (3-) and 4�086 MeV (2+) states of 208Pb have been carried out using 12C and 160 projectiles at various energies and scattering angles. Results for the 3- state are: B(E3;O+~3-) = O'611�O'012e2b 3 ; and the static quadrupole moment Q3 - = - O�34� O�15 e b, which is larger in magnitude than most theoretical calculations. Results for the 2+ state imply that Q2+ = -0�7�0�3 eb if a value for B(E2;0+~2+) determined from electron scattering work is assumed.
Modelling Reactive Gas Flows within Shock Tunnels
Authors: Vardavas IM
Published: June 2013

An iterative method is presented for modelling reactive gas flows within shock tunnels. The method overcomes both the problem of the stiffness of the chemical rate equations, which arises due to the greatly varying reaction' rates, and the throat singularity in the velocity equation for subsonicsupersonic flow within a Laval nozzle. The effects of Coulomb interactions which depress the ionization potential of the ionic species can also be included because of the iterative nature of the method. The method computes the state of the gas both along the flow and within the reservoir or stagnation region. Sample computations are given for air, carbon dioxide and nitrogen for reservoir-nozzle gas flows and for flows behind normal shocks.
The Influence of Vertical Vorticity on Thermal Convection
Authors: Murphy JO , Lopez JM
Published: June 2013

The single-mode equations of Boussinesq thermal convection have been modified to include the vertical component of vorticity, which has led, in certain parameter ranges, to a new family of solutions for stationary convection in the absence of external constraints. The features of these solutions are discussed and a comparison with the family of solutions possessing zero vertical vorticity, which are also solutions of the equations, is presented. Specifically, these new solutions are characterized by a lower vertical velocity and heat flux, nonzero vertical vorticity thereby giving them a helical structure and considerably reduced thermal boundary layers in comparison with the family of solutions with zero vertical vorticity. It is to be stressed that this new family of solutions is not due to externally applied influences such as rotation or a magnetic field, the only driving force present being that due to buoyancy.
Some Aspects of the U(1) Problem and the Pseudoscalar Mass Spectrum
Authors: Christos GA
Published: June 2013

A complete discussion of the nonet pseudoscalar mass spectrum and related topics is given. The U(l) problern is briefly reviewed and the large-N point of view is considered. The necessity for a vector ghost gluonic particle, in order to resolve the U(l) problem, is stressed. Scalar ghosts and the Kogut-Susskind mechanism are shown to be insufficient. An analysis of the 1]-1]' mixing problem, with and without PCAC corrections, is made and it is suggested that the singlet decay constant may be nearly twice as large as the other octet decay constants. A general discussion of PCAC corrections is given and the remaining pseudoscalars are considered. As byproducts quark mass values are given and the rnq dependence of <ijq) is elucidated. In the usual scheme, it is found that (8S) ~ 1�48(uu). The 1] ~ tttttt decays are also discussed.
Horizontal Wave Number Dependence of Type II Solutions in Rayleigh?Benard Convection with Hexagonal Planform
Authors: Lopez JM , Murphy JO
Published: June 2013

The horizontal wave number dependence of the hexagonal planform solutions for the RayleighBenard convection problem, which have a nonzero vertical component of vorticity (type II solutions), has been established. Over the range of wave numbers which support cellular convection, comparisons between the thermal transport characteristics of these cyclonic type solutions and those traditionally obtained from nonlinear investigations of the single horizontal mode equations (type I solutions) have been made. From the numerical results obtained, it is found that the cell aspect ratio which maximizes the heat flux of type II solutions is larger than that for type I solutions, at quivalent parameter values, and that the value of the horizontal wave number giving maximum Nusselt number for type II solutions increases with Rayleigh number and decreases with Prandtl number.
Allowed and Forbidden n = 2?2 Transitions of the Elements Kr and Mo
Authors: Glass R
Published: June 2013

Relativistic intermediate-coupling wavefunctions are used to evaluate transition energies, line strengths and transition probabilities for all allowed and forbidden n = 2-2 transitions for krypton and molybdenum beryllium-like ions. Our results are in very good agreement with those calculated using the relativistic multi-configuration Hartree-Fock approximation. These calculations were carried out under the same physical assumption that the dominant correlation effect is the n = 2 intra-shell correlation. We also discuss the importance of relativistic effects on the radial functions, the relativistic intermediate-coupling scheme in the variational process, the importance of radiative corrections for transition energies between states with different occupation of the 2s shell, and the relative importance of intra- versus inter-shell correlation effects.
Dispersion in a Relativistic Quantum Electron Gas. II. Thermal Distributions
Authors: Melrose DB , M Hayes Leith
Published: June 2013

The dispersion functions which appear when the response of a non-degenerate thermal electron gas is treated using a relativistic quantum theory are shown to be the same as the functions which appear in the non-quantum limit. These functions are evaluated at two speeds V1 and V2 which in the non-quantum limit reduce to the phase speed ca/I k I. It is shown that the effects of partial degeneracy may be included by expanding about the non-degenerate limit, and the expansion of the response functions is given explicitly. It is also pointed out that thermal corrections to the completely degenerate limit may be included using a standard technique and the lowest order corrections are given.
Universal Features of Tangent Bifurcation
Authors: Delbourgo R , Kenny BG
Published: June 2013

We exhibit certain universal characteristics of limit cycles pertaining to one-dimensional maps in the 'chaotic' region beyond the point of accumulation connected with period doubling. Universal, Feigenbaum-type numbers emerge for different sequences, such as triplication. More significantly we have established the existence of different classes of universal functions which satisfy the same renormalization group equations, with the same parameters, as the appropriate accumulation point is reached.
Solar Photodetachment Rates of Monatomic Anions
Authors: Helmy EM , Woo SB
Published: June 2013

The solar detachment rates of all stable atomic anions belonging to elements in the main body of the periodic table have been calculated. Multi-channel photodetachment effects owing to fine structure levels and temperature effects are included in the treatment. All told the solar detachment rates of 31 anions at 300 and 104 K are made available. The rates show strong correlation to the group number in the periodic table. The higher the group number of the element, the lower is its detachment rate. Caesium has the highest detachment rate of 82 s-1, while fluorine has the lowest rate of 0�069 S -1. The calculations shown here may be useful to researchers conducting experiments on ionospheric modification where negative ions which are not normally found in the atmosphere may appear in abundance.
The Two-state Problem in Diffraction, NMR and Laser Atomic Spectroscopy
Authors: Moodie AF , Wilkins SW , Bastow TJ , Hannaford P
Published: June 2013

It is pointed out that the basic mathematical structure underlying the physical techniques of (i) two-beam X-ray (or high-energy electron) diffraction from crystals, (ii) nuclear magnetic resonance (NMR) for a spin-i1/2 system and (iii) laser-induced optical transients from atoms is essentially the same. The simplicity of the formalism is such as to readily enable one to tabulate correspondences between the various physical parameters involved in the different techniques and to identify corresponding experimental configurations in many cases.
Detection of Radiation Damage in Organic Crystals
Authors: Seiler Paul , D Dunitz Jack
Published: June 2013

In X-ray diffraction experiments with single crystals, the loss in intensity of Bragg reflections caused by radiation damage can become more severe at higher scattering angle, similar to the effect of increased thermal motion or disorder. Long exposure to X rays can also lead to an increase in the lattice dimensions, similar to the effect of thermal expansion. Both effects are illustrated by observations with 4,5, 10, ll-tetraoxa-I, 2, 7, 8-tetraazatricyc10[6.4.1. 12,7]tetradecane made in connection with a charge density study of this molecule. Recommendations are made for the choice of standard reflections and measurement strategies for accurate crystal structure analysis of radiation sensitive compounds.
Electron Microscope Images of Icosahedral and Cuboctahedral (f.c.c. Packing) Clusters of Atoms
Authors: Barry JC , Bursill LA , Sanders JV
Published: June 2013

Images have been computed of closed-shell clusters of 55, 147 or 309 atoms in regular icosahedral and cuboctahedral (f.c.c.) packing for an electron microscope operating at 100 keV, with Cs = 0�7 mm and resolutions of 0�3 and 0�2 nm. The object is to test the possibility of distinguishing the two structures from their images. The results show that sizes and shapes are well represented at optimum defocus but that similar images are often given by both structures. Discrimination could be made for some images at excessive underfocus at 0�2 nm resolution.
Burgers Vectors in Secondary Grain Boundary Dislocation Structures for near S9, S27 and S81 Boundaries
Authors: Forwood CT , Clarebrough LM
Published: June 2013

The Burgers vectors of secondary grain boundary dislocations, forming networks in near ~9, ~27a, ~27b and ~81a grain boundaries in polycrystalline specimens of a Cu +6 at. % Si alloy, have been determined using the technique of image matching, which involves a comparison of experimental and theoretical electron micrographs. In all cases, the Burgers vectors of the secondary grain boundary dislocations were found to be vectors of the DSC lattice corresponding to the appropriate CSL orientation. Further, in most cases, the Burgers vectors were found to be basis DSC vectors.
States of 5He and 5Li
Authors: Barker FC , Woods CL
Published: June 2013

A recent shell model calculation has predicted a low-lying! + level in 5He, in apparent conflict with experimental results. We have confirmed the prediction with an alternative shell model interaction chosen specifically to fit properties of light nuclei. The level is expected to be very broad so that it would not be easily seen in reactions. It should contribute significantly to n-a phase shifts, but did not appear in previous analyses because of the small value of about 3 fm chosen for the channel radius a. A ! + level at the expected energy of about 7 MeV is obtained for a ::::: 5�1 fm. Broad ~ + and ~ + levels are then found at about 14 MeV in agreement with the shell model calculations. Properties of the low-lying ~ - and! - levels in 5He and 5Li are discussed, but the measured values now available do not favour a particular value of the channel radius.
The Mobility of Li + Ions in Helium and Argon
Authors: Cassidy RA , Elford MT
Published: June 2013

A drift tube-mass spectrometer system employing Bradbury-Nielsen shutters has been used to measure the mobility of Li + ions in He at 294 and 80 K and Li + ions in Ar at 294 K. The E/N range used was 3 to 80 Td (1 Td == 10 - 21 Y cm2). The zero field reduced mobility for Li + in He was found to be 22�81�0�11 cm2 y-1 s-I at 294 K and 19�64�0�29 cm2 y-1 s-I at 80 K. The value for Li+ in Ar at 294 K is 4�66�0�22 cm2 y-1 s-I. The reduced zero field mobility for the cluster ion Li +. He in He at 80 K and low values of E/ N was found to be 14�84 � 0�22 cm2 y -I s - I. The equilibrium constant for the formation and dissociation of Li + . Ar cluster ions at 294 K was obtained by fitting to the variation of the measured mobility with gas number density at low E/N values. The value obtained, corresponding to thermal equilibrium at 294 K, was (4�0.5)xlO- 19 cm3 .
Electron Capture Decay Energies of 153Gd and 175Hf
Authors: von Dincklage Ralph-D
Published: June 2013

The electron capture Q values of 153Gd and 175Hf are analysed by using properties of their /3 decays to different levels belonging to the same rotational family in the daughter atoms. The results are Q = 500 go keV for 153Gd and Q = 700 go keV for 175Hf. They agree with data from nuclear reactions but reject smaller values based on K capture probabilities.
New Materials Applications in Solar Spectral Analysis
Authors: M Rust David
Published: June 2013

The use of lithium niobate and liquid crystals in solar instrumentation designed for automatic measurement of spectral line shifts is described. A solid Fabry-Perot etalon of lithium niobate has an acceptance angle 5�3 times greater than an air-spaced Fabry-Perot filter for the same allowed passband broadening, and the lithium niobate device has no moving parts. The use of liquid crystals in Zeeman-effect analysers is also described. For a given phase retardation, liquid crystals require -1/1000 the voltage of solid crystals. They hold promise as reliable, long-lived variable retarders because they are free of the high-voltage breakdown problems of crystals such as potassium dideuterium phosphate (KDP). Progress toward implementation of devices with lithium niobate and liquid crystals in a solar telescope is described.
Future Techniques and Instrumentation in Solar?Stellar Physics
Authors: M Beckers Jacques
Published: June 2013

I review the likely instrumental developments for the study of solar--stellar physics. The study of processes known to exist on the Sun and occurring on stellar surfaces will require increasingly more sophisticated instrumentation and larger telescopes. I specifically describe instrumentation required for the study of stellar activity and activity cycles, stellar rotation, stellar surface motions and magnetic fields, stellar pulsations, stellar chromospheres and coronas and stellar winds.
Vistas on Stellar?Solar Atmospheres
Authors: Peeker J-C
Published: June 2013

The evolution of the modelling of the stellar atmosphere towards greater physical consistency is described briefly. The progressive relaxation of stringent hypotheses (such as RE, L TE, HE, plane-parallel geometry) in all layers characterizes this evolution. We discuss roughness (i.e. departures from sphericaI geometry), the origin of the concept, and how its recent application to Skylab and OSO-8 UV data shows its importance, difficult to take into account accurately, but not to be overlooked. In the last part of the paper we argue for a general overall coupling between mechanisms which characterize the stellar-solar machinery described.
The Mobility of K+ Ions in Helium and Argon
Authors: Cassidy RA , Elford MT
Published: June 2013

'A drift tube-mass spectrometer has been used to measure the mobility of K + ions in helium at 294 and 80 K over the EIN range 5-60 Td and in argon at 295 K over the EIN range 3-120 Td. The zero field reduced mobility KO for K + in He was determined to be 21� 14 � 0 . 11 cm 2 Y - 1 s - 1 at 294 K and 17 �32�0�26 cm2y-1 s-l at 80 K. The value of KO obtained for K+ in Ar at 295 K is 2 �640�0�013 cm2 y-1 s -1. The results are compared with those obtained in previous measurements.
Fast Timing of Air Shower Fronts
Authors: Clay RW , Ciampa D
Published: June 2013

In order to design a telescope for use in ultra-high energy y-ray astronomy one needs to carefully consider those effects which determine the system angular resolution. This paper considers detector and discriminator designs for such a system including a consideration of the effect of the spread of particles in the shower front. An angular resolution of ~ 10 at energies of 10 15 e V can be achieved
Corrigendum: Numerical Simulations of Large-scale Solar Magnetic Fields
Authors: DeVore CR , Sheeley Jr NR , Boris JP , Young Jr TR , Harvey KL
Published: June 2013

On p.1000, both the fourth and fifth terms on the left-hand side of equation (1) should be preceded by minus signs. Line 22 on the same page should read: ' ... obtained by integrating equation (1) for S = 0, ...
Dependence of the Universal Constants on the Nature of the Maximum of the Mapping Function
Authors: Delbourgo R , Hart W , Kenny BG
Published: June 2013

Empirical and analytical evidence is presented for the relation 8 N = {( z - 1) / (z - D) a N between the universal constants describing the approach to the accumulation points, for cycles undergoing multiplication by period N, in one-dimensional maps possessing an order z maximum
Ionization Growth Between Hyperboloidal Needle and Plane Electrode under r.f. Electric Fields in N2. I. Image Intensifier Observations and the Influence of Space Charge Accumulations
Authors: Sato N , Haydon SC
Published: June 2013

The corona onset and subsequent plasma growth in the space between a hyperboloidal needle and plane electrode is investigated by highly time-resolved image intensifier techniques. The use of the special geometry has enabled appropriate mathematical analysis of space charge effects to be carried out and has provided clarification of the underlying causes of some significant features of ionization growth under r.f. conditions. The effect of u.v. filtering on the corona images is also examined.
A Phenomenological Nucleon-Nucleon Interaction
Authors: Berge L , Petris L
Published: June 2013

A phenomenological NN interaction has been developed in momentum space to fit the elastic scattering phase shifts, the deuteron properties and to saturate nuclear matter. The special features of this interaction are gaussian momentum dependent form factors and the use of only three mesons to characterise the phase shifts.
Current Developments in the Relativistic Quantum Mechanics of Atoms and Molecules
Authors: Grant IP
Published: June 2013

Current work in relativistic quantum mechanics by the author and his associates focusses on four topics: atomic structure theory using the GRASP package (Dyall 1986); extension of GRASP to handle electron continuum processes; the relation of quantum electrodynamics and relativistic quantum mechanics of atoms and molecules; and development of methods using finite basis set expansions for studying electronic structure of atoms and molecules. This paper covers only the last three topics, giving emphasis to growing points and outstanding difficulties.
Inclusion of Relativistic Effects in Electronic Structure Calculations
Authors: Dyall KG
Published: June 2013

The effects of relativity on atomic and molecular structure are discussed with an indication of their importance as a function of atomic number. Perturbation methods for the inclusion of relativistic effects are briefly analysed in terms of the Dirac equation; the multi-configuration Dirac-Fock method for the variational treatment of relativistic effects is then discussed in more detail. Finally, a case study on 2p ionisation in Ca is presented, in which higher-order relativistic effects are important.
Four-wave Processes Involving Two Low Frequency Waves
Authors: Melrose DB
Published: June 2013

The probability is calculated for a four-wave process in which a Langmuir wave combines with two low frequency (ion sound) waves to produce another Langmuir wave or a transverse wave. The major part of the calculation involves relevant approximations to the quadratic and cubic nonlinear response tensors. An estimate based on observational data from the interplanetary medium suggests that the four-wave process may be significant in solar radiophysics.
Heat Transport in Liquid Filled Tubes
Authors: Schmid R , Pailthorpe BA , Collins RE
Published: June 2013

When heat is applied to a liquid filled tube, the liquid moves under buoyancy forces which arise from density variations. In long thin tubes, inclined at. an angle to the horizontal, two counter-flowing streams of liquid are observed which extend over virtually the whole length. A simple one-dimensional model is developed in which an analysis of heat flows into and between the two streams is made. This is used to predict the temperature in the system and the average fluid velocities at any point in the tube. The results of the model are in good agreement with experimental measurements on these tubular systems, and on a planar convection cell. Systems such as this can exhibit very large effective thermal conductances, and may be useful as a heat extraction device in evacuated tubular solar collectors.
Low Temperature Heat Capacity and Thermal Expansion of KCI Containing a Low Concentration of Li+
Authors: Collins JG , Collocott SJ , Tainsh RJ , Andrikidis C , White GK
Published: June 2013

The linear thermal expansion coefficient a from 180 mK to 36 K and the heat capacity per gram cp from 0�5 to 10 Kare reported for KCl containing approximately 100 ppm Li+. Contributions to a and cp attributable to the impurity have been identified and analysed on the basis of a model in which the Li + ions reside about 0�05 nm from the equilibrium cationic site in any of the (111) directions. There is consistent quantitative agreement with a Schottky-like term that arises from the eightfold degeneracy of the level splitting; the splitting parameter is 1� 5 K. The large (- 160) Grtineisen parameter associated with the impurity contribution is evidence for a quantum-mechanical tunnelling process, and agrees with values derived from independent measurements of the spectroscopic and dielectric responses of this system under pressure.
Excitation of Swift Heavy Ions in Foil Targets. III. Initial Populations of Rydberg States
Authors: Hay HJ , Treacy PB
Published: June 2013

Results are reviewed of experiments in which Rydberg states with high principal quantum numbers (n :<:: 20) are excited by foil targets in transmitted heavy ions. A uniform procedure is described for analysis of the decays downstream of such states using a Monte Carlo method. Previously observed X-ray decays of 130 MeV Br Rydberg ions into L vacancies are analysed and numerical populations of initially generated states are deduced. It is found that the initial states may be described as mainly statistical, i.e. all substates having equal weights, with 63% of initial ions in such states. Some X-ray lines are found to come from high-n (:<:: 50), low-/ (;S; 2) states. There is evidence for an unknown post-foil mechanism feeding the 3s electron state.
Investigation of the Structural and Magnetic Properties of the Light Rare Earth Elements and Their Intermetallic Compounds
Authors: Creagh DC
Published: June 2013

The experimental requirements for the investigation of the structural and magnetic properties of the light rare earth elements and their intermetallic compounds at synchrotron radiation sources are discussed. Experimental techniques considered include X-ray topography, energy dispersive X-ray diffraction and X-ray powder diffraction.
Crystal Structure Analysis and Refinement Using Integrated Intensities from Accurate Profile Fits
Authors: Will G
Published: June 2013

Careful experimental techniques, especially using synchrotron radiation facilities, give well resolved diffraction patterns. Remaining overlapping peaks can be separated by profile fitting and profile analysis. The derived parameters are: peak position for lattice constants, integrated intensities for crystal structure work and halfwidth for line broadening analysis. Crystal structure refinements with the powder least squares program POWLS yield R factors routinely around R = 1�5% and as low as R = 0�6%. For actual structure analysis Fourier maps have been calculated in the case of the orthorhombic olivine analogue Mg2Ge04. Another non-trivial example concerns Ce02, where chemical bonding features are derived. From an analysis of anomalous dispersion in Yb20 3 the correction terms f' have been derived as a function of energy for four wavelengths measured close to the L-absorption edge of Yb.
Pressing the Limits of Rietveld Refinement
Authors: Young RA
Published: June 2013

Two examples are given, one with X-ray data and one with netltron data, of the determination of structural detail which appear to be at the edge of current possibility for the Rietveld structure-refinement method. In the first example, 2�2 wt% Sb substituted in CalO(P04)6F2 was located. X-ray powder diffraction data collected with special attention to intensity precision and scale constancy were used. The problem was solved through comparison of intra-sample site-occupancy ratios between Sb-doped and undoped samples. In the second example, high quality, high resolution neutron powder diffraction data were required. The problem was to distinguish between two subtly different models of kaolinite for which the R-weighted-pattern values differed only by 2 or 3 units in the third digit and, particularly, to understand the basis for the consistent programmatic choice of one of the models (PI) over the other. The answer was found in the calculated and 'observed' intensities for (h+ k)-odd reflections; although they were very small, less than 1% of the intensities of the main reflections, many of them were distinctly nonzero. Even though these reflections were not separately observable, because of overlap and small size, they nonetheless correlated with one model sufficiently better than the other to produce the consistent choice.
Spectroscopic Studies of the Energy Levels of the Nd3+ Ion in Single Crystals of SrO.6Al2O3
Authors: Tajalli H
Published: June 2013

A detailed study of the polarised absorption and fluorescence spectra and the selective excitation spectra of the Nd3+ ion in the SrO.6Al20 3 host lattice was carried out over the temperature range 4�2 to 500 K. The empirical energy level schemes were determined for two dominant sites of Nd3+ in SrO.6Al20 3 up to 20000 cm -1. The intensity, linewidth and thermal shifts of the transition lines with 4f3 configuration were investigated. The vibrational transitions of Nd3 + : srO.6Al20 3 were also investigated using Raman spectroscopy. The results of the study provide information on the suitability of Nd3+ : srO.6Al20 3 as a solid state laser material.
On the Radiation from a Rotating Dipole
Authors: Briggs Keith
Published: June 2013

We reconsider a thought experiment recently described by Comay (1987) consisting of a rotating dipole emitting electromagnetic radiation. We show that there is no confti6t with energy conservation, at least to tenth order in angular velocity.
A General Physical Model for RMF Current Drive
Authors: Hugrass WN
Published: June 2013

Rotating magnetic fields (RMF) have been used successfuly to drive steady currents in plasmas in many experiments. Some recent experimental and theoretical results did not seem to agree with the standard model based on assuming that the electrons are 'tied' to the lines of the RMF. A more general model based on the concept of flux preserving motion is developed in this paper. It appears that this model provides a unified approach for predicting the qualitative features of RMF current drive under a variety of conditions.
Covariant Response Tensors for Spin Zero and Spin One Boson/Anti-Boson Plasmas
Authors: WilIiams DRM , Melrose DB
Published: June 2013

A fully covariant and general expression for the relation between the 4�current and the 4-potential for spin 0 and spin 1 particle/anti-particle plasmas is presented. The response tensors obtained are compared with the spin t case, and are shown to reproduce the classical expressions in the appropriate limit. The longitudinal and transverse parts of the linear response tensor are evaluated for an isotropic particle/anti-particle distribution, and explicit expressions are obtained for the completely degenerate limit.
Baryon Structure and QCD
Authors: Cahill RT , Roberts CD , Praschifka J
Published: June 2013

From QCD we derive a three-body Faddeev-type formulation of baryons, as qqq colour-singlet states bound by gluon exchange, which is covariant, has dynamically hidden chiral symmetry and incorporates the colour dynamics. The formulation exploits the dynamical role of colour "3 diquark substructure in baryons to simplify computations. For non-zero current quark masses the jP = ~ + and ~ - baryon octet mass formulae are shown to satisfy the Gell-Mann-Okubo and the Coleman-Glashow multiplet mass relationships.
Diquarks and the Bosonisation of QCD
Authors: Cahill RT , Praschifka J , Burden CJ
Published: June 2013

Previously the functional integral formulation of quantum chromodynamics <QCD) has been transformed into one involving colour singlet and colour octet bilocal fields describing qq states. While useful in determining the effective action for the observable colour singlet mesons, this formulation is of no use in determining the effective action for the baryon states. Here we show that there exists an alternative bosonisation of QCD in which the colour singlet meson fields and the colour triplet diquark fields form a complete set of functional integration variables. These diquark fields play an essential role in the colour singlet baryon states.
Time-dependent Studies of Optical Bistability in Atomic Sodium
Authors: Schulz WE , MacGillivray WR , Standage MC
Published: June 2013

A bistable system consisting of an optical cavity with a medium of sodium atomic beams has been subjected to square pulses of light resonant with a D transition. The lifetimes of the field in the cavity and of the atomic medium are approximately equal. The system transmission data recorded has been compared with simulated data calculated from a theoretical model which treats the atomic energy configuration associated with the D lines as a three-level, lambda-type. Good qualitative agreement is obtained showing the system switching on to the high transmission branch. In particular, as the intensity of the input pulse ends, from the high intensity side, to the low to high branch transition threshold, switching is delayed by a time which is more than one order of magnitude longer than the field and atomic lifetimes.
Ionospheric Es in the Southern Hemisphere Temperate Zone. I. Seasonal Characteristics of f0 Es
Authors: Baggaley WJ
Published: June 2013

Detailed seasonal variations of fo Es occurrence are presented for the Southern Hemisphere Temperate zone from the analysis of approximately twenty years of ionosonde data for ten stations (9"�4 to 52"�6 geographic latitude) in the Australasian region. Significant short term features are found: a late autumn enhancement strongest at about 20"S and evidence of a secondary summertime peak one month before the solstice. A comparison between the gross seasonal characteristics of fo Es occurrence with those expected from a simple model of the wind shear mechanism shows similar latitude trends, though the model predicts autumn equinox values which are too low.
Total Ionisation Cross Sections in e??H(2S) Scattering
Authors: Mukherjee KK , Basu Choudhury Keka , Ranjit Singh N , Mazumdar PS , Brajamani S
Published: June 2013

Total cross sections for the electron impact ionisation from the 2S state of atomic hydrogen have been calculated in the energy range 5 �1-68 eV of the incident electron by using a rigorous distorted wave method in which the effects of both the initial and final channel distortions are taken into account. The present results show improved agreement with experimental findings in comparison with other theoretical predictions.
Double-cyclotron Absorption: A Semiclassical Formulation
Authors: Ball LT , Melrose DB
Published: June 2013

A general semiclassical formulation of the process where charged particles in a magnetized plasma simultaneously emit or absorb two gyromagnetic waves is presented. The kinetic equations. which describe the evolution of the wave number and of the particle distribution number due to these processes, are given. General expressions for the probability of double-cyclotron absorption are derived.
A Dielectric Approach to High Temperature Superconductivity
Authors: Mahanty J , Das MP
Published: June 2013

In this paper we investigate the dielectric response of an electron-ion system to the presence of a pair of charges. From the nature of the dielectric function, it Is shown that a strong attractive pair formation is possible depending on the dispersion of the ion branches. The latter brings a reduction to the sound velocity which is used as a criterion for the superconductivity. By solving the BCS equation with the above dielectric function, we obtain a reasonable value of Te.