bluuebunny/crossref_metadata_2025 huggingface dataset:
SQUID Magnetometer for Mangetization Measurements
Authors: K Gramm  , L Lundgren  , O Beckman
Published: January 2007

A magnetometer using a symmetric rf-biased SQUID (Superconducting quantum interference device) is described. The instrument has been designed for magnetization measurements of small single crystals at low magnetic fields in the temperature range 4.2-400 K. At low temperatures the sensitivity in magnetic moments is 2 × 10-12 Am2 or 2 × 10-9 emu, which is equivalent to Δχ = 10-7 SI with sample volume 3 mm3 at 0.01 T (100 Oe).
The27Al(d, nγ) Reaction and Bound Isobaric Analogue States in28Si
Authors: J Lyttkens  , I Bergqvist  , G Lodin  , L Nilsson
Published: January 2007

The27Al(d,nγ)28Si reaction has been used to study characteristics of bound isobaric analogue levels in28Si. Neutron energies were determined by time-of-flight techniques using a pulsed incident beam and a large liquid scintillation detector. The neutron detector was placed at 0° thus accentuatinglp= 0 transfer. Gamma rays in coincidence with neutrons were detected by a coaxial Ge(Li) spectrometer. The results show good agreement with previously measured branching ratios for the 6 277, 8 589, 9 316 and 9 381 keV levels in28Si. New information is obtained for the analogue of the 2 139 keV level in28Al. The excitation energy is found to be 11 434.1 ± 0.7 keV and gamma-ray transitions are observed toT= 0 as well asT= 1 levels. An upper limit for the lifetime of 100 fs is estimated from the experimental results.
The6,7Li(p, d) Reaction at 185 MeV
Authors: B Fagerström  , J Källne  , O Sundberg  , G Tibell
Published: January 2007

Deuteron spectra have been measured for (p,d) reactions in6Li and7Li for angles between 2.5° and 30° (lab). In the studied separation energy range, ES< 40 MeV, two groups of peaks appeared, separated by 15 to 20 MeV. They were associated with 1pand 1spickup, respectively. Spectroscopic factors were extracted from a DWBA analysis and were found to be compatible with the expectations of the shell model. The position of a broad peak in the 1sregion of the spectra varies with the momentum transfer so as to indicate quasi-free pickup from an α-particle in the target nucleus.
Comment on the Phonon Cranking model
Authors: A N Mantri
Published: January 2007

The energy equations in the phonon cranking model of Fogel et al. are shown to be equivalent to those in the centrifugal stretching model. The two models are found to differ, however, in their predictions regarding information about the nuclear shape in the excited states as discussed in the text.
Lifetime Measurements in Cu I and Cu II
Authors: L J Curtis  , B Engman  , I Martinson
Published: January 2007

Using 180-330 keV Cu+ions we have studied the beam-foil spectrum of Cu (1 000-6 000 Å) and determined lifetimes for four excited terms in Cu I and one in Cu II.
The Spectrum of Five-Times-Ionized Vanadium
Authors: Jan Olof Ekberg
Published: January 2007

The spectrum of five-times-ionized vanadium, V VI, has been observed from 110 Å to 2 000 Å by using a vacuum sliding-spark discharge and a 5-m grazing-incidence spectrograph and a 3-m normal-incidence spectrograph. About 170 lines have been identified as combinations between 56 levels in the 3s23p6, 3s23p53d, 4s, 4p, 4d, 4f, 5sand 3s3p63dconfigurations. The energy parameters determined from least-squares fits of the observed level values are compared with Hartree-Fock calculations. The ionization energy, 3s23p52P3/2-3s23p61S0, is determined to 1 033 700 ± 400 cm-1(128.16 ± 0.05 eV).
Nonresonant Wave-coupling and Wave-particle Interactions
Authors: D Anderson
Published: January 2007

We study the interaction between two primary waves and their corresponding nonresonant beatwave. The beatwave is assumed to interact strongly with the plasma particles, thus causing a heating of the plasma and an energy transfer between the primary waves. The process can be interpreted as direct nonlinear interaction between the primary waves and the particles. The results of the general analysis are applied to the phenomenon of beat heating of a plasma by means of two laser beams, and also to the stimulated Compton scattering effect.
Thickness Variations and Lifetimes of Carbon Foils under Nitrogen-ion Bombardment
Authors: P D Dumont  , A E Livingston  , Y Baudinet-Robinet  , G Weber  , L Quaglia
Published: January 2007

The deposition of carbon upon carbon foils and the lifetimes of foils during bombardment by nitrogen ions have been investigated under various experimental conditions. The rate of carbon deposition depends upon the energy and current density of the bombarding ions, as well as upon the condition of vacuum. For ion energies of 0.125-1.5 MeV/atom and current densities of 0.25-13.0 μA/cm2, increases in areal density of up to 40% for ≃ 10 μg/cm2foils have been observed under conditions typically employed in nuclear physics and beam-foil spectroscopy. The source of the deposited carbon appears to be carbon-containing molecules in the residual gas of the vacuum system. Elimination of carbon deposition has been achieved by surrounding the foil with a cooled baffle. The lifetime of the foil (time until breakage) is found to be, at a given energy per atom, the time required for a constant number of atoms to have bombarded the foil.
Observations of a Regular Void Array in Natural Fluorite Irradiated with 100 keV Electrons
Authors: L T Chadderton  , E Johnson  , T Wohlenberg
Published: January 2007

Transmission electron microscopy observations of saturated electron radiation damage in natural fluorite crystals are briefly described. The damage takes the form of a superlattice array of defects presenting a contrast typical of voids. The void superlattice is simple cubic.
The Nucleon Source Spectrum Generating the Muon Component and Expected Coupling Function for an Inclined Meson Telescope
Authors: K Åström
Published: January 2007

In the analysis of data from ground-based muon telescopes the nucleon spectrum in the upper atmosphere has to be known better than can be found from existing direct measurements. Therefore we have made an indirect determination of this spectrum. In a test of the reliability of our approach we have been able to reproduce muon spectra within experimental limits in at least the 0.2-50 GeV/c interval and at 0-60° to the zenith direction, at different atmospheric depths and geomagnetic latitudes. A calculation of the muon pressure coefficient for a standard cube gave -0.16% mb-1for high latitudes. In order to get some information on the angular distribution of the nucleons we have reexamined the applicability of the Gross transformation. For that purpose we have also made a fundamental study of a three-dimensional cascade. In a very simplified model we have assumed that the nucleons are isotropically produced in theLS. A linear cascade does not reflect the nucleon transport from one direction to another. Thus an exponential law for the nucleons in the atmosphere will not be obtained. The nucleon spectrum is discussed mainly in terms of the attenuation mean free pathLN: In order to meet the rather stringent conditions imposed by the muon spectra as a whole it was necessary to putLN= 160 gcm-2in the upper atmosphere. This astonishingly high value is nevertheless compatible with existing data on the nucleon component. We have found a linear cascade approximation to be useful in the derivation of the muon monitor coupling functions. The expected coupling function for an inclined meson telescope with a zenith angle of 35° is given.
On the Corrections to the Glauber Approximation
Authors: A M Din
Published: January 2007

We propose to study a systematic eikonal expansion within non-relativistic potential scattering in which the lowest order term is equivalent to the Glauber approximation. The range of validity of this approximation is discussed in terms of the general structure of the higher order correction terms of the expansion scheme.
Investigation of Clustering Effects in the Reaction pp → ppπ+π+π-π-at 19 GeV/c
Authors: J Allan  , G Blomqvist
Published: January 2007

Possible production of high multiplicity clusters of secondaries in the reaction pp → ppπ+π+π-π-at 19 GeV/c is investigated. The experimental distribution of dispersion versus mean for the pion rapidities shows, compared to simple one-component models, an excess of events in the regions where a single diffraction dissociation process is expected to populate. A method based on the Cramér von Mises statistical test combined with an operational method for selection of quasi two-body reactions is used for investigation of clustering effects in phase space caused by different reaction mechanisms. The analysis indicates that the distribution of experimental events in phase space has mainly two population centers, one consisting of events with the kinematical configuration expected from a single diffraction dissociation process. Results from application of various methods for selection of quasi two-body reactions are compared with similar investigations at other incoming momenta. A comparison with the reactions π±p → pπ±π+π+π-π-at 16 GeV/c shows that the samples of single diffraction-like events fulfil the factorization property.
The Spectrum of Doubly Ionized Barium, Ba III
Authors: Peter Hellentin
Published: January 2007

About 480 Ba III lines have been identified in the 10 800-400 Å range. The spectrum was emitted from a sliding spark discharge. 53 even and 58 odd energy levels have been established, including all levels of the 5p55g, and parts of the 6gand 6hconfigurations. The 4forbits show the contraction characteristic of the rare earths. Configuration interaction giving rise tos-fandp-gtransitions have been observed. The2P3/2series limit is determined to be 289 100 ± 20 cm-1.
Spectrum of Trebly-Ionized Strontium (Sr IV)
Authors: Jørgen E Hansen  , Willy Persson
Published: January 2007

The spectrum of Sr IV emitted from a sliding spark has been studied. The previous analysis has been revised and greatly extended. About 570 lines in the range 6 000 Å to 250 Å have been identified as combinations between 23 odd levels belonging to the 4s24p5and 4s24p45pconfigurations and 72 even levels belonging to the 4s4p6, 4s24p45s, 6s, 4dand 5dconfigurations. Only one level, (1D)4d2G9/2, remains unidentified in these configurations whereas only seven of the levels were known previously. The configurations have been interpreted theoretically with configuration interaction effects included. The energy parameters determined in least-squares fits to the observed energy-level values are compared with Hartree-Fock values. The eigenvectors obtained in the least-squares fitting are used to calculategfvalues for the transitions to the ground term from the even configurations. These are compared to the observed intensities. The ionization energy is estimated to be 453 800 ± 2 000 cm-1(56.3 ± 0.2 eV). Calculated wavelengths of 85 lines in the 560 Å to 264 Å range are proposed as reference wavelengths.
Les niveaux 4f11(4I15/2) 5d, 6p de l'holmium une fois ionisé (Ho II)
Authors: Nissan Spector
Published: January 2007

The two entire structures of the 10 odd levels 4f11(4I15/2)5dand 6 even levels 4f11(4I15/2)6pof Ho II have been established. Forty infrared lines are classified. The following values for the spin-orbit parameters have been obtained directly from the two structures based on their evidentJ-jcharacter:

ζ5d= 802 cm-1, ζ6p= 2 118 cm-1
Polarization in the Inelastic Scattering of 185 MeV Protons from27Al
Authors: A Ingemarsson  , A Hallgren  , O Jonsson
Published: January 2007

The polarization of 185 MeV protons in the excitation of the states at 2.21 and 2.98 MeV in27Al has been measured in the angular region 7.5°-40°. The results are found to be rather similar to those obtained for low-lying collective 2+levels in even-even nuclei.
A Numerical Calculation of Electron States in a Two-dimensional Simple Square Model Crystal including an Edge Dislocation
Authors: Sune Marklund
Published: January 2007

The qualitative features of the changes in the electronic structure of a square array of atoms, when an edge dislocation type of disorder is present are, investigated within the framework of the Hückel method.
Level Structure and Transition Probabilities in165Tm and167Tm
Authors: L-G Svensson  , H Solhed  , N-G Jonsson  , S M Darwish  , J Lindskog
Published: January 2007

Transitions in165Tm and167Tm have been studied by means of the (p,nγ) and (p,2nγ) reactions. Singles gamma-ray spectra, gamma-gamma coincidences and conversion electron spectra have been recorded. The level schemes of both isotopes have partly been verified and new members of the 1/2-[541] band have been found in167Tm. The halflives of three levels in the ground state bands have been measured using an electron-electron coincidence spectrometer:T1/2= 322 ± 20 ps for theI= 7/2 level in165Tm,T1/2= 343 ± 15 ps for theI= 7/2 level in167Tm andT1/2= 66 ± 7 ps for theI= 5/2 level in167Tm. The electric and magnetic moments have been compared for the odd thulium isotopes. It was also shown that the quadrupole deformation ϵ2is constant and that the systematics of the single particle states in these isotopes only may be explained by variations of the hexadecapole deformation, ϵ4of the nuclear shape.
The Negative Parity Levels in 55Mn via Coulomb Excitation
Authors: R G Kulkarni
Published: January 2007

The excited levels of 55Mn up to 2 200 keV were studied by means of Coulomb excitation of 55Mn with 4He ions varying in energy from 5 to 8 MeV. The yields of gamma-rays were measured with a Ge(Li) detector. New levels in 55Mn at 1 293 and 2 016 keV were observed. Gamma-ray angular distribution measurements established spin values of 1/2 and 5/2 or 7/2 for the 1 293 and 2 016 keV states, respectively. The E2 and M1 reduced transition probabilities were determined for the eight excited states and these results were compared with the theoretical calculations of unified model.
Hyperfine Structure of175Lu and Nuclear Electromagnetic Moments of the Lutetium Isotopes161-181Lu
Authors: C Ekström
Published: January 2007

The electronic parts of the dipole and quadrupole hyperfine structure interactions in175Lu are evaluated from the known values of the hyperfine constants and the nuclear moments. A comparison is made with results obtained from atomic Hartree-Fock calculations including relativistic and polarization effects. Furthermore, experimental nuclear spins and (recalculated) moments of lutetium isotopes are compared with results from Nilsson model calculations.
Transition Potential Models for Auger Electron Spectra
Authors: H Siegbahn  , O Goscinski
Published: January 2007

Three models for predicting chemical shifts of Auger electron lines are presented. A relation between binding energy chemical shifts and Auger shifts is deduced. The difference in relaxation energy between the Auger and ordinary photoionization process is explicitly included in the analysis. Ambiguities in the use of equivalent cores potential models are pointed out and removed. Computational schemes are proposed and illustrated.
Vibrational and Vibronic Structure in the Valence Electron Spectrum of H2S
Authors: Leif Karlsson  , Lars Mattsson  , Reinhard Jadrny  , Torsten Bergmark  , Kai Siegbahn
Published: January 2007

The high resolution HeI induced electron spectrum of H2S is presented and the energies of the observed vibrational and vibronic bands are reported. In the2B1electron band two progressions of vibrational bands have been measured. In the2A1electron band the vibronic structure associated withv2bending vibrations has been partially resolved. Assignments of the vibronic bands are suggested from a comparison with electronic emission data in terms of the vibrational and angular momentum quantum numbersv2andK.
The Spectrum of Four-Times-Ionized Titanium, TiV
Authors: Lars Åke Svensson
Published: January 2007

By means of a 3-m normal-incidence spectrograph the following transitions of Ti V have been observed: 3d-4p(66 lines in the region 440-580 Å), 4s-4p(27 lines, 1 250-2 400 Å), 4p-5s(19 lines, 800-1 000 Å), 4p-4d(52 lines, 1 000-1 500 Å). In addition, the configuration 3s3p63d, which is highly mixed with 4p, has been determined by 64 combinations with 3d, 4s, 4dand 5s. Energy parameters are derived from least-squares fits of observed levels and compared to Hartree-Fock calculations. By an isoelectronic extrapolation the ionization energy is found to be 800 550 ± 200 cm-1.
The Fe I Spectrum in the Region 1-4 μm
Authors: U Litzén  , J Vergès
Published: January 2007

The Fe I spectrum has been investigated in the region 1-4 μm with one of the Fourier Transform Spectrometers at Laboratoire Aimé Cotton, Orsay. The line list contains 374 lines, most of them measured with an accuracy better than 5 × 10-3cm-1. A comparison with the solar spectrum confirms many previous identifications and gives about 100 new identifications of solar lines as due to Fe I.
The Spectrum of Six-Times-Ionized Chromium, Cr VII
Authors: Jan Olof Ekberg
Published: January 2007

The spectrum of six-times-ionized chromium, Cr VII, has been observed from 90 Å to 2 000 Å by using a 5-m grazing-incidence spectrograph and a 3-m normal-incidence spectrograph. The light source was either an open vacuum spark or a vacuum sliding spark. About 135 lines have been identified as combinations between 60 levels in the configurations 3s23p6, 3s23p53d, 4s, 4p, 4d, 4f, 5s, 5dand 6sas well as 3s3p63dand 3s3p64p. The energy parameters determined from least-squares fits of the observed level values are compared with Hartree-Fock calculations. The ionization energy, 3s23p52P3/2-3s23p61S0, is determined to 1 291 900 ± 600 cm-1(160.17 ± 0.07 eV).
On the Axially Symmetric Equilibrium of a Magnetically Confined Plasma
Authors: B Lehnert
Published: January 2007

The axially symmetric equilibrium of a magnetically confined plasma is reconsidered, with the special purpose of studying high-beta schemes with a purely poloidal magnetic field. A number of special solutions of the pressure and magnetic flux functions are shown to exist.
Low Temperature Spin-lattice Relaxation of Protons in Solid Ammonium Hexachloroplumbate
Authors: J E Tuohi  , E E Ylinen  , M Punkkinen
Published: January 2007

Nuclear spin-lattice relaxation times T
1 for protons in polycrystalline (NH4)2PbCl6 were measured by the NMR pulse method from room temperature to liquid helium temperature at the resonance frequencies 9, 22, and 42 MHz. A minimum in T
1 caused by the classical reorientation motion of the NH4
+-ion was observed at about 70 K. Parameters of the reorientational motion were deduced from the T
1 data above 60 K. Additional T
1 minima were observed below 60 K. They were interpreted in terms of the temperature dependent effective tunneling splitting of the torsional ground state of the ammonium ion.
Five-meson VDM Fits to the Nucleon Form Factors
Authors: S Mehrotra  , M Roos
Published: January 2007

Nucleon electromagnetic form factor data in the spacelike and the timelike regions are fitted with a VDM sum of (up to five) isovector and isoscalar pole terms. Finite width effects are included in the ρ and the ρ' terms. The effects of including the ρ' and the ψ(3.1) are studied. We only find good fits when the ρ' is allowed to have a too low mass (1.2-1.4 GeV) and when in addition some of the couplings or other derived quantities disagree with other estimates. We conclude that VDM is unable to describe the data unless one introduces a number of yet unknown mesons, such as ω', ϕ', ρ' (1.2), etc.
High Resolution Lifetime Studies of the d3Πg, C1Πgand D1Σu+States in C2with Applications to Estimates of the Solar Carbon Abundance
Authors: L Curtis  , B Engman  , P Erman
Published: January 2007

Lifetimes have been measured for a number of vibrational levels of thed3Πg,C1ΠgandD1Σu+states in the C2molecule using the High Frequency Deflection technique. Particular attention was paid to various rotational levels of thev' = 6 level of thed3Πgstate but no decrease in lifetime was found indicating the absence of earlier suggested predissociation effects, which would be an explanation of the occurrence of the high-pressure carbon bands. For thed-a(Swan) bands oscillator strengths are found which are considerably higher than earlier estimates demanding a 40% decrease in the estimate of the solar carbon abundance.
The Spectrum of CuO. Rotational Analysis of Some Blue and Violet Bands
Authors: O Appelblad  , A Lagerqvist
Published: January 2007

Four new band systems of the emission spectrum of CuO have been rotationally analyzed, namely theE2Δ-X2Πi,H2Π-X2Πi,I2Π-X2ΠiandP2Π-X2Πisystems. Perturbations in the excited states are discussed. Molecular constants of the new states are given.
Analysis of the 2p53s, 3p, 3d and 4s Configurations of Quadruply Ionized Silicon (Si V)
Authors: Wan-Ü Lydia Brillet
Published: January 2007

The spectrum of quadruply ionized silicon (Si V) was observed between 500 and 1 735 Å. About ninety new lines have been identified as transitions between the 2p53s, 3p, 3dand 4sconfigurations. Energies and designations are given for all these configurations. The ground-term transitions have been remeasured (90-118 Å). The experimental results are supported by parametric calculations and isoelectronic comparison.
An Experimental Study of 3s23pkand 3s3pk+1in the CI I, S I, P I, Si I, and AI I Isoelectronic Sequences
Authors: Rikard Smitt  , Lars Åke Svensson  , Michael Outred
Published: January 2007

New measurements and identifications of the transitions 3s23pk-3s3pk+1have been made in the spectra of S IV, K IV-VII, Ca V-VIII, Sc VI-IX, Ti VII-X, V VII-XI, Cr VIII-XI, Mn IX-XI, and Fe X, XI. The energy parameters of the ground configurations have been determined and expressed as functions ofZby semi-empirical formulae in the S I, P I, Si I, and Al I isoelectronic sequences. Predicted wavelengths for some 150 forbidden lines of astrophysical interest are tabulated.
A Study of the Beam-Foil Excitation Mechanism Using 30-300 keV He+Projectiles
Authors: B Dynefors  , I Martinson  , E Veje
Published: January 2007

Beam-foil excitation functions have been measured for some optical transitions in neutral He (singly as well as doubly excited) and ionized He in the projectile energy range 30-300 keV. The excitation functions have been converted into relative population functions, which for levels within individual level schemes are proportional. The three sets of population functions have been linked by two parameters, one accounting for Rydberg states, and the other accounting for 1s core vacancies. The two empirically determined parameters reproduce also charge state distribution data as well as an absolute beam-foil population measurement.

The relative level populations have been measured for thend3DRydberg series,n⩽ 11, at 100 keV and at 200 keV and found to be asymptotically close to ann-3behaviour.

A search for optical observation of radiative electron capture was performed at 100 keV and 200 keV, the result being negative.
Stabilization of Localized Modes in Plasmas Confined in Poloidal Magnetic Fields
Authors: T Hellsten
Published: January 2007

The plasma contained in a "Spherator" system with a pure poloidal magnetic field and a surrounding gas blanket can be made absolutely stable against magnetohydrodynamic perturbations in the low-β limit. This situation can even be achieved for a sufficiently high ratio between the pressures in the thermonuclear region and the cold boundary region to satisfy reactor conditions, provided that the outer plasma boundary is chosen close to a separatrix.
On the Stabilization of Flute-type Disturbances in a Magnetized Plasma
Authors: B Lehnert
Published: January 2007

Flute-type disturbances are investigated by normal mode analysis in the case of a low-beta plasma being confined in the field from a straight line current. A dispersion relation and stability criterion are derived including the joint effects of the plasma pressure, the finite ion Larmor radius and frequency, and of an imposed radial gravitation field. The results, which may also illustrate the general plasma behaviour in more complicated field geometries, indicate that the stability domain is enlarged substantially by finite Larmor radius effects, especially for small-scale disturbances. Also the centrifugal force in rotating plasmas should have a stabilizing effect under certain conditions. In combination with the stabilizing mechanisms in the boundary regions of impermeable plasmas, the present results provide an alternative to the method of minimum-average-Bstabilization.
Erratum for "Five-meson VDM Fits to the Nucleon Form Factors", S. Mehrotra and M. Roos, Physica Scripta 13, 265 (1976)
Authors: S Mehrotra  , M Roos
Published: January 2007

By mistake the following errors appeared in this paper:

Page 265, equation (2): F11should read F1/21;

Page 269, the reference list in this erratum is to be added.
Measurements on the Differential Cross Section of the π° - Photoproduction on Hydrogen
Authors: S Almehed  , G von Dardel  , G Jarlskog  , L Jönsson  , B Lörstad  , J Palmer  , R Petersen  , L Svensson
Published: January 2007

The differential cross section for photoproduction of π° on hydrogen has been measured in a photon energy range of 560-690 MeV and for production angles in the interval 90°-105° in the centre of mass system. The experiment detects the recoil proton and a π°-decay photon in coincidence, using optical spark chambers and a lead glass Cerenkov counter. Presented cross sections, based on 35 000 events recorded on film, are in good agreement with recent phase shift analysis.
Interactions of 2 GeV/Nucleon16O with Light and Heavy Emulsion Nuclei
Authors: B Jakobsson  , R Kullberg
Published: January 2007

Heavy ion interactions in nuclear emulsions induced by 2 GeV/nucleon16O have been studied. The reaction cross sections determined are 337-85+56mb, 1007-174+175mb and 2180-231+304mb for interactions with H, CNO and AgBr, respectively. Energy-, angular- and transverse momentum distributions of non-relativistic protons (E400 MeV) and all He nuclei have been analysed. Statistical models assuming small correlations among nucleon momenta can account for the main part of the He emission. The energy- and transverse momentum distributions of protons, emitted from light as well as heavy target nuclei indicate that intranuclear nucleon-nucleon scattering is the most important proton emission process. The angular distributions of both high energy protons and high energy He nuclei emitted from the target nucleus differ considerably in central and peripheral16O-AgBr interactions. In order to explain the angular distributions of high energy protons and He nuclei in events with extremely small impact parameter, non-statistical phenomena, possibly hydrodynamic shock wave emission, must be considered.
A Unified Phenomenological Description of Quadrupole Excitations in Even-Even Nuclei
Authors: P O Lipas  , P Haapakoski  , T Honkaranta
Published: January 2007

A phenomenological model is developed for the collective quadrupole properties of all even-even nuclei. Rotational. vibrational and transitional nuclei are included in the model on an equal footing. A Bohr-type intrinsic Hamiltonian for harmonic quadrupole vibrations about an axially deformed shape is solved exactly. States of good angular momentum are projected out of the intrinsic states, and they are made orthogonal by a Schmidt scheme. The angular-momentum and phonon-number composition of the states is analyzed at various stages; states withK= 1 are found spurious. Excitation energies for the ground, β, and γ bands are calculated as expectation values of a radically simplified nuclear Hamiltonian in our projected and orthogonalized states. With increasing deformation the calculated energies evolve smoothly from the evenly spaced phonon spectrum to the Bohr-Mottelson rotational-vibrational spectrum according to the scheme of Sheline and Sakai. Our basic model contains only two parameters (deformationdand energy scale) to fix the entire quadrupole spectrum of a nucleus. Our results are given in the form of graphs suitable for immediate application; numerical results are readily produced by our computer code. The ground bands are fitted comparably to the VMI model, while the β and γ bands are reproduced qualitatively. The nuclei152Sm,152Gd, and114Cd are used as test cases. Quadrupole moments and E2 transition rates are also calculated. Intraground-band transition ratios and branching ratios from the β and γ bands are given in terms of the single parameterd. The results are applied to152Sm with fair success. Finally we extend the model to include two more parameters (anisotropy). The improvement over the basic model is modest in view of the added parameters and computational effort.
Hyperfine Interaction, Zeeman and Stark Effects for Excited States in Rubidium
Authors: G Belin  , L Holmgren  , S Svanberg
Published: January 2007

Highly excitedPandDstates in87Rb were examined using a two-step excitation procedure. A conventional rf lamp and a CW dye laser were used for the first and second step, respectively. The following results for the magnetic dipole interaction constanta, the electric quadrupole interaction constantb, the LandégJfactor, and the tensor polarizability α2were obtained in level-crossing and optical-double-resonance experiments:

92P3/2:a= 4.05(3) MHz,b=0.55(3) MHz,gJ= 1.3335(15)

102P3/2:a= 2.60(8) MHz,gJ= 1.3332(20)

82D3/2:a= 2.840(15) MHz,b= 0.17(2) MHz

82D5/2:a= -1.20(15) MHz,gJ= 1.1998(15)

92D3/2:a= 1.900(10) MHz,b= 0.11(3) MHz

92D5/2:a= (-)0.80(15) MHz,gJ= 1.1995(15), α2= 180.3(9.0) MHz/(kV/cm)2

Many-body calculations of the hyperfine structure of Rb have been performed. The polarization effect is included to all orders, whereas the correlation effect is omitted. The negativeafactors for the2D5/2states, indicating large perturbations, are explained by the polarization contribution. A review of experimental hyperfine interaction constants, LandégJfactors and tensor polarizabilities for rubidium is given together with theoretical values of theafactors. The quadrupole moment for87Rb is obtained from thebfactors for the2P3/2and2D3/2states, using quadrupole parameters from the many-body calculations. The correlation effect is included in a semi-empirical way.
Lifetimes of the 26 099 cm-1and 29 973 cm-1Levels in Er II
Authors: B Engman  , J O Stoner Jr  , I Martinson  , N-E Cerne
Published: January 2007

We report lifetime measurements for two levels in Er II by the beam-foil method. Decay rates were measured for two lines from the 26 099 cm-1level, 3 830 and 3 896 Å, and one line from the 29 973 cm-1level, 3 385 Å. The results are τ = 14 ± 3 ns (3 830 Å), τ = 15 ± 3 ns (3 896 Å), and τ = 9 ± 1 ns (3 385 Å).
Beam-foil Study of Nitrogen in the Vacuum Ultraviolet
Authors: P D Dumont  , Y Baudinet-Robinet  , A E Livingston
Published: January 2007

Beam-foil spectra of nitrogen have been studied in the wavelength region 280-1 230 Å, employing linewidths of about 0.7 Å. Lifetime measurements have been performed for 28 terms in N II-N VI and new classifications have been proposed in N II, III, and V. Where comparison with previous results is possible, good agreement is generally found with the most recent beam-foil determinations or with configuration-interaction calculations. For seven terms there exist no previous experimental or theoretical results.
K-LL Auger Spectrum of Aluminium
Authors: G Dufour  , J-M Mariot  , P-E Nilsson-Jatko  , R C Karnatak
Published: January 2007

Detailed K-LL Auger spectra of aluminium metal obtained either by X-ray excitation or electron bombardment are presented. Both spectra, which are rich in plasmon peaks, are very similar. The experimental energies are in close agreement with calculations in which two-hole coupling and relaxation effects are taken into account.
Kinetic Analysis of the Resonant Three-wave Coupling in Weakly Dissipative Plasmas
Authors: R Jancel
Published: January 2007

This paper presents a general perturbation method for the kinetic analysis of the role played by the dissipative effects in non-linear wave-wave interactions. The "third order" collisional contributions to coupling coefficients are thus rigorously calculated for a weakly ionized medium and for the resonant three-wave coupling, and it is shown how these results can be extended to other physical models and to other types of wave-wave interaction.
A Torque Magnetometer with Proportional-Integrating-Differentiating (PID) Compensation
Authors: Björn Westerstrandh  , Uno Gäfvert  , Leif Lundgren
Published: January 2007

A magnetometer for measuring torques in the range 10-10Nm -5·10-4Nm (10-3dyncm -5·103dyncm) is described. Torque compensation is achieved by feedback from a photodetector into a PID regulator system which generates a current through a compensation coil located in the field of permanent magnets. Stability criteria for the regulator system are discussed. The apparatus permits continuous measurement of the torque as a function of angle with simultanuous registration of the data on x-y-recorder and on paper tape for computer analysis. Measurements can be made in the temperature range 4.2 K to 400 K.
Uniqueness of Fixed Momentum Transfer Amplitudes Derived from Data
Authors: Esko Pietarinen
Published: January 2007

The determination of fixedtamplitudes is mathematically similar to the N/D-problem for partial wave amplitudes. It is shown that the kernel of the resulting integral equation can be divided into two parts, one of which gives a compact operator and the other being invertible by the Neumann series. Given one solution it is shown that all other solutions can be explicitly constructed.
The Large-Distance Behaviour of the Virtual Delbrück Effect
Authors: Paul Papatzacos
Published: January 2007

It is found that, when the distance from a nucleus is large compared to the electron Compton wave length, the virtual Delbrück effect is equivalent to a potential. The analytic expression for this potential is given in coordinate space. An expression is found for the electric polarizability of the vacuum around a charged point particle.
Local Loop Dominance in the Dual Unitarity Scheme
Authors: J Dias de Deus  , I Uschersohn
Published: January 2007

The unitary equation in the dual approach can be written as a sum over reggeon loop diagrams. We assume that in some definite regions in energy, only one diagram, with a definite number of loops dominates the sum. As consequences we obtain SU(M) symmetry for coupling constants, Gell-Mann Okubo formulae for mass breaking and exchange degeneracy for reggeon trajectories. We also derive relations connecting the Pomeron and reggeon intercepts with quantities referring to production of clusters. Predictions are given for the breaking of Pomeron couplings in reactions involving strange and charmed particles.
55Co Level Properties
Authors: G Lodin  , L Nilsson  , B Erlandsson  , J Lyttkens
Published: January 2007

The decay of low-lying levels in55Co has been studied by means of the54Fe(d,nγ)55Co reaction. Neutron energies were determined by time-of-flight techniques using a pulsed incident beam and a large liquid scintillator. Gamma rays in coincidence with neutrons were detected by a Ge(Li) spectrometer. Three levels at 4 720.8 ± 0.6 4 747.1 ± 0.6 and 5 172.4 ± 0.6 keV were strongly populated. The 4 721 and 5 172 keV levels have earlier been identified as the isobaric analogues of the55Fe ground state and first excited state. On the basis of a comparison of the present results with previous particletransfer reaction studies it is suggested that the ground state analogue is split into the 4 721 and 4 747 keV levels. A study of excitation functions of54Fe(d,n) transitions at incident deuteron energies between 5.0 and 6.0 MeV shows that the spectroscopic strengths obtained from (d,n) experiments in this mass region at these energies depend strongly on the incident energy.
The Na I-like Spectra of Potassium and Calcium, KIX and CaX
Authors: Bengt Edlén  , Erik Bodén
Published: January 2007

From about 50 observed lines, in the range from 60 to 600 Å, in each of the spectra K IX and Ca X, term values are obtained forns, np, ndandnfup to highn-values. The series are perfectly regular and expressed by Ritz formulae which permit their extension to arbitraryn-values. The ionization limits are determined by means of an isoelectronically extrapolated polarization formula applied to thenfseries with the result:El(K IX) = 1 418 058 ± 20 cm-1andEl(Ca X) = 1 704 054±30 cm-1. We give, also, complete lists of the potassium and calcium lines of different ionization stages measured on our spectrograms, obtained with a 5-m grazing-incidence spectrograph and a condensed vacuum spark. The potassium list contains 230 lines from 230 to 41 Å, about half of which have been classified in the spectra from K VII to K XII. The corresponding figures for calcium are 294 lines from 217 to 35 Å of Ca VII to Ca XIII. The uncertainty in the wavelengths is estimated to be less than 0.005 Å.
Hyperfine Interaction, Zeeman and Stark Effects for Excited States in Cesium
Authors: G Belin  , L Holmgren  , S Svanberg
Published: January 2007

Our previous measurements in thePandDseries in133Cs have been extended to a number of higher lying levels, populated in a two-step excitation process involving an rf lamp and a CW dye laser. TheDstates were studied with the level-crossing technique, while the optical-double-resonance method was used for the investigation of thePstates. For the magnetic dipole interaction constanta, the LandégJfactor, and the tensor polarizability α2we obtain

122P3/2:a= 1.10(3) MHz,gJ= 1.3340(15)

132P3/2:a= 0.77(5) MHz,gJ= 1.3337(20)

72D3/2: |a| = 7.4(2) MHz

142D3/2: |a| = 0.425(7) MHz

152D3/2: |a| = 0.325(8) MHz

162D3/2: |a| = 0.255(12) MHz

172D3/2: |a| = 0.190(12) MHz

182D3/2: |a| = 0.160(10) MHz

132D5/2: α2= 19(1) GHz/(kV/cm)2

142D5/2: α2= 37(2) GHz/(kV/cm)2

152D5/2: α2= 70(4) GHz/(kV/cm)2

162D5/2: α2= 120(6) GHz/(kV/cm)2

172D5/2: α2= 199(10) GHz/(kV/cm)2

182D5/2: α2= 323(16) GHz/(kV/cm)2

Ab initio calculations of many-body perturbation type, including polarization effects to all orders, have been performed in order to obtain theoretical values of the hyperfine structure constants. The resultingafactors are listed together with the corresponding experimental values for mostS, P, andDstates in133Cs measured so far. The discrepancy between the experimental and theoretical values is mainly due to the omission of the correlation effect, which is essentially as important as the polarization effect. Still, for theDstates the polarization effect is large enough to yield negative values for all the2D5/2states, which is in accordance with the experimental results. Semiempirical values of theafactors have also been obtained using the Fermi-Segré-Goudsmit formula, and the results are compared with the experimental values. The measured values of α2agree well with values calculated with the Coulomb approximation due to Bates and Damgaard.
Radiative Lifetimes of Resonance Levels in Fel I and Fe II
Authors: J Brzozowski  , P Erman  , M Lyyra  , Wm Hayden-Smith
Published: January 2007

Lifetimes of variousJ-levels of low lying resonance levels in Fe I and Fe II have been measured at high spectral resolution using the High Frequency Deflection technique. The results are compared with earlier results and recommended multipletf-values are given for astrophysical abundance determinations.
Direct Measurement of the N2+C State Predissociation Probability
Authors: Peter Erman
Published: January 2007

The lifetimes of the vibrational ν = 1-5 levels of the N2+C state have been directly measured at high resolution using the High Frequency Deflection technique. For the ν = 2 level, a radiative lifetime τ = 78.9 ± 3.0 ns is obtained, while the lifetimes drop sharply to a constant value of 4-5 ns for the ν ⩾ 3 levels. Since the ν ⩾ 3 levels are all above the lowest dissociation limit, the measurements confirm that these levels are predissociated and at a rate of about 2 × 108s-1. The lifetime variation suggests that the predissociation mainly takes place through vibrational coupling with theBstate.
Core Level and Band Structure Energies of the Alkali Halides LiF, LiCl and LiBr Studied by ESCA
Authors: L I Johansson  , S B M Hagström
Published: January 2007

The ESCA technique has been used to determine the energy difference between the top of the valence band and the outermost core levels in LiF, LiCl and LiBr. The energy differences obtained between the top of the valence band and the Li 1sline in LiF, LiCl and LiBr were respectively 49.8 eV, 53.2 eV and 54.1 eV. These results agree rather well with the predictions of the point charge model including corrections for polarization effects.
The Lower Hybrid Resonance. Its dependence on impurities and ion-Larmor radii in hot TOKAMAK plasmas
Authors: H Wilhelmsson
Published: January 2007

The form of the relation describing the lower-hybrid resonance is examined including its dependence on impurities as well as ion-Larmor radii. For typical TOKAMAK parameters we calculate a shift of the resonance frequency amounting to a decrease by 7% in the case of oxygen (fractional content 4%) and by 5% for carbon (fractional content 4%) and by 2% for molybdenum (fractional content 0.2%) as compared to the hot case without impurities.
The Electron-Phonon Interaction in Normal Metals
Authors: G Grimvall
Published: January 2007

The influence of the electron-phonon many-body renormalization effects on the electron states in normal metals is reviewed. The emphasis is on the electron-phonon mass enhancement parameter λ. The occurrence or absence of renormalization effects is discussed for different electronic properties. After a review of theoretical and experimental methods of obtaining information about λ, numerical values for this quantity are given for the elements. Other sections deal with alloys, compounds, disordered and amorphous metals, anisotropy in λ and variations in λ under pressure. Finally, brief comments are given on the electron-electron and electron-magnon renormalization of the electron mass.
Jahn-Teller Motion in Copper Bromate
Authors: A T Rønning  , I Svare
Published: January 2007

Measurements of ESR line width and spin-lattice relaxation times in pure and Zn-diluted Cu(BrO3)2·6H2O can be fitted to a Jahn-Teller distortion frequency (1/τ) =aT+bT5for the Cu(H2O)62+complexes. The correlation time τ depends strongly upon Cu2+concentration and is about 100 times longer for pure copper bromate than for very diluted salts.
A Microwave Slab Line Cavity for the Excitation of Electrodeless Discharge Tubes
Authors: C B Hammond  , M Outred
Published: January 2007

A new form of microwave cavity, operating at 2.45 GHz, is described for use with electrodeless discharge tubes. The size and electrical operating conditions of the cavity may be changed readily. The second spectrum of helium, neon and argon has been strongly excited, using a sealed low pressure electrodeless discharge tube, in the new cavity.
On Functional Relations between Reduced Distribution Functions and Entropy Production by Non-Hamiltonian Perturbations
Authors: R Dobbertin
Published: January 2007

Functional relations are derived which link the reduced distribution functions of a classicalN-particle system through the entropy production due to microscopic deviations from hamiltonian dynamics. These relations have been used in an earlier paper for the closure of the BBGKY-hierarchy and may be useful for the establishment of collective particle models in particular and the understanding of irreversibility in general.
Vlasov Equation and Entropy
Authors: R Dobbertin
Published: January 2007

A collective, non-hamiltonian model for the dynamics of a classicalN-particle system is given. The Liouville statistics yields a hierarchy for the reduced distribution functions and the model has been chosen in such a way that the first of the hierarchy equations is the Vlasov equation regardless of collisions or correlations. The Gibbs entropy of such a system is not conserved albeit the one particle distribution function is a solution of the reversible Vlasov equation.
Short Tunable Pulses from a Nitrogen-laser-pumped Dye Laser
Authors: S A Borgström
Published: January 2007

Part of the output of a N2-laser, giving 180 kW in 4 ns, was used to pump a dye laser of the Hänsch type, having 0.01 nm bandwidth. The dye laser pulse-shape was found to depend strongly on cavity-round-trip modulation, varying with pumping power and cavity length. By varying the cavity length, pulse widths in the range 1 to 2.5 ns were obtained with peak powers ranging from 0.1 to 1 kW. Increased power and pulse reshaping could be obtained in an amplifier pumped by the remaining output of the N2-laser. Further, some alternative schemes for the generation of short tunable, narrow bandwidth, dye laser pulses are proposed.
The g-Factor of the 31/2--State in209Po
Authors: K-G Rensfelt  , C Roulet  , K Westerberg
Published: January 2007

Using the TDPAD method, theg-factor of the 31/2-core excited isomeric state in209Po populated in thenatPb(α,xn)209Po reaction using 40-51 MeV α-particles has been measured to begcorr(31/2-,209Po)= +0.625 ± 0.005. The configuration of this state has been proposed to be about 85% π(h9/2i13/2)νg9/2(j-2)0+and 15% π(h9/2i13/2)νi13/2-1. Theg-factor indicates that there is, in addition, an admixture of π(h9/2f7/2)νj15/2(j-2)0+.
Radiative Electron Capture by Multiply-Ionized Chlorine Atoms
Authors: J Lindskog  , J Phil  , R Sjödin  , A Marelius  , K Sharma  , R Hallin  , P Lindner
Published: January 2007

Radiative electron capture by highly ionized chlorine atoms passing through solid targets has been studied. The energy and angular distribution of the radiation has been measured as well as the cross-section of the process and its energy dependence. There is shown to be agreement between experimental data and theoretical values obtained from a modified Bethe-Salpeter model.
Thermal Shifts in Energy Level Separations in Some Rubidium and Silver Halides Studied by ESCA
Authors: L I Johansson  , C W B Martinson  , P-E Nilsson-Jatko  , S-E Karlsson  , S B M Hagström
Published: January 2007

Energy level separations and their temperature dependences have been measured for some rubidium and silver halides. The observed thermal shifts agree quite well with the shifts in Madelung energy due to thermal expansion for the outer levels in the rubidium halides and the core levels in RbCl and AgCl. The experimental results on the bromides, however, indicate that differences in repulsive effects between different core levels are significant. The phase transition in AgI at 147°C is shown to influence the energy separation between the Ag 3d and I 3d levels. Valence band results for the silver halides at different temperatures are presented.
Term Analysis of Cr III
Authors: Jan Olof Ekberg
Published: January 2007

The spectrum of doubly ionized chromium, Cr III, has been observed by using a low-voltage sliding-spark discharge. Exposures were made on the 10.7-m normal-incidence vacuum spectrograph at the National Bureau of Standards, Washington, and the 3-m normal-incidence spectrograph at our institute. About 950 lines have been identified in the region 750-2 680 Å as combinations of the type 3d4-3d34pand 3d34s-3d34p, establishing 180 of the 182 possible levels with an estimated uncertainty of less than ±0.3 cm-1. The energy parameters determined from a least-squares fit of the observed level values are compared with Hartree-Fock calculations. From the observed 3d4levels forbidden lines of Cr III are predicted.
The Body Modes of String Instruments
Authors: Karl A Stetson  , Carl-Hugo Ågren
Published: January 2007

A mathematical method is presented for determining the vibration modes of a string instrument from modes obtained from the top and back plates alone. The Rayleigh-Ritz method is employed and is shown to be most practicable when the plate modes are those obtained with the edges of the plates constrained in the same fashion as when glued to the sides of the instrument itself. The effect of a sound post can be dealt with by application of the method of Lagrange multipliers.