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  Subjects -> PHYSICS (Total: 736 journals)
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    - MECHANICS (5 journals)
    - NUCLEAR PHYSICS (28 journals)
    - OPTICS (53 journals)
    - PHYSICS (623 journals)
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PHYSICS (623 journals)            First | 1 2 3 4 5 6 7 | Last

Computational Mathematics and Mathematical Physics     Hybrid Journal   (2 followers)
Computational Science and Discovery     Full-text available via subscription  
Computer Physics Communications     Hybrid Journal  
Contemporary Concepts of Condensed Matter Science     Full-text available via subscription  
Contemporary Physics     Hybrid Journal   (8 followers)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (3 followers)
Contributions to Plasma Physics     Hybrid Journal   (2 followers)
COSPAR Colloquia Series     Full-text available via subscription  
Cryogenics     Hybrid Journal   (11 followers)
Current Applied Physics     Full-text available via subscription   (4 followers)
Diamond and Related Materials     Hybrid Journal   (12 followers)
Differential Equations and Nonlinear Mechanics     Open Access   (4 followers)
Doklady Physics     Hybrid Journal   (2 followers)
Dynamical Properties of Solids     Full-text available via subscription  
ECS Journal of Solid State Science and Technology     Full-text available via subscription  
Egyptian Journal of Remote Sensing and Space Science     Open Access   (4 followers)
Embedded Systems Letters, IEEE     Hybrid Journal   (14 followers)
Energy Procedia     Open Access   (2 followers)
Engineering Failure Analysis     Hybrid Journal   (22 followers)
Engineering Fracture Mechanics     Hybrid Journal   (14 followers)
Environmental Fluid Mechanics     Hybrid Journal   (2 followers)
EPJ Nonlinear Biomedical Physics     Open Access  
EPJ Photovoltaics     Open Access  
EPJ Web of Conferences     Open Access  
European Journal of Mechanics - A/Solids     Hybrid Journal   (2 followers)
European Journal of Mechanics - B/Fluids     Hybrid Journal  
European Journal of Physics     Full-text available via subscription   (5 followers)
European Journal of Physics Education     Open Access   (5 followers)
European Physical Journal - Applied Physics     Full-text available via subscription   (4 followers)
European Physical Journal C     Hybrid Journal  
Europhysics News     Open Access   (1 follower)
Experimental Heat Transfer     Hybrid Journal   (5 followers)
Experimental Mechanics     Hybrid Journal   (15 followers)
Experimental Methods in the Physical Sciences     Full-text available via subscription  
Experimental Techniques     Hybrid Journal   (15 followers)
Exploration Geophysics     Hybrid Journal   (2 followers)
Few-Body Systems     Hybrid Journal  
Fire and Materials     Hybrid Journal   (4 followers)
Flexible Services and Manufacturing Journal     Hybrid Journal   (3 followers)
Fluctuation and Noise Letters     Hybrid Journal   (1 follower)
Fluid Dynamics     Hybrid Journal   (5 followers)
Fluid-Structure Interactions     Full-text available via subscription  
Fortschritte der Physik/Progress of Physics     Hybrid Journal  
Frontiers in Physics     Open Access   (2 followers)
Frontiers of Materials Science     Hybrid Journal   (4 followers)
Frontiers of Physics     Hybrid Journal   (1 follower)
Fusion Engineering and Design     Hybrid Journal   (2 followers)
Geochemistry, Geophysics, Geosystems     Full-text available via subscription   (21 followers)
Geografiska Annaler, Series A: Physical Geography     Hybrid Journal   (3 followers)
Geophysical Research Letters     Full-text available via subscription   (41 followers)
Geoscience and Remote Sensing, IEEE Transactions on     Hybrid Journal   (19 followers)
Glass Physics and Chemistry     Hybrid Journal   (1 follower)
Granular Matter     Hybrid Journal   (2 followers)
Graphs and Combinatorics     Hybrid Journal   (4 followers)
Handbook of Geophysical Exploration: Seismic Exploration     Full-text available via subscription  
Handbook of Metal Physics     Full-text available via subscription  
Handbook of Surface Science     Full-text available via subscription   (2 followers)
Handbook of Thermal Analysis and Calorimetry     Full-text available via subscription  
Handbook of Thermal Conductivity     Full-text available via subscription   (1 follower)
Haptics, IEEE Transactions on     Hybrid Journal   (4 followers)
Heat and Mass Transfer     Hybrid Journal   (11 followers)
Heat Transfer - Asian Research     Hybrid Journal   (5 followers)
High Energy Density Physics     Hybrid Journal   (1 follower)
High Pressure Research: An International Journal     Hybrid Journal   (1 follower)
High Temperature     Hybrid Journal  
Hyperfine Interactions     Hybrid Journal   (2 followers)
IEEE Electromagnetic Compatibility Magazine     Full-text available via subscription   (2 followers)
IEEE Journal of Quantum Electronics     Hybrid Journal   (12 followers)
IEEE Photonics Technology Letters     Hybrid Journal   (3 followers)
IEEE Signal Processing Magazine     Full-text available via subscription   (21 followers)
IEEE Transactions on Electromagnetic Capability     Hybrid Journal   (10 followers)
IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control     Hybrid Journal   (4 followers)
IET Optoelectronics     Hybrid Journal   (1 follower)
Il Colle di Galileo     Open Access  
Imaging Science Journal, The     Hybrid Journal   (2 followers)
Indian Journal of Biochemistry and Biophysics (IJBB)     Open Access   (4 followers)
Indian Journal of Physics     Hybrid Journal   (5 followers)
Indian Journal of Pure & Applied Physics (IJPAP)     Open Access   (8 followers)
Indian Journal of Radio & Space Physics (IJRSP)     Open Access   (4 followers)
Industrial Electronics, IEEE Transactions on     Hybrid Journal   (9 followers)
Industry Applications, IEEE Transactions on     Hybrid Journal   (5 followers)
Infinite Dimensional Analysis, Quantum Probability and Related Topics     Hybrid Journal  
InfraMatics     Open Access  
Infrared Physics & Technology     Hybrid Journal  
Intelligent Transportation Systems Magazine, IEEE     Full-text available via subscription   (1 follower)
Intermetallics     Hybrid Journal   (4 followers)
International Applied Mechanics     Hybrid Journal   (3 followers)
International Geophysics     Full-text available via subscription   (3 followers)
International Heat Treatment & Surface Engineering     Hybrid Journal   (2 followers)
International Journal for Computational Methods in Engineering Science and Mechanics     Hybrid Journal   (9 followers)
International Journal for Ion Mobility Spectrometry     Hybrid Journal   (1 follower)
International Journal for Simulation and Multidisciplinary Design Optimization     Full-text available via subscription   (1 follower)
International Journal of Abrasive Technology     Hybrid Journal   (2 followers)
International Journal of Aeroacoustics     Full-text available via subscription   (5 followers)
International Journal of Applied Electronics in Physics & Robotics     Open Access  
International Journal of Astronomy and Astrophysics     Open Access   (3 followers)
International Journal of Computational Fluid Dynamics     Hybrid Journal   (9 followers)
International Journal of Computational Materials Science and Surface Engineering     Hybrid Journal   (7 followers)
International Journal of Damage Mechanics     Hybrid Journal   (4 followers)
International Journal of Fatigue     Hybrid Journal   (5 followers)

  First | 1 2 3 4 5 6 7 | Last

Hyperfine Interactions    [4 followers]  Follow    
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 1572-9540 - ISSN (Online) 0304-3843
     Published by Springer-Verlag Homepage  [2187 journals]   [SJR: 0.266]   [H-I: 34]
  • Antimatter-gravity couplings, and Lorentz symmetry
    • Abstract: Abstract Implications of possible CPT and Lorentz violation for antimatter-gravity experiments as well as other antimatter tests are considered in the context of the general field-theory-based framework of the Standard-Model Extension (SME).
      PubDate: 2014-04-17
       
  • Gas-cell-based setup for the production and study of neutron rich heavy
           nuclei
    • Abstract: Abstract The present limits of the upper part of the nuclear map are very close to stability while the unexplored area of heavy neutron-rich nuclides along the neutron closed shell N = 126 is extremely important for nuclear astrophysics investigations and, in particular, for the understanding of the r-process of astrophysical nucleosynthesis. This area of the nuclear map can be reached neither in fusion–fission reactions nor in fragmentation processes widely used nowadays for the production of exotic nuclei. A new way was recently proposed for the production of these nuclei via low-energy multi-nucleon transfer reactions. The estimated yields of neutron-rich nuclei are found to be significantly high in such reactions and several tens of new nuclides can be produced, for example, in the near-barrier collision of 136Xe with 208Pb. A new setup is proposed to produce and study heavy neutron-rich nuclei located along the neutron closed shell N = 126.
      PubDate: 2014-04-17
       
  • RILIS applications at CERN/ISOLDE
    • Abstract: Abstract Since 2011 the ISOLDE Resonance Ionization Laser Ion Source (RILIS) has comprised a dual system of three dye and three Ti:sapphire lasers capable of gap-free wavelength tuning from 210 to 950 nm. Temporal synchronization of the lasers has enabled several operating modes to be established which make optimal use of the complementary characteristics of each laser type. This flexibility of the system has presented several opportunities for additional atomic spectroscopy studies and ionization scheme development, whilst also enabling an increase in the number of operating hours for standard ion beam production. The extended capabilities of the dual-RILIS system are exemplified by the recent operational highlights. These include on-line ionization scheme development (At, Ca), measurements of ionization energies (At, Po), in-source resonance ionization spectroscopy of exotic isotopes (At, Au, Po), and the provision of a fibre-coupled narrow-linewidth Ti:sapphire beam for the on-line commissioning of the CRIS experiment (Fr).
      PubDate: 2014-04-15
       
  • Structure and occurrences of ≪ green rust ≫ related new
           minerals of the ≪        class="a-plus-plus">fougérite ≫ group,
           trébeurdenite and
           mössbauerite,
           belonging to the ≪ hydrotalcite ≫ supergroup; how
           Mössbauer spectroscopy helps XRD.
    • Abstract: Abstract Mössbauer spectroscopy yields decisive information for interpreting x-ray diffraction (XRD) patterns in the case of ‘green rusts” with intercalated CO $_{3}^{2-}$ anions, i.e. the chemical analogs of the three minerals that constitute within the ≪ hydrotalcite ≫ supergroup comprising 44 minerals the “fougèrite” group where the structure stays globally unchanged. The only difference comes from the deprotonation of OH− ions at the apices of the octahedrons occupied by the Fe cations so that Fe I I ions become Fe I I I . Low angle x-ray diffraction using synchrotron radiation displays the presence of many polytypes which reflects the stacking of brucite like layers and anion interlayers so that a 2D long range order of anions stays unchanged from fougèrite to mössbauerite.
      PubDate: 2014-04-11
       
  • ELENA: the extra low energy anti-proton facility at CERN
    • Abstract: Abstract At the last LEAP conference in Vancouver 2011 the authors stated that a project ”ELENA”, as an abbreviation for Extra Low ENergy Antiproton ring and as first discussed in 1982 for LEAR by H. Herr et al., was freshly proposed with a substantial new design and revised layout and that it was under consideration to be built at CERN. ELENA is an upgrade of the Anti-proton Decelerator (AD) at CERN and is devoted to special experiments with physics using low energy anti-protons. The main topics are the anti-hydrogen production and consecutive studies of the features of this anti-matter atom as well as the anti-proton nucleon interaction by testing the QED to high precision. During the last years the project underwent several steps in presentations at different committees at CERN and was finally approved such that the construction has started. ELENA will increase the number of useful anti-protons by about two orders of magnitude and will allow to serve up to four experiments simultaneously. Very first and convincing results from the experiments at the AD have been published recently. For high precision physics, however, it appears to be cumbersome, time consuming and ineffective when collecting the needed large numbers and high densities of anti-proton clouds with the present AD. Both the effectiveness and the availability for additional experiments at this unique facility will drastically increase, when the anti-proton beam of presently 5 MeV kinetic energy is reduced by the additional decelerator ELENA to 100 keV.
      PubDate: 2014-04-10
       
  • Demonstration of the two-chamber approach for high-voltage measurements
           using collinear laser spectroscopy
    • Abstract: Abstract An electronic measurement of high-voltages of several ten kV with accuracy as required for precision experiments is currently only feasible using highly sophisticated voltage dividers. Collinear laser spectroscopy can provide a direct and precise measurement of high-voltages using the Doppler shift of accelerated ions. Although proposed already in 1982, a measurement with relative accuracy better than 10−4 was not reported so far. To improve this accuracy, a dedicated new setup for high-voltage measurements will be installed at the Technische Universität Darmstadt. A two-chamber approach will be used to remove uncertainties due to the insufficiently known starting potential inside the ion source. Here we present a demonstration of the pump-and-probe technique performed in preparatory studies at the TRIGA-LASER experiment in Mainz.
      PubDate: 2014-04-09
       
  • Theory overview of testing fundamental symmetries
    • Abstract: Abstract I review first some theoretical motivations for violation of Lorentz and/or CPT Invariance. Although the latter symmetries may be violated in a quantum gravity setting, nevertheless there are situations in which these violations are due to a given classical background geometry that may characterised early epochs of our Universe, and in fact be responsible for the observed dominance of matter over antimatter in the Universe. In this way I estimate some of the coefficients of the Standard Model Extension (SME), which is a framework for a field theoretic study of such a breakdown of fundamental symmetries. Then I describe briefly some tests of these symmetries, giving emphasis in low-energy antiproton physics and electric dipole moment measurements, of interest to this conference. I also mention the rôle of entangled states of neutral mesons in providing independent measurements of T(ime reversal) and CP Violation, thus providing independent tests of CPT symmetry, as well as novel (“smoking-gun” type) tests of decoherence-induced CPT violation, which may characterise some models of quantum gravity.
      PubDate: 2014-04-08
       
  • Coherent meson production in antinucleon annihilation on nuclei
    • Abstract: Abstract A phenomenological optical potential for antinucleon-nucleon (N̅N) interaction in an energy range of 1 to 15 GeV is presented in an eikonal model. In addition to the discussion of the strength and energy dependence, the potential is used to describe initial state interactions for coherent meson production on nuclei. To describe nuclear matter effects, Hartree-Fock Bogoliobuv (HFB) densities are used. As a first step we calculate the production of two mesons, namely pions. To cover the large energy range, the final state pion-nucleus ( π A) interaction is improved by adding resonances beyond the Δ resonance to a Kisslinger-type ansatz. Results for N̅N and π A cross sections are presented.
      PubDate: 2014-04-03
       
  • Beam life time studies and design optimization of the Ultra-low energy
           Storage Ring
    • Abstract: Abstract The Ultra-low energy electrostatic Storage Ring (USR) at the future Facility for Low-energy Antiproton and Ion Research (FLAIR) will provide cooled beams of antiprotons in the energy range between 300 keV down to 20 keV. Based on the original design concept developed in 2005, the USR has been completely redesigned over the past few years by the QUASAR Group. The ring structure is now based on a ’split achromat’ lattice. This ensures compact ring dimensions of 10 m × 10 m, whilst allowing both, in-ring experiments with gas jet targets and studies with extracted beams. In the USR, a wide range of beam parameters shall be provided, ranging from very short pulses in the nanosecond regime to a coasting beam. In addition, a combined fast and slow extraction scheme will be featured that allows for providing external experiments with cooled beams of different time structure. Detailed investigations into the dynamics of low energy beams, including studies into the long term beam dynamics and ion kinetics, beam life time, equilibrium momentum spread and equilibrium lateral spread during collisions with an internal target were carried out. This required the development of new simulation tools to further the understanding of beam storage with electrostatic fields. In addition, studies into beam diagnostics methods for the monitoring of ultra-low energy ions at beam intensities less than 10 6 were carried out. This includes instrumentation for the early commissioning of the machine, as well as for later operation with antiprotons. In this paper, on overview of the technical design of the USR is given with emphasis on two of the most important operating modes, long term beam dynamics and the design of the beam diagnostics system.
      PubDate: 2014-04-02
       
  • Beam preparation for studying the gravitational behavior of antimatter at
           rest (GBAR)
    • Abstract: Abstract The specific antiproton- and positron-beam requirements of the CERN AD-7 experiment, GBAR (Gravitational Behavior of Antimatter at Rest) are presented. GBAR will synthesize antihydrogen ions which will be sympathetically cooled before performing a free-fall experiment on the atom. Antiprotons delivered by CERN’s ELENA facility in 100-keV, 300-ns pulses will be electrostatically decelerated and transformed to keV energies using a pulsed drift tube. Positrons are created using a linear electron accelerator and collected into a Penning-Malmberg trap. Descriptions of these ion optical systems are given along with the status.
      PubDate: 2014-03-28
       
  • The P̅ANDA apparatus
    • Abstract: Abstract The P̅ANDA experiment will make use of cooled antiproton beams of unprecedented quality that will be available at the Facility for Antiproton and Ion Research (FAIR) in Darmstadt. The envisaged physics program includes: meson spectroscopy, baryon antibaryon production, baryon spectroscopy, hypernuclar physics, hadron properties in the nuclear medium and electromagnetic processes. This rich physics program asks for a general purpose apparatus. The design of the experiment is an advanced stage and the R&D phase is approaching its final phase, as resulted by most of the Technical Design Reports (TDRs) being already completed or under writing. In addition the production phase has already started for the electromagnetic calorimeter.
      PubDate: 2014-03-25
       
  • Mössbauer spectroscopy of europium-containing glasses: optical
           activator study for x-ray image plates
    • Abstract: Abstract A fluorozirconate glass (ZBLAN) containing BaCl 2 nanocrystals doped with divalent Eu is a promising material for x-ray image plates for medical diagnosis. Since it is known that Eu 2+ readily oxidizes to Eu 3+, which reduces fluorescence efficiency of the image plates, 151Eu Mössbauer spectroscopy was used in this work to monitor the Eu oxidation state of the samples during degradation over time in the presence of ambient humidity. In addition, Mössbauer spectroscopic experiments show that the oxidation state has already changed during the glass melt: The sample made from 5 mol% EuCl 2 contained 78 % EuCl 2 + 22 % EuCl 3 deduced from the relative areas of the absorption lines. The sample made from 2.5 mol% EuCl2 + 2.5 mol% EuCl2 contained 37 % EuCl2 + 63 % EuCl3, i.e. 26 % of the original EuCl 2 was oxidized to EuCl 3.
      PubDate: 2014-03-25
       
  • A pellet tracking system for the PANDA experiment
    • Abstract: Abstract Frozen microspheres of hydrogen (pellets) will be one of the target types for the future hadron physics experiment PANDA at FAIR (GSI, Darmstadt, Germany) [1]. Pellets with a diameter of 25– μm are generated about 3 meters above the interaction region, to which they travel with a velocity around 80 m/s inside a narrow pipe. The interaction region is defined by the overlap of the pellet stream and the accelerator beam and has a size of a few millimeters. One would like to know the interaction point more precisely, to have better possibilities to reconstruct particle tracks and events e.g. in charmonium decay studies. One would also like to suppress background events that do not originate in a pellet, but e.g. may occur in rest gas, that is present in the beam pipe. A solution is provided by the presented pellet tracking system together with a target operation mode that provides one and only one pellet in the interaction region most of the time. The goal is to track individual pellets in order to know their position with a resolution of a few tenths of a millimeter at the time of an interaction. The system must also be highly efficient and provide tracking information for essentially all pellets that pass the interaction region. Presented results from the design studies show that the goals can be fulfilled by this solution.
      PubDate: 2014-03-20
       
  • Perspectives for low energy antiproton physics at FAIR
    • Abstract: Abstract The CRYRING accelerator, previously located at the Manne Siegbahn Laboratory of Stockholm University, has been chosen by the FLAIR collaboration as the central accelerator for the planned facility. It has been modified to allow for high-energy injection and extraction and is capable of providing fast and slow extracted beams of antiprotons and highly charged ions. It is currently being installed at the ESR of GSI Darmstadt where it can be used with highly charged ions. The future possibilities for its use with slow antiprotons will be discussed.
      PubDate: 2014-03-20
       
  • SPARC collaboration: new strategy for storage ring physics at FAIR
    • Abstract: Abstract SPARC collaboration at FAIR pursues the worldwide unique research program by utilizing storage ring and trapping facilities for highly-charged heavy ions. The main focus is laid on the exploration of the physics at strong, ultra-short electromagnetic fields including the fundamental interactions between electrons and heavy nuclei as well as on the experiments at the border between nuclear and atomic physics. Very recently SPARC worked out a realization scheme for experiments with highly-charged heavy-ions at relativistic energies in the High-Energy Storage Ring HESR and at very low-energies at the CRYRING coupled to the present ESR. Both facilities provide unprecedented physics opportunities already at the very early stage of FAIR operation. The installation of CRYRING, dedicated Low-energy Storage Ring (LSR) for FLAIR, may even enable a much earlier realisation of the physics program of FLAIR with slow anti-protons.
      PubDate: 2014-03-20
       
  • Using Mössbauer spectroscopy to choose the sites that can be occupied
           by divalent tin
    • Abstract: Abstract Mössbauer spectroscopy can be a useful structural tool to assist crystallographic methods for site assignment when the compound under investigation contains divalent tin. The goal of this work was to show that the structure of tin(II) fluoride, also know as stannous fluoride, SnF2, could have been solved 14 years earlier if Mössbauer spectroscopic results, already known, had been used. A first attempt to solve the crystal structure, carried out by Bergerhoff in 1962 seemed to find the tin positions, however, it failed to find the positions of fluorine. Further extensive studies by Dénès et al. in the mid 1970s yielded the same results as those of Bergerhoff, despite the use of a Nonius CAD-4 automatic diffractometer, in contrast with Bergerhoff’s film work. The tin positions yielded a residual of 0.23, and Fourier difference maps showed significant electron density that could be fluorine atoms, however, their number did not match the number of fluorine atoms expected and several F-F distances were way too short. In addition, refinement using these possible fluorine positions led to no improvement of the residual factor. Finally, the crystal structure was published by McDonald et al. in 1976. It was found that the tin sublattice determined by Bergerhoff was basically correct, except that half of the tin atoms found by Bergerhoff to be on the (4b) and (4e) special Wyckoff sites were actually on the (8f) general site. A translation of the origin of the unit-cell by the [1/8, 0, 3/16] vector allows to change the tin Wyckoff sites from (4b), (4e) and (8f) to two (8f) sites, while keeping the basic spatial distribution of tin. A method has now been designed, using 119Sn Mössbauer spectroscopy, to test the suitability of some Wyckoff sites for divalent tin, using the Mössbauer spectrum. The tin(II) doublet (δ = 3.430(3) mm/s, Δ = 1.532(3) mm/s) shows that the lone pair is on a hybrid orbital, therefore, it is stereoactive, and it results that tin cannot be on either the (4b) or (4e) tin site since both an inversion center and a 2-fold axis would generate a second lone pair unless the 2-fold axis were along the tin-lone pair axis.
      PubDate: 2014-03-15
       
  • Separation efficiency of the MASHA facility for short-lived mercury
           isotopes
    • Abstract: Abstract The mass-separator MASHA built to identify Super Heavy Elements by their mass-to-charge ratios is described. The results of the off- and on-line measurements of its separation efficiency are presented. In the former case four calibrated leaks of noble gases were used. In the latter the efficiency was measured via 284 MeV $^{40}$ Ar beam and with using the hot catcher. The ECR ion source was used in both cases. The $\alpha $ -radioactive isotopes of mercury produced in the complete fusion reaction $^{40}$ Ar+ $^{144}$ Sm $\rightarrow ^{184-xn}$ Hg+xn were detected at the mass-separator focal plane. The half-lives and the separation efficiency for the short-lived mercury isotopes were measured. Potentialities of the MEDIPIX detector system have been demonstrated for future use at the mass-separator MASHA.
      PubDate: 2014-03-11
       
  • The first barium tin(II) bromide fluoride
    • Abstract: Abstract In an effort to prepare barium tin(II) bromide fluorides for the first time, possibly similar to the chloride fluorides obtained earlier in our laboratory, precipitation reactions were carried out by mixing aqueous solutions of SnF2 and of BaBr2.2H2O. In contrast with the chloride fluoride system, a single powdered phase was obtained throughout the SnF2 – BaBr2 system, with the yield being maximum at X ≈ 0.25, where X is the molar fraction of barium bromide in the reaction mixture. Phase identification with the JCPDS database failed to produce a match, confirming that a new phase had been produced. The exact chemical composition of the new compound has not been obtained yet. Based on the X value for the maximum yield, the Sn/Ba ratio is likely to be 3/1 or 2/1. The Mössbauer spectrum at ambient conditions shows that bonding to tin(II) is covalent, therefore with the tin lone pair being stereoactive. The Mössbauer parameters (δ = 3.68 mm/s, Δ = 0.99 mm/s) are similar to those of SnBrF and of Sn2BrF5, thereby showing that tin is bonded to both fluorine and bromine. The larger isomer shift and lower quadrupole splitting than in tin(II) fluorides show that the stereoactivity of the tin lone pair is lower than in the fluorides. The Mössbauer parameters fit well the linear correlation of the quadrupole splitting versus the isomer shift” that has been shown to be present in other series of tin(II) compounds. The linear decrease on this correlation shows that the contribution of non-spherical orbitals (p and d) to the lone pair is a much larger contributor to the quadrupole splitting than lattice distortions. The structure is likely made of Ba2+ cations and tin(II) fluoride bromide polyatomic anions, with covalent bonding withinthe anions.
      PubDate: 2014-03-07
       
  • Preface
    • PubDate: 2014-03-05
       
  • Laser spectroscopy methods for probing highly charged ions at GSI
    • Abstract: Abstract We describe two opposite and partly complementary experimental approaches for performing high-precision laser spectroscopy of dipole-forbidden transitions in highly charged ions. We report on the wavelength determination of the ground state hyperfine transitions in hydrogen-like and lithium-like bismuth ions confined in the experimental storage ring at GSI. Direct comparison of the experimental results with theoretical predictions reveals an agreement of the specific hyperfine-structure splitting difference $\Delta ^{\prime }E$ within the 1- σ confidence interval of the experimental value. Additionally, we discuss an experimental strategy based on ion manipulation and cooling in a cylindrical open-endcap Penning trap to further increase the precision of the previous measurement. Trapping and laser cooling of external produced singly charged magnesium ions is demonstrated. This represents a first step towards sympathetic cooling of simultaneously confined ion species in order to perform laser spectroscopy measurements on highly charged ions nearly at rest. These measurements will offer new prospects in the field of laser-based tests of quantum electrodynamics in strong electric and magnetic fields.
      PubDate: 2014-03-05
       
 
 
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