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Sample records for heavy electron state

  1. Heavy-electron materials

    SciTech Connect

    Fisk, Z.; Ott, H.R.; Smith, J.L.

    1986-01-01

    De Haas-van Alphen results demonstrated the existence of a Fermi surface at sufficiently low temperature and show that the entire Fermi surface involves heavy electrons. The phase transitions in their heavy-electron state are discussed. These are either magnetic or superconducting. 38 refs., 6 figs., 2 tabs. (WRF)

  2. Studying dissociative electron attachment through formation of heavy-Rydberg ion-pair states

    NASA Astrophysics Data System (ADS)

    Kelley, Michael; Buathong, Sitti; Dunning, F. Barry

    2016-05-01

    Following dissociative electron transfer in collisions between Rydberg atoms and electron-attaching targets, it is possible for the resulting pair of ions to remain electrostatically bound, forming heavy-Rydberg ion-pair states. Precise measurement of the velocity distributions of such ion-pair states provides information concerning the dissociation dynamics of the excited intermediates initially created by electron transfer. Here, electric-field-induced dissociation is used to detect the product ion pairs and observe their velocity distributions. These distributions are analyzed with the aid of a Monte Carlo collision code that models the electron transfer. Measurements with a number of different target species show that through this analysis, dissociation energetics, the branching ratios into different dissociation products, and the lifetimes of the excited intermediates can be examined. Research supported by the Robert A. Welch Foundation.

  3. Electronic excitation of ground state atoms by collision with heavy gas particles

    NASA Technical Reports Server (NTRS)

    Hansen, C. Frederick

    1993-01-01

    Most of the important chemical reactions which occur in the very high temperature air produced around space vehicles as they enter the atmosphere were investigated both experimentally and theoretically, to some extent at least. One remaining reaction about which little is known, and which could be quite important at the extremely high temperatures that will be produced by the class of space vehicles now contemplated - such as the AOTV - is the excitation of bound electron states due to collisions between heavy gas particles. Rates of electronic excitation due to free electron collisions are known to be very rapid, but because these collisions quickly equilibrate the free and bound electron energy, the approach to full equilibrium with the heavy particle kinetic energy will depend primarily on the much slower process of bound electron excitation in heavy particle collisions and the subsequent rapid transfer to free electron energy. This may be the dominant mechanism leading to full equilibrium in the gas once the dissociation process has depleted the molecular states so the transfer between molecular vibrational energy and free electron energy is no longer available as a channel for equilibration of free electron and heavy particle kinetic energies. Two mechanisms seem probable in electronic excitation by heavy particle impact. One of these is the collision excitation and deexcitation of higher electronic states which are Rydberg like. A report, entitled 'Semi-Classical Theory of Electronic Excitation Rates', was submitted previously. This presented analytic expressions for the transition probabilities, assuming that the interaction potential is an exponential repulsion with a perturbation ripple due to the dipole-induced dipole effect in the case of neutral-neutral collisions, and to the ion-dipole interaction in the case of ion-neutral collisions. However the above may be, there is little doubt that excitation of ground state species by collision occurs at the

  4. Lifetimes of Heavy-Rydberg Ion-Pair States Formed through Rydberg Electron Transfer

    SciTech Connect

    Cannon, M.; Wang, C. H.; Dunning, F. B.; Reinhold, Carlos O

    2010-01-01

    The lifetimes of K{sup +}-Cl{sup -}, K{sup +}-CN{sup -}, and K{sup +}-SF{sub 6}{sup -} heavy-Rydberg ion-pair states produced through Rydberg electron transfer reactions are measured directly as a function of binding energy using electric field induced detachment and the ion-pair decay channels discussed. The data are interpreted using a Monte Carlo collision code that models the detailed kinematics of electron transfer reactions. The lifetimes of K{sup +}-Cl{sup -} ion-pair states are observed to be very long, >100 {micro}s, and independent of binding energy. The lifetimes of strongly bound (>30 meV) K{sup +}-CN{sup -} ion pairs are found to be similarly long but begin to decrease markedly as the binding energy is reduced below this value. This behavior is attributed to conversion of rotational energy in the CN{sup -} ion into translational energy of the ion pair. No long-lived K{sup +}-SF{sub 6}{sup -} ion pairs are observed, their lifetimes decreasing with increasing binding energy. This behavior suggests that ion-pair loss is associated with mutual neutralization as a result of charge transfer.

  5. Excited-state evolution probed by convoy-electron emission in relativistic heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Takabayashi, Y.; Ito, T.; Azuma, T.; Komaki, K.; Yamazaki, Y.; Tawara, H.; Takada, E.; Murakami, T.; Seliger, M.; Tökési, K.; O. Reinhold, C.; Burgdörfer, J.

    2003-10-01

    We present a joint experimental and theoretical study of convoy-electron emission resulting from highly-charged-ion transport through carbon foils at moderately relativistic speeds. Energy spectra of electrons ejected at 0° have been measured for 390 MeV/u hydrogen-like Ar17+ ions and 460 MeV/u (β=v/c=0.74,γ=1.49) Fe25+ (1s), Fe24+ (1s2), and Fe23+ (1s22s) incident on carbon foils with thicknesses from 25 to 8700 μg/cm2. Due to this unprecedented wide range of thicknesses, the sequential excitation and ionization of initially deeply bound electrons to highly excited states and continuum states can be followed in considerable detail. The analysis of the spectra is aided by simulations based on the classical transport theory which has been extended to relativistic energies and to multielectron projectiles. The motion of the projectile electron inside the solid target is calculated taking into account the Coulomb potential of the projectile ion and the multiple stochastic collisions with target cores and target electrons. Different phases of the convoy-electron emissions can be disentangled: direct ejection to the continuum, the transient buildup of an excited-state wave packet followed by ionization, and postionization modification of the continuum spectrum. We find good agreement between experiment and simulation for the evolution of charge states and the emission spectrum.

  6. Heavy metal phosphate nanophases in silica: influence of radiolysis probed via f-electron state properties

    SciTech Connect

    Beitz, James V. . E-mail: beitz@anl.gov; Williams, C.W.; Hong, K.-S.; Liu, G.K.

    2005-02-15

    We have assessed the feasibility of carrying out time- and wavelength-resolved laser-induced fluorescence measurements of radiation damage in glassy silica. The consequences of alpha decay of Es-253 in LaPO{sub 4} nanophases embedded in silica were probed based on excitation of 5f states of Cm{sup 3+}, Bk{sup 3+}, and Es{sup 3+} ions. The recorded emission spectra and luminescence decays showed that alpha decay of Es-253 ejected Bk-249 decay daughter ions into the surrounding silica and created radiation damage within the LaPO{sub 4} nanophases. This conclusion is consistent with predictions of an ion transport code commonly used to model ion implantation. Luminescence from the {sup 6}D{sub 7/2} state of Cm{sup 3+}was used as an internal standard. Ion-ion energy transfer dominated the dynamics of the observed emitting 5f states and strongly influenced the intensity of observed spectra. In appropriate sample materials, laser-induced fluorescence provides a powerful method for fundamental investigation of alpha-induced radiation damage in silica.

  7. Crossover Phase Diagram and Electronic State in the Heavy-Fermion Metamagnets UIr2Zn20 and UCo2Zn20

    NASA Astrophysics Data System (ADS)

    Hirose, Yusuke; Takeuchi, Tetsuya; Honda, Fuminori; Yoshiuchi, Shingo; Hagiwara, Masayuki; Yamamoto, Etsuji; Haga, Yoshinori; Settai, Rikio; Ōnuki, Yoshichika

    2015-07-01

    Crossover phase diagrams in the magnetic field versus temperature (H-T) plane of the nonmagnetic heavy-fermion metamagnets UT2Zn20 (T:Ir, Co) are studied by measuring the magnetic and electronic transport properties. The crossover phase diagrams of UIr2Zn20 and UCo2Zn20 are composed of a low-magnetic-field region (LFR) and a high-magnetic-field region (HFR), which are characterized by magnetic properties and the Hall effect, respectively. The LFR is found to form a closed area in the H-T plane, which is a quite different feature from the conventional uranium heavy-fermion compounds and the first observation in uranium compounds. From the drastic anomaly in the Hall effect at a metamagnetic field of UIr2Zn20, it is found that the metamagnetic behavior in UIr2Zn20 corresponds to a crossover from the heavy-fermion state to the field-induced ferromagnetic or polarized paramagnetic state accompanied by the reconstruction or topology change of Fermi surfaces. In UCo2Zn20, on the other hand, no sign of abrupt change in the electronic state at the metamagnetic field is observed. These contrastive crossover phase diagrams and the electronic state changes at the metamagnetic field are due to the different hybridization strengths between the 5f electrons of U atoms and the d electrons of Ir and Co atoms, leading to the differences in magnetic correlation and crystalline electric field ground state or the degree of itinerancy of 5f electrons.

  8. Large Fermi Surface of Heavy Electrons at the Border of Mott Insulating State in NiS2

    DOE PAGESBeta

    Friedemann, S.; Chang, H.; Gamża, M. B.; Reiss, P.; Chen, X.; Alireza, P.; Coniglio, W. A.; Graf, D.; Tozer, S.; Grosche, F. M.

    2016-05-12

    One early triumph of quantum physics is the explanation why some materials are metallic whereas others are insulating. While a treatment based on single electron states is correct for most materials this approach can fail spectacularly, when the electrostatic repulsion between electrons causes strong correlations. Not only can these favor new and subtle forms of matter, such as magnetism or superconductivity, they can even cause the electrons in a half-filled energy band to lock into position, producing a correlated, or Mott insulator. The transition into the Mott insulating state raises important fundamental questions. Foremost among these is the fate ofmore » the electronic Fermi surface and the associated charge carrier mass, as the Mott transition is approached. We report the first direct observation of the Fermi surface on the metallic side of a Mott insulating transition by high pressure quantum oscillatory measurements in NiS2. We find our results point at a large Fermi surface consistent with Luttinger's theorem and a strongly enhanced quasiparticle effective mass. These two findings are in line with central tenets of the Brinkman-Rice picture of the correlated metal near the Mott insulating state and rule out alternative scenarios in which the carrier concentration vanishes continuously at the metal-insulator transition.« less

  9. Large Fermi Surface of Heavy Electrons at the Border of Mott Insulating State in NiS2

    NASA Astrophysics Data System (ADS)

    Friedemann, S.; Chang, H.; Gamża, M. B.; Reiss, P.; Chen, X.; Alireza, P.; Coniglio, W. A.; Graf, D.; Tozer, S.; Grosche, F. M.

    2016-05-01

    One early triumph of quantum physics is the explanation why some materials are metallic whereas others are insulating. While a treatment based on single electron states is correct for most materials this approach can fail spectacularly, when the electrostatic repulsion between electrons causes strong correlations. Not only can these favor new and subtle forms of matter, such as magnetism or superconductivity, they can even cause the electrons in a half-filled energy band to lock into position, producing a correlated, or Mott insulator. The transition into the Mott insulating state raises important fundamental questions. Foremost among these is the fate of the electronic Fermi surface and the associated charge carrier mass, as the Mott transition is approached. We report the first direct observation of the Fermi surface on the metallic side of a Mott insulating transition by high pressure quantum oscillatory measurements in NiS2. Our results point at a large Fermi surface consistent with Luttinger’s theorem and a strongly enhanced quasiparticle effective mass. These two findings are in line with central tenets of the Brinkman-Rice picture of the correlated metal near the Mott insulating state and rule out alternative scenarios in which the carrier concentration vanishes continuously at the metal-insulator transition.

  10. Large Fermi Surface of Heavy Electrons at the Border of Mott Insulating State in NiS2

    PubMed Central

    Friedemann, S.; Chang, H.; Gamża, M. B.; Reiss, P.; Chen, X.; Alireza, P.; Coniglio, W. A.; Graf, D.; Tozer, S.; Grosche, F. M.

    2016-01-01

    One early triumph of quantum physics is the explanation why some materials are metallic whereas others are insulating. While a treatment based on single electron states is correct for most materials this approach can fail spectacularly, when the electrostatic repulsion between electrons causes strong correlations. Not only can these favor new and subtle forms of matter, such as magnetism or superconductivity, they can even cause the electrons in a half-filled energy band to lock into position, producing a correlated, or Mott insulator. The transition into the Mott insulating state raises important fundamental questions. Foremost among these is the fate of the electronic Fermi surface and the associated charge carrier mass, as the Mott transition is approached. We report the first direct observation of the Fermi surface on the metallic side of a Mott insulating transition by high pressure quantum oscillatory measurements in NiS2. Our results point at a large Fermi surface consistent with Luttinger’s theorem and a strongly enhanced quasiparticle effective mass. These two findings are in line with central tenets of the Brinkman-Rice picture of the correlated metal near the Mott insulating state and rule out alternative scenarios in which the carrier concentration vanishes continuously at the metal-insulator transition. PMID:27174799

  11. Large Fermi Surface of Heavy Electrons at the Border of Mott Insulating State in NiS2.

    PubMed

    Friedemann, S; Chang, H; Gamża, M B; Reiss, P; Chen, X; Alireza, P; Coniglio, W A; Graf, D; Tozer, S; Grosche, F M

    2016-01-01

    One early triumph of quantum physics is the explanation why some materials are metallic whereas others are insulating. While a treatment based on single electron states is correct for most materials this approach can fail spectacularly, when the electrostatic repulsion between electrons causes strong correlations. Not only can these favor new and subtle forms of matter, such as magnetism or superconductivity, they can even cause the electrons in a half-filled energy band to lock into position, producing a correlated, or Mott insulator. The transition into the Mott insulating state raises important fundamental questions. Foremost among these is the fate of the electronic Fermi surface and the associated charge carrier mass, as the Mott transition is approached. We report the first direct observation of the Fermi surface on the metallic side of a Mott insulating transition by high pressure quantum oscillatory measurements in NiS2. Our results point at a large Fermi surface consistent with Luttinger's theorem and a strongly enhanced quasiparticle effective mass. These two findings are in line with central tenets of the Brinkman-Rice picture of the correlated metal near the Mott insulating state and rule out alternative scenarios in which the carrier concentration vanishes continuously at the metal-insulator transition. PMID:27174799

  12. Experimental Search for a Heavy Electron

    DOE R&D Accomplishments Database

    Boley, C. D.; Elias, J. E.; Friedman, J. I.; Hartmann, G. C.; Kendall, H. W.; Kirk, P.N.; Sogard, M. R.; Van Speybroeck, L. P.; de Pagter, J. K.

    1967-09-01

    A search for a heavy electron of the type considered by Low and Blackmon has been made by studying the inelastic scattering of 5 BeV electrons from hydrogen. The search was made over a range of values of the mass of the heavy electron from 100 t0 1300 MeV. No evidence for such a particle was observed. Upper limits on the production cross sections were determined and employed to deducelimits on the values of the electron-photon-heavy electron coupling constant in Low and Blackmon=s theory.

  13. Multiple Electron Stripping of Heavy Ion Beams

    SciTech Connect

    D. Mueller; L. Grisham; I. Kaganovich; R. L. Watson; V. Horvat; K. E. Zaharakis; Y. Peng

    2002-06-25

    One approach being explored as a route to practical fusion energy uses heavy ion beams focused on an indirect drive target. Such beams will lose electrons while passing through background gas in the target chamber, and therefore it is necessary to assess the rate at which the charge state of the incident beam evolves on the way to the target. Accelerators designed primarily for nuclear physics or high energy physics experiments utilize ion sources that generate highly stripped ions in order to achieve high energies economically. As a result, accelerators capable of producing heavy ion beams of 10 to 40 Mev/amu with charge state 1 currently do not exist. Hence, the stripping cross-sections used to model the performance of heavy ion fusion driver beams have, up to now, been based upon theoretical calculations. We have investigated experimentally the stripping of 3.4 Mev/amu Kr 7+ and Xe +11 in N2; 10.2 MeV/amu Ar +6 in He, N2, Ar and Xe; 19 MeV/amu Ar +8 in He, N2, Ar and Xe; 30 MeV He 1 + in He, N2, Ar and Xe; and 38 MeV/amu N +6 in He, N2, Ar and Xe. The results of these measurements are compared with the theoretical calculations to assess their applicability over a wide range of parameters.

  14. Quantum critical behavior in heavy electron materials

    PubMed Central

    Yang, Yi-feng; Pines, David

    2014-01-01

    Quantum critical behavior in heavy electron materials is typically brought about by changes in pressure or magnetic field. In this paper, we develop a simple unified model for the combined influence of pressure and magnetic field on the effectiveness of the hybridization that plays a central role in the two-fluid description of heavy electron emergence. We show that it leads to quantum critical and delocalization lines that accord well with those measured for CeCoIn5, yields a quantitative explanation of the field and pressure-induced changes in antiferromagnetic ordering and quantum critical behavior measured for YbRh2Si2, and provides a valuable framework for describing the role of magnetic fields in bringing about quantum critical behavior in other heavy electron materials. PMID:24912172

  15. The Electronic Structure of Heavy Element Complexes

    SciTech Connect

    Bursten, Bruce E.

    2000-07-25

    The area of study is the bonding in heavy element complexes, and the application of more sophisticated electronic structure theories. Progress is recounted in several areas: (a) technological advances and current methodologies - Relativistic effects are extremely important in gaining an understanding of the electronic structure of compounds of the actinides, transactinides, and other heavy elements. Therefore, a major part of the continual benchmarking was the proper inclusion of the appropriate relativistic effects for the properties under study. (b) specific applications - These include organoactinide sandwich complexes, CO activation by actinide atoms, and theoretical studies of molecules of the transactinide elements. Finally, specific directions in proposed research are described.

  16. Theory of nuclear excitation by electron capture for heavy ions

    SciTech Connect

    Palffy, Adriana; Scheid, Werner; Harman, Zoltan

    2006-01-15

    We investigate the resonant process of nuclear excitation by electron capture (NEEC), in which a continuum electron is captured into a bound state of an ion with the simultaneous excitation of the nucleus. In order to derive the cross section a Feshbach projection operator formalism is introduced. Nuclear states and transitions are described by a nuclear collective model and making use of experimental data. Transition rates and total cross sections for NEEC followed by the radiative decay of the excited nucleus are calculated for various heavy-ion collision systems.

  17. Theory of exotic superconductivity and normal states of heavy electron and high temperature superconductivity materials. Progress report, February 15, 1994--February 14, 1995

    SciTech Connect

    Cox, D.L.

    1995-02-01

    This is a progress report for the DOE project covering the period 2/15/94 to 2/14/95. The PI had a fruitful sabbatical during this period, and had some important new results, particularly in the area of new phenomenology for heavy fermion superconductivity. Significant new research accomplishments are in the area of odd-in-time-reversal pairing states/staggered superconductivity, the two-channel Kondo lattice, and a general model for Ce impurities which admits one-, two-, and three-channel Kondo effects. Papers submitted touch on these areas: staggered superconductivity - a new phenomenology for UPt{sub 3}; theory of the two-channel Kondo lattice in infinite dimensions; general model of a Ce{sup 3+} impurity. Other work was done in the areas: Knight shift in heavy fermion alloys and compounds; symmetry analysis of singular pairing correlations for the two-channel Kondo impurity model.

  18. Heavy Electrons:. Electron Droplets Generated by Photogalvanic and Pyroelectric Effects

    NASA Astrophysics Data System (ADS)

    Krasnoholovets, Volodymyr; Kukhtarev, Nicolai; Kukhtareva, Tatiana

    Electron clusters, X-rays and nanosecond radio-frequency pulses are produced by 100 mW continuous-wave laser illuminating ferroelectric crystal of LiNbO3. A long-living stable electron droplet with the size of about 100μm has freely moved with the velocity ~0.5 cm/s in the air near the surface of the crystal experiencing the Earth gravitational field. The microscopic model of cluster stability, which is based on submicroscopic mechanics developed in the real physical space, is suggested. The role of a restraining force plays the inerton field, a substructure of the particles' matter waves, which a solitary one can elastically withstand the Coulomb repulsion of electrons. It is shown that electrons in the droplet are heavy electrons whose mass exceeds the rest mass of free electron at least 1 million of times. Application for X-ray imaging and lithography is discussed.

  19. Electronic energy states

    NASA Technical Reports Server (NTRS)

    1976-01-01

    One-electron wave functions are reviewed and approximate solutions of two-electron systems are given in terms of these one-electron functions. The symmetry effects associated with electron spin are reviewed and the effects of electron exchange on energy levels of the two-electron system are given. The coupling of electronic orbital and spin angular momentum is considered next and the Lande interval rule for Russell-Saunders or LS coupling is derived. The configurations possible for various multi-electron LS couplings are enumerated (examples from the first two rows of the periodic table are given), and the meaning of the spectroscopic nomenclature is discussed, particularly with respect to the degeneracies of the electron states involved. Next the nomenclature, symmetries, and degeneracies for electron states of diatomic molecules are discussed, and some examples for N2, O2, and NO are presented. The electronic partition functions and derivative thermodynamic properties are expressed in terms of these energies and degeneracies, and examples are given for some of the simple gas species encountered in the earth's atmosphere.

  20. Radiative transitions of heavy quarkonium states

    SciTech Connect

    De Fazio, Fulvia

    2009-03-01

    We study radiative decays of heavy QQ states, both for Q=c and Q=b, using an effective Lagrangian approach which exploits spin symmetry for such states. We use existing data on radiative quarkonium transitions to predict some unmeasured decay rates. We also discuss how these modes can be useful to understand the structure of X(3872)

  1. Metastable states of highly excited heavy ions

    NASA Technical Reports Server (NTRS)

    Pegg, D. J.; Griffin, P. M.; Sellin, I. A.; Smith, W. W.; Donnally, B.

    1973-01-01

    Description of the method used and results obtained in an experimental study of the metastable states of highly stripped heavy ions, aimed at determining the lifetimes of such states by the rates of autoionization and radiation. The significance and limitations of the results presented are discussed.

  2. Calculations of heavy ion charge state distributions for nonequilibrium conditions

    NASA Technical Reports Server (NTRS)

    Luhn, A.; Hovestadt, D.

    1985-01-01

    Numerical calculations of the charge state distributions of test ions in a hot plasma under nonequilibrium conditions are presented. The mean ionic charges of heavy ions for finite residence times in an instantaneously heated plasma and for a non-Maxwellian electron distribution function are derived. The results are compared with measurements of the charge states of solar energetic particles, and it is found that neither of the two simple cases considered can explain the observations.

  3. Heavy atom nitroxyl radicals. I: An ab initio study of the ground and lower electronic excited states of the H2As=O free radical

    NASA Astrophysics Data System (ADS)

    Tarroni, Riccardo; Clouthier, Dennis J.

    2009-09-01

    A series of ab initio calculations have been undertaken to predict the spectroscopic properties of the ground and first two excited states of the recently discovered arsenyl (H2AsO) free radical. This 13 valence electron species can be viewed as similar to the formaldehyde radical anion with a ground state electron configuration of ⋯(π)2(n)2(π∗)1. The arsenyl radical is nonplanar (pyramidal) in the ground state with a 59° out-of-plane angle and a 1.67 Å AsO bond length. It has a low-lying n-π ∗(Ã A2″) excited state (Te˜5000 cm-1) which has a much larger out-of-plane angle (86°) and longer AsO bond length (1.81 Å). The π-π ∗(B˜ A2') excited state at ˜20 500 cm-1 is less pyramidal (out-of-plane angle=70°) and has a somewhat shorter AsO bond (1.77 Å). Similar trends are found for the H2PO and H2NO free radicals, although the latter has a planar ground state, due to sp2 hybridization of the N atom, and a very long B˜ state AsO bond length. The geometric variations of the ground and excited states of the H2EO (E=N, P, As) radicals, as well as the ground states of the corresponding anions and cations, can be readily rationalized from the Walsh diagram of the anion. The variations in the E-O bond length are a result of changes in both the orbital occupancy and pyramidalization of the molecule. The results of the present work have been employed in the analysis of the B˜ A2'-X˜ A2' electronic band system of the H2AsO free radical as reported in the companion paper.

  4. Bound states of heavy flavor hyperons

    NASA Astrophysics Data System (ADS)

    Frömel, F.; Juliá-Díaz, B.; Riska, D. O.

    2005-04-01

    Several realistic phenomenological nucleon-nucleon interaction models are employed to investigate the possibility of bound deuteron-like states of such heavy flavor hyperons and nucleons, for which the interaction between the light flavor quark components is expected to be the most significant interaction. The results indicate that deuteron-like bound states are likely to form between nucleons and the Ξc' and Ξ charm hyperons as well as between Ξ hyperons and double-charm hyperons. Bound states between two Σ hyperons are also likely. In the case of beauty hyperons the corresponding states are likely to be deeply bound.

  5. Electron impact multiple ionization cross sections of heavy ions

    NASA Astrophysics Data System (ADS)

    Zeng, Jiaolong; Liu, Pengfei; Dai, Jiayu; Yuan, Jianmin

    2014-05-01

    Cross sections of electron impact ionization are important in modeling both astrophysical and laboratory plasmas. For heavy ions, accurate determination of this microscopic physical quantity is difficult due to the complex atomic structure. At high incident electron energy, inner-shell excitation and ionization processes can occur, which will result in complicated decay including Auger and radiative decay processes. For deep inner-shell excitation and ionization, cascaded Auger processes are very likely. Under conditions of collisional ionization equilibrium, the balance of electron-ion recombination and electron impact single ionization determines the charge state distribution (CSD). Accurate CSD, which in turn determined by accurate cross sections, is very important in a wide regime of spectroscopic diagnostics to infer the physical conditions of plasmas such as the electron temperature, electron density, and elemental abundance. As an illustrative example, the cross sections from the ground configuration of Sn13+ in forming Sn13+, -Sn16+ are reported in detail. The contributions from the electron impact excitation, electron impact ionization and resonant excitation processes are included.

  6. Quadrupolar Kondo effect in uranium heavy-electron materials?

    NASA Technical Reports Server (NTRS)

    Cox, D. L.

    1987-01-01

    The possibility of an electric quadrupole Kondo effect for a non-Kramers doublet on a uranium (U) ion is a cubic metallic host is demonstrated by model calculations showing a Kondo upturn in the resistivity, universal quenching of the quadrupolar moment, and a heavy-electron anomaly in the electronic specific heat. With inclusion of excited crystal-field levels, some of the unusual magnetic-response data in the heavy-electron superconductor UBe13 may be understood. Structural phase transitions at unprecedented low temperatures may occur in U-based heavy-electron materials.

  7. Two-fluid model for heavy electron physics

    NASA Astrophysics Data System (ADS)

    Yang, Yi-feng

    2016-07-01

    The two-fluid model is a phenomenological description of the gradual change of the itinerant and local characters of f-electrons with temperature and other tuning parameters and has been quite successful in explaining many unusual and puzzling experimental observations in heavy electron materials. We review some of these results and discuss possible implications of the two-fluid model in understanding the microscopic origin of heavy electron physics.

  8. Review of metastable states in heavy nuclei.

    PubMed

    Dracoulis, G D; Walker, P M; Kondev, F G

    2016-07-01

    The structure of nuclear isomeric states is reviewed in the context of their role in contemporary nuclear physics research. Emphasis is given to high-spin isomers in heavy nuclei, with [Formula: see text]. The possibility to exploit isomers to study some of the most exotic nuclei is a recurring theme. In spherical nuclei, the role of octupole collectivity is discussed in detail, while in deformed nuclei the limitations of the K quantum number are addressed. Isomer targets and isomer beams are considered, along with applications related to energy storage, astrophysics, medicine, and experimental advances. PMID:27243336

  9. Review of metastable states in heavy nuclei

    NASA Astrophysics Data System (ADS)

    Dracoulis, G. D.; Walker, P. M.; Kondev, F. G.

    2016-07-01

    The structure of nuclear isomeric states is reviewed in the context of their role in contemporary nuclear physics research. Emphasis is given to high-spin isomers in heavy nuclei, with A≳ 150 . The possibility to exploit isomers to study some of the most exotic nuclei is a recurring theme. In spherical nuclei, the role of octupole collectivity is discussed in detail, while in deformed nuclei the limitations of the K quantum number are addressed. Isomer targets and isomer beams are considered, along with applications related to energy storage, astrophysics, medicine, and experimental advances.

  10. Single electron states in polyethylene

    SciTech Connect

    Wang, Y.; MacKernan, D.; Cubero, D. E-mail: n.quirke@imperial.ac.uk; Coker, D. F.; Quirke, N. E-mail: n.quirke@imperial.ac.uk

    2014-04-21

    We report computer simulations of an excess electron in various structural motifs of polyethylene at room temperature, including lamellar and interfacial regions between amorphous and lamellae, as well as nanometre-sized voids. Electronic properties such as density of states, mobility edges, and mobilities are computed on the different phases using a block Lanczos algorithm. Our results suggest that the electronic density of states for a heterogeneous material can be approximated by summing the single phase density of states weighted by their corresponding volume fractions. Additionally, a quantitative connection between the localized states of the excess electron and the local atomic structure is presented.

  11. Single electron states in polyethylene

    NASA Astrophysics Data System (ADS)

    Wang, Y.; MacKernan, D.; Cubero, D.; Coker, D. F.; Quirke, N.

    2014-04-01

    We report computer simulations of an excess electron in various structural motifs of polyethylene at room temperature, including lamellar and interfacial regions between amorphous and lamellae, as well as nanometre-sized voids. Electronic properties such as density of states, mobility edges, and mobilities are computed on the different phases using a block Lanczos algorithm. Our results suggest that the electronic density of states for a heterogeneous material can be approximated by summing the single phase density of states weighted by their corresponding volume fractions. Additionally, a quantitative connection between the localized states of the excess electron and the local atomic structure is presented.

  12. Heavy Inertial Confinement Energy: Interactions Involoving Low charge State Heavy Ion Injection Beams

    SciTech Connect

    DuBois, Robert D

    2006-04-14

    During the contract period, absolute cross sections for projectile ionization, and in some cases for target ionization, were measured for energetic (MeV/u) low-charge-state heavy ions interacting with gases typically found in high and ultra-high vacuum environments. This information is of interest to high-energy-density research projects as inelastic interactions with background gases can lead to serious detrimental effects when intense ion beams are accelerated to high energies, transported and possibly confined in storage rings. Thus this research impacts research and design parameters associated with projects such as the Heavy Ion Fusion Project, the High Current and Integrated Beam Experiments in the USA and the accelerator upgrade at GSI-Darmstadt, Germany. Via collaborative studies performed at GSI-Darmstadt, at the University of East Carolina, and Texas A&M University, absolute cross sections were measured for a series of collision systems using MeV/u heavy ions possessing most, or nearly all, of their bound electrons, e.g., 1.4 MeV/u Ar{sup +}, Xe{sup 3+}, and U{sup 4,6,10+}. Interactions involving such low-charge-state heavy ions at such high energies had never been previously explored. Using these, and data taken from the literature, an empirical model was developed for extrapolation to much higher energies. In order to extend our measurements to much higher energies, the gas target at the Experimental Storage Ring in GSI-Darmstadt was used. Cross sections were measured between 20 and 50 MeV/u for U{sup 28+}- H{sub 2} and - N{sub 2}, the primary components found in high and ultra-high vacuum systems. Storage lifetime measurements, information inversely proportional to the cross section, were performed up to 180 MeV/u. The lifetime and cross section data test various theoretical approaches used to calculate cross sections for many-electron systems. Various high energy density research projects directly benefit by this information. As a result, the general

  13. Single electrons from heavy-flavor decays in collisions at.

    PubMed

    Adler, S S; Afanasiev, S; Aidala, C; Ajitanand, N N; Akiba, Y; Alexander, J; Amirikas, R; Aphecetche, L; Aronson, S H; Averbeck, R; Awes, T C; Azmoun, R; Babintsev, V; Baldisseri, A; Barish, K N; Barnes, P D; Bassalleck, B; Bathe, S; Batsouli, S; Baublis, V; Bazilevsky, A; Belikov, S; Berdnikov, Y; Bhagavatula, S; Boissevain, J G; Borel, H; Borenstein, S; Brooks, M L; Brown, D S; Bruner, N; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J M; Butsyk, S; Camard, X; Chai, J-S; Chand, P; Chang, W C; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choi, I J; Choi, J; Choudhury, R K; Chujo, T; Cianciolo, V; Cobigo, Y; Cole, B A; Constantin, P; d'Enterria, D; David, G; Delagrange, H; Denisov, A; Deshpande, A; Desmond, E J; Devismes, A; Dietzsch, O; Drapier, O; Drees, A; du Rietz, R; Durum, A; Dutta, D; Efremenko, Y V; El Chenawi, K; Enokizono, A; En'yo, H; Esumi, S; Ewell, L; Fields, D E; Fleuret, F; Fokin, S L; Fox, B D; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fung, S-Y; Garpman, S; Ghosh, T K; Glenn, A; Gogiberidze, G; Gonin, M; Gosset, J; Goto, Y; de Cassagnac, R Granier; Grau, N; Greene, S V; Perdekamp, M Grosse; Guryn, W; Gustafsson, H-A; Hachiya, T; Haggerty, J S; Hamagaki, H; Hansen, A G; Hartouni, E P; Harvey, M; Hayano, R; Hayashi, N; He, X; Heffner, M; Hemmick, T K; Heuser, J M; Hibino, M; Hill, J C; Holzmann, W; Homma, K; Hong, B; Hoover, A; Ichihara, T; Ikonnikov, V V; Imai, K; Isenhower, D; Ishihara, M; Issah, M; Isupov, A; Jacak, B V; Jang, W Y; Jeong, Y; Jia, J; Jinnouchi, O; Johnson, B M; Johnson, S C; Joo, K S; Jouan, D; Kametani, S; Kamihara, N; Kang, J H; Kapoor, S S; Katou, K; Kelly, S; Khachaturov, B; Khanzadeev, A; Kikuchi, J; Kim, D H; Kim, D J; Kim, D W; Kim, E; Kim, G-B; Kim, H J; Kistenev, E; Kiyomichi, A; Kiyoyama, K; Klein-Boesing, C; Kobayashi, H; Kochenda, L; Kochetkov, V; Koehler, D; Kohama, T; Kopytine, M; Kotchetkov, D; Kozlov, A; Kroon, P J; Kuberg, C H; Kurita, K; Kuroki, Y; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Ladygin, V; Lajoie, J G; Lebedev, A; Leckey, S; Lee, D M; Lee, S; Leitch, M J; Li, X H; Lim, H; Litvinenko, A; Liu, M X; Liu, Y; Maguire, C F; Makdisi, Y I; Malakhov, A; Manko, V I; Mao, Y; Martinez, G; Marx, M D; Masui, H; Matathias, F; Matsumoto, T; McGaughey, P L; Melnikov, E; Messer, F; Miake, Y; Milan, J; Miller, T E; Milov, A; Mioduszewski, S; Mischke, R E; Mishra, G C; Mitchell, J T; Mohanty, A K; Morrison, D P; Moss, J M; Mühlbacher, F; Mukhopadhyay, D; Muniruzzaman, M; Murata, J; Nagamiya, S; Nagle, J L; Nakamura, T; Nandi, B K; Nara, M; Newby, J; Nilsson, P; Nyanin, A S; Nystrand, J; O'Brien, E; Ogilvie, C A; Ohnishi, H; Ojha, I D; Okada, K; Ono, M; Onuchin, V; Oskarsson, A; Otterlund, I; Oyama, K; Ozawa, K; Pal, D; Palounek, A P T; Pantuev, V; Papavassiliou, V; Park, J; Parmar, A; Pate, S F; Peitzmann, T; Peng, J-C; Peresedov, V; Pinkenburg, C; Pisani, R P; Plasil, F; Purschke, M L; Purwar, A K; Rak, J; Ravinovich, I; Read, K F; Reuter, M; Reygers, K; Riabov, V; Riabov, Y; Roche, G; Romana, A; Rosati, M; Rosnet, P; Ryu, S S; Sadler, M E; Saito, N; Sakaguchi, T; Sakai, M; Sakai, S; Samsonov, V; Sanfratello, L; Santo, R; Sato, H D; Sato, S; Sawada, S; Schutz, Y; Semenov, V; Seto, R; Shaw, M R; Shea, T K; Shibata, T-A; Shigaki, K; Shiina, T; Silva, C L; Silvermyr, D; Sim, K S; Singh, C P; Singh, V; Sivertz, M; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Staley, F; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Sullivan, J P; Takagui, E M; Taketani, A; Tamai, M; Tanaka, K H; Tanaka, Y; Tanida, K; Tannenbaum, M J; Tarján, P; Tepe, J D; Thomas, T L; Tojo, J; Torii, H; Towell, R S; Tserruya, I; Tsuruoka, H; Tuli, S K; Tydesjö, H; Tyurin, N; van Hecke, H W; Velkovska, J; Velkovsky, M; Veszprémi, V; Villatte, L; Vinogradov, A A; Volkov, M A; Vznuzdaev, E; Wang, X R; Watanabe, Y; White, S N; Wohn, F K; Woody, C L; Xie, W; Yang, Y; Yanovich, A; Yokkaichi, S; Young, G R; Yushmanov, I E; Zajc, W A; Zhang, C; Zhou, S; Zhou, S J; Zolin, L

    2006-01-27

    The invariant differential cross section for inclusive electron production in p+p collisions at [FORMULA: SEE TEXT] has been measured by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider over the transverse momentum range 0.4electron spectrum from semileptonic decays of hadrons carrying heavy flavor, i.e., charm quarks or, at high , bottom quarks, is determined via three independent methods. The resulting electron spectrum from heavy-flavor decays is compared to recent leading and next-to-leading order perturbative QCD calculations. The total cross section of charm quark-antiquark pair production is determined to be [FORMULA: SEE TEXT]. PMID:16486684

  14. Heavy-ion induced electronic desorption of gas from metals

    SciTech Connect

    Molvik, A W; Kollmus, H; Mahner, E; Covo, M K; Bellachioma, M C; Bender, M; Bieniosek, F M; Hedlund, E; Kramer, A; Kwan, J; Malyshev, O B; Prost, L; Seidl, P A; Westenskow, G; Westerberg, L

    2006-12-19

    During heavy ion operation in several particle accelerators world-wide, dynamic pressure rises of orders of magnitude were triggered by lost beam ions that bombarded the vacuum chamber walls. This ion-induced molecular desorption, observed at CERN, GSI, and BNL, can seriously limit the ion beam lifetime and intensity of the accelerator. From dedicated test stand experiments we have discovered that heavy-ion induced gas desorption scales with the electronic energy loss (dE{sub e}/d/dx) of the ions slowing down in matter; but it varies only little with the ion impact angle, unlike electronic sputtering.

  15. Scaling in the Emergent Behavior of Heavy Electron Materials

    NASA Astrophysics Data System (ADS)

    Curro, N.; Young, B.-L.; Pines, D.; Schmalian, Joerg

    2004-03-01

    We show that the two fluid description of the Kondo lattice developed by Nakatsuji, Pines, and Fisk provides a quantitative explanation of the Knight shift anomaly that has been measured in a number of heavy electron materials. It enables us to identify the onset of the anomaly at a temperature, T, at which the heavy electron liquid emerges from a lattice of non-interacting Kondo centers, and to determine quantitatively the temperature evolution of the heavy electron spin susceptibility by combining measurements of the temperature dependence of the Knight shift with those of the bulk electronic spin susceptibility. We find that an excellent fit to existing experimental data in Ce, Yb and U based materials is obtained with a susceptibility whose temperature dependence follows the simple form: (1-T/T*)log T^*/T; a result that suggests that quite generally in Kondo lattices the emergent behavior of the heavy electron liquid can be characterized entirely by the single energy scale, T^*, that Nakatsuji et al. have proposed is a direct measure of the strength of nearest neighbor intersite magnetic coupling.

  16. ECR (electron cyclotron resonance) ion sources and applications with heavy-ion linacs

    SciTech Connect

    Pardo, R.C.

    1990-01-01

    The electron cyclotron resonance (ECR) ion source has been developed in the last few years into a reliable source of high charge-state heavy ions. The availability of heavy ions with relatively large charge-to-mass ratios (0.1--0.5) has made it possible to contemplate essentially new classes of heavy-ion linear accelerators. In this talk, I shall review the state-of-the-art in ECR source performance and describe some of the implications this performance level has for heavy-ion linear accelerator design. The present linear accelerator projects using ECR ion sources will be noted and the performance requirements of the ECR source for these projects will be reviewed. 30 refs., 3 figs.

  17. Heavy hadron-string states as weakly interacting heavy dark-matter particles

    NASA Astrophysics Data System (ADS)

    Kudryavtsev, V. A.

    2015-09-01

    Massive states (with energies ≥ 10 GeV) of a hadronic string (with a scale α' ≈ 1GeV-2) can have a very small coupling to ordinary baryons in the Universe. The lifetime of such states is of the order of or even greater than the age of the Universe. These heavy states are assumed to be possible candidates for the role of weakly interacting heavy dark-matter particles.

  18. The electronic structure of heavy fermions: Narrow temperature independent bands

    SciTech Connect

    Arko, A.J.; Joyce, J.J.; Smith, J.L.; Andrews, A.B.

    1996-08-01

    The electronic structure of both Ce and U heavy fermions appears to consist of extremely narrow temperature independent bands. There is no evidence from photoemission for a collective phenomenon normally referred to as the Kondo resonance. In uranium compounds a small dispersion of the bands is easily measurable.

  19. Bound-free electron-positron pair production in relativistic heavy-ion collisions

    SciTech Connect

    Senguel, M. Y.; Gueclue, M. C.; Fritzsche, S.

    2009-10-15

    The bound-free electron-positron pair production is considered for relativistic heavy ion collisions. In particular, cross sections are calculated for the pair production with the simultaneous capture of the electron into the 1s ground state of one of the ions and for energies that are relevant for the relativistic heavy ion collider and the large hadron colliders. In the framework of perturbation theory, we applied Monte Carlo integration techniques to compute the lowest-order Feynman diagrams amplitudes by using Darwin wave functions for the bound states of the electrons and Sommerfeld-Maue wave functions for the continuum states of the positrons. Calculations were performed especially for the collision of Au+Au at 100 GeV/nucleon and Pb+Pb at 3400 GeV/nucleon.

  20. Search for a heavy gauge boson $W$ ' in the final state with an electron and large missing transverse energy in $pp$ collisions at $\\sqrt{s}=7$ TeV

    SciTech Connect

    Khachatryan, Vardan; et al.

    2011-03-01

    A search for a heavy gauge boson W' has been conducted by the CMS experiment at the LHC in the decay channel with an electron and large transverse energy imbalance, using proton-proton collision data corresponding to an integrated luminosity of 36 inverse picobarns. No excess above standard model expectations is seen in the transverse mass distribution of the electron-(missing E_T) system. Assuming standard-model-like couplings and decay branching fractions, a W' boson with a mass less than 1.36 TeV/c^2 is excluded at 95% confidence level.

  1. Electron-Cloud Effects on Heavy-Ion Beams

    SciTech Connect

    Azevedo, T; Friedman, A; Cohen, R; Vay, J

    2004-03-29

    Stray electrons can be introduced in positive-charge accelerators for heavy ion fusion (or other applications) as a result of ionization of ambient gas or gas released from walls due to halo-ion impact, or as a result of secondary-electron emission. We are developing a capability for self-consistent simulation of ion beams with the electron clouds they produce. We report on an ingredient in this capability, the effect of specified electron cloud distributions on the dynamics of a coasting ion beam. We consider here electron distributions with axially varying density, centroid location, or radial shape, and examine both random and sinusoidally varying perturbations. We find that amplitude variations are most effective in spoiling ion beam quality, though for sinusoidal variations which match the natural ion beam centroid oscillation or breathing mode frequencies, the centroid and shape perturbations can also be effective. We identify a possible instability associated with resonance with the beam-envelope ''breathing'' mode. One conclusion from this study is that heavy-ion beams are surprisingly robust to electron clouds, compared to a priori expectations.

  2. Interchain electron states in polyethylene

    NASA Astrophysics Data System (ADS)

    Serra, S.; Tosatti, E.; Iarlori, S.; Scandolo, S.; Santoro, G.

    2000-08-01

    We present a theoretical study of the nature of the lowest empty conduction-band states in crystalline polyethylene (PE), conducted through density-functional electronic structure calculations. Results reveal that the wave function of the conduction-band edge is of interchain character, as opposed to the intrachain character of all the filled valence-band states. Thus, while a hole added to neutral PE will mainly belong to the PE chain backbone bonds, an added electron in PE will mostly reside between the chains, and far from the existing bonds. Moreover, the added electron state charge centroid is predicted to move further out from the chain backbone towards the low-density interstitial region, if and when the chains are pried apart. This suggests that injected electrons will naturally flow to low-density regions inside real PE, and that the experimentally established propensity of PE to expel electrons out of the bulk, should be directly related to the interchain nature of the conduction states.

  3. Experimental study of electron ejection by heavy ion irradiation of solids: Observation of forward and backward emitted electron jets

    NASA Astrophysics Data System (ADS)

    Zäpfel, T.; Hagmann, S.; Rothard, H.; Ullrich, J.; Kraft, G.; Schmidt-Böcking, H.; Groeneveld, K. O.

    2002-06-01

    Doubly differential cross sections for electron emission induced by the passage of swift heavy ions such as F q+ (1.5-2.0 MeV/u) through thin solid foil targets were measured at the Tandem accelerator of the JR Macdonald Laboratory at Kansas State University. The complete angular distribution of electron emission up to 4000 eV (beyond the maximum of the "binary encounter" electron peak) was determined as a function of the projectile charge state ( q=5 and 9) and the target material in a wide Z range: C ( Z=6), Al ( Z=13) and Au ( Z=79). Electrons emitted from the foils between 0 and ±180° with respect to the beam axis were energy and angle analysed by means of a toroidal electrostatic electron spectrometer equipped with a 2D position sensitive channelplate detector. In addition to low energy cascade electrons, electrons from collective excitation (plasmons), target Auger electrons, convoy electrons and binary encounter electrons, we also observe a new feature never before seen in electron angular distributions: narrow electron jets ("spikes") emitted along the ion beam axis in forward and backward directions. This observation is made possible by the good angular resolution of our spectrometer and the possibility to record the entire angular distribution in a single run.

  4. Simulating Electron Cloud Effects in Heavy-Ion Beams

    SciTech Connect

    Cohen, R.H.; Friedman, A.; Lund, S.W.; Molvik, A.W.; Azevedo, T.; Vay, J.-L.; Stoltz, P.; Veitzer, S.

    2004-08-04

    Stray electrons can be introduced in heavy ion fusion accelerators as a result of ionization of ambient gas or gas released from walls due to halo-ion impact, or as a result of secondary-electron emission. We summarize here results from several studies of electron-cloud accumulation and effects: (1) Calculation of the electron cloud produced by electron desorption from computed beam ion loss; the importance of ion scattering is shown; (2) Simulation of the effect of specified electron cloud distributions on ion beam dynamics. We find electron cloud variations that are resonant with the breathing mode of the beam have the biggest impact on the beam (larger than other resonant and random variations), and that the ion beam is surprisingly robust, with an electron density several percent of the beam density required to produce significant beam degradation in a 200-quadrupole system. We identify a possible instability associated with desorption and resonance with the breathing mode. (3) Preliminary investigations of a long-timestep algorithm for electron dynamics in arbitrary magnetic fields.

  5. Exotic heavy-quark states at Belle

    NASA Astrophysics Data System (ADS)

    Wang, Xiaolong; Belle Collaboration

    2016-03-01

    The search for multi-quark states beyond the meson (quark-antiquark) and baryon (three-quark) has resulted in the discovery of many new exotic states of matter, starting with the X(3872) discovery by Belle in 2003. We report selected recent results on searches for such states at Belle. supported by the Department of Energy Office of Science.

  6. HIGH-INTENSITY, HIGH CHARGE-STATE HEAVY ION SOURCES

    SciTech Connect

    ALESSI,J.G.

    2004-08-16

    There are many accelerator applications for high intensity heavy ion sources, with recent needs including dc beams for RIA, and pulsed beams for injection into synchrotrons such as RHIC and LHC. The present status of sources producing high currents of high charge state heavy ions is reviewed. These sources include ECR, EBIS, and Laser ion sources. Benefits and limitations for these type sources are described. Possible future improvements in these sources are also mentioned.

  7. Simulating Electron Clouds in Heavy-Ion Accelerators

    SciTech Connect

    Cohen, R.H.; Friedman, A.; Kireeff Covo, M.; Lund, S.M.; Molvik,A.W.; Bieniosek, F.M.; Seidl, P.A.; Vay, J-L.; Stoltz, P.; Veitzer, S.

    2005-04-07

    Contaminating clouds of electrons are a concern for most accelerators of positive-charged particles, but there are some unique aspects of heavy-ion accelerators for fusion and high-energy density physics which make modeling such clouds especially challenging. In particular, self-consistent electron and ion simulation is required, including a particle advance scheme which can follow electrons in regions where electrons are strongly-, weakly-, and un-magnetized. They describe their approach to such self-consistency, and in particular a scheme for interpolating between full-orbit (Boris) and drift-kinetic particle pushes that enables electron time steps long compared to the typical gyro period in the magnets. They present tests and applications: simulation of electron clouds produced by three different kinds of sources indicates the sensitivity of the cloud shape to the nature of the source; first-of-a-kind self-consistent simulation of electron-cloud experiments on the High-Current Experiment (HCX) at Lawrence Berkeley National Laboratory, in which the machine can be flooded with electrons released by impact of the ion beam and an end plate, demonstrate the ability to reproduce key features of the ion-beam phase space; and simulation of a two-stream instability of thin beams in a magnetic field demonstrates the ability of the large-timestep mover to accurately calculate the instability.

  8. Magnetism and superconductivity in heavy-electron metals

    SciTech Connect

    Ott, H.R.

    1994-12-31

    All the data and features of properties of heavy-electron systems mentioned in this presentation represent only a fraction of recent results obtained in this field. Nevertheless they should demonstrate that interesting physics may be explored in studies of these materials. Most results that are obtained are important with regard to the understanding of metals in general. These substances are suited for studies of all aspects of many-body effects among conduction electrons in metals and are an important link to quantum fluids or solids like {sup 3}He. The quite well established occurrence of unconventional superconductivity is among the most prominent features of heavy-electron physics and, also here, provides a merging of interest with another hot topic of condensed-matter physics, the phenomenon of superconductivity in oxides at relatively high temperatures and in organic substances. As a final comment the author recalls the importance of the materials-science aspects in these problems. The demonstrated strong influence of small amounts of impurities or imperfections on the physical properties of these substances certainly deserves further attention in future experimental and theoretical work.

  9. The STAR Heavy Flavor Tracker PXL detector readout electronics

    NASA Astrophysics Data System (ADS)

    Schambach, J.; Contin, G.; Greiner, L.; Stezelberger, T.; Sun, X.; Szelezniak, M.; Vu, C.

    2016-01-01

    The Heavy Flavor Tracker (HFT) is a recently installed micro-vertex detector upgrade to the STAR experiment at RHIC, consisting of three subsystems with various technologies of silicon sensors arranged in 4 concentric cylinders. The two innermost layers of the HFT close to the beam pipe, the Pixel ("PXL") subsystem, employ CMOS Monolithic Active Pixel Sensor (MAPS) technology that integrate the sensor, front-end electronics, and zero-suppression circuitry in one silicon die. This paper presents selected characteristics of the PXL detector part of the HFT and the hardware, firmware and software associated with the readout system for this detector.

  10. Spatial interferences in the electron transport of heavy-fermion materials

    NASA Astrophysics Data System (ADS)

    Zhang, Shu-feng; Liu, Yu; Song, Hai-Feng; Yang, Yi-feng

    2016-08-01

    The scanning tunneling microscopy/spectroscopy and the point contact spectroscopy represent major progress in recent heavy-fermion research. Both have revealed important information on the composite nature of the emergent heavy-electron quasiparticles. However, a detailed and thorough microscopic understanding of the similarities and differences in the underlying physical processes of these techniques is still lacking. Here we study the electron transport in the normal state of the periodic Anderson lattice by using the Keldysh nonequilibrium Green's function technique. In addition to the well-known Fano interference between the conduction and f -electron channels, our results further reveal the effect of spatial interference between different spatial paths at the interface on the differential conductance and their interesting interplay with the band features such as the hybridization gap and the Van Hove singularity. We find that the spatial interference leads to a weighted average in the momentum space for the electron transport and could cause suppression of the electronic band features under certain circumstances. In particular, it reduces the capability of probing the f -electron spectral weight near the edges of the hybridization gap for large interface depending on the Fermi surface of the lead. Our results indicate an intrinsic inefficiency of the point contact spectroscopy in probing the f electrons.

  11. From the Cover: PNAS Plus: Long range order and two-fluid behavior in heavy electron materials

    NASA Astrophysics Data System (ADS)

    Shirer, Kent R.; Shockley, Abigail C.; Dioguardi, Adam P.; Crocker, John; Lin, Ching H.; apRoberts-Warren, Nicholas; Nisson, David M.; Klavins, Peter; Cooley, Jason C.; Yang, Yi-feng; Curro, Nicholas J.

    2012-11-01

    The heavy electron Kondo liquid is an emergent state of condensed matter that displays universal behavior independent of material details. Properties of the heavy electron liquid are best probed by NMR Knight shift measurements, which provide a direct measure of the behavior of the heavy electron liquid that emerges below the Kondo lattice coherence temperature as the lattice of local moments hybridizes with the background conduction electrons. Because the transfer of spectral weight between the localized and itinerant electronic degrees of freedom is gradual, the Kondo liquid typically coexists with the local moment component until the material orders at low temperatures. The two-fluid formula captures this behavior in a broad range of materials in the paramagnetic state. In order to investigate two-fluid behavior and the onset and physical origin of different long range ordered ground states in heavy electron materials, we have extended Knight shift measurements to URu2Si2, CeIrIn5, and CeRhIn5. In CeRhIn5 we find that the antiferromagnetic order is preceded by a relocalization of the Kondo liquid, providing independent evidence for a local moment origin of antiferromagnetism. In URu2Si2 the hidden order is shown to emerge directly from the Kondo liquid and so is not associated with local moment physics. Our results imply that the nature of the ground state is strongly coupled with the hybridization in the Kondo lattice in agreement with phase diagram proposed by Yang and Pines.

  12. Many-Electron Properties of Heavy Rare Earth Films

    NASA Astrophysics Data System (ADS)

    Dottl, Lane Evan

    1992-01-01

    The electronic properties of gadolinium, terbium and dysprosium overlayers on several substrates, including Cu(100), Ni(111), Si(111) and W(110), have been studied with angle resolved photoemission using synchrotron radiation. A feature is observed at approximately 6 eV binding energy. It is proposed that the ~6 eV feature is a many-electron shake up satellite of localized 5d states. The proposed model requires that the photoemission site producing the satellite have more than one d-electron. Because the ground state electronic configuration of Gd, Tb and Dy crystals has one 5d-electron per unit cell, the strength of the satellite is sensitive to local and global changes in the 5d-band occupancy. The model compares favorably with results from a variety of experimental systems. It is found that the satellite is sensitive to surface contamination and film defects as well as interfacial alloying and chemical bonding.

  13. United States commitment to heavy lift launch vehicles

    NASA Technical Reports Server (NTRS)

    Gabris, Edward A.

    1991-01-01

    Progress made to date on a United States commitment to the development of heavy launch vehicles is reviewed. The involvement of the Executive Branch operating through the National Space Council, the Legislative Branch, the DOD, and NASA are addressed. The evolution of launch system requirements and the form, content, and rationale for the various decisions that have been made to date are discussed.

  14. A transverse electron target for heavy ion storage rings

    SciTech Connect

    Geyer, Sabrina Meusel, Oliver; Kester, Oliver

    2015-01-09

    Electron-ion interaction processes are of fundamental interest for several research fields like atomic and astrophysics as well as plasma applications. To address this topic, a transverse electron target based on the crossed beam technique was designed and constructed for the application in storage rings. Using a sheet beam of free electrons in crossed beam geometry promises a good energy resolution and gives access to the interaction region for spectroscopy. The produced electron beam has a length of 10 cm in ion beam direction and a width in the transverse plane of 5 mm. Therewith, electron densities of up to 10{sup 9} electrons/cm{sup 3} are reachable in the interaction region. The target allows the adjustment of the electron beam current and energy in the region of several 10 eV to a few keV. Simulations have been performed regarding the energy resolution for electron-ion collisions and its influence on spectroscopic measurements. Also, the effect on ion-beam optics due to the space charge of the electron beam was investigated. Presently the electron target is integrated into a test bench to evaluate its performance for its dedicated installation at the storage rings of the FAIR facility. Therefore, optical diagnostics of the interaction region and charge state analysis with a magnetic spectrometer is used. Subsequently, the target will be installed temporarily at the Frankfurt Low-Energy Storage Ring (FLSR) for further test measurements.

  15. Electron correlations in solid state physics

    SciTech Connect

    Freericks, J.K.

    1991-04-01

    Exactly solvable models of electron correlations in solid state physics are presented. These models include the spinless Falicov- Kimball model, the t-t{prime}-J model, and the Hubbard model. The spinless Falicov-Kimball model is analyzed in one-dimension. Perturbation theory and numerical techniques are employed to determine the phase diagram at zero temperature. A fractal structure is found where the ground-state changes (discontinuously) at each rational electron filling. The t-t{prime}-J model (strongly interacting limit of a Hubbard model) is studied on eight-site small clusters in the simple-cubic, body-centered-cubic, face-centered-cubic, and square lattices. Symmetry is used to simplify the problem and determine the exact many-body wavefunctions. Ground states are found that exhibit magnetic order or heavy-fermionic character. Attempts to extrapolate to the thermodynamic limit are also made. The Hubbard model is examined on an eight-site square-lattice cluster in the presence of and in the absence of a magnetic field'' that couples only to orbital motion. A new magnetic phase is discovered for the ordinary Hubbard model at half-filling. In the magnetic field'' case, it is found that the strongly frustrated Heisenberg model may be studied from adiabatic continuation of a tight-binding model (from weak to strong coupling) at one point. The full symmetries of the Hamiltonian are utilized to make the exact diagonalization feasibile. Finally, the presence of hidden'' extra symmetry for finite size clusters with periodic boundary conditions is analyzed for a variety of clusters. Moderately sized systems allow nonrigid transformations that map a lattice onto itself preserving its neighbor structure; similar operations are not present in smaller or larger systems. The additional symmetry requires particular representations of the space group to stick together explaining many puzzling degeneracies found in exact diagonalization studies.

  16. The influence of initial state fluctuations on heavy quark energy loss in relativistic heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Cao, Shanshan; Huang, Yajing; Qin, Guang-You; Bass, Steffen A.

    2015-12-01

    We study the effects of initial state fluctuations on the dynamical evolution of heavy quarks inside a quark-gluon plasma (QGP) created in relativistic heavy-ion collisions. The evolution of heavy quarks in QGP matter is described utilizing a modified Langevin equation that incorporates the contributions from both collisional and radiative energy loss. The spacetime evolution of the fireball medium is simulated with a (2 + 1)-dimensional viscous hydrodynamic model. We find that when the medium traversed by the heavy quark contains a fixed amount of energy, heavy quarks tend to lose more energy for greater fluctuations of the medium density. This may result in a larger suppression of heavy flavor observables in a fluctuating QGP matter than in a smooth one. The possibility of using hard probes to infer the information of initial states of heavy-ion collisions is discussed.

  17. Spin excitations and superconductivity in cuprate oxide and heavy electron superconductors

    NASA Astrophysics Data System (ADS)

    Pines, David

    1990-04-01

    The experimental evidence for a temperature-dependent build up of antiferromagnetic correlations between Cu 2+ planar spins in the normal state of cuprate oxide superconductors is reviewed, and a phenomenological one-component model, developed in collaboration with A. Millis and H. Monien, which appears capable of providing a quantitative account of existing experiments is described. A scaling law which relates the superconducting transaction temperature to the measurable spin-spin correlation length is proposed. The NMR experimental results in the superconducting state are shown to be consistent with d-wave pairing in a strong coupling superconductor. Comparison of the results of NMR experiments on the cuprate oxide and heavy electron superconductors reveals striking similarities. I conclude that the cuprate oxide superconductors are unconventional superconductors in which the superconductivity is of (primarily) electronic origin and results from an attractive interaction of antiferromagnetic character between itinerant quasiparticles in the spin antisymmetric channel, and discuss similarities and differences between cuprate oxide and heavy electron systems.

  18. Electronic structure and mass enhancement of the heavy fermion superconductor UPt 3

    NASA Astrophysics Data System (ADS)

    Wang, C. S.; Krakauer, H.; Pickett, W. E.

    1985-12-01

    The self-consistent general potential linearized augmented plane wave method has been applied to study the enegy bands of the heavy fermion superconductor UPt 3 within the local density approxination. We found 2.5 f-electrons per U atom and a f-band width of ≈1.9 eV pinned at the Fermi energy EF. An enhancement factor of 19 is deduced from the density of states at EF and the experimental linear coefficient of the specific heat. Possible sources of the renormalization are discussed based on available experimental information.

  19. Formation of heavy-Rydberg ion-pair states in Rydberg atom collisions with attaching targets

    NASA Astrophysics Data System (ADS)

    Wang, Changhao; Kelley, Michael; Buathong, Sitti; Dunning, F. Barry

    2014-05-01

    Electron transfer in collisions between K(np)Rydberg atoms and electron attaching molecules can lead to formation of heavy-Rydberg ion-pair states comprising a weakly-bound positive-negative ion pair orbiting at large internuclear separations. In the present work ion-pair states are created in a small collision cell and allowed to exit into an analysis region where their binding energy and velocity distributions are determined with the aid of electric-field-induced dissociation and a position sensitive detector. Ion pair production is analyzed using a Monte Carlo collision code that models both the initial Rydberg electron capture and the subsequent behavior of the product ion pair. The data demonstrate that collisions with SF6 and CCl4 lead to formation of long-lived ion pair states with a broad distribution of binding energies whose velocity distribution is strongly peaked in the forward direction. Research supported by the Robert A. Welch Foundation.

  20. Multiple-electron losses in uranium ion beams in heavy ion synchrotrons

    NASA Astrophysics Data System (ADS)

    Bozyk, L.; Chill, F.; Litsarev, M. S.; Tolstikhina, I. Yu.; Shevelko, V. P.

    2016-04-01

    Charge changing processes as the result of collisions with residual gas particles are the main cause of beam loss in high energy medium charge state heavy ion beams. To investigate the magnitude of this effect for heavy ion synchrotrons like the planned SIS100 at GSI, the multiple-electron and the total electron-loss cross sections are calculated for Uq+ ions, q = 10, 28, 40, 73, colliding with typical gas components H2, He, C, N2, O2, and Ar at ion energies E = 1 MeV/u-10 GeV/u. The total electron-capture cross sections for U28+ and U73+ ions interacting with these gases are also calculated. Most of these cross sections are new and presented for the first time. Calculated charge-changing cross sections are used to determine the ion-beam lifetimes τ for U28+ ions which agree well with the recently measured values at SIS18/GSI in the energy range E = 10-200 MeV/u. Using simulations made by the StrahlSim code with the reference ion U28+, it is found that in SIS100 the beam loss caused by single and multiple electron losses has only little impact on the residual gas density due to the high efficiency of the ion catcher system.

  1. Reliable Electronic Structure Calculations for Heavy Element Chemistry: Molecules Containing Actinides, Lanthanides, and Transition Metals

    SciTech Connect

    Marino, Maria, M.; Ermler, Walter C

    2006-01-27

    It is now possible to calculate many properties including the energetics (total bond dissociation energies or heats of formation) of molecules containing light elements to high accuracy by using correlation-consistent basis sets, coupled cluster theory and including additive corrections for core-valence and relativistic effects and careful treatment of the zero point energy. We propose to develop software for ab initio electronic structure calculations based on molecular orbital theory and density functional theory with the proper treatment of relativistic effects to study complexes of heavy elements in order to assist in understanding and predicting the chemistry of the actinides, lanthanides, and heavy transition metals, molecules critical to DOE missions including environmental management. The proposed work will focus on the development of these electronic structure methods and their implementation in software on advanced massively parallel processor (MPP) computer architectures capable of multi-tens of teraflops to petaflops. The core of the software will be developed within the NWChem and Columbus software suites. We propose to make the software broadly available so that other scientists can use these tools to address the complex environmental problems facing the Department of Energy's nuclear production sites as well as other waste sites in the Nation. Our implementation of relativistic quantum chemical methods for massively parallel computers will enable us to simulate the behavior of heavy-element compounds at the same type of level currently available for light-element compounds. In addition, this work will enable us to provide better methods for benchmarks of the additive energetic schemes currently available for light atom compounds. The theoretical and computational methodology so developed will be an invaluable supplement to current, very expensive experimental studies of the actinides, lanthanides, and radioactive heavy transition metal elements

  2. Effect of heavy-ion and electron irradiation on properties of Fe-based superconductors

    NASA Astrophysics Data System (ADS)

    Konczykowski, Marcin

    2013-03-01

    The introduction of defects by particle irradiation is used to reveal the role of disorder in matter, which is unavoidable in all crystalline solids. In superconductors defects introduce flux pinning, controlling critical current, Jc; as well as pair-breaking scattering, limiting the critical temperature, Tc. To elucidate defect related properties of Fe-based superconductors (FBS) we precede in two types of irradiation: heavy ion (6GeV Pb) to create disorder in the form of amorphous tracks and low temperature electron irradiation (2.5MeV at 20K) to create point like defects. Substantial increase of irreversible magnetization and an upward shift of the irreversibility line are observed after heavy ion irradiation of all FBS investigated to date. In BaK 122 , signatures of a Bose-glass vortex state; angular dependence and variable-range hopping flux creep are revealed. Remarkably, heavy ion irradiation does not depress Tc, however, point-like disorder introduced by electron irradiation does substantially. In isovalently substituted Ba(FeAs1 - xPx) 2 and Ba(Fe1 - x Rux As) 2 crystals, Tc decreases linearly with dose. Suppression to 40 % of initial value of Tc was achieved in Ba(FeAs1 - xPx) 2 . An increase of normal state resistivity is observed and correlated to depression of Tc. Change of superconducting gap structure with disorder was determined from penetration depth measurements, λ (T) dependence, at various stages of irradiation. Linear in T variation of pristine samples, indicative of the presence of nodes in gap, turned at low irradiation dose to exponential T variation, indicative of a fully gaped state. T2 variation of λ is observed at higher doses. This behaviour is incompatible with symmetry-imposed nodes of d-wave pairing but consistent with S + / - , S + / + mechanisms. This is the first observation of the impurity-induced node lifting expected in anisotropic s-wave superconductors

  3. Beam charge and current neutralization of high-charge-state heavy ions

    SciTech Connect

    Logan, B.G.; Callahan, D.A.

    1997-10-29

    High-charge-state heavy-ions may reduce the accelerator voltage and cost of heavy-ion inertial fusion drivers, if ways can be found to neutralize the space charge of the highly charged beam ions as they are focused to a target in a fusion chamber. Using 2-D Particle-In- Cell simulations, we have evaluated the effectiveness of two different methods of beam neutralization: (1) by redistribution of beam charge in a larger diameter, preformed plasma in the chamber, and (2), by introducing a cold-electron-emitting source within the beam channel at the beam entrance into the chamber. We find the latter method to be much more effective for high-charge-state ions.

  4. Studies of the ionization states of solar and galactic cosmic ray heavy nuclei

    NASA Technical Reports Server (NTRS)

    Biswas, S.

    1982-01-01

    Enhancement of abundances of heavy nuclei (e.g., Mg, Si, and Fe) at low energies relative to solar photospheric abundances and anomalously high abundances of iron relative to oxygen nuclei at low energies were recently discovered in solar energetic particles studied at low energy. These phenomena are not understood at present. The proposed experiment is designed to study the recently discovered anomalous component of low energy galactic cosmic ray ions of C, N, O, Ne, and Ca to Fe of energy 5- to 10-million electron volts per atomic mass unit in regard to their ionization states, composition, and intensity, and to study the ionization states of heavy elements from oxygen to iron in energetic solar particles emitted during flare events. The same detector system will serve for both studies, with the second objective being given priority if there are any solar particle events during the mission.

  5. Electrostatic solitary wave and double layer in a plasma with heavy ions and nonthermally distributed electrons

    SciTech Connect

    Choi, C.-R.; Min, K.-W.; Woo, M.-H.; Ryu, C.-M.

    2010-09-15

    The existence condition for bump and dip type, as well as double layer (DL), solutions of electrostatic solitary waves (ESWs) in a nonthermal electron plasma with heavy ions is investigated by a pseudopotential method. It is found that the nonthermality of electrons determines the existence of the DL solution and that the amplitude of ESWs is enhanced by the density of heavy ions. When the heavy ion density is beyond a certain critical value, ESWs and DLs cannot exist. It is also found that both the lower and upper critical Mach numbers are reduced by the presence of heavy ions.

  6. QED calculations in heavy many-electron atoms and one-electron quasi-molecules

    NASA Astrophysics Data System (ADS)

    Tupitsyn, I. I.; Safronova, M. S.; Kozlov, M. G.; Porsev, S. G.; Shabaev, V. M.

    2016-05-01

    Construction of simple one-electron approach to one-loop QED operator is an important task for the relativistic quantum theory of atoms and molecules. In this work we used two modifications of the model QED potential approach to calculations of the Lamb shift in many-electron atoms and one-electron quasi-molecules. The model potential is constructed as a sum of local and nonlocal (separable) potentials. The nonlocal part of the model potential was introduced to reproduce exactly the diagonal elements and also off-diagonal elements of the one-loop ab initio QED operator. The one-particle model QED operator was introduced in the Dirac-Fock and CI+MBPT relativistic calculations of the heavy and super-heavy atoms and in the calculations of the diatomic quasi-molecules. The comparison of the data obtained in different approaches to the one-loop QED operator is presented. Model QED potential is applied to calculate Lamb shift in the U91+- U92+ dimer. The results are compared with Ref..

  7. Heavy ion elastic recoil detection analysis set up for electronic sputtering studies

    NASA Astrophysics Data System (ADS)

    Ghosh, S.; Avasthi, D. K.; Tripathi, A.; Kabiraj, D.; Sugathan, P.; Chaudhary, G. K.; Barua, P.

    2006-04-01

    Heavy ion elastic recoil detection analysis (ERDA) set up with a large solid angle (greater than or similar to 4.8 msr) Delta E - E position-sensitive telescope detector is developed at Inter University Accelerator Centre as a dedicated facility for the study of electronic sputtering of thin films under swift heavy ion (SHI) irradiation. The detector consists of a gas ionization chamber (Delta E ) and a solid-state surface barrier detector ( E ) housed in a same assembly. The electronic sputtering yield (atoms/ion) is determined by analyzing on-line fluence-dependent ERDA data obtained from a variety of thin films. Large erosion (> 10 5 atoms/ion) of carbon from a-C:H by 150 MeV Ag 13+ ions, evolution of nitrogen (greater than or similar to 880 atoms/ion) from copper nitride and depletion of oxygen (greater than or similar to 1000 atoms/ion) from copper oxide film under 200 MeV Au 15+ ion impact are studied and reported in this work. The electronic sputtering of these materials is discussed on the basis of the thermal spike model of SHI and solid interaction.

  8. Theoretical studies of electronically excited states

    SciTech Connect

    Besley, Nicholas A.

    2014-10-06

    Time-dependent density functional theory is the most widely used quantum chemical method for studying molecules in electronically excited states. However, excited states can also be computed within Kohn-Sham density functional theory by exploiting methods that converge the self-consistent field equations to give excited state solutions. The usefulness of single reference self-consistent field based approaches for studying excited states is demonstrated by considering the calculation of several types of spectroscopy including the infrared spectroscopy of molecules in an electronically excited state, the rovibrational spectrum of the NO-Ar complex, core electron binding energies and the emission spectroscopy of BODIPY in water.

  9. Forward electron production in heavy ion-atom and ion-solid collisions

    SciTech Connect

    Sellin, I.A.

    1984-01-01

    A sharp cusp in the velocity spectrum of electrons, ejected in ion-atom and ion-solid collisions, is observed when the ejected electron velocity vector v/sub e/ matches that of the emergent ion vector v/sub p/ in both speed and direction. In ion-atom collisions, the electrons originate from capture to low-lying, projectile-centered continuum states (ECC) for fast bare or nearly bare projectiles, and from loss to those low-lying continuum states (ELC) when loosely bound projectile electrons are available. Most investigators now agree that ECC cusps are strongly skewed toward lower velocities, and exhibit full widths half maxima roughly proportional to v/sub p/ (neglecting target-shell effects, which are sometimes strong). A close examination of recent ELC data shows that ELC cusps are instead nearly symmetric, with widths nearly independent on v/sub p/ in the velocity range 6 to 18 a.u., a result only recently predicted by theory. Convoy electron cusps produced in heavy ion-solid collisions at MeV/u energies exhibit approximately velocity-independent widths very similar to ELC cusp widths. While the shape of the convoy peaks is approximately independent of projectile Z, velocity, and of target material, it is found that the yields in polycrystalline targets exhibit a strong dependence on projectile Z and velocity. While attempts have been made to link convoy electron production to binary ECC or ELC processes, sometimes at the last layer, or alternatively to a solid-state wake-riding model, our measured dependences of cusp shape and yield on projectile charge state and energy are inconsistent with the predictions of available theories. 10 references, 8 figures, 1 table.

  10. 119Sn NMR Studies of the Heavy-Electron Compound U3Au3Sn4

    NASA Astrophysics Data System (ADS)

    Takagi, Shigeru; Suzuki, Hiroyuki; Kusumoto, Takashi

    1993-03-01

    We have performed the 119Sn NMR, magnetic susceptibility, electrical resistivity and Hall effect measurements on a recently discovered heavy-electron compound U3Au3Sn4. The system is found to be in the incoherent Kondo state above about 40 K. Even under the presence of a large residual resistivity, the onset of coherence in the electronic system becomes evident below about 20 K in both ρ(T) and RH(T), but it does not manifest itself in T1-1(T). Observed almost T-independent T1-1(T) below about 20 K, however, is not considered as due to development of strongly q-dependent spin fluctuation (SF), since an analysis in terms of the Wilson ratio rather suggests a localized character of the SF.

  11. Z{sup +}(4430) and analogous heavy flavor states

    SciTech Connect

    Ding Guijun; Huang Wei; Liu Jiafeng; Yan Mulin

    2009-02-01

    The proximity of Z{sup +}(4430) to the D*D{sub 1} threshold suggests that it may be a D*D{sub 1} molecular state. The D*D{sub 1} system has been studied dynamically from quark model, and state mixing effect is taken into account by solving the multichannel Schroedinger equation numerically. We suggest the most favorable quantum number is J{sup P}=0{sup -}, if future experiments confirm Z{sup +}(4430) as a loosely bound molecule state. More precise measurements of Z{sup +}(4430) mass and width, partial wave analysis are helpful to understand its structure. The analogous heavy flavor mesons Z{sub bb}{sup +} and Z{sub bc}{sup ++} are studied as well, and the masses predicted in our model are in agreement with the predictions from potential model and QCD sum rule. We further apply our model to the DD* and DD* system. We find the exotic DD* bound molecule does not exist, while the 1{sup ++} DD* bound state solution can be found only if the screening mass {mu} is smaller than 0.17 GeV. The state mixing effect between the molecular state and the conventional charmonium should be considered to understand the nature of X(3872)

  12. Anomalous confined electron states in graphene superlattices

    SciTech Connect

    Anh Le, H.; Chien Nguyen, D.; Nam Do, V.

    2014-07-07

    We show that periodic scalar potentials can induce the localization of some electronic states in graphene. Particularly, localized states are found at energies outside the potential variation range and embedded in the continuum spectrum of delocalized ones. The picture of the connection of wave functions with typical symmetries defined in relevant-edge nanoribbons is employed to explain the formation of the electronic structure and to characterize/classify eigen-states in graphene superlattices.

  13. Electron cyclotron resonance ion source related development work for heavy-ion irradiation tests

    SciTech Connect

    Koivisto, H.; Suominen, P.; Tarvainen, O.; Virtanen, A.; Parkkinen, A.

    2006-03-15

    The European Space Agency (ESA) uses the facilities at the Accelerator Laboratory (Department of Physics, University of Jyvaeskylae: JYFL) for heavy-ion irradiation tests of electronic components. Electron cyclotron resonance ion source related development work has been carried out in order to meet the requirements set by the project. During the irradiation tests several beam changes are performed during the day. Therefore, the time needed for the beam changes has to be minimized. As a consequence, a beam cocktail having nearly the same m/q ratio is used. This makes it possible a quick tuning of the cyclotron to select the required ion for the irradiation. In addition to this requirement, very high charge states for the heavy elements are needed to reach a penetration depth of 100 {mu}m in silicon. In this article we present some procedures to optimize the ion source operation. We also present results of the first three-frequency heating tests. The main frequency of 14 GHz was fed from a klystron and both secondary frequencies were launched from a traveling-wave tube amplifier (TWTA). Two separate frequency generators were used simultaneously to provide different signals for the TWTA. During the test an improvement of about 20% was observed for {sup 84}Kr{sup 25+} and {sup 129}Xe{sup 30+} ion beams when the third frequency was applied.

  14. Nuclear-polarization correction to the bound-electron g factor in heavy hydrogenlike ions.

    PubMed

    Nefiodov, A V; Plunien, G; Soff, G

    2002-08-19

    The influence of nuclear polarization on the bound-electron g factor in heavy hydrogenlike ions is investigated. Numerical calculations are performed for the K- and L-shell electrons taking into account the dominant virtual nuclear excitations. This determines the ultimate limit for tests of QED utilizing measurements of the bound-electron g factor in highly charged ions. PMID:12190457

  15. Spur decay kinetics of the solvated electron in heavy water radiolysis.

    SciTech Connect

    Bartels, D. M.; Gosztola, D.; Jonah, C. D.; Chemistry

    2001-08-30

    Spur decay kinetics of the hydrated electron following picosecond pulse radiolysis of heavy water have been measured using a time-correlated absorption spectroscopy (TCAS) technique. The TCAS data collected for the first 40 ns of the decay was matched up with single-shot transient digitizer data out to microsecond time scales. The decay shape in heavy water looks exactly like the decay in light water except in the first 10 ns. The 'time zero' solvated electron yield in heavy water radiolysis must be approximately 7% larger than in light water, to match the best available scavenger product measurements. We propose an explanation in terms of the larger distances traveled by electrons in heavy water prior to localization. The implication is that presolvated H{sub 2}O{sup +} 'holes' are very efficient scavengers for the presolvated conduction band electrons.

  16. Secondary electron background produced by heavy nuclei in a multiwire proportional counter hodoscope

    NASA Technical Reports Server (NTRS)

    Morgan, S. H., Jr.; Watts, J. W., Jr.; Schwille, H.; Pollvogt, U.

    1974-01-01

    The secondary electron background produced by heavy nuclei in a multiwire proportional counter hodoscope is calculated using both a simplified and a more complete Monte Carlo model. These results are compared with experimental data from a small multiwire proportional counter hodoscope operated in a 530 MeV/nucleon accelerator beam of nitrogen nuclei. Estimates of the secondary electron background produced by heavy relativistic nuclei are presented along with the detailed results from calculations of energy deposition in the hodoscope counter cells.

  17. Low-temperature radiation cracking of heavy oil under continuous and pulse electron irradiation

    NASA Astrophysics Data System (ADS)

    Zaikin, Yuriy A.

    2016-05-01

    The dependence of the chain reaction parameters on the conditions of pulse and continuous electron irradiation is analyzed for the case of low-temperature radiation cracking of heavy oils. The specificity of kinetics and yields of light products after radiation cracking are considered in the cases of continuous and pulse irradiation. Theoretical calculations are compared with experimental data on electron irradiation of heavy oil in different conditions.

  18. Dispersion of heavy ion deposited energy in nanometric electronic devices: Experimental measurements and simulation possibilities

    NASA Astrophysics Data System (ADS)

    Raine, M.; Gaillardin, M.; Paillet, P.; Duhamel, O.; Martinez, M.; Bernard, H.

    2015-12-01

    The dispersion of heavy ion deposited energy is explored in nanometric electronic devices. Experimental data are reported, in a large thin SOI diode and in a SOI FinFET device, showing larger distributions of collected charge in the nanometric volume device. Geant4 simulations are then presented, using two different modeling approaches. Both of them seem suitable to evaluate the dispersion of deposited energy induced by heavy ion beams in advanced electronic devices with nanometric dimensions.

  19. Energy Approach to Resonance states of Compound Superheavy Nucleus and EPPP in Heavy Nuclei Collisions

    SciTech Connect

    Glushkov, Alexander V.

    2005-10-26

    A consistent unified energy approach (operator perturbation theory) is used for numerical calculations of the electron-positron pair production cross-section in heavy nuclei collisions. Resonance phenomena in the nuclear subsystem lead to the structurization of the positron spectrum produced. The positron spectrum narrow peaks are treated as resonance states of the compound superheavy nucleus. Calculation results for the differential cross-sections of the U-U collision energies E1 (E1=162.0keV- third s-resonance; E1=247.6keV- the fourth s-resonance) are presented.

  20. Two-gluino bound states and heavy quarkonium

    SciTech Connect

    Zuk, J.; Joshi, G.C.; Wignall, J.W.G.

    1983-10-01

    A supersymmetric octet QCD, incorporating interacting gluons and gluinos, is formulated and used to discuss the features of two-gluino bound states. The short-range gluino-gluino potential is calculated and it is assumed that the complete potential, including the color-confining part, has the same form as the quark-antiquark potential but multiplied by the color factor derived for the short-range part. A spin-dependent mass formula based on a quark-antiquark potential of the Martin single-power type is fitted to the known triplet and singlet states of heavy quarkonia and is then used to make predictions of the mass spectra of /sup 3/S, /sup 1/P, and /sup 3/D gluino-gluino bound states. It is found that the relative energy spacings of these states are almost independent of gluino mass m/sub lambda/ for m/sub lambda/> or approx. =5 GeV, the experimental lower limit.

  1. Solid-state sintering of tungsten heavy alloys

    SciTech Connect

    Gurwell, W.E.

    1994-10-01

    Solid-state sintering is a technologically important step in the fabrication of tungsten heavy alloys. This work addresses practical variables affecting the sinterability: powder particle size, powder mixing, and sintering temperature and time. Compositions containing 1 to 10 micrometer ({mu}M) tungsten (W) powders can be fully densified at temperatures near the matrix solidus. Blending with an intensifier bar provided good dispersion of elemental powders and good as-sintered mechanical properties under adequate sintering conditions. Additional ball milling increases powder bulk density which primarily benefits mold and die filling. Although fine, 1 {mu}m W powder blends have high sinterability, higher as-sintered ductilities are reached in shorter sintering times with coarser, 5 {mu}m W powder blends; 10{mu}m W powder blends promise the highest as-sintered ductilities due to their coarse microstructural W.

  2. Swift heavy ion induced electron emission from solids

    NASA Astrophysics Data System (ADS)

    Rothard, Hermann; Lanzanò, Gaetano; Gervais, Benoit; De Filippo, Enrico; Caron, Michel; Beuve, Michael

    2015-07-01

    We briefly summarize the results of numerous experiments performed at GANIL aimed at measuring electron yields and doubly differential yields (energy or velocity spectra at different ejection angles, angular distributions). These studies, supported by theoretical investigations and numerical simulations, contributed decisively to our understanding of the very first step in energy deposition in matter, i.e. ionization and subsequent electron transport through condensed matter. The emitted electron spectrum contains a rich variety of features including binary encounter electrons (BEE), convoy electrons (CE), Auger electrons (AE) and the low-energy peak of “secondary” electrons (SE).

  3. Heavy flavor electron RAA and υ2 in event-by-event relativistic hydrodynamics

    NASA Astrophysics Data System (ADS)

    Prado, Caio A. G.; Cosentino, Mauro R.; Munhoz, Marcelo G.; Noronha, Jorge; Suaide, Alexandre A. P.

    2016-04-01

    In this work we investigate how event-by-event hydrodynamics fluctuations affect the nuclear suppression factor and elliptic flow of heavy flavor mesons and non-photonic electrons. We use a 2D+1 Lagrangian ideal hydrodynamic code [1, 2] on an event-by-event basis in order to compute local temperature and flow profiles. Using a strong coupling inspired energy loss parametrization [3] on top of the evolving space-time energy density distributions we are able to propagate the heavy quarks inside the medium until the freeze-out temperature is reached and a Pythia [4] modeling of hadronization takes place. The resulting D0 and heavy-flavor electron yield is compared with recent experimental data for R AA and υ 2 from the STAR and PHENIX collaborations [5-7]. In addition we present preditions for the higher order Fourier harmonic coefficients υ3(pt) of heavy-flavor electrons at Rhic’s collisions.

  4. United States commitment to heavy lift launch vehicles

    NASA Astrophysics Data System (ADS)

    Gabris, Edward A.

    Observers of the United States' space program will note progress toward the development of a new launch system capable of supporting the nation's future space missions. The process of defining mission requirements, developing technically and politically acceptable solutions, making policy decisions, and developing budget support in a democratic society is protracted, but eventually yields decisions that represent the public interest. The consensus developing within the United States on a new launch capability including heavy-lift is embodied in the Joint NASA/DoD National Launch System. This launch vehicle concept has emerged after more than five years of studies by NASA, the DoD and every major industrial aerospace contractor in the U.S. In July 1991, Vice President Quayle, in his capacity as Chairman of the National Space Council stated the Nation's commitment to support of the NLS. This paper reviews progress to date, and the involvement of the four major constituencies; the Executive Branch operating through the National Space Council, the Legislative Branch, the various elements of the DoD, and NASA. The evolution of launch system "requirements", along with the form, content and rationale for the various decisions that have been made will be described and discussed.

  5. Design study of primary ion provider for relativistic heavy ion collider electron beam ion source.

    PubMed

    Kondo, K; Kanesue, T; Tamura, J; Okamura, M

    2010-02-01

    Brookhaven National Laboratory has developed the new preinjector system, electron beam ion source (EBIS) for relativistic heavy ion collider (RHIC) and National Aeronautics and Space Administration Space Radiation Laboratory. Design of primary ion provider is an essential problem since it is required to supply beams with different ion species to multiple users simultaneously. The laser ion source with a defocused laser can provide a low charge state and low emittance ion beam, and is a candidate for the primary ion source for RHIC-EBIS. We show a suitable design with appropriate drift length and solenoid, which helps to keep sufficient total charge number with longer pulse length. The whole design of primary ion source, as well as optics arrangement, solid targets configuration and heating about target, is presented. PMID:20192366

  6. Nearly free electron states in MXenes

    NASA Astrophysics Data System (ADS)

    Khazaei, Mohammad; Ranjbar, Ahmad; Ghorbani-Asl, Mahdi; Arai, Masao; Sasaki, Taizo; Liang, Yunye; Yunoki, Seiji

    2016-05-01

    Using a set of first-principles calculations, we studied the electronic structures of two-dimensional transition metal carbides and nitrides, so called MXenes, functionalized with F, O, and OH. Our projected band structures and electron localization function analyses reveal the existence of nearly free electron (NFE) states in a variety of MXenes. The NFE states are spatially located just outside the atomic structure of MXenes and are extended parallel to the surfaces. Moreover, we found that the OH-terminated MXenes offer the NFE states energetically close to the Fermi level. In particular, the NFE states in some of the OH-terminated MXenes, such as T i2C (OH) 2,Z r2C (OH) 2,Z r2N (OH) 2,H f2C (OH) 2,H f2N (OH) 2,N b2C (OH) 2 , and T a2C (OH) 2 , are partially occupied. This is in remarkable contrast to graphene, graphane, and Mo S2 , in which their NFE states are located far above the Fermi level and thus they are unoccupied. As a prototype of such systems, we investigated the electron transport properties of H f2C (OH) 2 and found that the NFE states in H f2C (OH) 2 provide almost perfect transmission channels without nuclear scattering for electron transport. Our results indicate that these systems might find applications in nanoelectronic devices. Our findings provide new insights into the unique electronic band structures of MXenes.

  7. Fermionic thermocoherent state: Efficiency of electron transport

    NASA Astrophysics Data System (ADS)

    Karmakar, Anirban; Gangopadhyay, Gautam

    2016-02-01

    On the basis of the fermionic coherent state of Cahill and Glauber [Phys. Rev. A 59, 1538 (1999)], 10.1103/PhysRevA.59.1538, we have introduced here the fermionic thermocoherent state in terms of the quasiprobability distribution which shows the appropriate thermal and coherent limits as in the bosonic case or the Glauber-Lachs state. It is shown that the fermionic thermocoherent state can be realized as a displaced thermal state of fermions. Its relation with the fermionic displaced number state and the fermion-added coherent state are explored in the spirit of the bosonic case. We have investigated the nature of the average current and the suppression of noise due to the thermocoherent character of the source. The theory is applied to the problem of electronic conduction. A modification of the Landauer conductance formula is suggested which reflects the role of nonzero coherence of the source in electron transport.

  8. Heavy Rydberg behaviour in high vibrational levels of some ion-pair states of the halogens and inter-halogens

    SciTech Connect

    Donovan, Robert J. E-mail: tr01@staffmail.ed.ac.uk; Lawley, Kenneth P. Ridley, Trevor E-mail: tr01@staffmail.ed.ac.uk

    2015-05-28

    We report the identification of heavy Rydberg resonances in the ion-pair spectra of I{sub 2}, Cl{sub 2}, ICl, and IBr. Extensive vibrational progressions are analysed in terms of the energy dependence of the quantum defect δ(E{sub b}) rather than as Dunham expansions. This is shown to define the heavy Rydberg region, providing a more revealing fit to the data with fewer coefficients and leads just as easily to numbering data sets separated by gaps in the observed vibrational progressions. Interaction of heavy Rydberg states with electronic Rydberg states at avoided crossings on the inner wall of the ion-pair potential is shown to produce distinctive changes in the energy dependence of δ(E{sub b}), with weak and strong interactions readily distinguished. Heavy Rydberg behaviour is found to extend well below near-dissociation states, down to vibrational levels ∼18 000-20 000 cm{sup −1} below dissociation. The rapid semi-classical calculation of δ(E{sub b}) for heavy Rydberg states is emphasised and shows their absolute magnitude to be essentially the volume of phase space excluded from the vibrational motion by avoiding core-core penetration of the ions.

  9. Description of electronic excited states using electron correlation operator.

    PubMed

    Nichols, Bryan; Rassolov, Vitaly A

    2013-09-14

    The electron correlation energy in a chemical system is defined as a difference between the energy of an exact energy for a given Hamiltonian, and a mean-field, or single determinant, approximation to it. A promising way to model electron correlation is through the expectation value of a linear two-electron operator for the Kohn-Sham single determinant wavefunction. For practical reasons, it is desirable for such an operator to be universal, i.e., independent of the positions and types of nuclei in a molecule. The correlation operator models the effect of electron correlation on the interaction energy in a electron pair. We choose an operator expanded in a small number of Gaussians as a model for electron correlation, and test it by computing atomic and molecular adiabatic excited states. The computations are performed within the Δ Self-Consistent Field (ΔSCF) formalism, and are compared to the time-dependent density functional theory model with popular density functionals. The simplest form of the correlation operator contains only one parameter derived from the helium atom ground state correlation energy. The correlation operator approach significantly outperforms other methods in computation of atomic excitation energies. The accuracy of molecular excitation energies computed with the correlation operator is limited by the shortcomings of the ΔSCF methodology in describing excited states. PMID:24050332

  10. Intense steady state electron beam generator

    DOEpatents

    Hershcovitch, Ady; Kovarik, Vincent J.; Prelec, Krsto

    1990-01-01

    An intense, steady state, low emittance electron beam generator is formed by operating a hollow cathode discharge plasma source at critical levels in combination with an extraction electrode and a target electrode that are operable to extract a beam of fast primary electrons from the plasma source through a negatively biased grid that is critically operated to repel bulk electrons toward the plasma source while allowing the fast primary electrons to move toward the target in the desired beam that can be successfully transported for relatively large distances, such as one or more meters away from the plasma source.

  11. Intense steady state electron beam generator

    DOEpatents

    Hershcovitch, A.; Kovarik, V.J.; Prelec, K.

    1990-07-17

    An intense, steady state, low emittance electron beam generator is formed by operating a hollow cathode discharge plasma source at critical levels in combination with an extraction electrode and a target electrode that are operable to extract a beam of fast primary electrons from the plasma source through a negatively biased grid that is critically operated to repel bulk electrons toward the plasma source while allowing the fast primary electrons to move toward the target in the desired beam that can be successfully transported for relatively large distances, such as one or more meters away from the plasma source. 2 figs.

  12. Electron spin resonance and electronic structure of vanadyl-porphyrin in heavy crude oils.

    PubMed

    Espinosa P, M; Campero, A; Salcedo, R

    2001-08-27

    A study of vanadyl-porphyrin by electron spin resonance (ESR) was carried out looking for answers about the role that the central V=O ion plays when these kinds of molecules are present in heavy crude oils. The eigenvalues of the linear combination of atomic orbitals (LCAO) were obtained from the experimental values of g and parameters (ESR). The contributions to the molecular orbitals that describe the various energy levels of vanadyl ion were also obtained for the porphyrin species. The trends of the degree of covalent character of the metal-ligand bonds and the length of the vanadium-oxygen chemical bond are discussed. It is interesting to note that the Fermi contact term, K(eff), is essentially constant for all samples investigated, and it was found to be independent of the calculated electron delocalization (1 - delta(2)) and shows only little variation among the three different samples of oil. The orbital energies derived from our ESR study qualitatively agree with those predicted from MO theory for synthetic vanadyl-porphyrins. PMID:11511197

  13. Heavy ion charge-state distribution effects on energy loss in plasmas

    NASA Astrophysics Data System (ADS)

    Barriga-Carrasco, Manuel D.

    2013-10-01

    According to dielectric formalism, the energy loss of the heavy ion depends on its velocity and its charge density. Also, it depends on the target through its dielectric function; here the random phase approximation is used because it correctly describes fully ionized plasmas at any degeneracy. On the other hand, the Brandt-Kitagawa (BK) model is employed to depict the projectile charge space distribution, and the stripping criterion of Kreussler is used to determine its mean charge state . This latter criterion implies that the mean charge state depends on the electron density and temperature of the plasma. Also, the initial charge state of the heavy ion is crucial for calculating inside the plasma. Comparing our models and estimations with experimental data, a very good agreement is found. It is noticed that the energy loss in plasmas is higher than that in the same cold gas cases, confirming the well-known enhanced plasma stopping (EPS). In this case, EPS is only due to the increase in projectile effective charge Qeff, which is obtained as the ratio between the energy loss of each heavy ion and that of the proton in the same plasma conditions. The ratio between the effective charges in plasmas and in cold gases is higher than 1, but it is not as high as thought in the past. Finally, another significant issue is that the calculated effective charge in plasmas Qeff is greater than the mean charge state , which is due to the incorporation of the BK charge distribution. When estimations are performed without this distribution, they do not fit well with experimental data.

  14. Dynamical heavy-quark recombination and the non-photonic single electron puzzle at RHIC

    SciTech Connect

    Ayala, Alejandro; Magnin, J.; Montano, Luis Manuel; Toledo Sanchez, G.

    2011-04-26

    We show that the single, non-photonic electron nuclear modification factor R{sub AA}{sup e} is affected by the thermal enhancement of the heavy-baryon to heavy-meson ratio in relativistic heavy-ion collisions with respect to proton-proton collisions. We make use of the dynamical quark recombination model to compute such ratio and show that this produces a sizable suppression factor for the R{sub AA}{sup e} at intermediate transverse momenta. We argue that such suppression factor needs to be considered, in addition to the energy loss contribution, in calculations of R{sub AA}{sup e}.

  15. X-ray solution scattering of squid heavy meromyosin: strengthening the evidence for an ancient compact off state.

    PubMed

    Gillilan, Richard E; Kumar, V S Senthil; O'Neall-Hennessey, Elizabeth; Cohen, Carolyn; Brown, Jerry H

    2013-01-01

    The overall conformations of regulated myosins or heavy meromyosins from chicken/turkey, scallop, tarantula, limulus, and scorpion sources have been studied by a number of techniques, including electron microscopy, sedimentation, and pulsed electron paramagnetic resonance. These studies have indicated that the binding of regulatory ions changes the conformation of the molecule from a compact shape found in the "off" state of the muscle to extended relationships between the tail and independently mobile heads that predominate in the "on" state. Here we strengthen the argument for the generality of this conformational change by using small angle X-ray scattering on heavy meromyosin from squid. Small angle X-ray scattering allows the protein to be visualized in solution under mild and relatively physiological conditions, and squid differs from the other species studied by at least 500 million years of evolution. Analysis of the data indicates that upon addition of Ca(2+) the radius of gyration increases. Differences in the squid "on" and "off" states are clearly distinguishable as bimodal and unimodal pair distance distribution functions respectively. These observations are consistent with a Ca(2+)-free squid heavy meromyosin that is compact, but which becomes extended when Ca(2+) is bound. Further, the scattering profile derived from the current model of tarantula heavy meromyosin in the "off" state is in excellent agreement with the measured "off" state scattering profile for squid heavy meromyosin. The previous and current studies together provide significant evidence that regulated myosin's compact off-state conformation is an ancient trait, inherited from a common ancestor during divergent evolution. PMID:24358137

  16. Two electronic states in spherical quantum nanolayer

    NASA Astrophysics Data System (ADS)

    Aghekyan, N. G.; Kazaryan, E. M.; Kostanyan, A. A.; Sarkisyan, H. A.

    2010-10-01

    In this paper two electronic states in spherical quantum nanolayer are discussed. The Coulomb interaction between the electrons is discussed as perturbation. For confinement potential of the nanolayer the three-dimensional radial analog of Smorodinsky-Winternitz potential is considered. The problem is discussed within the frameworks of Russell-Saunders coupling scheme, thus, the spin-orbit interaction is considered weak. Therefore the eigenfunctions of the system is represented as a multiplication of its coordinate wave function and spin wave function. For this system the analogue of helium atom theory is represented. The eigenfunctions and energy states are obtained for one and two electron cases in the spherical quantum nanolayer. For the spherical nanolayer the dependence of perturbation energy, unperturbed system energy and the total energy for the ground state upon the inner radius is represented when the outer radius is fixed.

  17. Heavy-ion collisions and the nuclear equation of state

    SciTech Connect

    Keane, D.

    1992-01-01

    The overall goal of this project is to study nucleus-nucleus collisions experimentally at intermediate and relativistic energies, with emphasis on measurement and interpretation of correlation effects that provide insight into the nuclear phase diagram and the nuclear equation of state. During the past year, the PI has been on leave at Lawrence Berkeley Lab and has worked on this research project full-time. A large fraction of the effort of the PI and graduate students has gone into preparing for experiments using the Time Projection Chamber at LBL's Bevalac accelerator; in March 1992, this device successfully took data in production mode for the first time, and the first physics analysis is now under way. The PI has carried out simulations that help to define the physics performance and engineering specifications of the recently-approved STAR detector for the Relativistic Heavy Ion Collider, and has identified a new capability of this device with the potential for being an important quark-gluon plasma signature. A Postdoctoral Fellow, jointly supported by this grant and Kent State University, has been recruited to augment these efforts. Since May 1991, 11 journal papers have been published or submitted for publication; 2 conference proceedings and 9 reports or abstracts have also been published during the past year. One paper in Phys. Rev. Left., one in Phys. Rev. C, and one conference proceedings are based on the thesis project of one of the PI's Ph.D. students who is expected to graduate later this year. Partly in response to the impending closure of the Bevalac, the PI's group has recently joined the NA49 experiment at CERN.

  18. Floating electron states in covalent semiconductors.

    PubMed

    Matsushita, Yu-ichiro; Furuya, Shinnosuke; Oshiyama, Atsushi

    2012-06-15

    We report first-principles electronic-structure calculations that clarify the floating nature of electron states in covalent semiconductors. It is found that wave functions of several conduction- and valence-band states, including the conduction-band minima, do not distribute near atomic sites, as was taken for granted, but float in interstitial channels in most semiconductors. The directions and shapes of the interstitial channels depend on the crystal symmetry so that mysterious variation of the energy gaps in SiC polymorphs is naturally explained by considering the floating nature. PMID:23004300

  19. Electronically excited states of PANH anions.

    PubMed

    Theis, Mallory L; Candian, Alessandra; Tielens, Alexander G G M; Lee, Timothy J; Fortenberry, Ryan C

    2015-06-14

    The singly deprotonated anion derivatives of nitrogenated polycyclic aromatic hydrocarbons (PANHs) are investigated for their electronically excited state properties. These include single deprotonation of the two unique arrangements of quinoline producing fourteen different isomers. This same procedure is also undertaken for single deprotonation of the three nitrogenation isomers of acridine and the three of pyrenidine. It is shown quantum chemically that the quinoline-class of PANH anion derivatives can only produce a candidate dipole-bound excited state each, a state defined as the interaction of an extra electron with the dipole moment of the corresponding neutral. However, the acridine- and pyrenidine-classes possess valence excited states as well as the possible dipole-bound excited states where the latter is only possible if the dipole moment is sufficiently large to retain the extra electron; the valence excitation is independent of the radical dipolar strength. As a result, the theoretical vertically computed electronic spectra of deprotonated PANH anion derivatives is fairly rich in the 1.5 eV to 2.5 eV range significantly opening the possibilities for these molecules to be applied to longer wavelength studies of visible and near-IR spectroscopy. Lastly, the study of these systems is also enhanced by the inclusion of informed orbital arrangements in a simply constructed basis set that is shown to be more complete and efficient than standard atom-centered functions. PMID:25975430

  20. Quest for the Origin of Heavy Fermion Behavior in d-Electron Systems

    NASA Astrophysics Data System (ADS)

    Miyazaki, Masanori; Yamauchi, Ichihiro; Kadono, Ryosuke

    2016-09-01

    Spin fluctuation is presumed to be one of the key properties in understanding the microscopic origin of heavy-fermion-like behavior in the class of transition-metal compounds, including LiV2O4, Y(Sc)Mn2, and YMn2Zn20. In this review, we demonstrate by our recent study of muon spin rotation/relaxation that the temperature (T) dependence of the longitudinal spin relaxation rate (λ ≡ 1/T1) in these compounds exhibits a common trend of leveling off to a constant value (λ ˜ const.) below a characteristic temperature, T*. This is in marked contrast to the behavior predicted for normal metals from the Korringa relation, λ ∝ T/ν, where the spin fluctuation rate (ν) in the Pauli paramagnetic state is given as a constant, ν ≃ 1/[hD(EF)] [with D(EF) being the density of states at the Fermi energy]. Thus, the observed behavior of λ implies that the spin fluctuation rate becomes linearly dependent on temperature, ν ∝ T, suggesting that heavy quasiparticles develop in a manner satisfying D(EF) ∝ (m*)σ ∝ 1/T at lower temperatures (σ determined by the electronic dispersion). Considering that the theory of spin correlation for intersecting Hubbard chains as a model of pyrochlore lattice predicts ν ∝ T, our finding strongly indicates the crucial role of t2g bands which preserve the one-dimensional character at low energies due to the geometrical frustration specific to the undistorted pyrochlore lattice.

  1. State-specific heavy-atom effect on intersystem crossing processes in 2-thiothymine: A potential photodynamic therapy photosensitizer

    NASA Astrophysics Data System (ADS)

    Cui, Ganglong; Fang, Wei-hai

    2013-01-01

    Thiothymidine has a potential application as a photosensitizer in cancer photodynamic therapy (PDT). As the chromophore of thiothymidine, 2-thiothymine exhibits ultrahigh quantum yield of intersystem crossing to the lowest triplet state T1 (ca. 100%), which contrasts with the excited-state behavior of the natural thymine that dissipates excess electronic energy via ultrafast internal conversion to the ground state. In this work, we employed high-level complete-active space self-consistent field and its second-order perturbation methods to explore the photophysical mechanism of a 2-thiothymine model. We have optimized the minimum energy structures in the low-lying seven electronic states, as well as ten intersection points. On the basis of the computed potential energy profiles and spin-orbit couplings, we proposed three competitive, efficient nonadiabatic pathways to the lowest triplet state T1 from the initially populated singlet state S2. The suggested mechanistic scenario explains well the recent experimental phenomena. The origin responsible for the distinct photophysical behaviors between thymine and 2-thiothymine is ascribed to the heavy-atom effect, which is significantly enhanced in the latter. Additionally, this heavy-atom effect is found to be state-specific, which could in principle be used to tune the photophysics of 2-thiothymine. The present high-level electronic structure calculations also contribute to understand the working mechanism of thiothymidine in PDT.

  2. Heavy ion beam-ionosphere interactions - Electron acceleration

    NASA Technical Reports Server (NTRS)

    Kaufmann, R. L.; Arnoldy, R. L.; Moore, T. E.; Kintner, P. M.; Cahill, L. J., Jr.

    1985-01-01

    Moore et al. (1982) described a number of unexpected effects which were observed during the first Argon Release Controlled Study (ARCS 1, or rocket flight 29:014). The present paper provides a description of detailed analyses of the interaction of the argon beam with the ionosphere. An important feature of the considered test was that all detectors and the Ar(+) gun remained attached to the rocket throughout the flight. It is pointed out that the most dramatic effect of ion gun operation on ARCS 1 involved large changes in the fluxes of electrons with energies below about 600 eV. The observations are discussed, taking into account the distribution functions, azimuth dependence, and electron and ion trajectories. Attention is given to the perpendicular ion beam, the parallel ion beam, the acceleration of downgoing and upgoing electrons, and aspects of wave generation.

  3. Heavy ion beam-ionosphere interactions - Electron acceleration

    NASA Astrophysics Data System (ADS)

    Kaufmann, R. L.; Arnoldy, R. L.; Moore, T. E.; Kintner, P. M.; Cahill, L. J., Jr.

    1985-10-01

    Moore et al. (1982) described a number of unexpected effects which were observed during the first Argon Release Controlled Study (ARCS 1, or rocket flight 29:014). The present paper provides a description of detailed analyses of the interaction of the argon beam with the ionosphere. An important feature of the considered test was that all detectors and the Ar(+) gun remained attached to the rocket throughout the flight. It is pointed out that the most dramatic effect of ion gun operation on ARCS 1 involved large changes in the fluxes of electrons with energies below about 600 eV. The observations are discussed, taking into account the distribution functions, azimuth dependence, and electron and ion trajectories. Attention is given to the perpendicular ion beam, the parallel ion beam, the acceleration of downgoing and upgoing electrons, and aspects of wave generation.

  4. Photoemission and the electronic properties of heavy fermions -- limitations of the Kondo model

    SciTech Connect

    Joyce, J.J.; Arko, A.J.; Andrews, A.B.

    1993-09-01

    The electronic properties of Yb-based heavy fermions have been investigated by means of high resolution synchrotron radiation photoemission and compared with predictions of the Kondo model. The Yb heavy fermion photoemission spectra show massive disagreement with the Kondo model predictions (as calculated within the Gunnarsson-Schonhammer computational method). Moreover, the Yb heavy fermion photoemission spectra give very strong indications of core-like characteristics and compare favorable to purely divalent Yb metal and core-like Lu 4f levels. The heavy fermions YbCu{sub 2}Si{sub 2}, YbAgCu{sub 4} and YbAl{sub 3} were measured and shown to have lineshapes much broader and deeper in binding energy than predicted by the Kondo model. The lineshape of the bulk component of the 4f emission for these three heavy fermion materials was compared with that from Yb metal and the Lu 4f levels in LuAl{sub 3}, the heavy fermion materials show no substantive spectroscopic differences from simple 4f levels observed in Yb metal and LuAl{sub 3}. Also, the variation with temperature of the 4f fineshape was measured for Yb metal and clearly demonstrates that phonon broadening plays a major role in 4f level lineshape analysis and must be accounted for before considerations of correlated electron resonance effects are presumed to be at work.

  5. Electronics: State of the Art No. 2.

    ERIC Educational Resources Information Center

    Gosling, W.

    1979-01-01

    Reviewed is a brief history of electronics technology, from the early beginnings of vacuum devices to development of solid state devices, silicon fabrication in the use of transistors, and integrated circuits. Educational needs at the university or polytechnic level are discussed. (CS)

  6. Accessing the Triplet State in Heavy-Atom-Free Perylene Diimides.

    PubMed

    Yu, Zhenyi; Wu, Yishi; Peng, Qian; Sun, Chunlin; Chen, Jianwei; Yao, Jiannian; Fu, Hongbing

    2016-03-24

    Previous studies of perylenediimides (PDIs) mostly utilized the lowest singlet excited state S1 . Generation of a triplet excited state (T1 ) in PDIs is important for applications ranging from photodynamic therapy to photovoltaics; however, it remains a formidable task. Herein, we developed a heavy-atom-free strategy to prompt the T1 ←S1 intersystem crossing (ISC) by introducing electron-donating aryl (Ar) groups at the head positions of an electron-deficient perylenediimide (PDI) core. We found that the ISC efficiency increases from 8 to 54 % and then to 86 % by increasing the electron-donating ability of head-substituted aryl groups from phenyl (p-PDI) to methoxyphenyl (MeO-PDI) and then to methylthioxyphenyl (MeS-PDI). By enhancing the intramolecular charge-transfer (ICT) interaction from p-PDI to MeO-PDI, and then to MeS-PDI, singlet oxygen generation via energy-transfer reactions from T1 of PDIs to (3)O2 was demonstrated with the highest yield of up to 80 %. These results provide guidelines for developing new triplet-generating PDIs and related rylene diimides for optoelectronic applications. PMID:26853213

  7. Phase stability in heavy f-electron metals from first-principles theory

    SciTech Connect

    Soderlind, P

    2005-11-17

    The structural phase stability of heavy f-electron metals is studied by means of density-functional theory (DFT). These include temperature-induced transitions in plutonium metal as well as pressure-induced transitions in the trans-plutonium metals Am, Cm, Bk, and Cf. The early actinides (Th-Np) display phases that could be rather well understood from the competition of a crystal-symmetry breaking mechanism (Peierls distortion) of the 5f states and electrostatic forces, while for the trans-plutonium metals (Am-Cf) the ground-state structures are governed by 6d bonding. We show in this paper that new physics is needed to understand the phases of the actinides in the volume range of about 15-30 {angstrom}{sup 3}. At these volumes one would expect, from theoretical arguments made in the past, to encounter highly complex crystal phases due to a Peierls distortion. Here we argue that the symmetry reduction associated with spin polarization can make higher symmetry phases competitive. Taking this into account, DFT is shown to describe the well-known phase diagram of plutonium and also the recently discovered complex and intriguing high-pressure phase diagrams of Am and Cm. The theory is further applied to investigate the behaviors of Bk and Cf under compression.

  8. Two-photon absorption of few-electron heavy ions

    SciTech Connect

    Surzhykov, A.; Indelicato, P.; Santos, J. P.; Amaro, P.; Fritzsche, S.

    2011-08-15

    The two-photon absorption of few-electron ions has been studied by using second-order perturbation theory and Dirac's relativistic equation. Within this framework, the general expressions for the excitation cross sections and rates are derived including a full account of the higher-order multipole terms in the expansion of the electron-photon interaction. While these expressions can be applied to any ion, independent of its particular shell structure, detailed computations are carried out for the two-photon absorption of hydrogen-, helium-, and berylliumlike ions and are compared with the available theoretical and experimental data. The importance of relativistic and nondipole effects in the analysis and computation of induced two-photon transitions is pointed out. Moreover, we discuss the potential of these transitions for atomic parity-violation studies in the high-Z domain.

  9. Heavy fermions. Unconventional Fermi surface in an insulating state.

    PubMed

    Tan, B S; Hsu, Y-T; Zeng, B; Hatnean, M Ciomaga; Harrison, N; Zhu, Z; Hartstein, M; Kiourlappou, M; Srivastava, A; Johannes, M D; Murphy, T P; Park, J-H; Balicas, L; Lonzarich, G G; Balakrishnan, G; Sebastian, Suchitra E

    2015-07-17

    Insulators occur in more than one guise; a recent finding was a class of topological insulators, which host a conducting surface juxtaposed with an insulating bulk. Here, we report the observation of an unusual insulating state with an electrically insulating bulk that simultaneously yields bulk quantum oscillations with characteristics of an unconventional Fermi liquid. We present quantum oscillation measurements of magnetic torque in high-purity single crystals of the Kondo insulator SmB6, which reveal quantum oscillation frequencies characteristic of a large three-dimensional conduction electron Fermi surface similar to the metallic rare earth hexaborides such as PrB6 and LaB6. The quantum oscillation amplitude strongly increases at low temperatures, appearing strikingly at variance with conventional metallic behavior. PMID:26138105

  10. Unoccupied electronic states in adsorbate systems

    NASA Astrophysics Data System (ADS)

    Bertel, E.

    1991-11-01

    Experimental work on unoccupied electronic states in adsorbate systems on metallic substrates is reviewed with emphasis on recent developments. The first part is devoted to molecular adsorbates. Weakly chemisorbed hydrocarbons are briefly discussed. An exhaustive inverse photoemission (IPE) study of the CO bond to the transition metals Ni, Pb, and Pt is presented. Adsorbed NO is taken as an example to demonstrate the persisting discrepancies in the interpretation of IPE spectra. Atomic adsorbates are discussed in the second part. The quantum well state model is applied to interpret the surface states in reconstructing and non-reconstructing adsorption systems of alkali metals and hydrogen. A recent controversy on the unoccupied electronic states of the Cu(110)/O p(2×1) surface is critically reviewed. The quantum well state model is then compared to tight binding and local-density-functional calculations of the unoccupied bands and the deficiencies of the various approaches are pointed out. Finally, the relation between the surface state model and more chemically oriented models of surface bonding is briefly discussed.

  11. 77 FR 39206 - Public Hearing on Proposed Rule for Heavy Vehicle Electronic Stability Control Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-02

    ... No. 136, Electronic Stability Control Systems for Heavy Vehicles (77 FR 30766). The standard would require truck tractors, and certain large buses with a gross vehicle weight rating of greater than 11,793... (ESC) systems on truck tractors and large buses. NHTSA is announcing a public hearing to provide...

  12. Electronic Cigarette Use among College Students: Links to Gender, Race/Ethnicity, Smoking, and Heavy Drinking

    ERIC Educational Resources Information Center

    Littlefield, Andrew K.; Gottlieb, Joshua C.; Cohen, Lee M.; Trotter, David R. M.

    2015-01-01

    Objective: Electronic cigarette (e-cigarette) use continues to rise, and current data regarding use of e-cigarettes among college students are needed. The purpose of this study was to examine e-cigarette use and the relation of such use with gender, race/ethnicity, traditional tobacco use, and heavy drinking. Participants and Methods: A sample of…

  13. A modular solid state detector for measuring high energy heavy ion fragmentation near the beam axis

    NASA Technical Reports Server (NTRS)

    Zeitlin, C. J.; Frankel, K. A.; Gong, W.; Heilbronn, L.; Lampo, E. J.; Leres, R.; Miller, J.; Schimmerling, W.

    1994-01-01

    A multi-element solid state detector has been designed to measure fluences of fragments produced near the beam axis by high energy heavy ion beams in thick targets. The detector is compact and modular, so as to be readily reconfigured according to the range of fragment charges and energies to be measured. Preamplifier gain settings and detector calibrations are adjustable remotely under computer control. We describe the central detector, its associated detectors and electronics, triggering scheme, data acquisition and particle identification techniques, illustrated by data taken with 600 MeV/u 56Fe beams and thick polyethylene targets at the LBL Bevalac. The applications of this work to space radiation protection are discussed.

  14. The relativistic polarization propagator for the calculation of electronic excitations in heavy systems

    SciTech Connect

    Pernpointner, Markus

    2014-02-28

    In this work, we present a new four-component implementation of the polarization propagator for accurate calculations of excited states in heavy systems. Differences to existing nonrelativistic realizations are detailed and the energetically lowest final states of the ns{sup 2}np{sup 6} → ns{sup 2}np{sup 5}(n + 1)s{sup 1} and ns{sup 2}np{sup 6} → ns{sup 2}np{sup 5}(n + 1)p{sup 1} transitions in noble gases are calculated and compared with experimental data. Already for the light atoms Ne and Ar spin-orbit coupling leads to noticeable zero field splitting that gradually increases in the heavier homologues and eventually invalidates the LS-based description of singlet and triplet excited states. For all four noble gases Ne through Xe, we observe a very good agreement with experimental transition energies in the considered energetic range where the extended version of the propagator implementation in general yields better excitation energy differences than the strict variant. In the extended version, off-diagonal first-order contributions in the two-particle-two-hole block are included that are not present in the strict variant. In case of Kr and Xe, nonrelativistic approaches already exhibit unacceptable deviations in the reproduction of transition energies and the spectral structure. The obtained excited final states are analyzed in terms of atomic contributions to the donor and acceptor orbitals constituting the corresponding wave functions. The relativistic polarization propagator provides a consistent description of electron correlation and relativistic effects especially relevant for the heavier systems where these two contributions are no longer separable.

  15. ECR (Electron Cyclotron Resonance) source for the HHIRF (Holifield Heavy Ion Research Facility) tandem accelerator

    SciTech Connect

    Olsen, D.K.; Alton, G.D.; Dowling, D.T.; Haynes, D.L.; Jones, C.M.; Juras, R.C.; Lane, S.N.; Meigs, M.J.; Mills, G.D.; Mosko, S.W.; Tatum, B.A.

    1990-01-01

    Electron Cyclotron Resonance, ECR, ion source technology has developed rapidly since the original pioneering work of R. Geller and his group at Grenoble in the early 1970s. These ion sources are capable of producing intense beams of highly charged positive ions and are used extensively for cyclotron injection, linac injection, and atomic physics research. In this paper, the advantages of using an ECR heavy-ion source in the terminal of the Holifield Heavy Ion Research Facility (HHIRF) 25-MV tandem accelerator is discussed. A possible ECR system for installation in the HHIRF tandem terminal is described.

  16. Visualizing Heavy Fermion Formation and their Unconventional Superconductivity in f-Electron Materials

    NASA Astrophysics Data System (ADS)

    Aynajian, Pegor; da Silva Neto, Eduardo H.; Zhou, Brian B.; Misra, Shashank; Baumbach, Ryan E.; Fisk, Zachary; Mydosh, John; Thompson, Joe D.; Bauer, Eric D.; Yazdani, Ali

    2014-06-01

    In solids containing elements with f-orbitals, the interaction between f-electron spins and those of itinerant electrons leads to the development of low-energy fermionic excitations with a heavy effective mass. These excitations are fundamental to the appearance of unconventional superconductivity observed in actinide- and lanthanide-based compounds. We use spectroscopic mapping with the scanning tunneling microscope to detect the emergence of heavy excitations with lowering of temperature in Ce- and U-based heavy fermion compounds. We demonstrate the sensitivity of the tunneling process to the composite nature of these heavy quasiparticles, which arises from quantum entanglement of itinerant conduction and f-electrons. Scattering and interference of the composite quasiparticles is used in the Ce-based compounds to resolve their energy-momentum structure and to extract their mass enhancement, which develops with decreasing temperature. Finally, by extending these techniques to much lower temperatures, we investigate how superconductivity, with a nodal d-wave character, develops within a strongly correlated band of composite excitations.

  17. An all permanent magnet electron cyclotron resonance ion source for heavy ion therapy

    SciTech Connect

    Cao, Yun Li, Jia Qing; Sun, Liang Ting; Zhang, Xue Zhen; Feng, Yu Cheng; Wang, Hui; Ma, Bao Hua; Li, Xi Xia

    2014-02-15

    A high charge state all permanent Electron Cyclotron Resonance ion source, Lanzhou All Permanent ECR ion source no. 3-LAPECR3, has been successfully built at IMP in 2012, which will serve as the ion injector of the Heavy Ion Medical Machine (HIMM) project. As a commercial device, LAPECR3 features a compact structure, small size, and low cost. According to HIMM scenario more than 100 eμA of C{sup 5+} ion beam should be extracted from the ion source, and the beam emittance better than 75 π*mm*mrad. In recent commissioning, about 120 eμA of C{sup 5+} ion beam was got when work gas was CH{sub 4} while about 262 eμA of C{sup 5+} ion beam was obtained when work gas was C{sub 2}H{sub 2} gas. The design and construction of the ion source and its low-energy transportation beam line, and the preliminary commissioning results will be presented in detail in this paper.

  18. Pair production and electron capture in relativistic heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Lee, R. J.; Mullan, J. V.; McCann, J. F.; Crothers, D. S.

    2001-06-01

    Results are presented for simulations of electron-positron pair production in relativistic heavy-ion collisions leading to electron capture and positron ejection. We apply a two-center relativistic continuum distorted-wave model to represent the electron or positron dynamics during the collision process. The results are compared with experimental cross-section data for La57+ and Au79+ impact on gold, silver, and copper targets. The theory is in good agreement with experiment for La57+ impact, verifying the result that the process increases in importance with both collision energy and target atomic number, and improves upon previous simulations of this process.

  19. Effect of electron-phonon interaction on resistivity of some heavy fermion (HF) systems

    SciTech Connect

    Sahoo, J.; Shadangi, N.; Nayak, P.

    2014-04-24

    Here, we have analyzed the electron-phonon interaction in the Periodic Anderson Model (PAM) to describe the temperature dependence of resistivity in some heavy fermion (HF) systems for finite wave vector (q) and for finite temperature (T). Since the resistivity is related to the imaginary part of the electron self energy, the expression for the same is evaluated through double time temperature dependant Green function technique of the Zubarev type. The effect of different system parameters namely the position of 4f level, E{sub 0} and the electron - phonon coupling strengths on resistivity have been studied. The results obtained give satisfactory explanations to the experimental observations.

  20. Initial Experimental Studies of Electron Accumulation in a Heavy Ion Beam

    SciTech Connect

    Molvik, A W; Baca, D; Bieniosek, F M; Cohen, R H; Friedman, A; Furman, M A; Lee, E P; Lund, S M; Prost, L; Sakumi, A; Seidl, P A; Vay, J L

    2003-05-01

    Accelerators for heavy-ion inertial fusion energy (HIF) have an economic incentive to fit beam tubes tightly to beams, putting them at risk from electron clouds produced by emission of electrons and gas from walls. Theory and PIC simulations suggest that the electrons will be radially trapped in the {approx}>1 kV ion-beam potential. We are beginning studies on the High-Current Experiment (HCX) with unique capabilities to characterize electron production and trapping, the effects on ion beams, and mitigation techniques. We are measuring the flux of electrons and gas evolved from a target, whose angle to the beam can be varied between 78 and 88 degrees from normal incidence. Quadrupole magnets are operating with a variety of internal charged particle diagnostics to measure the beam halo loss, net charge, electron ionization rate, and gas density.

  1. Pollution distribution of heavy metals in surface soil at an informal electronic-waste recycling site.

    PubMed

    Fujimori, Takashi; Takigami, Hidetaka

    2014-02-01

    We studied distribution of heavy metals [lead (Pb), copper (Cu) and zinc (Zn)] in surface soil at an electronic-waste (e-waste) recycling workshop near Metro Manila in the Philippines to evaluate the pollution size (spot size, small area or the entire workshop), as well as to assess heavy metal transport into the surrounding soil environment. On-site length-of-stride-scale (~70 cm) measurements were performed at each surface soil point using field-portable X-ray fluorescence (FP-XRF). The surface soil at the e-waste recycling workshop was polluted with Cu, Zn and Pb, which were distributed discretely in surface soil. The site was divided into five areas based on the distance from an entrance gate (y-axis) of the e-waste recycling workshop. The three heavy metals showed similar concentration gradients in the y-axis direction. Zn, Pb and Cu concentrations were estimated to decrease to half of their maximum concentrations at ~3, 7 and 7 m from the pollution spot, respectively, inside the informal e-waste recycling workshop. Distance from an entrance may play an important role in heavy metal transport at the soil surface. Using on-site FP-XRF, we evaluated the metal ratio to characterise pollution features of the solid surface. Variability analysis of heavy metals revealed vanishing surficial autocorrelation over metre ranges. Also, the possibility of concentration prediction at unmeasured points using geostatistical kriging was evaluated, and heavy metals had a relative "small" pollution scales and remained inside the original workshop compared with toxic organohalogen compounds. Thus, exposure to heavy metals may directly influence the health of e-waste workers at the original site rather than the surrounding habitat and environmental media. PMID:23645478

  2. Multiplet splitting for the XPS of heavy elements: Dependence on oxidation state

    NASA Astrophysics Data System (ADS)

    Bagus, Paul S.; Nelin, Connie J.; Al-Salik, Yahya; Ilton, Eugene S.; Idriss, Hicham

    2016-01-01

    Multiplet splittings in X-ray Photo-electron Spectroscopy, XPS, are a means of distinguishing different open shell occupations, or different oxidation states, in a material being studied. Indeed, especially for 3d transition metal complexes, they have provided fingerprints of the metal oxidation state. The present work provides theoretical and experimental evidence that it may also be possible to use multiplets to characterize the oxidation state of heavy metal, lanthanide and actinide, cations in complexes. However, it is important to make a proper choice of the XPS region to study in order to obtain large multiplet splittings. We identify a low binding energy, BE, peak that had been observed for Ce(III) in CeOx as a high spin coupled multiplet. Furthermore, we show that a low BE feature with reasonable intensity is characteristic of other XPS regions and of other metals. This feature arises from a high spin multiplet and serves as a fingerprint to distinguish closed shell from open shell cations. Evidence is presented that it may also be possible to distinguish different open shell occupations.

  3. Time-resolved electron kinetics in swift heavy ion irradiated solids

    NASA Astrophysics Data System (ADS)

    Medvedev, N. A.; Rymzhanov, R. A.; Volkov, A. E.

    2015-09-01

    The event-by-event Monte Carlo model, TREKIS, was developed to describe the excitation of the electron subsystems of various solids by a penetrating swift heavy ion (SHI), the spatial spreading of generated fast electrons, and secondary electron and hole cascades. Complex dielectric function formalism is used to obtain relevant cross sections. This allows the recognition of fundamental effects resulting from the collective response of the electron subsystem of a target for excitation that is not possible within the binary collision approximation of these cross sections, e.g. the differences in the electronic stopping of an ion and in the electron mean free paths for different structures (phases) of a material. A systematic study performed with this model for different materials (insulators, semiconductors and metals) revealed effects which may be important for an ion track: e.g. the appearance of a second front of excess electronic energy propagation outwards from the track core following the primary front of spreading of generated electrons. We also analyze how the initial ballistic spatial spreading of fast electrons generated in a track turns to the diffusion ~10 fs after ion passage. Detailed time-resolved simulations of electronic subsystem kinetics helped in understanding the reasons behind enhanced silicon resistance to SHI irradiation in contrast to easily produced damage in this material by femtosecond laser pulses. We demonstrate that the fast spreading of excited electrons from the track core on a sub-100 fs timescale prevents the Si lattice from nonthermal melting in a relaxing SHI track.

  4. One-quasiparticle states in odd-Z heavy nuclei

    SciTech Connect

    Adamian, G. G.; Antonenko, N. V.; Kuklin, S. N.; Scheid, W.

    2010-11-15

    The isotopic dependencies of one-quasiparticle states in Es and Md are treated. In {sup 253,255}Lr, the energies of the lowest one-quasiproton states are calculated. The one-quasiparticle isomer states are revealed in the nuclei of an {alpha}-decay chain starting from {sup 269}Rg. The {alpha} decays from some isomer states are predicted. The population of isomer states in the complete fusion reactions is discussed.

  5. Electronic Tongue-FIA system for the Monitoring of Heavy Metal Biosorption Processes

    NASA Astrophysics Data System (ADS)

    Wilson, D.; Florido, A.; Valderrama, C.; de Labastida, M. Fernández; Alegret, S.; del Valle, M.

    2011-09-01

    An automated flow injection potentiometric (FIP) system with electronic tongue detection (ET) was used for the monitoring of biosorption processes of heavy metals on waste biomaterial. Grape stalk wastes were used as biosorbent to remove Cu2+ ions in a fixed-bed column setup. For the monitoring, the used ET employed a sensor array formed by Cu2+ and Ca2+ selective electrodes and two generic heavy-metal electrodes. The subsequent cross-response obtained was processed by a multilayer artificial neural network (ANN) model in order to resolve the concentrations of the monitored species. The coupling of the electronic tongue with the automation features of the flow-injection system (ET-FIP) allowed us to accurately characterize the biosorption process, through obtaining its breakthrough curves. In parallel, fractions of the extract solution were analyzed by atomic absorption spectroscopy in order to validate the results obtained with the reported methodology.

  6. Potential for detection of microorganisms and heavy metals in potable water using electronic nose technology.

    PubMed

    Canhoto, Olinda F; Magan, Naresh

    2003-05-01

    Studies have been carried out to determine the potential for the detection of different microbial species (Enterobacter aerogenes, Escherichia coli, Pseudomonas aeruginosa), alone and in the presence of low concentrations of different heavy metals (As, Cd, Pb and Zn) in bottled, reverse osmosis (RO) and tap water, using an electronic nose. Studies show that it is possible to discriminate control water samples from water contaminated with 0.5 ppm of a mixture of metals. The presence of heavy metals may modify the activity of microorganisms and thus the volatile production patterns. Bacterial species at 10(2)-10(4) colony forming units (CFUs) ml(-1) could be detected after 24 h of incubation. Work is in progress to identify the limits of detection for a range of other microorganisms, including, fungi and cyanobacteria, and chlorinated phenols using electronic nose technology. PMID:12706588

  7. The impacts of electronic state hybridization on the binding energy of single phosphorus donor electrons in extremely downscaled silicon nanostructures

    SciTech Connect

    The Anh, Le Manoharan, Muruganathan; Moraru, Daniel; Tabe, Michiharu; Mizuta, Hiroshi

    2014-08-14

    We present the density functional theory calculations of the binding energy of the Phosphorus (P) donor electrons in extremely downscaled single P-doped Silicon (Si) nanorods. In past studies, the binding energy of donor electrons was evaluated for the Si nanostructures as the difference between the ionization energy for the single P-doped Si nanostructures and the electron affinity for the un-doped Si nanostructures. This definition does not take into account the strong interaction of donor electron states and Si electron states explicitly at the conductive states and results in a monotonous increase in the binding energy by reducing the nanostructure's dimensions. In this paper, we introduce a new approach to evaluate the binding energy of donor electrons by combining the projected density of states (PDOS) analysis and three-dimensional analysis of associated electron wavefunctions. This enables us to clarify a gradual change of the spatial distribution of the 3D electron wavefunctions (3DWFs) from the donor electron ground state, which is fully localized around the P donor site to the first conductive state, which spreads over the outer Si nanorods contributing to current conduction. We found that the energy of the first conductive state is capped near the top of the atomistic effective potential at the donor site with respect to the surrounding Si atoms in nanorods smaller than about 27 a{sub 0}. This results in the binding energy of approximately 1.5 eV, which is virtually independent on the nanorod's dimensions. This fact signifies a good tolerance of the binding energy, which governs the operating temperature of the single dopant-based transistors in practice. We also conducted the computationally heavy transmission calculations of the single P-doped Si nanorods connected to the source and drain electrodes. The calculated transmission spectra are discussed in comparison with the atomistic effective potential distributions and the PDOS-3DWFs method.

  8. The impacts of electronic state hybridization on the binding energy of single phosphorus donor electrons in extremely downscaled silicon nanostructures

    NASA Astrophysics Data System (ADS)

    The Anh, Le; Moraru, Daniel; Manoharan, Muruganathan; Tabe, Michiharu; Mizuta, Hiroshi

    2014-08-01

    We present the density functional theory calculations of the binding energy of the Phosphorus (P) donor electrons in extremely downscaled single P-doped Silicon (Si) nanorods. In past studies, the binding energy of donor electrons was evaluated for the Si nanostructures as the difference between the ionization energy for the single P-doped Si nanostructures and the electron affinity for the un-doped Si nanostructures. This definition does not take into account the strong interaction of donor electron states and Si electron states explicitly at the conductive states and results in a monotonous increase in the binding energy by reducing the nanostructure's dimensions. In this paper, we introduce a new approach to evaluate the binding energy of donor electrons by combining the projected density of states (PDOS) analysis and three-dimensional analysis of associated electron wavefunctions. This enables us to clarify a gradual change of the spatial distribution of the 3D electron wavefunctions (3DWFs) from the donor electron ground state, which is fully localized around the P donor site to the first conductive state, which spreads over the outer Si nanorods contributing to current conduction. We found that the energy of the first conductive state is capped near the top of the atomistic effective potential at the donor site with respect to the surrounding Si atoms in nanorods smaller than about 27 a0. This results in the binding energy of approximately 1.5 eV, which is virtually independent on the nanorod's dimensions. This fact signifies a good tolerance of the binding energy, which governs the operating temperature of the single dopant-based transistors in practice. We also conducted the computationally heavy transmission calculations of the single P-doped Si nanorods connected to the source and drain electrodes. The calculated transmission spectra are discussed in comparison with the atomistic effective potential distributions and the PDOS-3DWFs method.

  9. End-point Region of the Electron Spectrum in Inclusive Semileptonic Heavy Quark Decay

    SciTech Connect

    Isgur, Nathan

    1992-01-01

    I examine the relationship between the inclusive and sum-over-exclusive-resonances pictures for the electron spectrum of semileptonic heavy quark decay. The analysis shown to that obtained from a free-quark-decay-type model with an endpoint adjusted to the physical endpoint. This conclusion removes the need for nonresonant contributions in the endpoint region and is consistent with arguments that free-quark-decay-type models are, in principle,

  10. {open_quotes}Heavy light bullets{close_quotes} in electron-positron plasma

    SciTech Connect

    Berezhiani, V.I.; Mahajan, S.M.

    1995-03-01

    The nonlinear propagation of circularly polarized electromagnetic waves with relativistically strong amplitudes in an unmagnetized hot electron-positron plasma with a small fraction of ions is investigated. The possibility of finding localized solutions in such a plasma is explored. It is shown that these plasmas support the propagation of {open_quotes}heavy light bullets{close_quotes}; nondiffracting and nondispersive electromagnetic (EM) pulses with large density bunching.

  11. Manifestation of cluster effects in collective octupole and superdeformed states of heavy nuclei.

    NASA Astrophysics Data System (ADS)

    Shneidman, T. M.; Adamian, G. G.; Antonenko, N. V.; Jolos, R. V.

    2016-06-01

    The effects of reflection-asymmetric deformation on the properties of the low-lying negative-parity collective states and superdeformed states of heavy nuclei are analyzed basing on dinuclear model. The results of consideration of the alternating parity bands in actinides and the superdeformed bands in 60Zn, Pb and Hg isotopes are discussed.

  12. A small 1 MeV electron accelerator for measuring heavy metal concentrations in smokestack gases

    NASA Astrophysics Data System (ADS)

    Reppond, A.; Redden, D. P.; Meitzler, C. R.; Swenson, D. A.

    1997-05-01

    A low-current electron beam may be used as a diagnostic tool to measure the concentrations of heavy metals (Cd, Pb, Hg) present in the flue gas particulates produced by smelters or cement kilns. A small electron accelerator is being constructed as part of a prototype emissions monitoring system. The electron beam energy has a design energy of 1 MeV, a peak current of 5 mA, and a duty factor of 0.1 percent. In this paper, we discuss the results of a set of EGS4 calculations used to model the transport properties of a 1 MeV electron beam passing through a thin vacuum window and the flue gas. Since the accelerator will be mounted in a harsh environment, we have investigated the effects of temperature variations on the linac structure and RF power source. The present status of the accelerator construction project is presented.

  13. The Electron Shell and Alpha Decay in Super-Heavy Nuclei

    NASA Astrophysics Data System (ADS)

    Igashov, S. Yu.; Tchuvil'Sky, Yu. M.

    2015-11-01

    The influence of the electron shell on the characteristics of the alpha decay of the 294118 isotope, as an example of a super-heavy atom, is studied theoretically. The calculation is based on direct solution of the Schrödinger equation. The rigorous quantum-mechanical approach being developed makes possible the outer boundary condition of the alpha-particle diverging wave to be taken into account properly. The effect under discussion depends on the behavior of the function of electron density both in the classically-forbidden and the classically-allowed areas of alpha-particle motion. A principally new effect - increasing of the decay rate originated by the part of electron shell located in the classically-allowed area - is revealed in the chosen example. The influence of relativistic properties of inner electrons, scenario of penetration of the alpha-particle through the atomic shell and finite size of nucleus are also studied.

  14. On the Electronically Excited States of Uracil

    SciTech Connect

    Epifanovsky, Evgeny; Kowalski, Karol; Fan, Peng-Dong; Valiev, Marat; Matsika, Spiridoula; Krylov, Anna

    2008-10-09

    Vertical excitation energies in uracil in the gas phase and in water solution are investigated by the equation-of-motion coupled-cluster and multi-reference configuration interaction methods. Basis set effects are found to be important for converged results. The analysis of electronic wave functions reveals that the lowest singlet states are predominantly of a singly excited character and are therefore well described by single-reference equation-of-motion methods augmented by a perturbative triples correction to account for dynamical correlation. Our best estimates for the vertical excitation energies for the lowest singlet n and are 5.0±0.1 eV and 5.3±0.1 eV, respectively. The solvent effects for these states are estimated to be +0.5 eV and ±0.1 eV, respectively. We attribute the difference between the computed vertical excitations and the maximum of the experimental absorption to strong vibronic interaction between the lowest A00 and A0 states leading to intensity borrowing by the forbidden transition.

  15. Photoelectron Spectroscopy and Electronic Structure of Heavy GroupIV-VI Diatomics

    SciTech Connect

    Wang, L.-S.; Niu, B.; Lee, Yuan T.; Shirley, D.A.; Balasubramanian, K.

    1989-09-01

    Vibrationally-resolved HeI (584{angstrom}) photoelectron spectra of the heavy group IV-VI diatomics SnSe, SnTe, PbSe, and PbTe were obtained with a new high temperature molecular beam source. Ionization potentials and spectroscopic constants are reported for all the ionic states observed. Relativistic complete active space MCSCF followed by multireference singles + doubles relativistic CI calculations which included up to 200,000 configurations were made on both the neutral diatomics and their positive ions. Ionization potentials and spectroscopic constants were calculated and were in good agreement with the experimentally-measured values. Relativistic CI potential energy curves were calculated for all the neutral ground states and the ionic states involved. Relativistic effects were shown to play an important role in these heavy diatomics. The {sup 2}{Sigma}{sub 1/2}{sup +} and {sup 2}{Pi}{sub 1/2} states for all four molecular ions showed avoided curve crossings, which resulted in pronounced shoulders in the {Omega} = 1/2 potential energy curves of PbTe{sup +}. Experimentally, autoionization transitions were also observed for the PbTe{sup +} spectrum. The importance of the relativistic effect and chemical bonding in the heavy diatomics are discussed.

  16. Magnetism, f-electron localization and superconductivity in 122-type heavy-fermion metals.

    PubMed

    Steglich, F; Arndt, J; Stockert, O; Friedemann, S; Brando, M; Klingner, C; Krellner, C; Geibel, C; Wirth, S; Kirchner, S; Si, Q

    2012-07-25

    Both CeCu2Si2 and YbRh2Si2 crystallize in the tetragonal ThCr2Si2 crystal structure. Recent neutron-scattering results on normal-state CeCu2Si2 reveal a slowing down of the quasielastic response which complies with the scaling expected for a quantum critical point (QCP) of itinerant, i.e., three-dimensional spin-density-wave (SDW), type. This interpretation is in full agreement with the non-Fermi-liquid behavior observed in transport and thermodynamic measurements. The momentum dependence of the magnetic excitation spectrum reveals two branches of an overdamped dispersive mode whose coupling to the heavy charge carriers is strongly retarded. These overdamped spin fluctuations are considered to be the driving force for superconductivity in CeCu2Si2 (Tc = 600 mK). The weak antiferromagnet YbRh2Si2 (TN = 70 mK) exhibits a magnetic-field-induced QCP at BN = 0.06 T (B⊥c). There is no indication of superconductivity down to T = 10 mK. The magnetic QCP appears to concur with a breakdown of the Kondo effect. Doping-induced variations of the average unit-cell volume result in a detachment of the magnetic and electronic instabilities. A comparison of the properties of these isostructural compounds suggests that 3D SDW QCPs are favorable for unconventional superconductivity. The question whether a Kondo-breakdown QCP may also give rise to superconductivity, however, remains to be clarified. PMID:22773300

  17. Magnetism, f-electron localization and superconductivity in 122-type heavy-fermion metals

    NASA Astrophysics Data System (ADS)

    Steglich, F.; Arndt, J.; Stockert, O.; Friedemann, S.; Brando, M.; Klingner, C.; Krellner, C.; Geibel, C.; Wirth, S.; Kirchner, S.; Si, Q.

    2012-07-01

    Both CeCu2Si2 and YbRh2Si2 crystallize in the tetragonal ThCr2Si2 crystal structure. Recent neutron-scattering results on normal-state CeCu2Si2 reveal a slowing down of the quasielastic response which complies with the scaling expected for a quantum critical point (QCP) of itinerant, i.e., three-dimensional spin-density-wave (SDW), type. This interpretation is in full agreement with the non-Fermi-liquid behavior observed in transport and thermodynamic measurements. The momentum dependence of the magnetic excitation spectrum reveals two branches of an overdamped dispersive mode whose coupling to the heavy charge carriers is strongly retarded. These overdamped spin fluctuations are considered to be the driving force for superconductivity in CeCu2Si2 (Tc = 600 mK). The weak antiferromagnet YbRh2Si2 (TN = 70 mK) exhibits a magnetic-field-induced QCP at BN = 0.06 T (B⊥c). There is no indication of superconductivity down to T = 10 mK. The magnetic QCP appears to concur with a breakdown of the Kondo effect. Doping-induced variations of the average unit-cell volume result in a detachment of the magnetic and electronic instabilities. A comparison of the properties of these isostructural compounds suggests that 3D SDW QCPs are favorable for unconventional superconductivity. The question whether a Kondo-breakdown QCP may also give rise to superconductivity, however, remains to be clarified.

  18. Remaking Teacher Evaluation: A Heavy Lift for State Education Policymakers

    ERIC Educational Resources Information Center

    McGuinn, Patrick

    2015-01-01

    The "Race to the Top" competitive grant program initiated a wave of teacher evaluation reform, which scholars and policymakers have long identified as critical to improving teacher quality and student performance. State boards of education (SBEs) and state education agencies (SEAs) took different approaches to these reforms, and as a…

  19. Electronic and atomic kinetics in solids irradiated with free-electron lasers or swift-heavy ions

    NASA Astrophysics Data System (ADS)

    Medvedev, N.; Volkov, A. E.; Ziaja, B.

    2015-12-01

    In this brief review we discuss the transient processes in solids under irradiation with femtosecond X-ray free-electron-laser (FEL) pulses and swift-heavy ions (SHI). Both kinds of irradiation produce highly excited electrons in a target on extremely short timescales. Transfer of the excess electronic energy into the lattice may lead to observable target modifications such as phase transitions and damage formation. Transient kinetics of material excitation and relaxation under FEL or SHI irradiation are comparatively discussed. The same origin for the electronic and atomic relaxation in both cases is demonstrated. Differences in these kinetics introduced by the geometrical effects (μm-size of a laser spot vs nm-size of an ion track) and initial irradiation (photoabsorption vs an ion impact) are analyzed. The basic mechanisms of electron transport and electron-lattice coupling are addressed. Appropriate models and their limitations are presented. Possibilities of thermal and nonthermal melting of materials under FEL and SHI irradiation are discussed.

  20. Electronically shielded solid state charged particle detector

    DOEpatents

    Balmer, D.K.; Haverty, T.W.; Nordin, C.W.; Tyree, W.H.

    1996-08-20

    An electronically shielded solid state charged particle detector system having enhanced radio frequency interference immunity includes a detector housing with a detector entrance opening for receiving the charged particles. A charged particle detector having an active surface is disposed within the housing. The active surface faces toward the detector entrance opening for providing electrical signals representative of the received charged particles when the received charged particles are applied to the active surface. A conductive layer is disposed upon the active surface. In a preferred embodiment, a nonconductive layer is disposed between the conductive layer and the active surface. The conductive layer is electrically coupled to the detector housing to provide a substantially continuous conductive electrical shield surrounding the active surface. The inner surface of the detector housing is supplemented with a radio frequency absorbing material such as ferrite. 1 fig.

  1. Electronically shielded solid state charged particle detector

    SciTech Connect

    Balmer, D.K.; Haverty, T.W.; Nordin, C.W.; Tyree, W.H.

    1995-12-31

    An electronically shielded solid state charged particle detector system having enhanced radio frequency interference immunity includes a detector housing with a detector entrance opening for receiving the charged particles. A charged particle detector having an active surface is disposed within the housing. The active surface faces toward the detector entrance opening for providing electrical signals representative of the received charged particles when the received charged particles are applied to the active surface. A conductive layer is disposed upon the active surface. In a preferred embodiment, a nonconductive layer is disposed between the conductive layer and the active surface. The conductive layer is electrically coupled to the detector housing to provide a substantially continuous conductive electrical shield surrounding the active surface. The inner surface of the detector housing is supplemented with a radio frequency absorbing material such as ferrite.

  2. Electronically shielded solid state charged particle detector

    DOEpatents

    Balmer, David K.; Haverty, Thomas W.; Nordin, Carl W.; Tyree, William H.

    1996-08-20

    An electronically shielded solid state charged particle detector system having enhanced radio frequency interference immunity includes a detector housing with a detector entrance opening for receiving the charged particles. A charged particle detector having an active surface is disposed within the housing. The active surface faces toward the detector entrance opening for providing electrical signals representative of the received charged particles when the received charged particles are applied to the active surface. A conductive layer is disposed upon the active surface. In a preferred embodiment, a nonconductive layer is disposed between the conductive layer and the active surface. The conductive layer is electrically coupled to the detector housing to provide a substantially continuous conductive electrical shield surrounding the active surface. The inner surface of the detector housing is supplemented with a radio frequency absorbing material such as ferrite.

  3. Self-consistent simulations of heavy-ion beams interacting with electron-clouds

    NASA Astrophysics Data System (ADS)

    Vay, J.-L.; Furman, M. A.; Seidl, P. A.; Cohen, R. H.; Friedman, A.; Grote, D. P.; Kireeff Covo, M.; Molvik, A. W.; Stoltz, P. H.; Veitzer, S.; Verboncoeur, J. P.

    2007-07-01

    Electron clouds and rising desorbed gas pressure limit the performance of many existing accelerators and, potentially, that of future accelerators including heavy-ion warm-dense matter and fusion drivers. For the latter, self-consistent simulation of the interaction of the heavy-ion beam(s) with the electron cloud is necessary. To this end, we have merged the two codes WARP (HIF accelerator code) and POSINST (high-energy e-cloud build-up code), and added modules for neutral gas molecule generation, gas ionization, and electron tracking algorithms in magnetic fields with large time steps. The new tool is being benchmarked against the High-Current Experiment (HCX) and good agreement has been achieved. The simulations have also aided diagnostic interpretation and have identified unanticipated physical processes. We present the "roadmap" describing the different modules and their interconnections, along with detailed comparisons with HCX experimental results, as well as a preliminary application to the modeling of electron clouds in the Large Hadron Collider.

  4. Effect on Electron Structure and Magneto-Optic Property of Heavy W-Doped Anatase TiO2.

    PubMed

    Hou, Qingyu; Zhao, Chunwang; Guo, Shaoqiang; Mao, Fei; Zhang, Yue

    2015-01-01

    The spin or nonspin state of electrons in W-doped anatase TiO2 is very difficult to judge experimentally because of characterization method limitations. Hence, the effect on the microscopic mechanism underlying the visible-light effect of W-doped anatase TiO2 through the consideration of electronic spin or no-spin states is still unknown. To solve this problem, we establish supercell models of W-doped anatase TiO2 at different concentrations, followed by geometry optimization and energy calculation based on the first-principle planewave norm conserving pseudo-potential method of the density functional theory. Calculation results showed that under the condition of nonspin the doping concentration of W becomes heavier, the formation energy becomes greater, and doping becomes more difficult. Meanwhile, the total energy increases, the covalent weakens and ionic bonds strengthens, the stability of the W-doped anatase TiO2 decreases, the band gap increases, and the blue-shift becomes more significant with the increase of W doping concentration. However, under the condition of spin, after the band gap correction by the GGA+U method, it is found that the semimetal diluted magnetic semiconductors can be formed by heavy W-doped anatase TiO2. Especially, a conduction electron polarizability of as high as near 100% has been found for the first time in high concentration W-doped anatase TiO2. It will be able to be a promising new type of dilute magnetic semiconductor. And the heavy W-doped anatase TiO2 make the band gap becomes narrower and absorption spectrum red-shift. PMID:25955308

  5. Effect on Electron Structure and Magneto-Optic Property of Heavy W-Doped Anatase TiO2

    PubMed Central

    Hou, Qingyu; Zhao, Chunwang; Guo, Shaoqiang; Mao, Fei; Zhang, Yue

    2015-01-01

    The spin or nonspin state of electrons in W-doped anatase TiO2 is very difficult to judge experimentally because of characterization method limitations. Hence, the effect on the microscopic mechanism underlying the visible-light effect of W-doped anatase TiO2 through the consideration of electronic spin or no-spin states is still unknown. To solve this problem, we establish supercell models of W-doped anatase TiO2 at different concentrations, followed by geometry optimization and energy calculation based on the first-principle planewave norm conserving pseudo-potential method of the density functional theory. Calculation results showed that under the condition of nonspin the doping concentration of W becomes heavier, the formation energy becomes greater, and doping becomes more difficult. Meanwhile, the total energy increases, the covalent weakens and ionic bonds strengthens, the stability of the W-doped anatase TiO2 decreases, the band gap increases, and the blue-shift becomes more significant with the increase of W doping concentration. However, under the condition of spin, after the band gap correction by the GGA+U method, it is found that the semimetal diluted magnetic semiconductors can be formed by heavy W-doped anatase TiO2. Especially, a conduction electron polarizability of as high as near 100% has been found for the first time in high concentration W-doped anatase TiO2. It will be able to be a promising new type of dilute magnetic semiconductor. And the heavy W-doped anatase TiO2 make the band gap becomes narrower and absorption spectrum red-shift. PMID:25955308

  6. The f-spin physics of rare-earth iron pnictides: influence of d-electron antiferromagnetic order on heavy fermion phase diagram

    SciTech Connect

    Zhu, Jian-xin; Dai, Jianhui; Si, Qimiao

    2009-01-01

    Some of the high {Tc} iron pnictides contain rare-earth elements, raising the question of how the existence and tunability of a d-electron antiferromagnetic order influences the heavy fermion behavior of the f-moments. With CeOFeP and CeOFeAs in mind as prototypes, we derive an extended Anderson lattice model appropriate for these quaternary systems. We show that the Kondo screening of the f-moments are efficiently suppressed by the d-electron ordering. We also argue that, inside the d-electron ordered state (as in CeOFeAs), the f-moments provide a rare realization of a quantum frustrated magnet with competing J{sub 1}-J{sub 2}-J{sub 3} interactions in an effective square lattice. Implications ofr the heavy fermion physics in broader contexts are also discussed.

  7. Electron emission from fast heavy ions associated with resonant coherent excitation

    NASA Astrophysics Data System (ADS)

    Suda, S.; Nakano, Y.; Metoki, K.; Azuma, T.; Takano, Y.; Hatakeyama, A.; Nakai, Y.; Komaki, K.; Takada, E.; Murakami, T.

    2011-06-01

    We observed convoy electrons emitted from 416 MeV/u He-like Ar16+ passing through a thin Si crystal under the condition of three-dimensional resonant coherent excitation (3D-RCE). The convoy electrons, which originate from electrons released from ions into the continuum by collisions with target atoms, emerged in the forward direction and formed a cusp-shaped peak in the energy distribution. We selectively controlled the population of the ground and excited states of ions traveling through the crystal by using 3D-RCE, where the 1s electron was excited to the 2p state by a periodic crystal field. Under the resonance condition, we found an enhancement of the convoy electrons with a narrowing in the energy distribution, which reflects the electron momentum distribution of the initial bound state of the excited ions.

  8. Low-lying electronic states of carotenoids.

    PubMed

    DeCoster, B; Christensen, R L; Gebhard, R; Lugtenburg, J; Farhoosh, R; Frank, H A

    1992-08-28

    Four all-trans carotenoids, spheroidene, 3,4-dihydrospheroidene, 3,4,5,6-tetrahydrospheroidene, and 3,4,7,8-tetrahydrospheroidene, have been purified using HPLC techniques and analyzed using absorption, fluorescence and fluorescence excitation spectroscopy of room temperature solutions. This series of molecules, for which the extent of pi-electron conjugation decreases from 10 to seven carbon-carbon double bonds, exhibits a systematic crossover from S2----S0 (1(1)Bu----1(1)Ag) to S1----S0 (2(1)Ag----1(1)Ag) emission with decreasing chain length. Extrapolation of the S1----S0 transition energies indicates that the 2(1)Ag states of longer carotenoids have considerably lower energies than previously thought. The energies of the S1 states of spheroidenes and other long carotenoids are correlated with the S1 energies of their chlorophyll partners in antenna complexes of photosynthetic systems. Implications for energy transfer in photosynthetic antenna are discussed. PMID:1510992

  9. Understanding the nuclear initial state with an electron ion collider

    NASA Astrophysics Data System (ADS)

    Toll, Tobias

    2013-09-01

    In these proceedings I describe how a future electron-ion collider will allow us to directly measure the initial spatial distribution of gluons in heavy ions, as well as its variance ("lumpiness") in exclusive diffraction. I show the feasibility of such a measurement by means of simulated data from the novel event generator Sartre.

  10. Measurement of electrons from heavy-flavor decays from p + p, d + Au , and Cu + Cu collisions in the PHENIX experiment

    NASA Astrophysics Data System (ADS)

    Lim, Sanghoon

    2014-11-01

    Charm and bottom quarks are formed predominantly by gluon fusion in the initial hard scatterings at RHIC, making them good probes of the full medium evolution. Previous measurements at RHIC have shown large suppression and azimuthal anisotropy of open heavy-flavor hadrons in Au + Au collisions at √{sNN} = 200 GeV. Explaining the simultaneously large suppression and flow of heavy quarks has been challenging. To further understand the heavy-flavor transport in the hot and dense medium, it is imperative to also measure cold nuclear matter effects which affect the initial distribution of heavy quarks as well as the system size dependence of the final state suppression. In this talk, new measurements by the PHENIX Collaboration of electrons from heavy-flavor decays in p + p, d + Au , and Cu + Cu collisions at √{sNN} = 200 GeV are presented. In particular, a surprising enhancement of intermediate transverse momentum heavy-flavor decay leptons in d + Au at mid and backward rapidity are also seen in mid-central Cu + Cu collisions. This enhancement is much larger than the expectation from anti-shadowing of the parton distributions and is theoretically unexplained.

  11. Nuclear Magnetic Resonance Studies of the Normal State of the Heavy Fermion System URANIUM-BERYLLIUM(13)

    NASA Astrophysics Data System (ADS)

    Lan, Kenneth Ming-Der

    ^9Be nuclear magnetic resonance measurements are reported for the normal state of the actinide intermetallic compound UBe_{13} . The motivation for this work was to examine the enhancement effect of the heavy fermions in this material in terms of their effect on the dynamic and static parts of the local magnetic field provided by the heavy fermions. The NMR experiments were done over a wide range of temperature and magnetic field. In the normal state of UBe_{13}, measurements in the temperature range extending from 0.8 K to room temperature were carried out, while a magnetic field of up to 70 kOe was applied. The measured ^9Be Knight shift in the normal state of UBe_{13 } is large, strongly temperature dependent and highly anisotropic. Above the characteristic temperature T* ~ 10 K, the Knight shift is linearly proportional to the static susceptibility. However, it deviates from this behavior at low temperature. The average isotropic Knight shifts for T < 10 K are approximately -0.08(1) % and 0.09(1) % for Be_{rm I} and Be_{rm II}, respectively. These results indicate an enhancement by a factor of 26 over what is found in pure Be metal. The ^9Be spin-lattice relaxation rate in UBe_{13} shows that the noise power of ^9Be local -field fluctuation due to the presence of heavy electrons is three orders of magnitude larger than the value observed in the corresponding non-5f intermetallic compound ThBe _{13}. This enhancement of the relaxation rate is associated with the formation of a narrow state near the Fermi energy that has a large component of f-electron density. The magnetic field dependence of ^9 Be spin-lattice relaxation rate was also measured in the superconducting state to understand the role of undetermined paramagnetic impurities in the heavy fermion system. The relaxation is through nuclear spin diffusion to the paramagnetic center. The observed field dependence at low fields may arise from diffusion-limited relaxation. At high magnetic fields the spin

  12. Possible Heavy Fermion State of the Caged Cubic Compound NdV2Al20

    NASA Astrophysics Data System (ADS)

    Namiki, Takahiro; Lei, Qiankun; Isikawa, Yosikazu; Nishimura, Katsuhiko

    2016-07-01

    The magnetic susceptibility M/H, the magnetization M, and the specific heat C were measured for the caged cubic compound NdV2Al20 single crystal at temperatures down to 0.5 K in magnetic fields H along the three principal crystallographic axes [001], [101], and [111]. The electrical resistivity ρ was measured in the temperature range of 1.9-300 K. A ferromagnetic phase transition was observed at a Curie temperature TC of 1.81 K. The easy direction of magnetization was the [001] direction at low fields, and changed to the [101] direction above 2 T. On cooling below 2 K at zero field, the specific heat divided by temperature, C/T, resulted in a large electronic specific heat coefficient γ of about 2 J/(K2 mol). A large C/T of more than 1 J/(K2 mol) remained at 9 T below 2 K. The temperature dependence of ρ showed the -ln T dependence at around 10 K. These behaviors possibly originate from a heavy fermion state.

  13. Synergy of Electronic Excitations and Elastic Collision Spikes in Sputtering of Heavy Metal Oxides

    SciTech Connect

    Schenkel, T.; Barnes, A.V.; Hamza, A.V.; Schneider, D.H.; Banks, J.C.; Doyle, B.L.

    1998-05-01

    The emission of secondary ions and neutrals from uranium oxide has been measured for impact of highly charged, heavy ions. Total ablation rates and secondary ion yields increase strongly with projectile charge. The dependencies on projectile charge (16{lt}q{lt}70) , impact energy (10 keV{lt}E{sub kin }{lt}1 MeV) , and projectile mass of secondary ion yields demonstrate the presence of an interaction regime where electronic excitation by charge neutralization and elastic collision spikes combine synergistically. {copyright} {ital 1998} {ital The American Physical Society}

  14. Electron-impact ionization of the K-shells of Heavy Atoms

    NASA Astrophysics Data System (ADS)

    Pindzola, M. S.

    2016-05-01

    Fully-relativistic subconfiguration-average distorted-wave (SCADW) calculations are made for the electron-impact ionization of the K-shells of heavy atoms. One set of calculations only include the two-body electrostatic interaction, while the other set includes the full two-body retarded electromagnetic interaction. The SCADW retarded electromagnetic calculations are found to be in good agreement with recent measurements made at the Institute for Physics at the University of Sao Paulo, Brazil for Au and Bi atoms. Calculations and measurements will also be presented for the K-shell ionization of the Ta atom. Work supported in part by Grants from NSF and DOE.

  15. Early stage of the electron kinetics in swift heavy ion tracks in dielectrics

    SciTech Connect

    Medvedev, N. A.; Rethfeld, B.; Volkov, A. E.; Shcheblanov, N. S.

    2010-09-15

    A Monte Carlo approach was applied for simulations of the early stage (first tens of femtosecond) of kinetics of the electronic subsystem of silica (SiO{sub 2}) in tracks of swift heavy ions (SHIs) decelerated in the electronic stopping regime. At the first step multiple ionizations of target atoms by a projectile (Ca{sup +19}, E=11.4 MeV/amu) were described that gave the initial spatial distributions of free electrons having different momenta as well as distributions of holes in different atomic shells. Spatial propagation of fast electrons results in secondary ionizations of target atoms as well as in energy transfer to the lattice at times much shorter than the times of atomic oscillations (phonons). The well detected front of excitation in the electronic and ionic subsystems is formed due to this propagation which cannot be described by models based on diffusion mechanisms (e.g., parabolic equations of heat diffusion). At times {approx}10 fs after the projectile passage, about {approx}0.1% of the energy is already transferred to the lattice. About 63% of the energy deposited by the ion is accumulated in holes at these times. Calculated distributions of these holes through the atomic shells are in excellent agreement with the spectroscopy experiments. Comparison with these experiments demonstrated also that relaxation of the electronic subsystem in SHI tracks in solids cannot be described adequately without taking into account intra-atomic and interatomic Auger (Knotek-Feibelman) processes.

  16. Developing an Accelerator Driven System (ADS) based on electron accelerators and heavy water

    NASA Astrophysics Data System (ADS)

    Feizi, H.; Ranjbar, A. H.

    2016-02-01

    An ADS based on electron accelerators has been developed specifically for energy generation and medical applications. Monte Carlo simulations have been performed using FLUKA code to design a hybrid electron target and the core components. The composition, geometry of conversion targets and the coolant system have been optimized for electron beam energies of 20 to 100 MeV . Furthermore, the photon and photoneutron energy spectra, distribution and energy deposition for various incoming electron beam powers have been studied. Light-heavy water of various mixtures have been used as heat removal for the targets, as γ-n converters and as neutron moderators. We have shown that an electron LINAC, as a neutron production driver for ADSs, is capable of producing a neutron output of > 3.5 × 1014 (n/s/mA). Accordingly, the feasibility of an electron-based ADS employing the designed features is promising for energy generation and high intense neutron production which have various applications such as medical therapies.

  17. Camelback-shaped band reconciles heavy-electron behavior with weak electronic Coulomb correlations in superconducting TlNi2Se2

    NASA Astrophysics Data System (ADS)

    Matt, Christian; Xu, Nan; van Roekeghem, A.; Biermann, S.; Richard, P.; Shi, X.; Wu, S.-F.; Liu, H. W.; Chen, D.; Qian, T.; Ding, H.; Wang, H.; Mao, Q.; Du, J.; Fang, M.; Plumb, N.; Radovic, M.; Mesot, J.; Shi, M.

    Combining photoemission spectroscopy, Raman spectroscopy, and first-principles calculations, we characterize superconducting TlNi2Se2 as a material with weak electronic Coulomb correlations leading to a bandwidth renormalization of 1.4. We identify a camelback-shaped band, whose energetic position strongly depends on the selenium height. While this feature is universal in transition metal pnictides, in TlNi2Se2 it lies in the immediate vicinity of the Fermi level, giving rise to a pronounced van Hove singularity (VHS). The resulting heavy band mass resolves the apparent puzzle of a large normal-state Sommerfeld coefficient in this weakly correlated compound. The correlation effect evolution in pnictides upon d-shell filling in the presence of significant Hund's exchange coupling will also be discussed.

  18. Constraints on the asymmetric equation of state from heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Yennello, Sherry; McIntosh, Alan; Heilborn, Lauren

    2016-05-01

    Nuclear matter is one of the most fascinating materials that exists.Therefore elucidating the equation-of-state of nuclear matter is a fundamentally interesting question. Additionally, the nuclear equationof-state has impacts on astrophysical observables. One important means of constraining the nuclear equation-of-state is through studying heavy-ion collisions. Nuclear material has two components - neutrons and protons - the ratio of which impacts the equation-of-state. Measurements of fragments emitted from reactions of nuclei with different ratios of neutrons and protons - and comparison to simulations based on various underlying interactions - have placed constraints on both the symmetric and asymmetric parts of the equation of state.

  19. Electron crystallography of the scrapie prion protein complexed with heavy metals

    PubMed Central

    Wille, Holger; Govaerts, Cédric; Borovinskiy, Alexander; Latawiec, Diane; Downing, Kenneth H.; Cohen, Fred E.; Prusiner, Stanley B.

    2012-01-01

    The insolubility of the disease-causing isoform of the prion protein (PrPSc) has prevented studies of its three-dimensional structure at atomic resolution. Electron crystallography of two-dimensional crystals of N-terminally truncated PrPSc (PrP 27–30) and a miniprion (PrPSc106) provided the first insights at intermediate resolution on the molecular architecture of the prion. Here, we report on the structure of PrP 27–30 and PrPSc106 negatively stained with heavy metals. The interactions of the heavy metals with the crystal lattice were governed by tertiary and quaternary structural elements of the protein as well as the charge and size of the heavy metal salts. Staining with molybdate anions revealed three prominent densities near the center of the trimer that forms the unit cell, coinciding with the location of the β-helix that was proposed for the structure of PrPSc. Differential staining also confirmed the location of the internal deletion of PrPSc106 at or near these densities. PMID:17935686

  20. Electron and Hole States in Low Dimensional Structures

    NASA Astrophysics Data System (ADS)

    Edwards, Gerard

    Available from UMI in association with The British Library. In this thesis results from microscopic calculations for the electron and hole states in low dimensional heterostructures are presented. The basis for the calculation is the local empirical pseudopotential technique which is used to generate the bulk semiconductor bandstructure. Then an S matrix approach, which is numerically stable, is employed to propagate the solution through the layered structure. The technique is essentially a scattering approach and hence is suitable to describe the experimental situation of finite samples. The fact that a finite system is treated allows the formalism to be naturally extended to include an external E field. The calculations that have been done are for the (001) growth direction. In chapter 1 the basic concepts of semiconductor physics relevant to the material of this thesis are introduced. In Chapter 2 the theoretical technique used in this thesis, for conduction band states, is reviewed and compared and contrasted with alternative methods. The emergence of miniband states and Stark ladders in coupled GaAs/AlAs quantum well structures are dealt with in chapter 3. In Chapter 4 the bound state problem, relevant to optical properties, of the energy versus k_parallel subband dispersion of a AlGaAs-GaAs-AlGaAs quantum well is examined. Chapter 5 contains the extension of the theoretical technique to incorporate the spin-orbit interaction so that heterostructure hole states can be tackled. The validity of the effective mass theory treatment of the semiconductor interface and the Luttinger model of the bulk valence band is questioned and the microscopic nature of the GaAs-AlAs interface scattering investigated. In chapter 6 hole states in GaAs/AlAs double barrier structures and coupled multiple quantum well (MQW) structures are calculated. The anomalous formation of contact interface states instead of heavy hole minibands is observed in MQW structures. In chapter 7 In

  1. An incompressible state of a photo-excited electron gas

    PubMed Central

    Chepelianskii, Alexei D.; Watanabe, Masamitsu; Nasyedkin, Kostyantyn; Kono, Kimitoshi; Konstantinov, Denis

    2015-01-01

    Two-dimensional electrons in a magnetic field can form new states of matter characterized by topological properties and strong electronic correlations as displayed in the integer and fractional quantum Hall states. In these states, the electron liquid displays several spectacular characteristics, which manifest themselves in transport experiments with the quantization of the Hall resistance and a vanishing longitudinal conductivity or in thermodynamic equilibrium when the electron fluid becomes incompressible. Several experiments have reported that dissipationless transport can be achieved even at weak, non-quantizing magnetic fields when the electrons absorb photons at specific energies related to their cyclotron frequency. Here we perform compressibility measurements on electrons on liquid helium demonstrating the formation of an incompressible electronic state under these resonant excitation conditions. This new state provides a striking example of irradiation-induced self-organization in a quantum system. PMID:26007282

  2. Cross section for production of low-energy electron-positron pairs by relativistic heavy ions

    NASA Technical Reports Server (NTRS)

    Eby, P. B.

    1991-01-01

    Starting with the lowest-order unscreened QED matrix element for electron-positron pair production by heavy charged particles, the paper calculates the cross section for this process differential in all independent variables and valid for all pair energies small compared to the incident particle energy. Integration over the possible emission angles of one of the pair members gives an expression that is valid for low-energy pairs that can be compared with previous work based on the Weizsaecker-Williams method. Integration over the possible angles of the other pair member then yields an expression identical to one derived by Racah. The high energy-transfer limit of the expression for the cross section integrated over electron and positron angles is found to be identical to that of Kelner in the unscreened case.

  3. The influence of the electronic specific heat on swift heavy ion irradiation simulations of silicon.

    PubMed

    Khara, Galvin S; Murphy, Samuel T; Daraszewicz, Szymon L; Duffy, Dorothy M

    2016-10-01

    The swift heavy ion (SHI) irradiation of materials is often modelled using the two-temperature model. While the model has been successful in describing SHI damage in metals, it fails to account for the presence of a bandgap in semiconductors and insulators. Here we explore the potential to overcome this limitation by explicitly incorporating the influence of the bandgap in the parameterisation of the electronic specific heat for Si. The specific heat as a function of electronic temperature is calculated using finite temperature density functional theory with three different exchange correlation functionals, each with a characteristic bandgap. These electronic temperature dependent specific heats are employed with two-temperature molecular dynamics to model ion track creation in Si. The results obtained using a specific heat derived from density functional theory showed dramatically reduced defect creation compared to models that used the free electron gas specific heat. As a consequence, the track radii are smaller and in much better agreement with experimental observations. We also observe a correlation between the width of the band gap and the track radius, arising due to the variation in the temperature dependence of the electronic specific heat. PMID:27501917

  4. Population of high spin states in very heavy ion transfer reactions. The experimental evidence

    SciTech Connect

    Guidry, M.W.

    1985-01-01

    Transfer reactions have been studied for some time with light heavy ions such as oxygen. Although states of spin I approx.10 h are sometimes populated in such reactions, it is assumed that collective excitation is small, and the transferred particles are responsible for the angular momentum transfer. In this paper we will discuss a qualitatively different kind of transfer reaction using very heavy ions (A greater than or equal to 40). In these reactions the collective excitation in both the entrance and exit channels is strong, and there may be appreciable angular momentum transfer associated with inelastic excitation. 12 refs., 13 figs.

  5. Determination of heavy metals and halogens in plastics from electric and electronic waste

    SciTech Connect

    Dimitrakakis, Emmanouil; Janz, Alexander; Bilitewski, Bernd; Gidarakos, Evangelos

    2009-10-15

    The presence of hazardous substances and preparations in small waste electrical and electronic equipment (sWEEE) found in the residual household waste stream of the city of Dresden, Germany has been investigated. The content of sWEEE plastics in heavy metals and halogens is determined using handheld X-ray fluorescence analysis (HXRF), elemental analysis by means of atomic absorption spectrometry (AAS) and ion exchange chromatography (IEC). Mean value of results for heavy metals in samples (n = 51) by AAS are 17.4 mg/kg for Pb, 5.7 mg/kg for Cd, 8.4 mg/kg for Cr. The mass fraction of an additive as shown by HXRF (n = 161) can vary over a wide range. Precise deductions as regards sWEEE plastics content in hazardous substances and preparations cannot be made. Additional research would be expedient regarding the influence of hazardous substances to recycling processes, in particular regarding the contamination of clean fractions in the exit streams of a WEEE treatment plant. Suitable standards for calibrating HXRF for use on EEE plastics or complex electr(on)ic components do not exist and should be developed.

  6. Effects of electronic and nuclear stopping power on disorder induced in GaN under swift heavy ion irradiation

    NASA Astrophysics Data System (ADS)

    Moisy, F.; Sall, M.; Grygiel, C.; Balanzat, E.; Boisserie, M.; Lacroix, B.; Simon, P.; Monnet, I.

    2016-08-01

    Wurtzite GaN epilayers, grown on the c-plane of sapphire substrate, have been irradiated with swift heavy ions at different energies and fluences, and thereafter studied by Raman scattering spectroscopy, UV-visible spectroscopy and transmission electron microscopy. Raman spectra show strong structural modifications in the GaN layer. Indeed, in addition to the broadening of the allowed modes, a large continuum and three new modes at approximately 200 cm-1, 300 cm-1 and 670 cm-1 appear after irradiation attributed to disorder-activated Raman scattering. In this case, spectra are driven by the phonon density of states of the material due to the loss of translation symmetry of the lattice induced by defects. It was shown qualitatively that both electronic excitations and elastic collisions play an important role in the disorder induced by irradiation. UV-visible spectra reveal an absorption band at 2.8 eV which is linked to the new mode at 300 cm-1 observed in irradiated Raman spectra and comes from Ga-vacancies. These color centers are produced by elastic collisions (without any visible effect of electronic excitations).

  7. Organic substrates as electron donors in permeable reactive barriers for removal of heavy metals from acid mine drainage.

    PubMed

    Kijjanapanich, P; Pakdeerattanamint, K; Lens, P N L; Annachhatre, A P

    2012-12-01

    This research was conducted to select suitable natural organic substrates as potential carbon sources for use as electron donors for biological sulphate reduction in a permeable reactive barrier (PRB). A number of organic substrates were assessed through batch and continuous column experiments under anaerobic conditions with acid mine drainage (AMD) obtained from an abandoned lignite coal mine. To keep the heavy metal concentration at a constant level, the AMD was supplemented with heavy metals whenever necessary. Under anaerobic conditions, sulphate-reducing bacteria (SRB) converted sulphate into sulphide using the organic substrates as electron donors. The sulphide that was generated precipitated heavy metals as metal sulphides. Organic substrates, which yielded the highest sulphate reduction in batch tests, were selected for continuous column experiments which lasted over 200 days. A mixture of pig-farm wastewater treatment sludge, rice husk and coconut husk chips yielded the best heavy metal (Fe, Cu, Zn and Mn) removal efficiencies of over 90%. PMID:23437664

  8. Higher-point conformal blocks and entanglement entropy in heavy states

    NASA Astrophysics Data System (ADS)

    Banerjee, Pinaki; Datta, Shouvik; Sinha, Ritam

    2016-05-01

    We consider conformal blocks of two heavy operators and an arbitrary number of light operators in a (1+1)- d CFT with large central charge. Using the monodromy method, these higher-point conformal blocks are shown to factorize into products of 4-point conformal blocks in the heavy-light limit for a class of OPE channels. This result is reproduced by considering suitable worldline configurations in the bulk conical defect geometry. We apply the CFT results to calculate the entanglement entropy of an arbitrary number of disjoint intervals for heavy states. The corresponding holographic entanglement entropy calculated via the minimal area prescription precisely matches these results from CFT. Along the way, we briefly illustrate the relation of these conformal blocks to Riemann surfaces and their associated moduli space.

  9. 45 CFR 265.6 - Must States file reports electronically?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... (ASSISTANCE PROGRAMS), ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES DATA COLLECTION AND REPORTING REQUIREMENTS § 265.6 Must States file reports electronically? Each State must...

  10. Electronic stopping powers for heavy ions in SiC and SiO{sub 2}

    SciTech Connect

    Jin, K.; Xue, H.; Zhang, Y. Weber, W. J.; Zhu, Z.; Grove, D. A.; Xue, J.

    2014-01-28

    Accurate information on electronic stopping power is fundamental for broad advances in materials science, electronic industry, space exploration, and sustainable energy technologies. In the case of slow heavy ions in light targets, current codes and models provide significantly inconsistent predictions, among which the Stopping and Range of Ions in Matter (SRIM) code is the most commonly used one. Experimental evidence, however, has demonstrated considerable errors in the predicted ion and damage profiles based on SRIM stopping powers. In this work, electronic stopping powers for Cl, Br, I, and Au ions are experimentally determined in two important functional materials, SiC and SiO{sub 2}, based on a single ion technique, and new electronic stopping power values are derived over the energy regime from 0 to 15 MeV, where large deviations from the SRIM predictions are observed. As an experimental validation, Rutherford backscattering spectrometry (RBS) and secondary ion mass spectrometry (SIMS) are utilized to measure the depth profiles of implanted Au ions in SiC for energies from 700 keV to 15 MeV. The measured ion distributions by both RBS and SIMS are considerably deeper than the SRIM predictions, but agree well with predictions based on our derived stopping powers.

  11. Electronic Stopping Powers For Heavy Ions In SiC And SiO2

    SciTech Connect

    Jin, Ke; Zhang, Y.; Zhu, Zihua; Grove, David A.; Xue, H.; Xue, Jianming; Weber, William J.

    2014-01-24

    Accurate information on electronic stopping power is fundamental for broad advances in materials science, electronic industry, space exploration, and sustainable energy technologies. In the case of slow heavy ions in light targets, current codes and models provide significantly inconsistent predictions, among which the Stopping and Range of Ions in Matter (SRIM) code is the most commonly used one. Experimental evidence, however, has demonstrated considerable errors in the predicted ion and damage profiles based on SRIM stopping powers. In this work, electronic stopping powers for Cl, Br, I, and Au ions are experimentally determined in two important functional materials, SiC and SiO2, based on a single ion technique, and new electronic stopping power values are derived over the energy regime from 0 to 15 MeV, where large deviations from the SRIM predictions are observed. As an experimental validation, Rutherford backscattering spectrometry (RBS) and secondary ion mass spectrometry (SIMS) are utilized to measure the depth profiles of implanted Au ions in SiC for energies from 700 keV to 15MeV. The measured ion distributions by both RBS and SIMS are considerably deeper than the SRIM predictions, but agree well with predictions based on our derived stopping powers.

  12. Parametrized equation of state for electron liquids in the Singwi-Tosi-Land-Sjolander aproximation

    NASA Technical Reports Server (NTRS)

    Tanaka, S.; Mitake, S.; Ichimaru, S.

    1985-01-01

    Results are reported of a theoretical study of an equation of state for electron liquids (one-component plasmas of electrons embedded in a uniform neutralizing background of positive charges), where there is an interplay between the strong Coulomb-coupling effect and the degrees of Fermi degeneracy. Calculations are based on the Singwi-Tosi-Land-Sjolander approximation (1968). The calculated results are parametrized in the form of analytic formulas for the interaction and excess free energies, which are applicable over a wide range of parameters as long as the electrons are in a paramagnetic fluid state. Unlike the present study, earlier studies concentrated on plasmas where the Fermi degeneracy parameter tended either to zero or to infinity, thus excluding many actual plasmas (stellar interiors, heavy planets such as Jupiter, plasmas in projected inertial confinement fusion experiments, and the liquid metals).

  13. Electronic stopping power for heavy ions in SiC and SiO2

    SciTech Connect

    Jin, Ke; Zhang, Yanwen; Zhu, Zihua; Grove, David A.; Xue, Haizhou; Xue, Jianming; Weber, William J

    2014-01-01

    Accurate information of electronic stopping power is fundamental for broad advances in electronic industry, space exploration, national security, and sustainable energy technologies. The Stopping and Range of Ions in Matter (SRIM) code has been widely applied to predict stopping powers and ion distributions for decades. Recent experimental results have, however, shown considerable errors in the SRIM predictions for stopping of heavy ions in compounds containing light elements, indicating an urgent need to improve current stopping power models. The electronic stopping powers of 35Cl, 80Br, 127I, and 197Au ions are experimentally determined in two important functional materials, SiC and SiO2, from tens to hundreds keV/u based on a single ion technique. By combining with the reciprocity theory, new electronic stopping powers are suggested in a region from 0 to 15 MeV, where large deviations from SRIM predictions are observed. For independent experimental validation of the electronic stopping powers we determined, Rutherford backscattering spectrometry (RBS) and secondary ion mass spectrometry (SIMS) are utilized to measure the depth profiles of implanted Au ions in SiC with energies from 700 keV to 15 MeV. The measured ion distributions from both RBS and SIMS are considerably deeper (up to ~30%) than the predictions from the commercial SRIM code. In comparison, the new electronic stopping power values are utilized in a modified TRIM-85 (the original version of the SRIM) code, M-TRIM, to predict ion distributions, and the results are in good agreement with the experimentally measured ion distributions.

  14. Constraining the equation of state of superhadronic matter from heavy-ion collisions

    DOE PAGESBeta

    Pratt, Scott; Sorensen, Paul; Sangaline, Evan; Wang, Hui

    2015-05-19

    The equation of state of QCD matter for temperatures near and above the quark-hadron transition (~165 MeV) is inferred within a Bayesian framework through the comparison of data from the Relativistic Heavy Ion Collider and from the Large Hadron Collider to theoretical models. State-of-the-art statistical techniques are applied to simultaneously analyze multiple classes of observables while varying 14 independent model parameters. Thus, the resulting posterior distribution over possible equations of state is consistent with results from lattice gauge theory.

  15. Constraining the Equation of State of Superhadronic Matter from Heavy-Ion Collisions.

    PubMed

    Pratt, Scott; Sangaline, Evan; Sorensen, Paul; Wang, Hui

    2015-05-22

    The equation of state of QCD matter for temperatures near and above the quark-hadron transition (∼165  MeV) is inferred within a Bayesian framework through the comparison of data from the Relativistic Heavy Ion Collider and from the Large Hadron Collider to theoretical models. State-of-the-art statistical techniques are applied to simultaneously analyze multiple classes of observables while varying 14 independent model parameters. The resulting posterior distribution over possible equations of state is consistent with results from lattice gauge theory. PMID:26047223

  16. Electron states in semiconductor quantum dots

    SciTech Connect

    Dhayal, Suman S.; Ramaniah, Lavanya M.; Ruda, Harry E.; Nair, Selvakumar V.

    2014-11-28

    In this work, the electronic structures of quantum dots (QDs) of nine direct band gap semiconductor materials belonging to the group II-VI and III-V families are investigated, within the empirical tight-binding framework, in the effective bond orbital model. This methodology is shown to accurately describe these systems, yielding, at the same time, qualitative insights into their electronic properties. Various features of the bulk band structure such as band-gaps, band curvature, and band widths around symmetry points affect the quantum confinement of electrons and holes. These effects are identified and quantified. A comparison with experimental data yields good agreement with the calculations. These theoretical results would help quantify the optical response of QDs of these materials and provide useful input for applications.

  17. Heavy metal pollution of river Yamuna in the industrially developing state of Haryana.

    PubMed

    Kaushik, A; Jain, S; Dawra, J; Sahu, R; Kaushik, C P

    2001-10-01

    Heavy metal concentrations viz. Fe, Ni, Pb, Cd, Co, Zn in the river Yamuna flowing along the state of Haryana through Delhi have been reported selecting 16 stations covering the upstream and downstream stations for major industrial complexes of the state. While Fe, Ni and Co concentrations exceeded the maximum permissible limits prescribed for drinking all along the river, the Cd concentrations crossed the acceptable standards in Delhi downstream. The Pb concentrations declined in the eutrophicated Delhi downstream while Zn concentrations remained within desirable limits throughout. Peak concentrations were recorded in Delhi downstream for Fe and at Sonepat-Gohana downstream for Ni, Co & Zn, which matched with the type of industrial inputs viz. Iron-works and the electroplating, galvanizing & cycle industries, respectively. The status of heavy metal pollution of the river has been discussed with respect to possible impacts on human health and aquatic life. PMID:12395521

  18. Probing the nuclear equation-of-state and the symmetry energy with heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Verde, Giuseppe

    2014-03-01

    The present status of studies aimed at constraining the nuclear equation of state with heavy-ion collision dynamics is presented. Multifragmentation phenomena, including their isotopic distributions, charge correlations and emission time-scales, may revel the existence of liquid-gas transitions in the phase diagram. Exploring the isotopic degree of freedom in nuclear dynamics is then required in order to constrain the equation of state of asymmetric nuclear matter which presently represents a major priority due to its relevance to both nuclear physics and astrophysics. Some observables that have successfully constrained the density dependence of the symmetry energy are presented, such as neutron-proton yield ratios and isospin diffusion and drift phenomena. The reported results and status of the art is discussed by also considering some of the present problems and some future perspectives for the heavy-ion collision community.

  19. Trends in solid state electronics, part 2

    NASA Technical Reports Server (NTRS)

    Gassaway, J. D.

    1972-01-01

    Developments in the fields of semiconductors and magnetics are surveyed. Materials, devices, theory, and fabrication technology are discussed. Important events up until the present time are reported, and events are interpreted through historical perspective. A brief analysis of forces which have driven the development of today's electronic technology and some projections of present trends are given. More detailed discussions are presented for four areas of contemporary interest: amorphous semiconductors, bubble domain devices, charge-coupled devices, and electron and ion beam techniques. Beam addressed magnetic memories are reviewed to a lesser extent.

  20. On the universal scaling in the electronic stopping cross section for heavy ion projectiles

    NASA Astrophysics Data System (ADS)

    Cabrera-Trujillo, R.; Martínez-Flores, C.; Trujillo-López, L. N.; Serkovic-Loli, L. N.

    2016-02-01

    Energy deposition of heavy ions when penetrating a material is of crucial importance in determining the damage to materials with implications in areas such as material science, plasma physics, radiotherapy and dosimetry. Due to the N-body electron problem, it has been thought that the electronic stopping cross section is unique for a given projectile-target combination and differs from system to system. In this work, we show that within the Bethe theory, there is a universal scaling when the electronic stopping cross sections and projectile kinetic energy are scaled properly in terms of the target mean excitation energy, ?, for all projectile-target combinations. We show that the scaling is given by ? as a function of ?, thus showing the importance of the characterization of the mean excitation energy. The scaling law expresses a systematic and universal behavior among complex projectile-target systems in the energy deposition, characterized by the minimum momentum transfer during the slowing down process. We provide an analytic expression for the universal scaling law for the stopping cross section of any projectile-target combination valid at high collision energies. Finally, we verify the universal scaling law by comparison to atomic and molecular experimental data available in the literature. We expect our findings will motivate further experimental work to verify our universal scaling for more complex systems in the absence of experimental data.

  1. Recent results on fast electron production induced by energetic heavy ions on thin solid targets

    NASA Astrophysics Data System (ADS)

    Lanzanò, G.; Anzalone, A.; Arena, N.; De Filippo, E.; Geraci, M.; Giustolisi, F.; Pagano, A.; Rothard, H.; Volant, C.

    2003-08-01

    In order to study the emission of energetic electrons induced by the impact of swift heavy ions on thin solid targets, we carried out a series of experiments at the Superconducting Cyclotron of the Catania Laboratori Nazionali del Sud (LNS) in November and December 2001. We bombarded solid thin targets, ranging from carbon to bismuth, with different ion beams at fixed velocity, i.e. ˜23 MeV/nucleon 197Au 36+, 58Ni 14+ and 12C 3+. Absolute velocity spectra were measured in a wide laboratory angular range, from 1.5° to 175°. At forward angles, besides the well-known convoy and binary encounter components with the beam velocity and two times the beam velocity respectively, we observe also a high velocity tail and an intermediate velocity component. At backward laboratory angles, the spectra remain complex, still presenting an energetic tail. These electron velocity spectra strongly depend on the beam and target atomic numbers. We suggest a Fermi-Shuttle (or multiscattering) mechanism and an in-flight-emission of projectile Auger electrons to explain some of the observed features in the velocity spectra.

  2. Structural manipulation in Ge by swift heavy ions governed by electron-phonon coupling strength

    NASA Astrophysics Data System (ADS)

    Hooda, S.; Satpati, B.; Ojha, S.; Kumar, T.; Kanjilal, D.; Kabiraj, D.

    2015-04-01

    The effect of electron-phonon coupling strength in structural manipulation of different degrees of pre-damaged Ge by swift heavy ions (SHI) has been investigated. Starting with c-Ge (100), three sets of samples were prepared with various degrees of damage, i.e. isolated amorphous pockets, connected amorphous zones and continuous amorphous layer by 100 keV Ar ion irradiation. Structural changes in these samples induced by 100 MeV Ag ions were investigated by RBS/C, micro-Raman spectroscopy and XTEM studies. Results show that the sample having isolated amorphous pockets undergoes re-crystallization whereas the sample having uniform amorphous layer shows volume expansion with formation of nanorod-like structures, after SHI irradiation. In this work, it is emphasized that the different degrees of pre-damage have a prominent role against SHI-induced structural manipulation under different laws or equations.

  3. Distortion effects in electron excitation of hydrogen atoms by impact of heavy ions

    SciTech Connect

    Ramirez, C.A.; Rivarola, R.D.

    1995-12-01

    Electron excitation from the fundamental state of hydrogen atoms by impact of bare ions is studied at intermediate and high collision velocities. Total cross sections for final {ital np} states by impact of protons, alpha particles, and He{sup +} ions are calculated using the symmetric eikonal approximation and compared with experimental data. This comparison supports the existence of distortion effects recently predicted by Bugacov and co-workers [Phys. Rev. A {bold 47}, 1052 (1993)]. The validity of scaling laws is analyzed.

  4. Modifications in structural and electronic properties of TiO{sub 2} thin films using swift heavy ion irradiation

    SciTech Connect

    Thakur, Hardeep; Sharma, K. K.; Kumar, Ravi; Thakur, P.; Brookes, N. B.; Pratap Singh, Abhinav; Kumar, Yogesh; Gautam, S.; Chae, K. H.

    2011-10-15

    We report on the structural and electronic properties of swift heavy ion (SHI) irradiated pristine TiO{sub 2} thin films, deposited by radio frequency magnetron sputtering on sapphire substrates. The high resolution x-ray diffraction and Raman measurements show a structural phase transition from anatase to admixture of brookite and rutile phases of TiO{sub 2} with increasing SHI fluence followed by a significant distortion in the TiO{sub 6} octahedra. The modification in the electronic structure stimulated by SHI irradiation has been investigated using x-ray absorption (XAS) experiments at the O K and Ti L{sub 3,2} absorption edges. The O K edge spectra clearly indicate the splitting of the pre-edge spectral features having t{sub 2g} and e{sub g} symmetry bands due to structural disorder/distortion induced by irradiation. The intensity of the SHI generated components at the O K edge increases monotonically, which can be correlated to the modification in unoccupancies associated with O 2 p orbitals hybridized with Ti 3 d states. The XAS spectra at the Ti L{sub 3,2} edge further authenticate that SHI creates a controlled structural disorder/distortion in the TiO{sub 6} octahedra.

  5. Electron and electron-hole quasiparticle states in a driven quantum contact

    NASA Astrophysics Data System (ADS)

    Vanević, Mihajlo; Gabelli, Julien; Belzig, Wolfgang; Reulet, Bertrand

    2016-01-01

    We study the many-body electronic state created by a time-dependent drive of a mesoscopic contact. The many-body state is expressed manifestly in terms of single-electron and electron-hole quasiparticle excitations with the amplitudes and probabilities of creation which depend on the details of the applied voltage. We experimentally probe the time dependence of the constituent electronic states by using an analog of the optical Hong-Ou-Mandel correlation experiment where electrons emitted from the terminals with a relative time delay collide at the contact. The electron wave packet overlap is directly related to the current noise power in the contact. We have confirmed the time dependence of the electronic states predicted theoretically by measurements of the current noise power in a tunnel junction under harmonic excitation.

  6. Closing the wedge: Search strategies for extended Higgs sectors with heavy flavor final states

    NASA Astrophysics Data System (ADS)

    Gori, Stefania; Kim, Ian-Woo; Shah, Nausheen R.; Zurek, Kathryn M.

    2016-04-01

    We consider search strategies for an extended Higgs sector at the high-luminosity LHC14 utilizing multitop final states. In the framework of a two Higgs doublet model, the purely top final states (t t ¯ , 4 t ) are important channels for heavy Higgs bosons with masses in the wedge above 2 mt and at low values of tan β , while a 2 b 2 t final state is most relevant at moderate values of tan β . We find, in the t t ¯H channel, with H →t t ¯, that both single and three lepton final states can provide statistically significant constraints at low values of tan β for mA as high as ˜750 GeV . When systematics on the t t ¯ background are taken into account, however, the three lepton final state is more powerful, though the precise constraint depends fairly sensitively on lepton fake rates. We also find that neither 2 b 2 t nor t t ¯ final states provide constraints on additional heavy Higgs bosons with couplings to tops smaller than the top Yukawa due to expected systematic uncertainties in the t t ¯ background.

  7. Electronic states and stability of selenium clusters

    NASA Astrophysics Data System (ADS)

    Li, Z. Q.; Yu, J. Z.; Ohno, K.; Gu, B. L.; Czajka, R.; Kasuya, A.; Nishina, Y.; Kawazoe, Y.

    1995-07-01

    Electronic structures and stability of Sen (n=3,4,5,6,7,8) clusters have been studied by using the discrete variational method in the framework of the local-density approximation. Binding energy, ionization potential, affinity energy, and other electronic properties using the structure models of Hohl et al. [Chem. Phys. Lett. 139, 540 (1987)] are presented and compared with the available experiments. In addition, a rectangular lattice arrangement of selenium clusters has been fabricated on highly oriented pyrolytic graphite, and examined by the scanning tunnel microscope image which was found to consist of a 0.72×0.85 nm2 lattice spacing with individual molecules of 0.53+/-0.05 nm in diameter. Theoretical calculations reproduce well the experimental observations.

  8. Heavy surface state in a possible topological Kondo insulator: Magnetothermoelectric transport on the (011) plane of SmB6

    DOE PAGESBeta

    Luo, Yongkang; Chen, Hua; Dai, Jianhui; Xu, Zhu -an; Thompson, J. D.

    2015-02-25

    Motivated by the high sensitivity to Fermi surface topology and scattering mechanisms in magnetothermoelectric transport, we have measured the thermopower and Nernst effect on the (011) plane of the proposed topological Kondo insulator SmB6. These experiments, together with electrical resistivity and Hall effect measurements, suggest that the (011) plane also harbors a metallic surface with an effective mass on the order of 10–102 m0. The surface and bulk conductances are well distinguished in these measurements and are categorized into metallic and nondegenerate semiconducting regimes, respectively. As a result, electronic correlations play an important role in enhancing scattering and also contributemore » to the heavy surface state.« less

  9. Using heavy-ion collisions to elucidate the asymmetric equation-of-state

    NASA Astrophysics Data System (ADS)

    Yennello, Sherry; McIntosh, Alan

    2016-06-01

    The nuclear equation-of-state impacts a number of nuclear properties as well as astrophysical processes. The asymmetric term of the equation-of-state, which describes the behavior away from N=Z, has significant uncertainty. Giant resonances and nuclear masses can elucidate the asymmetry energy for cold normal-density nuclei. Heavy-ion collisions can be used to probe nuclear matter at higher temperatures and densities away from saturation density. The temperatures that are attained in these nuclear collisions are predicted to depend on the isospin asymmetry. In this work we present evidence of the asymmetry dependence of the nuclear caloric curve.

  10. Properties of cylindrical and spherical heavy ion-acoustic solitary and shock structures in a multispecies plasma with superthermal electrons

    NASA Astrophysics Data System (ADS)

    Shah, M. G.; Rahman, M. M.; Hossen, M. R.; Mamun, A. A.

    2016-02-01

    A theoretical investigation on heavy ion-acoustic (HIA) solitary and shock structures has been accomplished in an unmagnetized multispecies plasma consisting of inertialess kappa-distributed superthermal electrons, Boltzmann light ions, and adiabatic positively charged inertial heavy ions. Using the reductive perturbation technique, the nonplanar (cylindrical and spherical) Kortewg-de Vries (KdV) and Burgers equations have been derived. The solitary and shock wave solutions of the KdV and Burgers equations, respectively, have been numerically analyzed. The effects of superthermality of electrons, adiabaticity of heavy ions, and nonplanar geometry, which noticeably modify the basic features (viz. polarity, amplitude, phase speed, etc.) of small but finite amplitude HIA solitary and shock structures, have been carefully investigated. The HIA solitary and shock structures in nonplanar geometry have been found to distinctly differ from those in planar geometry. Novel features of our present attempt may contribute to the physics of nonlinear electrostatic perturbation in astrophysical and laboratory plasmas.

  11. Single Crystal Growth and Electronic State of UPd2Cd20

    NASA Astrophysics Data System (ADS)

    Doto, Hiroshi; Hirose, Yusuke; Honda, Fuminori; Li, Dexin; Homma, Yoshiya; Aoki, Dai; Settai, Rikio

    We succeeded in growing single crystals of UPd2Cd20 by the Cd self-flux method. This compound crystallizes in the cubic CeCr2Al20-type structure. From the low-temperature electrical resistivity and Kadowaki-Woods relation, the electronic specific heat coefficient γ is estimated to be about 400mJ/mol ·K2. The magnetic susceptibility of UPd2Cd20 indicates a broad max-imum at 6.6K and a rapid decrease at 5.0K, which correspond to the formation of the heavy fermion state and the antiferromagnetic transition, respectively. These experimental results strongly suggest that UPd2Cd20 is a new heavy fermion antiferromagnet.

  12. Intense beam production of highly charged heavy ions by the superconducting electron cyclotron resonance ion source SECRAL (invited)a)

    NASA Astrophysics Data System (ADS)

    Zhao, H. W.; Sun, L. T.; Zhang, X. Z.; Guo, X. H.; Cao, Y.; Lu, W.; Zhang, Z. M.; Yuan, P.; Song, M. T.; Zhao, H. Y.; Jin, T.; Shang, Y.; Zhan, W. L.; Wei, B. W.; Xie, D. Z.

    2008-02-01

    There has been increasing demand to provide higher beam intensity and high enough beam energy for heavy ion accelerator and some other applications, which has driven electron cyclotron resonance (ECR) ion source to produce higher charge state ions with higher beam intensity. One of development trends for highly charged ECR ion source is to build new generation ECR sources by utilization of superconducting magnet technology. SECRAL (superconducting ECR ion source with advanced design in Lanzhou) was successfully built to produce intense beams of highly charged ion for Heavy Ion Research Facility in Lanzhou (HIRFL). The ion source has been optimized to be operated at 28GHz for its maximum performance. The superconducting magnet confinement configuration of the ion source consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamping. An innovative design of SECRAL is that the three axial solenoid coils are located inside of the sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils. For 28GHz operation, the magnet assembly can produce peak mirror fields on axis of 3.6T at injection, 2.2T at extraction, and a radial sextupole field of 2.0T at plasma chamber wall. During the commissioning phase at 18GHz with a stainless steel chamber, tests with various gases and some metals have been conducted with microwave power less than 3.5kW by two 18GHz rf generators. It demonstrates the performance is very promising. Some record ion beam intensities have been produced, for instance, 810eμA of O7+, 505eμA of Xe20+, 306eμA of Xe27+, and so on. The effect of the magnetic field configuration on the ion source performance has been studied experimentally. SECRAL has been put into operation to provide highly charged ion beams for HIRFL facility since May 2007.

  13. Intense beam production of highly charged heavy ions by the superconducting electron cyclotron resonance ion source SECRAL.

    PubMed

    Zhao, H W; Sun, L T; Zhang, X Z; Guo, X H; Cao, Y; Lu, W; Zhang, Z M; Yuan, P; Song, M T; Zhao, H Y; Jin, T; Shang, Y; Zhan, W L; Wei, B W; Xie, D Z

    2008-02-01

    There has been increasing demand to provide higher beam intensity and high enough beam energy for heavy ion accelerator and some other applications, which has driven electron cyclotron resonance (ECR) ion source to produce higher charge state ions with higher beam intensity. One of development trends for highly charged ECR ion source is to build new generation ECR sources by utilization of superconducting magnet technology. SECRAL (superconducting ECR ion source with advanced design in Lanzhou) was successfully built to produce intense beams of highly charged ion for Heavy Ion Research Facility in Lanzhou (HIRFL). The ion source has been optimized to be operated at 28 GHz for its maximum performance. The superconducting magnet confinement configuration of the ion source consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamping. An innovative design of SECRAL is that the three axial solenoid coils are located inside of the sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils. For 28 GHz operation, the magnet assembly can produce peak mirror fields on axis of 3.6 T at injection, 2.2 T at extraction, and a radial sextupole field of 2.0 T at plasma chamber wall. During the commissioning phase at 18 GHz with a stainless steel chamber, tests with various gases and some metals have been conducted with microwave power less than 3.5 kW by two 18 GHz rf generators. It demonstrates the performance is very promising. Some record ion beam intensities have been produced, for instance, 810 e microA of O(7+), 505 e microA of Xe(20+), 306 e microA of Xe(27+), and so on. The effect of the magnetic field configuration on the ion source performance has been studied experimentally. SECRAL has been put into operation to provide highly charged ion beams for HIRFL facility since May 2007. PMID:18315105

  14. The viscosity cross section for electron scattering from the heavy noble gases

    NASA Astrophysics Data System (ADS)

    Stauffer, Allan; McEachran, Robert

    2014-10-01

    The viscosity cross section is defined in terms of the elastic differential cross section σ (θ) as σv =∫0 π (1 -cos2 θ) sin θ σ (θ) dθ and appears in the Boltzmann equation for the electron distribution function in velocity space. If this distribution function is expanded in Legendre polynomials, the viscosity cross section arises from the third term. Normally, only the first two terms in this expansion are retained in the solution of the Boltzmann equation. We have recently published results for the elastic and momentum transfer cross section for electron scattering from the heavy noble gases (argon, krypton and xenon) using our complex, relativistic optical potential method which includes the effect of excitation and ionization channels on the elastic cross sections. We also provided simple analytic fits to these cross sections to aid in plasma modelling calculations. We will present similar results for the viscosity cross sections for these gases including fits using similar analytic functions. By including the third term in the expansion of the Boltzmann equation which depends on this cross section, an evaluation of the accuracy of the two-term solution can be made.

  15. Operational head-on beam-beam compensation with electron lenses in the Relativistic Heavy Ion Collider

    DOE PAGESBeta

    Fischer, W.; Gu, X.; Altinbas, Z.; Costanzo, M.; Hock, J.; Liu, C.; Luo, Y.; Marusic, A.; Michnoff, R.; Miller, T. A.; et al

    2015-12-23

    Head-on beam-beam compensation has been implemented in the Relativistic Heavy Ion Collider (RHIC) in order to increase the luminosity delivered to the experiments. We discuss the principle of combining a lattice for resonance driving term compensation and an electron lens for tune spread compensation. We describe the electron lens technology and its operational use. As of this date the implemented compensation scheme approximately doubled the peak and average luminosities.

  16. Heavy Ion Collisions and Tests of the Supernova Equation of State

    NASA Astrophysics Data System (ADS)

    Hagel, K.; Hempel, M.; Natowitz, J. B.; Röpke, G.; Typel, S.; Wuenschel, S.; Wada, R.; Barbui, M.; Schmidt, K.

    2015-10-01

    Understanding the evolution of core-collapse supernovae and the properties of the neutrinosphere requires systematic information on the properties of nuclear matter at a wide range of densities and temperatures. Central collisions in heavy ion reactions at intermediate energies produce nuclear matter on a microscopic scale that has a wide range of density and temperature and thus provide the possibility of probing conditions similar to those of core-collapse supernovae. Hot early reaction stage sources in violent collisions of heavy ion reactions, denoted as femtonovae, are identified and analyzed in the context of a coalescence model. The analysis yields various quantities indicate that temperature and density similar to those near the neutrinosphere are achieved. These results from these analyses are compared to the results of various supernovae simulations and thus provide insight into the supernova equation of state and thus indicate which ingredients in the simulations are important.

  17. Mitochondrial Electron Transport Chain in Heavy Metal-Induced Neurotoxicity: Effects of Cadmium, Mercury, and Copper

    PubMed Central

    Belyaeva, Elena A.; Sokolova, Tatyana V.; Emelyanova, Larisa V.; Zakharova, Irina O.

    2012-01-01

    To clarify the role of mitochondrial electron transport chain (mtETC) in heavy-metal-induced neurotoxicity, we studied action of Cd2+, Hg2+, and Cu2+ on cell viability, intracellular reactive oxygen species formation, respiratory function, and mitochondrial membrane potential of rat cell line PC12. As found, the metals produced, although in a different way, dose- and time-dependent changes of all these parameters. Importantly, Cd2+ beginning from 10 [mu]M and already at short incubation time (3 h) significantly inhibited the FCCP-uncoupled cell respiration; besides, practically the complete inhibition of the respiration was reached after 3 h incubation with 50 [mu]M Hg2+ or 500 [mu]M Cd2+, whereas even after 48 h exposure with 500 [mu]M Cu2+, only a 50% inhibition of the respiration occurred. Against the Cd2+-induced cell injury, not only different antioxidants and mitochondrial permeability transition pore inhibitors were protective but also such mtETC effectors as FCCP and stigmatellin (complex III inhibitor). However, all mtETC effectors used did not protect against the Hg2+- or Cu2+-induced cell damage. Notably, stigmatellin was shown to be one of the strongest protectors against the Cd2+-induced cell damage, producing a 15–20% increase in the cell viability. The mechanisms of the mtETC involvement in the heavy-metal-induced mitochondrial membrane permeabilization and cell death are discussed. PMID:22619586

  18. Heavy Flavor Dynamics in Relativistic Heavy-ion Collisions

    NASA Astrophysics Data System (ADS)

    Cao, Shanshan

    addition, various transport properties of heavy quarks are investigated within our numerical framework, such as the thermalization process of heavy quarks inside the QGP, and how the initial configuration of the QGP as well as its properties affect the final state spectra and the elliptic flow of heavy mesons and their decay electrons. The effects of initial state fluctuations in heavy-ion collisions are also studied and found to enhance the heavy quark energy loss in a (2+1)-dimensional boost invariant scenario. Furthermore, a new set of observables -- heavy-flavor-tagged angular correlation functions -- are explored and found to be potential candidates for distinguishing different energy loss mechanisms of heavy quarks inside the QGP.

  19. Electron beam technology for multipollutant emissions control from heavy fuel oil-fired boiler.

    PubMed

    Chmielewski, Andrzej G; Ostapczuk, Anna; Licki, Janusz

    2010-08-01

    The electron beam treatment technology for purification of exhaust gases from the burning of heavy fuel oil (HFO) mazout with sulfur content approximately 3 wt % was tested at the Institute of Nuclear Chemistry and Technology laboratory plant. The parametric study was conducted to determine the sulfur dioxide (SO2), oxides of nitrogen (NO(x)), and polycyclic aromatic hydrocarbon (PAH) removal efficiency as a function of temperature and humidity of irradiated gases, absorbed irradiation dose, and ammonia stoichiometry process parameters. In the test performed under optimal conditions with an irradiation dose of 12.4 kGy, simultaneous removal efficiencies of approximately 98% for SO2, and 80% for NO(x) were recorded. The simultaneous decrease of PAH and one-ringed aromatic hydrocarbon (benzene, toluene, and xylenes [BTX]) concentrations was observed in the irradiated flue gas. Overall removal efficiencies of approximately 42% for PAHs and 86% for BTXs were achieved with an irradiation dose 5.3 kGy. The decomposition ratio of these compounds increased with an increase of absorbed dose. The decrease of PAH and BTX concentrations was followed by the increase of oxygen-containing aromatic hydrocarbon concentrations. The PAH and BTX decomposition process was initialized through the reaction with hydroxyl radicals that formed in the electron beam irradiated flue gas. Their decomposition process is based on similar principles as the primary reaction concerning SO2 and NO(x) removal; that is, free radicals attack organic compound chains or rings, causing volatile organic compound decomposition. Thus, the electron beam flue gas treatment (EBFGT) technology ensures simultaneous removal of acid (SO2 and NO(x)) and organic (PAH and BTX) pollutants from flue gas emitted from burning of HFO. This technology is a multipollutant emission control technology that can be applied for treatment of flue gas emitted from coal-, lignite-, and HFO-fired boilers. Other thermal processes such

  20. Complex Study of Electronic States and Spectra of 3-Nitroformazans

    NASA Astrophysics Data System (ADS)

    Valiev, R. R.; Drozdova, A. K.; Petunin, P. V.; Postnikov, P. S.; Trusova, M. E.; Cherepanov, V. N.

    2016-06-01

    A theoretical and experimental study of electronic states and the absorption spectra of 3-nitroformazan molecules was conducted. The results of the study show that the first electron transition is σ→π-transition, and the second one is π→π-transition. The energies of the transitions calculated using methods RI-CC2 and TDDFT correlate well with the experimental measurements. The dependence of the first electron transition wavenumber on the degree of electron donating and accepting of substitutituents was studied using empirical constants. High correlation between the constants of Hammett, Braun, and wavenumbers (TDDFT) of the first electron transition shows that the description of electronic states of the studied 3-nitroformazans is correct.

  1. Lifetimes of electronic excitations in unoccupied surface states and the image potential states on Pd(110)

    SciTech Connect

    Tsirkin, S. S. Eremeev, S. V.; Chulkov, E. V.

    2012-10-15

    The contribution of inelastic electron-electron scattering to the decay rate of excitations in the surface states and first two image potential states at the Y-bar point on the surface is calculated in the GW approximation, and the quasi-momentum dependence of the corresponding contribution for the surface states is analyzed. The mechanisms of electron scattering in these states are studied, and the temperature dependence of the excitation lifetime is analyzed with allowance for the contribution of the electron-phonon interaction calculated earlier.

  2. Flow analysis of heavy metals in a pilot-scale incinerator for residues from waste electrical and electronic equipment dismantling.

    PubMed

    Long, Yu-Yang; Feng, Yi-Jian; Cai, Si-Shi; Ding, Wei-Xu; Shen, Dong-Sheng

    2013-10-15

    The large amount of residues generated from dismantling waste electrical and electronic equipment (WEEE) results in a considerable environmental burden. We used material flow analysis to investigate heavy metal behavior in an incineration plant in China used exclusively to incinerate residues from WEEE dismantling. The heavy metals tested were enriched in the bottom and fly ashes after incineration. However, the contents of heavy metals in the bottom ash, fly ash and exhaust gas do not have a significant correlation with that of the input waste. The evaporation and recondensation behavior of heavy metals caused their contents to differ with air pollution control equipment because of the temperature difference during gas venting. Among the heavy metals tested, Cd had the strongest tendency to transfer during incineration (TCd=69.5%) because it had the lowest melting point, followed by Cu, Ni, Pb and Zn. The exchangeable and residual fractions of heavy metals increased substantially in the incineration products compared with that of the input residues. Although the mass of residues from WEEE dismantling can be reduced by 70% by incineration, the safe disposal of the metal-enriched bottom and fly ashes is still required. PMID:23973476

  3. Electronic aperture control devised for solid state imaging system

    NASA Technical Reports Server (NTRS)

    Anders, R. A.; Callahan, D. E.; Mc Cann, D. H.

    1968-01-01

    Electronic means of performing the equivalent of automatic aperture control has been devised for the new class of television cameras that incorporates a solid state imaging device in the form of phototransistor mosaic sensors.

  4. Crossover from a heavy fermion to intermediate valence state in noncentrosymmetric Yb2Ni12(P,As)7.

    PubMed

    Jiang, W B; Yang, L; Guo, C Y; Hu, Z; Lee, J M; Smidman, M; Wang, Y F; Shang, T; Cheng, Z W; Gao, F; Ishii, H; Tsuei, K D; Liao, Y F; Lu, X; Tjeng, L H; Chen, J M; Yuan, H Q

    2015-01-01

    We report measurements of the physical properties and electronic structure of the hexagonal compounds Yb2Ni12Pn7 (Pn = P, As) by measuring the electrical resistivity, magnetization, specific heat and partial fluorescence yield x-ray absorption spectroscopy (PFY-XAS). These demonstrate a crossover upon reducing the unit cell volume, from an intermediate valence state in Yb2Ni12As7 to a heavy-fermion paramagnetic state in Yb2Ni12P7, where the Yb is nearly trivalent. Application of pressure to Yb2Ni12P7 suppresses TFL, the temperature below which Fermi liquid behavior is recovered, suggesting the presence of a quantum critical point (QCP) under pressure. However, while there is little change in the Yb valence of Yb2Ni12P7 up to 30 GPa, there is a strong increase for Yb2Ni12As7 under pressure, before a near constant value is reached. These results indicate that any magnetic QCP in this system is well separated from strong valence fluctuations. The pressure dependence of the valence and lattice parameters of Yb2Ni12As7 are compared and at 1 GPa, there is an anomaly in the unit cell volume as well as a change in the slope of the Yb valence, indicating a correlation between structural and electronic changes. PMID:26626431

  5. Crossover from a heavy fermion to intermediate valence state in noncentrosymmetric Yb2Ni12(P,As)7

    PubMed Central

    Jiang, W. B.; Yang, L.; Guo, C. Y.; Hu, Z.; Lee, J. M.; Smidman, M.; Wang, Y. F.; Shang, T.; Cheng, Z. W.; Gao, F.; Ishii, H.; Tsuei, K. D.; Liao, Y. F.; Lu, X.; Tjeng, L. H.; Chen, J. M.; Yuan, H. Q.

    2015-01-01

    We report measurements of the physical properties and electronic structure of the hexagonal compounds Yb2Ni12Pn7 (Pn = P, As) by measuring the electrical resistivity, magnetization, specific heat and partial fluorescence yield x-ray absorption spectroscopy (PFY-XAS). These demonstrate a crossover upon reducing the unit cell volume, from an intermediate valence state in Yb2Ni12As7 to a heavy-fermion paramagnetic state in Yb2Ni12P7, where the Yb is nearly trivalent. Application of pressure to Yb2Ni12P7 suppresses TFL, the temperature below which Fermi liquid behavior is recovered, suggesting the presence of a quantum critical point (QCP) under pressure. However, while there is little change in the Yb valence of Yb2Ni12P7 up to 30 GPa, there is a strong increase for Yb2Ni12As7 under pressure, before a near constant value is reached. These results indicate that any magnetic QCP in this system is well separated from strong valence fluctuations. The pressure dependence of the valence and lattice parameters of Yb2Ni12As7 are compared and at 1 GPa, there is an anomaly in the unit cell volume as well as a change in the slope of the Yb valence, indicating a correlation between structural and electronic changes. PMID:26626431

  6. Detection of excited-state electron bubbles in superfluid helium.

    PubMed

    Konstantinov, Denis; Maris, Humphrey J

    2003-01-17

    We report on experiments in which the pressure oscillation associated with a sound wave is used to explode electron bubbles in liquid helium. Using this technique, we are able to detect the presence of electron bubbles in excited states. PMID:12570553

  7. REFLECTIONS ON THE TWO-STATE ELECTRON TRANSFER MODEL.

    SciTech Connect

    Brunschwig, B.S.

    2000-01-12

    There is general agreement that the two most important factors determining electron transfer rates in solution are the degree of electronic interaction between the donor and acceptor sites, and the changes in the nuclear configurations of the donor, acceptor, and surrounding medium that occur upon the gain or loss of an electron Ll-51. The electronic interaction of the sites will be very weak, and the electron transfer slow, when the sites are far apart or their interaction is symmetry or spin forbidden. Since electron motion is much faster than nuclear motion, energy conservation requires that, prior to the actual electron transfer, the nuclear configurations of the reactants and the surrounding medium adjust from their equilibrium values to a configuration (generally) intermediate between that of the reactants and products. In the case of electron transfer between , two metal complexes in a polar solvent, the nuclear configuration changes involve adjustments in the metal-ligand and intraligand bond lengths and angles, and changes in the orientations of the surrounding solvent molecules. In common with ordinary chemical reactions, an electron transfer reaction can then be described in terms of the motion of the system on an energy surface from the reactant equilibrium configuration (initial state) to the product equilibrium configuration (final state) via the activated complex (transition state) configuration.

  8. Simultaneous measurement of electron and heavy particle temperatures in He laser-induced plasma by Thomson and Rayleigh scattering

    SciTech Connect

    Dzierzega, K.; Mendys, A.; Zawadzki, W.; Pokrzywka, B.; Pellerin, S.

    2013-04-01

    Thomson and Rayleigh scattering methods were applied to quantify the electron and heavy particle temperatures, as well as electron number density, in a laser spark in helium at atmospheric pressure. Plasma was created using 4.5 ns, 25 mJ pulses from Nd:YAG laser at 532 nm. Measurements, performed for the time interval between 20 ns and 800 ns after breakdown, show electron density and temperature to decrease from 7.8 Multiplication-Sign 10{sup 23} m{sup -3} to 2.6 Multiplication-Sign 10{sup 22} m{sup -3} and from 95 900 K to 10 350 K, respectively. At the same time, the heavy particle temperature drops from only 47 000 K down to 4100 K which indicates a two temperature plasma out of local isothermal equilibrium.

  9. An Automated Electronic Tongue for In-Situ Quick Monitoring of Trace Heavy Metals in Water Environment

    NASA Astrophysics Data System (ADS)

    Cai, Wei; Li, Yi; Gao, Xiaoming; Guo, Hongsun; Zhao, Huixin; Wang, Ping

    2009-05-01

    An automated electronic tongue instrumentation has been developed for in-situ concentration determination of trace heavy metals in water environment. The electronic tongue contains two main parts. The sensor part consists of a silicon-based Hg-coated Au microelectrodes array (MEA) for the detection of Zn(II), Cd(II), Pb(II) and Cu(II) and a multiple light-addressable potentiometric sensor (MLAPS) for the detection of Fe(III) and Cr(VI). The control part employs pumps, valves and tubes to enable the pick-up and pretreatment of aqueous sample. The electronic tongue realized detection of the six metals mentioned above at part-per-billion (ppb) level without manual operation. This instrumentation will have wide application in quick monitoring and prediction the heavy metal pollution in lakes and oceans.

  10. Surface-electronic-state effects in electron emission from the Be(0001) surface

    SciTech Connect

    Archubi, C. D.; Gravielle, M. S.; Silkin, V. M.

    2011-07-15

    We study the electron emission produced by swift protons impinging grazingly on a Be(0001) surface. The process is described within a collisional formalism using the band-structure-based (BSB) approximation to represent the electron-surface interaction. The BSB model provides an accurate description of the electronic band structure of the solid and the surface-induced potential. Within this approach we derive both bulk and surface electronic states, with these latter characterized by a strong localization at the crystal surface. We found that such surface electronic states play an important role in double-differential energy- and angle-resolved electron emission probabilities, producing noticeable structures in the electron emission spectra.

  11. Hidden beauty baryon states in the local hidden gauge approach with heavy quark spin symmetry

    NASA Astrophysics Data System (ADS)

    Xiao, C. W.; Oset, E.

    2013-11-01

    Using a coupled-channel unitary approach, combining the heavy quark spin symmetry and the dynamics of the local hidden gauge, we investigate the meson-baryon interaction with hidden beauty and obtain several new states of N around 11 GeV. We consider the basis of states η b N, ϒN, BΛ b , BΣ b , B * Λ b , B * Σ b , B * Σ {/b *} and find four basic bound states which correspond to BΣ b , BΣ {/b *}, B * Σ b and B * Σ {/b *}, decaying mostly into η b N and ϒN and with a binding energy about 50-130 MeV with respect to the thresholds of the corresponding channel. All of them have isospin I = 1/2 , and we find no bound states or resonances in I = 3/2 . The BΣ b state appears in J = 1/2 , the BΣ {/b *} in J = 3/2 , the B * Σ b appears nearly degenerate in J = 1/2 , 3/2 and the B * Σ {/b *} appears nearly degenerate in J = 1/2 , 3/2, 5/2. These states have a width from 2-110 MeV, with conservative estimates of uncertainties, except for the one in J = 5/2 which has zero width since it cannot decay into any of the states of the basis chosen. We make generous estimates of the uncertainties and find that within very large margins these states appear bound.

  12. Electric-Field-Induced Dissociation of Heavy Rydberg Ion-Pair States

    SciTech Connect

    Reinhold, Carlos O; Yoshida, S.; Dunning, F. B.

    2011-01-01

    A classical trajectory Monte Carlo approach is used to simulate the dissociation of H+..F and K+..Cl heavy Rydberg ion pairs induced by a ramped electric-field, a technique used experimentally to detect and probe ion-pair states. The simulations include the effects of the strong short-range repulsive interaction associated with ion-pair scattering and provide results in good agreement with experimental data for Stark wavepackets probed by a ramped field, demonstrating that many of the characteristics of field-induced dissociation can be well described using a purely classical model. The data also show that states with a given value of principal quantum number (i.e., binding energy) can dissociate over a broad range of applied fields, the exact field being governed by the initial orbital angular momentum and orientation of the state.

  13. Equation of state of hot polarized nuclear matter and heavy-ion fusion reactions

    SciTech Connect

    Ghodsi, O. N.; Gharaei, R.

    2011-08-15

    We employ the equation of state of hot polarized nuclear matter to simulate the repulsive force caused by the incompressibility effects of nuclear matter in the fusion reactions of heavy colliding ions. The results of our studies reveal that temperature effects of compound nuclei have significant importance in simulating the repulsive force on the fusion reactions for which the temperature of the compound nucleus increases up to about 2 MeV. Since the equation of state of hot nuclear matter depends upon the density and temperature of the nuclear matter, it has been suggested that, by using this equation of state, one can simulate simultaneously both the effects of the precompound nucleons' emission and the incompressibility of nuclear matter to calculate the nuclear potential in fusion reactions within a static formalism such as the double-folding (DF) model.

  14. Charge state and stopping dynamics of fast heavy ions in dense matter

    SciTech Connect

    Rosmej, O. N.; Blazevic, A.; Korostiy, S.; Bock, R.; Hoffmann, D. H. H.; Pikuz, S. A. Jr.; Efremov, V. P.; Fortov, V. E.; Fertman, A.; Mutin, T.; Pikuz, T. A.; Faenov, A. Ya.

    2005-11-15

    K-shell radiation of fast heavy ions penetrating solid matter was used to analyze the stopping dynamics of ions over more than 80% of the stopping path. The most important advantage of this method is that the data is obtained with a high spatial resolution directly from the interaction volume. In experiments 11.4 MeV/u Ca projectile were slowed down in solid quartz and low-density SiO{sub 2} aerogel targets. Characteristic projectile and target spectra in the photon energy range of 1.5-4 keV were registered by means of spherically bent crystal spectrometers with high spectral and spatial resolution in the direction of the ion beam propagation. K-shell spectra of heavy ions induced by close collisions with target atoms provided information about the projectile charge state and velocity dynamics. The line intensity distribution of the K-shell transitions arising from ions with different ion charges represents the charge state distribution along the ion beam track. The variation of the line Doppler shift due to the ion deceleration in the target material was used to determine the ion velocity dynamics. The spectroscopic analysis of the stopping process was complemented by measurements of the energy loss and ion charge state distribution after the ion beam emerged from the target using a standard time-of-flight method and magnet spectrometer.

  15. Electron-positron pairs in physics and astrophysics: From heavy nuclei to black holes

    NASA Astrophysics Data System (ADS)

    Ruffini, Remo; Vereshchagin, Gregory; Xue, She-Sheng

    2010-02-01

    Due to the interaction of physics and astrophysics we are witnessing in these years a splendid synthesis of theoretical, experimental and observational results originating from three fundamental physical processes. They were originally proposed by Dirac, by Breit and Wheeler and by Sauter, Heisenberg, Euler and Schwinger. For almost seventy years they have all three been followed by a continued effort of experimental verification on Earth-based experiments. The Dirac process, e+e-→2γ, has been by far the most successful. It has obtained extremely accurate experimental verification and has led as well to an enormous number of new physics in possibly one of the most fruitful experimental avenues by introduction of storage rings in Frascati and followed by the largest accelerators worldwide: DESY, SLAC etc. The Breit-Wheeler process, 2γ→e+e-, although conceptually simple, being the inverse process of the Dirac one, has been by far one of the most difficult to be verified experimentally. Only recently, through the technology based on free electron X-ray laser and its numerous applications in Earth-based experiments, some first indications of its possible verification have been reached. The vacuum polarization process in strong electromagnetic field, pioneered by Sauter, Heisenberg, Euler and Schwinger, introduced the concept of critical electric field Ec=me2c3/(eħ). It has been searched without success for more than forty years by heavy-ion collisions in many of the leading particle accelerators worldwide. The novel situation today is that these same processes can be studied on a much more grandiose scale during the gravitational collapse leading to the formation of a black hole being observed in Gamma Ray Bursts (GRBs). This report is dedicated to the scientific race. The theoretical and experimental work developed in Earth-based laboratories is confronted with the theoretical interpretation of space-based observations of phenomena originating on cosmological

  16. Molecular electronics with single molecules in solid-state devices.

    PubMed

    Moth-Poulsen, Kasper; Bjørnholm, Thomas

    2009-09-01

    The ultimate aim of molecular electronics is to understand and master single-molecule devices. Based on the latest results on electron transport in single molecules in solid-state devices, we focus here on new insights into the influence of metal electrodes on the energy spectrum of the molecule, and on how the electron transport properties of the molecule depend on the strength of the electronic coupling between it and the electrodes. A variety of phenomena are observed depending on whether this coupling is weak, intermediate or strong. PMID:19734925

  17. Multi-pair states in electron-positron pair creation

    NASA Astrophysics Data System (ADS)

    Wöllert, Anton; Bauke, Heiko; Keitel, Christoph H.

    2016-09-01

    Ultra strong electromagnetic fields can lead to spontaneous creation of single or multiple electron-positron pairs. A quantum field theoretical treatment of the pair creation process combined with numerical methods provides a description of the fermionic quantum field state, from which all observables of the multiple electron-positron pairs can be inferred. This allows to study the complex multi-particle dynamics of electron-positron pair creation in-depth, including multi-pair statistics as well as momentum distributions and spin. To illustrate the potential benefit of this approach, it is applied to the intermediate regime of pair creation between nonperturbative Schwinger pair creation and perturbative multiphoton pair creation where the creation of multi-pair states becomes nonnegligible but cascades do not yet set in. Furthermore, it is demonstrated how spin and helicity of the created electrons and positrons are affected by the polarization of the counterpropagating laser fields, which induce the creation of electron-positron pairs.

  18. Super-heavy electron material as metallic refrigerant for adiabatic demagnetization cooling

    PubMed Central

    Tokiwa, Yoshifumi; Piening, Boy; Jeevan, Hirale S.; Bud’ko, Sergey L.; Canfield, Paul C.; Gegenwart, Philipp

    2016-01-01

    Low-temperature refrigeration is of crucial importance in fundamental research of condensed matter physics, because the investigations of fascinating quantum phenomena, such as superconductivity, superfluidity, and quantum criticality, often require refrigeration down to very low temperatures. Currently, cryogenic refrigerators with 3He gas are widely used for cooling below 1 K. However, usage of the gas has been increasingly difficult because of the current worldwide shortage. Therefore, it is important to consider alternative methods of refrigeration. We show that a new type of refrigerant, the super-heavy electron metal YbCo2Zn20, can be used for adiabatic demagnetization refrigeration, which does not require 3He gas. This method has a number of advantages, including much better metallic thermal conductivity compared to the conventional insulating refrigerants. We also demonstrate that the cooling performance is optimized in Yb1−xScxCo2Zn20 by partial Sc substitution, with x ~ 0.19. The substitution induces chemical pressure that drives the materials to a zero-field quantum critical point. This leads to an additional enhancement of the magnetocaloric effect in low fields and low temperatures, enabling final temperatures well below 100 mK. This performance has, up to now, been restricted to insulators. For nearly a century, the same principle of using local magnetic moments has been applied for adiabatic demagnetization cooling. This study opens new possibilities of using itinerant magnetic moments for cryogen-free refrigeration. PMID:27626073

  19. Super-heavy electron material as metallic refrigerant for adiabatic demagnetization cooling.

    PubMed

    Tokiwa, Yoshifumi; Piening, Boy; Jeevan, Hirale S; Bud'ko, Sergey L; Canfield, Paul C; Gegenwart, Philipp

    2016-09-01

    Low-temperature refrigeration is of crucial importance in fundamental research of condensed matter physics, because the investigations of fascinating quantum phenomena, such as superconductivity, superfluidity, and quantum criticality, often require refrigeration down to very low temperatures. Currently, cryogenic refrigerators with (3)He gas are widely used for cooling below 1 K. However, usage of the gas has been increasingly difficult because of the current worldwide shortage. Therefore, it is important to consider alternative methods of refrigeration. We show that a new type of refrigerant, the super-heavy electron metal YbCo2Zn20, can be used for adiabatic demagnetization refrigeration, which does not require (3)He gas. This method has a number of advantages, including much better metallic thermal conductivity compared to the conventional insulating refrigerants. We also demonstrate that the cooling performance is optimized in Yb1-x Sc x Co2Zn20 by partial Sc substitution, with x ~ 0.19. The substitution induces chemical pressure that drives the materials to a zero-field quantum critical point. This leads to an additional enhancement of the magnetocaloric effect in low fields and low temperatures, enabling final temperatures well below 100 mK. This performance has, up to now, been restricted to insulators. For nearly a century, the same principle of using local magnetic moments has been applied for adiabatic demagnetization cooling. This study opens new possibilities of using itinerant magnetic moments for cryogen-free refrigeration. PMID:27626073

  20. Tunable topological states in electron-doped HTT-Pt

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoming; Wang, Zhenhai; Zhao, Mingwen; Liu, Feng

    2016-04-01

    Modulating topologically nontrivial states in trivial materials is of both scientific and technological interest. Using first-principles calculations, we propose a demonstration of electron-doping- (or gate-voltage-) induced multiple quantum states; namely, quantum spin Hall (QSH) and quantum anomalous Hall (QAH) states, in a single material of the organometallic framework (HTT-Pt) synthesized from triphenylene hexathiol molecules (HTT) and PtC l2 . At a low doping level, the trivial HTT-Pt converts to a QSH insulator protected by time-reversal symmetry (TRS). When the electronic doping concentration is further increased, TRS will be broken, making the HTT-Pt a QAH insulator. The band gaps of these topologically nontrivial states can be as large as 42.5 meV, suggesting robustness at high temperatures. The possibility of switching between the QSH and QAH states offers an intriguing platform for a different device paradigm by interfacing between QSH and QAH states.

  1. Fast electronic resistance switching involving hidden charge density wave states

    PubMed Central

    Vaskivskyi, I.; Mihailovic, I. A.; Brazovskii, S.; Gospodaric, J.; Mertelj, T.; Svetin, D.; Sutar, P.; Mihailovic, D.

    2016-01-01

    The functionality of computer memory elements is currently based on multi-stability, driven either by locally manipulating the density of electrons in transistors or by switching magnetic or ferroelectric order. Another possibility is switching between metallic and insulating phases by the motion of ions, but their speed is limited by slow nucleation and inhomogeneous percolative growth. Here we demonstrate fast resistance switching in a charge density wave system caused by pulsed current injection. As a charge pulse travels through the material, it converts a commensurately ordered polaronic Mott insulating state in 1T–TaS2 to a metastable electronic state with textured domain walls, accompanied with a conversion of polarons to band states, and concurrent rapid switching from an insulator to a metal. The large resistance change, high switching speed (30 ps) and ultralow energy per bit opens the way to new concepts in non-volatile memory devices manipulating all-electronic states. PMID:27181483

  2. Fast electronic resistance switching involving hidden charge density wave states

    NASA Astrophysics Data System (ADS)

    Vaskivskyi, I.; Mihailovic, I. A.; Brazovskii, S.; Gospodaric, J.; Mertelj, T.; Svetin, D.; Sutar, P.; Mihailovic, D.

    2016-05-01

    The functionality of computer memory elements is currently based on multi-stability, driven either by locally manipulating the density of electrons in transistors or by switching magnetic or ferroelectric order. Another possibility is switching between metallic and insulating phases by the motion of ions, but their speed is limited by slow nucleation and inhomogeneous percolative growth. Here we demonstrate fast resistance switching in a charge density wave system caused by pulsed current injection. As a charge pulse travels through the material, it converts a commensurately ordered polaronic Mott insulating state in 1T-TaS2 to a metastable electronic state with textured domain walls, accompanied with a conversion of polarons to band states, and concurrent rapid switching from an insulator to a metal. The large resistance change, high switching speed (30 ps) and ultralow energy per bit opens the way to new concepts in non-volatile memory devices manipulating all-electronic states.

  3. Fast electronic resistance switching involving hidden charge density wave states.

    PubMed

    Vaskivskyi, I; Mihailovic, I A; Brazovskii, S; Gospodaric, J; Mertelj, T; Svetin, D; Sutar, P; Mihailovic, D

    2016-01-01

    The functionality of computer memory elements is currently based on multi-stability, driven either by locally manipulating the density of electrons in transistors or by switching magnetic or ferroelectric order. Another possibility is switching between metallic and insulating phases by the motion of ions, but their speed is limited by slow nucleation and inhomogeneous percolative growth. Here we demonstrate fast resistance switching in a charge density wave system caused by pulsed current injection. As a charge pulse travels through the material, it converts a commensurately ordered polaronic Mott insulating state in 1T-TaS2 to a metastable electronic state with textured domain walls, accompanied with a conversion of polarons to band states, and concurrent rapid switching from an insulator to a metal. The large resistance change, high switching speed (30 ps) and ultralow energy per bit opens the way to new concepts in non-volatile memory devices manipulating all-electronic states. PMID:27181483

  4. Electronic Ground and Excited State Spectral Diffusion of a Photocatalyst

    NASA Astrophysics Data System (ADS)

    Kiefer, Laura M.; King, John T.; Kubarych, Kevin J.

    2014-06-01

    Re(bpy)(CO)_3Cl is a well studied CO_2 reduction catalyst, known for its ability as both a photosensitizer and a catalyst with a high quantum yield and product selectivity. The catalysis reaction is initiated by a 400 nm excitation, followed by an intersystem crossing (ISC) and re-equilibration in the lowest triplet state. We utilize the quasi-equilibrium nature of this long-lived triplet metal-to-ligand charge-transfer (3MLCT) state to completely characterize the solvent dynamics using the technique of transient two-dimensional infrared (t-2DIR) spectroscopy to extract observables such as the frequency-frequency correlation function (FFCF), an equilibrium function. The electronic ground state solvent dynamics are characterized using equilibrium two-dimensional infrared spectroscopy (2D IR). Our technique allows us to independently observe the solvent dynamics of different electronic states and compare them. In this study, three carbonyl stretching modes were utilized to probe both the intramolecular and solvent environments in each electronic state. In the electronic ground state, the totally symmetric mode exhibits pure homogeneous broadening and a lack of spectral dynamics, while the two other modes have similar FFCF decay times of ˜ 1.5 ps. In the 3MLCT, however, all three modes experience similar spectral dynamics and have a FFCF decay time of ˜ 4.5 ps, three times slower than in the electronic ground state. Our technique allows us to directly observe the differences in spectral dynamics of the ground and excited electronic states and allows us to attribute the differences to specific origins such as solvent-solute coupling and molecular flexibility.

  5. Two-electron states and state exchange time control in parabolic quantum dot

    NASA Astrophysics Data System (ADS)

    Baghdasaryan, D. A.; Kazaryan, E. M.; Sarkisyan, H. A.

    2014-04-01

    Using the Heisenberg uncertainty relationship and the stationary perturbation theory we consider two-electron states in a spherically symmetric parabolic quantum dot (parabolic helium atom). The dependence of ground-state energy on the QD size is studied. The energy of two-electron system monotonically decreases with QD radius increase. The problem of the state exchange time control in QD is discussed, taking into account the spins of the electrons in the Russell-Saunders approximation. With the increase of the QD radius the state exchange time increases.

  6. Electron momentum spectroscopy of aniline taking account of nuclear dynamics in the initial electronic ground state

    NASA Astrophysics Data System (ADS)

    Farasat, M.; Shojaei, S. H. R.; Morini, F.; Golzan, M. M.; Deleuze, M. S.

    2016-04-01

    The electronic structure, electron binding energy spectrum and (e, 2e) momentum distributions of aniline have been theoretically predicted at an electron impact energy of 1.500 keV on the basis of Born-Oppenheimer molecular dynamical simulations, in order to account for thermally induced nuclear motions in the initial electronic ground state. Most computed momentum profiles are rather insensitive to thermally induced alterations of the molecular structure, with the exception of the profiles corresponding to two ionization bands at electron binding energies comprised between ˜10.0 and ˜12.0 eV (band C) and between ˜16.5 and ˜20.0 eV (band G). These profiles are found to be strongly influenced by nuclear dynamics in the electronic ground state, especially in the low momentum region. The obtained results show that thermal averaging smears out most generally the spectral fingerprints that are induced by nitrogen inversion.

  7. Alternative ground states enable pathway switching in biological electron transfer

    PubMed Central

    Abriata, Luciano A.; Álvarez-Paggi, Damián; Ledesma, Gabriela N.; Blackburn, Ninian J.; Vila, Alejandro J.; Murgida, Daniel H.

    2012-01-01

    Electron transfer is the simplest chemical reaction and constitutes the basis of a large variety of biological processes, such as photosynthesis and cellular respiration. Nature has evolved specific proteins and cofactors for these functions. The mechanisms optimizing biological electron transfer have been matter of intense debate, such as the role of the protein milieu between donor and acceptor sites. Here we propose a mechanism regulating long-range electron transfer in proteins. Specifically, we report a spectroscopic, electrochemical, and theoretical study on WT and single-mutant CuA redox centers from Thermus thermophilus, which shows that thermal fluctuations may populate two alternative ground-state electronic wave functions optimized for electron entry and exit, respectively, through two different and nearly perpendicular pathways. These findings suggest a unique role for alternative or “invisible” electronic ground states in directional electron transfer. Moreover, it is shown that this energy gap and, therefore, the equilibrium between ground states can be fine-tuned by minor perturbations, suggesting alternative ways through which protein–protein interactions and membrane potential may optimize and regulate electron–proton energy transduction. PMID:23054836

  8. Integrating proton coupled electron transfer (PCET) and excited states

    SciTech Connect

    Gagliardi, Christopher J.; Westlake, Brittany C.; Kent, Caleb A.; Paul, Jared J.; Papanikolas, John M.; Meyer, Thomas J.

    2010-11-01

    In many of the chemical steps in photosynthesis and artificial photosynthesis, proton coupled electron transfer (PCET) plays an essential role. An important issue is how excited state reactivity can be integrated with PCET to carry out solar fuel reactions such as water splitting into hydrogen and oxygen or water reduction of CO2 to methanol or hydrocarbons. The principles behind PCET and concerted electron–proton transfer (EPT) pathways are reasonably well understood. In Photosystem II antenna light absorption is followed by sensitization of chlorophyll P680 and electron transfer quenching to give P680+. The oxidized chlorophyll activates the oxygen evolving complex (OEC), a CaMn4 cluster, through an intervening tyrosine–histidine pair, YZ. EPT plays a major role in a series of four activation steps that ultimately result in loss of 4e-/4H+ from the OEC with oxygen evolution. The key elements in photosynthesis and artificial photosynthesis – light absorption, excited state energy and electron transfer, electron transfer activation of multiple-electron, multiple-proton catalysis – can also be assembled in dye sensitized photoelectrochemical synthesis cells (DS-PEC). In this approach, molecular or nanoscale assemblies are incorporated at separate electrodes for coupled, light driven oxidation and reduction. Separate excited state electron transfer followed by proton transfer can be combined in single semi-concerted steps (photo-EPT) by photolysis of organic charge transfer excited states with H-bonded bases or in metal-to-ligand charge transfer (MLCT) excited states in pre-associated assemblies with H-bonded electron transfer donors or acceptors. In these assemblies, photochemically induced electron and proton transfer occur in a single, semi-concerted event to give high-energy, redox active intermediates.

  9. Effects of different additives with assistance of microwave heating for heavy metal stabilization in electronic industry sludge.

    PubMed

    Jothiramalingam, R; Lo, Shang-Lien; Chen, Ching-lung

    2010-01-01

    Electronic industrial wastewater sludge in Taiwan is normally passed through an acid-extraction process to reclaim most of the copper ions, the remaining residue may still need to be treated by various stabilization technologies using suitable additives. Cement solidification is used as the common method to stabilize the industrial wastewater sludge in Taiwan. However, this method has the disadvantage of an increase in waste volume. In the present study selective additives such as sodium sulfide, barium manganate and different phase of alumina were tested as a possible alternate additive to stabilize the heavy metal ion in the treated solid waste sludge via microwave heating treatment. The effects of additive amount, power of microwave irradiation and reaction time have been studied. Heavy metal leaching capacity is determined by using standard toxicity characteristic leaching procedure test and elemental content in the leachate is analyzed by inductively coupled plasma analysis. Sodium sulfide is effectively stabilizing the leaching copper ion with high selectivity in the presence of microwave irradiation and finally stabilized in the form of copper sulfide, which is a significant reaction to stabilize the copper ion leaching in the waste sludge. Complete stabilization of heavy metal ion and copper ion content (<5mgL(-1)) in industrial sludge is achieved by heating the microwave treated barium manganate and alumina additives by adopting suitable reaction conditions. Hybrid microwave and conventional heating process with minor amount of additive providing the efficient heavy metal stabilization for treated electronic industry waste sludge. PMID:19945139

  10. Quantum electrodynamic corrections for the valence shell in heavy many-electron atoms

    SciTech Connect

    Thierfelder, C.; Schwerdtfeger, P.

    2010-12-15

    We present quantum electrodynamic (QED) calculations within the picture of bound-state QED for the frequency-dependent Breit interaction between electrons, the vacuum polarization, and the electron self-energy correction starting from the Dirac-Coulomb Hamiltonian for the ionization potentials of the group 1, 2, 11, 12, 13, and 18 elements of the periodic table, and down to the superheavy elements up to nuclear charge Z=120. The results for the s-block elements are in very good agreement with earlier studies by Labzowsky et al. [Phys. Rev. A 59, 2707 (1999)]. We discuss the influence of the variational versus perturbative treatment of the Breit interaction for valence-space ionization potentials. We argue that the lowest-order QED contributions become as important as the Breit interaction for ionization potentials out of the valence s shell.

  11. Quantum electrodynamic corrections for the valence shell in heavy many-electron atoms

    NASA Astrophysics Data System (ADS)

    Thierfelder, C.; Schwerdtfeger, P.

    2010-12-01

    We present quantum electrodynamic (QED) calculations within the picture of bound-state QED for the frequency-dependent Breit interaction between electrons, the vacuum polarization, and the electron self-energy correction starting from the Dirac-Coulomb Hamiltonian for the ionization potentials of the group 1, 2, 11, 12, 13, and 18 elements of the periodic table, and down to the superheavy elements up to nuclear charge Z=120. The results for the s-block elements are in very good agreement with earlier studies by Labzowsky [Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.59.2707 59, 2707 (1999)]. We discuss the influence of the variational versus perturbative treatment of the Breit interaction for valence-space ionization potentials. We argue that the lowest-order QED contributions become as important as the Breit interaction for ionization potentials out of the valence s shell.

  12. Computing electronic structures: A new multiconfiguration approach for excited states

    SciTech Connect

    Cances, Eric . E-mail: cances@cermics.enpc.fr; Galicher, Herve . E-mail: galicher@cermics.enpc.fr; Lewin, Mathieu . E-mail: lewin@cermic.enpc.fr

    2006-02-10

    We present a new method for the computation of electronic excited states of molecular systems. This method is based upon a recent theoretical definition of multiconfiguration excited states [due to one of us, see M. Lewin, Solutions of the multiconfiguration equations in quantum chemistry, Arch. Rat. Mech. Anal. 171 (2004) 83-114]. Our algorithm, dedicated to the computation of the first excited state, always converges to a stationary state of the multiconfiguration model, which can be interpreted as an approximate excited state of the molecule. The definition of this approximate excited state is variational. An interesting feature is that it satisfies a non-linear Hylleraas-Undheim-MacDonald type principle: the energy of the approximate excited state is an upper bound to the true excited state energy of the N-body Hamiltonian. To compute the first excited state, one has to deform paths on a manifold, like this is usually done in the search for transition states between reactants and products on potential energy surfaces. We propose here a general method for the deformation of paths which could also be useful in other settings. We also compare our method to other approaches used in Quantum Chemistry and give some explanation of the unsatisfactory behaviours which are sometimes observed when using the latter. Numerical results for the special case of two-electron systems are provided: we compute the first singlet excited state potential energy surface of the H {sub 2} molecule.

  13. Electron delocalization and electron density of small polycyclic aromatic hydrocarbons in singlet excited states.

    PubMed

    Estévez-Fregoso, Mar; Hernández-Trujillo, Jesús

    2016-04-28

    The four lowest singlet electronic states of benzene, the acenes from naphthalene to pentacene, phenanthrene and pyrene were studied by means of theoretical methods. Their vertical excitation energies from the ground electronic states were computed at the CASPT2 approximation. As an attempt to explain the trends observed in the excitation energies, several descriptors based on the electron density were used and the similarity of these molecules with their ground state counterparts was analyzed. It was found that the changes of the topological properties at the C-C bond critical points do not explain the decreasing trends for the excitation energies with the increase of the number of rings, in part because the small changes that take place in the electron density occur above and below the molecular plane. A similarity index based on electron delocalization between quantum topological atoms was defined to compare a molecule in two different electronic states. It was found that, mainly for the acenes, this index goes in line with the excitation energies to the first excited state. Implications of the changes in electron delocalization on the aromatic character of these molecules are also discussed. In general, local aromaticity decreases upon excitation. PMID:26795361

  14. Magnetism and superconductivity driven by identical 4f states in a heavy-fermion metal

    SciTech Connect

    Thompson, Joe E; Nair, S; Stockert, O; Witte, U; Nicklas, M; Schedler, R; Bianchi, A; Fisk, Z; Wirth, S; Steglich, K

    2009-01-01

    The apparently inimical relationship between magnetism and superconductivity has come under increasing scrutiny in a wide range of material classes, where the free energy landscape conspires to bring them in close proximity to each other. Particularly enigmatic is the case when these phases microscopically interpenetrate, though the manner in which this can be accomplished remains to be fully comprehended. Here, we present combined measurements of elastic neutron scattering, magnetotransport, and heat capacity on a prototypical heavy fermion system, in which antiferromagnetism and superconductivity are observed. Monitoring the response of these states to the presence of the other, as well as to external thermal and magnetic perturbations, points to the possibility that they emerge from different parts of the Fermi surface. Therefore, a single 4f state could be both localized and itinerant, thus accounting for the coexistence of magnetism and superconductivity.

  15. Trapping Image State Electrons on Graphene Layers and Islands

    NASA Astrophysics Data System (ADS)

    Dadap, Jerry; Niesner, Daniel; Fauster, Thomas; Zaki, Nader; Knox, Kevin; Yeh, Po-Chi; Bhandari, Rohan; Osgood, Richard M.; Petrovic, Marin; Kralj, Marko

    2012-02-01

    The understanding of graphene-metal interfaces is of utmost importance in graphene transport phenomena. To probe this interface we use time- and angle-resolved two-photon photoemission to map the bound, unoccupied electronic structure of the weakly coupled graphene/Ir(111) system. The energy, dispersion, and lifetime of the lowest three image-potential states are measured. In addition, the weak interaction between Ir and the smooth, epitaxial graphene permits observation of resonant transitions from an unquenched Shockley-type surface state of the Ir substrate to graphene/Ir image-potential states. The image-potential-state lifetimes are comparable to those of mid-gap clean metal surfaces. Evidence of localization of the excited image-state electrons on single-atom-layer graphene islands is provided by coverage-dependent measurements.

  16. Photoionization of furan from the ground and excited electronic states

    NASA Astrophysics Data System (ADS)

    Ponzi, Aurora; Sapunar, Marin; Angeli, Celestino; Cimiraglia, Renzo; Došlić, Nada; Decleva, Piero

    2016-02-01

    Here we present a comparative computational study of the photoionization of furan from the ground and the two lowest-lying excited electronic states. The study aims to assess the quality of the computational methods currently employed for treating bound and continuum states in photoionization. For the ionization from the ground electronic state, we show that the Dyson orbital approach combined with an accurate solution of the continuum one particle wave functions in a multicenter B-spline basis, at the density functional theory (DFT) level, provides cross sections and asymmetry parameters in excellent agreement with experimental data. On the contrary, when the Dyson orbitals approach is combined with the Coulomb and orthogonalized Coulomb treatments of the continuum, the results are qualitatively different. In excited electronic states, three electronic structure methods, TDDFT, ADC(2), and CASSCF, have been used for the computation of the Dyson orbitals, while the continuum was treated at the B-spline/DFT level. We show that photoionization observables are sensitive probes of the nature of the excited states as well as of the quality of excited state wave functions. This paves the way for applications in more complex situations such as time resolved photoionization spectroscopy.

  17. On the correct electronic ground state of Tc( g )

    SciTech Connect

    Rard, J.A. ); Rand, M.H. ); Thornback, J.R. ); Wanner, H. )

    1991-05-01

    The electronic ground state of Tc({ital g}) is {sup 6}{ital S}{sub 5/2}, which arises from a 4{ital d}{sup 5}5{ital s}{sup 2} valence electron configuration. However, there are several treatises and review articles in which the ground state is incorrectly given as {ital S}{sub 9/2} with a valence electron configuration of 4{ital d}{sup 6}5{ital s}{sup 1}. The origin of this incorrect assignment was traced to the misinterpretation of a paper on the hyperfine splitting of the optical spectrum of technetium, and to confusion between nuclear and electronic spins.

  18. Confined electronic states and their modulations in graphene nanorings

    NASA Astrophysics Data System (ADS)

    Zhu, Jia-Lin; Wang, Xingyuan; Yang, Ning

    2012-09-01

    Confined electronic states in quantum rings formed by spatially modulated finite Dirac gap (FDGQR) in graphene are systematically studied by series-expansion method, and are compared with those in infinite-mass-boundary and one-dimensional quantum rings. The shape-size effect of FDGQR is illustrated to be distinct from that in graphene quantum dots. The Aharonov-Bohm effect in FDGQR is clearly shown by the energy spectrum and the optical-transition probabilities. The FDGQR coupled with the electrostatic-potential induced nanoring is found useful for modulating the Dirac electronic states and the optical-transition probabilities. These results may help us to understand and to control the quantum behaviors of confined electronic states in graphene.

  19. Fragmentation pathwaysfor selected electronic states of theacetylene dication

    SciTech Connect

    Osipov, Timur; Rescigno, Thomas N.; Weber, Thorsten; Miyabe,Shungo; Jahnke, T.; Alnaser, A.; Hertlein, Markus P.; Jagutzki, O.; Schmidt, L.Ph.H.; Schoffler, M.; Foucar, L.; Schossler, S.; Havermeier,T.; Odenweller,M.; Voss, S.; Feinberg, Ben; Landers, Alan; Prior, MichaelH.; Dorner, Reinhart; Cocke, C.L.; Belkacem, Ali

    2007-12-18

    Coincident measurement of the Auger electron and fragmention momenta emitted after carbon core-level photoionization of acetylenehas yielded new understanding of how the dication fragments. Ab initiocalculations and experimental data, including body-frame Auger angulardistributions, are used to identify the parent electronic states andtogether yield a comprehensive map of the dissociation pathways whichinclude surface crossings and barriers to direct dissociation. The Augerangular distributions show evidence of core-holelocalization.

  20. TOPICAL REVIEW Electronic states of graphene nanoribbons and analytical solutions

    NASA Astrophysics Data System (ADS)

    Wakabayashi, Katsunori; Sasaki, Ken-ichi; Nakanishi, Takeshi; Enoki, Toshiaki

    2010-10-01

    Graphene is a one-atom-thick layer of graphite, where low-energy electronic states are described by the massless Dirac fermion. The orientation of the graphene edge determines the energy spectrum of π-electrons. For example, zigzag edges possess localized edge states with energies close to the Fermi level. In this review, we investigate nanoscale effects on the physical properties of graphene nanoribbons and clarify the role of edge boundaries. We also provide analytical solutions for electronic dispersion and the corresponding wavefunction in graphene nanoribbons with their detailed derivation using wave mechanics based on the tight-binding model. The energy band structures of armchair nanoribbons can be obtained by making the transverse wavenumber discrete, in accordance with the edge boundary condition, as in the case of carbon nanotubes. However, zigzag nanoribbons are not analogous to carbon nanotubes, because in zigzag nanoribbons the transverse wavenumber depends not only on the ribbon width but also on the longitudinal wavenumber. The quantization rule of electronic conductance as well as the magnetic instability of edge states due to the electron-electron interaction are briefly discussed.

  1. Predictive equation of state method for heavy materials based on the Dirac equation and density functional theory

    NASA Astrophysics Data System (ADS)

    Wills, John M.; Mattsson, Ann E.

    2012-02-01

    Density functional theory (DFT) provides a formally predictive base for equation of state properties. Available approximations to the exchange/correlation functional provide accurate predictions for many materials in the periodic table. For heavy materials however, DFT calculations, using available functionals, fail to provide quantitative predictions, and often fail to be even qualitative. This deficiency is due both to the lack of the appropriate confinement physics in the exchange/correlation functional and to approximations used to evaluate the underlying equations. In order to assess and develop accurate functionals, it is essential to eliminate all other sources of error. In this talk we describe an efficient first-principles electronic structure method based on the Dirac equation and compare the results obtained with this method with other methods generally used. Implications for high-pressure equation of state of relativistic materials are demonstrated in application to Ce and the light actinides. Sandia National Laboratories is a multi-program laboratory managed andoperated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  2. 78 FR 11804 - Approval and Promulgation of Implementation Plans; State of Kansas; Idle Reduction of Heavy-Duty...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-20

    ...EPA is proposing to approve the State Implementation Plan (SIP) submitted by the State of Kansas on July 27, 2010, to add two new rules which implement restrictions on the idling of heavy duty diesel vehicles and reduce nitrogen oxide (NOX) emissions at stationary sources in the Kansas portion of the Kansas City Maintenance Area for ozone. EPA is approving this revision because the......

  3. Two-electron photoionization of ground-state lithium

    SciTech Connect

    Kheifets, A. S.; Fursa, D. V.; Bray, I.

    2009-12-15

    We apply the convergent close-coupling (CCC) formalism to single-photon two-electron ionization of the lithium atom in its ground state. We treat this reaction as single-electron photon absorption followed by inelastic scattering of the photoelectron on a heliumlike Li{sup +} ion. The latter scattering process can be described accurately within the CCC formalism. We obtain integrated cross sections of single photoionization leading to the ground and various excited states of the Li{sup +} ion as well as double photoionization extending continuously from the threshold to the asymptotic limit of infinite photon energy. Comparison with available experimental and theoretical data validates the CCC model.

  4. Integral cross sections for electron impact excitation of vibrational and electronic states in phenol.

    PubMed

    Neves, R F C; Jones, D B; Lopes, M C A; Blanco, F; García, G; Ratnavelu, K; Brunger, M J

    2015-05-21

    We report on measurements of integral cross sections (ICSs) for electron impact excitation of a series of composite vibrational modes and electronic-states in phenol, where the energy range of those experiments was 15-250 eV. There are currently no other results against which we can directly compare those measured data. We also report results from our independent atom model with screened additivity rule correction computations, namely, for the inelastic ICS (all discrete electronic states and neutral dissociation) and the total ionisation ICS. In addition, for the relevant dipole-allowed excited electronic states, we also report f-scaled Born-level and energy-corrected and f-scaled Born-level (BEf-scaled) ICS. Where possible, our measured and calculated ICSs are compared against one another with the general level of accord between them being satisfactory to within the measurement uncertainties. PMID:26001459

  5. Integral cross sections for electron impact excitation of vibrational and electronic states in phenol

    SciTech Connect

    Neves, R. F. C.; Jones, D. B.; Lopes, M. C. A.; Blanco, F.; García, G.; Ratnavelu, K.; Brunger, M. J.

    2015-05-21

    We report on measurements of integral cross sections (ICSs) for electron impact excitation of a series of composite vibrational modes and electronic-states in phenol, where the energy range of those experiments was 15–250 eV. There are currently no other results against which we can directly compare those measured data. We also report results from our independent atom model with screened additivity rule correction computations, namely, for the inelastic ICS (all discrete electronic states and neutral dissociation) and the total ionisation ICS. In addition, for the relevant dipole-allowed excited electronic states, we also report f-scaled Born-level and energy-corrected and f-scaled Born-level (BEf-scaled) ICS. Where possible, our measured and calculated ICSs are compared against one another with the general level of accord between them being satisfactory to within the measurement uncertainties.

  6. Electron-impact excitation of the low-lying electronic states of formaldehyde

    NASA Technical Reports Server (NTRS)

    Chutjian, A.

    1974-01-01

    Electron-impact excitation has been observed at incident electron energies of 10.1 and 20.1 eV to the first five excited electronic states of formaldehyde lying at and below the 1B2 state at 7.10 eV. These excitations include two new transitions in the energy-loss range 5.6-6.2 eV and 6.7-7.0 eV which have been detected for the first time, either through electron-impact excitation or photon absorption. The differential cross sections of these new excitations are given at scattering angles between 15 and 135 deg. These cross-section ratios peak at large scattering angles - a characteristic of triplet - singlet excitations. The design and performance of the electron-impact spectrometer used in the above observations is outlined and discussed.

  7. Fate of the initial state perturbations in heavy ion collisions. II. Glauber fluctuations and sounds

    SciTech Connect

    Staig, Pilar; Shuryak, Edward

    2011-09-15

    Heavy-ion collisions at the BNL Relativistic Heavy Ion Collider (RHIC) are well described by the (nearly ideal) hydrodynamics for average events. In the present paper we study initial state fluctuations appearing on an event-by-event basis and the propagation of perturbations induced by them. We found that (i) fluctuations of several of the lowest harmonics have comparable magnitudes and (ii) that at least all odd harmonics are correlated in phase, (iii) thus indicating the local nature of fluctuations. We argue that such local perturbations should be the source of the ''tiny bang,'' a pulse of sound propagating from it. We identify its two fundamental scales as (i) the ''sound horizon'' (analogous to the absolute ruler in cosmic microwave background and galaxy distributions) and (ii) the ''viscous horizon'' separating damped and undamped harmonics. We then qualitatively describe how one can determine them from the data and thus determine two fundamental parameters of the matter: the (average) speed of sound and viscosity. The rest of the paper explains how one can study mutual coherence of various harmonics. For that, one should go beyond the two-particle correlations to three (or more) particles. Mutual coherence is important for the picture of propagating sound waves.

  8. Excitation energies of double isobar-analog states in heavy nuclei

    SciTech Connect

    Poplavskii, I. V.

    1988-12-01

    Several new relationships are established for isomultiplets on the basis of a theory in which the Coulomb coupling constant (CCC) is allowed to be complex. In particular, the following rule is formulated: the energies for fission or decay of members of an isomultiplet into a charged cluster and members of the corresponding daughter isomultiplet are equidistant. This relationship is well satisfied for isomultiplets with /ital A/less than or equal to60. By extrapolating the rule for fission and decay energies to the region of heavy nuclei, the excitation energies /ital E//sub /ital x// of double isobar-analog states (DIASs) are found for the nuclei /sup 197,199/Hg, /sup 205/Pb, /sup 205 - -209/Po, /sup 209/At, and /sup 238/Pu. A comparison of the computed energies /ital E//sub /ital x// with the experimentally measured values for /sup 208/Po attest to the reliability and good accuracy of the method proposed here when used to determine the excitation energies of DIASs in heavy nuclei.

  9. Nature of ground and electronic excited states of higher acenes.

    PubMed

    Yang, Yang; Davidson, Ernest R; Yang, Weitao

    2016-08-30

    Higher acenes have drawn much attention as promising organic semiconductors with versatile electronic properties. However, the nature of their ground state and electronic excited states is still not fully clear. Their unusual chemical reactivity and instability are the main obstacles for experimental studies, and the potentially prominent diradical character, which might require a multireference description in such large systems, hinders theoretical investigations. Here, we provide a detailed answer with the particle-particle random-phase approximation calculation. The (1)Ag ground states of acenes up to decacene are on the closed-shell side of the diradical continuum, whereas the ground state of undecacene and dodecacene tilts more to the open-shell side with a growing polyradical character. The ground state of all acenes has covalent nature with respect to both short and long axes. The lowest triplet state (3)B2u is always above the singlet ground state even though the energy gap could be vanishingly small in the polyacene limit. The bright singlet excited state (1)B2u is a zwitterionic state to the short axis. The excited (1)Ag state gradually switches from a double-excitation state to another zwitterionic state to the short axis, but always keeps its covalent nature to the long axis. An energy crossing between the (1)B2u and excited (1)Ag states happens between hexacene and heptacene. Further energetic consideration suggests that higher acenes are likely to undergo singlet fission with a low photovoltaic efficiency; however, the efficiency might be improved if a singlet fission into multiple triplets could be achieved. PMID:27528690

  10. Electron cloud effects in intense, ion beam linacs theory and experimental planning for heavy-ion fusion

    SciTech Connect

    Molvik, A.W.; Cohen, R.H.; Lund, S.M.; Bieniosek, F.M.; Lee, E.P.; Prost, L.R.; Seidl, P.A.; Vay, Jean-Luc

    2002-05-21

    Heavy-ion accelerators for HIF will operate at high aperture-fill factors with high beam current and long pulses. This will lead to beam ions impacting walls: liberating gas molecules and secondary electrons. Without special preparation a large fractional electron population ({approx}>1%) is predicted in the High-Current Experiment (HCX), but wall conditioning and other mitigation techniques should result in substantial reduction. Theory and particle-in-cell simulations suggest that electrons, from ionization of residual and desorbed gas and secondary electrons from vacuum walls, will be radially trapped in the {approx}4 kV ion beam potential. Trapped electrons can modify the beam space charge, vacuum pressure, ion transport dynamics, and halo generation, and can potentially cause ion-electron instabilities. Within quadrupole (and dipole) magnets, the longitudinal electron flow is limited to drift velocities (E x B and {del}B) and the electron density can vary azimuthally, radially, and longitudinally. These variations can cause centroid misalignment, emittance growth and halo growth. Diagnostics are being developed to measure the energy and flux of electrons and gas evolved from walls, and the net charge and gas density within magnetic quadrupoles, as well as the their effect on the ion beam.

  11. Experimental Studies of Interacting Electronic States in NaCs

    NASA Astrophysics Data System (ADS)

    Faust, Carl E.

    This dissertation describes methods and results of spectroscopic studies of the NaCs molecule. NaCs is of particular interest in many labs where experimental studies of ultra-cold molecules are being conducted. Data obtained in the present work will also be useful as benchmarks for various theoretical calculations. Our goals in studying this molecule were to map out high lying electronic states and to understand how these states interact with one another. Sodium and cesium metal were heated in a heat-pipe oven to form a vapor of NaCs molecules. These molecules were excited using narrow band, continuous wave (cw), tunable lasers. We employed the optical-optical double resonance (OODR) technique to obtain Doppler-free spectra of transitions to rotational and vibrational levels of high lying electronic states. One state of particular interest was the 12(0+) electronic state. Rovibrational level energies corresponding to this state were measured and used to generate a potential energy curve using computer programs to implement both the Rydberg-Klein-Rees (RKR) method and the inverted perturbation approach (IPA). By observing fluorescence from the 12(0+) state resolved as a function of wavelength, we determined that this state interacts with the nearby 11(0+) electronic state, which was previously mapped out by Ashman et al. A two-stage coupling model was devised to describe the resolved fluorescence originating from these two interacting states. The electronic states interact via spin-orbit coupling, while the individual rovibrational levels interact via a second mechanism, likely nonadiabatic coupling. This two-stage coupling between the levels of these states causes quantum interference between fluorescence pathways associated with different components of the wavefunctions describing these levels. This interference results in more complicated resolved fluorescence spectra. The model was used to fit parameters describing these interactions so that the resolved

  12. A deterministic electron, photon, proton and heavy ion transport suite for the study of the Jovian moon Europa

    NASA Astrophysics Data System (ADS)

    Badavi, Francis F.; Blattnig, Steve R.; Atwell, William; Nealy, John E.; Norman, Ryan B.

    2011-02-01

    A Langley research center (LaRC) developed deterministic suite of radiation transport codes describing the propagation of electron, photon, proton and heavy ion in condensed media is used to simulate the exposure from the spectral distribution of the aforementioned particles in the Jovian radiation environment. Based on the measurements by the Galileo probe (1995-2003) heavy ion counter (HIC), the choice of trapped heavy ions is limited to carbon, oxygen and sulfur (COS). The deterministic particle transport suite consists of a coupled electron photon algorithm (CEPTRN) and a coupled light heavy ion algorithm (HZETRN). The primary purpose for the development of the transport suite is to provide a means to the spacecraft design community to rapidly perform numerous repetitive calculations essential for electron, photon, proton and heavy ion exposure assessment in a complex space structure. In this paper, the reference radiation environment of the Galilean satellite Europa is used as a representative boundary condition to show the capabilities of the transport suite. While the transport suite can directly access the output electron and proton spectra of the Jovian environment as generated by the jet propulsion laboratory (JPL) Galileo interim radiation electron (GIRE) model of 2003; for the sake of relevance to the upcoming Europa Jupiter system mission (EJSM), the JPL provided Europa mission fluence spectrum, is used to produce the corresponding depth dose curve in silicon behind a default aluminum shield of 100 mils (˜0.7 g/cm2). The transport suite can also accept a geometry describing ray traced thickness file from a computer aided design (CAD) package and calculate the total ionizing dose (TID) at a specific target point within the interior of the vehicle. In that regard, using a low fidelity CAD model of the Galileo probe generated by the authors, the transport suite was verified versus Monte Carlo (MC) simulation for orbits JOI-J35 of the Galileo probe

  13. Correlation between ground state and orbital anisotropy in heavy fermion materials

    SciTech Connect

    Willers, Thomas; Strigari, Fabio; Hu, Zhiwei; Sessi, Violetta; Brookes, Nicholas B.; Bauer, Eric D.; Sarrao, John L.; Thompson, J. D.; Tanaka, Arata; Wirth, Steffen; Tjeng, Liu Hao; Severing, Andrea

    2015-02-09

    The interplay of structural, orbital, charge, and spin degrees of freedom is at the heart of many emergent phenomena, including superconductivity. We find that unraveling the underlying forces of such novel phases is a great challenge because it not only requires understanding each of these degrees of freedom, it also involves accounting for the interplay between them. Cerium-based heavy fermion compounds are an ideal playground for investigating these interdependencies, and we present evidence for a correlation between orbital anisotropy and the ground states in a representative family of materials. We have measured the 4f crystal-electric field ground-state wave functions of the strongly correlated materials CeRh1₋xIrxIn5 with great accuracy using linear polarization-dependent soft X-ray absorption spectroscopy. These measurements show that these wave functions correlate with the ground-state properties of the substitution series, which covers long-range antiferromagnetic order, unconventional superconductivity, and coexistence of these two states.

  14. Correlation between ground state and orbital anisotropy in heavy fermion materials

    DOE PAGESBeta

    Willers, Thomas; Strigari, Fabio; Hu, Zhiwei; Sessi, Violetta; Brookes, Nicholas B.; Bauer, Eric D.; Sarrao, John L.; Thompson, J. D.; Tanaka, Arata; Wirth, Steffen; et al

    2015-02-09

    The interplay of structural, orbital, charge, and spin degrees of freedom is at the heart of many emergent phenomena, including superconductivity. We find that unraveling the underlying forces of such novel phases is a great challenge because it not only requires understanding each of these degrees of freedom, it also involves accounting for the interplay between them. Cerium-based heavy fermion compounds are an ideal playground for investigating these interdependencies, and we present evidence for a correlation between orbital anisotropy and the ground states in a representative family of materials. We have measured the 4f crystal-electric field ground-state wave functions ofmore » the strongly correlated materials CeRh1₋xIrxIn5 with great accuracy using linear polarization-dependent soft X-ray absorption spectroscopy. These measurements show that these wave functions correlate with the ground-state properties of the substitution series, which covers long-range antiferromagnetic order, unconventional superconductivity, and coexistence of these two states.« less

  15. Correlation between ground state and orbital anisotropy in heavy fermion materials

    PubMed Central

    Willers, Thomas; Strigari, Fabio; Hu, Zhiwei; Sessi, Violetta; Brookes, Nicholas B.; Bauer, Eric D.; Sarrao, John L.; Thompson, J. D.; Tanaka, Arata; Wirth, Steffen; Tjeng, Liu Hao; Severing, Andrea

    2015-01-01

    The interplay of structural, orbital, charge, and spin degrees of freedom is at the heart of many emergent phenomena, including superconductivity. Unraveling the underlying forces of such novel phases is a great challenge because it not only requires understanding each of these degrees of freedom, it also involves accounting for the interplay between them. Cerium-based heavy fermion compounds are an ideal playground for investigating these interdependencies, and we present evidence for a correlation between orbital anisotropy and the ground states in a representative family of materials. We have measured the 4f crystal-electric field ground-state wave functions of the strongly correlated materials CeRh1−xIrxIn5 with great accuracy using linear polarization-dependent soft X-ray absorption spectroscopy. These measurements show that these wave functions correlate with the ground-state properties of the substitution series, which covers long-range antiferromagnetic order, unconventional superconductivity, and coexistence of these two states. PMID:25675488

  16. A many-body states picture of electronic friction: The case of multiple orbitals and multiple electronic states.

    PubMed

    Dou, Wenjie; Subotnik, Joseph E

    2016-08-01

    We present a very general form of electronic friction as present when a molecule with multiple orbitals hybridizes with a metal electrode. To develop this picture of friction, we embed the quantum-classical Liouville equation (QCLE) within a classical master equation (CME). Thus, this article extends our previous work analyzing the case of one electronic level, as we may now treat the case of multiple levels and many electronic molecular states. We show that, in the adiabatic limit, where electron transitions are much faster than nuclear motion, the QCLE-CME reduces to a Fokker-Planck equation, such that nuclei feel an average force as well as friction and a random force-as caused by their interaction with the metallic electrons. Finally, we show numerically and analytically that our frictional results agree with other published results calculated using non-equilibrium Green's functions. Numerical recipes for solving this QCLE-CME will be provided in a subsequent paper. PMID:27497534

  17. A many-body states picture of electronic friction: The case of multiple orbitals and multiple electronic states

    NASA Astrophysics Data System (ADS)

    Dou, Wenjie; Subotnik, Joseph E.

    2016-08-01

    We present a very general form of electronic friction as present when a molecule with multiple orbitals hybridizes with a metal electrode. To develop this picture of friction, we embed the quantum-classical Liouville equation (QCLE) within a classical master equation (CME). Thus, this article extends our previous work analyzing the case of one electronic level, as we may now treat the case of multiple levels and many electronic molecular states. We show that, in the adiabatic limit, where electron transitions are much faster than nuclear motion, the QCLE-CME reduces to a Fokker-Planck equation, such that nuclei feel an average force as well as friction and a random force—as caused by their interaction with the metallic electrons. Finally, we show numerically and analytically that our frictional results agree with other published results calculated using non-equilibrium Green's functions. Numerical recipes for solving this QCLE-CME will be provided in a subsequent paper.

  18. Controlling autoionization in strontium two-electron-excited states

    NASA Astrophysics Data System (ADS)

    Fields, Robert; Zhang, Xinyue; Dunning, F. Barry; Yoshida, Shuhei; Burgdörfer, Joachim

    2016-05-01

    One challenge in engineering long-lived two-electron-excited states, i.e., so-called planetary atoms, is autoionization. Autoionization, however, can be suppressed if the outermost electron is placed in a high- n, n ~ 300 - 600 , high- L state because such states have only a very small overlap with the inner electron, even when this is also excited to a state of relatively high n and hence of relatively long lifetime. Here the L-dependence of the autoionization rate for high- n strontium Rydberg atoms is examined during excitation of the core ion 5 s 2S1 / 2 - 5 p 2P3 / 2 transition. Measurements in which the angular momentum of the Rydberg electron is controlled using a pulsed electric field show that the autoionization rate decreases rapidly with increasing L and becomes very small for values larger than ~ 20 . The data are analyzed with the aid of calculations undertaken using complex scaling. Research supported by the NSF and Robert A. Welch Foundation.

  19. Imaging the dynamics of free-electron Landau states

    PubMed Central

    Schattschneider, P.; Schachinger, Th.; Stöger-Pollach, M.; Löffler, S.; Steiger-Thirsfeld, A.; Bliokh, K. Y.; Nori, Franco

    2014-01-01

    Landau levels and states of electrons in a magnetic field are fundamental quantum entities underlying the quantum Hall and related effects in condensed matter physics. However, the real-space properties and observation of Landau wave functions remain elusive. Here we report the real-space observation of Landau states and the internal rotational dynamics of free electrons. States with different quantum numbers are produced using nanometre-sized electron vortex beams, with a radius chosen to match the waist of the Landau states, in a quasi-uniform magnetic field. Scanning the beams along the propagation direction, we reconstruct the rotational dynamics of the Landau wave functions with angular frequency ~100 GHz. We observe that Landau modes with different azimuthal quantum numbers belong to three classes, which are characterized by rotations with zero, Larmor and cyclotron frequencies, respectively. This is in sharp contrast to the uniform cyclotron rotation of classical electrons, and in perfect agreement with recent theoretical predictions. PMID:25105563

  20. OhioLINK Electronic Journal Use at Ohio State University

    ERIC Educational Resources Information Center

    Connell, Tschera Harkness; Rogers, Sally A.; Diedrichs, Carol Pitts

    2005-01-01

    A five-question survey randomly presented to users at Ohio State University (OSU) as they viewed articles in OhioLINK's Electronic Journal Center (EJC) in fall 2002 probed the user's status, academic unit, reason for viewing, path to the article, and frequency of EJC use. Usage by faculty and graduate students, by frequent users, and by those in…

  1. Tuning ground states and excitations in complex electronic materials

    SciTech Connect

    Bishop, A.R.

    1996-09-01

    Modern electronic materials are characterized by a great variety of broken-symmetry ground states and excitations. Their control requires understanding and tuning underlying driving forces of spin-charge-lattice coupling, critical to macroscopic properties and applications. We report representative model calculations which demonstrate some of the richness of the phenomena and the challenges for successful microscopic modeling.

  2. DETERMINING THE ORIGINS OF ELECTRONIC STATES IN SEMICONDUCTOR NANOSTRUCTURES

    SciTech Connect

    Goldman, Rachel

    2014-12-16

    With support from this program, we have generated key results in quantum dot (QD) formation, strain/electronic coupling, measurement and modeling of confined states, and examination of the influence of QDs on thermoelectric and photovoltaic properties of nanocomposite structures. This final report contains a description of our key findings followed by a list of personnel supported and publications generated.

  3. Student Satisfaction with Electronic Library Resources at Wayne State University

    ERIC Educational Resources Information Center

    Holley, Robert P.; Powell, Ronald R.

    2004-01-01

    This paper reports the results of a survey of student satisfaction with electronic library resources other than the online catalog at Wayne State University. Undertaken in Fall Term 2000 as a class project for a marketing course, a student team designed, administered, and analyzed a survey of a random sample of students. Almost 40% of the…

  4. Imaging the dynamics of free-electron Landau states.

    PubMed

    Schattschneider, P; Schachinger, Th; Stöger-Pollach, M; Löffler, S; Steiger-Thirsfeld, A; Bliokh, K Y; Nori, Franco

    2014-01-01

    Landau levels and states of electrons in a magnetic field are fundamental quantum entities underlying the quantum Hall and related effects in condensed matter physics. However, the real-space properties and observation of Landau wave functions remain elusive. Here we report the real-space observation of Landau states and the internal rotational dynamics of free electrons. States with different quantum numbers are produced using nanometre-sized electron vortex beams, with a radius chosen to match the waist of the Landau states, in a quasi-uniform magnetic field. Scanning the beams along the propagation direction, we reconstruct the rotational dynamics of the Landau wave functions with angular frequency ~100 GHz. We observe that Landau modes with different azimuthal quantum numbers belong to three classes, which are characterized by rotations with zero, Larmor and cyclotron frequencies, respectively. This is in sharp contrast to the uniform cyclotron rotation of classical electrons, and in perfect agreement with recent theoretical predictions. PMID:25105563

  5. International Symposium on Ion Therapy: Planning the First Hospital-Based Heavy Ion Therapy Center in the United States

    PubMed Central

    Laine, Aaron; Pompos, Arnold; Story, Michael; Jiang, Steve; Timmerman, Robert; Choy, Hak

    2015-01-01

    Investigation into the use of heavy ions for therapeutic purposes was initially pioneered at Lawrence Berkeley National Laboratory in the 1970s [1, 2]. More recently, however, significant advances in determining the safety and efficacy of using heavy ions in the hospital setting have been reported in Japan and Germany [3, 4]. These promising results have helped to resurrect interest in the establishment of hospital-based heavy ion therapy in the United States. In line with these efforts, world experts in the field of heavy ion therapy were invited to attend the first annual International Symposium on Ion Therapy, which was held at the University of Texas Southwestern Medical Center, Dallas, Texas, from November 12 to 14, 2014. A brief overview of the results and discussions that took place during the symposium are presented in this article. PMID:27110586

  6. Electron-state tuning of multilayer graphene by defects

    NASA Astrophysics Data System (ADS)

    Kishimoto, Ken; Okada, Susumu

    2016-06-01

    Electronic band structures of graphene thin films, in which the topmost layer possesses atomic and topological defects, are studied using the density functional theory. Our calculations showed that all graphene thin films studied here have a finite energy gap in their π electron states, although the thin films possess defect-free hexagonal networks, because of the spatially undulated local potential on pristine graphene layers induced by the defects. The energy gap in π states slightly decreases with increasing number of layers, while the gap sensitively depends on the interlayer stacking arrangement. Our analyses clarify that the interlayer interaction plays a crucial role for mediating the effect of the defects on the π electrons of pristine layers.

  7. Comparison of Hydrodynamic Calculations of Heavy Ion Collisions with Different Equations of State

    NASA Astrophysics Data System (ADS)

    Soltz, Ron; Moreland, Scott

    2015-10-01

    The QCD Equation of State (EoS) is an essential ingredient for the hydrodynamic models used to study heavy ion collisions. Recent results by the HotQCD and Wuppertal-Budapest collaborations lattice gauge calculations of the QCD EoS at the continuum limit show good agreement within errors. However it is unknown whether current errors are sufficient for current simulations or whether further improvements are needed. We explore this question by performing hydrodynamic calculations with the VISHNU 2+1D hydrodynamic code with fluctuating initial conditions and UrQMD cascade code for the two EoS calculations and a sampling of EoS curves within the given errors. Comparisons are made to spectra (π, K, p), flow (v2 ,v3), and azimuthally averaged HBT radii for 200 GeV Au+Au collisions. Relative variations in the results and comparisons to data where appropriate will be presented and discussed.

  8. Measurement of electrons from heavy-flavour hadron decays in p-Pb collisions at √{sNN} = 5.02TeV

    NASA Astrophysics Data System (ADS)

    Adam, J.; Adamová, D.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahn, S. U.; Aiola, S.; Akindinov, A.; Alam, S. N.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alfaro Molina, R.; Alici, A.; Alkin, A.; Almaraz, J. R. M.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Alves Garcia Prado, C.; Andrei, C.; Andronic, A.; Anguelov, V.; Anielski, J.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Arnaldi, R.; Arnold, O. W.; Arsene, I. C.; Arslandok, M.; Audurier, B.; Augustinus, A.; Averbeck, R.; Azmi, M. D.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldisseri, A.; Baral, R. C.; Barbano, A. M.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartalini, P.; Barth, K.; Bartke, J.; Bartsch, E.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bello Martinez, H.; Bellwied, R.; Belmont, R.; Belmont-Moreno, E.; Belyaev, V.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Biswas, R.; Biswas, S.; Bjelogrlic, S.; Blair, J. T.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bøggild, H.; Boldizsár, L.; Bombara, M.; Book, J.; Borel, H.; Borissov, A.; Borri, M.; Bossú, F.; Botta, E.; Böttger, S.; Bourjau, C.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Brucken, E. J.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Butt, J. B.; Buxton, J. T.; Caffarri, D.; Cai, X.; Caines, H.; Calero Diaz, L.; Caliva, A.; Calvo Villar, E.; Camerini, P.; Carena, F.; Carena, W.; Carnesecchi, F.; Castillo Castellanos, J.; Castro, A. J.; Casula, E. A. R.; Ceballos Sanchez, C.; Cepila, J.; Cerello, P.; Cerkala, J.; Chang, B.; Chapeland, S.; Chartier, M.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Cho, S.; Chochula, P.; Choi, K.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Conesa Balbastre, G.; Conesa del Valle, Z.; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortés Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Crochet, P.; Cruz Albino, R.; Cuautle, E.; Cunqueiro, L.; Dahms, T.; Dainese, A.; Danu, A.; Das, D.; Das, I.; Das, S.; Dash, A.; Dash, S.; De, S.; De Caro, A.; de Cataldo, G.; de Conti, C.; de Cuveland, J.; De Falco, A.; De Gruttola, D.; De Marco, N.; De Pasquale, S.; Deisting, A.; Deloff, A.; Dénes, E.; Deplano, C.; Dhankher, P.; Di Bari, D.; Di Mauro, A.; Di Nezza, P.; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; Djuvsland, Ø.; Dobrin, A.; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Drozhzhova, T.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Ehlers, R. J.; Elia, D.; Engel, H.; Epple, E.; Erazmus, B.; Erdemir, I.; Erhardt, F.; Espagnon, B.; Estienne, M.; Esumi, S.; Eum, J.; Evans, D.; Evdokimov, S.; Eyyubova, G.; Fabbietti, L.; Fabris, D.; Faivre, J.; Fantoni, A.; Fasel, M.; Feldkamp, L.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Feuillard, V. J. G.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Fleck, M. G.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Frankenfeld, U.; Fuchs, U.; Furget, C.; Furs, A.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gallio, M.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-Solis, E.; Gargiulo, C.; Gasik, P.; Gauger, E. F.; Germain, M.; Gheata, A.; Gheata, M.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Giubilato, P.; Gladysz-Dziadus, E.; Glässel, P.; Goméz Coral, D. M.; Gomez Ramirez, A.; Gonzalez, V.; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Grabski, V.; Grachov, O. A.; Graczykowski, L. K.; Graham, K. L.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Gronefeld, J. M.; Grosse-Oetringhaus, J. F.; Grossiord, J.-Y.; Grosso, R.; Guber, F.; Guernane, R.; Guerzoni, B.; Gulbrandsen, K.; Gunji, T.; Gupta, A.; Gupta, R.; Haake, R.; Haaland, Ø.; Hadjidakis, C.

    2016-03-01

    The production of electrons from heavy-flavour hadron decays was measured as a function of transverse momentum (pT) in minimum-bias p-Pb collisions at √{sNN} = 5.02 TeV using the ALICE detector at the LHC. The measurement covers the pT interval 0.5 electrons from background sources was subtracted using an invariant mass approach. The nuclear modification factor RpPb was calculated by comparing the pT-differential invariant cross section in p-Pb collisions to a pp reference at the same centre-of-mass energy, which was obtained by interpolating measurements at √{ s} = 2.76 TeV and √{ s} = 7 TeV. The RpPb is consistent with unity within uncertainties of about 25%, which become larger for pT below 1 GeV / c. The measurement shows that heavy-flavour production is consistent with binary scaling, so that a suppression in the high-pT yield in Pb-Pb collisions has to be attributed to effects induced by the hot medium produced in the final state. The data in p-Pb collisions are described by recent model calculations that include cold nuclear matter effects.

  9. Charge and electronic states of cuprite: Experiment and theory

    NASA Astrophysics Data System (ADS)

    Kim, Miyoung

    The bonding characteristics of cuprite have been studied by the using convergent beam electron diffraction (CBED) method. The low-order structure factors are closely related to the valence electron density, and the CBED is one of the most accurate methods of measuring the low order structure factors. The multipole model is used for converting the structure factors into charge density. The multipole expansion takes into account non-spherical valence electron density due to atomic bonding based on the crystal symmetry. The charge transfer from copper to oxygen is determined from the multipole fitting parameters. The hybridization state between 4s-3d orbitals of copper is also estimated. Electronic states of CU2O are investigated by studying the fine structure of the electron-energy loss spectrum (EELS). The cross section of the near edge structure is proportional to the density of state times an atomic transition site-projected matrix element which generally varies slowly in the region of interest. Both the fine structure of Cu- L2'3 and O-K of Cu2O are significantly different from those of CuO, which shows the sensitivity of EELS fine structure to the crystal bonding. Full-potential Linearized Augmented Plane Wave (FLAPW) calculations have been used to compare experimental results with theory. The structure factors and bonding charge density are compared with the results obtained by the CBED method, and the density of states is compared with the EELS. The FLAPW method has also been used in the local density approximations CLDA) to calculate values of the mean inner Coulomb potential V 0 for Si, Ge and MgO. These values are compared with recent measurements by electron holography. The supercell calculations are performed for crystal slabs, so that the effects of different crystal orientations and surface structures on V0 can be evaluated.

  10. Foucault's Pendulum, Analog for an Electron Spin State

    NASA Astrophysics Data System (ADS)

    Linck, Rebecca

    2012-11-01

    The classical Lagrangian that describes the coupled oscillations of Foucault's pendulum presents an interesting analog to an electron's spin state in an external magnetic field. With a simple modification, this classical Lagrangian yields equations of motion that directly map onto the Schrodinger-Pauli Equation. This analog goes well beyond the geometric phase, reproducing a broad range of behavior from Zeeman-like frequency splitting to precession of the spin state. By demonstrating that unmeasured spin states can be fully described in classical terms, this research opens the door to using the tools of classical physics to examine an inherently quantum phenomenon.

  11. Two Electron States in a Quantum Ring on a Sphere

    NASA Astrophysics Data System (ADS)

    Kazaryan, Eduard M.; Shahnazaryan, Vanik A.; Sarkisyan, Hayk A.

    2014-02-01

    Two electron states in a quantum ring on a spherical surface are discussed. The problem is discussed within the frameworks of Russell-Saunders coupling scheme, that is, the spin-orbit coupling is neglected. Treating Coulomb interaction as a perturbation, the energy correction for different states is calculated. The dependence of the Coulomb interaction energy on external polar boundary angle of quantum ring is obtained. In analogue with the helium atom the concept of states exchange time is introduced, and its dependence on geometrical parameters of the ring is shown.

  12. The Electronic Properties of Superatom States of Hollow Molecules

    SciTech Connect

    Feng, Min; Zhao, Jin; Huang, Tian; Zhu, Xiaoyang; Petek, Hrvoje

    2011-05-17

    Electronic and optical properties of molecules and molecular solids are traditionally considered from the perspective of the frontier orbitals and their intermolecular interactions. How molecules condense into crystalline solids, however, is mainly attributed to the long-range polarization interaction. In this Account, we show that long-range polarization also introduces a distinctive set of diffuse molecular electronic states, which in quantum structures or solids can combine into nearly-free-electron (NFE) bands. These NFE properties, which are usually associated with good metals, are vividly evident in sp2 hybridized carbon materials, specifically graphene and its derivatives. The polarization interaction is primarily manifested in the screening of an external charge at a solid/vacuum interface. It is responsible for the universal image potential and the associated unoccupied image potential (IP) states, which are observed even at the He liquid/vacuum interface. The molecular electronic properties that we describe are derived from the IP states of graphene, which float above and below the molecular plane and undergo free motion parallel to it. Rolling or wrapping a graphene sheet into a nanotube or a fullerene transforms the IP states into diffuse atom-like orbitals that are bound primarily to hollow molecular cores, rather than the component atoms. Therefore, we named them the superatom molecular orbitals (SAMOs). Like the excitonic states of semiconductor nanostructures or the plasmonic resonances of metallic nanoparticles, SAMOs of fullerene molecules, separated by their van der Waals distance, can combine to form diatomic molecule-like orbitals of C60 dimers. For larger aggregates, they form NFE bands of superatomic quantum structures and solids. The overlap of the diffuse SAMO wavefunctions in van der Waals solids provides a different paradigm for band formation than the valence or conduction bands formed by interaction of the more tightly bound

  13. A Deterministic Electron, Photon, Proton and Heavy Ion Radiation Transport Suite for the Study of the Jovian System

    NASA Technical Reports Server (NTRS)

    Norman, Ryan B.; Badavi, Francis F.; Blattnig, Steve R.; Atwell, William

    2011-01-01

    A deterministic suite of radiation transport codes, developed at NASA Langley Research Center (LaRC), which describe the transport of electrons, photons, protons, and heavy ions in condensed media is used to simulate exposures from spectral distributions typical of electrons, protons and carbon-oxygen-sulfur (C-O-S) trapped heavy ions in the Jovian radiation environment. The particle transport suite consists of a coupled electron and photon deterministic transport algorithm (CEPTRN) and a coupled light particle and heavy ion deterministic transport algorithm (HZETRN). The primary purpose for the development of the transport suite is to provide a means for the spacecraft design community to rapidly perform numerous repetitive calculations essential for electron, proton and heavy ion radiation exposure assessments in complex space structures. In this paper, the radiation environment of the Galilean satellite Europa is used as a representative boundary condition to show the capabilities of the transport suite. While the transport suite can directly access the output electron spectra of the Jovian environment as generated by the Jet Propulsion Laboratory (JPL) Galileo Interim Radiation Electron (GIRE) model of 2003; for the sake of relevance to the upcoming Europa Jupiter System Mission (EJSM), the 105 days at Europa mission fluence energy spectra provided by JPL is used to produce the corresponding dose-depth curve in silicon behind an aluminum shield of 100 mils ( 0.7 g/sq cm). The transport suite can also accept ray-traced thickness files from a computer-aided design (CAD) package and calculate the total ionizing dose (TID) at a specific target point. In that regard, using a low-fidelity CAD model of the Galileo probe, the transport suite was verified by comparing with Monte Carlo (MC) simulations for orbits JOI--J35 of the Galileo extended mission (1996-2001). For the upcoming EJSM mission with a potential launch date of 2020, the transport suite is used to compute

  14. Medium-energy electrons and heavy ions in Jupiter's magnetosphere - Effects of lower hybrid wave-particle interactions

    NASA Technical Reports Server (NTRS)

    Barbosa, D. D.

    1986-01-01

    A theory of medium-energy (about keV) electrons and heavy ions in Jupiter's magnetosphere is presented. Lower hybrid waves are generated by the combined effects of a ring instability of neutral wind pickup ions and the modified two-stream instability associated with transport of cool Iogenic plasma. The quasi-linear energy diffusion coefficient for lower hybrid wave-particle interactions is evaluated, and several solutions to the diffusion equation are given. Calculations based on measured wave properties show that the noise substantially modifies the particle distribution functions. The effects are to accelerate superthermal ions and electrons to keV energies and to thermalize the pickup ions on time scales comparable to the particle residence time. The S(2+)/S(+) ratio at medium energies is a measure of the relative contribution from Iogenic thermal plasma and neutral wind ions, and this important quantity should be determined from future measurements. The theory also predicts a preferential acceleration of heavy ions with an accleration time that scales inversely with the root of the ion mass. Electrons accelerated by the process contribute to further reionization of the neutral wind by electron impact, thus providing a possible confirmation of Alfven's critical velocity effect in the Jovian magnetosphere.

  15. Calculation of electron scattering from the ground state of ytterbium

    SciTech Connect

    Bostock, Christopher J.; Fursa, Dmitry V.; Bray, Igor

    2011-05-15

    We report on the application of the convergent close-coupling method, in both relativistic and nonrelativistic formulations, to electron scattering from ytterbium. Angle-differential and integrated cross sections are presented for elastic scattering and excitation of the states (6s6p){sup 3}P{sub 0,1,2}, (6s6p){sup 1}P{sub 1}{sup o}, (6s7p){sup 1}P{sub 1}{sup o}, and (6s5d){sup 1}D{sub 2}{sup e} for a range of incident electron energies. We also present calculations of the total cross section, and angle-differential Stokes parameters for excitation of the (6s6p){sup 3}P{sub 1}{sup o} state from the ground state. A comparison is made with the relativistic distorted-wave method and experiments.

  16. Foucault's pendulum, a classical analog for the electron spin state

    NASA Astrophysics Data System (ADS)

    Linck, Rebecca A.

    Spin has long been regarded as a fundamentally quantum phenomena that is incapable of being described classically. To bridge the gap and show that aspects of spin's quantum nature can be described classically, this work uses a classical Lagrangian based on the coupled oscillations of Foucault's pendulum as an analog for the electron spin state in an external magnetic field. With this analog it is possible to demonstrate that Foucault's pendulum not only serves as a basis for explaining geometric phase, but is also a basis for reproducing a broad range of behavior from Zeeman-like frequency splitting to precession of the spin state. By demonstrating that unmeasured electron spin states can be fully described in classical terms, this research opens the door to using the tools of classical physics to examine an inherently quantum phenomenon.

  17. Interaction of thyroid state and denervation on skeletal myosin heavy chain expression

    NASA Technical Reports Server (NTRS)

    Haddad, F.; Arnold, C.; Zeng, M.; Baldwin, K.

    1997-01-01

    The goal of this study was to examine the effects of altered thyroid state and denervation (Den) on skeletal myosin heavy chain (MHC) expression in the plantaris and soleus muscles. Rats were subjected to unilateral denervation (Den) and randomly assigned to one of three groups: (1) euthyroid; (2) hyperthyroid; (3) and hypothyroid. Denervation caused severe muscle atrophy and muscle-type specific MHC transformation. Denervation transformed the soleus to a faster muscle, and its effects required the presence of circulating thyroid hormone. In contrast, denervation transformed the plantaris to a slower muscle independently of thyroid state. Furthermore, thyroid hormone effects did not depend upon innervation status in the soleus, while they required the presence of the nerve in the plantaris. Collectively, these findings suggest that both thyroid hormone and intact nerve (a) differentially affect MHC transformations in fast and slow muscle; and (b) are important factors in regulating the optimal expression of both type I and IIB MHC genes. This research suggests that for patients with nerve damage and/or paralysis, both muscle mass and biochemical properties can also be affected by the thyroid state.

  18. Development of High Resolution Solid-State Track Detector for Ultra Heavy Cosmic Ray Observation

    NASA Astrophysics Data System (ADS)

    Kodaira, S.; Doke, T.; Hareyama, M.; Hasebe, N.; Ota, S.; Sakurai, K.; Sato, M.; Yasuda, N.; Nakamura, S.; Kamei, T.; Tawara, H.; Ogura, K.

    The observation of trans-iron nuclei in galactic cosmic rays (Z?30) requires a high performance cosmic ray detector telescope with a very large exposure area because of their extremely low fluxes. It is realized by the use of solid-state track detector of CR-39, which has an advantage of easy extension of exposure area. The verification of mass and nuclear charge identifications with CR-39 solid-state track detector newly developed for the observation of heavy cosmic ray particles has been made using Fe ions from NIRS-HIMAC. Mass and charge resolutions for Fe nuclei are found to be ~0.22 amu and 0.22 cu in rms, respectively. Moreover, it is necessary to raise the Z/??detection threshold in order to suppress background tracks produced by galactic cosmic rays with Z/?<30. The new track detectors of copolymers of CR-39 and DAP (diallyl phthalate) have been developed and verified their performances. From the point of view of stability for the cosmic ray exposure environment such as temperature and vacuum in space, newly BP-1 glass detector with high sensitivity is also currently under development. The combination of such solid-state track detector with the high speed scanning system enables us to realize a large-scaled observation for trans-iron galactic cosmic rays.

  19. XAFS and XEOL of tetramesityldigermene - An electronic structure study of a heavy group 14 ethylene analogue

    SciTech Connect

    Ward, Matthew J.; Rupar, Paul A.; Murphy, Michael W.; Yiu, Yun-Mui; Baines, Kim M.; Sham, Tsun-Kong

    2013-05-29

    Digermene, the germanium analogue of ethylene, has a multiple bonding motif that differs greatly from that of alkenes and exhibits no pure σ or π type bonds. The electronic structure of digermenes is difficult to study experimentally due to their reactivity, and is computationally challenging because of their shallow potential energy surfaces. Using X-ray absorption near edge structures at both the germanium K and L edges we have been able to directly probe the unoccupied electronic states, or the lowest unoccupied molecular orbital (LUMO), and LUMO+ etc. in the Ge=Ge bond of tetramesityldigermene. We have demonstrated that the LUMO, LUMO+, etc. are composed of hybrid Ge 4s and 4p orbitals. Additionally, our data suggest that the LUMO exhibits relatively more Ge 4s character, whereas the LUMO+ and LUMO+2 exhibit relatively more Ge 4p character. An X-ray excited optical luminescence study of Ge2Mes4 revealed one broad optical emission band at 620 nm, which is significantly red shifted compared to the known energy gap of this molecular germanium compound.

  20. Electronic Structure Calculations for Heavy Elements: Radon (Z=86) and Francium (Z=87)

    NASA Astrophysics Data System (ADS)

    Koufos, Alexander; Papaconstantopoulos, Dimitrios

    2010-03-01

    Electronic structure calculations allow scientists to predict the properties of solids without the use of physical material. Although the ability to manipulate matter has improved dramatically within the past couple decades, some matter is still hard to study. Modern computers not only let us study this matter, but allow us to do it more quickly and just as accurately. The electronic structure of two rare and mostly unstudied elements, Radon (Z=86) and Francium (Z=87), has been calculated. The augmented plane wave (APW) method with local density approximation (LDA) functional as well as the linearized augmented plane wave (LAPW) method with both LDA and generalized gradient approximation (GGA) functionals were used to perform the calculations. Francium total energy calculations gave the fcc structure slightly below the bcc structure with a minimal energy difference of δE=0.33mRy. The difference found is consistent with other alkali metal total energy calculations which do not verify the bcc structure to be the ground state. Radon was predicted to be an insulator with a gap of 0.931 Ry similar to the other noble gases.

  1. Spectroscopic Constants of the Known Electronic States of Lead Monofluoride

    SciTech Connect

    McRaven, C.P.; Sivakumar, P.; Shafer-Ray, N.E.; Hall, G.E.; Sears, T.J.

    2010-08-01

    Based on measurements made by mass-resolved 1 + 1{prime} + 1{double_prime} resonance-enhanced multiphoton ionization spectroscopy, we have determined new molecular constants describing the rotational and fine structure levels of the B, D, E, and F states of the most abundant isotopic variant {sup 208}Pb{sup 19}F, and we summarize the spectroscopic constants for all the know electronic states of the radical. Many spectroscopic constants for the isotopologues {sup 206}Pb{sup 19}F and {sup 207}Pb{sup 19}F have also been determined. The symmetry of the D-state is found to be {sup 2}{pi}{sub 1/2}, and the F-state is found to be an {Omega} = 3/2 state.

  2. Dynamics of neutralizing electrons during the focusing of intenseheavy ions beams inside a heavy fusion reactor chamber

    SciTech Connect

    Lifschitz, Agustin F.; Maynard, Gilles; Vay, Jean-Luc; Lenglet,Andrian

    2006-07-01

    The efficiency of a Heavy Ion Fusion reactor heavily depends on the maximum value for the density of energy (DoE) that can be deposited by the ion beams. In order to reduce the final beam radius, and thus to increase the DoE inside the target, the beam spatial charge has to be neutralized. Therefore the dynamics of the neutralizing electrons (DNE) play a central role in optimizing the DoE deposited in solid targets by the high current of the high energy heavy ion beams. We present results on some aspects of the DNE, which was performed using the Monte-Carlo 2D1/2 PIC code BPIC.

  3. Heavy-flavor electron-muon correlations in p +p and d +Au collisions at √sNN =200 GeV

    NASA Astrophysics Data System (ADS)

    Adare, A.; Afanasiev, S.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Al-Bataineh, H.; Alexander, J.; Angerami, A.; Aoki, K.; Apadula, N.; Aphecetche, L.; Aramaki, Y.; Asai, J.; Atomssa, E. T.; Averbeck, R.; Awes, T. C.; Azmoun, B.; Babintsev, V.; Bai, M.; Baksay, G.; Baksay, L.; Baldisseri, A.; Barish, K. N.; Barnes, P. D.; Bassalleck, B.; Basye, A. T.; Bathe, S.; Batsouli, S.; Baublis, V.; Baumann, C.; Bazilevsky, A.; Belikov, S.; Belmont, R.; Bennett, R.; Berdnikov, A.; Berdnikov, Y.; Bhom, J. H.; Bickley, A. A.; Blau, D. S.; Boissevain, J. G.; Bok, J. S.; Borel, H.; Boyle, K.; Brooks, M. L.; Buesching, H.; Bumazhnov, V.; Bunce, G.; Butsyk, S.; Camacho, C. M.; Campbell, S.; Caringi, A.; Chang, B. S.; Chang, W. C.; Charvet, J.-L.; Chen, C.-H.; Chernichenko, S.; Chi, C. Y.; Chiu, M.; Choi, I. J.; Choi, J. B.; Choudhury, R. K.; Christiansen, P.; Chujo, T.; Chung, P.; Churyn, A.; Chvala, O.; Cianciolo, V.; Citron, Z.; Cole, B. A.; Conesa Del Valle, Z.; Connors, M.; Constantin, P.; Csanád, M.; Csörgő, T.; Dahms, T.; Dairaku, S.; Danchev, I.; Das, K.; Datta, A.; David, G.; Dayananda, M. K.; Denisov, A.; D'Enterria, D.; Deshpande, A.; Desmond, E. J.; Dharmawardane, K. V.; Dietzsch, O.; Dion, A.; Donadelli, M.; Drapier, O.; Drees, A.; Drees, K. A.; Dubey, A. K.; Durham, J. M.; Durum, A.; Dutta, D.; Dzhordzhadze, V.; D'Orazio, L.; Edwards, S.; Efremenko, Y. V.; Ellinghaus, F.; Engelmore, T.; Enokizono, A.; En'yo, H.; Esumi, S.; Eyser, K. O.; Fadem, B.; Fields, D. E.; Finger, M.; Finger, M.; Fleuret, F.; Fokin, S. L.; Fraenkel, Z.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fujiwara, K.; Fukao, Y.; Fusayasu, T.; Garishvili, I.; Glenn, A.; Gong, H.; Gonin, M.; Gosset, J.; Goto, Y.; de Cassagnac, R. Granier; Grau, N.; Greene, S. V.; Grim, G.; Perdekamp, M. Grosse; Gunji, T.; Gustafsson, H.-Å.; Henni, A. Hadj; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Hamblen, J.; Han, R.; Hanks, J.; Hartouni, E. P.; Haruna, K.; Haslum, E.; Hayano, R.; He, X.; Heffner, M.; Hemmick, T. K.; Hester, T.; Hill, J. C.; Hohlmann, M.; Holzmann, W.; Homma, K.; Hong, B.; Horaguchi, T.; Hornback, D.; Huang, S.; Ichihara, T.; Ichimiya, R.; Iinuma, H.; Ikeda, Y.; Imai, K.; Imrek, J.; Inaba, M.; Isenhower, D.; Ishihara, M.; Isobe, T.; Issah, M.; Isupov, A.; Ivanischev, D.; Iwanaga, Y.; Jacak, B. V.; Jia, J.; Jiang, X.; Jin, J.; Johnson, B. M.; Jones, T.; Joo, K. S.; Jouan, D.; Jumper, D. S.; Kajihara, F.; Kametani, S.; Kamihara, N.; Kamin, J.; Kang, J. H.; Kapustinsky, J.; Karatsu, K.; Kasai, M.; Kawall, D.; Kawashima, M.; Kazantsev, A. V.; Kempel, T.; Khanzadeev, A.; Kijima, K. M.; Kikuchi, J.; Kim, A.; Kim, B. I.; Kim, D. H.; Kim, D. J.; Kim, E.; Kim, E.-J.; Kim, S. H.; Kim, Y.-J.; Kinney, E.; Kiriluk, K.; Kiss, Á.; Kistenev, E.; Klay, J.; Klein-Boesing, C.; Kleinjan, D.; Kochenda, L.; Komkov, B.; Konno, M.; Koster, J.; Kozlov, A.; Král, A.; Kravitz, A.; Kunde, G. J.; Kurita, K.; Kurosawa, M.; Kweon, M. J.; Kwon, Y.; Kyle, G. S.; Lacey, R.; Lai, Y. S.; Lajoie, J. G.; Layton, D.; Lebedev, A.; Lee, D. M.; Lee, J.; Lee, K. B.; Lee, K. S.; Lee, T.; Leitch, M. J.; Leite, M. A. L.; Lenzi, B.; Li, X.; Lichtenwalner, P.; Liebing, P.; Levy, L. A. Linden; Liška, T.; Litvinenko, A.; Liu, H.; Liu, M. X.; Love, B.; Lynch, D.; Maguire, C. F.; Makdisi, Y. I.; Malakhov, A.; Malik, M. D.; Manko, V. I.; Mannel, E.; Mao, Y.; Mašek, L.; Masui, H.; Matathias, F.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; Means, N.; Meredith, B.; Miake, Y.; Mibe, T.; Mignerey, A. C.; Mikeš, P.; Miki, K.; Milov, A.; Mishra, M.; Mitchell, J. T.; Mohanty, A. K.; Moon, H. J.; Morino, Y.; Morreale, A.; Morrison, D. P.; Moukhanova, T. V.; Mukhopadhyay, D.; Murakami, T.; Murata, J.; Nagamiya, S.; Nagle, J. L.; Naglis, M.; Nagy, M. I.; Nakagawa, I.; Nakamiya, Y.; Nakamura, K. R.; Nakamura, T.; Nakano, K.; Nam, S.; Newby, J.; Nguyen, M.; Nihashi, M.; Niida, T.; Nouicer, R.; Nyanin, A. S.; Oakley, C.; O'Brien, E.; Oda, S. X.; Ogilvie, C. A.; Oka, M.; Okada, K.; Onuki, Y.; Oskarsson, A.; Ouchida, M.; Ozawa, K.; Pak, R.; Palounek, A. P. T.; Pantuev, V.; Papavassiliou, V.; Park, I. H.; Park, J.; Park, S. K.; Park, W. J.; Pate, S. F.; Pei, H.; Peng, J.-C.; Pereira, H.; Peresedov, V.; Peressounko, D. Yu.; Petti, R.; Pinkenburg, C.; Pisani, R. P.; Proissl, M.; Purschke, M. L.; Purwar, A. K.; Qu, H.; Rak, J.; Rakotozafindrabe, A.; Ravinovich, I.; Read, K. F.; Rembeczki, S.; Reygers, K.; Riabov, V.; Riabov, Y.; Richardson, E.; Roach, D.; Roche, G.; Rolnick, S. D.; Rosati, M.; Rosen, C. A.; Rosendahl, S. S. E.; Rosnet, P.; Rukoyatkin, P.; Ružička, P.; Rykov, V. L.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sakai, S.; Sakashita, K.; Samsonov, V.; Sano, S.; Sato, T.; Sawada, S.; Sedgwick, K.; Seele, J.; Seidl, R.; Semenov, A. Yu.; Semenov, V.; Seto, R.; Sharma, D.; Shein, I.; Shibata, T.-A.; Shigaki, K.; Shimomura, M.; Shoji, K.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Silvestre, C.; Sim, K. S.; Singh, B. K.; Singh, C. P.; Singh, V.; Slunečka, M.; Soldatov, A.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Staley, F.; Stankus, P. W.; Stenlund, E.; Stepanov, M.; Ster, A.; Stoll, S. P.; Sugitate, T.; Suire, C.; Sukhanov, A.; Sziklai, J.; Takagui, E. M.; Taketani, A.; Tanabe, R.; Tanaka, Y.; Taneja, S.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Taranenko, A.; Tarján, P.; Themann, H.; Thomas, D.; Thomas, T. L.; Togawa, M.; Toia, A.; Tomášek, L.; Tomita, Y.; Torii, H.; Towell, R. S.; Tram, V.-N.; Tserruya, I.; Tsuchimoto, Y.; Vale, C.; Valle, H.; van Hecke, H. W.; Vazquez-Zambrano, E.; Veicht, A.; Velkovska, J.; Vértesi, R.; Vinogradov, A. A.; Virius, M.; Vrba, V.; Vznuzdaev, E.; Wang, X. R.; Watanabe, D.; Watanabe, K.; Watanabe, Y.; Wei, F.; Wei, R.; Wessels, J.; White, S. N.; Winter, D.; Woody, C. L.; Wright, R. M.; Wysocki, M.; Xie, W.; Yamaguchi, Y. L.; Yamaura, K.; Yang, R.; Yanovich, A.; Ying, J.; Yokkaichi, S.; You, Z.; Young, G. R.; Younus, I.; Yushmanov, I. E.; Zajc, W. A.; Zaudtke, O.; Zhang, C.; Zhou, S.; Zolin, L.; Phenix Collaboration

    2014-03-01

    Background: Heavy-flavor modification in relativistic p (d)+A collisions are sensitive to different kinds of strong-interaction physics ranging from modifications of the nuclear wave function to initial- and final-state energy loss. Modifications to single heavy-flavor particles and their decay leptons at midrapidity and forward rapidity are well established at the Relativistic Heavy Ion Collider (RHIC). Purpose: This paper presents measurements of azimuthal correlations of electron-muon pairs produced from heavy-flavor decays, primarily cc ¯, in √sNN =200 GeV p +p and d +Au collision using the PHENIX detector at RHIC. The electrons are measured at midrapidity while the muons in the pair are measured at forward rapidity, defined as the direction of the deuteron beam, in order to utilize the deuteron to probe low-x partons in the gold nucleus. Methods: This analysis uses the central spectrometer arms for electron identification and forward spectrometer arms for muon identification. Azimuthal correlations are built in all sign combinations for e-μ pairs. Subtracting the like-sign yield from the unlike-sign yield removes the correlations from light flavor decays and conversions. Results: Comparing the p +p results with several different Monte Carlo event generators, we find the results are consistent with a total charm cross section σcc ¯=538±46 (stat) ± 197 (data syst) ± 174 (model syst) μb. These generators also indicate that the back-to-back peak at Δϕ =π is dominantly from the leading-order contributions (gluon fusion), while higher-order processes (flavor excitation and gluon splitting) contribute to the yield at all Δϕ. We observe a suppression in the pair yield per collision in d +Au. We find the pair yield suppression factor for 2.7<Δϕ<3.2 rad is JdA=0.433±0.087 (stat) ± 0.135 (syst). Conclusions: The e-μ pairs result from partons at xAu˜10-2 at Q2=10 GeV/c2 at the edge of the shadowing region. The pair suppression indicates modification

  4. Complex electronic states in double-layered ruthenates (Sr1-xCax)3Ru2O7

    NASA Astrophysics Data System (ADS)

    Qu, Zhe; Peng, Jin; Liu, Tijiang; Fobes, David; Spinu, Leonard; Mao, Zhiqiang

    2009-09-01

    The magnetic ground state of (Sr1-xCax)3Ru2O7 (0≤x≤1) is complex, ranging from an itinerant metamagnetic state (0≤x<0.08) to an unusual heavy-mass nearly ferromagnetic (FM) state (0.08state (0.4≤x≤1) . In this report we elucidate the electronic properties for these magnetic states, and show that the electronic and magnetic properties are strongly coupled in this system. The electronic ground state evolves from an AFM quasi-two-dimensional metal for x=1.0 to an Anderson localized state for 0.4≤x<1.0 (the AFM region). When the magnetic state undergoes a transition from the AFM to the nearly FM state, the electronic ground state switches to a weakly localized state induced by magnetic scattering for 0.25≤x<0.4 , and then to a magnetic metallic state with the in-plane resistivity ρab∝Tα (α>2) for 0.08state when the magnetic ground state enters the itinerant metamagnetic state for x<0.08 . When x approaches the critical composition (x˜0.08) , the Fermi-liquid temperature is suppressed to zero Kelvin, and non-Fermi-liquid behavior is observed. These results demonstrate the strong interplay between the charge and spin degrees of freedom in the double-layered ruthenates.

  5. Surface States and Negative Electron Affinity in Polyethylene

    SciTech Connect

    Righi, M. C.; Scandolo, S.; Serra, S.; Iarlori, S.; Tosatti, E.; Santoro, G.

    2001-08-13

    First-principles calculations are used to investigate the electronic properties of the surfaces of polyethylene. The calculations support the experimental evidence of a negative electron affinity, with calculated values of -0.17 eV and -0.10 eV for surfaces with chains perpendicular and parallel to the surface normal, respectively. Both surfaces exhibit a surface state with binding energy -1.2{+-}0.5 eV with respect to the bulk polyethylene conduction band minimum. Implications of these findings on spectroscopy, as well as on the transport and aging properties of polyethylene for high-voltage applications, are discussed.

  6. Nuclear modification of electron spectra and implications for heavy quark energy loss in Au+Au collisions at [FORMULA: SEE TEXT].

    PubMed

    Adler, S S; Afanasiev, S; Aidala, C; Ajitanand, N N; Akiba, Y; Alexander, J; Amirikas, R; Aphecetche, L; Aronson, S H; Averbeck, R; Awes, T C; Azmoun, R; Babintsev, V; Baldisseri, A; Barish, K N; Barnes, P D; Bassalleck, B; Bathe, S; Batsouli, S; Baublis, V; Bazilevsky, A; Belikov, S; Berdnikov, Y; Bhagavatula, S; Boissevain, J G; Borel, H; Borenstein, S; Brooks, M L; Brown, D S; Bruner, N; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J M; Butsyk, S; Camard, X; Chai, J-S; Chand, P; Chang, W C; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choi, I J; Choi, J; Choudhury, R K; Chujo, T; Cianciolo, V; Cobigo, Y; Cole, B A; Constantin, P; d'Enterria, D; David, G; Delagrange, H; Denisov, A; Deshpande, A; Desmond, E J; Devismes, A; Dietzsch, O; Drapier, O; Drees, A; du Rietz, R; Durum, A; Dutta, D; Efremenko, Y V; Egdemir, J; El Chenawi, K; Enokizono, A; En'yo, H; Esumi, S; Ewell, L; Fields, D E; Fleuret, F; Fokin, S L; Fox, B D; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fung, S-Y; Garpman, S; Ghosh, T K; Glenn, A; Gogiberidze, G; Gonin, M; Gosset, J; Goto, Y; Granier de Cassagnac, R; Grau, N; Greene, S V; Grosse Perdekamp, M; Guryn, W; Gustafsson, H-A; Hachiya, T; Haggerty, J S; Hamagaki, H; Hansen, A G; Hartouni, E P; Harvey, M; Hayano, R; Hayashi, N; He, X; Heffner, M; Hemmick, T K; Heuser, J M; Hibino, M; Hill, J C; Holzmann, W; Homma, K; Hong, B; Hoover, A; Ichihara, T; Ikonnikov, V V; Imai, K; Isenhower, D; Ishihara, M; Issah, M; Isupov, A; Jacak, B V; Jang, W Y; Jeong, Y; Jia, J; Jinnouchi, O; Johnson, B M; Johnson, S C; Joo, K S; Jouan, D; Kametani, S; Kamihara, N; Kang, J H; Kapoor, S S; Katou, K; Kelly, S; Khachaturov, B; Khanzadeev, A; Kikuchi, J; Kim, D H; Kim, D J; Kim, D W; Kim, E; Kim, G-B; Kim, H J; Kistenev, E; Kiyomichi, A; Kiyoyama, K; Klein-Boesing, C; Kobayashi, H; Kochenda, L; Kochetkov, V; Koehler, D; Kohama, T; Kopytine, M; Kotchetkov, D; Kozlov, A; Kroon, P J; Kuberg, C H; Kurita, K; Kuroki, Y; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Ladygin, V; Lajoie, J G; Lebedev, A; Leckey, S; Lee, D M; Lee, S; Leitch, M J; Li, X H; Lim, H; Litvinenko, A; Liu, M X; Liu, Y; Maguire, C F; Makdisi, Y I; Malakhov, A; Manko, V I; Mao, Y; Martinez, G; Marx, M D; Masui, H; Matathias, F; Matsumoto, T; McGaughey, P L; Melnikov, E; Messer, F; Miake, Y; Milan, J; Miller, T E; Milov, A; Mioduszewski, S; Mischke, R E; Mishra, G C; Mitchell, J T; Mohanty, A K; Morrison, D P; Moss, J M; Mühlbacher, F; Mukhopadhyay, D; Muniruzzaman, M; Murata, J; Nagamiya, S; Nagle, J L; Nakamura, T; Nandi, B K; Nara, M; Newby, J; Nilsson, P; Nyanin, A S; Nystrand, J; O'Brien, E; Ogilvie, C A; Ohnishi, H; Ojha, I D; Okada, K; Ono, M; Onuchin, V; Oskarsson, A; Otterlund, I; Oyama, K; Ozawa, K; Pal, D; Palounek, A P T; Pantuev, V; Papavassiliou, V; Park, J; Parmar, A; Pate, S F; Peitzmann, T; Peng, J-C; Peresedov, V; Pinkenburg, C; Pisani, R P; Plasil, F; Purschke, M L; Purwar, A K; Rak, J; Ravinovich, I; Read, K F; Reuter, M; Reygers, K; Riabov, V; Riabov, Y; Roche, G; Romana, A; Rosati, M; Rosnet, P; Ryu, S S; Sadler, M E; Saito, N; Sakaguchi, T; Sakai, M; Sakai, S; Samsonov, V; Sanfratello, L; Santo, R; Sato, H D; Sato, S; Sawada, S; Schutz, Y; Semenov, V; Seto, R; Shaw, M R; Shea, T K; Shibata, T-A; Shigaki, K; Shiina, T; Silva, C L; Silvermyr, D; Sim, K S; Singh, C P; Singh, V; Sivertz, M; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Staley, F; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Sullivan, J P; Takagui, E M; Taketani, A; Tamai, M; Tanaka, K H; Tanaka, Y; Tanida, K; Tannenbaum, M J; Tarján, P; Tepe, J D; Thomas, T L; Tojo, J; Torii, H; Towell, R S; Tserruya, I; Tsuruoka, H; Tuli, S K; Tydesjö, H; Tyurin, N; van Hecke, H W; Velkovska, J; Velkovsky, M; Veszprémi, V; Villatte, L; Vinogradov, A A; Volkov, M A; Vznuzdaev, E; Wang, X R; Watanabe, Y; White, S N; Wohn, F K; Woody, C L; Xie, W; Yang, Y; Yanovich, A; Yokkaichi, S; Young, G R; Yushmanov, I E; Zajc, W A; Zhang, C; Zhou, S; Zhou, S J; Zolin, L

    2006-01-27

    The PHENIX experiment has measured midrapidity ([FORMULA: SEE TEXT]) transverse momentum spectra ([FORMULA: SEE TEXT]) of electrons as a function of centrality in Au+Au collisions at [FORMULA: SEE TEXT]. Contributions from photon conversions and from light hadron decays, mainly Dalitz decays of pi0 and eta mesons, were removed. The resulting nonphotonic electron spectra are primarily due to the semileptonic decays of hadrons carrying heavy quarks. Nuclear modification factors were determined by comparison to nonphotonic electrons in p+p collisions. A significant suppression of electrons at high pT is observed in central Au+Au collisions, indicating substantial energy loss of heavy quarks. PMID:16486687

  7. Fast and high-fidelity optical initialization of spin state of an electron in a semiconductor quantum dot using light-hole-trion states

    NASA Astrophysics Data System (ADS)

    Kumar, Parvendra; Nakajima, Takashi

    2016-07-01

    We theoretically show that under the Faraday geometry fast and high-fidelity optical initialization of electron spin (ES) state in a semiconductor quantum dot (SQD) can be realized by utilizing the light-hole (LH)-trion states. Initialization is completed within the time scale of ten nanoseconds with high fidelity, and the initialization laser pulse can be linearly, right-circularly, or left-circularly polarized. Moreover, we demonstrate that the time required for initialization can be further shortened down to a few hundreds of picoseconds if we introduce a pillar-microcavity to promote the relaxation of a LH-trion state towards the desired ES state through the Purcell effect. We also clarify the role of heavy-hole and light-hole mixing induced transitions on the fidelity of ES state initialization.

  8. Kinetic and electron-electron energies for convex sums of ground state densities with degeneracies and fractional electron number

    SciTech Connect

    Levy, Mel E-mail: mlevy@tulane.edu; Anderson, James S. M.; Zadeh, Farnaz Heidar; Ayers, Paul W. E-mail: mlevy@tulane.edu

    2014-05-14

    Properties of exact density functionals provide useful constraints for the development of new approximate functionals. This paper focuses on convex sums of ground-level densities. It is observed that the electronic kinetic energy of a convex sum of degenerate ground-level densities is equal to the convex sum of the kinetic energies of the individual degenerate densities. (The same type of relationship holds also for the electron-electron repulsion energy.) This extends a known property of the Levy-Valone Ensemble Constrained-Search and the Lieb Legendre-Transform refomulations of the Hohenberg-Kohn functional to the individual components of the functional. Moreover, we observe that the kinetic and electron-repulsion results also apply to densities with fractional electron number (even if there are no degeneracies), and we close with an analogous point-wise property involving the external potential. Examples where different degenerate states have different kinetic energy and electron-nuclear attraction energy are given; consequently, individual components of the ground state electronic energy can change abruptly when the molecular geometry changes. These discontinuities are predicted to be ubiquitous at conical intersections, complicating the development of universally applicable density-functional approximations.

  9. Spectrum, radial wave functions, and hyperfine splittings of the Rydberg states in heavy alkali-metal atoms

    NASA Astrophysics Data System (ADS)

    Sanayei, Ali; Schopohl, Nils

    2016-07-01

    We present numerically accurate calculations of the bound-state spectrum of the highly excited valence electron in the heavy alkali-metal atoms solving the radial Schrödinger eigenvalue problem with a modern spectral collocation method that applies also for a large principal quantum number n ≫1 . As an effective single-particle potential we favor the reputable potential of Marinescu et al. [Phys. Rev. A 49, 982 (1994)], 10.1103/PhysRevA.49.982. Recent quasiclassical calculations of the quantum defect of the valence electron agree for orbital angular momentum l =0 ,1 ,2 ,... overall remarkably well with the results of the numerical calculations, but for the Rydberg states of rubidium and also cesium with l =3 this agreement is less fair. The reason for this anomaly is that in rubidium and cesium the potential acquires for l =3 deep inside the ionic core a second classical region, thus invalidating a standard Wentzel-Kramers-Brillouin (WKB) calculation with two widely spaced turning points. Comparing then our numerical solutions of the radial Schrödinger eigenvalue problem with the uniform analytic WKB approximation of Langer constructed around the remote turning point rn,j ,l (" close=")n -δ0)">+ we observe everywhere a remarkable agreement, apart from a tiny region around the inner turning point rn,j ,l (-). For s states the centrifugal barrier is absent and no inner turning point exists: rn,j ,0 (-)=0 . With the help of an ansatz proposed by Fock we obtain for the s states a second uniform analytic approximation to the radial wave function complementary to the WKB approximation of Langer, which is exact for r →0+ . From the patching condition, that is, for l =0 the Langer and Fock solutions should agree in the intermediate region 0

  10. Steady-state and transitional aerodynamic characteristics of a wing in simulated heavy rain

    NASA Technical Reports Server (NTRS)

    Campbell, Bryan A.; Bezos, Gaudy M.

    1989-01-01

    The steady-state and transient effects of simulated heavy rain on the subsonic aerodynamic characteristics of a wing model were determined in the Langley 14- by 22-Foot Subsonic Tunnel. The 1.29 foot chord wing was comprised of a NACA 23015 airfoil and had an aspect ratio of 6.10. Data were obtained while test variables of liquid water content, angle of attack, and trailing edge flap angle were parametrically varied at dynamic pressures of 10, 30, and 50 psf (i.e., Reynolds numbers of .76x10(6), 1.31x10(6), and 1.69x10(6)). The experimental results showed reductions in lift and increases in drag when in the simulated rain environment. Accompanying this was a reduction of the stall angle of attack by approximately 4 deg. The transient aerodynamic performance during transition from dry to wet steady-state conditions varied between a linear and a nonlinear transition.

  11. Dynamics and spectroscopy of CH₂OO excited electronic states.

    PubMed

    Kalinowski, Jaroslaw; Foreman, Elizabeth S; Kapnas, Kara M; Murray, Craig; Räsänen, Markku; Gerber, R Benny

    2016-04-28

    The excited states of the Criegee intermediate CH2OO are studied in molecular dynamics simulations using directly potentials from multi-reference perturbation theory (MR-PT2). The photoexcitation of the species is simulated, and trajectories are propagated in time on the excited state. Some of the photoexcitation events lead to direct fragmentation of the molecule, but other trajectories describe at least several vibrations in the excited state, that may terminate by relaxation to the ground electronic state. Limits on the role of non-adiabatic contributions to the process are estimated by two different simulations, one that forces surface-hopping at potential crossings, and another that ignores surface hopping altogether. The effect of non-adiabatic transitions is found to be small. Spectroscopic implications and consequences for the interpretation of experimental results are discussed. PMID:27040614

  12. Electron teleportation via Majorana bound states in a mesoscopic superconductor.

    PubMed

    Fu, Liang

    2010-02-01

    Zero-energy Majorana bound states in superconductors have been proposed to be potential building blocks of a topological quantum computer, because quantum information can be encoded nonlocally in the fermion occupation of a pair of spatially separated Majorana bound states. However, despite intensive efforts, nonlocal signatures of Majorana bound states have not been found in charge transport. In this work, we predict a striking nonlocal phase-coherent electron transfer process by virtue of tunneling in and out of a pair of Majorana bound states. This teleportation phenomenon only exists in a mesoscopic superconductor because of an all-important but previously overlooked charging energy. We propose an experimental setup to detect this phenomenon in a superconductor-quantum-spin-Hall-insulator-magnetic-insulator hybrid system. PMID:20366777

  13. Understanding x-ray driven impulsive electronic state redistribution using a three-state model

    NASA Astrophysics Data System (ADS)

    Ware, Matthew R.; Cryan, James; Bucksbaum, Philip H.

    2016-05-01

    The natural timescale for electron motion is extremely fast; electrons can move across molecular bonds in less than a femtosecond. To understand this fast motion and the role of electronic coherence, we are interested in creating a superposition of valence excited states through excitation with a broad bandwidth (>5eV) laser pulse. In the x-ray regime, the molecular ground state can couple to valence-excited states through an intermediate autoionizing resonance in a process known as stimulated x-ray Raman scattering (SXRS). X-rays excite electrons from the highly localized K-shells in a molecule, creating a superposition of valence-excited states initially localized around a target atom in the molecule. Coherences between states in the superposition will subsequently drive charge transfer as the wavepacket spreads out across the molecule. We use an effective 3-state model coupling the ground, auto-ionizing, and valence-excited states in diatomic systems to study the cross-section of SXRS as function of x-ray intensity, central frequency, bandwidth, and chirp. We also make observations on how the x-ray parameters affect the degree of initial localization to an atom of the wavepacket created in SXRS. This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division.

  14. Sun-to-Earth Analysis of Heavy Ion Charge States and Solar Wind Properties in Pseudo Streamers

    NASA Astrophysics Data System (ADS)

    Oran, R.; van der Holst, B.; Landi, E.; Gombosi, T. I.

    2013-12-01

    Coronal pseudo-streamers constitute a distinct type of magnetic structures, relatively less understood compared to helmet streamers and coronal holes. Studying the plasma dynamics in pseudo-streamers opens up an additional window into the larger problems of coronal heating and solar wind acceleration. Pseudo-streamers do not necessarily possess the low densities observed in coronal holes, making them almost indistinguishable from their surroundings in remote images of the corona. Thus locating pseudo-streamers requires a realistic 3D model of the magnetic field. In this work, we present results from the Alfven Wave Solar Model (AWSoM), a 3D magnetohydrodynamic model extending from the top of the chromosphere to 1AU, combined with a charge state evolution model (Michigan Ionization Code) for heavy ions. The MHD model is driven by Alfvenic turbulence, which is the sole source of heating, and is constrained by the observed photospheric magnetic field. The 3D nature of the MHD solution allows us to connect the plasma at any point at 1AU to its origin on the solar surface. We can then identify the coronal foot-point of a pseudo-streamer as well as its signature in in-situ observations at 1AU. The speed, electron temperature and density distribution along the selected magnetic field lines are extracted from the MHD solution and used as input to the charge state evolution model. The predicted charge state distribution will be used study the pseudo-streamer in two ways. First, the predicted frozen-in charge state distribution can be directly compared to in-situ measurements in the heliosphere made by the SWICS instrument on board ACE and Ulysses. Second, the charge state values predicted in the inner corona (below 1.5 solar radii) can be combined with the CHIANTI database and the 3D model's temperature and density distributions to calculate spectra line intensities and narrow-band images along any line of sight, to be compared with observations from SOHO, STEREO, Hinode

  15. Low-lying electronic states of LiF molecule with inner electrons correlation

    NASA Astrophysics Data System (ADS)

    Wan, Ming-jie; Huang, Duo-hui; Yang, Jun-sheng; Cao, Qi-long; Jin, Cheng-guo; Wang, Fan-hou

    2015-06-01

    The potential energy curves and dipole moments of the low-lying electronic states of LiF molecule are performed by using highly accurate multi-reference configuration interaction with Awcv5z basis sets. 1s, the inner shell of Li is considered as the closed orbit, which is used to characterise the spectroscopic properties of a manifold of singlet and triplet states. 16 electronic states correlate with two lowest dissociation channels Li(2S)+F(2P) and Li(2P)+F(2P) are investigated. Spectroscopic parameters of the ground state X1Σ+ have been evaluated and critically compared with the available experimental values and the other theoretical data. However, spectroscopic parameters of 13Π, 11Δ, 11Σ-, 11Π, 13Σ+, 23Σ+, 13Δ, 13Σ-, 23Π, 21Π, 33Π, 31Π and 33Σ+ states are studied for the first time. These 13 excited states have shallow potential wells, and the dispersion coefficients of these excited states are predicted. In additional, oscillator strengths of excited states at equilibrium distances are also predicted.

  16. Localized Electron States Near a Metal-SemiconductorNanocontact

    SciTech Connect

    Demchenko, Denis O.; Wang, Lin-Wang

    2007-04-25

    The electronic structure of nanowires in contact withmetallic electrodes of experimentally relevant sizes is calculated byincorporating the electrostatic polarization potential into the atomisticsingle particle Schrodinger equation. We show that the presence of anelectrode produces localized electron/hole states near the electrode, aphenomenon only exhibited in nanostructures and overlooked in the past.This phenomenon will have profound implications on electron transport insuch nanosystems. We calculate several electrode/nanowire geometries,with varying contact depths and nanowire radii. We demonstrate the changein the band gap of up to 0.5 eV in 3 nm diameter CdSe nanowires andcalculate the magnitude of the applied electric field necessary toovercome the localization.

  17. 77 FR 50502 - California State Nonroad Engine Pollution Control Standards; In-Use Heavy-Duty Vehicles (As...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-21

    .... \\2\\ 59 FR 36969 (July 20, 1994). \\3\\ See 62 FR 67733 (December 30, 1997). The applicable regulations... the California standard. \\4\\ See 59 FR 36969 (July 20, 1994). In order to be consistent with section... AGENCY California State Nonroad Engine Pollution Control Standards; In- Use Heavy-Duty Vehicles...

  18. Topological states of non-Dirac electrons on a triangular lattice

    NASA Astrophysics Data System (ADS)

    Liang, Qi-Feng; Yu, Rui; Zhou, Jian; Hu, Xiao

    2016-01-01

    We demonstrate possible nontrivial topology of non-Dirac electrons. In particular we show that, because of the C3 crystal symmetry and time-reversal symmetry, multiple p orbitals accommodated on a triangular lattice exhibit a degeneracy and quadratic non-Dirac band dispersions at the Γ point. When the atomic spin-orbit coupling (SOC) is taken into account, a quantum spin Hall effect state is realized. As revealed explicitly by a k .p model, the nontrivial topology is associated with a meron structure with double vorticity in the pseudospin texture, a mechanism different from that on honeycomb lattice and the band inversion. One possible realization of this scheme is the Si[111] surface adapted by heavy elements with strong atomic SOC, with symmetry and orbitals selected by choosing coverage and auxiliary elements. In terms of first-principles calculations on 1/3 regular coverage of Bi a topological gap of ˜0.15 eV is derived.

  19. Mapping the Electronic States of One Dimensional Peapod Structures

    NASA Astrophysics Data System (ADS)

    Hornbaker, D. J.

    2003-03-01

    A key issue of potential technological importance is how the electronic properties of single wall carbon nanotubes are altered by their interactions with other molecules. We address this question by examining the properties of carbon heterostructures formed by the encapsulation of C_60 molecules within the hollow interiors of single wall nanotubes.^1 We study the properties of these novel macromolecules (dubbed 'peapods') using a low temperature, ultra-high vacuum scanning tunneling microscope (STM). Our experiments reveal that while no discernable change in the atomic structure of the encapsulating nanotubes is evident, the presence of interior C_60 molecules can dramatically affect the electronic structure of the nanotube cage. Constant current STM images of peapods display pronounced spatial modulation of the electronic density at sample biases greater than 1V, with a periodicity consistent with the intermolecular spacing of close-packed C_60 molecules inside the nanotube. This effect has been observed on peapods displaying both semiconducting and metallic densities of states. Coincident with this modulation is the appearance of characteristic features in the electronic band structure measured via tunneling spectroscopy. Theoretical modeling^2,3 indicates these features arise from coupling between the valence states of the encapsulated fullerenes, leading to the formation of a hybrid electronic band. Our experiments demonstrate that encapsulation of molecules is a viable route for selectively altering the electronic properties of carbon nanotubes. ^1B.W. Smith and D.E. Luzzi, Chem. Phys. Lett. 321, 169 (2000). ^2D.J. Hornbaker et al. Science 295, 828 (2002). ^3C. Kane et al. Phys. Rev. B (submitted).

  20. Minimal-excitation states for electron quantum optics using levitons

    NASA Astrophysics Data System (ADS)

    Dubois, J.; Jullien, T.; Portier, F.; Roche, P.; Cavanna, A.; Jin, Y.; Wegscheider, W.; Roulleau, P.; Glattli, D. C.

    2013-10-01

    The on-demand generation of pure quantum excitations is important for the operation of quantum systems, but it is particularly difficult for a system of fermions. This is because any perturbation affects all states below the Fermi energy, resulting in a complex superposition of particle and hole excitations. However, it was predicted nearly 20 years ago that a Lorentzian time-dependent potential with quantized flux generates a minimal excitation with only one particle and no hole. Here we report that such quasiparticles (hereafter termed levitons) can be generated on demand in a conductor by applying voltage pulses to a contact. Partitioning the excitations with an electronic beam splitter generates a current noise that we use to measure their number. Minimal-excitation states are observed for Lorentzian pulses, whereas for other pulse shapes there are significant contributions from holes. Further identification of levitons is provided in the energy domain with shot-noise spectroscopy, and in the time domain with electronic Hong-Ou-Mandel noise correlations. The latter, obtained by colliding synchronized levitons on a beam splitter, exemplifies the potential use of levitons for quantum information: using linear electron quantum optics in ballistic conductors, it is possible to imagine flying-qubit operation in which the Fermi statistics are exploited to entangle synchronized electrons emitted by distinct sources. Compared with electron sources based on quantum dots, the generation of levitons does not require delicate nanolithography, considerably simplifying the circuitry for scalability. Levitons are not limited to carrying a single charge, and so in a broader context n-particle levitons could find application in the study of full electron counting statistics. But they can also carry a fraction of charge if they are implemented in Luttinger liquids or in fractional quantum Hall edge channels; this allows the study of Abelian and non-Abelian quasiparticles in the

  1. Electronic and ground state properties of ThTe

    NASA Astrophysics Data System (ADS)

    Bhardwaj, Purvee; Singh, Sadhna

    2016-05-01

    The electronic properties of ThTe in cesium chloride (CsCl, B2) structure are investigated in the present paper. To study the ground state properties of thorium chalcogenide, the first principle calculations have been calculated. The bulk properties, including lattice constant, bulk modulus and its pressure derivative are obtained. The calculated equilibrium structural parameters are in good agreement with the available experimental and theoretical results.

  2. Differential conductance and defect states in the heavy-fermion superconductor CeCoIn5

    NASA Astrophysics Data System (ADS)

    Van Dyke, John S.; Davis, J. C. Séamus; Morr, Dirk K.

    2016-01-01

    We demonstrate that the electronic band structure extracted from quasiparticle interference spectroscopy [Nat. Phys. 9, 468 (2013), 10.1038/nphys2671] and the theoretically computed form of the superconducting gaps [Proc. Natl. Acad. Sci. USA 111, 11663 (2014), 10.1073/pnas.1409444111] can be used to understand the d I /d V line shape measured in the normal and superconducting state of CeCoIn5 [Nat. Phys. 9, 474 (2013), 10.1038/nphys2672]. In particular, the d I /d V line shape, and the spatial structure of defect-induced impurity states, reflects the existence of multiple superconducting gaps of dx2-y2 symmetry. These results strongly support a recently proposed microscopic origin of the unconventional superconducting state.

  3. Differential conductance and defect states in the heavy-fermion superconductor CeCoIn5

    DOE PAGESBeta

    John S. Van Dyke; Davis, James C.; Morr, Dirk K.

    2016-01-22

    We demonstrate that the electronic band structure extracted from quasiparticle interference spectroscopy [Nat. Phys. 9, 468 (2013)] and the theoretically computed form of the superconducting gaps [Proc. Natl. Acad. Sci. USA 111, 11663 (2014)] can be used to understand the dI/dV line shape measured in the normal and superconducting state of CeCoIn5 [Nat. Phys. 9, 474 (2013)]. In particular, the dI/dV line shape, and the spatial structure of defect-induced impurity states, reflects the existence of multiple superconducting gaps of dx2–y2 symmetry. As a result, these results strongly support a recently proposed microscopic origin of the unconventional superconducting state.

  4. Liquid-state polaron theory of the hydrated electron revisited

    NASA Astrophysics Data System (ADS)

    Donley, James P.; Heine, David R.; Tormey, Caleb A.; Wu, David T.

    2014-07-01

    The quantum path integral/classical liquid-state theory of Chandler and co-workers, created to describe an excess electron in solvent, is re-examined for the hydrated electron. The portion that models electron-water density correlations is replaced by two equations: the range optimized random phase approximation (RO-RPA), and the Donley, Rajasekaran, and Liu (DRL) approximation to the "two-chain" equation, both shown previously to describe accurately the static structure and thermodynamics of strongly charged polyelectrolyte solutions. The static equilibrium properties of the hydrated electron are analyzed using five different electron-water pseudopotentials. The theory is then compared with data from mixed quantum/classical Monte Carlo and molecular dynamics simulations using these same pseudopotentials. It is found that the predictions of the RO-RPA and DRL-based polaron theories are similar and improve upon previous theory, with values for almost all properties analyzed in reasonable quantitative agreement with the available simulation data. Also, it is found using the Larsen, Glover, and Schwartz pseudopotential that the theories give values for the solvation free energy that are at least three times larger than that from experiment.

  5. Liquid-state polaron theory of the hydrated electron revisited

    SciTech Connect

    Donley, James P.; Heine, David R.; Tormey, Caleb A.; Wu, David T.

    2014-07-14

    The quantum path integral/classical liquid-state theory of Chandler and co-workers, created to describe an excess electron in solvent, is re-examined for the hydrated electron. The portion that models electron-water density correlations is replaced by two equations: the range optimized random phase approximation (RO-RPA), and the Donley, Rajasekaran, and Liu (DRL) approximation to the “two-chain” equation, both shown previously to describe accurately the static structure and thermodynamics of strongly charged polyelectrolyte solutions. The static equilibrium properties of the hydrated electron are analyzed using five different electron-water pseudopotentials. The theory is then compared with data from mixed quantum/classical Monte Carlo and molecular dynamics simulations using these same pseudopotentials. It is found that the predictions of the RO-RPA and DRL-based polaron theories are similar and improve upon previous theory, with values for almost all properties analyzed in reasonable quantitative agreement with the available simulation data. Also, it is found using the Larsen, Glover, and Schwartz pseudopotential that the theories give values for the solvation free energy that are at least three times larger than that from experiment.

  6. Nuclear Magnetic Resonance in the Superconducting States of Two Heavy Fermion Superconductors, Cerium Dicopper - and URANIUM-BERYLLIUM(13)

    NASA Astrophysics Data System (ADS)

    Tien, Cheng

    Nuclear magnetic resonance (NMR) experiments have been carried out in two heavy fermion superconductors, CeCu(,2)Si(,2) and U(,1-x)Th(,x)Be(,13) (x = 0, 0.0331). The unusual normal-state and superconducting state behavior of CeCu(,2)SDi(,2) and UBe(,13) has recently been discovered. Both compounds exhibit enormous values of the normal-state low -temperature magnetic susceptibility (chi) and the linear specific heat coefficient (gamma). Standard analyses of (chi) and (gamma) result in a two order of magnitude enhancement of the conduction-electron mass, but the ratio (chi)/(gamma) retains a value appropriate to a free-electron gas. It is of interest to obtain as much microscopic information as possible. In one of our CeCu(,2)Si(,2) superconducting specimens, the observed temperature dependence of the spin-lattice relaxation rate 1/T(,1) (T) is consistent with a conventional quasiparticle excitation spectrum below the superconducting transition temperature T(,c). In the other superconducting CeCu(,2)Si(,2) sample, the nuclear spin-lattice relaxation rate decreases drastically just below T(,c) without the apparent enhancement observed in the first sample. This lack of enhancement in 1/T(,1) (T) suggests that the superconductivity in CeCu(,2)Si(,2) is not due to a conventional mechanism. Some unusual features in 1/T(,1) (T) between T(,c) and 1.2 K appear to signal a phase transition, possibly structural in nature. NQR measurements of the nonsuperconducting CeCu(,2)Si(,2) sample are consistent with extensive disorder in the Cu site occupation. The spin-lattice relaxation rate in UBe(,13) varies approximately as T('3) well below the transition temperature T(,c). This behavior is consistent with a class of anisotropic pairing models for which the superconducting gap vanishes along lines on the Fermi surface. Two phase transitions have been observed in the specific heat measurements of U(,0.9669)Th(,0.0331)Be(,13) at T(,c1) and T(,c2). For T(,c2) < T < T(,c1), 1/T(,1

  7. Two electronic states and state exchange time control in spherical nanolayer

    NASA Astrophysics Data System (ADS)

    Aghekyan, N. G.; Kazaryan, E. M.; Kostanyan, A. A.; Sarkisyan, H. A.

    2011-09-01

    Two electronic states in impenetrable spherical quantum nanolayer are discussed. The Coulomb interaction between the electrons is considered as perturbation. The problem is discussed within the frameworks of Russell-Saunders coupling scheme, that is, the spin-orbit interaction is neglected. For this system the analogue of helium atom theory is represented. The dependence of the Coulomb interaction energy of the two electronic system is obtained both upon inner and outer radiuses of the studied nanolayer. The exchange interaction in the spherical nanolayer helium atom and its dependence upon the geometrical parameters of the nanolayer are investigated. It is shown that the exchange time of two electron states could be controlled via changing the geometrical parameters of the nanolayer.

  8. 75 FR 3463 - Cross-Media Electronic Reporting Rule State Authorized Program Revision Approval: State of North...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-21

    ..., the final Cross-Media Electronic Reporting Rule (CROMERR) was published in the Federal Register (70 FR... AGENCY Cross-Media Electronic Reporting Rule State Authorized Program Revision Approval: State of North...'s approval, under regulations for Cross-Media Electronic Reporting, of the State of North...

  9. Proceedings of RIKEN BNL Research Center Workshop entitled Hydrodynamics in Heavy Ion Collisions and QCD Equation of State (Volume 88)

    SciTech Connect

    Karsch,F.; Kharzeev, D.; Molnar, K.; Petreczky, P.; Teaney, D.

    2008-04-21

    The interpretation of relativistic heavy-ion collisions at RHIC energies with thermal concepts is largely based on the relative success of ideal (nondissipative) hydrodynamics. This approach can describe basic observables at RHIC, such as particle spectra and momentum anisotropies, fairly well. On the other hand, recent theoretical efforts indicate that dissipation can play a significant role. Ideally viscous hydrodynamic simulations would extract, if not only the equation of state, but also transport coefficients from RHIC data. There has been a lot of progress with solving relativistic viscous hydrodynamics. There are already large uncertainties in ideal hydrodynamics calculations, e.g., uncertainties associated with initial conditions, freezeout, and the simplified equations of state typically utilized. One of the most sensitive observables to the equation of state is the baryon momentum anisotropy, which is also affected by freezeout assumptions. Up-to-date results from lattice quantum chromodynamics on the transition temperature and equation of state with realistic quark masses are currently available. However, these have not yet been incorporated into the hydrodynamic calculations. Therefore, the RBRC workshop 'Hydrodynamics in Heavy Ion Collisions and QCD Equation of State' aimed at getting a better understanding of the theoretical frameworks for dissipation and near-equilibrium dynamics in heavy-ion collisions. The topics discussed during the workshop included techniques to solve the dynamical equations and examine the role of initial conditions and decoupling, as well as the role of the equation of state and transport coefficients in current simulations.

  10. Squeezed states of electrons and transitions of the density of states

    NASA Technical Reports Server (NTRS)

    Lee, Seung Joo; Um, Chung IN

    1993-01-01

    Electron systems which have low dimensional properties have been constructed by squeezing the motion in zero, one, or two-directions. An isolated quantum dot is modeled by a potential box with delta-profiled, penetrable potential walls embedded in a large outer box with infinitely high potential walls which represent the world function with respect to vacuum. We show the smooth crossover of the density of states from the three-dimensional to the quasi-zero dimensional electron gas.

  11. Low-Lying Electronic States of CuAu.

    PubMed

    Alizadeh Sanati, Davood; Andrae, Dirk

    2016-07-28

    Coinage metal diatomic molecules are building blocks for nanostructured materials, electronic devices, and catalytically or photochemically active systems that are currently receiving lively interest in both fundamental and applied research. The theoretical study presented here elucidates the electronic structure in the ground and several low-lying excited states of the diatomic molecule CuAu that result from the combination of the atoms in their ground states nd(10)(n + 1)s(1 2)S and lowest excited d-hole states nd(9)(n + 1)s(2 2)D (n = 3 for Cu, n = 5 for Au). Full and smooth potential energy curves, obtained at the multireference configuration interaction (MRCI) level of theory, are presented for the complete set of the thus resulting 44 Λ-S terms and 86 Ω terms. Our approach is based on a scalar relativistic description using the Douglas-Kroll-Hess (DKH) Hamiltonian, with subsequent perturbative inclusion of spin-orbit (SO) coupling via the spin-orbit terms of the Breit-Pauli (BP) Hamiltonian. The Ω terms span an energy interval of about 7 eV at the ground state's equilibrium distance. Spectroscopic constants, calculated for all terms, are shown to accurately reproduce the observation for those nine terms that are experimentally known. PMID:27379475

  12. Mean-field studies of time reversal breaking states in super-heavy nuclei with the Gogny force

    SciTech Connect

    Robledo, L. M.

    2015-10-15

    Recent progress on the description of time reversal breaking (odd mass and multi-quasiparticle excitation) states in super-heavy nuclei within a mean field framework and using several flavors of the Gogny interaction is reported. The study includes ground and excited states in selected odd mass isotopes of nobelium and mendelevium as well as high K isomeric states in {sup 254}No. These are two and four-quasiparticle excitations that are treated in the same self-consistent HFB plus blocking framework as the odd mass states.

  13. The physics and chemistry of heavy fermions.

    PubMed Central

    Fisk, Z; Sarrao, J L; Smith, J L; Thompson, J D

    1995-01-01

    The heavy fermions are a subset of the f-electron intermetallic compounds straddling the magnetic/nonmagnetic boundary. Their low-temperature properties are characterized by an electronic energy scale of order 1-10 K. Among the low-temperature ground states observed in heavy fermion compounds are exotic superconductors and magnets, as well as unusual semiconductors. We review here the current experimental and theoretical understanding of these systems. PMID:11607558

  14. Integral elastic, electronic-state, ionization, and total cross sections for electron scattering with furfural

    NASA Astrophysics Data System (ADS)

    Jones, D. B.; da Costa, R. F.; Varella, M. T. do N.; Bettega, M. H. F.; Lima, M. A. P.; Blanco, F.; García, G.; Brunger, M. J.

    2016-04-01

    We report absolute experimental integral cross sections (ICSs) for electron impact excitation of bands of electronic-states in furfural, for incident electron energies in the range 20-250 eV. Wherever possible, those results are compared to corresponding excitation cross sections in the structurally similar species furan, as previously reported by da Costa et al. [Phys. Rev. A 85, 062706 (2012)] and Regeta and Allan [Phys. Rev. A 91, 012707 (2015)]. Generally, very good agreement is found. In addition, ICSs calculated with our independent atom model (IAM) with screening corrected additivity rule (SCAR) formalism, extended to account for interference (I) terms that arise due to the multi-centre nature of the scattering problem, are also reported. The sum of those ICSs gives the IAM-SCAR+I total cross section for electron-furfural scattering. Where possible, those calculated IAM-SCAR+I ICS results are compared against corresponding results from the present measurements with an acceptable level of accord being obtained. Similarly, but only for the band I and band II excited electronic states, we also present results from our Schwinger multichannel method with pseudopotentials calculations. Those results are found to be in good qualitative accord with the present experimental ICSs. Finally, with a view to assembling a complete cross section data base for furfural, some binary-encounter-Bethe-level total ionization cross sections for this collision system are presented.

  15. Integral elastic, electronic-state, ionization, and total cross sections for electron scattering with furfural.

    PubMed

    Jones, D B; da Costa, R F; Varella, M T do N; Bettega, M H F; Lima, M A P; Blanco, F; García, G; Brunger, M J

    2016-04-14

    We report absolute experimental integral cross sections (ICSs) for electron impact excitation of bands of electronic-states in furfural, for incident electron energies in the range 20-250 eV. Wherever possible, those results are compared to corresponding excitation cross sections in the structurally similar species furan, as previously reported by da Costa et al. [Phys. Rev. A 85, 062706 (2012)] and Regeta and Allan [Phys. Rev. A 91, 012707 (2015)]. Generally, very good agreement is found. In addition, ICSs calculated with our independent atom model (IAM) with screening corrected additivity rule (SCAR) formalism, extended to account for interference (I) terms that arise due to the multi-centre nature of the scattering problem, are also reported. The sum of those ICSs gives the IAM-SCAR+I total cross section for electron-furfural scattering. Where possible, those calculated IAM-SCAR+I ICS results are compared against corresponding results from the present measurements with an acceptable level of accord being obtained. Similarly, but only for the band I and band II excited electronic states, we also present results from our Schwinger multichannel method with pseudopotentials calculations. Those results are found to be in good qualitative accord with the present experimental ICSs. Finally, with a view to assembling a complete cross section data base for furfural, some binary-encounter-Bethe-level total ionization cross sections for this collision system are presented. PMID:27083717

  16. Electronic excited states and relaxation dynamics in polymer heterojunction systems

    NASA Astrophysics Data System (ADS)

    Ramon, John Glenn Santos

    , we examine the effect of the nanoscale interfacial morphology and solvation on the electronic excited states of TFB/F8BT. Here, we employ time-dependent density functional theory (TD-DFT) to investigate the relevant excited states of two stacking configurations. We show that the calculated states agree with the excited states responsible for the experimentally observed emission peaks and that these states are blue shifted relative to those of the isolated chain. Furthermore, slight lateral shifts in the stacking orientation not only shift the excited state energies; more importantly, they alter the nature of these states altogether. Lastly, we see that solvation greatly stabilizes the charge-transfer states.

  17. Projectile energy and atomic number dependence of electron capture from pair production in relativistic heavy ion collisions

    NASA Astrophysics Data System (ADS)

    Belkacem, A.; Gould, Harvey; Feinberg, B.; Bossingham, R.; Meyerhof, W. E.

    1994-10-01

    We report the first measurement of the energy dependence of electron capture from electron-positron pair production in relativistic heavy ion collisions. For a La57+ beam incident on Au, Ag, and Cu targets at energies of 0.405, 0.956, and 1.3 GeV/u we find that the cross sections for capture from pair production and the free pair production process increase with increasing collision energy at similar rates. Combining with uranium data reported previously gives a projectile atomic number dependence for 0.956 GeV/u ions on a Au target of Z6.54+/-0.65p for capture from pair production and Z1.53+/-0.80p for the free pair production process.

  18. Benzonitrile: Electron affinity, excited states, and anion solvation

    NASA Astrophysics Data System (ADS)

    Dixon, Andrew R.; Khuseynov, Dmitry; Sanov, Andrei

    2015-10-01

    We report a negative-ion photoelectron imaging study of benzonitrile and several of its hydrated, oxygenated, and homo-molecularly solvated cluster anions. The photodetachment from the unsolvated benzonitrile anion to the X ˜ 1 A 1 state of the neutral peaks at 58 ± 5 meV. This value is assigned as the vertical detachment energy (VDE) of the valence anion and the upper bound of adiabatic electron affinity (EA) of benzonitrile. The EA of the lowest excited electronic state of benzonitrile, a ˜ 3 A 1 , is determined as 3.41 ± 0.01 eV, corresponding to a 3.35 eV lower bound for the singlet-triplet splitting. The next excited state, the open-shell singlet A ˜ 1 A 1 , is found about an electron-volt above the triplet, with a VDE of 4.45 ± 0.01 eV. These results are in good agreement with ab initio calculations for neutral benzonitrile and its valence anion but do not preclude the existence of a dipole-bound state of similar energy and geometry. The step-wise and cumulative solvation energies of benzonitrile anions by several types of species were determined, including homo-molecular solvation by benzonitrile, hydration by 1-3 waters, oxygenation by 1-3 oxygen molecules, and mixed solvation by various combinations of O2, H2O, and benzonitrile. The plausible structures of the dimer anion of benzonitrile were examined using density functional theory and compared to the experimental observations. It is predicted that the dimer anion favors a stacked geometry capitalizing on the π-π interactions between the two partially charged benzonitrile moieties.

  19. Time course of myosin heavy chain transitions in neonatal rats: importance of innervation and thyroid state

    NASA Technical Reports Server (NTRS)

    Adams, G. R.; McCue, S. A.; Zeng, M.; Baldwin, K. M.

    1999-01-01

    During the postnatal period, rat limb muscles adapt to weight bearing via the replacement of embryonic (Emb) and neonatal (Neo) myosin heavy chains (MHCs) by the adult isoforms. Our aim was to characterize this transition in terms of the six MHC isoforms expressed in skeletal muscle and to determine the importance of innervation and thyroid hormone status on the attainment of the adult MHC phenotype. Neonatal rats were made hypothyroid via propylthiouracil (PTU) injection. In normal and PTU subgroups, leg muscles were unilaterally denervated at 15 days of age. The MHC profiles of plantaris (PLN) and soleus (Sol) muscles were determined at 7, 14, 23, and 30 days postpartum. At day 7, the Sol MHC profile was 55% type I, 30% Emb, and 10% Neo; in the PLN, the pattern was 60% Neo and 25% Emb. By day 30 the Sol and PLN had essentially attained an adult MHC profile in the controls. PTU augmented slow MHC expression in the Sol, whereas in the PLN it markedly repressed IIb MHC by retaining neonatal MHC expression. Denervation blunted the upregulation of IIb in the PLN and of Type I in the Sol and shifted the pattern to greater expression of IIa and IIx MHCs in both muscles. In contrast to previous observations, these findings collectively suggest that both an intact thyroid and innervation state are obligatory for the attainment of the adult MHC phenotype, particularly in fast-twitch muscles.

  20. Gauge invariant description of heavy quark bound states in quantum chromodynamics

    SciTech Connect

    Moore, S.E.

    1980-08-01

    A model for a heavy quark meson is proposed in the framework of a gauge-invariant version of quantum chromodynamics. The field operators in this formulation are taken to be Wilson loops and strings with quark-antiquark ends. The fundamental differential equations of point-like Q.C.D. are expressed as variational equations of the extended loops and strings. The 1/N expansion is described, and it is assumed that nonleading effects such as intermediate quark pairs and nonplanar gluonic terms can be neglected. The action of the Hamiltonian in the A/sub 0/ = 0 gauge on a string operator is derived. A trial meson wave functional is constructed consisting of a path-averaged string operator applied to the full vacuum. A Gaussian in the derivative of the path location is assumed for the minimal form of the measure over paths. A variational parameter is incorporated in the measure as the exponentiated coefficient of the squared path location. The expectation value of the Hamiltonian in the trial state is evaluated for the assumption that the negative logarithm of the expectation value of a Wilson loop is proportional to the loop area. The energy is then minimized by deriving the equivalent quantum mechanical Schroedinger's equation and using the quantum mechanical 1/n expansion to estimate the effective eigenvalues. It is found that the area law behavior of the Wilson loop implies a nonzero best value of the variational parameter corresponding to a quantum broadening of the flux tube.

  1. Search for heavy resonances decaying to two Higgs bosons in final states containing four b quarks

    NASA Astrophysics Data System (ADS)

    Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Erö, J.; Flechl, M.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; König, A.; Krammer, M.; Krätschmer, I.; Liko, D.; Matsushita, T.; Mikulec, I.; Rabady, D.; Rad, N.; Rahbaran, B.; Rohringer, H.; Schieck, J.; Schöfbeck, R.; Strauss, J.; Treberer-Treberspurg, W.; Waltenberger, W.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Alderweireldt, S.; Cornelis, T.; De Wolf, E. A.; Janssen, X.; Knutsson, A.; Lauwers, J.; Luyckx, S.; Van De Klundert, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Abu Zeid, S.; Blekman, F.; D'Hondt, J.; Daci, N.; De Bruyn, I.; Deroover, K.; Heracleous, N.; Keaveney, J.; Lowette, S.; Moortgat, S.; Moreels, L.; Olbrechts, A.; Python, Q.; Strom, D.; Tavernier, S.; Van Doninck, W.; Van Mulders, P.; Van Onsem, G. P.; Van Parijs, I.; Barria, P.; Brun, H.; Caillol, C.; Clerbaux, B.; De Lentdecker, G.; Fasanella, G.; Favart, L.; Goldouzian, R.; Grebenyuk, A.; Karapostoli, G.; Lenzi, T.; Léonard, A.; Maerschalk, T.; Marinov, A.; Perniè, L.; Randle-conde, A.; Seva, T.; Vander Velde, C.; Vanlaer, P.; Yonamine, R.; Zenoni, F.; Zhang, F.; Beernaert, K.; Benucci, L.; Cimmino, A.; Crucy, S.; Dobur, D.; Fagot, A.; Garcia, G.; Gul, M.; Mccartin, J.; Ocampo Rios, A. A.; Poyraz, D.; Ryckbosch, D.; Salva, S.; Sigamani, M.; Tytgat, M.; Van Driessche, W.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Beluffi, C.; Bondu, O.; Brochet, S.; Bruno, G.; Caudron, A.; Ceard, L.; Visscher, S. De; Delaere, C.; Delcourt, M.; Favart, D.; Forthomme, L.; Giammanco, A.; Jafari, A.; Jez, P.; Komm, M.; Lemaitre, V.; Mertens, A.; Musich, M.; Nuttens, C.; Perrini, L.; Piotrzkowski, K.; Popov, A.; Quertenmont, L.; Selvaggi, M.; Vidal Marono, M.; Beliy, N.; Hammad, G. H.; Aldá Júnior, W. L.; Alves, F. L.; Alves, G. A.; Brito, L.; Correa Martins Junior, M.; Hamer, M.; Hensel, C.; Moraes, A.; Pol, M. E.; Rebello Teles, P.; Belchior Batista Das Chagas, E.; Carvalho, W.; Chinellato, J.; Custódio, A.; Da Costa, E. M.; De Jesus Damiao, D.; De Oliveira Martins, C.; Fonseca De Souza, S.; Huertas Guativa, L. M.; Malbouisson, H.; Matos Figueiredo, D.; Mora Herrera, C.; Mundim, L.; Nogima, H.; Prado Da Silva, W. L.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E. J.; Vilela Pereira, A.; Ahuja, S.; Bernardes, C. A.; De Souza Santos, A.; Dogra, S.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Mercadante, P. G.; Moon, C. S.; Novaes, S. F.; Padula, Sandra S.; Romero Abad, D.; Ruiz Vargas, J. C.; Aleksandrov, A.; Hadjiiska, R.; Iaydjiev, P.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Vutova, M.; Dimitrov, A.; Glushkov, I.; Litov, L.; Pavlov, B.; Petkov, P.; Fang, W.; Ahmad, M.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Cheng, T.; Du, R.; Jiang, C. H.; Leggat, D.; Plestina, R.; Romeo, F.; Shaheen, S. M.; Spiezia, A.; Tao, J.; Wang, C.; Wang, Z.; Zhang, H.; Asawatangtrakuldee, C.; Ban, Y.; Li, Q.; Liu, S.; Mao, Y.; Qian, S. J.; Wang, D.; Xu, Z.; Avila, C.; Cabrera, A.; Chaparro Sierra, L. F.; Florez, C.; Gomez, J. P.; Gomez Moreno, B.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Puljak, I.; Ribeiro Cipriano, P. M.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Kadija, K.; Luetic, J.; Micanovic, S.; Sudic, L.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Rykaczewski, H.; Finger, M.; Finger, M.; Assran, Y.; Ellithi Kamel, A.; Mahrous, A.; Radi, A.; Calpas, B.; Kadastik, M.; Murumaa, M.; Raidal, M.; Tiko, A.; Veelken, C.; Eerola, P.; Pekkanen, J.; Voutilainen, M.; Härkönen, J.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Peltola, T.; Tuominiemi, J.; Tuovinen, E.; Wendland, L.; Talvitie, J.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Favaro, C.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Machet, M.; Malcles, J.; Rander, J.; Rosowsky, A.; Titov, M.; Zghiche, A.; Abdulsalam, A.; Antropov, I.; Baffioni, S.; Beaudette, F.; Busson, P.; Cadamuro, L.; Chapon, E.; Charlot, C.; Davignon, O.; Filipovic, N.; Granier de Cassagnac, R.; Jo, M.; Lisniak, S.; Mastrolorenzo, L.; Miné, P.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Ortona, G.; Paganini, P.; Pigard, P.; Regnard, S.; Salerno, R.; Sirois, Y.; Strebler, T.; Yilmaz, Y.; Zabi, A.; Agram, J.-L.; Andrea, J.; Aubin, A.; Bloch, D.; Brom, J.-M.; Buttignol, M.; Chabert, E. C.; Chanon, N.; Collard, C.; Conte, E.; Coubez, X.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Goetzmann, C.; Le Bihan, A.-C.; Merlin, J. A.; Skovpen, K.; Van Hove, P.; Gadrat, S.

    2016-07-01

    A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons ({H}) in proton-proton collisions collected by the CMS experiment at the LHC at √{s}=8 {TeV} . The data correspond to an integrated luminosity of 19.7 {fb}^{-1}. The search considers {H} {H} resonances with masses between 1 and 3 {TeV}, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and {t}overline{{t}} events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95 % confidence level for the product of the production cross section and branching fraction σ ({{g} {g}} → X) B({X} → {H} {H} → {b} overline{{b}} {b} overline{{b}} ) range from 10 to 1.5 { fb} for the mass of X from 1.15 to 2.0 {TeV}, significantly extending previous searches. For a warped extra dimension theory with a mass scale Λ _R = 1 {TeV}, the data exclude radion scalar masses between 1.15 and 1.55 {TeV}.

  2. Semileptonic decays of charmed and beauty baryons with heavy sterile neutrinos in the final state

    SciTech Connect

    Ramazanov, Sabir

    2009-04-01

    We obtain tree-level estimates of various differential branching ratios of heavy baryon decays with massive sterile neutrinos {nu}{sub x} in the final state. Generally, charmed baryons are found to be less promising than charmed mesons, in contrast to b hadrons. In the latter case, branching ratios of beauty mesons and baryons into sterile neutrinos are of the same order. As a consequence, at high energies beauty baryons give contribution to sterile neutrino production comparable to the contribution of beauty mesons (up to about 15%). Experimental limits on active-to-sterile mixing are quite strong for neutrinos lighter than D mesons but for heavier neutrinos they are weaker. As an example, for neutrino masses in the range 2 GeV < or approx. m{sub {nu}{sub x}} < or approx. 2.5 GeV, current data imply that the bounds on {lambda}{sub b}-hyperon branching ratios into sterile neutrinos are Br({lambda}{sub b}{yields}{lambda}{sub c}+e{sup -}+{nu}{sub x}) < or approx. 1.3x10{sup -5}-1.7x10{sup -6} and Br({lambda}{sub b}{yields}{lambda}{sub c}+{mu}{sup -}+{nu}{sub x}) < or approx. 3.9x10{sup -7}-1.4x10{sup -7}.

  3. Constraining supernova equations of state with equilibrium constants from heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Hempel, Matthias; Hagel, Kris; Natowitz, Joseph; Röpke, Gerd; Typel, Stefan

    2015-04-01

    Cluster formation is a fundamental aspect of the equation of state (EOS) of warm and dense nuclear matter such as can be found in supernovae (SNe). Similar matter can be studied in heavy-ion collisions (HICs). We use the experimental data of Qin et al. [Phys. Rev. Lett. 108, 172701 (2012), 10.1103/PhysRevLett.108.172701] to test calculations of cluster formation and the role of in-medium modifications of cluster properties in SN EOSs. For the comparison between theory and experiment we use chemical equilibrium constants as the main observables. This reduces some of the systematic uncertainties and allows deviations from ideal gas behavior to be identified clearly. In the analysis, we carefully account for the differences between matter in SNe and HICs. We find that, at the lowest densities, the experiment and all theoretical models are consistent with the ideal gas behavior. At higher densities ideal behavior is clearly ruled out and interaction effects have to be considered. The contributions of continuum correlations are of relevance in the virial expansion and remain a difficult problem to solve at higher densities. We conclude that at the densities and temperatures discussed mean-field interactions of nucleons, inclusion of all relevant light clusters, and a suppression mechanism of clusters at high densities have to be incorporated in the SN EOS.

  4. Tuning the electronic hybridization in the heavy fermion cage compound YbFe2Zn20 with Cd doping

    NASA Astrophysics Data System (ADS)

    Cabrera-Baez, M.; Ribeiro, R. A.; Avila, M. A.

    2016-09-01

    The tuning of the electronic properties of heavy fermion compounds by chemical substitution provides excellent opportunities for further understanding the physics of hybridized ions in crystal lattices. Here we present an investigation on the effects of Cd doping in flux-grown single crystals of the complex intermetallic cage compound YbFe2Zn20, which has been described as a heavy fermion with a Sommerfeld coefficient of 535 mJ mol‑1 · K‑2. The substitution of Cd for Zn disturbs the system by expanding the unit cell and, in this case, the size of the Zn cages that surround the Yb and Fe. With an increasing amount of Cd, the hybridization between the Yb 4f electrons and the conduction electrons is weakened, as shown by a decrease in the Sommerfeld coefficient, which should be accompanied by a valence shift of the Yb3+ due to the negative chemical pressure effect. This scenario is also supported by the low temperature DC magnetic susceptibility, which is gradually suppressed and shows an increment of the Kondo temperature, based on a shift to higher temperatures of the characteristic broad susceptibility peak. Furthermore, the DC resistivity decreases with the isoelectronic substitution of Cd for Zn, contrary to expectations in an increasingly disordered system, and implying that the valence shift is not related to charge carrier doping. The combined results demonstrate the excellent complementarity between positive physical pressure and negative chemical pressure, and point to a rich playground for exploring the physics and chemistry of strongly correlated electron systems in the general family of Zn20 compounds, despite their structural complexity.

  5. Tuning the electronic hybridization in the heavy fermion cage compound YbFe2Zn20 with Cd doping.

    PubMed

    Cabrera-Baez, M; Ribeiro, R A; Avila, M A

    2016-09-21

    The tuning of the electronic properties of heavy fermion compounds by chemical substitution provides excellent opportunities for further understanding the physics of hybridized ions in crystal lattices. Here we present an investigation on the effects of Cd doping in flux-grown single crystals of the complex intermetallic cage compound YbFe2Zn20, which has been described as a heavy fermion with a Sommerfeld coefficient of 535 mJ mol(-1) · K(-2). The substitution of Cd for Zn disturbs the system by expanding the unit cell and, in this case, the size of the Zn cages that surround the Yb and Fe. With an increasing amount of Cd, the hybridization between the Yb 4f electrons and the conduction electrons is weakened, as shown by a decrease in the Sommerfeld coefficient, which should be accompanied by a valence shift of the Yb(3+) due to the negative chemical pressure effect. This scenario is also supported by the low temperature DC magnetic susceptibility, which is gradually suppressed and shows an increment of the Kondo temperature, based on a shift to higher temperatures of the characteristic broad susceptibility peak. Furthermore, the DC resistivity decreases with the isoelectronic substitution of Cd for Zn, contrary to expectations in an increasingly disordered system, and implying that the valence shift is not related to charge carrier doping. The combined results demonstrate the excellent complementarity between positive physical pressure and negative chemical pressure, and point to a rich playground for exploring the physics and chemistry of strongly correlated electron systems in the general family of Zn20 compounds, despite their structural complexity. PMID:27419654

  6. Electronic structures of interfacial states formed at polymeric semiconductor heterojunctions

    NASA Astrophysics Data System (ADS)

    Huang, Ya-Shih; Westenhoff, Sebastian; Avilov, Igor; Sreearunothai, Paiboon; Hodgkiss, Justin M.; Deleener, Caroline; Friend, Richard H.; Beljonne, David

    2008-06-01

    Heterojunctions between organic semiconductors are central to the operation of light-emitting and photovoltaic diodes, providing respectively for electron-hole capture and separation. However, relatively little is known about the character of electronic excitations stable at the heterojunction. We have developed molecular models to study such interfacial excited electronic excitations that form at the heterojunction between model polymer donor and polymer acceptor systems: poly(9,9-dioctylfluorene-co-bis-N,N-(4-butylphenyl)-bis-N,N-phenyl-1,4-phenylenediamine) (PFB) with poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT), and poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine) (TFB) with F8BT. We find that for stable ground-state geometries the excited state has a strong charge-transfer character. Furthermore, when partly covalent, modelled radiative lifetimes (~10-7s) and off-chain axis polarization (30∘) match observed `exciplex' emission. Additionally for the PFB:F8BT blend, geometries with fully ionic character are also found, thus accounting for the low electroluminescence efficiency of this system.

  7. Quenching of photoexcited states of the proteins chromophores and introduced into the protein macromolecules fluorescent probes by heavy metal ions

    NASA Astrophysics Data System (ADS)

    Melnikov, A. G.; Dyachuk, O. A.; Melnikov, G. V.

    2015-03-01

    We have studied the processes of quenching of photoexcited states of fluorescent probes and quenching of the fluorescence of the chromophores of human serum albumin (HSA) by heavy metal ions (HM): cations Tl+, Pb2+, Cu2+, Cd2+, and the anion of iodine (I-). We used the dye from xanthene series - eosin as a fluorescent probe. By quenching of the fluorescence of protein chromophores we found an influence of HM on the structure of proteins, resulting in a shift of the peak of the fluorescence of HSA tryptophanyl. This can be explained by proteins denaturation under the influence of heavy metals and penetration of water into the inner environment of HSA tryptophan. It was established that the constant of the quenching of the probe phosphorescence is much higher than the fluorescence, which is explained by significantly longer lifetime of the photoexcited states of fluorescent probes in the triplet state than in the singlet.

  8. SPiRIT-TPC with GET readout electronics for the study of density dependent symmetry energy of high dense matter with Heavy RI collisions

    NASA Astrophysics Data System (ADS)

    Isobe, Tadaaki; SPiRIT Collaboration

    2014-09-01

    The nuclear Equation of State (EoS) is a fundamental property of nuclear matter that describes the relationships between the parameters for a nuclear system, such as energy, density and temperature. An international collaboration, named SPiRIT, to study the nuclear EoS has been formed recently. One of the main devices of experimental setup is a Time Projection Chamber (TPC) which will be installed into the SAMURAI dipole magnet at RIKEN-RIBF. The TPC can measure charged pions, protons and light ions simultaneously in heavy RI collisions, and those will be used as probes to study the asymmetric dense nuclear matter. In addition to the status of the SPiRIT project, testing of SPiRIT-TPC with GET electronics will be presented in this talk. GET, general electronics for TPC, is a project for the development of novel electronics for TPC supported by NSF and ANR. This work is supported in part by the Japan Grant-in-Aide award and the US DOE grant DE-SC0004835 and JUSEIPEN.

  9. Supercoupling between heavy-hole and light-hole states in nanostructures

    NASA Astrophysics Data System (ADS)

    Luo, Jun-Wei; Bester, Gabriel; Zunger, Alex

    2015-10-01

    The heavy-hole (HH) and light-hole (LH) components of the valence states in three-dimensional (3D) bulk semiconductors can mix quantum mechanically as the dimensionality is reduced in forming low-D nanostructures, such as 2D quantum wells, 1D quantum wires, and 0D quantum dots (QDs). This coupling controls the tuning of the excitonic fine-structure splitting, provides an efficient channel for the spin coherence, and leads to polarization anisotropy of light emission, central to several quantum-information schemes. The current understanding is that the mixing scales with the square of δ VHL/ΔHL , where δ VHL and ΔHL are the coupling matrix elements of the crystal potential and the energy separation between the primary HH0 and LH0 states, respectively. We discuss two classes of HH-LH coupling mechanisms. First, coupling factors occurring through the numerator δ VHL , referred to as "direct coupling," including the well-known (i) quantum confinement, (ii) built-in strain, and (iii) shape elongation, as well as three additional direct coupling mechanisms discussed here: (iv) the intrinsic C2 v crystal-field effect, (v) the local symmetry of the interface, and (vi) the alloy disorder. We quantify these six direct HH-LH coupling effects by performing atomistic pseudopotential calculations on a range of strained and unstrained QDs of different morphologies. We find that in unstrained self-assembled QDs such as GaAs/AlGaAs, effects (i)-(vi) contribute 0%, 0%, 0%, 0%, 40%, and 60%, respectively, whereas in strained self-assembled QDs such as InGaAs/GaAs they contribute 0%, 0%, 78%, 0%, 8%, and 14%, respectively, to the direct HH-LH coupling δ VHL . These relative contributions to direct HH-LH coupling differ significantly from what was previously believed. Second, we discover an unexpected HH-LH supercoupling that effectively reduces the denominator ΔHL by the presence of a dense ladder of intermediate states between the HH0 and LH0 states (analogous to superexchange

  10. Progress towards Generating Rydberg State, One Electron Ions

    NASA Astrophysics Data System (ADS)

    Dreiling, Joan; Fogwell Hoogerheide, Shannon; Naing, Aung; Tan, Joseph

    2016-05-01

    We report on progress towards producing hydrogen-like ions in Rydberg states from bare nuclei. Fully stripped neon atoms (Ne10+) are produced by the electron beam ion trap (EBIT) at NIST. These ions are extracted via a beamline from the EBIT into a second apparatus where they are captured at low energy in a unitary Penning trap. The second apparatus has a cross-beam configuration, with a perpendicular beam of laser excited Rb atoms intersecting the ion beam at the Penning trap. While stored in the trap, the ions can interact with the Rb and, through charge exchange interactions, the bare nuclei can capture one or more electrons from the Rb. The ions are then analyzed by dumping the trap to a time-of-flight detector, which allows determination of the ion charge state evolution. This work builds towards laser spectroscopy on hydrogen-like ions in circular Rydberg states to obtain a value for the Rydberg constant independent of nuclear size effects. Such a measurement could shed some light on the proton radius puzzle.

  11. Field-orientation dependence of low-energy quasiparticle excitations in the heavy-electron superconductor UBe(13).

    PubMed

    Shimizu, Yusei; Kittaka, Shunichiro; Sakakibara, Toshiro; Haga, Yoshinori; Yamamoto, Etsuji; Amitsuka, Hiroshi; Tsutsumi, Yasumasa; Machida, Kazushige

    2015-04-10

    Low-energy quasiparticle excitations in the superconducting (SC) state of UBe_{13} were studied by means of specific-heat (C) measurements in a rotating field. Quite unexpectedly, the magnetic-field dependence of C(H) is linear in H with no angular dependence at low fields in the SC state, implying that the gap is fully open over the Fermi surfaces, in stark contrast to previous expectations. In addition, a characteristic cubic anisotropy of C(H) was observed above 2 T with a maximum (minimum) for H∥[001] ([111]) within the (11[over ¯]0) plane, in the normal as well as in the SC states. This oscillation possibly originates from the anisotropic response of the heavy quasiparticle bands, and might be a key to understand the unusual properties of UBe_{13}. PMID:25910153

  12. State-resolved three-dimensional electron-momentum correlation in nonsequential double ionization of benzene

    NASA Astrophysics Data System (ADS)

    Winney, Alexander H.; Lin, Yun Fei; Lee, Suk Kyoung; Adhikari, Pradip; Li, Wen

    2016-03-01

    We report state-resolved electron-momentum correlation measurement of strong-field nonsequential double ionization in benzene. With a novel coincidence detection apparatus, highly efficient triple coincidence (electron-electron dication) and quadruple coincidence (electron-electron-cation-cation) are used to resolve the final ionic states and to characterize three-dimensional (3D) electron-momentum correlation. The primary states associated with dissociative and nondissociative dications are assigned. A 3D momentum anticorrelation is observed for the electrons in coincidence with dissociative benzene dication states whereas such a correlation is absent for nondissociative dication states.

  13. Invisible Electronic States and Their Dynamics Revealed by Perturbations

    NASA Astrophysics Data System (ADS)

    Merer, Anthony J.

    2011-06-01

    Sooner or later everyone working in the field of spectroscopy encounters perturbations. These can range in size from a small shift of a single rotational level to total destruction of the vibrational and rotational patterns of an electronic state. To some workers perturbations are a source of terror, but to others they are the most fascinating features of molecular spectra, because they give information about molecular dynamics, and about states that would otherwise be invisible as a result of unfavorable selection rules. An example of the latter is the essentially complete characterization of the tilde{b}^3A_2 state of SO_2 from the vibronic perturbations it causes in the tilde{a}^3B_1 state. The S_1-trans state of acetylene is a beautiful example of dynamics in action. The level patterns of the three bending vibrations change dramatically with increasing vibrational excitation as a result of the vibrational angular momentum and the approach to the isomerization barrier. Several vibrational levels of the S_1-cis isomer, previously thought to be unobservable, can now be assigned. They obtain their intensity through interactions with nearby levels of the trans isomer.

  14. Differential cross sections for electron-impact excitation of the electronic states of N sub 2

    SciTech Connect

    Brunger, M.J.; Teubner, P.J.O. )

    1990-02-01

    Differential cross sections for the electron-impact excitation of the first ten electronic states of N{sub 2} have been determined at five incident energies ranging from 15 to 50 eV. These differential cross sections were obtained for the scattering range 10{degree}--90{degree} by analyzing electron-energy-loss spectra in N{sub 2} at a number of fixed scattering angles within that range. The present study represents a comprehensive remeasurement of the earlier work of Cartwright and co-workers (Phys. Rev. A 16, 1013 (1977)) and was undertaken with a view to resolving certain anomalies which have been reported in the literature when the earlier cross-section set has been applied to model calculations of swarm parameters.

  15. Determination of mass attenuation coefficients, effective atomic numbers and effective electron numbers for heavy-weight and normal-weight concretes.

    PubMed

    Un, Adem; Demir, Faruk

    2013-10-01

    Total mass attenuation coefficients, effective atomic numbers and effective electron numbers values for different 16 heavy-weight and normal-weight concretes are calculated in the energy range from 1 keV to 100 GeV. The values of mass attenuation coefficients used in calculations are taken from the WinXCom computer program. The obtained results for heavy-weight concretes are compared with the results for normal-weight concretes. The results of heavy-weight concretes fairly differ from results for normal-weight concretes. PMID:23838359

  16. MRCI study on electronic spectrum of 13 electronic states of SiP molecule

    NASA Astrophysics Data System (ADS)

    Shi, Deheng; Xing, Wei; Liu, Hui; Sun, Jinfeng; Zhu, Zunlue

    2012-11-01

    The potential energy curves (PECs) of the X2Π, A2Σ+, a4Σ+, B2Π, c4Δ, C2Σ+, d4Σ-, D2Φ, E2Σ-, G2Δ, H2Π, I2Σ+ and f4Δ electronic states of the SiP molecule are calculated employing an ab initio quantum chemical method. The PEC calculations are performed for internuclear separations from 0.10 to 1.10 nm using the complete active space self-consistent field (CASSCF) method, which is followed by the internally contracted multireference configuration interaction (MRCI) approach in combination with a correlation-consistent aug-cc-pV6Z basis set. To improve the quality of the PECs, core-valence correlation and scalar relativistic corrections are included. Scalar relativistic correction calculations are carried out using the third-order Douglas-Kroll Hamiltonian approximation at the level of a cc-pV5Z basis set. Core-valence correlation corrections are included using a cc-pCVQZ basis set. The PECs obtained by the MRCI calculations are corrected for size-extensivity errors by means of the Davidson modification. The PECs are extrapolated to the complete basis set limit. The spectroscopic parameters are obtained by fitting the vibrational levels, which are calculated by solving the ro-vibrational Schrödinger equation. The spectroscopic results are compared in detail with those reported in previous literature. Excellent agreement is found between the present spectroscopic results and the experimental ones. Using the Breit-Pauli operator, the spin-orbit (SO) coupling effect on the spectroscopic parameters is included in the X2Π, D2Φ and H2Π electronic states at the level of a cc-pCVTZ basis set. The energy separation of the X2Π and A2Σ+ electronic states is accurately determined by including the Davidson modification, SO coupling and core-valence correlation and scalar relativistic corrections. Using the PECs determined by the MRCI + Q/CV + DK + 56 calculations, the G(υ), Bυ and Dυ are calculated for each vibrational state of each electronic state, and those

  17. MRCI study on electronic spectrum of 13 electronic states of SiP molecule.

    PubMed

    Shi, Deheng; Xing, Wei; Liu, Hui; Sun, Jinfeng; Zhu, Zunlue

    2012-11-01

    The potential energy curves (PECs) of the X(2)Π, A(2)Σ(+), a(4)Σ(+), B(2)Π, c(4)Δ, C(2)Σ(+), d(4)Σ(-), D(2)Φ, E(2)Σ(-), G(2)Δ, H(2)Π, I(2)Σ(+) and f(4)Δ electronic states of the SiP molecule are calculated employing an ab initio quantum chemical method. The PEC calculations are performed for internuclear separations from 0.10 to 1.10nm using the complete active space self-consistent field (CASSCF) method, which is followed by the internally contracted multireference configuration interaction (MRCI) approach in combination with a correlation-consistent aug-cc-pV6Z basis set. To improve the quality of the PECs, core-valence correlation and scalar relativistic corrections are included. Scalar relativistic correction calculations are carried out using the third-order Douglas-Kroll Hamiltonian approximation at the level of a cc-pV5Z basis set. Core-valence correlation corrections are included using a cc-pCVQZ basis set. The PECs obtained by the MRCI calculations are corrected for size-extensivity errors by means of the Davidson modification. The PECs are extrapolated to the complete basis set limit. The spectroscopic parameters are obtained by fitting the vibrational levels, which are calculated by solving the ro-vibrational Schrödinger equation. The spectroscopic results are compared in detail with those reported in previous literature. Excellent agreement is found between the present spectroscopic results and the experimental ones. Using the Breit-Pauli operator, the spin-orbit (SO) coupling effect on the spectroscopic parameters is included in the X(2)Π, D(2)Φ and H(2)Π electronic states at the level of a cc-pCVTZ basis set. The energy separation of the X(2)Π and A(2)Σ(+) electronic states is accurately determined by including the Davidson modification, SO coupling and core-valence correlation and scalar relativistic corrections. Using the PECs determined by the MRCI+Q/CV+DK+56 calculations, the G(υ), B(υ) and D(υ) are calculated for each

  18. Topology and quantum states: The electron-monopole system

    NASA Astrophysics Data System (ADS)

    Di Cosmo, F.; Marmo, G.; Zampini, A.

    2016-09-01

    This paper starts by describing the dynamics of the electron-monopole system at both classical and quantum level by a suitable reduction procedure. This suggests, in order to realise the space of states for quantum systems which are classically described on topologically non-trivial configuration spaces, to consider Hilbert spaces of exterior differential forms. Among the advantages of this formulation, we present--in the case of the group SU(2) , how it is possible to obtain all unitary irreducible representations on such a Hilbert space, and how it is possible to write scalar Dirac-type operators, following an idea by Kähler.

  19. Cage electron-hydroxyl complex state as electron donor in mayenite

    NASA Astrophysics Data System (ADS)

    Hiraishi, M.; Kojima, K. M.; Miyazaki, M.; Yamauchi, I.; Okabe, H.; Koda, A.; Kadono, R.; Matsuishi, S.; Hosono, H.

    2016-03-01

    It is inferred from the chemical shift of muon spin rotation (μ SR ) spectra that muons implanted in pristine (fully oxidized) mayenite, [Ca12Al14O32] 2 +[□5O2 -] (C12A7, with □ referring to the vacant cage), are bound to O2 - at the cage center to form OMu- (where Mu represents muonium, a muonic analog of the H atom). However, an isolated negatively charged state (Mu-, an analog of H-) becomes dominant when the compound approaches the state of electride [Ca12Al14O32] 2 +[□42 e-] as a result of the reduction process. Moreover, the OMu- state in the pristine specimen exhibits depolarization of paramagnetic origin at low temperatures (below ˜30 K), indicating that OMu- accompanies a loosely bound electron in the cage that can be thermally activated. This suggests that interstitial muons (and hence H) forming a "cage electron-hydroxyl" complex can serve as electron donors in C12A7.

  20. Semiclassical Dynamics of Electron Wave Packet States with Phase Vortices

    SciTech Connect

    Bliokh, Konstantin Yu.; Bliokh, Yury P.; Savel'ev, Sergey; Nori, Franco

    2007-11-09

    We consider semiclassical higher-order wave packet solutions of the Schroedinger equation with phase vortices. The vortex line is aligned with the propagation direction, and the wave packet carries a well-defined orbital angular momentum (OAM) ({Dirac_h}/2{pi})l (l is the vortex strength) along its main linear momentum. The probability current coils around the momentum in such OAM states of electrons. In an electric field, these states evolve like massless particles with spin l. The magnetic-monopole Berry curvature appears in momentum space, which results in a spin-orbit-type interaction and a Berry/Magnus transverse force acting on the wave packet. This brings about the OAM Hall effect. In a magnetic field, there is a Zeeman interaction, which, can lead to more complicated dynamics.

  1. Recent progress of probing correlated electron states by point contact spectroscopy.

    PubMed

    Lee, Wei-Cheng; Greene, Laura H

    2016-09-01

    across the junction leads to the conclusion that the point contact conductance is proportional to the effective density of states, a physical quantity that can be computed if the electron self energy is known. The experimental data on iron based superconductors and heavy fermion compounds will be analyzed in this framework. These recent developments have extended the applicability of point contact spectroscopy to correlated materials, which will help us achieve a deeper understanding of the single electron dynamics in strongly correlated systems. PMID:27533341

  2. Recent progress of probing correlated electron states by point contact spectroscopy

    NASA Astrophysics Data System (ADS)

    Lee, Wei-Cheng; Greene, Laura H.

    2016-09-01

    distributed across the junction leads to the conclusion that the point contact conductance is proportional to the effective density of states, a physical quantity that can be computed if the electron self energy is known. The experimental data on iron based superconductors and heavy fermion compounds will be analyzed in this framework. These recent developments have extended the applicability of point contact spectroscopy to correlated materials, which will help us achieve a deeper understanding of the single electron dynamics in strongly correlated systems.

  3. Modeling the high-energy electronic state manifold of adenine: Calibration for nonlinear electronic spectroscopy

    SciTech Connect

    Nenov, Artur Giussani, Angelo; Segarra-Martí, Javier; Jaiswal, Vishal K.; Rivalta, Ivan; Cerullo, Giulio; Mukamel, Shaul; Garavelli, Marco E-mail: marco.garavelli@ens-lyon.fr

    2015-06-07

    Pump-probe electronic spectroscopy using femtosecond laser pulses has evolved into a standard tool for tracking ultrafast excited state dynamics. Its two-dimensional (2D) counterpart is becoming an increasingly available and promising technique for resolving many of the limitations of pump-probe caused by spectral congestion. The ability to simulate pump-probe and 2D spectra from ab initio computations would allow one to link mechanistic observables like molecular motions and the making/breaking of chemical bonds to experimental observables like excited state lifetimes and quantum yields. From a theoretical standpoint, the characterization of the electronic transitions in the visible (Vis)/ultraviolet (UV), which are excited via the interaction of a molecular system with the incoming pump/probe pulses, translates into the determination of a computationally challenging number of excited states (going over 100) even for small/medium sized systems. A protocol is therefore required to evaluate the fluctuations of spectral properties like transition energies and dipole moments as a function of the computational parameters and to estimate the effect of these fluctuations on the transient spectral appearance. In the present contribution such a protocol is presented within the framework of complete and restricted active space self-consistent field theory and its second-order perturbation theory extensions. The electronic excited states of adenine have been carefully characterized through a previously presented computational recipe [Nenov et al., Comput. Theor. Chem. 1040–1041, 295-303 (2014)]. A wise reduction of the level of theory has then been performed in order to obtain a computationally less demanding approach that is still able to reproduce the characteristic features of the reference data. Foreseeing the potentiality of 2D electronic spectroscopy to track polynucleotide ground and excited state dynamics, and in particular its expected ability to provide

  4. Modeling the high-energy electronic state manifold of adenine: Calibration for nonlinear electronic spectroscopy.

    PubMed

    Nenov, Artur; Giussani, Angelo; Segarra-Martí, Javier; Jaiswal, Vishal K; Rivalta, Ivan; Cerullo, Giulio; Mukamel, Shaul; Garavelli, Marco

    2015-06-01

    Pump-probe electronic spectroscopy using femtosecond laser pulses has evolved into a standard tool for tracking ultrafast excited state dynamics. Its two-dimensional (2D) counterpart is becoming an increasingly available and promising technique for resolving many of the limitations of pump-probe caused by spectral congestion. The ability to simulate pump-probe and 2D spectra from ab initio computations would allow one to link mechanistic observables like molecular motions and the making/breaking of chemical bonds to experimental observables like excited state lifetimes and quantum yields. From a theoretical standpoint, the characterization of the electronic transitions in the visible (Vis)/ultraviolet (UV), which are excited via the interaction of a molecular system with the incoming pump/probe pulses, translates into the determination of a computationally challenging number of excited states (going over 100) even for small/medium sized systems. A protocol is therefore required to evaluate the fluctuations of spectral properties like transition energies and dipole moments as a function of the computational parameters and to estimate the effect of these fluctuations on the transient spectral appearance. In the present contribution such a protocol is presented within the framework of complete and restricted active space self-consistent field theory and its second-order perturbation theory extensions. The electronic excited states of adenine have been carefully characterized through a previously presented computational recipe [Nenov et al., Comput. Theor. Chem. 1040-1041, 295-303 (2014)]. A wise reduction of the level of theory has then been performed in order to obtain a computationally less demanding approach that is still able to reproduce the characteristic features of the reference data. Foreseeing the potentiality of 2D electronic spectroscopy to track polynucleotide ground and excited state dynamics, and in particular its expected ability to provide

  5. Modeling the high-energy electronic state manifold of adenine: Calibration for nonlinear electronic spectroscopy

    NASA Astrophysics Data System (ADS)

    Nenov, Artur; Giussani, Angelo; Segarra-Martí, Javier; Jaiswal, Vishal K.; Rivalta, Ivan; Cerullo, Giulio; Mukamel, Shaul; Garavelli, Marco

    2015-06-01

    Pump-probe electronic spectroscopy using femtosecond laser pulses has evolved into a standard tool for tracking ultrafast excited state dynamics. Its two-dimensional (2D) counterpart is becoming an increasingly available and promising technique for resolving many of the limitations of pump-probe caused by spectral congestion. The ability to simulate pump-probe and 2D spectra from ab initio computations would allow one to link mechanistic observables like molecular motions and the making/breaking of chemical bonds to experimental observables like excited state lifetimes and quantum yields. From a theoretical standpoint, the characterization of the electronic transitions in the visible (Vis)/ultraviolet (UV), which are excited via the interaction of a molecular system with the incoming pump/probe pulses, translates into the determination of a computationally challenging number of excited states (going over 100) even for small/medium sized systems. A protocol is therefore required to evaluate the fluctuations of spectral properties like transition energies and dipole moments as a function of the computational parameters and to estimate the effect of these fluctuations on the transient spectral appearance. In the present contribution such a protocol is presented within the framework of complete and restricted active space self-consistent field theory and its second-order perturbation theory extensions. The electronic excited states of adenine have been carefully characterized through a previously presented computational recipe [Nenov et al., Comput. Theor. Chem. 1040-1041, 295-303 (2014)]. A wise reduction of the level of theory has then been performed in order to obtain a computationally less demanding approach that is still able to reproduce the characteristic features of the reference data. Foreseeing the potentiality of 2D electronic spectroscopy to track polynucleotide ground and excited state dynamics, and in particular its expected ability to provide

  6. Electron Microscopy: an Analytical Tool for Solid State Physicists

    NASA Astrophysics Data System (ADS)

    van Tendeloo, Gustaaf

    2013-03-01

    For too long the electron microscope has been considered as ``a big magnifying glass.'' Modern electron microscopy however has evolved into an analytical technique, able to provide quantitative data on structure, composition, chemical bonding and magnetic properties. Using lens corrected instruments it is now possible to determine atom shifts at interfaces with a precision of a few picometer; chemical diffusion at these interfaces can be imaged down to atomic scale. The chemical nature of the surface atoms can be visualized and even the bonding state of the elements (e.g. Mn2+ versus Mn3+) can be detected on an atomic scale. Electron microscopy is by principle a projection technique, but the final dream is to obtain atomic info of materials in three dimensions. We will show that this is no longer a dream, but that it is possible using advanced microscopy. We will show evidence of determining the valence change Ce4+ versus Ce3+ at the surface of a CeO2 nanocrystal; the atomic shifts at the interface between LaAlO3 and SrTiO3 and the 3D relaxation of a Au nanocrystal.

  7. Precursor anion states in dissociative electron attachment to chlorophenol isomers

    NASA Astrophysics Data System (ADS)

    Kossoski, F.; Varella, M. T. do N.

    2016-07-01

    We report a theoretical study on low-energy (<10 eV) elastic electron scattering from chlorophenol isomers, namely, para-chlorophenol (pCP), meta-chlorophenol (mCP), and ortho-chlorophenol (oCP). The calculations were performed with the Schwinger multichannel method with pseudopotentials, and analysis of the computed integral cross sections and virtual orbitals revealed one σCCl ∗ , one σOH ∗ , and three π∗ shape resonances. We show that electron capture into the two lower lying π∗ orbitals initiates dissociative processes that lead to the elimination of the chloride ion, accounting for the two overlapping peaks where this fragment was observed. Despite the relatively small differences on the energetics of the π∗ resonances, a major isomeric effect was found on their corresponding autodetachment lifetimes, which accounts for the observed increasing cross sections in the progression pCP < mCP < oCP. In particular, dissociation from the π1 ∗ anion of pCP is largely suppressed because of the unfavorable mixing with the σCCl ∗ state. We found the intramolecular hydrogen bond present in oCP to have the opposite effects of stabilizing the σCCl ∗ resonance and destabilizing the σOH ∗ resonance. We also suggest that the hydrogen abstraction observed in chlorophenols and phenol actually takes place by a mechanism in which the incoming electron is directly attached to the dissociative σOH ∗ orbital.

  8. Simulating Electron Effects in Heavy-Ion Accelerators with Solenoid Focusing

    SciTech Connect

    Sharp, W M; Grote, D P; Cohen, R H; Friedman, A; Molvik, A W; Vay, J; Seidl, P; Roy, P K; Coleman, J E; Haber, I

    2007-06-29

    Contamination from electrons is a concern for solenoid-focused ion accelerators being developed for experiments in high-energy-density physics. These electrons, produced directly by beam ions hitting lattice elements or indirectly by ionization of desorbed neutral gas, can potentially alter the beam dynamics, leading to a time-varying focal spot, increased emittance, halo, and possibly electron-ion instabilities. The electrostatic particle-in-cell code WARP is used to simulate electron-cloud studies on the solenoid-transport experiment (STX) at Lawrence Berkeley National Laboratory. We present self-consistent simulations of several STX configurations and compare the results with experimental data in order to calibrate physics parameters in the model.

  9. Simulating Electron Effects in Heavy-Ion Accelerators with Solenoid Focusing

    SciTech Connect

    Sharp, W. M.; Grote, D. P.; Cohen, R. H.; Friedman, A.; Molvik, A. W.; Vay, J.-L.; Seidl, P. A.; Roy, P. K.; Coleman, J. E.; Haber, I.

    2007-06-20

    Contamination from electrons is a concern for solenoid-focused ion accelerators being developed for experiments in high-energy-density physics. These electrons, produced directly by beam ions hitting lattice elements or indirectly by ionization of desorbed neutral gas, can potentially alter the beam dynamics, leading to a time-varying focal spot, increased emittance, halo, and possibly electron-ion instabilities. The electrostatic particle-in-cell code WARP is used to simulate electron-cloud studies on the solenoid-transport experiment (STX) at Lawrence Berkeley National Laboratory. We present self-consistent simulations of several STX configurations and compare the results with experimental data in order to calibrate physics parameters in the model.

  10. Electronic spectrum of 17 electronic states of BN molecule: a theoretical study.

    PubMed

    Shi, Deheng; Xing, Wei; Liu, Hui; Sun, Jinfeng; Zhu, Zunlue; Liu, Yufang

    2012-07-01

    The potential energy curves (PECs) of the X(3)Π, a(1)Σ(+), b(1)Π, A(3)Σ(+), B(3)Σ(-), c(1)Δ, D(3)Π, 1(5)Π, 3(1)Σ(+), 3(3)Π, 2(1)Π, 2(3)Σ(+), 1(3)Δ, 1(5)Σ(+), 4(3)Π, 2(3)Σ(-) and 1(5)Σ(-) electronic states of the BN molecule are calculated using an ab initio quantum chemical method. The PEC calculations have been made for internuclear separations from 0.06 to 1.20 nm using the complete active space self-consistent field (CASSCF) method, which is followed by the valence internally contracted multireference configuration interaction (MRCI) approach in combination with a correlation-consistent aug-cc-pV5Z basis set. To improve the quality of PECs, core-valence correlation and relativistic corrections are included. Relativistic correction calculations are carried out using the third-order Douglas-Kroll Hamiltonian (DKH3) approximation. Core-valence correlation corrections are included using a cc-pCVQZ basis set. Relativistic corrections are calculated at the level of a cc-pVQZ basis set. To obtain more reliable results, the PECs determined by the MRCI calculations are corrected for size-extensivity errors by means of the Davidson modification (MRCI+Q). These PECs are extrapolated to the complete basis set limit by the total-energy extrapolation scheme. The spectroscopic parameters are determined by fitting the vibrational levels, which are calculated in a direct forward manner from the analytic potential by solving the ro-vibrational Schrödinger equation using Numerov's method. The spectroscopic results have been compared in detail with those reported in the literature. Excellent agreement has been found between the present spectroscopic results and the experimental ones. Using the Breit-Pauli operator, the spin-orbit coupling effect on the spectroscopic parameters is included in the X(3)Π and D(3)Π electronic states. The vibrational level, inertial rotation and centrifugal distortion constants are calculated for each vibrational state of each

  11. Electronic stopping power data of heavy ions in polymeric foils in the ion energy domain of LSS theory

    NASA Astrophysics Data System (ADS)

    Dib, A.; Ammi, H.; Hedibel, M.; Guesmia, A.; Mammeri, S.; Msimanga, M.; Pineda-Vargas, C. A.

    2015-11-01

    A continuous energy loss measurements of 63Cu, 28Si, 27Al, 24Mg, 19F, 16O and 12C ions over an energy range of (0.06-0.65) MeV/nucleon through thin polymeric foils (Mylar, Polypropylene and Formvar) were carried out by time of flight spectrometry. The deduced experimental stopping data have been used in order to assess our proposed semi empirical formula. The proposed approach based on the Firsov and Lindhard-Scharff stopping power models is provided for well describing-the electronic stopping power of heavy ions (3 ⩽ Z < 100) in various solids targets at low energy range. The ζe factor, which was approximated to be ∼Z11/6 , involved in Lindhard, Scharff and Schiott (LSS) formula has been suitably modified in the light of the available experimental stopping power data. The calculated stopping power values after incorporating, effective charge Z1∗ of moving heavy ions with low velocities (v ⩽v0Z12/3) and modified ζe in LSS formula, have been found to be in close agreement with measured values in various solids targets. A reason of energy loss measurements is to obtain data that help to assess our understanding of the stopping power theories. For this, the obtained results are compared with, LSS calculations, MSTAR and SRIM-2013 predictions code.

  12. Electronic transport in the quantum spin Hall state due to the presence of adatoms in graphene

    NASA Astrophysics Data System (ADS)

    Lima, Leandro; Lewenkopf, Caio

    Heavy adatoms, even at low concentrations, are predicted to turn a graphene sheet into a topological insulator with substantial gap. The adatoms mediate the spin-orbit coupling that is fundamental to the quantum spin Hall effect. The adatoms act as local spin-orbit scatterer inducing hopping processes between distant carbon atoms giving origin to transverse spin currents. Although there are effective models that describe spectral properties of such systems with great detail, quantitative theoretical work for the transport counterpart is still lacking. We developed a multiprobe recursive Green's function technique with spin resolution to analyze the transport properties for large geometries. We use an effective tight-binding Hamiltonian to describe the problem of adatoms randomly placed at the center of the honeycomb hexagons, which is the case for most transition metals. Our choice of current and voltage probes is favorable to experiments since it filters the contribution of only one spin orientation, leading to a quantized spin Hall conductance of e2 / h . We also discuss the electronic propagation in the system by imaging the local density of states and the electronic current densities. The authors acknowledge the Brazilian agencies CNPq, CAPES, FAPERJ and INCT de Nanoestruturas de Carbono for financial support.

  13. Simultaneous atomic-resolution electron ptychography and Z-contrast imaging of light and heavy elements in complex nanostructures.

    PubMed

    Yang, H; Rutte, R N; Jones, L; Simson, M; Sagawa, R; Ryll, H; Huth, M; Pennycook, T J; Green, M L H; Soltau, H; Kondo, Y; Davis, B G; Nellist, P D

    2016-01-01

    The aberration-corrected scanning transmission electron microscope (STEM) has emerged as a key tool for atomic resolution characterization of materials, allowing the use of imaging modes such as Z-contrast and spectroscopic mapping. The STEM has not been regarded as optimal for the phase-contrast imaging necessary for efficient imaging of light materials. Here, recent developments in fast electron detectors and data processing capability is shown to enable electron ptychography, to extend the capability of the STEM by allowing quantitative phase images to be formed simultaneously with incoherent signals. We demonstrate this capability as a practical tool for imaging complex structures containing light and heavy elements, and use it to solve the structure of a beam-sensitive carbon nanostructure. The contrast of the phase image contrast is maximized through the post-acquisition correction of lens aberrations. The compensation of defocus aberrations is also used for the measurement of three-dimensional sample information through post-acquisition optical sectioning. PMID:27561914

  14. Simultaneous atomic-resolution electron ptychography and Z-contrast imaging of light and heavy elements in complex nanostructures

    PubMed Central

    Yang, H.; Rutte, R. N.; Jones, L.; Simson, M.; Sagawa, R.; Ryll, H.; Huth, M.; Pennycook, T. J.; Green, M.L.H.; Soltau, H.; Kondo, Y.; Davis, B. G.; Nellist, P. D.

    2016-01-01

    The aberration-corrected scanning transmission electron microscope (STEM) has emerged as a key tool for atomic resolution characterization of materials, allowing the use of imaging modes such as Z-contrast and spectroscopic mapping. The STEM has not been regarded as optimal for the phase-contrast imaging necessary for efficient imaging of light materials. Here, recent developments in fast electron detectors and data processing capability is shown to enable electron ptychography, to extend the capability of the STEM by allowing quantitative phase images to be formed simultaneously with incoherent signals. We demonstrate this capability as a practical tool for imaging complex structures containing light and heavy elements, and use it to solve the structure of a beam-sensitive carbon nanostructure. The contrast of the phase image contrast is maximized through the post-acquisition correction of lens aberrations. The compensation of defocus aberrations is also used for the measurement of three-dimensional sample information through post-acquisition optical sectioning. PMID:27561914

  15. Comparison of the degradation effects of heavy ion, electron, and cobalt-60 irradiation in an advanced bipolar process

    NASA Technical Reports Server (NTRS)

    Zoutendyk, John A.; Goben, Charles A.; Berndt, Dale F.

    1988-01-01

    Experimental measurements are reported of the degradation effects of high-energy particles (heavy Br ions and electrons) and Co-60 gamma-rays on the current gain of minimum-geometry bipolar transistors made from an advanced process. The data clearly illustrate the total-ionizing-dose vs particle-fluence behavior of this bipolar transistor produced by an advanced process. In particular, bulk damage from Co-60 gamma rays in bipolar transistors (base transport factor degradation) and surface damage in bipolar transistors from ionizing radiation (emitter-efficiency degradation) have been observed. The true equivalence between various types of radiation for this process technology has been determined on the basis of damage from the log K1 intercepts.

  16. Muon Knight shift in d-electron heavy fermion compound Y0.95Sc0.05Mn2

    NASA Astrophysics Data System (ADS)

    Yamauchi, I.; Miyazaki, M.; Hiraishi, M.; Koda, A.; Kojima, K. M.; Kadono, R.; Nakamura, H.

    2014-12-01

    We report on the muon Knight shift in a polycrystalline sample of Y0.95Sc0.05Mn2 that is known as one of the d-electron heavy fermion compounds. Since the muon site is presumed to have a trigonal symmetry, it is expected that the Fourier-transformed (FT) spectrum line shape would exhibit a uni-axial powder pattern which has two edges determined by the parallel and perpendicular components of the Knight shift, K|| and K⊥, where K|| (K⊥) is proportional to the parallel (perpendicular) component of the spin susceptibility, χ|| (χ⊥). The observed FT spectrum at 2 K largely disagrees with the calculated line shape in isotropic (χ|| = χ⊥) and anisotropic (χ|| ≠ χ⊥) cases, suggesting that there must be field- induced staggered magnetization due to strong antiferromagnetic spin correlations.

  17. Influence of electronic energy deposition on the structural modification of swift heavy-ion-irradiated amorphous germanium layers

    SciTech Connect

    Steinbach, T.; Schnohr, C. S.; Wesch, W.; Kluth, P.; Giulian, R.; Araujo, L. L.; Sprouster, D. J.; Ridgway, M. C.

    2011-02-01

    Swift heavy-ion (SHI) irradiation of amorphous germanium (a-Ge) layers leads to a strong volume expansion accompanied by a nonsaturating irreversible plastic deformation (ion hammering), which are consequences of the high local electronic energy deposition within the region of the a-Ge layer. We present a detailed study of the influence of SHI irradiation parameters on the effect of plastic deformation and structural modification. Specially prepared a-Ge layers were irradiated using two SHI energies and different angles of incidence, thus resulting in a variation of the electronic energy deposition per depth {epsilon}{sub e} between 14.0 and 38.6 keV nm{sup -1}. For all irradiation parameters used a strong swelling of the irradiated material was observed, which is caused by the formation and growth of randomly distributed voids, leading to a gradual transformation of the amorphous layer into a sponge-like porous structure as established by cross-section scanning electron microscopy investigations. The swelling depends linearly on the ion fluence and on the value of {epsilon}{sub e}, thus clearly demonstrating that the structural changes are determined solely by the electronic energy deposited within the amorphous layer. Plastic deformation shows a superlinear dependence on the ion fluence due to the simultaneous volume expansion. This influence of structural modification on plastic deformation is described by a simple approach, thus allowing estimation of the deformation yield. With these results the threshold values of the electronic energy deposition for the onset of both structural modification and plastic deformation due to SHI irradiation are determined. Furthermore, based on these results, the longstanding question concerning the reason for the structural modification observed in SHI-irradiated crystalline Ge is answered.

  18. 75 FR 69660 - Cross-Media Electronic Reporting Rule State Authorized Program Revision Approval: State of Hawaii

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-15

    ... the Federal Register (70 FR 59848) and codified as part 3 of title 40 of the CFR. CROMERR establishes... AGENCY Cross-Media Electronic Reporting Rule State Authorized Program Revision Approval: State of Hawaii... approval, under regulations for Cross-Media Electronic Reporting, of the State of Hawaii's request...

  19. 75 FR 65627 - Cross-Media Electronic Reporting Rule State Authorized Program Revision Approval: State of Arkansas

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-26

    ... the Federal Register (70 FR 59848) and codified as part 3 of title 40 of the CFR. CROMERR establishes... AGENCY Cross-Media Electronic Reporting Rule State Authorized Program Revision Approval: State of...'s approval, under regulations for Cross-Media Electronic Reporting, of the State of...

  20. Electron Cloud Measurements in Heavy-Ion Driver for HEDP and Inertial Fusion Energy

    SciTech Connect

    Covo, M K; Molvik, A W; Friedman, A; Cohen, R; Vay, J; Bieniosek, F; Baca, D; Seidl, P A; Logan, G; Vujic, J L

    2006-08-16

    The High Current Experiment (HCX) at LBNL is a driver scale single beam injector that provides a 1 MeV K+ ion beam current of 0.18 A for 5 {micro}s. It transports high-current beams with large fill factor (ratio of the maximum beam envelope radius to the beam pipe radius) and low emittance growth that are required to keep the cost of the power plant competitive and to satisfy the target requirements of focusing ion beams to high-power density. Beam interaction with the background gas and walls desorbs electrons that can multiply and accumulate, creating an electron cloud. This ubiquitous effect grows at higher fill factors and degrades the quality of the beam. We review simulations and diagnostics tools used to measure electron production, accumulation and its properties.

  1. Relativistic theory for radiative forward electron emission in heavy ion-atom encounters

    NASA Astrophysics Data System (ADS)

    Jakubaßa-Amundsen, Doris; Müller, Robert; Surzhykov, Andrey; Yerokhin, Vladimir

    2014-12-01

    The forward electron emission with simultaneous photon production during the scattering of relativistic, highly stripped projectiles from light target atoms is calculated within the Dirac theory. The method of calculation is a simplification of the impulse approximation and is based on the relation of the cross section for radiative capture to continuum of loosely bound electrons to the frame-transformed electron bremsstrahlung cross section. It is demonstrated that such an approximation is well justified in a large region of energies and photon emission angles, with the exception of the extreme forward and backward emission and the soft-photon energy limit. The cusp spectrum and the corresponding angular distribution are compared to recent experimental data for the collision system 90.38 MeV/amu U88+ + N2.

  2. Electronic structure of the unoccupied electron energy states in FeSe1-xTex

    NASA Astrophysics Data System (ADS)

    Mishra, Pramita; Lohani, Himanshu; Maniraj, M.; Nayak, Jayita; Zargar, R. A.; Awana, V. P. S.; Barman, Sudipta Roy; Sekhar, Biju Raja

    2015-10-01

    Inverse photoemission spectroscopic (IPES) measurements along with LDA based band structure calculations have been used to investigate the unoccupied electronic structure of FeSe1-xTex system. The observed doping and temperature dependent pseudogap in this system is found to be linked to the change in the chalcogen height in their geometric structure. The depletion in spectral weight from the near EF states at low temperature in IPES has been correlated with the enhancement of the 3z2-r2 orbitals in the photoemission spectroscopy (PES). The Coulomb correlation energy U, estimated from the combined PES and IPES spectra, signifies the enhancement in electron correlations in FeSe1-xTex, with doping. The formation of pseudogap in PES and IPES confirms the importance of correlations in the 11 family of Fe superconductors.

  3. Negative-continuum dielectronic recombination for heavy ions

    SciTech Connect

    Artemyev, A.N.; Yerokhin, V.A.; Beier, T.; Kozhuharov, C.; Eichler, J.; Klasnikov, A.E.; Shabaev, V.M.; Stoehlker, T.

    2003-05-01

    The process of recombination of an electron with a bare heavy nucleus via the creation of a free-positron-bound-electron pair is considered. This process is denoted as 'negative-continuum dielectronic recombination' because it results in the capture of an incident electron into a bound state accompanied by a transition of a negative-continuum electron into a bound state. The calculations are performed for a wide range of incident electron energies for Z=82 and 92.

  4. Spectroscopic investigations of L-shell ionization in heavy elements by electron impact

    NASA Astrophysics Data System (ADS)

    Rahangdale, H. V.; Mitra, D.; Das, P. K.; De, S.; Guerra, M.; Santos, J. P.; Saha, S.

    2016-05-01

    The absolute L subshell specific electron impact ionization cross sections near the ionization threshold (16 < E < 45 keV) of lead and thorium are obtained from the measured L X-ray production cross sections. Monte Carlo simulation is done to account for the effect of the backscattered electrons, and the final experimental results are compared with calculations performed using distorted wave Born approximation and the modified relativistic binary encounter Bethe model. The sensitivity of the results on the atomic parameters is explored. Observed agreements and discrepancies between the experimental results and theoretical estimates, and their dependence on the specific atomic parameters are reported.

  5. Electron excitation from ground state to first excited state: Bohmian mechanics method

    NASA Astrophysics Data System (ADS)

    Yang, Song; Shuang, Zhao; Fu-Ming, Guo; Yu-Jun, Yang; Su-Yu, Li

    2016-03-01

    The excitation process of electrons from the ground state to the first excited state via the resonant laser pulse is investigated by the Bohmian mechanics method. It is found that the Bohmian particles far away from the nucleus are easier to be excited and are excited firstly, while the Bohmian particles in the ground state is subject to a strong quantum force at a certain moment, being excited to the first excited state instantaneously. A detailed analysis for one of the trajectories is made, and finally we present the space and energy distribution of 2000 Bohmian particles at several typical instants and analyze their dynamical process at these moments. Project supported by the Doctoral Research Start-up Funding of Northeast Dianli University, China (Grant No. BSJXM-201332), the National Natural Science Foundation of China (Grant Nos. 11547114, 11534004, 11474129, 11274141, 11447192, and 11304116), and the Graduate Innovation Fund of Jilin University, China (Grant No. 2015091).

  6. Two dimensional electron systems for solid state quantum computation

    NASA Astrophysics Data System (ADS)

    Mondal, Sumit

    Two dimensional electron systems based on GaAs/AlGaAs heterostructures are extremely useful in various scientific investigations of recent times including the search for quantum computational schemes. Although significant strides have been made over the past few years to realize solid state qubits on GaAs/AlGaAs 2DEGs, there are numerous factors limiting the progress. We attempt to identify factors that have material and design-specific origin and develop ways to overcome them. The thesis is divided in two broad segments. In the first segment we describe the realization of a new field-effect induced two dimensional electron system on GaAs/AlGaAs heterostructure where the novel device-design is expected to suppress the level of charge noise present in the device. Modulation-doped GaAs/AlGaAs heterostructures are utilized extensively in the study of quantum transport in nanostructures, but charge fluctuations associated with remote ionized dopants often produce deleterious effects. Electric field-induced carrier systems offer an attractive alternative if certain challenges can be overcome. We demonstrate a field-effect transistor in which the active channel is locally devoid of modulation-doping, but silicon dopant atoms are retained in the ohmic contact region to facilitate low-resistance contacts. A high quality two-dimensional electron gas is induced by a field-effect that is tunable over a density range of 6.5x10 10cm-2 to 2.6x1011cm-2 . Device design, fabrication, and low temperature (T=0.3K) characterization results are discussed. The demonstrated device-design overcomes several existing limitations in the fabrication of field-induced 2DEGs and might find utility in hosting nanostructures required for making spin qubits. The second broad segment describes our effort to correlate transport parameters measured at T=0.3K to the strength of the fractional quantum Hall state observed at nu=5/2 in the second Landau level of high-mobility GaAs/AlGaAs two dimensional

  7. Electronic states and spectra of BiH

    NASA Astrophysics Data System (ADS)

    Setzer, Klaus-Dieter; Fink, Ewald H.; Hill, Christian; Brown, John M.

    2015-06-01

    Emission spectra of bismuth monohydride (BiH) radicals excited by energy transfer from O2(a1Δg) or NF(a1Δ) or by a DC discharge in a mixture of bismuth vapor and hydrogen in a fast-flow system were studied in the wavenumber range from 4000 to 25 000 cm-1 with a Fourier-transform spectrometer. The X21 → X10+ transition between the spin components of the X3Σ- ground state was remeasured at high spectral resolution and signal/noise. Six bands of the Δv = 0 and +1 sequences near 4950 and 6600 cm-1 have been observed. The low-J lines of these bands are split into up to 10 hfs components due to magnetic hyperfine structure splitting of the X21 levels. In addition to the previously observed electric dipole lines, weak magnetic dipole lines show up in the Δv = 0 but not in the Δv = +1 bands. The intensities of the Δv = +1 bands are about a factor of 10 higher than expected from Franck-Condon factors indicating that the electric dipole transition moment μX2-X1 shows a strong dependence on internuclear distance. Near 5450 cm-1, the 0-0 and 1-1 bands of the transition a2 → X21 from the hitherto unknown first excited state a1Δ(a2) to the upper component of the ground state have been observed. The lines in these bands show the magnetic hfs splitting of both the a2 and X21 states. In the visible range near 21 300 and 16 300 cm-1, the 0-0 and 1-1 bands of the b0+ → X10+ system and the 0-0 band of the b0+ → X21 transition likewise have been measured at high resolution. The lines of the latter band also show the hfs splitting of the X21 state. Least-squares fits have yielded rotational and vibrational constants of the X10+, X21, a2, and b0+ states as well as hfs parameters of the X21 and a2 states and the electronic energy of the hitherto unknown a1Δ(a2) level.

  8. Experimental study of heavy-ion computed tomography using a scintillation screen and an electron-multiplying charged coupled device camera for human head imaging

    NASA Astrophysics Data System (ADS)

    Muraishi, Hiroshi; Hara, Hidetake; Abe, Shinji; Yokose, Mamoru; Watanabe, Takara; Takeda, Tohoru; Koba, Yusuke; Fukuda, Shigekazu

    2016-03-01

    We have developed a heavy-ion computed tomography (IonCT) system using a scintillation screen and an electron-multiplying charged coupled device (EMCCD) camera that can measure a large object such as a human head. In this study, objective with the development of the system was to investigate the possibility of applying this system to heavy-ion treatment planning from the point of view of spatial resolution in a reconstructed image. Experiments were carried out on a rotation phantom using 12C accelerated up to 430 MeV/u by the Heavy-Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS). We demonstrated that the reconstructed image of an object with a water equivalent thickness (WET) of approximately 18 cm was successfully achieved with the spatial resolution of 1 mm, which would make this IonCT system worth applying to the heavy-ion treatment planning for head and neck cancers.

  9. Electron, Muon, and Tau Heavy Lepton--Are These the Truly Elementary Particles?

    ERIC Educational Resources Information Center

    Perl, Martin L.

    1980-01-01

    Discussed is the present concept of the ultimate nature of matter--the elementary particle. An explanation is given for why the lepton family of particles--the electron, muon, and tau--may be truly elementary. The tau lepton is described in more detail. (Author/DS)

  10. Electron structure of molecules with very heavy atoms using effective core potentials

    SciTech Connect

    Pitzer, K.S.

    1982-01-01

    Topics covered include effective potential, Hamiltonian for valence-electron motion, molecular calculations, spin-spin coupling, L-S coupling, numerical results of molecular calculations, and results of configuration-interaction Slater-orbital calculations in L-S coupling. (GHT)

  11. 77 FR 30765 - Federal Motor Vehicle Safety Standards; Electronic Stability Control Systems for Heavy Vehicles

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-23

    ...This document proposes to establish a new Federal Motor Vehicle Safety Standard No. 136 to require electronic stability control (ESC) systems on truck tractors and certain buses with a gross vehicle weight rating of greater than 11,793 kilograms (26,000 pounds). ESC systems in truck tractors and large buses are designed to reduce untripped rollovers and mitigate severe understeer or oversteer......

  12. Electron impact excitation and assignment of the low-lying electronic states of CO2

    NASA Technical Reports Server (NTRS)

    Hall, R. I.; Trajmar, S.

    1973-01-01

    Electron scattering spectra of CO2 are reported in the 7 to 10 eV energy-loss range, at energies of 0.2, 0.35, 0.6, 0.7, and 7.0 eV above threshold, and at a scattering angle of 90 deg. Several new distinct overlapping continua with weak, diffuse bands superimposed are observed to lie in this energy-loss range. The experimental spectra are discussed in the light of recent ab initio configuration-interaction calculations of the vertical transition energies of CO2. The experimental spectra are shown to be consistent with the excitation states of CO2.

  13. Measurement of the electronic momentum distributions of Rydberg Stark states

    SciTech Connect

    Murray-Krezan, J.; Jones, R. R.

    2007-06-15

    Approximate momentum distributions of Rydberg electrons in static electric fields have been obtained using an improved impulsive momentum retrieval (IMR) technique. An imaging detector enables the measurement of half-cycle pulse (HCP) ionization probability across the spatial profile of a focused half-cycle pulse beam. By modulating the HCP amplitude we directly measure the derivative of the ionization vs HCP impulse curve, enabling the recovery of momentum distributions with better resolution than previously demonstrated with IMR. For example, for Stark states with small dipole moments, we observe predicted fine-structure in the projection of the momentum distribution along the Stark field axis. We use a semiclassical model to simulate the effect that the nonzero HCP duration has on our measurements. Good agreement between simulated and measured momentum distributions is obtained.

  14. Electronic states of cuprate superconductors containing halogen or carbon

    NASA Astrophysics Data System (ADS)

    Tohiyama, Takami; Shibata, Yasumasa; Maekawa, Sadamichi

    1996-12-01

    The electronic states of the halo-oxocuprate and oxycarbonate superconductors are examined by means of the ionic and cluster models. The oxycarbonates examined contain the CO3 group on one side of the CuO2 plane. The superconducting critical temperature Tc is found to be correlated with the stability of the Zhang-Rice local singlet in the CuO2 plane. The stability is generally determined by two factors: (1) the energy-level separation between apical ion and in-plane oxygen and (2) the hybridization between apical pz and in-plane orbitals. The former is dominant for the oxycarbonates. It is also found that the CO3 group has no effect on the stabilization. For the halo-oxocuprates, the latter is crucial to stabilize the singlet.

  15. Ground state heavy baryon production in a relativistic quark-diquark model

    SciTech Connect

    Gomshi Nobary, M. A.; Sepahvand, R.

    2007-12-01

    We use current-current interaction to calculate the fragmentation functions to describe the production of spin-1/2, spin-1/2{sup '}, and spin-3/2 baryons with massive constituents in a relativistic quark-diquark model. Our results are in their analytic forms and are applicable for singly, doubly, and triply heavy baryons. We discuss the production of {omega}{sub bbc}, {omega}{sub bcc}, and {omega}{sub ccc} baryons in some detail. The results are satisfactorily compared with those obtained for triply heavy baryons calculated in a perturbative regime within reasonable values of the parameters involved.

  16. Ultrafast excited state relaxation dynamics of electron deficient porphyrins: Conformational and electronic factors

    NASA Astrophysics Data System (ADS)

    Okhrimenko, Albert N.

    Metallo-tetrapyrroles (MTP) are highly stable macrocyclic pi-systems that display interesting properties that make them potential candidates for various applications. Among these applications are optoelectronics, magnetic materials, photoconductive materials, non-linear optical materials and photo tumor therapeutic drugs. These applications are generally related to their high stability and efficient light absorption ability in the visible and near-infrared region of the optical spectrum. Metallo porphyrins are well known and widely studied representatives of metallotetrapyrroles. Electron deficient substituents in the meso positions are well known to greatly influence the interaction between the metal d-orbitals and the nitrogen orbitals of the tetrapyrrole macrocycle. In this work, a series of electron deficient porphyrins has been studied to gain some knowledge about the change in the excited state dynamics with structural and electronic modifications. Among these porphyrins is nickel and iron modified species bearing perfluoro-, perprotio-, p-nitrophenyl- and perfluorophenyl-meso substituents. Ultrafast transient absorption spectrometry has been used as the main research instrument along with other spectroscopic and electrochemical methods. A new technique has been employed to study the photophysical properties of zinc (II) tetraphenylporphine cation radical. It employs a combination of controlled potential coulometry and femtosecond absorption spectrometry. The fast transient lifetime of 17 ps of the pi-cation species originates in very efficient mixing of the a2u HOMO cation orbital that places electronic density mainly on pyrrolic nitrogens and metal d-orbitals. That explains the lack of any emission of the cationic species. This non-radiative decay process might elucidate the processes taking place in photosynthetic systems when electron is removed from porphyrinic moiety and the hole is produced. In this work zinc(II) meso-tetraphenylporphine radial cation

  17. Precursor anion states in dissociative electron attachment to chlorophenol isomers.

    PubMed

    Kossoski, F; Varella, M T do N

    2016-07-28

    We report a theoretical study on low-energy (<10 eV) elastic electron scattering from chlorophenol isomers, namely, para-chlorophenol (pCP), meta-chlorophenol (mCP), and ortho-chlorophenol (oCP). The calculations were performed with the Schwinger multichannel method with pseudopotentials, and analysis of the computed integral cross sections and virtual orbitals revealed one σCCl (∗), one σOH (∗), and three π(∗) shape resonances. We show that electron capture into the two lower lying π(∗) orbitals initiates dissociative processes that lead to the elimination of the chloride ion, accounting for the two overlapping peaks where this fragment was observed. Despite the relatively small differences on the energetics of the π(∗) resonances, a major isomeric effect was found on their corresponding autodetachment lifetimes, which accounts for the observed increasing cross sections in the progression pCP < mCP < oCP. In particular, dissociation from the π1 (∗) anion of pCP is largely suppressed because of the unfavorable mixing with the σCCl (∗) state. We found the intramolecular hydrogen bond present in oCP to have the opposite effects of stabilizing the σCCl (∗) resonance and destabilizing the σOH (∗) resonance. We also suggest that the hydrogen abstraction observed in chlorophenols and phenol actually takes place by a mechanism in which the incoming electron is directly attached to the dissociative σOH (∗) orbital. PMID:27475364

  18. Optical Properties and Electronic States Specific to Solid Fullerene

    NASA Astrophysics Data System (ADS)

    Minami, Nobutsugu; Kazaoui, Said; Wen, Ching-Ju; Byrne, Hugh J.

    1996-03-01

    One of the most intriguing aspects of the fullerene research is to ask what specific phenomena will occur when the soccer-ball shaped molecules aggregate and make a solid. Seeking this question is crucial for the realization of any photonic and electronic application of this new type of carbon allotrope. We have been working on this theme by the study of optical and electrical properties of C60 thin film. An important result is the demonstration of a distinct intermolecular charge transfer excited state (CT exciton) originating from intermolecular electronic interaction specific to the spherical pai conjugation system. This has been shown by the coincidence in the threshold energy of 2.3eV for absorption, luminescence efficiency, field induced luminescence quenching, and photoconductivity. We also found an evidence of the interconnection between optical properties and the structural phase transition at 260K. Moreover, a composite film containing C60 is demonstrated to show intense luminescence under 10mW laser irradiation.

  19. Coincidence measurements between fragment ions and the number of emitted electrons in heavy ion collisions with polyatomic molecules

    NASA Astrophysics Data System (ADS)

    Murai, T.; Majima, T.; Kishimoto, T.; Tsuchida, H.; Itoh, A.

    2012-11-01

    We have studied multiple ionization and multifragmentation of a chlorofluorocarbon molecule, CH2FCF3, induced by collisions of 580-keV C+ ions. Coincidence measurements of product ions and the number of emitted electrons from CH2FCF3 were performed under charge-changing conditions of C+ → Cq+ (q = 0, 2, 3). A fully inclusive measurement regardless of outgoing projectile charge state was also performed by making coincidence with a pulsed ion beam. Mass distributions of fragment ions and number distributions of emitted electrons were both found to change greatly according to charge-changing conditions. Highly multiple ionization emitting up to about 10 electrons was observed in electron loss collisions.

  20. Electron beam evaporation of molybdenum, yttrium and zirconium targets for heavy-ion nuclear physics

    SciTech Connect

    Greene, J.P.; Thomas, G.E.

    1990-01-01

    Self-supporting targets of {sup 92,98}Mo, Y and {sup 90}Zr with thickness of 100 and 200 {mu}g/cm{sup 2} were prepared by electron beam gun evaporation. Substrate heating proved crucial for the production of these foils. The numerous parting agents explored will be discussed. Targets of {sup 92,98}Mo were also prepared on carbon backings of various thickness. 19 refs., 2 figs.

  1. Religiosity, Heavy Alcohol Use, and Vicarious Learning Networks among Adolescents in the United States

    ERIC Educational Resources Information Center

    Gryczynski, Jan; Ward, Brian W.

    2012-01-01

    Previous research has found that religiosity may protect against risky alcohol and drug use behaviors among adolescents, but the social mechanics underpinning the relationship are not well understood. This study examined the relationship between religiosity, heavy drinking, and social norms among U.S. adolescents aged 12 to 17 years, using the…

  2. NEW EQUATIONS OF STATE BASED ON THE LIQUID DROP MODEL OF HEAVY NUCLEI AND QUANTUM APPROACH TO LIGHT NUCLEI FOR CORE-COLLAPSE SUPERNOVA SIMULATIONS

    SciTech Connect

    Furusawa, Shun; Yamada, Shoichi; Sumiyoshi, Kohsuke; Suzuki, Hideyuki

    2013-08-01

    We construct new equations of state for baryons at subnuclear densities for the use in core-collapse simulations of massive stars. The abundance of various nuclei is obtained together with thermodynamic quantities. A model free energy is constructed, based on the relativistic mean field theory for nucleons and the mass formula for nuclei with the proton number up to {approx}1000. The formulation is an extension of the previous model, in which we adopted the liquid drop model to all nuclei under the nuclear statistical equilibrium. We reformulate the new liquid drop model so that the temperature dependences of bulk energies could be taken into account. Furthermore, we extend the region in the nuclear chart, in which shell effects are included, by using theoretical mass data in addition to experimental ones. We also adopt a quantum-theoretical mass evaluation of light nuclei, which incorporates the Pauli- and self-energy shifts that are not included in the ordinary liquid drop model. The pasta phases for heavy nuclei are taken into account in the same way as in the previous model. We find that the abundances of heavy nuclei are modified by the shell effects of nuclei and temperature dependence of bulk energies. These changes may have an important effect on the rates of electron captures and coherent neutrino scatterings on nuclei in supernova cores. The abundances of light nuclei are also modified by the new mass evaluation, which may affect the heating and cooling rates of supernova cores and shocked envelopes.

  3. Direct electron-pair production by high energy heavy charged particles

    NASA Technical Reports Server (NTRS)

    Takahashi, Y.; Gregory, J. C.; Hayashi, T.; Dong, B. L.

    1989-01-01

    Direct electron pain production via virtual photons by moving charged particles is a unique electro-magnetic process having a substantial dependence on energy. Most electro-magnetic processes, including transition radiation, cease to be sensitive to the incident energy above 10 TeV/AMU. Thus, it is expected, that upon establishment of cross section and detection efficiency of this process, it may provide a new energy measuring technique above 10 TeV/AMU. Three accelerator exposures of emulsion chambers designed for measurements of direct electron-pains were performed. The objectives of the investigation were to provide the fundamental cross-section data in emulsion stacks to find the best-fit theoretical model, and to provide a calibration of measurements of direct electron-pairs in emulsion chamber configurations. This paper reports the design of the emulsion chambers, accelerator experiments, microscope measurements, and related considerations for future improvements of the measurements, and for possible applications to high energy cosmic ray experiments. Also discussed are the results from scanning 56m of emulsion tracks at 1200x magnification so that scanning efficiency is optimized. Measurements of the delta-ray range spectrum were also performed for much shorter track lengths, but with sufficiently large statistics in the number of measured delta-rays.

  4. Commensurate and incommensurate spin-density waves in heavy electron systems

    NASA Astrophysics Data System (ADS)

    Schlottmann, P.

    2016-05-01

    The nesting of the Fermi surfaces of an electron and a hole pocket separated by a nesting vector Q and the interaction between electrons gives rise to itinerant antiferromagnetism. The order can gradually be suppressed by mismatching the nesting and a quantum critical point (QCP) is obtained as the Néel temperature tends to zero. The transfer of pairs of electrons between the pockets can lead to a superconducting dome above the QCP (if Q is commensurate with the lattice, i.e. equal to G/2). If the vector Q is not commensurate with the lattice there are eight possible phases: commensurate and incommensurate spin and charge density waves and four superconductivity phases, two of them with modulated order parameter of the FFLO type. The renormalization group equations are studied and numerically integrated. A re-entrant SDW phase (either commensurate or incommensurate) is obtained as a function of the mismatch of the Fermi surfaces and the magnitude of |Q - G/2|.

  5. Electronic States of Nickel Effected By Magnetic Doping

    NASA Astrophysics Data System (ADS)

    Podolak, Ken; Smith, Jamie

    2012-02-01

    Spin currents have a great potential to replace charge currents. This would revolutionize how we read/write information. The generation and switching of spin currents however must be well understood. Transport measurements suggest that magnetic impurities can alter the mean free path of carriers and thereby create spin currents. Angle-resolved photoemission is used to determine the change in the electronic states of Ni induced by doping with iron, chromium, and manganese near the Fermi Energy. The samples were single crystals of nickel(110) with variable amounts of dopant diffused into it. Alloy single crystals were used over epitaxial thin films due to the sharper features at the Fermi Energy that they produced. The mean free path, magnetic splitting, and carrier density are affected by a few percent of each of the dopants. Iron suppresses the mean free path of minority spins only, while chromium and manganese suppresses both spins and decreases the magnetic splitting. The strong variation of these affects from one impurity to the other supports the concept of tailoring spin transport by magnetic doping. [1] K. N. Altmann et al., Phys. Rev. Lett. 87, 137201 (2001) [2] K.R. Podolak, Ph.D. Thesis, Penn. State (2008)

  6. Electron momentum spectroscopy of dimethyl ether taking account of nuclear dynamics in the electronic ground state

    NASA Astrophysics Data System (ADS)

    Morini, Filippo; Watanabe, Noboru; Kojima, Masataka; Deleuze, Michael Simon; Takahashi, Masahiko

    2015-10-01

    The influence of nuclear dynamics in the electronic ground state on the (e,2e) momentum profiles of dimethyl ether has been analyzed using the harmonic analytical quantum mechanical and Born-Oppenheimer molecular dynamics approaches. In spite of fundamental methodological differences, results obtained with both approaches consistently demonstrate that molecular vibrations in the electronic ground state have a most appreciable influence on the momentum profiles associated to the 2b1, 6a1, 4b2, and 1a2 orbitals. Taking this influence into account considerably improves the agreement between theoretical and newly obtained experimental momentum profiles, with improved statistical accuracy. Both approaches point out in particular the most appreciable role which is played by a few specific molecular vibrations of A1, B1, and B2 symmetries, which correspond to C-H stretching and H-C-H bending modes. In line with the Herzberg-Teller principle, the influence of these molecular vibrations on the computed momentum profiles can be unraveled from considerations on the symmetry characteristics of orbitals and their energy spacing.

  7. Electron momentum spectroscopy of dimethyl ether taking account of nuclear dynamics in the electronic ground state.

    PubMed

    Morini, Filippo; Watanabe, Noboru; Kojima, Masataka; Deleuze, Michael Simon; Takahashi, Masahiko

    2015-10-01

    The influence of nuclear dynamics in the electronic ground state on the (e,2e) momentum profiles of dimethyl ether has been analyzed using the harmonic analytical quantum mechanical and Born-Oppenheimer molecular dynamics approaches. In spite of fundamental methodological differences, results obtained with both approaches consistently demonstrate that molecular vibrations in the electronic ground state have a most appreciable influence on the momentum profiles associated to the 2b1, 6a1, 4b2, and 1a2 orbitals. Taking this influence into account considerably improves the agreement between theoretical and newly obtained experimental momentum profiles, with improved statistical accuracy. Both approaches point out in particular the most appreciable role which is played by a few specific molecular vibrations of A1, B1, and B2 symmetries, which correspond to C-H stretching and H-C-H bending modes. In line with the Herzberg-Teller principle, the influence of these molecular vibrations on the computed momentum profiles can be unraveled from considerations on the symmetry characteristics of orbitals and their energy spacing. PMID:26450316

  8. Electron momentum spectroscopy of dimethyl ether taking account of nuclear dynamics in the electronic ground state

    SciTech Connect

    Morini, Filippo; Deleuze, Michael Simon; Watanabe, Noboru; Kojima, Masataka; Takahashi, Masahiko

    2015-10-07

    The influence of nuclear dynamics in the electronic ground state on the (e,2e) momentum profiles of dimethyl ether has been analyzed using the harmonic analytical quantum mechanical and Born-Oppenheimer molecular dynamics approaches. In spite of fundamental methodological differences, results obtained with both approaches consistently demonstrate that molecular vibrations in the electronic ground state have a most appreciable influence on the momentum profiles associated to the 2b{sub 1}, 6a{sub 1}, 4b{sub 2}, and 1a{sub 2} orbitals. Taking this influence into account considerably improves the agreement between theoretical and newly obtained experimental momentum profiles, with improved statistical accuracy. Both approaches point out in particular the most appreciable role which is played by a few specific molecular vibrations of A{sub 1}, B{sub 1}, and B{sub 2} symmetries, which correspond to C–H stretching and H–C–H bending modes. In line with the Herzberg-Teller principle, the influence of these molecular vibrations on the computed momentum profiles can be unraveled from considerations on the symmetry characteristics of orbitals and their energy spacing.

  9. Role of electron energy loss in modification of C60 thin films by swift heavy ions

    NASA Astrophysics Data System (ADS)

    Bajwa, Navdeep; Ingale, Alka; Avasthi, D. K.; Kumar, Ravi; Tripathi, A.; Dharamvir, Keya; Jindal, V. K.

    2008-09-01

    This paper presents a comparative study of the effects of irradiation by swift heavy ions (SHIs) with Se values ranging from 80 to 1270 eV/Å and fluence ranges varying between 1010 and 1014 ions/cm2 incident on thin films of C60. The control over Se is exercised through the choice of ion species for irradiation (O, Ni, and Au). Structural changes in C60 were investigated quantitatively using Raman spectroscopy. The results indicate that at low fluences polymer formation takes place whereas at high fluences there is complete fragmentation of C60, resulting in amorphous carbon formation. Measured values of band gap and in situ resistivity decrease with fluence. This result is consistent with the structural modifications observed by Raman spectroscopy. The composition of the polymer fraction formed (e.g., the content of two dimensional polymerized network of C60 molecules) as well as that of a-C (e.g., the content of nanographite) also vary with Se of the ion used. A phenomenological model, taking into account the ion track, enables us to explain the trend of polymer formation as well as fragmentation of C60, with increasing fluence of SHI. The cross section for damage (fragmentation of C60 molecules) has two values—one effective at low fluences and the other at high fluences. By arriving at a quantitative formula giving the fraction of polymer/damaged C60 molecules at any given fluence, we are able to predict the fluence and ion species required for a given amount of polymerization/damage or vice versa. Effort has been made to correlate Se and Sn values to the damage cross sections using data from this work along with those from other experiments using keV and MeV ions.

  10. Excited state structural dynamics in higher lying electronic states: S2 state of malachite green

    NASA Astrophysics Data System (ADS)

    Laptenok, Sergey P.; Addison, Kiri; Heisler, Ismael A.; Meech, Stephen R.

    2014-06-01

    The S2 fluorescence of malachite green is measured with sub 100 fs time resolution. Ultrafast spectral dynamics in the S2 state preceding S2 decay are resolved. Measurements in different solvents show that these sub 100 fs dynamics are insensitive to medium polarity and viscosity. They are thus assigned to ultrafast structural evolution between the S2 Franck-Condon and equilibrium configurations.

  11. Time Modulation of the K-Shell Electron Capture Decay Rates of H-like Heavy Ions at GSI Experiments

    SciTech Connect

    Ivanov, A. N.; Kienle, P.

    2009-08-07

    According to experimental data at GSI, the rates of the number of daughter ions, produced by the nuclear K shell electron capture decays of the H-like heavy ions with one electron in the K shell, such as {sup 140}Pr{sup 58+}, {sup 142}Pm{sup 60+}, and {sup 122}I{sup 52+}, are modulated in time with periods T{sub EC} of the order of a few seconds, obeying an A scaling T{sub EC}=A/20 s, where A is the mass number of the mother nuclei, and with amplitudes a{sub d}{sup EC}approx0.21. We show that these data can be explained in terms of the interference of two massive neutrino mass eigenstates. The appearance of the interference term is due to overlap of massive neutrino mass eigenstate energies and of the wave functions of the daughter ions in two-body decay channels, caused by the energy and momentum uncertainties introduced by time differential detection of the daughter ions in GSI experiments.

  12. The electron-furfural scattering dynamics for 63 energetically open electronic states.

    PubMed

    da Costa, Romarly F; do N Varella, Márcio T; Bettega, Márcio H F; Neves, Rafael F C; Lopes, Maria Cristina A; Blanco, Francisco; García, Gustavo; Jones, Darryl B; Brunger, Michael J; Lima, Marco A P

    2016-03-28

    We report on integral-, momentum transfer- and differential cross sections for elastic and electronically inelastic electron collisions with furfural (C5H4O2). The calculations were performed with two different theoretical methodologies, the Schwinger multichannel method with pseudopotentials (SMCPP) and the independent atom method with screening corrected additivity rule (IAM-SCAR) that now incorporates a further interference (I) term. The SMCPP with N energetically open electronic states (N(open)) at either the static-exchange (N(open) ch-SE) or the static-exchange-plus-polarisation (N(open) ch-SEP) approximation was employed to calculate the scattering amplitudes at impact energies lying between 5 eV and 50 eV, using a channel coupling scheme that ranges from the 1ch-SEP up to the 63ch-SE level of approximation depending on the energy considered. For elastic scattering, we found very good overall agreement at higher energies among our SMCPP cross sections, our IAM-SCAR+I cross sections and the experimental data for furan (a molecule that differs from furfural only by the substitution of a hydrogen atom in furan with an aldehyde functional group). This is a good indication that our elastic cross sections are converged with respect to the multichannel coupling effect for most of the investigated intermediate energies. However, although the present application represents the most sophisticated calculation performed with the SMCPP method thus far, the inelastic cross sections, even for the low lying energy states, are still not completely converged for intermediate and higher energies. We discuss possible reasons leading to this discrepancy and point out what further steps need to be undertaken in order to improve the agreement between the calculated and measured cross sections. PMID:27036451

  13. The electron-furfural scattering dynamics for 63 energetically open electronic states

    NASA Astrophysics Data System (ADS)

    da Costa, Romarly F.; do N. Varella, Márcio T.; Bettega, Márcio H. F.; Neves, Rafael F. C.; Lopes, Maria Cristina A.; Blanco, Francisco; García, Gustavo; Jones, Darryl B.; Brunger, Michael J.; Lima, Marco A. P.

    2016-03-01

    We report on integral-, momentum transfer- and differential cross sections for elastic and electronically inelastic electron collisions with furfural (C5H4O2). The calculations were performed with two different theoretical methodologies, the Schwinger multichannel method with pseudopotentials (SMCPP) and the independent atom method with screening corrected additivity rule (IAM-SCAR) that now incorporates a further interference (I) term. The SMCPP with N energetically open electronic states (Nopen) at either the static-exchange (Nopen ch-SE) or the static-exchange-plus-polarisation (Nopen ch-SEP) approximation was employed to calculate the scattering amplitudes at impact energies lying between 5 eV and 50 eV, using a channel coupling scheme that ranges from the 1ch-SEP up to the 63ch-SE level of approximation depending on the energy considered. For elastic scattering, we found very good overall agreement at higher energies among our SMCPP cross sections, our IAM-SCAR+I cross sections and the experimental data for furan (a molecule that differs from furfural only by the substitution of a hydrogen atom in furan with an aldehyde functional group). This is a good indication that our elastic cross sections are converged with respect to the multichannel coupling effect for most of the investigated intermediate energies. However, although the present application represents the most sophisticated calculation performed with the SMCPP method thus far, the inelastic cross sections, even for the low lying energy states, are still not completely converged for intermediate and higher energies. We discuss possible reasons leading to this discrepancy and point out what further steps need to be undertaken in order to improve the agreement between the calculated and measured cross sections.

  14. Heavy atom nitroxyl radicals. VI. The electronic spectrum of jet-cooled H2PO, the prototypical phosphoryl free radical

    NASA Astrophysics Data System (ADS)

    Gharaibeh, Mohammed A.; Clouthier, Dennis J.; Tarroni, Riccardo

    2011-12-01

    The previously unknown electronic spectrum of the H2PO free radical has been identified in the 407-337 nm region using a combination of laser-induced fluorescence and single vibronic level emission spectroscopy. High level ab initio predictions of the properties of the ground and first two excited doublet states were used to identify the spectral region in which to search for the electronic transition and were used to aid in the analysis of the data. The band system is assigned as the {tilde B}2A'-{tilde X}2A' electronic transition which involves promotion of an electron from the π to the π* molecular orbital. The excited state r0 molecular structure was determined by rotational analysis of high resolution LIF spectra to be r(PO) = 1.6710(2) Å, r(PH) = 1.4280(6) Å, θ(HPO) = 105.68(7)°, θ(HPH) = 93.3(2)°, and the out-of-plane angle = 66.8(2)°. The structural changes on electronic excitation, which include substantial increases in the PO bond length and out-of-plane angle, are as expected based on molecular orbital theory and our previous studies of the isoelectronic H2AsO, Cl2PS, and F2PS free radicals.

  15. A new 14 GHz Electron-Cyclotron-Resonance Ion Source (ECRIS) for the heavy ion accelerator facility ATLAS

    SciTech Connect

    Schlapp, M.; Pardo, R.C.; Vondrasek, R.C.; Billquist, P.J.; Szczech, J.

    1997-11-01

    A 14 GHz Electron-Cyclotron-Resonance Ion Source (ECRIS) has been designed and built at Argonne National Laboratory. The source is a modification of the AECR at Berkeley and incorporates the latest results from ECR developments to produce intense beams of highly charged ions, including an improved magnetic confinement of the plasma electrons with an axial mirror ratio of 3.5. The aluminum plasma chamber and extraction electrode as well as a biased disk on axis at the microwave injection side donates additional electrons to the plasma, making use of the large secondary electron yield from aluminum oxide. The source is capable of ECR plasma heating using two different frequencies simultaneously to increase the electron energy gain for the production of high charge states. The main design goal is to produce several e{mu}A of at least {sup 238}U{sup 35+} in order to accelerate the beam to coulomb-barrier energies without further stripping. First charge state distributions for gaseous elements have been measured and 210 e{mu}A {sup 16}O{sup 7+} has been achieved. A normalized 90% emittance from 0.1 to 0.2 {pi} mm{sm_bullet}mrad for krypton and oxygen beam has been found.

  16. Generation of high charge state metal ion beams by electron cyclotron resonance heating of vacuum arc plasma in cusp trap

    SciTech Connect

    Nikolaev, A. G.; Savkin, K. P.; Oks, E. M.; Vizir, A. V.; Yushkov, G. Yu.; Vodopyanov, A. V.; Izotov, I. V.; Mansfeld, D. A.

    2012-02-15

    A method for generating high charge state heavy metal ion beams based on high power microwave heating of vacuum arc plasma confined in a magnetic trap under electron cyclotron resonance conditions has been developed. A feature of the work described here is the use of a cusp magnetic field with inherent ''minimum-B'' structure as the confinement geometry, as opposed to a simple mirror device as we have reported on previously. The cusp configuration has been successfully used for microwave heating of gas discharge plasma and extraction from the plasma of highly charged, high current, gaseous ion beams. Now we use the trap for heavy metal ion beam generation. Two different approaches were used for injecting the vacuum arc metal plasma into the trap - axial injection from a miniature arc source located on-axis near the microwave window, and radial injection from sources mounted radially at the midplane of the trap. Here, we describe preliminary results of heating vacuum arc plasma in a cusp magnetic trap by pulsed (400 {mu}s) high power (up to 100 kW) microwave radiation at 37.5 GHz for the generation of highly charged heavy metal ion beams.

  17. Harvesting singlet fission for solar energy conversion: one versus two-electron transfer electron transfer from the quantum superposition state

    NASA Astrophysics Data System (ADS)

    Chan, Wai-Lun; Tritsch, John; Zhu, Xiaoyang

    2013-03-01

    Singlet fission (SF) is being explored to increase the efficiency of organic photovoltaics. A key question is how to effectively extract multiple electron-hole pairs from multiple excitons with the presence of other competing channels such as electron transfer from the singlet state. Recent experiments on the pentacene and tetracene show that a quantum superposition of the singlet (S1) and multiexciton (ME) state is formed during SF. However, little is known about the kinetics of electron transfer from this quantum superposition. Here, we apply time-resolved photoemission spectroscopy to the tetracene/C60 interface to probe one and two electron transfer from S1 and ME states, respectively. Because of the relatively slow (7 ps) SF in tetracene, both one- and two-electron transfer are allowed. We show evidence for the formation of two distinct charge transfer states due to electron transfer from photo-excited tetracene to the lowest unoccupied molecular orbital (LUMO) and the LUMO+1 levels in C60. Kinetic analysis shows that 60% of the quantum superposition transfers one electron through the S1 state to C60 while 40% undergoes two-electron transfer through the ME state.

  18. Interstellar propagation and electron capture processes of galactic cosmic ray heavy ions in space

    NASA Technical Reports Server (NTRS)

    Miltra, B.; Biswas, S.; Goswami, J. N.

    1995-01-01

    The new information on galactic cosmic rays (GCR) derived from the Spacelab-3 cosmic ray experiment 'Anuradha' shows that at 25-125 MeV/N GCR sub-iron and iron (Z = 21-28) particles consists of a mixture of partially ionized and fully ionized ions. Computation of electron capture and loss cross sections in hydrogen in 1-50 MeV/N energy range are made for Fe, Cr, Ti and Ni. From these it is concluded that: (1) these GCR particles must have captured orbital electrons at energies of about 1-5 MeV/N and (2) these particles are then reaccelerated to 300-500 MeV/N most probably in interstellar medium by collision with SNR shock fronts. Some reacceleration may take place also in heliospheric boundary region. It is suggested that these observations of partially ionized GCR ions of about 100 MeV/N in Spacelab-3 provide a direct evidence of reacceleration of GCR.

  19. Electronic ground state properties of Coulomb blockaded quantum dots

    NASA Astrophysics Data System (ADS)

    Patel, Satyadev Rajesh

    Conductance through quantum dots at low temperature exhibits random but repeatable fluctuations arising from quantum interference of electrons. The observed fluctuations follow universal statistics arising from the underlying universality of quantum chaos. Random matrix theory (RMT) has provided an accurate description of the observed universal conductance fluctuations (UCF) in "open" quantum dots (device conductance ≥e 2/h). The focus of this thesis is to search for and decipher the underlying origin of similar universal properties in "closed" quantum dots (device conductance ≤e2/ h). A series of experiments is presented on electronic ground state properties measured via conductance measurements in Coulomb blockaded quantum dots. The statistics of Coulomb blockade (CB) peak heights with zero and non-zero magnetic field measured in various devices agree qualitatively with predictions from Random Matrix Theory (RMT). The standard deviation of the peak height fluctuations for non-zero magnetic field is lower than predicted by RMT; the temperature dependence of the standard deviation of the peak height for non-zero magnetic field is also measured. The second experiment summarizes the statistics of CB peak spacings. The peak spacing distribution width is observed to be on the order of the single particle level spacing, Delta, for both zero and non-zero magnetic field. The ratio of the zero field peak spacing distribution width to the non-zero field peak spacing distribution width is ˜1.2; this is good agreement with predictions from spin-resolved RMT predictions. The standard deviation of the non-zero magnetic field peak spacing distribution width shows a T-1/2 dependence in agreement with a thermal averaging model. The final experiment summarizes the measurement of the peak height correlation length versus temperature for various quantum dots. The peak height correlation length versus temperature saturates in small quantum dots, suggesting spectral scrambling

  20. Two-Photon and Two-gluon Decays of 0{sup ++} and 2{sup ++} P-wave Heavy Quarkonium States

    SciTech Connect

    Pham, T. N.

    2010-12-22

    By neglecting the relative quark momenta in the propagator term, the two-photon and two-gluon decay amplitude of heavy quarkonia states can be written as a local heavy quark field operator matrix element which could be obtained from other processes or computed with QCD sum rules technique or lattice simulation, as shown in a recent work on {eta}{sub c,b} two-photon decays. In this talk, I would like to discuss a similar calculation on P-wave {chi}{sub c0,2} and {chi}{sub b0,2} two-photon decays. We show that the effective Lagrangian for the two-photon decays of the P-wave {eta}{sub c0,2} and {chi}{sub b0,2} is given by the heavy quark energy-momentum tensor local operator and its trace, the QQ scalar density. A simple expression for {chi}c0 two-photon and two-gluon decay rate in terms of the f{sub {chi}c0} decay constant, similar to that of {eta}{sub c} is obtained. From the existing QCD sum rules value for f{sub {chi}c0,} we get 5 keV for the {chi}{sub c0} two-photon width, somewhat larger than measurement.

  1. All-electron first principles calculations of the ground and some low-lying excited states of BaI.

    PubMed

    Miliordos, Evangelos; Papakondylis, Aristotle; Tsekouras, Athanasios A; Mavridis, Aristides

    2007-10-01

    The electronic structure of the heavy diatomic molecule BaI has been examined for the first time by ab initio multiconfigurational configuration interaction (MRCI) and coupled cluster (RCCSD(T)) methods. The effects of special relativity have been taken into account through the second-order Douglas-Kroll-Hess approximation. The construction of Omega(omega,omega) potential energy curves allows for the estimation of "experimental" dissociation energies (De) of the first few excited states by exploiting the accurately known De experimental value of the X2Sigma+ ground state. All states examined are of ionic character with a Mulliken charge transfer of 0.5 e- from Ba to I, and this is reflected to large dipole moments ranging from 6 to 11 D. Despite the inherent difficulties of a heavy system like BaI, our results are encouraging. With the exception of bond distances that on the average are calculated 0.05 A longer than the experimental ones, common spectroscopic parameters are in fair agreement with experiment, whereas De values are on the average 10 kcal/mol smaller. PMID:17850123

  2. Leaching behaviour and environmental risk assessment of heavy metals from electronic solder in acidified soil.

    PubMed

    Lao, Xiaodong; Cheng, Congqian; Min, Xiaohua; Zhao, Jie; Zhou, Dayu; Li, Xiaogang

    2015-11-01

    The leaching behaviour of Sn and Pb elements from eutectic SnPb solder of electronic waste in acidic soil was investigated through acidification with HCl-H2SO4 solution and compared with saline solution. The amounts of Sn and Pb elements leached, when subjected to acidic soil, are higher than those with saline soil. Evidence for the significantly preferential release of Sn into the leachate is provided; the galvanic couple accelerated such preferential release. Surface product analysis reveals the slight damage of SnPb in saline soil. Serious dissolution due to electrochemical reaction and a thick, porous PbSO4 surface layer are observed in acidified soil, suggesting more severe toxicity potential of Pb in soil rather than in water. PMID:26154035

  3. The Effect of Pressure on the Heavy-Electron Superconductors URANIUM-BERYLLIUM(13) and URANIUM-RUTHENIUM(2)SILICON(2)

    NASA Astrophysics Data System (ADS)

    McElfresh, Michael Wayne

    An investigation of the pressure dependence of the normal state properties of the heavy-electron superconductors UBe_{13} and URu _2Si_2 was undertaken in order to explore the relationship of Kondo lattice properties to the properties expected for dilute Kondo systems. The compound UBe_{13} was the second heavy-electron superconductor identified, having a superconducting transition temperature T _{c} cong 0.97 K and an electronic specific heat coefficient of 1100 mJ/mole -K^2. The electrical resistivity rho(T) was measured at pressures to 152 kbar showing two rates of increase in the temperature of the rho maximum T_ {max}, one rate of 0.25 K/kbar below ~30 kbar and a second rate of 0.65 K/kbar above ~30 kbar. At low temperatures rho(T) increases quadratically with temperature T, with the T range increasing from less than 1 K at 1 bar to over 16.5 K at 150 kbar. This T^2 dependence is characteristic of Fermi liquid behavior and the T^2 coefficient of rho(T) can be related to a characteristic temperature T_{sf}~ A^ {-1/2}. Both T_{max} and T_{sf} can be related to the width of the band at the Fermi level, and evidence of a simple relationship between T_{max} and T_{sf} is provided by the pressure dependence of these characteristic temperatures. Measurements of pressure dependent magnetic susceptibility are qualitatively consistent with an increase of the Kondo-related characteristic temperature with pressure. The compound URu_2Si _2 exhibits two electronic phase transitions: superconductivity at T_{c} cong 1.5 K and an itinerant antiferromagnetic transition at T_{o} cong 17.5 K. The specific heat anomaly at T_{o} has a mean -field BCS-like form characteristic of the formation of a gap at the Fermi surface. From pressure dependent resistivity rho(T) measurements to 15.4 kbar the effect of pressure was shown to decrease T _{c} at a rate of -95 mK/kbar and increase T_{ o} at a rate of 130 mK/kbar below 12 kbar and at a higher rate at pressures above 12 kbar. The

  4. Ionization states of heavy elements observed in the 1974 May 14-15 anomalous solar particle event

    NASA Technical Reports Server (NTRS)

    Ma Sung, L. S.; Gloeckler, G.; Fan, C. Y.; Hovestadt, D.

    1981-01-01

    The charge states of heavy ions accelerated in the (3)He-Fe rich solar particle event of 1974 May 14-15 are determined using data from the Interplanetary Monitoring Platform-8. In addition to Fe(+11,12) both 0(+5) and Fe(+16,17,18) are also present suggesting variations in coronal temperatures over a range from approximately 400,000 to 5,000,000 K. The presence of 0(+5) and Fe(+16-18) may be explained by a resonant plasma heating mechanism proposed to account for the enhancements of (3)He and Fe.

  5. Novel magnetic and electronic states in manganite-iridate heterostructures

    NASA Astrophysics Data System (ADS)

    Nichols, John; Lee, Shinbuhm; Petrie, Jon; Meyer, Tricia; Gao, Xiang; Guo, Erjia; Freeland, John; Yi, Di; Liu, Jian; Haskel, Daniel; Ward, Thomas Zac; Eres, Gyula; Lauter, Valeria; Fitzsimmons, Michael R.; Lee, Ho Nyung

    Strong correlation between spin, charge, lattice, and orbital order parameters has proven to give rise to exotic physical phenomena, while epitaxial design of materials with strong interfacial coupling is an efficient technique to tune such parameters. Although there have been numerous studies of interfaces between 3 d-3 d and 4 d-3 d compounds, only few studies reported work on 3 d and 5 d materials and there has been no report on strong interfacial coupling in such systems. We have synthesized high quality [(AMnO3)m /(SrIrO3)n ]z (A = Sr, La) heterostructures by pulsed laser epitaxy on SrTiO3 (001) substrates and have observed interesting novel magnetic and electronic ground states, which are highly sensitive to the degree of dimensional confinement in the heterostructures. Based on studies with x-ray diffraction, SQUID, dc-transport, x-ray circular dichroism, and polarized neutron reflectometry measurements, we will report intriguing magnetic and transport properties that provide the first evidence of strong interfacial coupling between 5 d and 3 d materials. This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division.

  6. Electronic structure of proteins and DNA: solid-state aspects.

    PubMed

    Ladik, J J

    1978-01-01

    The generalization of the Hartree-Fock method to periodic systems (polymers or crystals) using a linear combination of atomic orbitals (LCAO) makes it possible to calculate ab initio self-consistent-field LCAO band structures of periodic protein and DNA models. The results obtained for polyglycine, polyalanine, and for the mixed poly(Gly-Ala) periodic chain, as well as for the four homopolynucleotides, are presented. The correction of these band structures for excitonic effects (in the excited state) and for long-range correlation effects is shown also. Furthermore, it is outlined how the short-range correlation in insulator biopolymers and correlation effects in proteins with a partially filled valence band (for instance, due to charge transfer) can be calculated. The Coherent Potential Approximation is outlined and its possible application to aperiodic proteins and DNA is pointed out. Finally the effect of an electron acceptor on proteins or of a chemical carcinogen bound to DNA is discussed as a local perturbation of the band structures of these systems on the basis of the self-consistent resolvent method. PMID:259504

  7. Overlap of electron core states for very high compressions

    NASA Astrophysics Data System (ADS)

    Straub, G.

    At normal density and for modest compressions, the electronic structure of a metal can be accurately described by treating the conduction electrons and their interactions with the usual methods of band theory. The core electrons remain essentially the same as for an isolated free atom and do not participate in the bonding forces responsible for creating a condensed phase. As the density increases, the core electrons begin to see one another as the overlap of the tails of wave functions can no longer be neglected. The electronic structure of the core electrons is responsible for an effective repulsive interaction that eventually becomes free-electron-like at very high compressions. The electronic structure of the interacting core electrons may be treated in a simple manner using the Atomic Surface Method (ASM). The ASM is a first-principles treatment of the electronic structure involving a rigorous integration of the Schroedinger equation within the atomic-sphere approximation. Solid phase wave functions are constructed from isolated atom wave functions and the band width W sub 1 and the center of gravity of the band C sub 1 are obtained from simple formulas. The ASM can also utilize analytic forms of the atomic wave functions and thus provide direct functional dependence of various aspects of the electronic structure. Of particular use in understanding the behavior of the core electrons, the ASM provides the analytic density dependence of the band widths and positions.

  8. Extraction of a steady state electron beam from HCD (hollow cathode discharge) plasmas for EBIS (electron beam ion source) applications

    SciTech Connect

    Hershcovitch, A.; Kovarik, V.; Prelec, K.

    1988-01-01

    Experiments to extract high brightness electron beams from hollow cathode discharge plasmas are now in progress. A unique feature of these plasmas, which in principle can facilitate the extraction of large current low emittance electron beams, is the existence of a relatively high energy electron population with a very narrow energy spread. This electron population was identified in a self-extraction experiment, which yielded a 35 eV, 600 mA electron beam with parallel energy spread of less than 0.5 eV. Preliminary, crude application of 2.5 kV extraction voltage yielded a steady state electron beam current of 1.2 A. The end result of this endeavor would be an Electron Beam Ion Source (EBIS) with an electron beam current of 6 A. 4 refs., 2 figs.

  9. Centrality dependence of heavy flavor production from single electron measurement in √{S}=200 GeV Au +Au collisions

    NASA Astrophysics Data System (ADS)

    Bielcik, J.; STAR Collaboration

    2006-08-01

    We present preliminary measurements of electron production in p+p, d+Au, and Au+Au collisions at √{S}=200 GeV for transverse momenta 1.5 GeV/celectrons from hadrons and the method used to evaluate the non-photonic contributions from semi-leptonic decays of heavy flavor mesons. The observed nuclear modification factors, RAA, of non-photonic electrons indicate at substantial energy loss of heavy quarks at moderate to high pT.

  10. Electronic transport, density of states and ground state properties of Li In binary alloy

    NASA Astrophysics Data System (ADS)

    Kumar, Ashwani; Rafique, S. M.; Sinha, T. P.

    2008-10-01

    The electronic transport properties of Li-In binary alloy have been studied by Harrison's first principle pseudopotential technique. The Percus-Yevik hard sphere model is used to compute the partial structure factors S ij( k) for the alloy at the desired composition. We have also calculated the ground state properties of Li-In alloy employing full-potential linearized augmented plane wave (FLAPW) method. The equilibrium values of bulk modulus and its pressure derivative have been estimated through optimization of the crystal structure of the Li-In alloy. The calculated total density of states (DOS) and the partial DOS around the Fermi energy are used to explain the variation of resistivity of the alloy with carrier concentration.

  11. Minimal parametrization of an n-electron state

    SciTech Connect

    Kutzelnigg, Werner; Mukherjee, Debashis

    2005-02-01

    The Hamiltonian H for an n-electron system in a finite one-electron basis of dimension m is characterized by d=O(m{sup 4}) matrix elements. The eigenstates of this Hamiltonian - i.e., the full-CI states {psi} - depend, however, on the usually much larger set of N=O(m{sup n}) parameters. One can, nevertheless, write a full-CI state as {psi}=e{sup S}{phi} with {phi} a reference function and S an operator familiar from traditional coupled cluster (TCC) theory. The 'exact' operator S can be expressed (though in an implicit and rather complicated way) in terms of d parameters. An alternative ansatz {psi}=e{sup T}{phi} with T depending in a very simple way on d parameters only (namely, with T having the same structure in Fock space as H) has been studied by Nooijen and by Nakatsuji and been called coupled-cluster with generalized single and double excitations (CCGSD). Nooijen has conjectured that the full-CI equations can be fulfilled with this ansatz. This paper is devoted to a comprehensive analysis of the Nooijen conjecture (NC). Several features make this analysis difficult and even intriguing. (a) One deals with coupled nonlinear systems of equations, for which theorems concerning the existence of their solution are hardly available. (b) There are different possible interpretations of the NC, especially as far as the choice of the reference function {phi} is concerned. (c) There are solutions of the CCGSD equations, for which some elements of T becomes negative infinite, and e{sup T} becomes a projection operator. Such solutions are undesired but difficult to eliminate. We show by direct comparison of the exact wave operator with that of CCGSD theory, for a closed-shell state with {phi} a single Slater determinant, using a perturbation expansion, that CCGSD cannot be exact. This required a reformulation of the CCGSD operator e{sup T} to an equivalent exponential form e{sup R}, with R similar to the S of TCC theory, but with constraints on the cluster amplitudes

  12. STM probe on the surface electronic states of spin-orbit coupled materials

    NASA Astrophysics Data System (ADS)

    Zhou, Wenwen

    Spin-orbit coupling (SOC) is the interaction of an electron's intrinsic angular momentum (spin) with its orbital momentum. The strength of this interaction is proportional to Z4 where Z is the atomic number, so generally it is stronger in atoms with higher atomic number, such as bismuth (Z=83) and iridium (Z=77). In materials composed of such heavy elements, the prominent SOC can be sufficient to modify the band structure of the system and lead to distinct phase of matter. In recent years, SOC has been demonstrated to play a critical role in determining the unusual properties of a variety of compounds. SOC associated materials with exotic electronic states have also provided a fertile platform for studying emergent phenomena as well as new physics. As a consequence, the research on these interesting materials with any insight into understanding the microscopic origin of their unique properties and complex phases is of great importance. In this context, we implement scanning tunneling microscopy (STM) and spectroscopy (STS) to explore the surface states (SS) of the two major categories of SOC involved materials, Bi-based topological insulators (TI) and Ir-based transition metal oxides (TMO). As a powerful tool in surface science which has achieved great success in wide variety of material fields, STM/STS is ideal to study the local density of states of the subject material with nanometer length scales and is able to offer detailed information about the surface electronic structure. In the first part of this thesis, we report on the electronic band structures of three-dimensional TIs Bi2Te3 and Bi2Se 3. Topological insulators are distinct quantum states of matter that have been intensely studied nowadays. Although they behave like ordinary insulators in showing fully gapped bulk bands, they host a topologically protected surface state consisting of two-dimensional massless Dirac fermions which exhibits metallic behavior. Indeed, this unique gapless surface state is a

  13. Search for heavy particles decaying into electron-positron pairs in pp collisions.

    PubMed

    Abazov, V M; Abbott, B; Abdesselam, A; Abolins, M; Abramov, V; Acharya, B S; Adams, D L; Adams, M; Ahmed, S N; Alexeev, G D; Alves, G A; Amos, N; Anderson, E W; Baarmand, M M; Babintsev, V V; Babukhadia, L; Bacon, T C; Baden, A; Baldin, B; Balm, P W; Banerjee, S; Barberis, E; Baringer, P; Barreto, J; Bartlett, J F; Bassler, U; Bauer, D; Bean, A; Begel, M; Belyaev, A; Beri, S B; Bernardi, G; Bertram, I; Besson, A; Beuselinck, R; Bezzubov, V A; Bhat, P C; Bhatnagar, V; Bhattacharjee, M; Blazey, G; Blessing, S; Boehnlein, A; Bojko, N I; Borcherding, F; Bos, K; Brandt, A; Breedon, R; Briskin, G; Brock, R; Brooijmans, G; Bross, A; Buchholz, D; Buehler, M; Buescher, V; Burtovoi, V S; Butler, J M; Canelli, F; Carvalho, W; Casey, D; Casilum, Z; Castilla-Valdez, H; Chakraborty, D; Chan, K M; Chekulaev, S V; Cho, D K; Choi, S; Chopra, S; Christenson, J H; Chung, M; Claes, D; Clark, A R; Cochran, J; Coney, L; Connolly, B; Cooper, W E; Coppage, D; Cummings, M A; Cutts, D; Davis, G A; Davis, K; De, K; de Jong, S J; Del Signore, K; Demarteau, M; Demina, R; Demine, P; Denisov, D; Denisov, S P; Desai, S; Diehl, H T; Diesburg, M; Di Loreto, G; Doulas, S; Draper, P; Ducros, Y; Dudko, L V; Duensing, S; Duflot, L; Dugad, S R; Dyshkant, A; Edmunds, D; Ellison, J; Elvira, V D; Engelmann, R; Eno, S; Eppley, G; Ermolov, P; Eroshin, O V; Estrada, J; Evans, H; Evdokimov, V N; Fahland, T; Feher, S; Fein, D; Ferbel, T; Filthaut, F; Fisk, H E; Fisyak, Y; Flattum, E; Fleuret, F; Fortner, M; Frame, K C; Fuess, S; Gallas, E; Galyaev, A N; Gao, M; Gavrilov, V; Genik, R J; Genser, K; Gerber, C E; Gershtein, Y; Gilmartin, R; Ginther, G; Gómez, B; Gómez, G; Goncharov, P I; González Solís, J L; Gordon, H; Goss, L T; Gounder, K; Goussiou, A; Graf, N; Graham, G; Grannis, P D; Green, J A; Greenlee, H; Grinstein, S; Groer, L; Grünendahl, S; Gupta, A; Gurzhiev, S N; Gutierrez, G; Gutierrez, P; Hadley, N J; Haggerty, H; Hagopian, S; Hagopian, V; Hall, R E; Hanlet, P; Hansen, S; Hauptman, J M; Hays, C; Hebert, C; Hedin, D; Heinson, A P; Heintz, U; Heuring, T; Hildreth, M D; Hirosky, R; Hobbs, J D; Hoeneisen, B; Huang, Y; Illingworth, R; Ito, A S; Jaffré, M; Jain, S; Jesik, R; Johns, K; Johnson, M; Jonckheere, A; Jones, M; Jöstlein, H; Juste, A; Kahn, S; Kajfasz, E; Kalinin, A M; Karmanov, D; Karmgard, D; Kehoe, R; Kharchilava, A; Kim, S K; Klima, B; Knuteson, B; Ko, W; Kohli, J M; Kostritskiy, A V; Kotcher, J; Kotwal, A V; Kozelov, A V; Kozlovsky, E A; Krane, J; Krishnaswamy, M R; Krivkova, P; Krzywdzinski, S; Kubantsev, M; Kuleshov, S; Kulik, Y; Kunori, S; Kupco, A; Kuznetsov, V E; Landsberg, G; Leflat, A; Leggett, C; Lehner, F; Li, J; Li, Q Z; Lima, J G; Lincoln, D; Linn, S L; Linnemann, J; Lipton, R; Lucotte, A; Lueking, L; Lundstedt, C; Luo, C; Maciel, A K; Madaras, R J; Malyshev, V L; Manankov, V; Mao, H S; Marshall, T; Martin, M I; Martin, R D; Mauritz, K M; May, B; Mayorov, A A; McCarthy, R; McDonald, J; McMahon, T; Melanson, H L; Merkin, M; Merritt, K W; Miao, C; Miettinen, H; Mihalcea, D; Mishra, C S; Mokhov, N; Mondal, N K; Montgomery, H E; Moore, R W; Mostafa, M; da Motta, H; Nagy, E; Nang, F; Narain, M; Narasimham, V S; Neal, H A; Negret, J P; Negroni, S; Nunnemann, T; O'Neil, D; Oguri, V; Olivier, B; Oshima, N; Padley, P; Pan, L J; Papageorgiou, K; Para, A; Parashar, N; Partridge, R; Parua, N; Paterno, M; Patwa, A; Pawlik, B; Perkins, J; Peters, M; Peters, O; Pétroff, P; Piegaia, R; Piekarz, H; Pope, B G; Popkov, E; Prosper, H B; Protopopescu, S; Qian, J; Raja, R; Rajagopalan, S; Ramberg, E; Rapidis, P A; Reay, N W; Reucroft, S; Rha, J; Ridel, M; Rijssenbeek, M; Rockwell, T; Roco, M; Rubinov, P; Ruchti, R; Rutherfoord, J; Sabirov, B M; Santoro, A; Sawyer, L; Schamberger, R D; Schellman, H; Schwartzman, A; Sen, N; Shabalina, E; Shivpuri, R K; Shpakov, D; Shupe, M; Sidwell, R A; Simak, V; Singh, H; Singh, J B; Sirotenko, V; Slattery, P; Smith, E; Smith, R P; Snihur, R; Snow, G R; Snow, J; Snyder, S; Solomon, J; Sorín, V; Sosebee, M; Sotnikova, N; Soustruznik, K; Souza, M; Stanton, N R; Steinbrück, G; Stephens, R W; Stichelbaut, F; Stoker, D; Stolin, V; Stoyanova, D A; Strauss, M; Strovink, M; Stutte, L; Sznajder, A; Taylor, W; Tentindo-Repond, S; Tripathi, S M; Trippe, T G; Turcot, A S; Tuts, P M; van Gemmeren, P; Vaniev, V; Van Kooten, R; Varelas, N; Vertogradov, L S; Volkov, A A; Vorobiev, A P; Wahl, H D; Wang, H; Wang, Z M; Warchol, J; Watts, G; Wayne, M; Weerts, H; White, A; White, J T; Whiteson, D; Wightman, J A; Wijngaarden, D A; Willis, S; Wimpenny, S J; Womersley, J; Wood, D R; Yamada, R; Yamin, P; Yasuda, T; Yatsunenko, Y A; Yip, K; Youssef, S; Yu, J; Yu, Z; Zanabria, M; Zheng, H; Zhou, Z; Zielinski, M; Zieminska, D; Zieminski, A; Zutshi, V; Zverev, E G; Zylberstejn, A

    2001-08-01

    We present results of searches for technirho (rho(T)), techniomega (omega(T)), and Z' particles, using the decay channels rho(T),omega(T),Z'-->e(+)e(-). The search is based on 124.8 pb(-1) of data collected by the D0 detector at the Fermilab Tevatron during 1992-1996. In the absence of a signal, we set 95% C.L. upper limits on the cross sections for the processes pp-->rho(T),omega(T),Z'-->e(+)e(-) as a function of the mass of the decaying particle. For certain model parameters, we exclude the existence of degenerate rho(T) and omega(T) states with masses below about 200 GeV. We exclude a Z' with mass below 670 GeV, assuming that it has the same couplings to fermions as the Z boson. PMID:11497822

  14. Separating the Spin States of a Free Electron Beam

    NASA Astrophysics Data System (ADS)

    Rifkin, Neil

    2008-10-01

    In 1922 Otto Stern and Walther Gerlach set out to test the spacial quantization of the electron by passing a beam of neutral silver atoms through a transverse magnetic field. The interaction of the two projections of the electron's magnetic moment with the magnetic field resulted in a splitting of the beam. However, for some sixty years it was generally accepted that the spin of free electrons, and thus their magnetic moment, could not be measured with an experiment similar to that of Stern and Gerlach. The reason being that the lorentz force on charged particles is far greater than the force due to the magnetic moment of the electron, thus blurring any desired results. To reduce the lorentz force, the electrons could be passed through a magnetic field whose gradient is in the direction of the electrons' momentum. This longitudinal Stern-Gerlach device, with a superconducting magnet, could polarize the tails of a low energy electron beam.

  15. Electron correlation and relativistic effects in photoabsorption processes of heavy closed shell atoms: Intermediate shells of Mercury

    NASA Astrophysics Data System (ADS)

    Banerjee, Tanima; Deshmukh, P. C.; Manson, S. T.

    2015-05-01

    Accuracy in the study of the photoionization of heavy atomic systems requires the inclusion of both many-body effects (correlation) and relativistic interactions. The Relative Random Phase Approximation (RRPA) is a powerful theoretical model which includes many important electron corrections, along with relativity, in the calculation of atomic photoionization. Previously, valence photoionization in atomic mercury has been investigated using RRPA. To expand the understanding of the the correlation and relativistic effects further, photoionization of the intermediate subshells of atomic mercury, 4s, 4p, 4d, 4f, 5s and 5d, have been studied at different levels of truncations as a means of pinpointing the specific aspect(s) of correlation that is important in a given case. It has been found that the intermediate subshells are sensitive to the correlation and relativistic effects but not as significantly as in the case of valence shell photoionization. In this work we have systematically investigated the changes caused by relativistic and correlation effects on both dipole (E1) and quadrupole (E2) photoionization parameters for atomic mercury.

  16. Use of Sequential Injection Analysis to construct a Potentiometric Electronic Tongue: Application to the Multidetermination of Heavy Metals

    SciTech Connect

    Mimendia, Aitor; Merkoci, Arben; Valle, Manel del; Legin, Andrey

    2009-05-23

    An automated potentiometric electronic tongue (ET) was developed for the quantitative determination of heavy metal mixtures. The Sequential Injection Analysis (SIA) technique was used in order to automate the obtaining of input data, and the combined response was modeled by means of Artificial Neural Networks (ANN). The sensor array was formed by four sensors: two based on chalcogenide glasses Cd sensor and Cu sensor, and the rest on poly(vinyl chloride) membranes Pb sensor and Zn sensor. The Ion Selective Electrode (ISE) sensors were first characterized with respect to one and two analytes, by means of high-dimensionality calibrations, thanks to the use of the automated flow system; this characterization enabled an interference study of great practical utility. To take profit of the dynamic nature of the sensor's response, the kinetic profile of each sensor was compacted by Fast Fourier Transform (FFT) and the extracted coefficients were used as inputs for the ANN in the multidetermination applications. In order to identify the ANN which provided the best model of the electrode responses, some of the network parameters were optimized. Finally analyses were performed employing synthetic samples and water samples of the river Ebro; obtained results were compared with reference methods.

  17. Use of Sequential Injection Analysis to construct a Potentiometric Electronic Tongue: Application to the Multidetermination of Heavy Metals

    NASA Astrophysics Data System (ADS)

    Mimendia, Aitor; Legin, Andrey; Merkoçi, Arben; del Valle, Manel

    2009-05-01

    An automated potentiometric electronic tongue (ET) was developed for the quantitative determination of heavy metal mixtures. The Sequential Injection Analysis (SIA) technique was used in order to automate the obtaining of input data, and the combined response was modeled by means of Artificial Neural Networks (ANN). The sensor array was formed by four sensors: two based on chalcogenide glasses Cd sensor and Cu sensor, and the rest on poly(vinyl chloride) membranes Pb sensor and Zn sensor. The Ion Selective Electrode (ISE) sensors were first characterized with respect to one and two analytes, by means of high-dimensionality calibrations, thanks to the use of the automated flow system; this characterization enabled an interference study of great practical utility. To take profit of the dynamic nature of the sensor's response, the kinetic profile of each sensor was compacted by Fast Fourier Transform (FFT) and the extracted coefficients were used as inputs for the ANN in the multidetermination applications. In order to identify the ANN which provided the best model of the electrode responses, some of the network parameters were optimized. Finally analyses were performed employing synthetic samples and water samples of the river Ebro; obtained results were compared with reference methods.

  18. Magnetism in the heavy-electron superconductors UPt/sub 3/ and URu/sub 2/Si/sub 2/

    SciTech Connect

    Norman, M.R.; Oguchi, T.; Freeman, A.J.

    1988-12-01

    The nature of magnetism in the heavy-electron superconductors UPt/sub 3/ and URu/sub 2/Si/sub 2/ is investigated by using a spin-orbit generalized variant of local-spin-density (LSD) theory to calculate the self-consistent moment-polarized electronic structure and the dynamic (bare-band) susceptibility. It is shown that the direction of the magnetic moment is predicted correctly. The size of the moment, however, is 0.8..mu../sub B/ in UPt/sub 3/ and 1.2..mu../sub B/ in URu/sub 2/Si/sub 2/, i.e., a factor of 40 larger than experiment. It is noted, however, that the experimental moment of (0.65 +- 0.1)..mu../sub B/ for Th- or Pd-doped UPt/sub 3/ is close to the theoretical value. The static susceptibility, chi(q), is predicted to be weakly dependent on q except for UPt/sub 3/, where a peak is found at q = (..pi../c)(0,0,2): in general agreement with neutron-scattering data at high frequencies. The low-frequency anomalies in the neutron data which lead to magnetic ordering are not seen in the calculated dynamic susceptibility, but can be understood in terms of a moment-moment interaction. An explanation for these conflicting data is offered based on the interaction of itinerant quasiparticle and local-moment degrees of freedom at low temperatures, which leads to a renormalization of the LSD spin-spin response function.

  19. Initial state fluctuations and higher harmonic flow in heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Gale, Charles; Jeon, Sangyong; Schenke, Björn; Tribedy, Prithwish; Venugopalan, Raju

    2013-05-01

    A framework combining Yang-Mills dynamics of the pre-equilibrium glasma with relativistic viscous hydrodynamic evolution of the quark-gluon plasma and hadron gas phases is presented. Event-by-event fluctuations of nucleon positions and color charges are taken into account, leading to negative binomial fluctuations of gluon multiplicities. Experimental anisotropic flow coefficients v2 - v5 of charged hadron distributions in heavy-ion collisions at the Large Hadron Collider are well described. Furthermore, event-by-event distributions of v2,v3andv4 measured by the ATLAS collaboration are reproduced.

  20. Ultrafast electronic relaxation of excited state vitamin B 12 in the gas phase

    NASA Astrophysics Data System (ADS)

    Shafizadeh, Niloufar; Poisson, Lionel; Soep, Benoıˆt

    2008-06-01

    The time evolution of electronically excited vitamin B 12 (cyanocobalamin) has been observed for the first time in the gas phase. It reveals an ultrafast decay to a state corresponding to metal excitation. This decay is interpreted as resulting from a ring to metal electron transfer. This opens the observation of the excited state of other complex biomimetic systems in the gas phase, the key to the characterisation of their complex evolution through excited electronic states.

  1. Formation and nonlinear dynamics of the squeezed state of a helical electron beam with additional deceleration

    NASA Astrophysics Data System (ADS)

    Egorov, E. N.; Koronovskii, A. A.; Kurkin, S. A.; Hramov, A. E.

    2013-11-01

    Results of numerical simulations and analysis of the formation and nonlinear dynamics of the squeezed state of a helical electron beam in a vircator with a magnetron injection gun as an electron source and with additional electron deceleration are presented. The ranges of control parameters where the squeezed state can form in such a system are revealed, and specific features of the system dynamics are analyzed. It is shown that the formation of a squeezed state of a nonrelativistic helical electron beam in a system with electron deceleration is accompanied by low-frequency longitudinal dynamics of the space charge.

  2. Formation and nonlinear dynamics of the squeezed state of a helical electron beam with additional deceleration

    SciTech Connect

    Egorov, E. N. Koronovskii, A. A.; Kurkin, S. A.; Hramov, A. E.

    2013-11-15

    Results of numerical simulations and analysis of the formation and nonlinear dynamics of the squeezed state of a helical electron beam in a vircator with a magnetron injection gun as an electron source and with additional electron deceleration are presented. The ranges of control parameters where the squeezed state can form in such a system are revealed, and specific features of the system dynamics are analyzed. It is shown that the formation of a squeezed state of a nonrelativistic helical electron beam in a system with electron deceleration is accompanied by low-frequency longitudinal dynamics of the space charge.

  3. Stability of Surface State Electrons on Helium Films

    NASA Astrophysics Data System (ADS)

    Leiderer, P.; Scheer, E.; Kono, K.; Lin, J.-J.; Rees, D. G.

    2016-05-01

    Electrons on helium substrates form a model Coulomb system in which the transition from classical electron liquid to Wigner crystal is readily observed. However, attempts to increase the electron density in order to observe the `quantum melting' of the system to a Fermi degenerate gas are hindered by an instability of the helium surface. Here we describe experimental efforts to reach the degenerate regime on thin helium films and microstructured substrates, for which the surface instability is suppressed. We demonstrate that, although the electron densities obtained exceed those for bulk helium substrates, observation of quantum melting remains challenging. We discuss possible solutions to the technical challenges involved.

  4. Modeling of free electronic state density in hydrogenic plasmas based on nearest neighbor approximation

    SciTech Connect

    Nishikawa, Takeshi

    2014-07-15

    Most conventional atomic models in a plasma do not treat the effect of the plasma on the free-electron state density. Using a nearest neighbor approximation, the state densities in hydrogenic plasmas for both bound and free electrons were evaluated and the effect of the plasma on the atomic model (especially for the state density of the free electron) was studied. The model evaluates the electron-state densities using the potential distribution formed by the superposition of the Coulomb potentials of two ions. The potential from one ion perturbs the electronic state density on the other. Using this new model, one can evaluate the free-state density without making any ad-hoc assumptions. The resulting contours of the average ionization degree, given as a function of the plasma temperature and density, are shifted slightly to lower temperatures because of the effect of the increasing free-state density.

  5. Computational simulation and interpretation of the low-lying excited electronic states and electronic spectrum of thioanisole.

    PubMed

    Li, Shaohong L; Xu, Xuefei; Truhlar, Donald G

    2015-08-21

    Three singlet states, namely a closed-shell ground state and two excited states with (1)ππ* and (1)nσ* character, have been suggested to be responsible for the radiationless decay or photochemical reaction of photoexcited thioanisole. The correct interpretation of the electronic spectrum is critical for understanding the character of these low-lying excited states, but the experimental spectrum is yet to be fully interpreted. In the work reported here, we investigated the nature of those three states and a fourth singlet state of thioanisole using electronic structure calculations by multireference perturbation theory, by completely-renormalized equation-of-motion coupled cluster theory with single and double excitations and noniterative inclusion of connected triples (CR-EOM-CCSD(T)), and by linear-response time-dependent density functional theory (TDDFT). We clarified the assignment of the electronic spectrum by simulating it using a normal-mode sampling approach combined with TDDFT in the Tamm-Dancoff approximation (TDA). The understanding of the electronic states and of the accuracy of the electronic structure methods lays the foundation of our future work of constructing potential energy surfaces. PMID:26088195

  6. 78 FR 46686 - Privacy Act of 1974; Treasury/United States Mint .013-United States Mint National Electronic...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-01

    ...In accordance with the requirements of the Privacy Act of 1974, as amended, 5 U.S.C. 552a, the Department of the Treasury (``Treasury'') and the United States Mint proposes to establish a new system of records entitled, ``Treasury/United States Mint .013--United States Mint National Electronic Incident Reporting System of...

  7. Structural evolution and valence electron-state change during ultra thin silicon-oxide growth

    NASA Astrophysics Data System (ADS)

    Shimizu, A.; Abe, S.; Nakayama, H.; Nishino, T.; Iida, S.

    2000-06-01

    We have studied valence electron-state changes of Si during initial oxidation of Si(111) clean surface, HF-treated Si(001) and Si(111) surfaces by Auger valence electron spectroscopy (AVES). The results showed that the valence electron-state changes during initial oxidation were sensitively reflected in Si[2s,2p,V] (V=3s,3p) AVES spectra and that they depended on both initial surface treatment and surface orientation. The local valence electron-states, local density of states in other words, showed the characteristic-structure evolution depending on the initial surface treatment and surface orientation.

  8. The effects of heavy doping on the electronic states in semiconductors

    SciTech Connect

    Sernelius, B.E.

    1987-01-01

    The physics of semiconductors is reviewed. Topics included in the discussion are energy of the dopant system (kinetic energy in a many-valley semiconductor, exchange energy in an ellipsoidal Fermi volume, energy in a polar semiconductor), self energy shifts, band-gap narrowing, and piezo experiments. 31 refs., 27 figs.

  9. Excited electronic states of complex heteroatomic molecules in series and in different aggregation states of matter

    NASA Astrophysics Data System (ADS)

    Obukhov, Alexandr E.

    1995-01-01

    We investigate the spectroscopic and photophysical properties of new series complex molecules, which is capable of fluorescence and some generating light in solvents of various kinds within the wavelength region 308 - 420 nm with a high fluorescence quantum yield (gamma) equals 0.01 - 0.97 and a low threshold pump density Elp(Plp). We worked from the measured lifetimes and to calculate the rate constants for radiative decay (Kfl) and intercombinational conversion, (KST), the cross section for a stimulated emission ((sigma) 31osc), and the characteristic time tlp in solvents of various types and in the vapor. The latter is the limiting rise time of the pump pulse (tlp) at which the generation of electromagnetic radiation is still possible. The cross sections for the induced singlet-singlet ((sigma) 3S*) and triplet-triplet ((sigma) 2T*) absorption in the generation band, required for calculating tlp, were taken from a variety of sources: experimental and for all other complex molecules, we used results calculated by some semiempirical methods SCF MO LKAO the Pariser-Parr-Pople (PPP/CI) and in complete neglect of differential overlap (INDO/S-CI). The results show that the decrease or increase of in the switch from solution to vapor, or as the properties of the solvent change, stems from dynamic separation or overlap of the lasing and induced absorption bands of the S1* yields Sn* and T1 yields Tn transitions. Lasing does not occur in concentrated acids because of the nearly complete overlap of the limiting gain and induced absorption T1 yields Tn transitions (compare it with the behavior of dyes in their chemo absorbed state). Using the density matrix method, we show that the solvent affects the distribution of electron density among the individual atoms and fragments of the complex geteratomic molecule in the ground state, leading to systematic changes in geometry. As a result, there are changes in the distribution of bond lengths in the rings of the azo

  10. Ultrafast electronic state conversion at room temperature utilizing hidden state in cuprate ladder system

    PubMed Central

    Fukaya, R.; Okimoto, Y.; Kunitomo, M.; Onda, K.; Ishikawa, T.; Koshihara, S.; Hashimoto, H.; Ishihara, S.; Isayama, A.; Yui, H.; Sasagawa, T.

    2015-01-01

    Photo-control of material properties on femto- (10−15) and pico- (10−12) second timescales at room temperature has been a long-sought goal of materials science. Here we demonstrate a unique ultrafast conversion between the metallic and insulating state and the emergence of a hidden insulating state by tuning the carrier coherence in a wide temperature range in the two-leg ladder superconductor Sr14-xCaxCu24O41 through femtosecond time-resolved reflection spectroscopy. We also propose a theoretical scenario that can explain the experimental results. The calculations indicate that the holes injected by the ultrashort light reduce the coherence among the inherent hole pairs and result in suppression of conductivity, which is opposite to the conventional photocarrier-doping mechanism. By using trains of ultrashort laser pulses, we successively tune the carrier coherence to within 1 picosecond. Control of hole-pair coherence is shown to be a realistic strategy for tuning the electronic state on ultrafast timescales at room temperature. PMID:26481604

  11. A quantum defect analysis of heavy Rydberg behaviour in the B(u+1Σ) and B″ B ‾ (u+1Σ) states of H2 and the B(u+1Σ) state of D2

    NASA Astrophysics Data System (ADS)

    Lawley, Kenneth P.; Donovan, Robert J.

    2016-08-01

    Heavy Rydberg behaviour in the B(u+1Σ) and B″ B ‾ (u+1Σ) ion-pair states of H2 and the B(u+1Σ) state of D2, is analysed in terms of the absolute quantum defects of the vibronic levels. The influence of the inner repulsive wall of ion-pair potentials on heavy Rydberg behaviour is considered and shown to determine the size of both absolute quantum defects and their energy dependence.

  12. Nonadiabtic electron dynamics in densely quasidegenerate states in highly excited boron cluster

    NASA Astrophysics Data System (ADS)

    Yonehara, Takehiro; Takatsuka, Kazuo

    2016-04-01

    Following the previous study on nonadiabatic reaction dynamics including boron clusters [T. Yonehara and K. Takatsuka, J. Chem. Phys. 137, 22A520 (2012)], we explore deep into highly excited electronic states of the singlet boron cluster (B12) to find the characteristic features of the densely quasi-degenerate electronic state manifold, which undergo very frequent nonadiabatic transitions and thereby intensive electronic state mixing among very many of the relevant states. So much so, isolating the individual adiabatic states and tracking the expected potential energy surfaces both lose the physical sense. This domain of molecular situation is far beyond the realm of the Born-Oppenheimer approximation. To survey such a violent electronic state-mixing, we apply a method of nonadiabatic electron wavepacket dynamics, the semiclassical Ehrenfest method. We have tracked those electron wavepackets and found the electronic state mixing looks like an ultrafast diffusion in the Hilbert space, which results in huge fluctuation. Furthermore, due to such a violent mixing, the quantum phases associated with the electronic states are swiftly randomized, and consequently the coherence among the electronic states are lost quickly. Besides, these highly excited states are mostly of highly poly-radical nature, even in the spin singlet manifold and the number of radicals amounts up to 10 electrons in the sense of unpaired electrons. Thus the electronic states are summarized to be poly-radical and decoherent with huge fluctuation in shorter time scales of vibrational motions. The present numerical study sets a theoretical foundation for unknown molecular properties and chemical reactivity of such densely quasi-degenerate chemical species.

  13. Nonadiabtic electron dynamics in densely quasidegenerate states in highly excited boron cluster.

    PubMed

    Yonehara, Takehiro; Takatsuka, Kazuo

    2016-04-28

    Following the previous study on nonadiabatic reaction dynamics including boron clusters [T. Yonehara and K. Takatsuka, J. Chem. Phys. 137, 22A520 (2012)], we explore deep into highly excited electronic states of the singlet boron cluster (B12) to find the characteristic features of the densely quasi-degenerate electronic state manifold, which undergo very frequent nonadiabatic transitions and thereby intensive electronic state mixing among very many of the relevant states. So much so, isolating the individual adiabatic states and tracking the expected potential energy surfaces both lose the physical sense. This domain of molecular situation is far beyond the realm of the Born-Oppenheimer approximation. To survey such a violent electronic state-mixing, we apply a method of nonadiabatic electron wavepacket dynamics, the semiclassical Ehrenfest method. We have tracked those electron wavepackets and found the electronic state mixing looks like an ultrafast diffusion in the Hilbert space, which results in huge fluctuation. Furthermore, due to such a violent mixing, the quantum phases associated with the electronic states are swiftly randomized, and consequently the coherence among the electronic states are lost quickly. Besides, these highly excited states are mostly of highly poly-radical nature, even in the spin singlet manifold and the number of radicals amounts up to 10 electrons in the sense of unpaired electrons. Thus the electronic states are summarized to be poly-radical and decoherent with huge fluctuation in shorter time scales of vibrational motions. The present numerical study sets a theoretical foundation for unknown molecular properties and chemical reactivity of such densely quasi-degenerate chemical species. PMID:27131547

  14. Serials and New Technology: The State of the "Electronic Journal."

    ERIC Educational Resources Information Center

    Piternick, Anne B.

    1989-01-01

    Reviews reasons why electronic journals have not replaced printed materials, and describes ways in which new technologies such as online searching, full text databases, facsimile transmission, optical disk, and other electronic storage methods are offering alternative methods of access to printed journals. Future technological developments and…

  15. Some Chemical and Electronic Considerations of Solid State Semiconductor Crystals.

    ERIC Educational Resources Information Center

    Hinitz, Herman J.

    1986-01-01

    Describes the trend toward the use of electronic instrumentation to monitor and measure various parameters in chemical reactions. Stresses that a knowledge of the operational relationships involved in such instruments is essential for students beginning in science. Discusses electrostatic charges, semiconductor crystals, electronic conductors,…

  16. Neutron scattering studies of the heavy Fermion superconductors

    NASA Astrophysics Data System (ADS)

    Goldman, A. I.

    Recent neutron scattering measurements of the heavy Fermion superconductors are described. Those materials offer an exciting opportunity for neutron scattering since the f-electrons, which couple directly to magnetic scattering measurements, seem to be the same electrons which form the superconducting state below T sub c. In addition, studies of the magnetic fluctuations in these, and other heavy Fermion systems, by inelastic magnetic neutron scattering can provide information about the nature of the low temperature Fermi liquid character of these novel compounds.

  17. Pulsed-field ionization zero electron kinetic energy spectrum of the ground electronic state of BeOBe+.

    PubMed

    Antonov, Ivan O; Barker, Beau J; Heaven, Michael C

    2011-01-28

    The ground electronic state of BeOBe(+) was probed using the pulsed-field ionization zero electron kinetic energy photoelectron technique. Spectra were rotationally resolved and transitions to the zero-point level, the symmetric stretch fundamental and first two bending vibrational levels were observed. The rotational state symmetry selection rules confirm that the ground electronic state of the cation is (2)Σ(g)(+). Detachment of an electron from the HOMO of neutral BeOBe results in little change in the vibrational or rotational constants, indicating that this orbital is nonbonding in nature. The ionization energy of BeOBe [65480(4) cm(-1)] was refined over previous measurements. Results from recent theoretical calculations for BeOBe(+) (multireference configuration interaction) were found to be in good agreement with the experimental data. PMID:21280724

  18. Pulsed-field ionization zero electron kinetic energy spectrum of the ground electronic state of BeOBe+

    NASA Astrophysics Data System (ADS)

    Antonov, Ivan O.; Barker, Beau J.; Heaven, Michael C.

    2011-01-01

    The ground electronic state of BeOBe+ was probed using the pulsed-field ionization zero electron kinetic energy photoelectron technique. Spectra were rotationally resolved and transitions to the zero-point level, the symmetric stretch fundamental and first two bending vibrational levels were observed. The rotational state symmetry selection rules confirm that the ground electronic state of the cation is 2Σg+. Detachment of an electron from the HOMO of neutral BeOBe results in little change in the vibrational or rotational constants, indicating that this orbital is nonbonding in nature. The ionization energy of BeOBe [65480(4) cm-1] was refined over previous measurements. Results from recent theoretical calculations for BeOBe+ (multireference configuration interaction) were found to be in good agreement with the experimental data.

  19. Fast probe of local electronic states in nanostructures utilizing a single-lead quantum dot

    PubMed Central

    Otsuka, Tomohiro; Amaha, Shinichi; Nakajima, Takashi; Delbecq, Matthieu R.; Yoneda, Jun; Takeda, Kenta; Sugawara, Retsu; Allison, Giles; Ludwig, Arne; Wieck, Andreas D.; Tarucha, Seigo

    2015-01-01

    Transport measurements are powerful tools to probe electronic properties of solid-state materials. To access properties of local electronic states in nanostructures, such as local density of states, electronic distribution and so on, micro-probes utilizing artificial nanostructures have been invented to perform measurements in addition to those with conventional macroscopic electronic reservoirs. Here we demonstrate a new kind of micro-probe: a fast single-lead quantum dot probe, which utilizes a quantum dot coupled only to the target structure through a tunneling barrier and fast charge readout by RF reflectometry. The probe can directly access the local electronic states with wide bandwidth. The probe can also access more electronic states, not just those around the Fermi level, and the operations are robust against bias voltages and temperatures. PMID:26416582

  20. Fast probe of local electronic states in nanostructures utilizing a single-lead quantum dot

    NASA Astrophysics Data System (ADS)

    Otsuka, Tomohiro; Amaha, Shinichi; Nakajima, Takashi; Delbecq, Matthieu R.; Yoneda, Jun; Takeda, Kenta; Sugawara, Retsu; Allison, Giles; Ludwig, Arne; Wieck, Andreas D.; Tarucha, Seigo

    2015-09-01

    Transport measurements are powerful tools to probe electronic properties of solid-state materials. To access properties of local electronic states in nanostructures, such as local density of states, electronic distribution and so on, micro-probes utilizing artificial nanostructures have been invented to perform measurements in addition to those with conventional macroscopic electronic reservoirs. Here we demonstrate a new kind of micro-probe: a fast single-lead quantum dot probe, which utilizes a quantum dot coupled only to the target structure through a tunneling barrier and fast charge readout by RF reflectometry. The probe can directly access the local electronic states with wide bandwidth. The probe can also access more electronic states, not just those around the Fermi level, and the operations are robust against bias voltages and temperatures.

  1. Hydrodynamic simulations of relativistic heavy-ion collisions with different lattice quantum chromodynamics calculations of the equation of state

    NASA Astrophysics Data System (ADS)

    Moreland, J. Scott; Soltz, Ron A.

    2016-04-01

    Hydrodynamic calculations of ultrarelativistic heavy-ion collisions are performed using the iebe-vishnu 2+1-dimensional code with fluctuating initial conditions and three different parametrizations of the lattice QCD equations of state: continuum extrapolations for stout and HISQ/tree actions, as well as the s95p-v1 parametrization based upon calculations using the p4 action. All parametrizations are matched to a hadron resonance gas equation of state at T =155 MeV, at which point the calculations are continued using the urqmd hadronic cascade. Simulations of √{sN N}=200 GeV Au+Au collisions in three centrality classes are used to quantify anisotropic flow developed in the hydrodynamic phase of the collision as well as particle spectra and pion Hanbury-Brown-Twiss (HBT) radii after hadronic rescattering, which are compared with experimental data. Experimental observables for the stout and HISQ/tree equations of state are observed to differ by less than a few percent for all observables, while the s95p-v1 equation of state generates spectra and flow coefficients which differ by ˜10 -20 % . Calculations in which the HISQ/tree equation of state is sampled from the published error distribution are also observed to differ by less than a few percent.

  2. Evolution of solid-state induction modulators for a heavy-ion recirculator

    SciTech Connect

    Kirbie, H.; Hanks, R.; Hawkins, S.

    1996-06-01

    The Laser Program at Lawrence Livermore National Laboratory (LLNL) pioneered the use of large-scale glass lasers to heat inertial-fusion targets. Today, that same exploratory spirit applies to the latest laser-fusion effort-the National Ignition Facility (NIF). The NIF has the potential to pave the way to commercial power extraction from inertial fusion, as long as the generating system is affordable and it operates repetitively. These fundamental issues of cost and repetition rate have stimulated a search for alternative fusion-target drivers to replace large, single-shot lasers. The authors are developing an ion approach whereby converging beams of heavy ions act as the driver. Like lasers, the ions impart their energy to the target and produce fusion temperatures. The difference lies in the ability of particle accelerators to generate repetitive bursts of ions with a higher efficiency at a lower cost.

  3. The Low-Lying Electronic States of LiB

    NASA Technical Reports Server (NTRS)

    Ricca, Alessandra; Bauschlicher, Charles W., Jr.; Langhoff, Stephen R. (Technical Monitor)

    1995-01-01

    The spectroscopic constants for the triplet and singlet states of LiB below about 30 000/ cm are determined using an internally contracted multireference configuration interaction approach in conjunction with [6s 5p 3d 2f] atomic natural orbital basis sets. The ground state is (sup 3)Pi as found in previous work. No excited triplet states are found to be ideal for characterizing the ground state; the (1)(sup 3)Sigma(sup -) state has a transition energy that is too small for many experimental approaches and the (2)(sup 3)Pi and (3)(sup 3)Pi states have bond lengths that are significantly longer than the ground state, resulting in transition intensities that are spread out over many vibrational levels of the ground state.

  4. Elliptic azimuthal anisotropy of heavy-flavour decay electrons in Pb-Pb collisions at √(S{sub NN}) = 2.76 TeV measured with ALICE

    SciTech Connect

    ALICE Collaboration, Denise Moreira de Godoy for the

    2014-11-11

    In this paper, we present the ALICE results on the elliptic azimuthal anisotropy of heavy-flavour decay electrons in 20-40% central Pb-Pb collisions at √(S{sub NN}) = 2.76 TeV. Heavy quarks are produced in the early stages of the collision and they interact with the hot and dense color-deconfined medium created in heavy-ion collisions at high energies, the Quark-Gluon Plasma (QGP). Measurements of the elliptic azimuthal anisotropy of heavy-flavour decay electrons in non-central collisions can be used to investigate the degree of thermalization and energy loss of heavy quarks within the QGP. Theoretical predictions of heavy-quark transport in the medium are compared with the measurement.

  5. Low charge state heavy ion production with sub-nanosecond laser

    NASA Astrophysics Data System (ADS)

    Kanesue, T.; Kumaki, M.; Ikeda, S.; Okamura, M.

    2016-02-01

    We have investigated laser ablation plasma of various species using nanosecond and sub-nanosecond lasers for both high and low charge state ion productions. We found that with sub-nanosecond laser, the generated plasma has a long tail which has low charge state ions determined by an electrostatic ion analyzer even under the laser irradiation condition for highly charged ion production. This can be caused by insufficient laser absorption in plasma plume. This property might be suitable for low charge state ion production. We used a nanosecond laser and a sub-nanosecond laser for low charge state ion production to investigate the difference of generated plasma using the Zirconium target.

  6. Electron impact spectroscopy. [for atom and molecule quantum state investigation

    NASA Technical Reports Server (NTRS)

    Trajmar, S.

    1980-01-01

    The concepts of electron impact spectroscopy are discussed, comparing the electron spectroscopy techniques with those of the optical spectroscopy. The main advantage of the electron spectroscopy is to be found in the elimination of optical selection rules in excitation processes and the ability to scan the spectrum from the infrared to the X-ray region. The range of the method is indicated through a review of several examples, including electron impact excitation of Ba and rotational excitation of H2. The sensitivity of the method is demonstrated by vibrational excitation spectrum of N2. It is shown that the application of the method to the inner-shell excitation allows to obtain information about molecular species which are not commonly available, while spectroscopy of negative ions yields information about their energy and symmetry properties. However, the techniques are still under development and more data are expected to become available in the coming years.

  7. Broadband 2D Electronic Spectroscopy Reveals Coupling Between Dark 1Bu- State of Carotenoid and Qx State of Bacteriochlorophyll

    NASA Astrophysics Data System (ADS)

    Ostroumov, Evgeny E.; Jumper, Chanelle C.; Mulvaney, Rachel M.; Cogdell, Richard J.; Scholes, Gregory D.

    2013-03-01

    The study of LH2 protein of purple bacteria by broadband 2D electronic spectroscopy is presented. The dark 1Bu- carotenoid state is directly observed in 2D spectra and its role in carotenoid-bacteriochlorophyll interaction is discussed.

  8. State of the Art in Electronic Dosemeters for Neutrons

    SciTech Connect

    Luszik-Bhadra, Marlies

    2011-05-05

    The paper presents an overview of electronic personal dosemeters for neutrons in mixed neutron/photon fields. The energy response of commercially available electronic dosemeters in quasi-monoenergetic neutron fields and their performance in working places is discussed. The response curves are extended to high-energy neutrons up to 100 MeV, new prototype dosemeters are described and discussed especially for use at high-energy accelerators and in space.

  9. Excited State Electronic Properties of Sodium Iodide and Cesium Iodide

    SciTech Connect

    Campbell, Luke W.; Gao, Fei

    2013-05-01

    We compute from first principles the dielectric function, loss function, lifetime and scattering rate of quasiparticles due to electronic losses, and secondary particle spectrum due to plasmon decay in two scintillating alkali halides, sodium iodide and cesium iodide. Particular emphasis is placed on quasiparticles within several multiples of the band gap from the band edges. A theory for the decay spectra of plasmons and other electronic excitations in crystals is presented. Applications to Monte Carlo radiation transport codes are discussed.

  10. State of the Art in Electronic Dosemeters for Neutrons

    NASA Astrophysics Data System (ADS)

    Luszik-Bhadra, Marlies

    2011-05-01

    The paper presents an overview of electronic personal dosemeters for neutrons in mixed neutron/photon fields. The energy response of commercially available electronic dosemeters in quasi-monoenergetic neutron fields and their performance in working places is discussed. The response curves are extended to high-energy neutrons up to 100 MeV, new prototype dosemeters are described and discussed especially for use at high-energy accelerators and in space.

  11. Cost-effective production of Bacillus thuringiensis biopesticides by solid-state fermentation using wastewater sludge: effects of heavy metals.

    PubMed

    Zhuang, Li; Zhou, Shungui; Wang, Yueqiang; Liu, Zhi; Xu, Rongxian

    2011-04-01

    This study demonstrated the feasibility to produce Bacillus thuringiensis subsp. kurstaki (Btk) based biopesticides using wastewater sludge as raw materials under solid-state fermentation (SSF). More than 10(10) CFU/g viable cells of Btk were obtained using sludge or its mixture with agricultural wastes. This study well considered the effect of heavy metals on Btk growth and their changes of chemical speciation caused by SSF. The IC(50) (concentration causing 50% inhibition in total cell biomass) for Pb(II), Cu(II), Cd(II) and Cr(III) on Btk were determined to be 227, 82, 15 and 263 mg/L, respectively. Exposure to 150 mg/L of Cu(II) severely reduced the amount and size of toxin crystals, which decreased the endotoxin synthesis and entomotoxicity potency of Btk cells. Using Tessier's sequential extraction procedure, the exchangeable heavy metals in sludge were shown to be transformed into residual fractions after SSF, and thus significantly reduced their bioavailability and potential environmental risks. PMID:21295967

  12. Mobilities of heavy metals in surface waters: A field study of Mineral Branch, Tri-State Mining District

    SciTech Connect

    Piechowski, M.F.; Carroll, S.A. . Dept. of Geological Sciences)

    1992-01-01

    A field study of the mobilities of heavy metals was done in the Tri-State Mining District near Joplin, Missouri. The processing of ores left many large tailings piles in this region which are predominantly chert, but contain minor amounts of carbonate and sulfide minerals. The residual sphalerite, galena, marcasite, and pyrite readily dissolve when exposed to surface waters, increasing the acidity and concentrations of Pb, Zn, and Cd in the streams of the region. Mineral Branch is a local stream that originates in and flows through a tailings field. Water and sediment (bed and suspended load) samples were collected and analyzed by ICP and XRD methods in order to determine trace and major element concentrations and mineral compositions, respectively. The solids are primarily chert and carbonates, with small amounts of crystalline and amorphous iron hydroxides and oxyhydroxides. Over the two mile study area, pH increases steadily downstream. As the pH rises, the dissolved heavy metal concentrations fall, some by an order of magnitude or more. It was also found that over 99% of the Pb, Zn,and Cd in the system is presents in the solids. Precipitation of carbonates or hydroxides does not adequately explain the concentration changes seen in the system. The adsorption of the metal species onto the carbonates and iron oxyhydroxides of the stream sediments as a function of pH is an additional controlling factor in the Mineral Branch.

  13. Pt{sub 3}Au and PtAu clusters: Electronic states and potential energy surfaces

    SciTech Connect

    Dai, D.; Balasubramanian, K.

    1994-03-15

    We carried out complete active space multiconfiguration self-consistent-field calculations followed by multireference singles+doubles configuration interaction with the Davidson correction which included up to 3.55 million configurations employing relativistic effective core potentials on Pt{sub 3}+Au and PtAu clusters. Four low-lying electronic states were identified for Pt{sub 3}+Au. The {sup 2}{ital A}{sub 2} electronic state ({ital C}{sub 3{ital v}}) was found to be the ground state of Pt{sub 3}Au. Spin--orbit effects were found to be significant. We also computed six low-lying electronic states of PtAu and four low-lying electronic states of PtAu{sup +}. The 5/2 ({sup 2}{Delta}) and 0{sup +}({sup 1}{Sigma}{sup +}) states were found to be the ground states of PtAu and PtAu{sup +}, respectively.

  14. 77 FR 65379 - Cross-Media Electronic Reporting: Authorized Program Revision Approval, State of Wyoming

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-26

    ... 13, 2005, the final Cross-Media Electronic Reporting Rule (CROMERR) was published in the Federal Register (70 FR 59848) and codified as part 3 of title 40 of the CFR. CROMERR establishes electronic... AGENCY Cross-Media Electronic Reporting: Authorized Program Revision Approval, State of Wyoming...

  15. Measurement of electrons from heavy-flavour decays in p-Pb collisions at √(S{sub NN}) = 5.02 TeV with ALICE

    SciTech Connect

    ALICE collaboration, Cristiane Jahnke for the

    2014-11-11

    Electrons from the decay of hadrons containing charm or beauty quarks have been measured in p-Pb collisions at √(S{sub NN}) = 5.02 TeV with ALICE. Electrons from heavy-flavour hadron decays were identified using the Time Projection Chamber and the Electromagnetic Calorimeter of ALICE. The nuclear modification factor R{sub pPb} was calculated using a pp reference obtained from a perturbative QCD-based √(s)-extrapolation of the cross section measured at 7 TeV and from a FONLL prediction.

  16. 75 FR 983 - Cross-Media Electronic Reporting Rule State Approved Program Revision/Modification Approvals...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-07

    ... Rule (CROMERR) was published in the Federal Register (70 FR 59848) and codified as Part 3 of ] title 40... AGENCY Cross-Media Electronic Reporting Rule State Approved Program Revision/Modification Approvals... announces EPA's approval, under regulations for Cross-Media Electronic Reporting, of the State...

  17. The In-Gap Electronic State Spectrum of Methylammonium Lead Iodide Single-Crystal Perovskites.

    PubMed

    Adinolfi, Valerio; Yuan, Mingjian; Comin, Riccardo; Thibau, Emmanuel S; Shi, Dong; Saidaminov, Makhsud I; Kanjanaboos, Pongsakorn; Kopilovic, Damir; Hoogland, Sjoerd; Lu, Zheng-Hong; Bakr, Osman M; Sargent, Edward H

    2016-05-01

    The density of trap states within the bandgap of methylammonium lead iodide single crystals is investigated. Defect states close to both the conduction and valence bands are probed. Additionally, a comprehensive electronic characterization of crystals is carried out, including measurements of the electron and hole mobility, and the energy landscape (band diagram) at the surface. PMID:26932458

  18. Structures and electronic states of halogen-terminated graphene nano-flakes

    NASA Astrophysics Data System (ADS)

    Tachikawa, Hiroto; Iyama, Tetsuji

    2015-12-01

    Halogen-functionalized graphenes are utilized as electronic devices and energy materials. In the present paper, the effects of halogen-termination of graphene edge on the structures and electronic states of graphene flakes have been investigated by means of density functional theory (DFT) method. It was found that the ionization potential (Ip) and electron affinity of graphene (EA) are blue-shifted by the halogen termination, while the excitation energy is red-shifted. The drastic change showed a possibility as electronic devices such as field-effect transistors. The change of electronic states caused by the halogen termination of graphene edge was discussed on the basis of the theoretical results.

  19. Low-lying electronic excited states of pentacene oligomers: a comparative electronic structure study in the context of singlet fission.

    PubMed

    Coto, Pedro B; Sharifzadeh, Sahar; Neaton, Jeffrey B; Thoss, Michael

    2015-01-13

    The lowest-lying electronic excited states of pentacene and its oligomers are investigated using accurate multireference wave function methods (CASPT2/CASSCF) and the many-body Greens's function approach (GW/BSE). The results obtained for dimers and trimers of different geometry reveal a complex electronic structure, which includes locally excited, charge transfer, and multiexciton states. For singlets of single-excitation character, both approaches yield excitation energies that are in good overall quantitative agreement. While the multiexciton states are located relatively high in energy in all systems investigated, charge transfer states exist in close proximity to the lowest-lying absorbing states. The implications of the results for the mechanisms of singlet fission in pentacene are discussed. PMID:26574213

  20. Relativistic heavy ion research. [Dept. of Physics and Astronomy, Wayne State Univ. , Detroit, Michigan

    SciTech Connect

    Not Available

    1992-01-01

    Experimental work is reported on the following topics: transverse energy production in 10.7-GeV/c/u Au on Au collisions; first results on delta ray production and charged particle multiplicities with the Au beam at 10.7 GeV/c/A; preliminary studies on the feasibility of flow measurement with the E814 participant calorimeter; preliminary results from the E877 telescope; and low-p[sub t] baryon distribution in Si+Al, Pb collisions at the AGS. Then the status of the Hadronic Calorimeter project of AGS Experiment E864 (ECOS--Exotic Composite Object Spectrometer) is reviewed. Next, the same is done for work of the STAR RHIC collaboration (Silicon Vertex Tracker (SVT) project evolution and development in FY92, SVT software results from 1992, SVT instrumentation, FY93 SVT pion test beam). The instrumentation section deals with the design and installation of a target rapidity telescope for BNL experiment 814/877 and a repair scheme for the E814/E877 participant calorimeter. Finally, the theory part addresses bosonic kinetics: thermalization of mesons and the pion p[sub perpendicular] spectrum in ultrarelativistic heavy-ion collisions and non-equilibrium properties of hadronic mixtures.

  1. Electron propagator calculations on the ground and excited states of C60(-).

    PubMed

    Zakrzewski, V G; Dolgounitcheva, O; Ortiz, J V

    2014-09-01

    Electron propagator calculations in two approximations—the third-order algebraic, diagrammatic construction and the outer valence Green’s function (OVGF)—have been performed on the vertical electron affinities of C60 and the vertical electron detachment energies of several states of C60(–) with a variety of basis sets. These calculations predict bound (2)T1u and (2)T1g anions, but fail to produce (2)T2u or (2)Hg anionic states that are more stable than ground-state C60. The electron affinity for the (2)Ag state is close to zero, but no definitive result on its sign has been obtained. This state may be a resonance or marginally bound anion. The OVGF prediction for the vertical electron detachment energy of (2)T1u C60(–), 2.63 eV, is in excellent agreement with recent anion photoelectron spectra. PMID:24813804

  2. Ionization states of heavy elements observed in the 1974 May 14-15 anomalous solar particle event

    NASA Technical Reports Server (NTRS)

    Ma Sung, L. S.; Gloeckler, G.; Fan, C. Y.; Hovestadt, D.

    1981-01-01

    The charge states of heavy ions accelerated in the (He-3)-Fe-rich solar particle event of May 14-15, 1974 have been determined by the use of using data from the University of Maryland/Max-Planck-Institut experiment on IMP 8. In addition to Fe(+11,12), it is found that both O(+5) and Fe(+16,17,18) are also present, suggesting variations in coronal temperatures over a range from approximately 400,000 to 5,000,000 K. The presence of O(+5) and Fe(+16-18) may be explained by a resonant plasma heating mechanism proposed by Fisk (1978) to account for the enhancements of He-3 and Fe.

  3. Electron-impact excitation of the low-lying electronic states of HCN

    NASA Technical Reports Server (NTRS)

    Chutjian, A.; Tanaka, H.; Srivastava, S. K.; Wicke, B. G.

    1977-01-01

    The first study of the low-energy electron-impact excitation of low-lying electronic transitions in the HCN molecule is reported. Measurements were made at incident electron energies of 11.6 and 21.6 eV in the energy-loss range of 3-10 eV, and at scattering angles of 20-130 deg. Inelastic scattering spectra were placed on the absolute cross-section scale by determining first the ratio of inelastic-to-elastic scattering cross sections, and then separately measuring the absolute elastic scattering cross section. Several new electronic transitions are observed which are intrinsically overlapped in the molecule itself. Assignments of these electronic transitions are suggested. These assignments are based on present spectroscopic and cross-sections measurements, high-energy electron scattering spectra, optical absorption spectra, and ab initio molecular orbital calculations.

  4. Gain in the non-steady-state free-electron laser

    SciTech Connect

    Wu, D.; Min, Y.

    1995-09-01

    The non-steady-state self-consistent equation in the linear regime of the free-electron laser (FEL) and the low gain formulas in the non-steady-state FEL are derived in this paper. It is found that due to slippage the nonuniformity effect in the longitudinal distribution of the electron beam density is dominant in the influence of the electron pulse length on the gain of the FEL. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  5. On the excitation energy of deep-hole states in medium-heavy-mass spherical nuclei

    NASA Astrophysics Data System (ADS)

    Kolomiytsev, G. V.; Igashov, S. Yu.; Urin, M. H.

    2016-01-01

    Within the particle-hole dispersive optical model it is shown that the spreading effect determines a significant part of the anomalously large excitation energy of deep-hole states in the 90Zr and 208Pb parent nuclei.

  6. Low charge state heavy ion production with sub-nanosecond laser.

    PubMed

    Kanesue, T; Kumaki, M; Ikeda, S; Okamura, M

    2016-02-01

    We have investigated laser ablation plasma of various species using nanosecond and sub-nanosecond lasers for both high and low charge state ion productions. We found that with sub-nanosecond laser, the generated plasma has a long tail which has low charge state ions determined by an electrostatic ion analyzer even under the laser irradiation condition for highly charged ion production. This can be caused by insufficient laser absorption in plasma plume. This property might be suitable for low charge state ion production. We used a nanosecond laser and a sub-nanosecond laser for low charge state ion production to investigate the difference of generated plasma using the Zirconium target. PMID:26931977

  7. Present State of Electron Backscatter Diffraction and Prospective Developments

    SciTech Connect

    Schwarzer, R A; Field, D P; Adams, B L; Kumar, M; Schwartz, A J

    2008-10-24

    Electron backscatter diffraction (EBSD), when employed as an additional characterization technique to a scanning electron microscope (SEM), enables individual grain orientations, local texture, point-to-point orientation correlations, and phase identification and distributions to be determined routinely on the surfaces of bulk polycrystals. The application has experienced rapid acceptance in metallurgical, materials, and geophysical laboratories within the past decade (Schwartz et al. 2000) due to the wide availability of SEMs, the ease of sample preparation from the bulk, the high speed of data acquisition, and the access to complementary information about the microstructure on a submicron scale. From the same specimen area, surface structure and morphology of the microstructure are characterized in great detail by the relief and orientation contrast in secondary and backscatter electron images, element distributions are accessed by energy dispersive spectroscopy (EDS), wavelength dispersive spectroscopy (WDS), or cathodoluminescence analysis, and the orientations of single grains and phases can now be determined, as a complement, by EBSD.

  8. Heavy-metal pollution and its state in algae in Kakehashi river and Godani river at the foot of Ogoya mine, Ishikawa Prefecture.

    PubMed

    Nakanishi, Yoshiaki; Sumita, Michiaki; Yumita, Kaoru; Yamada, Takashi; Honjo, Takaharu

    2004-01-01

    Alga as Achnanthes minutissima among diatoms is a widely adaptable taxon on the state of an aquatic environment. In this study, it was found that diatom had a specific tolerance to heavy metals (Cu, Zn, Pb, and Cd etc.) in river water samples, because the diatom assemblage consisted of almost only Achnanthes minutissima in Kakehashi river and Godani river, which were polluted with waste water from Ogoya copper mine. The relationship between the concentrations of heavy metals (Cu, Zn, Pb and Cd) in river water and the attached substances (algae and silt etc.) and the relative abundances of diatom taxa were investigated in detail. The results indicated that the higher is the concentration of heavy metals in the river environment, the higher is only the relative abundances of Achnanthes minutissima. Thus, the taxon can be used as a bioindicator of heavy metal pollution. The relative rates of toxic chemical forms of copper in algae were 61 - 92% in the attached substances and 49-70% in the sediment on the river bed, respectively. Therefore, it was found that diatom as Achnanthes minutissima had a tolerance to heavy metals in river water, being able to live in such an environment. Since the water treated with calcium hydroxide from the deposition reservoir of Ogoya mine enters in Godani river, the river is polluted by heavy metals (Cu, Zn, Pb and Cd etc.). From the viewpoint of both biological and chemical analyses, Godani river is still polluted with heavy metals, because their concentrations in the river samples were very high. On the other hand, in Kakehashi river, the concentrations of heavy metals were very low and the distributions of some diatoms appeared in an unpolluted Nishimata river were observed. Therefore, Kakehashi river seems to be considerably recovered from heavy-metal pollution after closing the Ogoya mine. PMID:14753260

  9. Recent results in relativistic heavy ion collisions: from 'a new state of matter' to 'the perfect fluid'

    NASA Astrophysics Data System (ADS)

    Tannenbaum, M. J.

    2006-07-01

    Experimental physics with relativistic heavy ions dates from 1992 when a beam of 197Au of energy greater than 10 A GeV/c first became available at the Alternating Gradient Synchrotron at Brookhaven National Laboratory (BNL) soon followed in 1994 by a 208Pb beam of 158A GeV/c at the Super Proton Synchrotron at CERN (European Center for Nuclear Research). Previous pioneering measurements at the Berkeley Bevalac (Gutbrod et al 1989 Rep. Prog. Phys. 52 1267-132) in the late 1970s and early 1980s were at much lower bombarding energies (<~1A GeV/c) where nuclear breakup rather than particle production is the dominant inelastic process in A+A collisions. More recently, starting in 2000, the relativistic heavy ion collider at BNL has produced head-on collisions of two 100 A GeV beams of fully stripped Au ions, corresponding to nucleon-nucleon centre-of-mass (cm) energy, \\sqrt{s_NN}=200\\,GeV , total cm energy 200 A GeV. The objective of this research program is to produce nuclear matter with extreme density and temperature, possibly resulting in a state of matter where the quarks and gluons normally confined inside individual nucleons (r < 1 fm) are free to act over distances an order of magnitude larger. Progress from the period 1992 to the present will be reviewed, with reference to previous results from light ion and proton-proton collisions where appropriate. Emphasis will be placed on the measurements which formed the basis for the announcements by the two major laboratories: 'A new state of matter', by CERN on Febraury 10 2000 and 'The perfect fluid' by BNL on April 19 2005.

  10. Entropy, fidelity, and double orthogonality for resonance states in two-electron quantum dots

    SciTech Connect

    Pont, Federico M.; Osenda, Omar; Serra, Pablo; Toloza, Julio H.

    2010-04-15

    Resonance states of a two-electron quantum dots are studied using a variational expansion with both real basis-set functions and complex scaling methods. The two-electron entanglement (linear entropy) is calculated as a function of the electron repulsion at both sides of the critical value, where the ground (bound) state becomes a resonance (unbound) state. The linear entropy and fidelity and double orthogonality functions are compared as methods for the determination of the real part of the energy of a resonance. The complex linear entropy of a resonance state is introduced using complex scaling formalism.

  11. Generation of tunable entangled states of two electrons and their characterization without entanglement witness

    NASA Astrophysics Data System (ADS)

    Chandra, N.; Ghosh, R.

    2004-12-01

    In this Rapid Communication, we show that a simple process of two-step double ionization taking place in an atom A , following the absorption of a single photon, produces a spin-entangled state of two electrons. The degree of entanglement of this state can be tuned to the desired value by selecting appropriate total spin quantum numbers of the electronic states of each of the three atomic species (i.e., A, A+ , A2+ ) participating in the process in Russell-Saunders coupling. These entangled states are readily characterized by measuring only energies of two emitted electrons, without requiring the entanglement witness, or any other such protocol.

  12. Does electron-transfer theory explain large rate differences in singlet and triplet excited state electron-transfer reactions?

    SciTech Connect

    Zusman, L.D.; Kurnikov, I.V.; Beratan, D.N.

    1995-12-31

    Gray and coworkers have shown that intramolecular electron-transfer rates from singlet and triplet excited states in iridium(spacer)pyridinium complexes can be vastly different (>5 orders of magnitude). We have analyzed the possible sources of these differences, including effects that may arise from reorganization energies, free energies, and tunneling matrix elements. When distance dependent reorganization energies and energy dependent tunneling matrix elements are included, a systematic framework emerges to describe these electron-transfer reactions.

  13. Heavy-ion Fractionation in the Impulsive Solar Energetic Particle Event of 2002 August 20: Elements, Isotopes, and Inferred Charge States

    NASA Astrophysics Data System (ADS)

    Wiedenbeck, M. E.; Cohen, C. M. S.; Leske, R. A.; Mewaldt, R. A.; Cummings, A. C.; Stone, E. C.; von Rosenvinge, T. T.

    2010-08-01

    Measurements of heavy-ion elemental and isotopic composition in the energy range ~12-60 MeV nucleon-1 are reported from the Advanced Composition Explorer/Solar Isotope Spectrometer (ACE/SIS) instrument for the solar energetic particle (SEP) event of 2002 August 20. We investigate fractionation in this particularly intense impulsive event by examining the enhancements of elemental and isotopic abundance ratios relative to corresponding values in the solar wind. The elemental enhancement pattern is similar to those in other impulsive events detected by ACE/SIS and in compilations of average impulsive-event composition. For individual elements, the abundance of a heavy isotope (mass M 2) is enhanced relative to that of a lighter isotope (M 1) by a factor ~(M 1/M 2)α with α ~= -15. Previous studies have reported elemental abundance enhancements organized as a power law in Q/M, the ratio of estimated ionic charge to mass in the material being fractionated. We consider the possibility that a fractionation law of this form could be responsible for the isotopic fractionation as a power law in the mass ratio and then explore the implications it would have for the ionic charge states in the source material. Assuming that carbon is fully stripped (Q C = 6), we infer mean values of the ionic charge during the fractionation process, QZ , for a variety of elements with atomic numbers 7 <= Z <= 28. We find that Q Fe ~= 21-22, comparable to the highest observed values that have been reported at lower energies in impulsive SEP events from direct measurements near 1 AU. The inferred charge states as a function of Z are characterized by several step increases in the number of attached electrons, Z - QZ . We discuss how this step structure, together with the known masses of the elements, might account for a variety of features in the observed pattern of elemental abundance enhancements. We also briefly consider alternative fractionation laws and the relationship between the charge

  14. HEAVY-ION FRACTIONATION IN THE IMPULSIVE SOLAR ENERGETIC PARTICLE EVENT OF 2002 AUGUST 20: ELEMENTS, ISOTOPES, AND INFERRED CHARGE STATES

    SciTech Connect

    Wiedenbeck, M. E.; Cohen, C. M. S.; Leske, R. A.; Mewaldt, R. A.; Cummings, A. C.; Stone, E. C.; Von Rosenvinge, T. T.

    2010-08-20

    Measurements of heavy-ion elemental and isotopic composition in the energy range {approx}12-60 MeV nucleon{sup -1} are reported from the Advanced Composition Explorer/Solar Isotope Spectrometer (ACE/SIS) instrument for the solar energetic particle (SEP) event of 2002 August 20. We investigate fractionation in this particularly intense impulsive event by examining the enhancements of elemental and isotopic abundance ratios relative to corresponding values in the solar wind. The elemental enhancement pattern is similar to those in other impulsive events detected by ACE/SIS and in compilations of average impulsive-event composition. For individual elements, the abundance of a heavy isotope (mass M {sub 2}) is enhanced relative to that of a lighter isotope (M{sub 1}) by a factor {approx}(M {sub 1}/M {sub 2}){sup {alpha}} with {alpha} {approx_equal} -15. Previous studies have reported elemental abundance enhancements organized as a power law in Q/M, the ratio of estimated ionic charge to mass in the material being fractionated. We consider the possibility that a fractionation law of this form could be responsible for the isotopic fractionation as a power law in the mass ratio and then explore the implications it would have for the ionic charge states in the source material. Assuming that carbon is fully stripped (Q{sub C} = 6), we infer mean values of the ionic charge during the fractionation process, Q{sub Z} , for a variety of elements with atomic numbers 7 {<=} Z {<=} 28. We find that Q{sub Fe} {approx_equal} 21-22, comparable to the highest observed values that have been reported at lower energies in impulsive SEP events from direct measurements near 1 AU. The inferred charge states as a function of Z are characterized by several step increases in the number of attached electrons, Z - Q{sub Z} . We discuss how this step structure, together with the known masses of the elements, might account for a variety of features in the observed pattern of elemental abundance

  15. Fission and cluster decay of the {sup 76}Sr nucleus in the ground state and formed in heavy-ion reactions

    SciTech Connect

    Gupta, Raj K.; Sharma, Manoj K.; Singh, Sarbjit; Nouicer, Rachid; Beck, Christian

    1997-12-01

    Calculations for fission and cluster decay of {sup 76}Sr are presented for this nucleus to be in its ground state or formed as an excited compound system in heavy-ion reactions. The predicted mass distribution, for the dynamical collective mass transfer process assumed for fission of {sup 76}Sr, is clearly asymmetric, favoring {alpha} nuclei. Cluster decay is studied within a preformed cluster model, both for ground-state to ground-state decays and from excited compound system to the ground state(s) or excited states(s) of the fragments. {copyright} {ital 1997} {ital The American Physical Society}

  16. Relativistic electrons spin states and spin light in dense neutrino fluxes

    NASA Astrophysics Data System (ADS)

    Balantsev, Ilya; Studenikin, Alexander

    2016-05-01

    Relativistic electrons can produce electromagnetic radiation in moving background composed of neutrinos, that is the “spin light of electron in neutrino flux” (SLev ) [1, 2]. In this paper we further specify the electron quantum states in moving neutrino background by introdusing the electron spin operator that enables one to define the electron wave function in an exact and close form. This justifies our previous studies of SLev in dense neutrino fluxes and derivations of the electron energy spectrum, the radiation rate and power, and also the emitted photon energy. We argue that the SLev can have important consequences in different astrophysical settings.

  17. Excited states of a hydrated electron and aqueous chloride by computer simulation

    NASA Astrophysics Data System (ADS)

    Borgis, Daniel; Staib, Arnulf

    1994-12-01

    Results of adiabatic molecular dynamics simulations for a hydrated electron and the aqueous chloride anion are reported. A novel technical feature is the efficient representation of solute electronic wavefunctions in terms of floating spherical Gaussian orbitals. The simulations account for the coupling of the excess electron to the solvent electronic polarization in an explicit and self-consistent fashion. The computed electronic ground state absorption spectrum for e(-)/H2O and the charge-transfer-to-solvent spectra for Cl(-)/H2O are analyzed. The energetic aspects of the models and the short time solute electronic dynamics are discussed.

  18. Determination and Comparison of Carbonyl Stretching Frequency of a Ketone in Its Ground State and the First Electronic Excited State

    ERIC Educational Resources Information Center

    Bandyopadhyay, Subhajit; Roy, Saswata

    2014-01-01

    This paper describes an inexpensive experiment to determine the carbonyl stretching frequency of an organic keto compound in its ground state and first electronic excited state. The experiment is simple to execute, clarifies some of the fundamental concepts of spectroscopy, and is appropriate for a basic spectroscopy laboratory course. The…

  19. Current state, sources, and potential risk of heavy metals in sediments of Three Gorges Reservoir, China.

    PubMed

    Bing, Haijian; Zhou, Jun; Wu, Yanhong; Wang, Xiaoxiao; Sun, Hongyang; Li, Rui

    2016-07-01

    Heavy metal (HM) contamination in sediments of Three Gorges Reservoir (TGR) is a particularly important issue for the safety of water quality due to the potential threats of metal toxicity to local and downstream human health. Surface sediments from riparian and submerged areas in the entire TGR mainstream were collected in 2014 to investigate the spatial distribution of HMs (Cd, Cu, Pb, and Zn), identify their possible sources, and assess their potential risk by multiple indices and metal fraction. Results showed that the concentrations of HMs in the sediments increased after the TGR operation, but were lower than those in other Chinese rivers of developed areas. The acid-soluble Cd accounted for more than 50% of total Cd in the sediments, whereas that of other HMs was very low. The Cd concentrations in the riparian sediments increased towards the dam; however, other metals in the riparian sediments and all HMs in the submerged sediments did not show any regular variation trend spatially. The stocks of HMs were significantly higher in the submerged sediments than in the riparian sediments. The high accumulation of HMs in the riparian sediments emerged between Fuling and Fengjie, and those in the submerged sediments existed in the near dam areas. Grain size and Fe/Mn oxides controlled the mobility and transfer of HMs in the sediments. Human activity in the catchment including industrial and agricultural production, shipping industry, mining, etc., increased inputs of HMs in the sediments, and altered their spatial distribution patterns. The sediments were moderately to highly contaminated by Cd, and slightly contaminated by other HMs. The results indicate the current priority of Cd contamination in the TGR, and will conduce to ecological protection in the TGR region. PMID:27131806

  20. Magnetic dipole moment measurements of picosecond states in even and odd heavy nuclei

    SciTech Connect

    Ballon, D.J.

    1985-01-01

    The perturbed angular correlation transient field technique is used to measure the precession of nuclear magnetic moments of low lying excited states in isotopes of silver, neodymium, samarium, and gadolinium. The precession measurements are used to explore three main areas of study. First, from the measurements made on /sup 150/Sm transversing gadolinium targets, the temperature dependence of the transient hyperfine field is deduced at /sup 150/Sm nuclei traveling at 2 < v/v/sub 0/ < 4. These are compared with similar measurements made using iron targets. Second, the deduced values of the g-factors of the 2/sub 1/ + states in even neodymium, samarium and gadolinium isotopes are discussed in connection with a possible proton shell closure at Z = 64. Third, the deduced values of the g-factors of the 3/2/sub 1/- and 5/2/sub 1/- states of /sup 107,109/Ag are compared to various theoretical predictions in order to explore any simple relationships that may exist between these states and the first 2/sub 1/+ states of neighboring even-even nuclei.

  1. Control of the electronic ground state on an electron-transfer copper site by second-sphere perturbations.

    PubMed

    Morgada, Marcos N; Abriata, Luciano A; Zitare, Ulises; Alvarez-Paggi, Damian; Murgida, Daniel H; Vila, Alejandro J

    2014-06-10

    The Cu(A) center is a dinuclear copper site that serves as an optimized hub for long-range electron transfer in heme-copper terminal oxidases. Its electronic structure can be described in terms of a σ(u)* ground-state wavefunction with an alternative, less populated ground state of π(u) symmetry, which is thermally accessible. It is now shown that second-sphere mutations in the Cu(A) containing subunit of Thermus thermophilus ba3 oxidase perturb the electronic structure, which leads to a substantial increase in the population of the π(u) state, as shown by different spectroscopic methods. This perturbation does not affect the redox potential of the metal site, and despite an increase in the reorganization energy, it is not detrimental to the electron-transfer kinetics. The mutations were achieved by replacing the loops that are involved in protein-protein interactions with cytochrome c, suggesting that transient protein binding could also elicit ground-state switching in the oxidase, which enables alternative electron-transfer pathways. PMID:24777732

  2. Heavy fermion bound states for diphoton excess at 750 GeV — collider and cosmological constraints

    NASA Astrophysics Data System (ADS)

    Han, Chengcheng; Ichikawa, Koji; Matsumoto, Shigeki; Nojiri, Mihoko M.; Takeuchi, Michihisa

    2016-04-01

    A colored heavy particle with sufficiently small width may form non-relativistic bound states when they are produced at the large hadron collider (LHC), and they can annihilate into a diphoton final state. The invariant mass of the diphoton would be around twice of the colored particle mass. In this paper, we study if such bound state can be responsible for the 750 GeV diphoton excess reported by ATLAS and CMS. We found that the best-fit signal cross section is obtained for the SU(2) L singlet colored fermion X with Y X = 4 /3. Having such an exotic hypercharge, the particle is expected to decay through some higher dimensional operators, consistent with the small width assumption. The decay of X may involve a stable particle χ, if both X and χ are odd under some conserved Z 2 symmetry. In that case, the particle X suffers from the constraints of jets + missing E T searches by ATLAS and CMS at 8 TeV and 13 TeV. We found that such a scenario still survives if the mass difference between X and χ is above ˜ 30 GeV for m X ˜ 375 GeV. Even assuming pair annihilation of χ is small, the relic density of χ is small enough if the mass difference between X and χ is smaller than ˜ 40 GeV.

  3. Clustering of Color sources and the Equation of State in Heavy Ion Collisions at RHIC and LHC Energies

    NASA Astrophysics Data System (ADS)

    Scharenberg, R. P.

    2012-11-01

    The initial temperature Ti, energy density ɛi, and formation time τi of the initial state of the QGP formed in the heavy ion collisions at RHIC and LHC energies are determined using the data driven Color String Percolation Model (CSPM). Multiparticle production by interacting strings stretched between projectile and target form a spanning cluster at the percolation threshold. The relativistic kinetic theory relation for η/s is evaluated as a function of T and the mean free path (λmfp) using data and CSPM. η/s(Ti, λmfp) describes the transition from a strongly interacting QGP at T/Tc ~ 1 to a weakly coupled QGP at T/Tc >= 6. We find that the reciprocal of η/s is equal to the trace anomaly Δ = ɛ - 3P/T4 which also describes the transition. We couple this initial state of the QGP to a ID Bjorken expansion to determine the sound velocity c2s of the QGP for 0.85 <= T/Tc <= 3. The bulk thermodynamic quantities and the equation of state are in excellent agreement with LQCD results.

  4. Electronic states in epitaxial graphene fabricated on silicon carbide

    SciTech Connect

    Davydov, S. Yu.

    2011-08-15

    An analytical expression for the density of states of a graphene monolayer interacting with a silicon carbide surface (epitaxial graphene) is derived. The density of states of silicon carbide is described within the Haldane-Anderson model. It is shown that the graphene-substrate interaction results in a narrow gap of {approx}0.01-0.06 eV in the density of states of graphene. The graphene atom charge is estimated; it is shown that the charge transfer from the substrate is {approx}10{sup -3}-10{sup -2}e per graphene atom.

  5. The Low-Lying Electronic States of YCu

    NASA Technical Reports Server (NTRS)

    Ricca, Alessandra; Bauschlicher, Charles W., Jr.; Langhoff, Stephen R. (Technical Monitor)

    1995-01-01

    The spectroscopic constants for the singlet and triplet states of YCu below about 15 000 per centimeter are determined using an internally contracted multireference configuration-interaction approach. These calculations are calibrated by studies of fewer states using higher levels of correlation treatment and/or larger basis sets. The computed T(sub e) values and radiative lifetimes are in reasonable agreement with experiment. The calculations confirm the previous experimental assignment for all but one state, where theory helps resolve between two possible assignments.

  6. A selection rule for the directions of electronic fluxes during unimolecular pericyclic reactions in the electronic ground state

    NASA Astrophysics Data System (ADS)

    Manz, Jörn; Yamamoto, Kentaro

    2012-05-01

    Unimolecular pericyclic reactions in a non-degenerate electronic ground state proceed under the constraint of zero electronic angular momentum. This restriction engenders a selection rule on the directions of electronic fluxes. Accordingly, clockwise or counter-clockwise fluxes are 'forbidden', whereas pincer-like fluxes (which consist of concerted clockwise and counter-clockwise fluxes) are 'allowed'. The selection rule is illustrated for three reactions: the degenerate Cope rearrangement of hexadiene, hydrogen transfer in malonaldehyde, and double proton transfer in the formic acid dimer.

  7. Fine structure of alpha decay to rotational states of heavy nuclei

    SciTech Connect

    Wang, Y. Z.; Dong, J. M.; Peng, B. B.; Zhang, H. F.

    2010-06-15

    To gain a better insight into alpha-decay fine structure, we calculate the relative intensities of alpha decay to 2{sup +} and 4{sup +} rotational states in the framework of the generalized liquid drop model (GLDM) and improved Royer's formula. The calculated relative intensities of alpha decay to 2{sup +} states are in good agreement with the experimental data. For the relative intensities of alpha decay to 4{sup +} states, a good agreement with experimental data is achieved for Th and U isotopes. The formula we obtain is useful for the analysis of experimental data of alpha-decay fine structure. In addition, some predicted relative intensities which are still not measured are provided for future experiments.

  8. Electronic states and potential energy surfaces of rhodium carbide (RhC)

    NASA Astrophysics Data System (ADS)

    Tan, Hang; Liao, Muzhen; Balasubramanian, K.

    1997-12-01

    Potential energy curves and spectroscopic constants of 23 electronic states of the rhodium carbide (RhC) have been studied using the complete-active-space multi-configuration self-consistent field (CASMCSCF) followed by first-order configuration interaction (FOCI) calculations. Multi-reference singles + doubles configuration interaction (MRSDCI) were used to determine the properties of low-lying electronic states. The nature of chemical bond formation in different states is discussed in terms of their wave function and Mulliken populations.

  9. Azimuthal correlations of electrons from heavy-flavor decay with hadrons in p+p and Au+Au collisions at {radical}(s{sub NN})=200 GeV

    SciTech Connect

    Adare, A.; Bickley, A. A.; Ellinghaus, F.; Glenn, A.; Kinney, E.; Kiriluk, K.; Linden Levy, L. A.; Nagle, J. L.; Rosen, C. A.; Seele, J.; Wysocki, M.; Afanasiev, S.; Isupov, A.; Litvinenko, A.; Malakhov, A.; Peresedov, V.; Rukoyatkin, P.; Zolin, L.; Aidala, C.; Datta, A.

    2011-04-15

    Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled p+p collisions. These measurements indicate that charm and bottom quarks interact with the hot dense matter produced in heavy-ion collisions much more than expected. Here we extend these studies to two-particle correlations where one particle is an electron from the decay of a heavy-flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interactions between heavy quarks and the matter, such as whether the modification of the away-side-jet shape seen in hadron-hadron correlations is present when the trigger particle is from heavy-meson decay and whether the overall level of away-side-jet suppression is consistent. We statistically subtract correlations of electrons arising from background sources from the inclusive electron-hadron correlations and obtain two-particle azimuthal correlations at {radical}(s{sub NN})=200 GeV between electrons from heavy-flavor decay with charged hadrons in p+p and also first results in Au+Au collisions. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to p+p collisions.

  10. A DMC study on FePc electronic state

    NASA Astrophysics Data System (ADS)

    Ichibha, Tom; Hongo, Kenta; Maezono, Ryo

    We performed fixed-node DMC calculations on an isolated FePc [Iron(II) Phthalocyanine] using CASSCF nodal surfaces, getting its ground state, 3A2 g [dz22dxz, yz 2dxy2 ]. Virial ratios for each state are achieved to be within 0.042% around 2.0. Recent studies are proposing a mixed state with 3Eg (b) and 3B2 g as the ground state, while past ab-initio calculations are predicting 3A2 g or 3Eg (a) , giving still controversial arguments even within isolated/no-LS coupling model. Under D4 h ligand field parameter space, (10Dq , Dt, Ds), the state, 3A2 g , is reported to be possible as a ground state, while it is not when we restrict the space into 2-dim sub-space corresponding to more specified symmetry as in FePc with plane square alignment of neighboring N to Fe ('superposition model'). Our optimized geometry also satisfies the same symmetry, and hence appears to be contradicting to the ligand theory.

  11. Electronic state dependence of heterogeneous electron transfer: injection from the S1 and S2 state of phlorin into TiO2

    PubMed Central

    Nieto-Pescador, Jesus; Abraham, Baxter; Pistner, Allen J.; Rosenthal, Joel

    2016-01-01

    Ultrafast time-resolved measurements were performed on a novel pentafluorophenyl substituted 5,5-dimethyl phlorin derivative in solution and when attached to TiO2 colloidal films. The complex excited state dynamics of this porphyrinoid after S1 and S2 excitation was compared at different wavelengths and can be assigned to several subsequent relaxation mechanisms. The difference between excited state dynamics in the free molecule and when attached to an electron accepting electrode was measured. For both cases the dynamics was compared after excitation to the S1 and the S2 state. For the free molecule in solution an intermediate relaxation step was identified and assigned to a buckling motion of the tetrapyrrole ring. On the electrode, heterogeneous electron transfer (HET) times from both states were very similar and around 50 fs. Surprisingly, the large difference in the density of acceptor states that are resonant with the respective donor level of the molecule does not significantly influence HET dynamics. This result indicates that HET proceeds into intermediate transition states that are different from steady state surface states obtained from experiments or computations. The density of states (DOS) of these transient acceptor states appears not to be directly related to the corresponding surface or bulk DOS. PMID:25721314

  12. Strongly separated pairs of core electrons in computed ground states of small molecules

    PubMed Central

    Gottlieb, Alex D.; Weishäupl, Rada M.

    2013-01-01

    We have performed full configuration interaction computations of the ground states of the molecules Be, BeH2, Li, LiH, B, and BH and verified that the core electrons constitute “separated electron pairs.” These separated pairs of core electrons have nontrivial structure; the core pair does not simply occupy a single spatial orbital. Our method of establishing the presence of separated electron pairs is direct and conclusive. We do not fit a separated pair model; we work with the wavefunctions of interest directly. To establish that a given group of spin–orbitals contains a quasi-separated pair, we verify by direct computation that the quantum state of the electrons that occupy those spin–orbitals is nearly a pure 2-electron state. PMID:23459686

  13. Charge-state dependence of kinetic electron emission induced by slow ions in metals

    SciTech Connect

    Juaristi, J.I.; Dubus, A.; Roesler, M.

    2003-07-01

    A calculation is performed in order to analyze the charge-state dependence of the kinetic electron emission induced by slow ions in metals. All stages of the emission process are included: the excitation of the electrons, the neutralization of the projectile during its passage through the solid, and the transport of the excited electrons from where they are created to the surface. It is shown that the number of excited electrons depends strongly on the ion charge state. Nevertheless, due to the fast neutralization of the ions within the escape depth of the excited electrons, no significant initial charge-state dependence is expected in the kinetic electron yield. This result is consistent with available experimental data.

  14. Fast coherent manipulation of three-electron states in a double quantum dot

    NASA Astrophysics Data System (ADS)

    Shi, Zhan; Simmons, C. B.; Ward, Daniel R.; Prance, J. R.; Wu, Xian; Koh, Teck Seng; Gamble, John King; Savage, D. E.; Lagally, M. G.; Friesen, Mark; Coppersmith, S. N.; Eriksson, M. A.

    2014-01-01

    An important goal in the manipulation of quantum systems is the achievement of many coherent oscillations within the characteristic dephasing time T2*. Most manipulations of electron spins in quantum dots have focused on the construction and control of two-state quantum systems, or qubits, in which each quantum dot is occupied by a single electron. Here we perform quantum manipulations on a system with three electrons per double quantum dot. We demonstrate that tailored pulse sequences can be used to induce coherent rotations between three-electron quantum states. Certain pulse sequences yield coherent oscillations fast enough that more than 100 oscillations are visible within a T2* time. The minimum oscillation frequency we observe is faster than 5 GHz. The presence of the third electron enables very fast rotations to all possible states, in contrast to the case when only two electrons are used, in which some rotations are slow.

  15. Properties near magnetic instability of heavy-electron compounds Ce3M4Sn13 and La3M4Sn13, with M=Co, Rh and Ru

    NASA Astrophysics Data System (ADS)

    Ślebarski, Andrzej

    2015-02-01

    In this review, we report the thermodynamic, magnetic and electronic transport properties of the skutterudite-related Ce3M4Sn13 and La3M4Sn13 intermetallic compounds with M = Co, Rh and Ru, which display a variety of behaviours. Ce3M4Sn13 exhibit a large increase in C/T with a maximum value of about 4 JK-2mol-1Ce due to strong electron and short-range magnetic correlations. These compounds show a crossover from a magnetically correlated heavy-fermion state to a single impurity state in applied magnetic fields. In order to study the proximity of Ce3Co4Sn13 to the possible magnetic quantum critical point (QCP), we investigated the system of Ce3-xLaxCo4Sn13 alloys. We found the critical concentration ?, which separates the magnetically correlated state (?) from a single impurity state (?), however the low-T C(T)/T and the magnetic susceptibility behaviours are not characteristic of the QCP. With increasing of the magnetic field, resistivity follows power law behaviour for the samples ?, with n strongly field dependent. The ?-anomaly is discussed on the base of spin-fluctuation theory of Moriya and Takimoto. Specific heat data show that La3M4Sn13 are typical BCS superconductors, however, La3Rh4Sn13 and La3Ru4Sn13 exhibit a second superconducting phase, characteristic of inhomogeneous superconductors.

  16. Polarized electron correlations near auto-ionizing states of zinc atoms

    NASA Astrophysics Data System (ADS)

    Williams, James; Pravica, Luka; Samarin, Sergey

    2015-09-01

    Multi-electron metal atoms find new applications in diverse structures with spin and momentum-dependent properties having significance in determining material functionalities. Electron correlations effects are determined from scattering kinematics of spin-polarized electrons exciting zinc atoms near autoionizing states up to 16 eV. Previous studies of the 4p 3 , 1P1 , 4 d,5 d,6d3D1 , 2 , 3 and 4 d,5d1D1 excited states observed photon decay intensities and scattered electron energies and angles in the energy region of the 3d94s24 p autoionizing states up to 12 eV. Strong electron correlations and active roles of 3 d electrons were evident. Our observations of the 53S excited state for electron energies up to 16 eV show dominant 3 d core-excited negative-ion resonances and strong Post-Collision Interaction (PCI). For low energies of scattered and ejected electrons, after near-threshold excitation of the 3d94s24 p autoionizing states, a large transfer of orbital angular momentum is evident. Results include angular differential elastic scattering and excitation functions, ``integrated'' Stokes polarization parameters and spin up/down asymmetries indicating spin-orbit interaction and electron exchange effects. School of Physics

  17. Meissner Effect of Dirac Electrons in Superconducting State Due to Inter-Band Effect

    NASA Astrophysics Data System (ADS)

    Mizoguchi, Tomonari; Ogata, Masao

    2015-08-01

    Dirac electrons in solids show characteristic physical properties due to their linear dispersion relation and two-band nature. Although the transport phenomena of Dirac electrons in a normal state have intensively been studied, the transport phenomena in a superconducting state have not been fully understood. In particular, it is not clear whether Dirac electrons in a superconducting state show Meissner effect (ME), since a diamagnetic term of a current operator is absent as a result of the linear dispersion. We investigate the ME of three dimensional massive Dirac electrons in a superconducting state on the basis of Kubo formula, and clarify that Meissner kernel becomes finite by use of the inter-band contribution. This mechanism of the ME for Dirac electrons is completely different from that for the electrons in usual metals. Our result shows that the Meissner kernel remains finite even when the superconducting gap vanishes. This is an unavoidable problem in the Dirac electron system as reported in the previous works. Thus, we use a prescription in which we subtract the normal state contribution. In order to justify this prescription, we develop a specific model where the Meissner kernel is obtained by the prescription. We also derive the result for the electron gas by taking the non-relativistic limit of Dirac Hamiltonian, and clarify that the diamagnetic term of the Meissner kernel can be regarded as the inter-band contribution between electrons and positrons in terms of the Dirac model.

  18. Electron impact excitation of autoionising states of krypton

    NASA Technical Reports Server (NTRS)

    Srivastava, S. K.; Trajmar, S.

    1978-01-01

    Energy-loss spectra of krypton in the region between 21 and 29 eV have been obtained at electron impact energies of 30, 60 and 100 eV. For each energy, the angular distribution of intensities has been measured at 5, 10 and 15 deg scattering angles. Assignments of spectral features found in this region are suggested and a comparison is made with previous measurements.

  19. Determination of state-to-state electron-impact rate coefficients between Ar excited states: a review of combined diagnostic experiments in afterglow plasmas

    NASA Astrophysics Data System (ADS)

    Zhu, Xi-Ming; Cheng, Zhi-Wen; Carbone, Emile; Pu, Yi-Kang; Czarnetzki, Uwe

    2016-08-01

    Electron-impact excitation processes play an important role in low-temperature plasma physics. Cross section and rate coefficient data for electron-impact processes from the ground state to excited states or between two excited states are required for both diagnostics and modeling works. However, the collisional processes between excited states are much less investigated than the ones involving the ground state due to various experimental challenges. Recently, a method for determining electron excitation rate coefficients between Ar excited states in afterglow plasmas was successfully implemented and further developed to obtain large sets of collisional data. This method combines diagnostics for electron temperature, electron density, and excited species densities and kinetic modeling of excited species, from which the electron excitation rate coefficients from one of the 1s states to the other 1s states or to one of 2p or 3p states are determined (states are in Paschen’s notation). This paper reviews the above method—namely the combined diagnostics and modeling in afterglow plasmas. The results from other important approaches, including electron-beam measurement of cross sections, laser pump-probe technique for measuring rate coefficients, and theoretical calculations by R-matrix and distorted-wave models are also discussed. From a comparative study of these results, a fitted mathematical expression of excitation rate coefficients is obtained for the electron temperature range of 1–5 eV, which can be used for the collisional-radiative modeling of low-temperature Ar plasmas. At last, we report the limitations in the present dataset and give some suggestions for future work in this area.

  20. Exotic Self-trapped States of an Electron in Superfluid Helium

    NASA Astrophysics Data System (ADS)

    Elser, Veit

    2015-09-01

    We explore the possibility that the fast and exotic negative ions in superfluid helium are electrons bound to quantized vortex structures, the simplest being a ring. In the states we consider, the electron energy is only slightly below the conduction band minimum of bulk helium. To support our proposal, we present two calculations. In the first, we show that the electron pressure on the vortex core is insufficient to cavitate the helium and form an electron bubble. In the second, we estimate the equilibrium radius of the vortex ring that would bind an electron and find it is much smaller than the electron bubble, about 7 Å. The many exotic ions reported in experiments might be bound states of an electron with more complex vortex structures.