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Sample records for heavy electron state

  1. Electronic and structural ground state of heavy alkali metals at high pressure

    DOE PAGES

    Fabbris, G.; Lim, J.; Veiga, L. S. I.; ...

    2015-02-17

    Here, alkali metals display unexpected properties at high pressure, including emergence of low symmetry crystal structures, that appear to occur due to enhanced electronic correlations among the otherwise nearly-free conduction electrons. We investigate the high pressure electronic and structural ground state of K, Rb, and Cs using x-ray absorption spectroscopy and x-ray diffraction measurements together with ab initio theoretical calculations. The sequence of phase transitions under pressure observed at low temperature is similar in all three heavy alkalis except for the absence of the oC84 phase in Cs. Both the experimental and theoretical results point to pressure-enhanced localization of themore » valence electrons characterized by pseudo-gap formation near the Fermi level and strong spd hybridization. Although the crystal structures predicted to host magnetic order in K are not observed, the localization process appears to drive these alkalis closer to a strongly correlated electron state.« less

  2. Electronic and structural ground state of heavy alkali metals at high pressure

    SciTech Connect

    Fabbris, G.; Lim, J.; Veiga, L. S. I.; Haskel, D.; Schilling, J. S.

    2015-02-17

    Here, alkali metals display unexpected properties at high pressure, including emergence of low symmetry crystal structures, that appear to occur due to enhanced electronic correlations among the otherwise nearly-free conduction electrons. We investigate the high pressure electronic and structural ground state of K, Rb, and Cs using x-ray absorption spectroscopy and x-ray diffraction measurements together with ab initio theoretical calculations. The sequence of phase transitions under pressure observed at low temperature is similar in all three heavy alkalis except for the absence of the oC84 phase in Cs. Both the experimental and theoretical results point to pressure-enhanced localization of the valence electrons characterized by pseudo-gap formation near the Fermi level and strong spd hybridization. Although the crystal structures predicted to host magnetic order in K are not observed, the localization process appears to drive these alkalis closer to a strongly correlated electron state.

  3. 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.

  4. 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

  5. Spin-Orbit Coupling and Novel Electronic States at the Interfaces of Heavy Fermion Materials

    DTIC Science & Technology

    2016-02-22

    Reviewed Conference Proceeding publications (other than abstracts): 6.00 --“Local Perspective on Non-Fermi Liquid, Quantum Criticality, and Bad Metals ...New Mexico, Nov. 18-19, 2013. --“Quantum Phase Transitions in Heavy Fermion Metals and Kondo Insulators”, Conference on Quantum Criticality...Frustration and Emergent Phases in Heavy Fermion Metals ”, International Conference on Strongly Correlated Electron SCES-2013, Tokyo, Japan, Aug. 5-9, 2013

  6. Exit charge state dependence of convoy electron production in heavy-ion solid collisions

    SciTech Connect

    Huelskoetter, H.P.; Burgdoerfer, J.; Sellin, I.A.

    1986-01-01

    The dependence of the yield of convoy electrons emitted near the forward direction in collisions involving fast ions and thin solid targets on the emergent projectile charge state is presented and described in terms of primary electron loss events in the solid. The data include a large array of projectiles, projectile energies and charge states, as well as targets ranging in thickness from the non-equilibrium well into the equilibrium thickness region. The description presented is consistent with other experimental and theoretical results indicating that the convoy electron production is closely linked to the ELC process observed in binary ion-atom collisions, with the dominant contribution to the convoy yield stemming from excited states of the projectiles. 22 refs., 3 figs.

  7. 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.

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

    DOE PAGES

    Friedemann, S.; Chang, H.; Gamża, M. B.; ...

    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

    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

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

    SciTech Connect

    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 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. 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.

  11. 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.

  12. Surface-Electronic-State-Modulated, Single-Crystalline (001) TiO2 Nanosheets for Sensitive Electrochemical Sensing of Heavy-Metal Ions.

    PubMed

    Zhou, Wen-Yi; Liu, Jin-Yun; Song, Jie-Yao; Li, Jin-Jin; Liu, Jin-Huai; Huang, Xing-Jiu

    2017-03-21

    Intrinsically low conductivity and poor reactivity restrict many semiconductors from electrochemical detection. Usually, metal- and carbon-based modifications of semiconductors are necessary, making them complex, expensive, and unstable. Here, for the first time, we present a surface-electronic-state-modulation-based concept applied to semiconductors. This concept enables pure semiconductors to be directly available for ultrasensitive electrochemical detection of heavy-metal ions without any modifications. As an example, a defective single-crystalline (001) TiO2 nanosheet exhibits high electrochemical performance toward Hg(II), including a sensitivity of 270.83 μA μM(-1) cm(-2) and a detection limit of 0.017 μM, which is lower than the safety standard (0.03 μM) of drinking water established by the World Health Organization (WHO). It has been confirmed that the surface oxygen vacancy adsorbs an O2 molecule while the Ti(3+) donates an electron, forming the O2(•-) species that facilitate adsorption of Hg(II) and serve as active sites for electron transfer. These findings not only extend the electrochemical sensing applications of pure semiconductors but also stimulate new opportunities for investigating atom-level electrochemical behaviors of semiconductors by surface electronic-state modulation.

  13. 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.

  14. Emergence of superconductivity in heavy-electron materials.

    PubMed

    Yang, Yi-feng; Pines, David

    2014-12-23

    Although the pairing glue for the attractive quasiparticle interaction responsible for unconventional superconductivity in heavy-electron materials has been identified as the spin fluctuations that arise from their proximity to a magnetic quantum critical point, there has been no model to describe their superconducting transition at temperature Tc that is comparable to that found by Bardeen, Cooper, and Schrieffer (BCS) for conventional superconductors, where phonons provide the pairing glue. Here we propose such a model: a phenomenological BCS-like expression for Tc in heavy-electron materials that is based on a simple model for the effective range and strength of the spin-fluctuation-induced quasiparticle interaction and reflects the unusual properties of the heavy-electron normal state from which superconductivity emerges. We show that it provides a quantitative understanding of the pressure-induced variation of Tc in the "hydrogen atoms" of unconventional superconductivity, CeCoIn5 and CeRhIn5, predicts scaling behavior and a dome-like structure for Tc in all heavy-electron quantum critical superconductors, provides unexpected connections between members of this family, and quantifies their variations in Tc with a single parameter.

  15. Emergence of superconductivity in heavy-electron materials

    PubMed Central

    Yang, Yi-feng; Pines, David

    2014-01-01

    Although the pairing glue for the attractive quasiparticle interaction responsible for unconventional superconductivity in heavy-electron materials has been identified as the spin fluctuations that arise from their proximity to a magnetic quantum critical point, there has been no model to describe their superconducting transition at temperature Tc that is comparable to that found by Bardeen, Cooper, and Schrieffer (BCS) for conventional superconductors, where phonons provide the pairing glue. Here we propose such a model: a phenomenological BCS-like expression for Tc in heavy-electron materials that is based on a simple model for the effective range and strength of the spin-fluctuation-induced quasiparticle interaction and reflects the unusual properties of the heavy-electron normal state from which superconductivity emerges. We show that it provides a quantitative understanding of the pressure-induced variation of Tc in the “hydrogen atoms” of unconventional superconductivity, CeCoIn5 and CeRhIn5, predicts scaling behavior and a dome-like structure for Tc in all heavy-electron quantum critical superconductors, provides unexpected connections between members of this family, and quantifies their variations in Tc with a single parameter. PMID:25489102

  16. Electronic states of WH

    NASA Astrophysics Data System (ADS)

    Ma, Zhongxin; Balasubramanian, K.

    1991-07-01

    Spectroscopic constants and potential energy curves of 15 electronic states of WH are obtained using the complete-active-space multi-configuration self-consistent field (CAS MCSCF) followed by full second-order configuration-interaction (SOCI) calculations. The spin-orbit effects are introduced using the relativistic-configuration-interaction (RCI) method. Our computations confirm the assignment of the observed emission spectrum at 6800 Å but yield different vibrational frequencies for the two observed states.

  17. 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.

  18. Convoy electron production in heavy-ion-solid collisions

    SciTech Connect

    Sellin, I.A.; Breinig, M.; Brandt, W.; Laubert, R.

    1981-01-01

    The properties of the sharp v vector/sub e/ approx. = v vector cusps observed in the velocity spectrum of convoy electrons (v vector/sub e/) ejected in heavy ion-solid collisions in the ion velocity range (v vector) 6 to 18 au are compared to the properties of analogous cusps observed in binary electron capture to the continuum (ECC) and electron loss to the continuum (ELC) collisions in gases. Apart from a skew toward v vector/sub e/ > v vector, the v-independent convoy distributions observed are very similar to those for ELC and the cusp widths are the same in both cases. While the shape of convoy peaks is approximately independent of projectile Z, v, and of target material, yields in polycrystalline targets (C, Al, Ag, Au) exhibit a strong dependence on Z and v. Coincidence experiments in which convoy electrons are allocated according to emergent ion charge-state q/sub e/ show a surprising independence of q/sub e/, mirroring the unweighted statistical emergent charge-state fraction. Coincidence experiments of O/sup 6 +/ /sup 7 +/ /sup 8 +/ ions traversing < 110 > and < 100 > channels in Au show a strong yield suppression and a dependence of yield on the channel chosen. Interpretation of these observations, comparisons to convoy production studies using protons, and a discussion of remaining puzzles is given. The history of ECC, ELC, and wake-riding models of convoy electron production is also reviewed.

  19. 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.

  20. Review of metastable states in heavy nuclei

    DOE PAGES

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

    2016-05-31

    Here, 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.

  1. Staining of Tissue Sections for Electron Microscopy with Heavy Metals

    PubMed Central

    Watson, Michael L.

    1958-01-01

    Heavy metals may be incorporated from solution into tissue sections for electron microscopy. The resulting increase in density of the tissue provides greatly enhanced contrast with minimal distortion. Relative densities of various structures are found to depend on the heavy metal ions present and on the conditions of staining. Certain hitherto unobserved details are revealed and some sort of specificity exists, although the factors involved are not yet understood. PMID:13563554

  2. 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].

  3. 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

  4. 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.

  5. New experiments on few-electron very heavy atoms

    SciTech Connect

    Gould, H.

    1985-07-01

    New experiments, to test quantum electrodynamics (QED) in strong Coulomb fields and to study atomic collisions at ultrarelativistic energies, are proposed. A 0.1% measurement of the 2/sup 2/P/sub 1/2/-2/sup 2/S/sub 1/2/ splitting in lithium like uranium (Z=92) and the 2/sup 3/P/sub 0/ - 2/sup 3/S/sub 1/ splitting in heliumlike uranium is proposed as a sub 1% test of the Lamb shift in a strong Coulomb field. Measurements of the hyperfine splitting of hydrogenlike thallium (Z=81) and the g/sub j/ factor of the ground state of hydrogenlike uranium are propsed as a test of the QED contribution to the magnetic moment of an electron bound in a strong Coulomb field. Measurements of capture cross sections for ultra relativistic very heavy nuclei are proposed to look for the capture of electrons from pair production. 40 refs., 7 figs., 2 tabs.

  6. 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.

  7. Modeling Electron-Cloud Effects in Heavy-Ion Accelerators

    SciTech Connect

    Cohen, R H; Friedman, A; Lund, S M; Molvik, A W; Lee, E P; Azevedo, T; Vay, J; Stoltz, P; Veitzer, S

    2004-09-21

    Stray electrons can arise in positive-ion 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 summarize results from several studies undertaken in conjunction with an effort to develop a self-consistent modeling capability: (1) Calculation of the electron cloud produced by electron desorption from computed beam-ion loss, which illustrates the importance of retaining ion reflection at the walls; (2) Simulation of the effect of specified electron cloud distributions on ion beam dynamics; and (3) analysis of an instability associated with a resonance between the beam-envelope ''breathing'' mode and the electron perturbation. We also report first results from a long-timestep algorithm for electron dynamics, which holds promise for efficient simultaneous solution of electron and ion dynamics. One conclusion from study (2) is that heavy-ion beams are surprisingly robust to electron clouds, compared to a priori expectations.

  8. Searches for Heavy Quark States at ATLAS

    NASA Astrophysics Data System (ADS)

    Cheng, Hok-Chuen Tom; ATLAS Collaboration

    2016-11-01

    This talk highlights the latest results of heavy quark searches from the ATLAS collaboration, mainly on resonance searches and vector-like quarks (VLQs) searches. Searches for it resonances using lepton-plus-jets events in proton-proton collisions at center-of-mass energy of 8 and 13 TeV are presented. Limits are set for BSM particles such as topcolor-assisted technicolor Z' TC , Kaluza-Klein (K-K) gluons gKK and K-K excitations of graviton GKK in the Randall-Sundrum model of extra dimensions. VLQs arise naturally in many models such as Little Higgs and Composite Higgs and typically couple preferably to the third generation SM quarks and weak bosons. Limits are set for vector-like bottom (B) and top (T) quarks decay to lepton-plus-jets final states via Hb+X and Ht+X channels in two analyses using 8 and 13 TeV datasets from ATLAS.

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

    NASA Astrophysics Data System (ADS)

    Şengül, M. Y.; Güçlü, M. C.; Fritzsche, S.

    2009-10-01

    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.

  10. Electronic stopping power for heavy ions in hot targets

    NASA Astrophysics Data System (ADS)

    Wang, You-Nian; Ma, Teng-Cai; Gong, Ye

    1993-03-01

    An investigation on the electronic stopping power and the effective charge for a heavy ion in a hot target is made using linear-response dielectric theory. The charge distribution of the electrons bound to a projectile is determined by the Brandt-Kitagawa (BK) model [Phys. Rev. B 25, 3631 (1982)]. Some analytical expressions of the electronic stopping power and the effective charge are obtained in the limits of the low and high velocities, respectively. The theoretical results are compared with the experimental data for high-velocity ions.

  11. Search for bound-state electron+positron pair decay

    NASA Astrophysics Data System (ADS)

    Bosch, F.; Hagmann, S.; Hillenbrand, P.-M.; Lane, G. J.; Litvinov, Yu. A.; Reed, M. W.; Sanjari, M. S.; Stöhlker, Th.; Torilov, S. Yu.; Tu, X. L.; Walke, P. M.

    2016-09-01

    The heavy ion storage rings coupled to in-flight radioactive-ion beam facilities, namely the ability to produce and store for extended periods of time radioactive nuclides in high atomic charge states, for the searchof yet unobserved decay mode - bound-state electron-positron pair decay.

  12. Silt heavy-mineral distributions off the Southeastern United States

    USGS Publications Warehouse

    Poppe, L.J.; Commeau, J.A.

    1996-01-01

    Until recently heavy-mineral studies of marine sediments were largely restricted to sand fractions. New techniques permitting analysis of decalcified silt fractions have been applied to sediments off the southeastern United States. Our data, which confirm predictions from the basic relationship among grain size, specific gravity, and equivalent hydraulic transport behavior, show that concentrations and average diameters of the silt heavy minerals progressively decrease seaward. Heavy minerals always constitute a substantially greater weight percent of the silt than of the sand fraction. Despite corroded surface textures suggestive of extensive weathering and dissolution, spatial trends in the detrital heavy-mineral populations are predominantly controlled by source and hydraulic factors.

  13. 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.

  14. Long range order and two-fluid behavior in heavy electron materials

    DOE PAGES

    Shirer, Kent R.; Shockley, Abigail C.; Dioguardi, Adam P.; ...

    2012-09-24

    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 lowmore » 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. Lastly, 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.« less

  15. Long range order and two-fluid behavior in heavy electron materials

    SciTech Connect

    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.

    2012-09-24

    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. Lastly, 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.

  16. 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.

  17. 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.

  18. Simulating electron clouds in heavy-ion acceleratorsa)

    NASA Astrophysics Data System (ADS)

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

    2005-05-01

    Contaminating clouds of electrons are a concern for most accelerators of positively 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 magnetized, weakly magnetized, and unmagnetized. The approach to such self-consistency is described, 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 gyroperiod in the magnets. Tests and applications are presented: 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 [L. R. Prost, P. A. Seidl, F. M. Bieniosek, C. M. Celata, A. Faltens, D. Baca, E. Henestroza, J. W. Kwan, M. Leitner, W. L. Waldron, R. Cohen, A. Friedman, D. Grote, S. M. Lund, A. W. Molvik, and E. Morse, "High current transport experiment for heavy ion inertial fusion," Physical Review Special Topics, Accelerators and Beams 8, 020101 (2005)], at Lawrence Berkeley National Laboratory, in which the machine can be flooded with electrons released by impact of the ion beam on 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-time-step mover to accurately calculate the instability.

  19. 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.

  20. Experimental Studies of Electrons in a Heavy-Ion Beam

    SciTech Connect

    Molvik, A W; Seidl, P A; Bieniosek, F M; Cohen, R H; Faltens, A; Friedman, A; Covo, M K; Lund, S M; Prost, L

    2004-06-23

    Electron cloud effects, ECEs, are normally a problem only in ring accelerators. However, heavy-ion induction linacs for inertial fusion energy have an economic incentive to fit beam tubes tightly to intense beams. This places them at risk from electron clouds produced by emission of electrons and gas from walls. We have measured electron and gas emission from 1 MeV K{sup +} impact on surfaces near grazing incidence on the High-Current Experiment (HCX) at LBNL. Electron emission coefficients reach *values of 130, whereas gas desorption coefficients are near 10{sup 4}. Mitigation techniques are being studied: A bead-blasted rough surface reduces electron emission by a factor of 10 and gas desorption by a factor of 2. Diagnostics are installed on HCX, between and within quadrupole magnets, to measure the beam halo loss, net charge and expelled ions, from which we infer gas density, electron trapping, and the effects of mitigation techniques. Here we discuss a new diagnostic technique that measures gas pressure and electron ionization rates within quadrupole magnets during the beam transit.

  1. Floating Heavy Oil Recovery: Current State Analysis

    DTIC Science & Technology

    2006-07-27

    have taken place over the past seven years on a series of pumps known as positive displacement Archimedes ’ screw pumps commonly used in the oil spill...current research into containment strategies and equipment for heavy viscous oil was uncovered during this study. General principles used to...rotated in the water, it created small waves that caused the trail of bitumen to “break” and be pushed away from the skimmer. Operating the drum at

  2. Electronic detection of ultra-heavy nuclei by pyroelectric materials

    NASA Technical Reports Server (NTRS)

    Simpson, J. A.; Tuzzolino, A. J.

    1983-01-01

    A recent prediction by the authors that pyroelectric materials may be capable of detecting ultra-heavy nuclei has been confirmed. Charge pulse signals from pyroelectric crystals of lithium tantalate exposed to Au ions and a pulsed beam of Ni-58 ions, and from pyroelectric films of polyvinylidene fluoride exposed to a pulsed beam of Ni-58 ions, have been measured using pulse electronics with time constants in the microsecond range. These studies show that pyroelectric materials, in general, are capable of detecting incident nuclei having very high mass and charge. In particular, pyroelectric polymers, such as polyvinylidene fluoride, are readily available as inexpensive flexible films. This new class of charged particle detector could eventually find applications in large-area experiments for detection and trajectory determination of low-energy, ultra-heavy nuclei.

  3. Review of highly charged heavy ion production with electron cyclotron resonance ion source (invited)

    NASA Astrophysics Data System (ADS)

    Nakagawa, T.

    2014-02-01

    The electron cyclotron resonance ion source (ECRIS) plays an important role in the advancement of heavy ion accelerators and other ion beam applications worldwide, thanks to its remarkable ability to produce a great variety of intense highly charged heavy ion beams. Great efforts over the past decade have led to significant ECRIS performance improvements in both the beam intensity and quality. A number of high-performance ECRISs have been built and are in daily operation or are under construction to meet the continuously increasing demand. In addition, comprehension of the detailed and complex physical processes in high-charge-state ECR plasmas has been enhanced experimentally and theoretically. This review covers and discusses the key components, leading-edge developments, and enhanced ECRIS performance in the production of highly charged heavy ion beams.

  4. Tamm states in electron plasma

    NASA Astrophysics Data System (ADS)

    2013-11-01

    Researchers have fabricated a voltage-tunable plasmonic crystal in a two-dimensional electron gas that operates at terahertz frequencies. Nature Photonics spoke to Eric Shaner, Greg Dyer and Greg Aizin about the observation of Tamm states at the crystal's edge.

  5. 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.

  6. 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.

  7. Excited state mass spectra of doubly heavy Ξ baryons

    NASA Astrophysics Data System (ADS)

    Shah, Zalak; Rai, Ajay Kumar

    2017-02-01

    In this paper, the mass spectra are obtained for doubly heavy Ξ baryons, namely, Ξ _{cc}+, Ξ _{cc}^{++}, Ξ _{bb}-, Ξ _{bb}0, Ξ _{bc}0 and Ξ _{bc}+. These baryons consist of two heavy quarks ( cc, bb, and bc) with a light ( d or u) quark. The ground, radial, and orbital states are calculated in the framework of the hypercentral constituent quark model with Coulomb plus linear potential. Our results are also compared with other predictions, thus, the average possible range of excited states masses of these Ξ baryons can be determined. The study of the Regge trajectories is performed in ( n, M2) and ( J, M2) planes and their slopes and intercepts are also determined. Lastly, the ground state magnetic moments of these doubly heavy baryons are also calculated.

  8. Heavy pentaquark states and a novel color structure

    NASA Astrophysics Data System (ADS)

    Deng, Chengrong; Ping, Jialun; Huang, Hongxia; Wang, Fan

    2017-01-01

    Encouraged by the observation of the pentaquark states Pc+(4380 ) and Pc+(4450 ), we propose a novel color flux-tube structure, a pentagonal state, for pentaquark states within the framework of a color flux-tube mode involving a five-body confinement potential. Numerical results on the heavy pentaquark states indicate that the states with three color flux-tube structures, diquark, octet, and pentagonal structures, have the closest masses, which can therefore be called QCD isomers, analogous to isomers in chemistry. The pentagonal structure has the lowest energy. The state Pc+(4380 ) can be described as the compact pentaquark state u u d c c ¯ with the pentagonal structure and JP=3/2- in the color flux-tube model. The state Pc+(4450 ) can not be accommodated into the color flux-tube model. The heavy pentaquark states u u d c b ¯, u u d b c ¯, and u u d b b ¯ are predicted in the color flux-tube model. The five-body confinement potential, based on the color flux-tube picture as a collective degree of freedom, is a dynamical mechanism in the formation of the compact heavy pentaquark states.

  9. 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.

  10. Heavy flavor baryon states at the Tevatron

    SciTech Connect

    Seidel, Sally; /New Mexico U.

    2011-08-01

    Precision measurements of the masses and widths of the bottom baryon resonances {Sigma}{sub b} and {Sigma}*{sub b} and charm baryons {Lambda}{sub c}(2595), {Lambda}{sub c}(2625), {Sigma}{sub c}(2455), and {Sigma}{sub c}(2520) are reported. A new measurement of {Lambda}{sub b} production is described. The studies include the first measurement of the widths and isospin mass splittings of the members of the {Sigma}{sub b} family. The charm baryons are examined through their strong decays to the {Lambda}{sub c} ground state, and measurements of their mass differences relative to the ground state, and corresponding decay widths, are reported. The data were collected by the CDF and D0 detectors for 1.96 TeV proton-antiproton collisions during Run II at the Fermilab Tevatron.

  11. Formation of High Charge State Heavy Ion Beams with intense Space Charge

    SciTech Connect

    Seidl, P.A.; Vay, J-L.

    2011-03-01

    High charge-state heavy-ion beams are of interest and used for a number of accelerator applications. Some accelerators produce the beams downstream of the ion source by stripping bound electrons from the ions as they pass through a foil or gas. Heavy-ion inertial fusion (HIF) would benefit from low-emittance, high current ion beams with charge state >1. For these accelerators, the desired dimensionless perveance upon extraction from the emitter is {approx}10{sup -3}, and the electrical current of the beam pulse is {approx}1 A. For accelerator applications where high charge state and very high current are desired, space charge effects present unique challenges. For example, in a stripper, the separation of charge states creates significant nonlinear space-charge forces that impact the beam brightness. We will report on the particle-in-cell simulation of the formation of such beams for HIF, using a thin stripper at low energy.

  12. 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.

  13. 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

  14. Charge-state related effects in sputtering of LiF by swift heavy ions

    NASA Astrophysics Data System (ADS)

    Assmann, W.; Ban-d'Etat, B.; Bender, M.; Boduch, P.; Grande, P. L.; Lebius, H.; Lelièvre, D.; Marmitt, G. G.; Rothard, H.; Seidl, T.; Severin, D.; Voss, K.-O.; Toulemonde, M.; Trautmann, C.

    2017-02-01

    Sputtering experiments with swift heavy ions in the electronic energy loss regime were performed by using the catcher technique in combination with elastic recoil detection analysis. The angular distribution of particles sputtered from the surface of LiF single crystals is composed of a jet-like peak superimposed on a broad isotropic distribution. By using incident ions of fixed energy but different charges states, the influence of the electronic energy loss on both components is probed. We find indications that isotropic sputtering originates from near-surface layers, whereas the jet component may be affected by contributions from depth up to about 150 nm.

  15. 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..

  16. 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.

  17. Can a relativistic differential equation be set up to treat the angularity of the valence electron density in heavy atom clusters?

    NASA Astrophysics Data System (ADS)

    March, N. H.; Glasser, M. L.

    2015-01-01

    This work provides an explicit relativistic non-linear differential equation to estimate the ground-state electron density, and especially its directionality dependence, for large clusters of heavy atoms, such as Pb, at their experimentally measured equilibrium geometry. The study embodies the early theory of Vallarta and Rosen, which seems to us to build a firm foundation on relativistic semi-classical many-electron theory. Assuming a finite nuclear radius for the heavy atoms would be advisable in subsequent numerical applications.

  18. Heavy-Hole States in Germanium Hut Wires

    PubMed Central

    2016-01-01

    Hole spins have gained considerable interest in the past few years due to their potential for fast electrically controlled qubits. Here, we study holes confined in Ge hut wires, a so-far unexplored type of nanostructure. Low-temperature magnetotransport measurements reveal a large anisotropy between the in-plane and out-of-plane g-factors of up to 18. Numerical simulations verify that this large anisotropy originates from a confined wave function of heavy-hole character. A light-hole admixture of less than 1% is estimated for the states of lowest energy, leading to a surprisingly large reduction of the out-of-plane g-factors compared with those for pure heavy holes. Given this tiny light-hole contribution, the spin lifetimes are expected to be very long, even in isotopically nonpurified samples. PMID:27656760

  19. Color spin wave functions of heavy tetraquark states

    NASA Astrophysics Data System (ADS)

    Park, Woosung; Lee, Su Houng

    2014-05-01

    Using the variational method, we calculate the mass of the JP=1+udbbarbbar tetraquark containing two identical heavy antiquarks in a nonrelativistic potential model with color confinement and spin hyperfine interaction. In particular, we extend a previous investigation of the model by Brink and Stancu by investigating the effect of including the color anti-sextet component of the diquark configuration as well as using several more Gaussian parametrization for the L=0 part of the spatial wave function. We find that for the heavy tetraquark, the 66bar component among the color singlet bases is negligible and that the previously used specific Gaussian spatial configuration is good enough in obtaining the ground state energy.

  20. 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.

  1. 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.

  2. Correlated Diskoid-like Electronic States

    PubMed Central

    Baskin, Artem; Sadeghpour, Hossein R.; Král, Petr

    2014-01-01

    We study highly excited diskoid-like electronic states formed in the vicinity of charged and strongly polarizable diskotic nanostructures, such as circular graphene flakes. First, we study the nature of such extended states in a simple two-electron model. The two electrons are attached to a point-like nucleus with a charge 2+, where the material electron is forced to move within a 2D disk area centered at the nucleus, while the extended electron is free to move in 3D. Pronounced and complex correlations are revealed in the diskoid-like states. We also develop semiclassical one-electron models of such diskotic systems and explain how the one-electron and many-electron solutions are related. PMID:25081595

  3. Hot QCD equations of state and relativistic heavy ion collisions

    NASA Astrophysics Data System (ADS)

    Chandra, Vinod; Kumar, Ravindra; Ravishankar, V.

    2007-11-01

    We study two recently proposed equations of state obtained from high-temperature QCD and show how they can be adapted to use them for making predictions for relativistic heavy ion collisions. The method involves extracting equilibrium distribution functions for quarks and gluons from the equation of state (EOS), which in turn will allow a determination of the transport and other bulk properties of the quark gluon-plasma. Simultaneously, the method also yields a quasiparticle description of interacting quarks and gluons. The first EOS is perturbative in the QCD coupling constant and has contributions of O(g5). The second EOS is an improvement over the first, with contributions up to O[g6ln(1/g)]; it incorporates the nonperturbative hard thermal contributions. The interaction effects are shown to be captured entirely by the effective chemical potentials for the gluons and the quarks, in both cases. The chemical potential is seen to be highly sensitive to the EOS. As an application, we determine the screening lengths, which are, indeed, the most important diagnostics for QGP. The screening lengths are seen to behave drastically differently depending on the EOS considered and therefore yield a way to distinguish the two equations of state in heavy ion collisions.

  4. 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

    ... Vehicle Electronic Stability Control Systems AGENCY: National Highway Traffic Safety Administration (NHTSA... No. 136, Electronic Stability Control Systems for Heavy Vehicles (77 FR 30766). The standard would... kilograms (26,000 pounds), to be equipped with an electronic stability control (ESC) system that meets...

  5. 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.

  6. 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.

  7. 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.

  8. Electronic states of GeCl +

    NASA Astrophysics Data System (ADS)

    Dai, Dingguo; Xu, Hua; Balasubramanian, K.

    1995-11-01

    Twenty-eight electronic states of GeCl + are studied using the complete active space self-consistent field (CASSCF) followed by first- and second-order configuration interaction (FOCI, SOCI) methods. Spectroscopic constants of electronic states exhibiting minima are computed.

  9. Equation of state for cold and dense heavy QCD

    NASA Astrophysics Data System (ADS)

    Glesaaen, Jonas; Neuman, Mathias; Philipsen, Owe

    2016-03-01

    A previously derived three-dimensional effective lattice theory describing the thermodynamics of QCD with heavy quarks in the cold and dense region is extended through order ˜ u 5 κ 8 in the combined character and hopping expansion of the original four-dimensional Wilson action. The systematics of the effective theory is investigated to determine its range of validity in parameter space. We demonstrate the severe cut-off effects due to lattice saturation, which afflict any lattice results at finite baryon density independent of the sign problem or the quality of effective theories, and which have to be removed by continuum extrapolation. We then show how the effective theory can be solved analytically by means of a linked cluster expansion, which is completely unaffected by the sign problem, in quantitative agreement with numerical simulations. As an application, we compute the cold nuclear equation of state of heavy QCD. Our continuum extrapolated result is consistent with a polytropic equation of state for non-relativistic fermions.

  10. Electron Spectroscopy In Heavy-Ion Storage Rings: Resonant and Non-Resonant Electron Transfer Processes

    SciTech Connect

    Hagmann, S.; Stoehlker, Th.; Trotsenko, S.; Kozhuharov, Ch.; Spillmann, U.; Bosch, F.; Liesen, D.; Winters, D.; Hillenbrand, P.-M.; Shabaev, V.; Tupitsyn, I.; Kozhedub, Y.; Rothard, H.; Reuschl, R.; Ullrich, J.; Moshammer, R.; Voitkiv, A.; Surzhykov, A.; Fischer, D.; Doerner, R.

    2011-06-01

    Whereas our understanding of total cross sections for ionization and capture processes in ion-atom collisions is widely viewed as having arrived at a state of adequate maturity, the same cannot be said at all about the dynamics of collisions, multi-electron processes or the electron continua (in target and projectile) which are at the origin of total cross sections. We depict how these processes can be studied favourably in storage ring environments. We present examples of resonant and non-resonant electron transfer processes, radiative and non-radiative. This is elucidated via the relation of the electron nucleus bremsstrahlung at the high energy tip of the bremsstrahlung spectrum to the radiative electron capture cusp (RECC) and a new approach to determining molecular orbital binding energies in superheavy quasi-molecules in resonant KK charge transfer.

  11. Targeting excited states in all-trans polyenes with electron-pair states

    NASA Astrophysics Data System (ADS)

    Boguslawski, Katharina

    2016-12-01

    Wavefunctions restricted to electron pair states are promising models for strongly correlated systems. Specifically, the pair Coupled Cluster Doubles (pCCD) ansatz allows us to accurately describe bond dissociation processes and heavy-element containing compounds with multiple quasi-degenerate single-particle states. Here, we extend the pCCD method to model excited states using the equation of motion (EOM) formalism. As the cluster operator of pCCD is restricted to electron-pair excitations, EOM-pCCD allows us to target excited electron-pair states only. To model singly excited states within EOM-pCCD, we modify the configuration interaction ansatz of EOM-pCCD to contain also single excitations. Our proposed model represents a simple and cost-effective alternative to conventional EOM-CC methods to study singly excited electronic states. The performance of the excited state models is assessed against the lowest-lying excited states of the uranyl cation and the two lowest-lying excited states of all-trans polyenes. Our numerical results suggest that EOM-pCCD including single excitations is a good starting point to target singly excited states.

  12. Targeting excited states in all-trans polyenes with electron-pair states.

    PubMed

    Boguslawski, Katharina

    2016-12-21

    Wavefunctions restricted to electron pair states are promising models for strongly correlated systems. Specifically, the pair Coupled Cluster Doubles (pCCD) ansatz allows us to accurately describe bond dissociation processes and heavy-element containing compounds with multiple quasi-degenerate single-particle states. Here, we extend the pCCD method to model excited states using the equation of motion (EOM) formalism. As the cluster operator of pCCD is restricted to electron-pair excitations, EOM-pCCD allows us to target excited electron-pair states only. To model singly excited states within EOM-pCCD, we modify the configuration interaction ansatz of EOM-pCCD to contain also single excitations. Our proposed model represents a simple and cost-effective alternative to conventional EOM-CC methods to study singly excited electronic states. The performance of the excited state models is assessed against the lowest-lying excited states of the uranyl cation and the two lowest-lying excited states of all-trans polyenes. Our numerical results suggest that EOM-pCCD including single excitations is a good starting point to target singly excited states.

  13. 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.

  14. 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.

  15. Manipulation of electronic states and photonic states in nanosilicon

    NASA Astrophysics Data System (ADS)

    Huang, Wei-Qi; Huang, Zhong-Mei; Miao, Xin-Jian; Qin, Chao-Jian; Lv, Quan

    2014-04-01

    On different size hierarchy, period symmetry provides energy band structure, and symmetry breaking produces localized states in gap, for example nanostructures open electronic band gap by confining electrons, but defects in symmetry system produce localized electronic states in gap. The experimental results demonstrate that controlling localized states in gap by changing passivation environment can manipulate emission wavelength, such as stimulated emission at 700 nm due to oxygen passivation and enhanced electroluminescence near 1600 nm due to ytterbium passivation on nanosilicon. In same way, modulating filling fraction and period parameters in photonic crystal enlarges width of photonic band gap (PBG) by confining photons. Symmetry breaking due to defects is effective in manipulating photonic states. New applications for selecting modes in nanolaser and for building single photon source in quantum information are explored by manipulating and coupling between electronic states and photonic states.

  16. State electronic disease surveillance systems --- United States, 2007 and 2010.

    PubMed

    2011-10-21

    The National Electronic Disease Surveillance System (NEDSS) is a web-based infrastructure for public health surveillance data exchange between CDC and the 50 states. In 2007, the Council of State and Territorial Epidemiologists (CSTE) conducted an assessment to evaluate states' electronic disease surveillance capacity. In 2010, CSTE conducted a follow-up assessment to evaluate the operational status and progress of integration, interoperability, and capacity of state electronic disease surveillance systems. This report summarizes the results of that assessment, which indicated a 17.5% increase from 40 states in 2007 to 47 states in 2010 with fully operational general communicable disease (GCD) electronic surveillance systems, a 211.5% increase from 13 to 39 states in the number of systems that were interoperable, a 22.4% increase from 23 to 34 states in the number with integrated systems, and a 20.0% increase to 42 states with the capacity to receive electronic laboratory reports (ELRs). New Centers for Medicare and Medicaid Services rules for meaningful use of health information technology encourage data exchange between electronic health record systems and public health agencies, including submission of ELRs. To meet national goals for health information exchange to improve population health, variation in disease surveillance systems should decrease, and functionality should increase.

  17. Electronic Information Services, Louisiana State University Libraries.

    ERIC Educational Resources Information Center

    Bolner, Smittie; And Others

    Reports prepared by the Louisiana State University (LSU) Libraries Task Force on Electronic Services examine the present level of automated services at the LSU libraries and make recommendations for both long- and short-term plans to handle information in electronic format. The reports, each of which is followed by a list of recommendations, focus…

  18. 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.

  19. Gyrokinetic study of turbulent convection of heavy impurities in tokamak plasmas at comparable ion and electron heat fluxes

    NASA Astrophysics Data System (ADS)

    Angioni, C.; Bilato, R.; Casson, F. J.; Fable, E.; Mantica, P.; Odstrcil, T.; Valisa, M.; ASDEX Upgrade Team; Contributors, JET

    2017-02-01

    In tokamaks, the role of turbulent transport of heavy impurities, relative to that of neoclassical transport, increases with increasing size of the plasma, as clarified by means of general scalings, which use the ITER standard scenario parameters as reference, and by actual results from a selection of discharges from ASDEX Upgrade and JET. This motivates the theoretical investigation of the properties of the turbulent convection of heavy impurities by nonlinear gyrokinetic simulations in the experimentally relevant conditions of comparable ion and electron heat fluxes. These conditions also correspond to an intermediate regime between dominant ion temperature gradient turbulence and trapped electron mode turbulence. At moderate plasma toroidal rotation, the turbulent convection of heavy impurities, computed with nonlinear gyrokinetic simulations, is found to be directed outward, in contrast to that obtained by quasi-linear calculations based on the most unstable linear mode, which is directed inward. In this mixed turbulence regime, with comparable electron and ion heat fluxes, the nonlinear results of the impurity transport can be explained by the coexistence of both ion temperature gradient and trapped electron modes in the turbulent state, both contributing to the turbulent convection and diffusion of the impurity. The impact of toroidal rotation on the turbulent convection is also clarified.

  20. High-quality single crystal growth and strongly correlated electronic states in rare earth and actinide compounds

    NASA Astrophysics Data System (ADS)

    Ōnuki, Yoshichika; Honda, Fuminori; Hirose, Yusuke; Settai, Rikio; Takeuchi, Tetsuya

    2016-11-01

    We review the nature of strongly correlated electronic states in rare earth and actinide compounds, focusing on localized versus itinerant electronic states in CeRhIn5, quantum critical phenomena in YbIr2Zn20, residual resistivity in CeCu6, metamagnetism in heavy fermion compounds, and unconventional superconductivity in CeIrSi3 without inversion symmetry in the crystal structure, emphasizing that sample quality is essentially important to clarify the characteristic features for the heavy fermion compounds.

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

    PubMed

    Donovan, Robert J; Lawley, Kenneth P; Ridley, Trevor

    2015-05-28

    We report the identification of heavy Rydberg resonances in the ion-pair spectra of I2, Cl2, ICl, and IBr. Extensive vibrational progressions are analysed in terms of the energy dependence of the quantum defect δ(Eb) 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(Eb), 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(-1) below dissociation. The rapid semi-classical calculation of δ(Eb) 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.

  2. 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.

  3. Average charge states of heavy and superheavy ions passing through a rarified gas: Theory and experiment

    NASA Astrophysics Data System (ADS)

    Khuyagbaatar, J.; Shevelko, V. P.; Borschevsky, A.; Düllmann, Ch. E.; Tolstikhina, I. Yu.; Yakushev, A.

    2013-10-01

    The average charge states q¯ of heavy and superheavy ions (atomic numbers Z=80-114) passing through He gas are studied experimentally and theoretically. Experimental data were measured at the gas-filled recoil separator, i.e., the TransActinide Separator and Chemistry Apparatus (TASCA) at GSI Darmstadt, for ion energies of a few hundred keV/u at gas pressures of 0.2 to 2.0 mbar. An attempt is made to describe experimental q¯ values by means of atomic calculations of the binding energies and electron-loss and electron-capture cross sections. The influence of the gas-density effect is included in the calculations. The calculated q¯ reproduce the experimental values for elements with Z=80-114 within 20%. A comparison with different semiempirical models is presented as well, including a local fit of high accuracy, which is often used in superheavy-element experiments to estimate the average charge states of heavy ions, e.g., at the gas-filled recoil separator TASCA. The q¯ values for elements with Z=115, 117, 119, and 120 at He-gas pressure of 0.8 mbar are predicted.

  4. Unoccupied electronic states of Ru(0001)

    NASA Astrophysics Data System (ADS)

    del Campo, Valeria; Correa, Julián-David; Correa-Puerta, Jonathan; Kroeger, Daniel; Häberle, Patricio

    2016-11-01

    This report presents a combined theoretical and experimental description of the unoccupied electronic states of Ru(0001), along the Γ̅M̅ high symmetry direction of the Brillouin zone. A direct comparison between angle-resolved inverse photoemission spectroscopy and ab initio calculations of the 3-dimensional (3D) electronic structure of Ru(0001) have been used to determine the energy dispersion and the identification of different states and surface resonances. Both, measurements and calculations, complement previous reports regarding the electronic structure of Ru.

  5. Electron-Cloud Simulation and Theory for High-Current Heavy-Ion Beams

    SciTech Connect

    Cohen, R; Friedman, A; Lund, S; Molvik, A; Lee, E; Azevedo, T; Vay, J; Stoltz, P; Veitzer, S

    2004-07-26

    Stray electrons can arise in positive-ion 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 summarize the distinguishing features of electron cloud issues in heavy-ion-fusion accelerators and a plan for developing a self-consistent simulation capability for heavy-ion beams and electron clouds. We also present results from several ingredients in this capability: (1) We calculate the electron cloud produced by electron desorption from computed beam-ion loss, which illustrates the importance of retaining ion reflection at the walls. (2) We simulate of the effect of specified electron cloud distributions on ion beam dynamics. 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 have significant impact. We identify an instability associated with a resonance between the beam-envelope ''breathing'' mode and the electron perturbation. We estimate its growth rate, which is moderate (compared to the reciprocal of a typical pulse duration). One conclusion from this study is that heavy-ion beams are surprisingly robust to electron clouds, compared to a priori expectations. (3) We report first results from a long-timestep algorithm for electron dynamics, which holds promise for efficient simultaneous solution of electron and ion dynamics.

  6. 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.

  7. Electron ejection by heavy particles as precursor of track formation in condensed matter

    NASA Astrophysics Data System (ADS)

    Rothard, Hermann

    2004-08-01

    The detailed knowledge of the structure of ion tracks is a key issue for our understanding of radiation effects in condensed matter. Important examples are the radial energy deposition profile by electronic excitation for numerical simulations of track formation (via "Coulomb explosion" or "thermal spike") in inert matter, and calculations of the RBE (relative biological effectiveness) of heavy particles in living matter (with important applications in dosimetry and hadrontherapy). In both cases, differential electron ejection cross sections are used as input parameter. The precursor of track formation is thus electron ejection from target atoms, or from the projectile itself. These primary electrons and their subsequent secondary interactions lead to the deposition of energy along and around the ion trajectory. We first briefly discuss "primary ionization" (binary encounter and soft electron emission, multiple collision sequences: "Fermi shuttle") common to single atoms (gas targets) and condensed matter. Then, specific effects in condensed matter (electron transport, jet-like electron spikes, wake effects due to collective excitation of plasmons and emission of shock wave electrons) will be presented. Finally, we concentrate on effects connected to the high density of deposited energy and strong perturbation induced by heavy particles such as heavy ions and clusters (reduction effects due to screening, transport and "sweeping away", multiple ionization, electronic temperatures from Auger spectroscopy).

  8. Heavy ion beam-ionosphere interactions: Electron acceleration

    SciTech Connect

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

    1985-10-01

    Operation of a divergent 25-eV Ar/sup +/ gun within an auroral arc produced dramatic changes in the flux of electrons with energies between 1 keV and the 88-eV detector cutoff. The observations suggest that intense return currents flowed parallel to B/sub 0/ to neutralize the Ar/sup +/ beam, particularly within a few meters of the rocket. These neutralization currents were carried above and below the rocket by the few-eV electrons which were emitted by the gun and by colder ionospheric electrons. Such low-energy electrons could not be measured directly by detectors on the rocket. We concluded that generation of strong field-aligned return currents was the most important effect of ion gun operation, and that these field aligned currents were responsible for many other observable effects. Downgoing hectovolt electrons appear to have been accelerated because of interactions with waves or quasi-stationary electric fields that were generated by the field-aligned current. This acceleration took place throughout a cylinder centered on the rocket,with a radius of at least several meters. Acceleration of hectovolt electrons depended surprisingly little on the direction in which the Ar/sup +/ gun was pointing.

  9. 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.

  10. Accomplishments of the heavy electron particle accelerator program

    SciTech Connect

    Neuffer, D.; Stratakis, D.; Palmer, M.; Delahaye, J-P; Summers, D.; Ryne, R.; Cummings, M. A.

    2016-10-18

    The Muon Accelerator Program (MAP) has completed a four-year study on the feasibility of muon colliders and on using stored muon beams for neutrinos. That study was broadly successful in its goals, establishing the feasibility of heavy lepton colliders (HLCs) from the 125 GeV Higgs Factory to more than 10 TeV, as well as exploring using a μ storage ring (MSR) for neutrinos, and establishing that MSRs could provide factory-level intensities of νe ($\\bar{ve}$) and $\\bar{vμ}$ (νμ) beams. The key components of the collider and neutrino factory systems were identified. Feasible designs and detailed simulations of all of these components have been obtained, including some initial hardware component tests, setting the stage for future implementation where resources are available and the precise physics goals become apparent.

  11. 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.

  12. Proteins as solid-state electronic conductors.

    PubMed

    Ron, Izhar; Pecht, Israel; Sheves, Mordechai; Cahen, David

    2010-07-20

    Protein structures can facilitate long-range electron transfer in solution. But a fundamental question remains: can these structures also serve as solid-state electronic conductors? Answering this question requires methods for studying conductivity of the "dry" protein (which only contains tightly bound structured water molecules) sandwiched between two electronic conductors in a solid-state type configuration. If successful, such systems could serve as the basis for future, bioinspired electronic device technology. In this Account, we survey, analyze, and compare macroscopic and nanoscopic (scanning probe) solid-state conductivities of proteins, noting the inherent constraints of each of these, and provide the first status report on this research area. This analysis shows convincing evidence that "dry" proteins pass orders of magnitude higher currents than saturated molecules with comparable thickness and that proteins with known electrical activity show electronic conductivity, nearly comparable to that of conjugated molecules ("wires"). These findings suggest that the structural features of proteins must have elements that facilitate electronic conductivity, even if they do not have a known electron transfer function. As a result, proteins could serve not only as sensing, polar,or photoactive elements in devices (such as field-effect transistor configurations) but also as electronic conductors. Current knowledge of peptide synthesis and protein modification paves the way toward a greater understanding of how changes in a protein's structure affect its conductivity. Such an approach could minimize the need for biochemical cascades in systems such as enzyme-based circuits, which transduce the protein's response to electronic current. In addition, as precision and sensitivity of solid-state measurements increase, and as knowledge of the structure and function of "dry" proteins grows, electronic conductivity may become an additional approach to study electron

  13. TCEQ State of Texas Environmental Electronic Reporting System (STEERS)

    EPA Pesticide Factsheets

    TCEQ's State of Texas Environmental Electronic Reporting System (STEERS) is an existing electronic document receiving system for collecting numerous reports required under the state's EPA-authorized programs.

  14. Standardless Quantification of Heavy Elements by Electron Probe Microanalysis.

    PubMed

    Moy, Aurélien; Merlet, Claude; Dugne, Olivier

    2015-08-04

    Absolute Mα and Mβ X-ray intensities were measured for the elements Pt, Au, Pb, U, and Th by electron impact for energies ranging from 6 to 38 keV. Experimental data were obtained by measuring the X-ray intensity emitted from bulk samples with an electron microprobe using high-resolution wavelength-dispersive spectrometers. Recorded X-ray intensities were converted into absolute X-ray yields by evaluation of the detector efficiency and then compared with X-ray intensities calculated by means of Monte Carlo simulations. Simulated Mα and Mβ X-ray intensities were found to be in good agreement with the measurements, allowing their use in standardless quantification methods. A procedure and a software program were developed to accurately obtain virtual standard values. Standardless quantifications of Pb and U were tested on standards of PbS, PbTe, PbCl2, vanadinite, and UO2.

  15. 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…

  16. Heavy-fermion superconductivity in the quadrupole ordered state of PrV2Al20.

    PubMed

    Tsujimoto, Masaki; Matsumoto, Yosuke; Tomita, Takahiro; Sakai, Akito; Nakatsuji, Satoru

    2014-12-31

    PrV2Al20 is a rare example of a heavy-fermion system based on strong hybridization between conduction electrons and nonmagnetic quadrupolar moments of the cubic Γ3 ground doublet. Here, we report that a high-quality single crystal of PrV2Al20 exhibits superconductivity at Tc=50  mK in the antiferroquadrupole-ordered state under ambient pressure. The heavy-fermion character of the superconductivity is evident from the specific heat jump of ΔC/T∼0.3  J/mol K(2) and the effective mass m*/m0∼140 estimated from the temperature dependence of the upper critical field. Furthermore, the high-quality single crystals exhibit double transitions at TQ=0.75  K and T*=0.65  K associated with quadrupole and octupole degrees of freedom of the Γ3 doublet. In the ordered state, the specific heat C/T shows a T(3) dependence, indicating the gapless mode associated with the quadrupole order, the octupole order, or both. The strong sensitivity to impurity of the superconductivity suggests unconventional character due to significant quadrupolar fluctuations.

  17. Initial state fluctuations and final state correlations in relativistic heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Luzum, Matthew; Petersen, Hannah

    2014-06-01

    We review the phenomenology and theory of bulk observables in ultra-relativistic heavy-ion collisions, focusing on recent developments involving event-by-event fluctuations in the initial stages of a heavy-ion collision, and how they manifest in observed correlations. We first define the relevant observables and show how each measurement is related to underlying theoretical quantities. Then we review the prevailing picture of the various stages of a collision, including the state-of-the-art modeling of the initial stages of a collision and subsequent hydrodynamic evolution, as well as hadronic scattering and freeze-out in the later stages. We then discuss the recent results that have shaped our current understanding and identify the challenges that remain. Finally, we point out open issues and the potential for progress in the field.

  18. 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)

  19. String Models for the Heavy Quark-Antiquark Bound States.

    NASA Astrophysics Data System (ADS)

    Tse, Sze-Man

    1988-12-01

    The heavy quark-antiquark bound state is examined in the phenomenological string models. Specifically, the Nambu-Goto model and the Polyakov's smooth string model are studied in the large-D limit, D being the number of transverse space-time dimensions. The static potential V(R) is extracted in both models in the large-D limit. In the former case, this amounts to the usual saddle point calculation. In the latter case, the renormalized, physical string tension is expressed in terms of the bare string tension and the extrinsic curvature coupling. A systematic loop expansion of V(R) is developed and carried out explicitly to one loop order, with the two loops result presented without detail. For large separations R, the potential is linear in R with corrections of order 1/R. The coefficient of the 1/R Luscher term has the universal value -piD/24 to any finite order in the loop expansion. For very small separations R, the potential V(R) is also proportional to 1/R with a coefficient twice that of Luscher's term. The corrections are logarithmically small. Polyakov's smooth string model is extended to the finite temperature situation. The temperature dependence of the string tension is investigated in the large-D limit. The effective string tension is calculated to the second order in the loop expansion. At low temperature, it differs from that of the Nambu-Goto model only by terms that fall exponentially with inverse temperature. Comparison of the potential V(R) in the smooth string model with lattice gauge calculation and hadron spectroscopy data yields a consistent result.

  20. O^- channels of Dissociative Electron Attachment to water and heavy water molecules

    NASA Astrophysics Data System (ADS)

    Adaniya, Hidehito; Rudek, Benedikt; Osipov, Timur; Lee, Sun; Weber, Thorsten; Hertlein, Marcus; Schoeffler, Markus; Prior, Mike; Belkacem, Ali

    2009-05-01

    A COLTRIM technique is modified to measure the kinetic energy and angular distribution of O^- ions arising from dissociative electron attachment to water and heavy water molecules. A low energy pulsed electron, an effusive water target, a pulsed extraction plate are used in combination with the COLTRIMS spectrometer. The spectrometer carries an electrostatic lens system to compensate the effusiveness of the target. This technique is applied to study the O^- channels in the three Feshbach resonances of water and heavy water anion. The measured kinetic energy release will give the energy partitioning among the fragments, and the means to identify the two-body and three-body breakup channels. The angular distribution of the O^- ions with respect to the electron beam is found to reflect well the breakup dynamics of the H2O^- at the dissociation. The experimental results are compared with the theoretical predictions.

  1. Effect of Track Potentials on the Movement of Secondary Electrons due to Irradiation of Heavy Ions

    NASA Astrophysics Data System (ADS)

    Moribayashi, Kengo

    2017-02-01

    This paper quantitatively discusses the effect of positive nuclear track potentials on the motion of secondary electrons due to heavy-ion irradiation using a simulation model. This model reproduces the tendency of measurement of the number of secondary electrons. Using this model, physical phenomena can be treated closer to reality than those using the conventional models. Here, the track potential is defined as the potential formed from the electric field near the track of a heavy ion. This effect is expected to be given as functions of not only the mean paths (τ) between incident ion impact ionization events but also the average initial secondary electron energies. The results shown in this paper indicate that the effect of the track potential is mainly determined by τ.

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

    PubMed

    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.

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

    PubMed

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

    2014-02-01

    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(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(5+) ion beam was got when work gas was CH4 while about 262 eμA of C(5+) ion beam was obtained when work gas was C2H2 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

    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 C5+ 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 C5+ ion beam was got when work gas was CH4 while about 262 eμA of C5+ ion beam was obtained when work gas was C2H2 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.

  5. Observation of Electron Fishbone-Like Instabilities in EAST Heavy Impurity Ohmic Plasma

    NASA Astrophysics Data System (ADS)

    Xu, Li-Qing; Hu, Li-Qun; East Team

    2013-07-01

    The transient burst of an internal kink mode is first observed in EAST heavy impurity ohmic plasma. The features of the electron fishbone-like mode are presented, and the fishbone-like instabilities are found to be driven by the trapped supra-thermal electrons. The processional frequency of the trapped supra-thermal electrons is calculated with different discharge parameters. The results indicate that the calculated processional frequency is consistent with the experimental observations. Furthermore, we also find that the frequency chirping of the long-lived mode is related to the evolution of the safety factor profile.

  6. 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.

  7. 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 {ge}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{sup o} and 88{sup o} 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.

  8. Electronic ground state of Ni2+

    NASA Astrophysics Data System (ADS)

    Zamudio-Bayer, V.; Lindblad, R.; Bülow, C.; Leistner, G.; Terasaki, A.; v. Issendorff, B.; Lau, J. T.

    2016-11-01

    The 9/2 4Φ ground state of the Ni2+ diatomic molecular cation is determined experimentally from temperature and magnetic-field-dependent x-ray magnetic circular dichroism spectroscopy in a cryogenic ion trap, where an electronic and rotational temperature of 7.4 ±0.2 K was reached by buffer gas cooling of the molecular ion. The contribution of the spin dipole operator to the x-ray magnetic circular dichroism spin sum rule amounts to 7 Tz =0.17 ± 0.06 μB per atom, approximately 11% of the spin magnetic moment. We find that, in general, homonuclear diatomic molecular cations of 3d transition metals seem to adopt maximum spin magnetic moments in their electronic ground states.

  9. Electronic States in Capped Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Yaguchi, Tatsuya; Ando, Tsuneya

    2001-05-01

    Scattering of an electron wave at various caps closing an armchair nanotube is studied. The reflection coefficients can be understood as an effective shift in boundary position and phase shift at the boundary. The phase shift is approximately given by π for states with parity + and 0 for states with parity -, respectively. The effective position is approximated by (1/4)P, where P is the height of an equilateral triangle having a base line determined by neighboring five-membered rings located at the boundary between the tube and the cap. The electronic structure of a finite-length armchair nanotube closed by a cap can be calculated with the use of the phase shifts.

  10. MHD Equation of State with Relativistic Electrons

    NASA Astrophysics Data System (ADS)

    Gong, Zhigang; Däppen, Werner; Zejda, Ladislav

    2001-01-01

    The Mihalas-Däppen-Hummer (MHD) equation of state does not include the effect of relativistic partially degenerate electrons, although nonrelativistic partial degeneracy is taken into account. The discovery of a relativistic correction in helioseismology forces us to perform an appropriate upgrade of the MHD equation of state. We have adopted the method of J. M. Aparicio to evaluate the relativistic Fermi-Dirac functions. Our calculations confirm the validity of the approximation used, which works well for the weakly relativistic electrons under solar-center conditions. However, our results will also provide reliable thermodynamic quantities in the stronger relativistic regime as found in more massive stars. Since a particular feature of the original MHD papers was an explicit list of the adopted free energy and its first- and second-order analytical derivatives, we give the corresponding relativistic quantities in the Appendix.

  11. Spatial assessment of soil contamination by heavy metals from informal electronic waste recycling in Agbogbloshie, Ghana

    PubMed Central

    Greve, Klaus; Atiemo, Sampson M.

    2016-01-01

    Objectives This study examined the spatial distribution and the extent of soil contamination by heavy metals resulting from primitive, unconventional informal electronic waste recycling in the Agbogbloshie e-waste processing site (AEPS) in Ghana. Methods A total of 132 samples were collected at 100 m intervals, with a handheld global position system used in taking the location data of the soil sample points. Observing all procedural and quality assurance measures, the samples were analyzed for barium (Ba), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb), and zinc (Zn), using X-ray fluorescence. Using environmental risk indices of contamination factor and degree of contamination (Cdeg), we analyzed the individual contribution of each heavy metal contamination and the overall Cdeg. We further used geostatistical techniques of spatial autocorrelation and variability to examine spatial distribution and extent of heavy metal contamination. Results Results from soil analysis showed that heavy metal concentrations were significantly higher than the Canadian Environmental Protection Agency and Dutch environmental standards. In an increasing order, Pb>Cd>Hg>Cu>Zn>Cr>Co>Ba>Ni contributed significantly to the overall Cdeg. Contamination was highest in the main working areas of burning and dismantling sites, indicating the influence of recycling activities. Geostatistical analysis also revealed that heavy metal contamination spreads beyond the main working areas to residential, recreational, farming, and commercial areas. Conclusions Our results show that the studied heavy metals are ubiquitous within AEPS and the significantly high concentration of these metals reflect the contamination factor and Cdeg, indicating soil contamination in AEPS with the nine heavy metals studied. PMID:26987962

  12. Heavy Atom Effect on Photophysical Deactivation of Molecular Triplet States

    NASA Astrophysics Data System (ADS)

    Gastilovich, E. A.; Serov, S. A.; Korol'Kova, N. V.; Klimenko, V. G.

    2000-03-01

    The decrease in the spin-orbit (SO) interaction with increasing number of chlorine atoms in molecules of dibenzo- p-dioxine derivatives is found and explained. The heavy atom effect on components of the rate constant of phosphorescence k ph=k SO+k VSO related to SO and vibronic-spin-orbit (VSO) interactions is quantitatively estimated.

  13. Recollections of the electron crystallographic heavy atom derivative search of purple membrane: the quest for EM structure determination.

    PubMed

    Ceska, T A

    1999-09-01

    The use of multiple isomorphous replacement in protein electron crystallography for phase determination has been systematically studied only for purple membrane, even though the use of heavy atoms or heavy atom clusters has been used on many occasions in electron microscopy for locating domains or subunits in protein assemblies. The background behind the structure determination of bacteriorhodopsin, the protein component of purple membranes, is summarized and an evaluation of the strengths and weaknesses of using isomorphous replacement in electron crystallography is discussed.

  14. Sensitivity of Δ G Through Open Heavy Quark Production using Electron Decay Channels at PHENIX

    NASA Astrophysics Data System (ADS)

    Xie, Wei

    2000-10-01

    The PHENIX experiment at Relativistic Heavy Ion Collider at Brookhaven National Laboratory is capable of directly measuring the portion of the proton spin carri ed by gluons spin(Δ G)in several channels including direct photon product ion, π production and heavy flavor production. The extraction of Δ G throu gh independent channels gives good control of systematic and theoretical uncerta inty. In this paper we report on PHENIX's Δ G measurement in open heavy q uark production using electron decay channels. Heavy flavor production, cbarc and bbarb, is dominated by gluon-gluon interactions and gives rise to a double spin asymmetry A_LL ~ fracΔ G(x_A)G(x_A)øtimes fracΔ G(x_B)G(x_B)øtimes a_LL^ggarrow qbarq , from which Δ G can be extracted. We will report a full detector simulation which includes the effects of electron trigger and dilutions due to the conversion in inner chamber and π^0 Dalitz decays.

  15. 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.

  16. Emergence of superconductivity in the canonical heavy-electron metal YbRh₂Si₂.

    PubMed

    Schuberth, Erwin; Tippmann, Marc; Steinke, Lucia; Lausberg, Stefan; Steppke, Alexander; Brando, Manuel; Krellner, Cornelius; Geibel, Christoph; Yu, Rong; Si, Qimiao; Steglich, Frank

    2016-01-29

    The smooth disappearance of antiferromagnetic order in strongly correlated metals commonly furnishes the development of unconventional superconductivity. The canonical heavy-electron compound YbRh2Si2 seems to represent an apparent exception from this quantum critical paradigm in that it is not a superconductor at temperature T ≥ 10 millikelvin (mK). Here we report magnetic and calorimetric measurements on YbRh2Si2, down to temperatures as low as T ≈ 1 mK. The data reveal the development of nuclear antiferromagnetic order slightly above 2 mK and of heavy-electron superconductivity almost concomitantly with this order. Our results demonstrate that superconductivity in the vicinity of quantum criticality is a general phenomenon.

  17. Heavy ion beam loss mechanisms at an electron-ion collider

    NASA Astrophysics Data System (ADS)

    Klein, Spencer R.

    2014-12-01

    There are currently several proposals to build a high-luminosity electron-ion collider, to study the spin structure of matter and measure parton densities in heavy nuclei, and to search for gluon saturation and new phenomena like the colored glass condensate. These measurements require operation with heavy nuclei. We calculate the cross sections for two important processes that will affect accelerator and detector operations: bound-free pair production and Coulomb excitation of the nuclei. Both of these reactions have large cross sections, 28-56 mb, which can lead to beam ion losses, produce beams of particles with altered charge:mass ratio, and produce a large flux of neutrons in zero degree calorimeters. The loss of beam particles limits the sustainable electron-ion luminosity to levels of several times 1032/cm2/s .

  18. Recoherence by squeezed states in electron interferometry

    SciTech Connect

    Hsiang, J.-T.; Ford, L. H.

    2008-09-15

    Coherent electrons coupled to the quantized electromagnetic field undergo decoherence which can be viewed as due either to fluctuations of the Aharonov-Bohm phase or to photon emission. When the electromagnetic field is in a squeezed vacuum state, it is possible for this decoherence to be reduced, leading to the phenomenon of recoherence. This recoherence effect requires electrons which are emitted at selected times during the cycle of the excited mode of the electromagnetic field. We show that there are bounds on the degree of recoherence which are analogous to quantum inequality restriction on negative energy densities in quantum field theory. We make some estimates of the degree of recoherence, and show that although small, it is in principle observable.

  19. Final Technical Report, Grant DE-FG02-91ER45443: Heavy fermions and other highly correlated electron systems

    SciTech Connect

    Schlottmann, P.

    1998-10-12

    Properties of highly correlated electrons, such as heavy fermion compounds, metal-insulator transitions, one-dimensional conductors and systems of restricted dimensionality are studied theoretically. The main focus is on Kondo insulators and impurity bands due to Kondo holes, the low-temperature magnetoresistivity of heavy fermion alloys, the n-channel Kondo problem, mesoscopic systems and one-dimensional conductors.

  20. Heavy-Rydberg ion-pair formation in Rydberg atom collisions: Probing dissociative electron attachment

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    While electron transfer in Rydberg atom collisions with attaching targets forms a valuable technique with which to create heavy-Rydberg ion pairs to examine their properties, we demonstrate here that measurements of their velocity distributions can also provide insights into the behavior of the excited intermediates formed through initial electron transfer. The experimental results are analyzed with the aid of a Monte Carlo collision code that models the details of electron transfer reactions. Results for a variety of targets are presented that demonstrate the use of this approach to examine the dynamics of dissociative electron attachment, the lifetimes of the intermediates created, and the channels by which they decay. Research supported by the Robert A. Welch Foundation under Grant C-0734.

  1. 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.

  2. Metastable and spin-polarized states in electron systems with localized electron-electron interaction

    NASA Astrophysics Data System (ADS)

    Sablikov, Vladimir A.; Shchamkhalova, Bagun S.

    2014-05-01

    We study the formation of spontaneous spin polarization in inhomogeneous electron systems with pair interaction localized in a small region that is not separated by a barrier from surrounding gas of non-interacting electrons. Such a system is interesting as a minimal model of a quantum point contact in which the electron-electron interaction is strong in a small constriction coupled to electron reservoirs without barriers. Based on the analysis of the grand potential within the self-consistent field approximation, we find that the formation of the polarized state strongly differs from the Bloch or Stoner transition in homogeneous interacting systems. The main difference is that a metastable state appears in the critical point in addition to the globally stable state, so that when the interaction parameter exceeds a critical value, two states coexist. One state has spin polarization and the other is unpolarized. Another feature is that the spin polarization increases continuously with the interaction parameter and has a square-root singularity in the critical point. We study the critical conditions and the grand potentials of the polarized and unpolarized states for one-dimensional and two-dimensional models in the case of extremely small size of the interaction region.

  3. 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.

  4. 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.

  5. Strongly correlated electron physics: From Kondo and spin glasses to heavy fermions, hidden order and quantum phase transitions

    NASA Astrophysics Data System (ADS)

    Bennett, Edmund; Mydosh, J. A.

    2012-09-01

    We summarize the development of strongly correlated electron physics (SCEP) stimu-lated from the 1930's when a strange upturn was found in the electrical resistivity at low temper-atures. It was only in 1965 that this effect was explained as a many-body, spin-flip, scattering of electrons from a magnetic impurity, i.e., the Kondo effect. This marked the beginning of SCEP. When the concentration of these impurities is increased so that they can randomly interact we have the spin glasses and their unconventional, yet classical phase transition. Spin glass physics formed the background know-how for the combination of two ferromagnetic layers separated by a non-magnetic spacer which generated the the giant magnetic resistance and it many applications in com-puter hardware. By fabricating a lattice of the magnetic species, viz., an intermetallic compound based upon certain rare-earth and actinide elements, we then create a heavy Fermi liquid that can support most unusual ground-state behavior, e.g., unconventional superconductivity. This leads to the mysterious and still unexplained "hidden order" phase transition of URu2Si2. Finally, since the heavy fermions commonly exhibit zero temperature phase transitions, aka, quantum phase transitions when tuned with pressure, magnetic field or doping, we are at the summit of today's SCEP - the prime topic of 2012 condensed matter physics.

  6. Polar Kerr effect studies of time reversal symmetry breaking states in heavy fermion superconductors

    NASA Astrophysics Data System (ADS)

    Schemm, E. R.; Levenson-Falk, E. M.; Kapitulnik, A.

    2017-04-01

    The connection between chiral superconductivity and topological order has emerged as an active direction in research as more instances of both have been identified in condensed matter systems. With the notable exception of 3He-B, all of the known or suspected chiral - that is to say time-reversal symmetry-breaking (TRSB) - superfluids arise in heavy fermion superconductors, although the vast majority of heavy fermion superconductors preserve time-reversal symmetry. Here we review recent experimental efforts to identify TRSB states in heavy fermion systems via measurement of polar Kerr effect, which is a direct consequence of TRSB.

  7. Self-Consistent Simulations of Heavy-Ion Beams Interacting with Electron-Clouds

    SciTech Connect

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

    2006-08-04

    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.

  8. Imaging of localized electronic states at a nonconducting surface by single-electron tunneling force microscopy.

    PubMed

    Bussmann, Ezra B; Zheng, Ning; Williams, Clayton C

    2006-11-01

    Localized electronic states near a nonconducting SiO(2) surface are imaged on a approximately 1 nm scale by single-electron tunneling between the states and a scanning probe tip. Each tunneling electron is detected by electrostatic force. The images represent the number of tunneling electrons at each spatial location. The spatial resolution of the single electron tunneling force microscope is determined by quantum mechanical tunneling, providing new atomic-scale access to electronic states in dielectric surfaces and nonconducting nanostructures.

  9. 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.

  10. 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.

  11. 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

  12. Direct evidence for a magnetic f-electron-mediated pairing mechanism of heavy-fermion superconductivity in CeCoIn5.

    PubMed

    Van Dyke, John S; Massee, Freek; Allan, Milan P; Davis, J C Séamus; Petrovic, Cedomir; Morr, Dirk K

    2014-08-12

    To identify the microscopic mechanism of heavy-fermion Cooper pairing is an unresolved challenge in quantum matter studies; it may also relate closely to finding the pairing mechanism of high-temperature superconductivity. Magnetically mediated Cooper pairing has long been the conjectured basis of heavy-fermion superconductivity but no direct verification of this hypothesis was achievable. Here, we use a novel approach based on precision measurements of the heavy-fermion band structure using quasiparticle interference imaging to reveal quantitatively the momentum space (k-space) structure of the f-electron magnetic interactions of CeCoIn5. Then, by solving the superconducting gap equations on the two heavy-fermion bands Ek(α,β) with these magnetic interactions as mediators of the Cooper pairing, we derive a series of quantitative predictions about the superconductive state. The agreement found between these diverse predictions and the measured characteristics of superconducting CeCoIn5 then provides direct evidence that the heavy-fermion Cooper pairing is indeed mediated by f-electron magnetism.

  13. 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.

  14. Enhanced negative ion formation via electron attachment to electronically-excited states

    SciTech Connect

    Pinnaduwage, L.A. |

    1995-12-31

    Recent basic studies on electron attachment to laser-excited molecules show that electron attachment to electronically-excited states can have orders of magnitude larger cross sections compared to the respective ground electronic states. Even though systematic studies have not been conducted, there are indications that electronically-excited states may play a significant role in negative ion formation in gas discharges. The high-lying Rydberg states could be of particular significance since, (i) their production efficiencies are high, and (ii) they have comparatively long lifetimes. Such states could be populated in discharge sources via direct electron impact or via excitation transfer from metastable states of inert gases.

  15. Double scattering production of two positron-electron pairs in ultraperipheral heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Kłusek-Gawenda, Mariola; Szczurek, Antoni

    2016-12-01

    We present first measurable predictions for electromagnetic (two-photon) double scattering production of two positron-electron pairs in ultraperipheral heavy-ion collisions at LHC. Measurable cross sections are obtained with realistic cuts on electron/positron (pseudo)rapidities and transverse momenta for the ALICE and ATLAS or CMS experiments. The predictions for total and differential cross sections are presented. We show also two-dimensional distributions in rapidities of the opposite-sign (from the same or different subcollisions) and of the same-sign (e+e+ or e-e-) electrons and in rapidity distance between them. Expected number of events are presented and discussed. Our calculations strongly suggest that relevant measurements with the help of ATLAS, CMS and ALICE detectors are possible in a near future. We show and compare energy dependence of the cross sections for one-pair and two-pair production.

  16. 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.

  17. Bound states of a light atom and two heavy dipoles in two dimensions

    NASA Astrophysics Data System (ADS)

    Rosa, D. S.; Bellotti, F. F.; Jensen, A. S.; Krein, G.; Yamashita, M. T.

    2016-12-01

    We study a three-body system, formed by a light particle and two identical heavy dipoles, in two dimensions in the Born-Oppenheimer approximation. We present the analytic light-particle wave function resulting from an attractive zero-range potential between the light and each of the heavy particles. It expresses the large-distance universal properties which must be reproduced by all realistic short-range interactions. We calculate the three-body spectrum for zero heavy-heavy interaction as a function of light to heavy mass ratio. We discuss the relatively small deviations from Coulomb estimates and the degeneracies related to radial nodes and angular momentum quantum numbers. We include a repulsive dipole-dipole interaction and investigate the three-body solutions as functions of strength and dipole direction. Avoided crossings occur between levels localized in the emerging small and large-distance minima, respectively. The characteristic exchange of properties such as mean-square radii are calculated. Simulation of quantum information transfer is suggested. For large heavy-heavy-particle repulsion all bound states have disappeared into the continuum. The corresponding critical strength is inversely proportional to the square of the mass ratio, far from the linear dependence from the Landau criterion.

  18. 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.

  19. 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.

  20. 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.

  1. Potentiometric electronic tongue-flow injection analysis system for the monitoring of heavy metal biosorption processes.

    PubMed

    Wilson, D; del Valle, M; Alegret, S; Valderrama, C; Florido, A

    2012-05-15

    An automated flow injection potentiometric (FIP) system with electronic tongue detection (ET) is used for the monitoring of biosorption processes of heavy metals on vegetable wastes. Grape stalk wastes are used as biosorbent to remove Cu(2+) ions in a fixed-bed column configuration. The ET is formed by a 5-sensor array with Cu(2+) and Ca(2+)-selective electrodes and electrodes with generic response to heavy-metals, plus an artificial neural network response model of the sensor's cross-response. The real-time monitoring of both the Cu(2+) and the cation exchanged and released (Ca(2+)) in the effluent solution is performed by using flow-injection potentiometric electronic tongue system. The coupling of the electronic tongue with automation features of the flow-injection system allows us to accurately characterize the Cu(2+) ion-biosorption process, through obtaining its breakthrough curves, and the profile of the Ca(2+) ion release. In parallel, fractions of the extract solution are analysed by spectroscopic techniques in order to validate the results obtained with the reported methodology. The sorption performance of grape stalks is also evaluated by means of well-established sorption models.

  2. 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…

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. [Study on species and valence state of heavy metals and deleterious elements of mineral medicine].

    PubMed

    Han, Xu; Luo, Jiao-yang; Liu, Qiu-tao; Li, Yan-jun; Xie, Yan-jun; Yang, Shi-hai; Yang, Mei-hua

    2015-12-01

    As an important part of traditional Chinese medicine (TCM), mineral medicine plays an irreplaceable role. However, little has been reported on its species and valence state of heavy metals and deleterious elements, and also the relevance to pharmacological effect and toxicology. The present paper, in a new perspective, summarized the determination of the species and valence state of heavy metals and deleterious elements in recent years, discussed the progress of the pharmacological effect and toxicology, and prospected for future study which might provide reference for mineral medicine.

  8. 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.

  9. Calculation of dose contributions of electron and charged heavy particles inside phantoms irradiated by monoenergetic neutron.

    PubMed

    Satoh, Daiki; Takahashi, Fumiaki; Endo, Akira; Ohmachi, Yasushi; Miyahara, Nobuyuki

    2008-09-01

    The radiation-transport code PHITS with an event generator mode has been applied to analyze energy depositions of electrons and charged heavy particles in two spherical phantoms and a voxel-based mouse phantom upon neutron irradiation. The calculations using the spherical phantoms quantitatively clarified the type and energy of charged particles which are released through interactions of neutrons with the phantom elements and contribute to the radiation dose. The relative contribution of electrons increased with an increase in the size of the phantom and with a decrease in the energy of the incident neutrons. Calculations with the voxel-based mouse phantom for 2.0-MeV neutron irradiation revealed that the doses to different locations inside the body are uniform, and that the energy is mainly deposited by recoil protons. The present study has demonstrated that analysis using PHITS can yield dose distributions that are accurate enough for RBE evaluation.

  10. Observations by electron microscopy of tracks of heavy particles in cellulose triacetate

    SciTech Connect

    Vareille, J.C.; Decossas, J.L.; Moliton, J.P.; Teyssier, J.L.; Delaunay, B.

    1982-07-01

    Tracks of heavy charged particles have been observed in cellulose acetate by conventional electron microscopy (100 kV) and by high voltage microscopy (1, 2 MV). The tracks are formed of successive islets following each other at distances of 70 to 150 A. With the evolution of the diameter of these zones is shown the existence of a highly perturbed cylindrical volume (diameter 400 A for the case of krypton) corresponding to regions in which free radicals have been created. The different techniques used do not allow observation of the latent track because of the complications of energetic phenomena: the electron beam current density being limited, the contrast is small and hence the resolution is restricted.

  11. Effects of model approximations for electron, hole, and photon transport in swift heavy ion tracks

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

    The event-by-event Monte Carlo code, TREKIS, was recently developed to describe excitation of the electron subsystems of solids in the nanometric vicinity of a trajectory of a nonrelativistic swift heavy ion (SHI) decelerated in the electronic stopping regime. The complex dielectric function (CDF) formalism was applied in the used cross sections to account for collective response of a matter to excitation. Using this model we investigate effects of the basic assumptions on the modeled kinetics of the electronic subsystem which ultimately determine parameters of an excited material in an SHI track. In particular, (a) effects of different momentum dependencies of the CDF on scattering of projectiles on the electron subsystem are investigated. The 'effective one-band' approximation for target electrons produces good coincidence of the calculated electron mean free paths with those obtained in experiments in metals. (b) Effects of collective response of a lattice appeared to dominate in randomization of electron motion. We study how sensitive these effects are to the target temperature. We also compare results of applications of different model forms of (quasi-) elastic cross sections in simulations of the ion track kinetics, e.g. those calculated taking into account optical phonons in the CDF form vs. Mott's atomic cross sections. (c) It is demonstrated that the kinetics of valence holes significantly affects redistribution of the excess electronic energy in the vicinity of an SHI trajectory as well as its conversion into lattice excitation in dielectrics and semiconductors. (d) It is also shown that induced transport of photons originated from radiative decay of core holes brings the excess energy faster and farther away from the track core, however, the amount of this energy is relatively small.

  12. Giotto data analysis: Electron plasma and heavy ion composition measurements at Comet Halley

    NASA Technical Reports Server (NTRS)

    Lin, Robert P.

    1992-01-01

    This investigation involved the analysis of electron plasma and heavy ion composition measurements made by the COPERNIC (COmplete Positive ion, Electron, and Ram Negative Ion measurements near Comet Halley) plasma experiment during the close fly-by of Halley by the European Space Agency's Giotto spacecraft. The experiment provided measurements of the full 3-dimensional distribution of 10 eV-30 keV electrons, and mass analysis of cold cometary ions from 10-210 amu. The analysis of the COPERNIC data has yielded some remarkable results, including: The discovery of negatively charged ions in the inner coma; the discovery of far heavier (mass is greater than 50 amu) ions than predicted, dominated by complex molecular ions made up of C, H, O, and N; the discovery of an adiabatic heating effect on electrons from the compression of the solar wind plasma; the identification of several organic and sulfur bearing ions; and the discovery of a new 'mystery region' where electrons are accelerated to high energies. These discoveries were in addition to the detailed analysis of 'expected' features at Comet Halley. Although this grant has expired, analysis continues on the data at a low (unfunded) level, and it is expected that more significant results will be obtained. A bibliography of the papers resulting from this research is attached, and a copy of each paper is included.

  13. Cosmic ray electron and positron excesses from a fourth generation heavy Majorana neutrino

    SciTech Connect

    Masina, Isabella; Sannino, Francesco E-mail: sannino@cp3-origins.net

    2011-08-01

    Unexpected features in the energy spectra of cosmic rays electrons and positrons have been recently observed by PAMELA and Fermi-LAT satellite experiments, opening to the exciting possibility of an indirect manifestation of new physics. A TeV-scale fourth lepton family is a natural extension of the Standard Model leptonic sector (also linked to the hierarchy problem in Minimal Walking Technicolor models). The heavy Majorana neutrino of this setup mixes with Standard Model charged leptons through a weak charged current interaction. Here, we first study analytically the energy spectrum of the electrons and positrons originated in the heavy Majorana neutrino decay modes, also including polarization effects. We then compare the prediction of this model with the experimental data, exploiting both the standard direct method and our recently proposed Sum Rules method. We find that the decay modes involving the tau and/or the muon charged leptons as primary decay products fit well the PAMELA and Fermi-LAT lepton excesses while there is tension with respect to the antiproton to proton fraction constrained by PAMELA.

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

    PubMed

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

    2009-10-01

    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.

  15. 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.

  16. 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).

  17. 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%.

  18. 3D glasma initial state for relativistic heavy ion collisions

    NASA Astrophysics Data System (ADS)

    Schenke, Björn; Schlichting, Sören

    2016-10-01

    We extend the impact-parameter-dependent Glasma model to three dimensions using explicit small-x evolution of the two incoming nuclear gluon distributions. We compute rapidity distributions of produced gluons and the early-time energy momentum tensor as a function of space-time rapidity and transverse coordinates. We study rapidity correlations and fluctuations of the initial geometry and multiplicity distributions and make comparisons to existing models for the three-dimensional initial state.

  19. Electronic states of coupled graphene nanoribbons

    NASA Astrophysics Data System (ADS)

    Hashimoto, Futo; Mori, Nobuya; Kubo, Osamu; Katayama, Mitsuhiro

    2017-04-01

    Electronic states of laterally coupled graphene nanoribbons (GNRs) have been calculated within a nearest-neighbor tight-binding approximation with varying inter-GNR coupling strength γ from γ = 0 to t (intra-GNR transfer integral). For a coupled zigzag-edge GNR array, both almost flat bands and anisotropic Dirac cones appear near the Fermi level. For a coupled armchair-edge GNR array with a ribbon width N = 3n or 3n + 1, the system is semiconducting with a finite bandgap at γ = 0, which decreases as γ increases. For N = 3n, it becomes metallic with a zero bandgap only at γ = t. On the other hand, for N = 3n + 1, it becomes metallic when γ ≥ t/2. At γ = t/2, a peculiar energy dispersion emerges; the energy dispersion is parabolic perpendicular to the GNR axis and linear parallel to the GNR axis. When N = 3n + 2, the system is always metallic regardless of γ.

  20. Electronic excited states of CO/sub 2/: An electron impact investigation

    SciTech Connect

    McDiarmid, R.; Doering, J.P.

    1984-01-15

    The electronic excited states of CO/sub 2/ were restudied by variable incident energy, variable angle electron impact spectroscopy. In this study, valence states of mixed configurations were distinguished from pure Rydberg states. Our results are incompatible with the theoretical description of CO/sub 2/, in which only two valence singlet states are located.

  1. Importance of electronic state of two-dimensional electron gas for electron injection process in nano-electronic devices

    NASA Astrophysics Data System (ADS)

    Muraguchi, M.; Endoh, T.; Takada, Y.; Sakurai, Y.; Nomura, S.; Shiraishi, K.; Ikeda, M.; Makihara, K.; Miyazaki, S.; Shigeta, Y.

    2010-09-01

    We report the unexpected temperature dependence of electron tunneling from the two-dimensional electron gas (2DEG) to the Si-dot in a Si-dots floating gate metal-oxide-semiconductor (MOS) capacitor. We indicate that this temperature dependence of the electron tunneling cannot be explained by the conventional one-dimensional tunneling model, and show that it is necessary for a new model which includes the geometrical factor of the system. To extract a mechanism of the electron injection process from the 2DEG to the nano-structure, we have employed the numerical simulation, which includes both the geometrical condition of the system and the experimental setup. We suggest in our new tunneling model that the main contribution to the electron tunneling is induced by the wave-packet-like state of the electron below the Si-dots. We successfully show that the temperature dependence of the electron injection voltage in the Si-dots floating gate MOS capacitor fits our model. This indicates that the spatial distribution of electron density in the two-dimensional electron gas would play a crucial role in the electron tunneling.

  2. Minimal parametrization of an n -electron state

    NASA Astrophysics Data System (ADS)

    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(m4) matrix elements. The eigenstates of this Hamiltonian—i.e., the full-CI states Ψ —depend, however, on the usually much larger set of N=O(mn) parameters. One can, nevertheless, write a full-CI state as Ψ=eSΦ with Φ 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 Ψ=eTΦ 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 Φ is concerned. (c) There are solutions of the CCGSD equations, for which some elements of T becomes negative infinite, and eT 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 Φ a single Slater determinant, using a perturbation expansion, that CCGSD cannot be exact. This required a reformulation of the CCGSD operator eT to an equivalent exponential form eR , with R similar to the S of TCC theory, but with constraints on the cluster amplitudes, such that these depend on d parameters only. The CCGSD ansatz

  3. Ionization and Electron Emission of Heavy Ion - Collisions: the Argon-Krypton Collision System.

    NASA Astrophysics Data System (ADS)

    Zarcone, Michael Joseph, Jr.

    The Ar-Kr collision system has been studied by examining the charge states of the scattered ions together with the energies of the emitted electrons. The charge state data show that there are increases in the average scattered charge state at distances of closest approach that correspond well with internuclear distances for which the molecular orbital model^1 predicts electron promotions of krypton and argon electrons to occur. The electron data show a well resolved Auger peak between 150 -200 eV superimposed on an exponentially decreasing background of continuum electrons. Doppler shifts identify the Auger peak as originating from the argon collision partner. Ion -electron coincidence experiments exhibit the same peak and link it to a specific distance of closest approach. The threshold for this L-Auger electron production falls between 0.2 and 0.3 a.u., agreeing well with molecular orbital predictions. ftn^1Fano U. and W. Lichten, Phys. Rev. Lett., 14, 627 1965.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  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. Harms to Adults from Others' Heavy Drinking in Five Indian States

    PubMed Central

    Esser, Marissa B.; Gururaj, Gopalkrishna; Rao, Girish N.; Jernigan, David H.; Murthy, Pratima; Jayarajan, Deepak; Lakshmanan, S.; Benegal, Vivek; Babu, G. Krishna; Dutta, Sanjiba; Mehta, Ritambhara; Mishra, Kaushik; Tambe, Muralidhar

    2016-01-01

    Aims The aims of this study were to assess a wide range of alcohol-related harms from known heavy drinkers in Indian respondents' lives, and to assess respondents' characteristics and drinking patterns associated with reporting these harms. Methods Household interviews were administered in five Indian states from October 2011 to May 2012. For the secondary data analyses in this study, participants were Indians, ages 15–70, who self-reported having a heavy drinker in their lives (n = 5,375). We assessed the proportion of respondents reporting seventeen types of alcohol-related harms from a heavy drinker. Results Approximately 83% of respondents reported at least one alcohol-related harm from a heavy drinker in their lives. Twenty-five percent of respondents reported physical harm, 6% reported sexual harm and 50% reported emotional harm or neglect. Controlling for other factors, being in the upper income quartiles was associated with reporting ≥5 harm types. Among females, being age 25–39 and married/cohabitating predicted reporting ≥5 harm types, while among males, being age 25–39 or age 40–70 and living in a rural area increased the odds. Among females, binge drinkers had 46% lower odds of reporting ≥5 harm types than abstainers; among males, binge drinkers had 54% greater odds. Conclusion Regardless of respondents' own drinking pattern, a substantial proportion of respondents reported experiencing a range of harms from a known heavy drinker; interventions are needed to reduce these harms. PMID:26884508

  10. Triplet excited states of cyclic disulfides and related compounds: electronic structures, geometries, energies, and decay.

    PubMed

    Ginagunta, Saroja; Bucher, Götz

    2011-02-03

    We have performed a computational study on the properties of a series of heterocycles bearing two adjacent heteroatoms, focusing on the structures and electronic properties of their first excited triplet states. If the heteroatoms are both heavy chalcogens (S, Se, or Te) or isoelectronic species, then the lowest excited triplet state usually has (π*, σ*) character. The triplet energies are fairly low (30-50 kcal mol(-1)). The (π*, σ*) triplet states are characterized by a significantly lengthened bond between the two heteroatoms. Thus, in 1,2-dithiolane (1b), the S-S bond length is calculated to be 2.088 Å in the singlet ground state and 2.568 Å in the first triplet excited state. The spin density is predicted to be localized almost exclusively on the sulfur atoms. Replacing one heavy chalcogen atom by an oxygen atom or an NR group results in a significant destabilization of the (π*, σ*) triplet excited state, which then no longer is lower in energy than an open-chain biradical. The size of the heterocyclic ring also contributes to the stability of the (π*, σ*) triplet state, with five-membered rings being more favorable than six-membered rings. Benzoannulation, finally, usually lowers the energy of the (π*, σ*) triplet excited states. If one of the heteroatoms is an oxygen or nitrogen atom, however, the corresponding lowest triplet states are better described as σ,π-biradicals.

  11. Kinetics of Electrons from Plasma Discharge in a Latent Track Region Induced by Swift Heavy ION Irradiation

    NASA Astrophysics Data System (ADS)

    Minárik, Stanislav

    2015-08-01

    While passing swift heavy ion through a material structure, it produces a region of radiation affected material which is known as a "latent track". Scattering motions of electrons interacting with a swift heavy ion are dominant in the latent track region. These phenomena include the electron impurity and phonon scattering processes modified by the interaction with the ion projectile as well as the Coulomb scattering between two electrons. In this paper, we provide detailed derivation of a 3D Boltzmann scattering equation for the description of the relative scattering motion of such electrons. Phase-space distribution function for this non-equilibrioum system of scattering electrons can be found by the solution of mentioned equation.

  12. Electronic sputtering of thin SiO 2 films by MeV heavy ions

    NASA Astrophysics Data System (ADS)

    Arnoldbik, W. M.; Tomozeiu, N.; Habraken, F. H. P. M.

    2003-04-01

    The rate of removal of material from SiO 2 as a result of heavy ion irradiation, with energies in which energy loss via excitation and ionization of the solid predominates, depends strongly on the stopping power and angle of incidence of the incoming ions. There appears to be a threshold stopping power for SiO 2 of 500 eV/(10 15 at/cm 2) (or 3.5 keV/nm). This electronic sputter yield has been found to reach values as large as 10 4 atoms/incoming ion for 66 MeV Ag ions at an angle of incidence of 7° with the plane of the surface. Strikingly, the electronic sputter yield is very small for thin SiO 2 layers of a thickness ⩽1 nm when grown on c-Si, but it is appreciable for such layers deposited on the insulator silicon nitride. The data are discussed in the light of existing models for electronic sputtering invoking also models for potential sputtering of SiO 2 by low-energy, highly charged ions.

  13. 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.

  14. Status report on electron cyclotron resonance ion sources at the Heavy Ion Medical Accelerator in Chiba

    NASA Astrophysics Data System (ADS)

    Kitagawa, A.; Muramatsu, M.; Sekiguchi, M.; Yamada, S.; Jincho, K.; Okada, T.; Yamamoto, M.; Hattori, T.; Biri, S.; Baskaran, R.; Sakata, T.; Sawada, K.; Uno, K.

    2000-02-01

    The Heavy Ion Medical Accelerator in Chiba at the National Institute of Radiological Sciences (NIRS) is not only dedicated to cancer therapy, it is also utilized with various ion species for basic experiments of biomedical science, physics, chemistry, etc. Two electron cyclotron resonance (ECR) ion sources are installed for production of gaseous ions. One of them, the NIRS-ECR, is a 10 GHz ECR ion source, and is mainly operated to produce C4+ ions for daily clinical treatment. This source realizes good reproducibility and reliability and it is easily operated. The other source, the NIRS-HEC, is an 18 GHz ECR ion source that is expected to produce heavier ion species. The output ion currents of the NIRS-ECR and the NIRS-HEC are 430e μA for C4+ and 1.1e mA for Ar8+, respectively.

  15. Interface between heavy fermions and normal electrons investigated by spatially resolved nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Yamanaka, Takayoshi; Shimozawa, Masaaki; Endo, Ryota; Mizukami, Yuta; Shishido, Hiroaki; Terashima, Takahito; Shibauchi, Takasada; Matsuda, Yuji; Ishida, Kenji

    2015-12-01

    We have studied the superlattices with alternating block layers (BLs) of heavy-fermion superconductor CeCoIn5 and conventional-metal YbCoIn5 by site-selective nuclear magnetic resonance spectroscopy, which uniquely offers spatially resolved dynamical magnetic information. We find that the presence of antiferromagnetic fluctuations is confined to the Ce BLs, indicating that magnetic degrees of freedom of f electrons are quenched inside the Yb BLs. Contrary to simple expectations that the two dimensionalization enhances fluctuations, we observe that antiferromagnetic fluctuations are rapidly suppressed with decreasing Ce BL thickness. Moreover, the suppression is more prominent near the interfaces between the BLs. These results imply significant effects of local inversion symmetry breaking at the interfaces.

  16. Enhancement stabilization of heavy metals (Zn, Pb, Cr and Cu) during vermifiltration of liquid-state sludge.

    PubMed

    Yang, Jian; Zhao, Chunhui; Xing, Meiyan; Lin, Yanan

    2013-10-01

    This paper illustrated the potential effect of earthworms on heavy metal stabilization after vermifiltration of liquid-state sludge. Significant enhancement of organics degradation in sludge caused an increase of heavy metal concentrations in VF effluent sludge. However, the analysis of heavy metal chemical speciation indicated earthworms made unstable fractions of heavy metals transformed into stable fractions. Further investigation using principal component analysis revealed that transformations of heavy metal fractions were mainly due to the changes in sludge physico-chemical properties of pH, soluble chemical oxygen demand and available phosphorus. The bioassay of earthworms indicated that only zinc was accumulated by earthworms because the unstable fraction was its main chemical speciation. Furthermore, risk analysis demonstrated that earthworm activities weakened heavy metal risk due to the formation of stable fractions although their total concentrations increased. These results indicated that earthworms in vermifilter had a positive role in stabilizing heavy metals in sewage sludge.

  17. 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.

  18. From femtonova to supernova: Heavy-ion collisions and 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.

    2016-05-01

    Calculations using astrophysical equations of state at low densities comparable to that of the neutrino emission surface in supernovae and accretion disks are confronted with experimental results from heavy ion collisions. An extension of previous work shows that it is important to include all of the measured experimental data to draw conclusions about the astrophysical equation of state. Armed with this information, the calculations of the astrophysical equation of state are significantly constrained. Predictions of temperatures and densities sampled in black hole accretion disks are compared to those sampled in the experimental data.

  19. 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.

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

    DOE PAGES

    Pratt, Scott; Sorensen, Paul; Sangaline, Evan; ...

    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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Study of transients in the formation of heavy-current nanosecond electron beams

    NASA Astrophysics Data System (ADS)

    Pegel', I. V.

    1996-12-01

    Results are presented from experimental and numerical studies of the spatial and temporal microstructure of a relativistic heavy-current electron beam of nanosecond duration. The beam is formed in a magnetically insulated coaxial diode with an edge-emitting cathode. Microcurrent oscillations and azimuthal nonuniformity of the beam are seen, the scale of the latter depending on the maximum cyclotron radius of the electrons. Two- and three-dimensional numerical calculations performed by the macroparticle method show that space-charge oscillations near the cathode produce these phenomena even in the case of a uniform emission surface. It is shown that the increase in the full current of the beam that occurs during the pulse in a weak magnetic field is connected with the gradual propagation of emission to the cylindrical outside surface of the cathode. A study is made of the effect of the discreteness of the emission surface on the impedance and current of the vacuum diode. The linear increase seen in current during the pulse with a small number of emission centers is attributed to an increase in their size as a result of expansion of the cathode plasma.

  6. Analysis of relativistic effects in electron-impact excitation of SP transitions in heavy atoms.

    NASA Astrophysics Data System (ADS)

    Andersen, Nils; Bartschat, Klaus

    2002-05-01

    While elastic electron scattering from heavy atoms is known to be strongly affected by relativistic effects such as Mott scattering, it seems surprising that several sets of recent experimental results for electron-impact excitation of the (6s)^2S_1/2 (6p)^2P_1/2,3/2 transition [1,2] in Cs could be well reproduced by a non-relativistic ``convergent close-coupling'' (CCC) model. It is, therefore, desirable to analyze the sensitivity of currently measured observables to relativistic effects, as well as to develop new prescriptions to enhance the potential for experimental tests of sophisticated collision theories. Using the above transition as an example, we developed a new formulation to describe the collision process and the experimental investigations, based on the concept of ``generalized Stokes parameters'' [3]. [1] V. Karaganov, P.J.O. Teubner, and M.J. Brunger, in Correlations, Polarization, and Ionization in Atomic Systems, AIP (New York, 2000). [2] G. Baum and I. Bray (2002), private communication. [3] N. Andersen and K. Bartschat, Polarization, Alignment, and Orientation in Atomic Collisions, Springer (New York, 2000).

  7. Assessment of an Electronic Intervention in Young Women with Heavy Menstrual Bleeding.

    PubMed

    Dietrich, Jennifer E; Yee, Donald L; Santos, Xiomara M; Bercaw-Pratt, Jennifer L; Kurkowski, Jennifer; Soni, Heather; Lee-Kim, Youngna J; Shah, Mona D; Mahoney, Donald; Srivaths, Lakshmi V

    2016-10-15

    STUDY OBJECTIVE, DESIGN, SETTING, PARTICIPANTS, INTERVENTIONS, AND MAIN OUTCOME MEASURES: Bleeding disorders (BD) occur in up to 50% of adolescents with heavy menstrual bleeding (HMB). This presents unique challenges to health care providers because of the complexity of treating the condition and such complexity can result in difficulty with patients understanding basic information about their condition, limit communication with medical providers, and patient compliance. The aim of the study was to use an electronic approach to enhance patient compliance with medications used to treat their HMB, and to provide educational access to adolescents with BD. This was a prospective cohort study involving patients in a Young Women's Bleeding Disorder Clinic at a single children's hospital. Subjects were given an iPod Touch (Apple Inc, Cupertino, CA) device (ITD), preloaded with the iPeriod (Winkpass Creations) application. Participants recorded information about their BD that they learned about on BD Web sites, and menses, and medications. Electronic and charted data were collected to monitor compliance with prescribed treatment regimens. All ITD allowed Wi-Fi access to allow teens to explore BD Web sites and knowledge was assessed.

  8. 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.

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

    DOE PAGES

    Fischer, W.; Gu, X.; Altinbas, Z.; ...

    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.

  10. Operational Head-on Beam-Beam Compensation with Electron Lenses in the Relativistic Heavy Ion Collider

    NASA Astrophysics Data System (ADS)

    Fischer, W.; Gu, X.; Altinbas, Z.; Costanzo, M.; Hock, J.; Liu, C.; Luo, Y.; Marusic, A.; Michnoff, R.; Miller, T. A.; Pikin, A. I.; Schoefer, V.; Thieberger, P.; White, S. M.

    2015-12-01

    Head-on beam-beam compensation has been implemented in the Relativistic Heavy Ion Collider 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. To date, the implemented compensation scheme approximately doubled the peak and average luminosities.

  11. On the electron whistler dispersion law in a cold plasma with light ions and heavy charged particulates

    SciTech Connect

    Lundin, B. V.; Krafft, C.

    2009-05-15

    The dispersion equation of electron whistler waves in a cold plasma with two light ions of comparable gyrofrequencies and heavy charged particulates is derived. It is valid in a very wide frequency range above the highest ion cutoff frequency when the wave frequency is essentially less than the electron plasma frequency. The derived electron whistler dispersion law is expressed through the relative contents of the two light ions and the electrons, as well as the characteristic frequencies of the magnetized plasma, as the lower hybrid resonance frequency, the two highest ion cutoff frequencies, the gyrofrequencies of the light ions, and the electron gyro- and plasma frequencies. The approximation of vanishingly small gyrofrequencies of the heavy ions permits to determine with a relevant accuracy the electron whistler dispersion law using the features of electron whistler spectrograms only. Estimates of the relative charge density of the light ions are obtained and the dispersion laws of the adjacent branches, i.e., the electron whistler waves and the so-called ion cyclotron whistlers are calculated. For the electron whistler waves, the presence of negative ions can be the origin of a manyfold increase in the lower cutoff frequency; a merging effect of the cutoff frequencies of the adjacent branches can also appear.

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

    DOE PAGES

    Luo, Yongkang; Chen, Hua; Dai, Jianhui; ...

    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

  13. 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

  14. 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.

  15. Heavy metal contamination of surface soil in electronic waste dismantling area: site investigation and source-apportionment analysis.

    PubMed

    Jinhui Li; Huabo Duan; Pixing Shi

    2011-07-01

    The dismantling and disposal of electronic waste (e-waste) in developing countries is causing increasing concern because of its impacts on the environment and risks to human health. Heavy-metal concentrations in the surface soils of Guiyu (Guangdong Province, China) were monitored to determine the status of heavy-metal contamination on e-waste dismantling area with a more than 20 years history. Two metalloids and nine metals were selected for investigation. This paper also attempts to compare the data among a variety of e-waste dismantling areas, after reviewing a number of heavy-metal contamination-related studies in such areas in China over the past decade. In addition, source apportionment of heavy metal in the surface soil of these areas has been analysed. Both the MSW open-burning sites probably contained invaluable e-waste and abandoned sites formerly involved in informal recycling activities are the new sources of soil-based environmental pollution in Guiyu. Although printed circuit board waste is thought to be the main source of heavy-metal emissions during e-waste processing, requirement is necessary to soundly manage the plastic separated from e-waste, which mostly contains heavy metals and other toxic substances.

  16. Reduction of heavy metals in residues from the dismantling of waste electrical and electronic equipment before incineration.

    PubMed

    Long, Yu-Yang; Feng, Yi-Jian; Cai, Si-Shi; Hu, Li-Fang; Shen, Dong-Sheng

    2014-05-15

    Residues disposal from the dismantling of waste electrical and electronic equipment are challenging because of the large waste volumes, degradation-resistance, low density and high heavy metal content. Incineration is advantageous for treating these residues but high heavy metal contents may exist in incinerator input and output streams. We have developed and studied a specialized heavy metal reduction process, which includes sieving and washing for treating residues before incineration. The preferable screen aperture for sieving was found to be 2.36mm (8 meshes) in this study; using this screen aperture resulted in the removal of approximately 47.2% Cu, 65.9% Zn, 26.5% Pb, 55.4% Ni and 58.8% Cd from the residues. Subsequent washing further reduces the heavy metal content in the residues larger than 2.36mm, with preferable conditions being 400rpm rotation speed, 5min washing duration and liquid-to-solid ratio of 25:1. The highest cumulative removal efficiencies of Cu, Zn, Pb, Ni and Cd after sieving and washing reached 81.1%, 61.4%, 75.8%, 97.2% and 72.7%, respectively. The combined sieving and washing process is environmentally friendly, can be used for the removal of heavy metals from the residues and has benefits in terms of heavy metal recycling.

  17. 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.

  18. Heavy quarkonium ππ transitions and a possible bb¯qq¯ state

    NASA Astrophysics Data System (ADS)

    Guo, F.-K.; Shen, P.-N.; Chiang, H.-C.; Ping, R.-G.

    2005-11-01

    ππ transitions of heavy quarkonia, especially the ϒ(3S)→ϒ(1S)ππ decay process, are revisited. In the framework of the Chiral Unitary Theory (ChUT), the S wave ππ final state interaction (FSI) is included. It is found that when an additional intermediate state with J=1 and I=1 is introduced, not only the ππ invariant mass spectrum and the cosθπ∗ distribution in the ϒ(3S)→ϒ(1S)ππ process can simultaneously be well explained, but also a consistent description for other bottomonia ππ transitions can be obtained. As a consequence, the mass and the width of the intermediate state are predicted. From the quark content analysis, this state should be a bb¯qq¯ state.

  19. 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.

  20. On the electron wavepacket dynamics of photoionizing states

    NASA Astrophysics Data System (ADS)

    Takatsuka, Kazuo

    2014-06-01

    To study electron wavepacket dynamics of photoionizing states in polyatomic molecules, we discuss two crucial issues to be overcome in the theory of molecular electronic wavepacket dynamics in an intense laser field (Takatsuka and Yonehara 2011 Phys. Chem. Chem. Phys. 13 4987). One is about the description of the ionization process from electronically excited states composed of many multiply excited configuration-state functions. The other is how to reconstruct the electronic states remaining in the molecular site while electrons are flowing out of the molecular bounds. These are both critical to extend the realm of the theories of electron dynamics based on the so-called expansion (algebraic) method in terms of basis functions. To calculate the photoionization amplitude and thereby to estimate the time-dependent amount of electron loss from a molecule, we extract the electron flux (probability current density) from the electron wavepackets without use of scattering theory. This is justified by the success of the recent works by Bandrauk’s group for attosecond photoionization dynamics from the hydrogen molecule ion, who performed numerical integration of the relevant Schrödinger equation (Yuan et al 2013 J. Chem. Phys. 138 134316). A key feature in the present study, on the other hand, is to calculate the electron flux in terms of complex-valued NOs, which arise from the complex electronic wavepackets. Through the change of these NOs, we reconstruct the involved electronic configurations during the flow of electrons out of molecular regions. These repopulated electronic wavefunctions are (non-adiabatically) evolved in time under laser fields.

  1. 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.

  2. 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.

  3. Two state electron model for geminate recombination of electron-ion pairs in liquid isooctane

    NASA Astrophysics Data System (ADS)

    Lukin, L. V.; Yakovlev, B. S.

    2011-04-01

    Recombination kinetics of geminate electron-ion pairs is considered in the framework of the two state model for electron transport in liquid hydrocarbons. It is shown that the model well reproduces recent experimental data on the subpicosecond geminate recombination obtained in liquid isooctane. The life time of electrons in a localized state in isooctane is estimated to lie in the range between 0.14 ps and 0.57 ps at room temperature.

  4. Electron-spin-resonance investigation of the heavy-fermion compound Ce(Cu1-xNix)2Ge2

    NASA Astrophysics Data System (ADS)

    Krug von Nidda, H.-A.; Schütz, A.; Heil, M.; Elschner, B.; Loidl, A.

    1998-06-01

    The heavy-fermion compound Ce(Cu1-xNix)2Ge2 is investigated by Gd3+ electron spin resonance (ESR) within the whole concentration range (0<=x<=1). The Kondo-lattice system exhibits an alloying-induced transition from an antiferromagnetically ordered heavy-fermion ground state (x=0) to pure Kondo-like behavior with strongly enhanced effective masses (x=1). The temperature dependence of the ESR linewidth ΔH allows one to distinguish between the different ground states. The nature of the magnetic order changes significantly from concentrations x<~0.5 to x>0.5. The ESR data provide some further experimental evidence for a transition from a local-moment type (x<0.5) to some kind of itinerant heavy-fermion band magnetism (0.5

  5. Single-sheet identification method of heavy charged particles using solid state nuclear track detectors

    NASA Astrophysics Data System (ADS)

    Zaki, M. F.; Abdel-Naby, A.; Morsy, A. Ahmed

    2007-08-01

    The theoretical and experimental investigations of the penetration of charged particles in matter played a very important role in the development of modern physics. Solid state nuclear track detectors have become one of the most important tools for many branches of science and technology. An attempt has been made to examine the suitability of the single-sheet particle identification technique in CR-39 and CN-85 polycarbonate by plotting track cone length vs. residual range for different heavy ions in these detectors. So, the maximum etchable ranges of heavy ions such as ^{93}Nb, ^{86}Kr and ^{4}He in CR-39 and ^{4}He and ^{132}Xe in CN-85 polycarbonate have been determined. The ranges of these ions in these detectors have also been computed theoretically using the Henke-Benton program. A reasonably good agreement has been observed between the experimentally and theoretically computed values.

  6. Geochronology and heavy metal flux to Guanabara Bay, Rio de Janeiro state: a preliminary study.

    PubMed

    Baptista Neto, José A; Peixoto, Tomás C S; Smith, Bernard J; McAlister, John J; Patchineelam, Soraya M; Patchineelam, Sambasiva R; Fonseca, Estefan M

    2013-01-01

    Guanabara Bay, located in Rio de Janeiro state. It is surrounded by the second most important metropolitan area of the country. Over recent decades, land disturbance and urbanization in the surrounding area has significantly increased sediment input to the bay and had a negative effect on its overall environmental. This is especially related to high volumes of untreated sewage and industrial effluents. This study evaluates the history of this human impact through detailed examination of a sediment core taken from the northern portion of Guanabara Bay. A geochronology is established using ²¹⁰Pb dating and related to organic carbon and heavy metal fluxes to the sediments. This gave a calculated net average sedimentation rate for the core of 0.67 cm.year⁻¹. The organic carbon and heavy metals flux started to increase at the beginning of the last century and the highest values was observed in the top of the cores.

  7. 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

  8. Timekeeping with electron spin states in diamond

    NASA Astrophysics Data System (ADS)

    Hodges, J. S.; Yao, N. Y.; Maclaurin, D.; Rastogi, C.; Lukin, M. D.; Englund, D.

    2013-03-01

    Frequency standards based on atomic states, such as Rb or Cs vapors, or single-trapped ions, are the most precise measures of time. Here we propose and analyze a precision oscillator approach based upon spins in a solid-state system, in particular, the nitrogen-vacancy defect in single-crystal diamond. We show that this system can have stability approaching portable atomic standards and is readily incorporable as a chip-scale device. Using a pulsed spin-echo technique, we anticipate an Allan deviation of σy=10-7τ-1/2 limited by thermally-induced strain variations; in the absence of such thermal fluctuations, the system is limited by spin dephasing and harbors an Allan deviation nearing ˜10-12τ-1/2. Potential improvements based upon advanced diamond material processing, temperature stabilization, and nanophotonic engineering are discussed.

  9. {sup 209}Bi NMR in heavy-electron system YbBiPt

    SciTech Connect

    Reyes, A.P.; Le, L.P.; Heffner, R.H.; Ahrens, E.T.; Fisk, Z.; Canfield, P.C.

    1994-06-01

    Bismuth NMR Knight shift and spin lattice relaxation rate 1/T{sub 1} are reported between 35--325K in the low-carrier heavy fermion system YbBiPt. The Knight shift is strongly temperature dependent and negative. Its temperature dependence tracks the bulk susceptibility with a hyperfine coupling constant A{sub hf} = {minus}7.89 kOe/{mu}B. At low temperatures 1/T{sub 1} exhibits a dramatic increase, such that the average 4f spin correlation time {tau}{sub f} shows a crossover behavior at about 75K. The rate 1/{tau}{sub f} is proportional to temperature, but with a different proportionality constant above and below about 75K. The linear temperature dependence is consistent with non-interacting 4f local moments which are relaxed via Korringa-type scattering with the conduction electrons. Below 75K, we infer that the reduced thermal excitation of a higher crystal-field multiplet is responsible for the dramatic decrease in the rate of 4f relaxation.

  10. 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.

  11. Determination of effective atomic number and electron density of heavy metal oxide glasses

    NASA Astrophysics Data System (ADS)

    Ali, A. M.; El-Khayatt, A. M.; Akkurt, I.

    2016-03-01

    The effective atomic number (Zeff) and effective electron density (Neff) of eight heavy metal oxide (HMO) glasses have been determined using the Monte Carlo simulation code MCNP for the energy range of 10 keV-10 MeV. The interpolation method was employed to extract Zeff and Neff values from the simulation and that calculated with the help of XCOM program. Comparisons are also made with predictions from the Auto-Zeff software in the same energy region. Wherever possible, the simulated values of Zeff and Neff are compared with experimental data. In general, a very good agreement was noticed. It was found that the Zeff and Neff vary with photon energy and do not have extended intermediate regions where Compton scattering is truly dominating; only dips slightly above ∼1.5 MeV were recorded. Zeff and Neff are found to increase with PbO and Bi2O3 contents. It was found that the Zeff value rather than the Neff value is a better indicator for PbO and/or Bi2O3 contents.

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

    DOE PAGES

    Tokiwa, Yoshifumi; Piening, Boy; Jeevan, Hirale S.; ...

    2016-09-09

    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 Kelvin. However, usage of the gas has been increasingly difficult because of the current world-wide 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.more » 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. Lastly, this study opens new possibilities of using itinerant magnetic moments for cryogen-free refrigeration.« less

  13. 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

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

    NASA Astrophysics Data System (ADS)

    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.

    2015-12-01

    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.

  15. 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

    2015-12-02

    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.

  16. 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

    2014-08-08

    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.

  17. Electronic states of the diatomic antimony fluoride (SbF)

    NASA Astrophysics Data System (ADS)

    Latifzadeh, Lida; Balasubramanian, K.

    1996-07-01

    The potential energy curves of 21 electronic states of SbF and spectroscopic properties of bound states among these have been computed using the complete active space self-consistent field (CASSCF) followed by first- and second-order configuration interaction (FOCI, SOCI) and multireference singles and doubles configuration interaction (MRSDCI) methods. The computed results are in good agreement with the observed values for six states, while the properties of four other states have been computed which are yet to be observed.

  18. 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.

  19. Electron states and electron Raman scattering in semiconductor step-quantum well: Electric field effect

    NASA Astrophysics Data System (ADS)

    Betancourt-Riera, Ri.; Betancourt-Riera, Re.; Ferrer-Moreno, L. A.; Jalil, J. M. Nieto

    2017-04-01

    In this work we determine and show the expressions of the electron states of a step-quantum well with the presence of an external electric field, developed in a GaAs / AlGaAs matrix. The electron states are obtained using the envelope function approximation. In this work it is only necessary to consider a single conduction band, which due to the confinement is divided into a subband system, with T = 0K . Expressions for the electron states and the differential cross-section for an intraband electron Raman scattering process of are presented, the net Raman gain is also calculated. In addition, the interpretation of the singularities found in the emission or excitation spectra is given, since several dispersion configurations are discussed. Furthermore, the effects of an electric field on the electron states and on the differential cross section are studied.

  20. Non-universal bound states of two identical heavy fermions and one light particle

    NASA Astrophysics Data System (ADS)

    Safavi, Arghavan; Rittenhouse, Seth; Blume, Dorte; Sadeghpour, Hossein

    2013-05-01

    We study a system of two identical heavy fermions of mass M and light particle of mass m. The interspecies interaction is modeled using a short-range two-body potential with positive s-wave scattering length. We impose a short-range boundary condition on the logarithmic derivative of the hyperradial wavefunction and show that, in the regime where Efimov states are absent, a non-universal three-body state ``cuts through'' the universal three-body states previously described by Kartavtsev and Malykh [O. I. Kartavtsev and A. V. Malykh, J. Phys. B 40, 1429 (2007)]. We study the effect of the non-universal state on the behavior of the universal states and use a simple quantum defect theory, utilizing hyperspherical coordinates, to explain the existence of the non-universal state. An empirical two-state model is employed to quantify the coupling of the non-universal state to the universal states. This work was supported by NSF through a grant for the Institute for Theoretical Atomic, Molecular and Optical Physics at Harvard University and Smithsonian Astrophysical Observatory and through grant PHY-1205443.

  1. 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.

  2. A theoretical study of low-lying electronic states of aminonitrene, phosphinonitrene, and phosphinocarbene

    NASA Astrophysics Data System (ADS)

    Hoffmann, Mark R.; Kuhler, Kathleen

    1991-06-01

    The recently formulated multiconfiguration-based unitary coupled electron pair approximation (UCEPA) is compared with multireference configuration interaction (MR-CISD) calculations, including all single and double excitations, for the molecules in this study. The electronic states of the molecules in this study are not only of experimental interest, but represent a challenge to any formalism to accurately predict the energy separations of the low-lying electronic states. The equilibrium geometries and fundamental vibrational frequencies of the three lowest electronic states (i.e., 1A1, 3A`, and 1A`) of aminonitrene H2N2, and phosphinonitrene, H2PN, have been determined using a split-valence basis with polarization functions on the heavy atoms and a small complete active space self-consistent-field (CASSCF) description of the active space. Both MR-CISD and UCEPA calculations have been performed at the equilibrium structures using larger basis sets to accurately determine the relative energetics of the electronic states. The equilibrium geometries and vibrational frequencies of the two lowest electronic states (i.e., 1A' and 3A`) of phosphinocarbene, H2PCH, have been determined using a larger than double zeta basis set, augmented with polarization and diffuse functions, and a CASSCF description of the active space. Both MR-CISD and UCEPA calculations were performed on the equilibrium structures and predict that the singlet lies between 10.4 and 11.8 kcal/mol lower in energy than the triplet. The use of a generalized valence bond (GVB) reference function within UCEPA is introduced and is shown to be a useful approximation.

  3. Electron-Electron Interaction in Ion-Atom Collisions Studied by Projectile State-Resolved Auger Electron Spectroscopy.

    NASA Astrophysics Data System (ADS)

    Lee, Do-Hyung

    1990-01-01

    This dissertation addresses the problem of dynamic electron-electron interactions in fast ion-atom collisions using projectile Auger electron spectroscopy. The study was carried out by measuring high-resolution projectile KLL Auger electron spectra as a function of projectile energy for the various collision systems of 0.25-2 MeV/u O^{q+} and F^ {q+} incident on H_2 and He targets. The electrons were detected in the beam direction, where the kinematic broadening is minimized. A zero-degree tandem electron spectrometer system was developed and showed the versatility of zero-degree measurements of collisionally-produced atomic states. The zero-degree binary encounter electrons (BEe), quasifree target electrons ionized by the projectiles in head-on collisions, were observed as a strong background in the KLL Auger electron spectrum. They were studied by treating the target ionization as 180^circ Rutherford elastic scattering in the projectile frame, and resulted in a validity test of the impulse approximation (IA) and a way to determine the spectrometer efficiency. An anomalous q-dependence, in which the zero-degree BEe yields increase with decreasing projectile charge state (q), was observed. State-resolved KLL Auger cross sections were determined by using the BEe normalization and thus the cross sections of the electron -electron interactions such as resonant transfer-excitation (RTE), electron-electron excitation (eeE), and electron -electron ionization (eeI) were determined. Projectile 2l capture with 1s to 2p excitation by the captured target electron was observed as an RTE process with Li-like and He-like projectiles and the measured RTEA (RTE followed by Auger decay) cross sections showed good agreement with an RTE-IA treatment and RTE alignment theory. Projectile 1s to 2p excitation by a target electron was observed an an eeE process with Li-like projectiles. Projectile 1s ionization by a target electron was observed as an eeI process with Be-like projectiles

  4. 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.

  5. Effects of final-state interaction and screening on strange and heavy quark production

    SciTech Connect

    Wong, Cheuk-Yin; Chatterjee, L. ||

    1996-10-01

    Final-state interaction and screening have a great influence on {ital q{anti q}} production cross sections, which are important quantities in many problems in quark-gluon plasma physics. They lead to an enhancement of the cross section for a {ital q{anti q}} color-singlet state and a suppression for a color-octet state. The effects are large near the production threshold. The presence of screening gives rise to resonances for {ital q{anti q}} production just above the threshold at specific plasma temperatures. These resonances, especially {ital c{anti c}} and {ital b{anti b}} resonances, may be utilized to search for the quark-gluon plasma by studying the temperature dependence of heavy-quark pair production just above the threshold.

  6. Modeling the QCD Equation of State in Relativistic Heavy Ion Collisions on BlueGene/L

    SciTech Connect

    Soltz, R; Grady, J; Hartouni, E P; Gupta, R; Vitev, I; Mottola, E; Petreczky, P; Karsch, F; Christ, N; Mawhinney, R; Bass, S; Mueller, B; Vranas, P; Levkova, L; Molnar, D; Teaney, D; De Tar, C; Toussaint, D; Sugar, R

    2006-04-10

    On 9,10 Feb 2006 a workshop was held at LLNL to discuss how a 10% allocation of the ASC BG/L supercomputer performing a finite temperature Lattice QCD (LQCD) calculation of the equation of state and non-equilibrium properties of the quark-gluon state of matter could lead to a breakthrough in our understanding of recent data from the Relativistic Heavy Ion Collider at Brookhaven National Lab. From this meeting and subsequent discussions we present a detailed plan for this calculation, including mechanisms for working in a secure computing environment and inserting the resulting equation of state into hydrodynamic transport models that will be compared directly to the RHIC data. We discuss expected benefits for DOE Office of Science research programs within the context of the NNSA mission.

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

    PubMed

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

    2012-10-23

    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 Cu(A) 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.

  8. Electronic Religion and the Separation of Church and State.

    ERIC Educational Resources Information Center

    Jackson, Gordon

    An examination of the rise of "electronic religion" (religious broadcasting on radio and television) in the United States and the movement's fusing of religious and political issues during the 1980 election year lends credibility to the argument that a clash between church and state is inherent in the political aspects of these…

  9. High Pressure NMR study of Knight Shift Anomaly on the heavy electron material CeRhIn5

    NASA Astrophysics Data System (ADS)

    Lin, Ching; Curro, Nicholas; Shirer, Kent; Crocker, John; Dioguardi, Adam; Shockley, Abigail; Lawson, Matthew

    2014-03-01

    We have measured the Nuclear Magnetic Resonance Knight Shift in the heavy f-electron material CeRhIn5 in order to investigate the coherence temperature T* as a function of pressure up to 2GPa. We find that the Knight Shift of both In(1) and In(2) sites changes significantly with pressure. Our results are consistent with the phase diagram proposed by Yang and Pines.

  10. Test of many-electron QED effects in the hyperfine splitting of heavy high-Z ions.

    PubMed

    Volotka, A V; Glazov, D A; Andreev, O V; Shabaev, V M; Tupitsyn, I I; Plunien, G

    2012-02-17

    A rigorous evaluation of the two-photon exchange corrections to the hyperfine structure in lithiumlike heavy ions is presented. As a result, the theoretical accuracy of the specific difference between the hyperfine splitting values of H- and Li-like Bi ions is significantly improved. This opens a possibility for the stringent test of the many-electron QED effects on a few percent level in the strongest electromagnetic field presently available in experiments.

  11. Electronic states in hybrid boron nitride and graphene structures

    NASA Astrophysics Data System (ADS)

    Zhao, M.; Huang, Y. H.; Ma, F.; Hu, T. W.; Xu, K. W.; Chu, Paul K.

    2013-08-01

    The energy bands and electronic states of hybrid boron nitride (BN) and graphene structures are studied by first principle calculations. The electronic states change from semi-metallic to insulating depending on the number of B and N atoms as well as domain symmetry. When there are unequal numbers of B and N atoms, mid-gap states usually appear around the Fermi level and the corresponding hybrid structure possesses magnetic and semi-metallic properties. However, when the numbers of B and N atoms are equal, a band gap exists indicative of a semiconducting or insulating nature which depends on the structural symmetry.

  12. Reverse quantum state engineering using electronic feedback loops

    NASA Astrophysics Data System (ADS)

    Kießlich, Gerold; Emary, Clive; Schaller, Gernot; Brandes, Tobias

    2012-12-01

    We propose an all-electronic technique to manipulate and control interacting quantum systems by unitary single-jump feedback conditioned on the outcome of a capacitively coupled electrometer and, in particular, a single-electron transistor. We provide a general scheme for stabilizing pure states in the quantum system and use an effective Hamiltonian method for the quantum master equation to elaborate on the nature of stabilizable states and the conditions under which state purification can be achieved. The state engineering within the quantum feedback scheme is shown to be linked with the solution of an inverse eigenvalue problem. Two applications of the feedback scheme are presented in detail: (i) stabilization of delocalized pure states in a single charge qubit and (ii) entanglement stabilization in two coupled charge qubits. In the latter example, we demonstrate the stabilization of a maximally entangled Bell state for certain detector positions and local feedback operations.

  13. 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.

  14. 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.

  15. 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

  16. Scanning electron microscope and statistical analysis of suspended heavy metal particles in San Luis Potosi, Mexico

    NASA Astrophysics Data System (ADS)

    Piña, A. Aragón; Villaseñor, G. Torres; Fernández, M. Monroy; Luszczewski Kudra, A.; Leyva Ramos, R.

    Three hundred samples of urban aerosol were collected in high-volume samplers from five urban locations situated near an important metallurgical plant in the city of San Luis Potosi, Mexico. Whole samples were analyzed by atomic absorption (AA) for Pb, Cd, As, Cu, Ni, Fe and Cr. One hundred eighty of these samples were subjected to X-ray microanalysis (EDS) coupled with a scanning electron microscope to classify individual particles according to their chemical or mineralogical composition. The principal component analysis (PCA) obtained from the bulk sample analysis, and X-ray microanalysis from individual particles, confirmed chemical associations among elements directly and indirectly. PCA from bulk assays made the most effective use of X-ray microanalysis to characterize major particle types. Some chemical associations would be difficult to detect using microanalysis, alone, for example, in anthropogenic complex phases. In this work, the combined use of microanalysis and statistical methods permitted identification of associations among elements. We observed an association of Pb-As-Cd and Fe-Mn among the samples. In a second order, Pb-Fe, Pb-Mn, Fe-As, Fe-Cd, Cd-Mn and As-Mn showed a lower association. Only Ni and Cu appeared unassociated with any other element analyzed by AA. We characterized the mineral phases by size range, morphology and chemical composition using SEM-EDS to obtain a compositional approach of anthropogenic phases and peculiar morphology and size. A high percentage of heavy metal particles smaller than 2 μm were detected.

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

    SciTech Connect

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

    2016-09-09

    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 Kelvin. However, usage of the gas has been increasingly difficult because of the current world-wide 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. Lastly, this study opens new possibilities of using itinerant magnetic moments for cryogen-free refrigeration.

  18. Anderson lattice with explicit Kondo coupling revisited: metamagnetism and the field-induced suppression of the heavy fermion state.

    PubMed

    Howczak, Olga; Spałek, Jozef

    2012-05-23

    We apply the extended (statistically consistent, SCA) Gutzwiller-type approach to the periodic Anderson model (PAM) in an applied magnetic field and in the strong-correlation limit. The finite-U corrections are included systematically by transforming the PAM into the form with the Kondo-type interaction and the residual hybridization, both appearing at the same time and on equal footing. This effective Hamiltonian represents the essence of our Anderson-Kondo lattice model. We show that in ferromagnetic phases the low-energy single-particle states are strongly affected by the presence of the applied magnetic field. We also find that for large values of hybridization strength the system enters the so-called locked heavy fermion state introduced earlier. In this state the chemical potential lies in the majority-spin hybridization gap and, as a consequence, the system evolution is insensitive to further increase of the applied field. However, for a sufficiently strong magnetic field, the system transforms from the locked state to the fully spin-polarized phase. This is accompanied by a metamagnetic transition, as well as by a drastic reduction of the effective mass of the quasiparticles. In particular, we observe no effective mass enhancement in the fully polarized state. The findings are in overall agreement with experimental results for the Ce compounds in high magnetic fields. The mass enhancement for the spin-minority electrons may also diminish with the increasing field, unlike for the quasiparticle states in a single narrow band in the same limit of strong correlations.

  19. State-to-state kinetics and transport properties of electronically excited N and O atoms

    NASA Astrophysics Data System (ADS)

    Istomin, V. A.; Kustova, E. V.

    2016-11-01

    A theoretical model of transport properties in electronically excited atomic gases in the state-to-state approach is developed. Different models for the collision diameters of atoms in excited states are discussed, and it is shown that the Slater-like models can be applied for the state-resolved transport coefficient calculations. The influence of collision diameters of N and O atoms with electronic degrees of freedom on the transport properties is evaluated. Different distributions on the electronic energy are considered for the calculation of transport coefficients. For the Boltzmann-like distributions at temperatures greater than 15000 K, an important effect of electronic excitation on the thermal conductivity and viscosity coefficients is found; the coefficients decrease significantly when many electronic states are taken into account. It is shown that under hypersonic reentry conditions the impact of collision diameters on the transport properties is not really important since the populations of high levels behind the shock waves are low.

  20. Theory of the electron spin resonance in the heavy fermion metal β-YbAlB4.

    PubMed

    Ramires, Aline; Coleman, Piers

    2014-03-21

    The heavy fermion metal β-YbAlB4 exhibits a bulk room temperature conduction electron spin resonance (ESR) signal which evolves into an Ising-anisotropic f-electron signal exhibiting hyperfine features at low temperatures. We develop a theory for this phenomenon based on the development of resonant scattering off a periodic array of Kondo centers. We show that the hyperfine structure arises from the scattering off the Yb atoms with nonzero nuclear spin, while the constancy of the ESR intensity is a consequence of the presence of crystal electric field excitations of the order of the hybridization strength.

  1. STEADY-STATE MODEL OF SOLAR WIND ELECTRONS REVISITED

    SciTech Connect

    Yoon, Peter H.; Kim, Sunjung; Choe, G. S.

    2015-10-20

    In a recent paper, Kim et al. put forth a steady-state model for the solar wind electrons. The model assumed local equilibrium between the halo electrons, characterized by an intermediate energy range, and the whistler-range fluctuations. The basic wave–particle interaction is assumed to be the cyclotron resonance. Similarly, it was assumed that a dynamical steady state is established between the highly energetic superhalo electrons and high-frequency Langmuir fluctuations. Comparisons with the measured solar wind electron velocity distribution function (VDF) during quiet times were also made, and reasonable agreements were obtained. In such a model, however, only the steady-state solution for the Fokker–Planck type of electron particle kinetic equation was considered. The present paper complements the previous analysis by considering both the steady-state particle and wave kinetic equations. It is shown that the model halo and superhalo electron VDFs, as well as the assumed wave intensity spectra for the whistler and Langmuir fluctuations, approximately satisfy the quasi-linear wave kinetic equations in an approximate sense, thus further validating the local equilibrium model constructed in the paper by Kim et al.

  2. 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

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

    SciTech Connect

    Abriata, Luciano A.; Alvarez-Paggi, Damian; Ledesma, Gabirela N.; Blackburn, Ninian J.; Vila, Alejandro J.; Murgida, Daniel H.

    2012-10-10

    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. In conclusion, 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.

  4. 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.

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

    NASA Astrophysics Data System (ADS)

    Cancès, Éric; Galicher, Hervé; Lewin, Mathieu

    2006-02-01

    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 latters. Numerical results for the special case of two-electron systems are provided: we compute the first singlet excited state potential energy surface of the H2 molecule.

  6. 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.

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

    PubMed Central

    Nair, Sunil; Stockert, O.; Witte, U.; Nicklas, M.; Schedler, R.; Kiefer, K.; Thompson, J. D.; Bianchi, A. D.; Fisk, Z.; Wirth, S.; Steglich, F.

    2010-01-01

    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. PMID:20457945

  8. Reconstruction of single-shell states for mid-heavy Sn isotopes

    NASA Astrophysics Data System (ADS)

    Dikmen, Erdal; Ozturk, Oguz

    2015-10-01

    A great exact truncation to construct single-shell states for the shell model description of mid-heavy Sn isotopes is offered in the framework of the Drexel University shell model approach. It is based on the occurrence of only one-column Young diagrams in building the multi-shell model states [1]. This truncation allows us to calculate the coefficient of fractional parentage (CFP) for the most stable Sn isotopes, e.g., 116 , 118 , 120Sn, by reducing the calculation requirements. An application to 116 , 118 , 120Sn isotopes in the sdgh-shell is presented. This work was supported by The Scientific and Technological Research Council of Turkey (TUBITAK) under Contract No. 114F333 and Suleyman Demirel University SDUBAP No. 4166-D2-14.

  9. 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.

  10. 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

  11. Charge transfer to ground-state ions produces free electrons

    NASA Astrophysics Data System (ADS)

    You, D.; Fukuzawa, H.; Sakakibara, Y.; Takanashi, T.; Ito, Y.; Maliyar, G. G.; Motomura, K.; Nagaya, K.; Nishiyama, T.; Asa, K.; Sato, Y.; Saito, N.; Oura, M.; Schöffler, M.; Kastirke, G.; Hergenhahn, U.; Stumpf, V.; Gokhberg, K.; Kuleff, A. I.; Cederbaum, L. S.; Ueda, K.

    2017-01-01

    Inner-shell ionization of an isolated atom typically leads to Auger decay. In an environment, for example, a liquid or a van der Waals bonded system, this process will be modified, and becomes part of a complex cascade of relaxation steps. Understanding these steps is important, as they determine the production of slow electrons and singly charged radicals, the most abundant products in radiation chemistry. In this communication, we present experimental evidence for a so-far unobserved, but potentially very important step in such relaxation cascades: Multiply charged ionic states after Auger decay may partially be neutralized by electron transfer, simultaneously evoking the creation of a low-energy free electron (electron transfer-mediated decay). This process is effective even after Auger decay into the dicationic ground state. In our experiment, we observe the decay of Ne2+ produced after Ne 1s photoionization in Ne-Kr mixed clusters.

  12. Charge transfer to ground-state ions produces free electrons

    PubMed Central

    You, D.; Fukuzawa, H.; Sakakibara, Y.; Takanashi, T.; Ito, Y.; Maliyar, G. G.; Motomura, K.; Nagaya, K.; Nishiyama, T.; Asa, K.; Sato, Y.; Saito, N.; Oura, M.; Schöffler, M.; Kastirke, G.; Hergenhahn, U.; Stumpf, V.; Gokhberg, K.; Kuleff, A. I.; Cederbaum, L. S.; Ueda, K

    2017-01-01

    Inner-shell ionization of an isolated atom typically leads to Auger decay. In an environment, for example, a liquid or a van der Waals bonded system, this process will be modified, and becomes part of a complex cascade of relaxation steps. Understanding these steps is important, as they determine the production of slow electrons and singly charged radicals, the most abundant products in radiation chemistry. In this communication, we present experimental evidence for a so-far unobserved, but potentially very important step in such relaxation cascades: Multiply charged ionic states after Auger decay may partially be neutralized by electron transfer, simultaneously evoking the creation of a low-energy free electron (electron transfer-mediated decay). This process is effective even after Auger decay into the dicationic ground state. In our experiment, we observe the decay of Ne2+ produced after Ne 1s photoionization in Ne–Kr mixed clusters. PMID:28134238

  13. 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.

  14. Microwave zero-resistance states in a bilayer electron system.

    PubMed

    Wiedmann, S; Gusev, G M; Raichev, O E; Bakarov, A K; Portal, J C

    2010-07-09

    Magnetotransport measurements on a high-mobility electron bilayer system formed in a wide GaAs quantum well reveal vanishing dissipative resistance under continuous microwave irradiation. Profound zero-resistance states (ZRS) appear even in the presence of additional intersubband scattering of electrons. We study the dependence of photoresistance on frequency, microwave power, and temperature. Experimental results are compared with a theory demonstrating that the conditions for absolute negative resistivity correlate with the appearance of ZRS.

  15. 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.

  16. 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.

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

    DOE PAGES

    Abriata, Luciano A.; Alvarez-Paggi, Damian; Ledesma, Gabirela N.; ...

    2012-10-10

    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 electronicmore » wave functions optimized for electron entry and exit, respectively, through two different and nearly perpendicular pathways. In conclusion, 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.« less

  18. 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.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Harris, J. W.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Heide, M.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Hess, B. A.; Hetland, K. F.; Hillemanns, H.; Hippolyte, B.; Hosokawa, R.; Hristov, P.; Huang, M.; Humanic, T. J.; Hussain, N.; Hussain, T.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Inaba, M.; Ippolitov, M.; Irfan, M.; Ivanov, M.; Ivanov, V.; Izucheev, V.; Jacobs, P. M.; Jadhav, M. B.; Jadlovska, S.; Jadlovsky, J.; Jahnke, C.; Jakubowska, M. J.; Jang, H. J.; Janik, M. A.; Jayarathna, P. H. S. Y.; Jena, C.; Jena, S.; Jimenez Bustamante, R. T.; Jones, P. G.; Jung, H.; Jusko, A.; Kalinak, P.; Kalweit, A.; Kamin, J.; Kang, J. H.; Kaplin, V.; Kar, S.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karayan, L.; Karpechev, E.; Kebschull, U.; Keidel, R.; Keijdener, D. L. D.; Keil, M.; Mohisin Khan, M.; Khan, P.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Kileng, B.; Kim, D. W.; Kim, D. J.; Kim, D.; Kim, H.; Kim, J. S.; Kim, M.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, C.; Klein, J.; Klein-Bösing, C.; Klewin, S.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobayashi, T.; Kobdaj, C.; Kofarago, M.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Kondratyuk, E.; Konevskikh, A.; Kopcik, M.; Kour, M.; Kouzinopoulos, C.; Kovalenko, O.; Kovalenko, V.; Kowalski, M.; Koyithatta Meethaleveedu, G.; Králik, I.; Kravčáková, A.; Kretz, M.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.; Kubera, A. M.; Kučera, V.; Kuhn, C.; Kuijer, P. G.; Kumar, A.; Kumar, J.; Kumar, L.; Kumar, S.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kweon, M. J.; Kwon, Y.; La Pointe, S. L.; La Rocca, P.; Ladron de Guevara, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; Lara, C.; Lardeux, A.; Lattuca, A.; Laudi, E.; Lea, R.; Leardini, L.; Lee, G. R.; Lee, S.; Lehas, F.; Lemmon, R. C.; Lenti, V.; Leogrande, E.; León Monzón, I.; León Vargas, H.; Leoncino, M.; Lévai, P.; Li, S.; Li, X.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Ljunggren, H. M.; Lodato, D. F.; Loenne, P. I.; Loginov, V.; Loizides, C.; Lopez, X.; López Torres, E.; Lowe, A.; Luettig, P.; Lunardon, M.; Luparello, G.; Maevskaya, A.; Mager, M.; Mahajan, S.; Mahmood, S. M.; Maire, A.; Majka, R. D.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manko, V.; Manso, F.; Manzari, V.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Margutti, J.; Marín, A.; Markert, C.; Marquard, M.; Martin, N. A.; Martin Blanco, J.; Martinengo, P.; Martínez, M. I.; Martínez García, G.; Martinez Pedreira, M.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Massacrier, L.; Mastroserio, A.; Matyja, A.; Mayer, C.; Mazer, J.; Mazzoni, M. A.; Mcdonald, D.; Meddi, F.; Melikyan, Y.; Menchaca-Rocha, A.; Meninno, E.; Mercado Pérez, J.; Meres, M.; Miake, Y.; Mieskolainen, M. M.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Minervini, L. M.; Mischke, A.; Mishra, A. N.; Miśkowiec, D.; Mitra, J.; Mitu, C. M.; Mohammadi, N.; Mohanty, B.; Molnar, L.; Montaño Zetina, L.; Montes, E.; Moreira De Godoy, D. A.; Moreno, L. A. P.; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Mühlheim, D.; Muhuri, S.; Mukherjee, M.; Mulligan, J. D.; Munhoz, M. G.; Munzer, R. H.; Murray, S.; Musa, L.; Musinsky, J.; Naik, B.; Nair, R.; Nandi, B. K.; Nania, R.; Nappi, E.; Naru, M. U.; Natal da Luz, H.; Nattrass, C.; Nayak, K.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Nellen, L.; Ng, F.; Nicassio, M.; Niculescu, M.; Niedziela, J.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Noferini, F.; Nomokonov, P.; Nooren, G.; Noris, J. C. C.; Norman, J.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Oh, S. K.; Ohlson, A.; Okatan, A.; Okubo, T.; Olah, L.; Oleniacz, J.; Oliveira Da Silva, A. C.; Oliver, M. H.; Onderwaater, J.; Oppedisano, C.; Orava, R.; Ortiz Velasquez, A.; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Ozdemir, M.; Pachmayer, Y.; Pagano, P.; Paić, G.; Pal, S. K.; Pan, J.; Pandey, A. K.; Papcun, P.; Papikyan, V.; Pappalardo, G. S.; Pareek, P.; Park, W. J.; Parmar, S.; Passfeld, A.; Paticchio, V.; Patra, R. N.; Paul, B.; Pei, H.; Peitzmann, T.; Pereira Da Costa, H.; Pereira De Oliveira Filho, E.; Peresunko, D.; Pérez Lara, C. E.; Perez Lezama, E.; Peskov, V.; Pestov, Y.; Petráček, V.; Petrov, V.; Petrovici, M.; Petta, C.; Piano, S.; Pikna, M.; Pillot, P.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; Płoskoń, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-Lerma, P. L. M.; Poghosyan, M. G.; Polichtchouk, B.; Poljak, N.; Poonsawat, W.; Pop, A.; Porteboeuf-Houssais, S.; Porter, J.; Pospisil, J.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puccio, M.; Puddu, G.; Pujahari, P.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rajput, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Rami, F.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Rascanu, B. T.; Rathee, D.; Read, K. F.; Redlich, K.; Reed, R. J.; Rehman, A.; Reichelt, P.; Reidt, F.; Ren, X.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Revol, J.-P.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Ristea, C.; Rocco, E.; Rodríguez Cahuantzi, M.; Rodriguez Manso, A.; Røed, K.; Rogochaya, E.; Rohr, D.; Röhrich, D.; Romita, R.; Ronchetti, F.; Ronflette, L.; Rosnet, P.; Rossi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Russo, R.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Sadovsky, S.; Šafařík, K.; Sahlmuller, B.; Sahoo, P.; Sahoo, R.; Sahoo, S.; Sahu, P. K.; Saini, J.; Sakai, S.; Saleh, M. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Šándor, L.; Sandoval, A.; Sano, M.; Sarkar, D.; Scapparone, E.; Scarlassara, F.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schuchmann, S.; Schukraft, J.; Schulc, M.; Schuster, T.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Šefčík, M.; Seger, J. E.; Sekiguchi, Y.; Sekihata, D.; Selyuzhenkov, I.; Senosi, K.; Senyukov, S.; Serradilla, E.; Sevcenco, A.; Shabanov, A.; Shabetai, A.; Shadura, O.; Shahoyan, R.; Shangaraev, A.; Sharma, A.; Sharma, M.; Sharma, M.; Sharma, N.; Shigaki, K.; Shtejer, K.; Sibiriak, Y.; Siddhanta, S.; Sielewicz, K. M.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Simonetti, G.; Singaraju, R.; Singh, R.; Singha, S.; Singhal, V.; Sinha, B. C.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Slupecki, M.; Smirnov, N.; Snellings, R. J. M.; Snellman, T. W.; Søgaard, C.; Song, J.; Song, M.; Song, Z.; Soramel, F.; Sorensen, S.; Sozzi, F.; Spacek, M.; Spiriti, E.; Sputowska, I.; Spyropoulou-Stassinaki, M.; Stachel, J.; Stan, I.; Stefanek, G.; Stenlund, E.; Steyn, G.; Stiller, J. H.; Stocco, D.; Strmen, P.; Suaide, A. A. P.; Sugitate, T.; Suire, C.; Suleymanov, M.; Suljic, M.; Sultanov, R.; Šumbera, M.; Szabo, A.; Szanto de Toledo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Tabassam, U.; Takahashi, J.; Tambave, G. J.; Tanaka, N.; Tangaro, M. A.; Tarhini, M.; Tariq, M.; Tarzila, M. G.; Tauro, A.; Tejeda Muñoz, G.; Telesca, A.; Terasaki, K.; Terrevoli, C.; Teyssier, B.; Thäder, J.; Thomas, D.; Tieulent, R.; Timmins, A. R.; Toia, A.; Trogolo, S.; Trombetta, G.; Trubnikov, V.; Trzaska, W. H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ullaland, K.; Uras, A.; Usai, G. L.; Utrobicic, A.; Vajzer, M.; Vala, M.; Valencia Palomo, L.; Vallero, S.; Van Der Maarel, J.; Van Hoorne, J. W.; van Leeuwen, M.; Vanat, T.; Vande Vyvre, P.; Varga, D.; Vargas, A.; Vargyas, M.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vauthier, A.; Vechernin, V.; Veen, A. M.; Veldhoen, M.; Velure, A.; Venaruzzo, M.; Vercellin, E.; Vergara Limón, S.; Vernet, R.; Verweij, M.; Vickovic, L.; Viesti, G.; Viinikainen, J.; Vilakazi, Z.; Villalobos Baillie, O.; Villatoro Tello, A.; Vinogradov, A.; Vinogradov, L.; Vinogradov, Y.; Virgili, T.; Vislavicius, V.; Viyogi, Y. P.; Vodopyanov, A.; Völkl, M. A.; Voloshin, K.; Voloshin, S. A.; Volpe, G.; von Haller, B.; Vorobyev, I.; Vranic, D.; Vrláková, J.; Vulpescu, B.; Vyushin, A.; Wagner, B.; Wagner, J.; Wang, H.; Wang, M.; Watanabe, D.; Watanabe, Y.; Weber, M.; Weber, S. G.; Weiser, D. F.; Wessels, J. P.; Westerhoff, U.; Whitehead, A. M.; Wiechula, J.; Wikne, J.; Wilde, M.; Wilk, G.; Wilkinson, J.; Williams, M. C. S.; Windelband, B.; Winn, M.; Yaldo, C. G.; Yang, H.; Yang, P.; Yano, S.; Yasar, C.; Yin, Z.; Yokoyama, H.; Yoo, I.-K.; Yoon, J. H.; Yurchenko, V.; Yushmanov, I.; Zaborowska, A.; Zaccolo, V.; Zaman, A.; Zampolli, C.; Zanoli, H. J. C.; Zaporozhets, S.; Zardoshti, N.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zgura, I. S.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhang, C.; Zhang, Z.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, Y.; Zhou, Z.; Zhu, H.; Zhu, J.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zinovjev, G.; Zyzak, M.

    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.

  19. 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......

  20. 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

  1. 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.

  2. 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.

  3. Electron correlations in the L-shell photoionization of heavy elements

    NASA Astrophysics Data System (ADS)

    Jitschin, W.; Werner, U.; Materlik, G.; Doolen, G. D.

    1987-06-01

    The photoionization of the individual L subshells of 72Hf, 74W, 78Pt, 79Au, and 82Pb in the energy regime of the L edges has been studied in detail. Experimentally, the x-ray absorption spectra of thin sample foils were recorded using monochromatized synchrotron radiation. The energy dependence of the absorption is governed in its gross structure by the atomic photoionization with some superimposed oscillatory structure due to solid-state effects. The experimental data are compared to various theoretical predictions for atomic photoionization. Calculations in the framework of an independent-electron approach predict a smooth, power-law-like energy dependence. In contrast, the experimental data show small but significant deviations from such a behavior. The dispersionlike deviations are attributed to electron-correlation effects, as is confirmed by comparative calculations of photoionization with inclusion or omission of the correlations using the computer code of Liberman and Zangwill [Comput. Phys. Commun. 32, 75 (1984)]. The main influence of the correlation effects on the subshell ionization cross sections originates from the dielectric (anti-) screening of the external radiation field. Calculations in the local-density approximation for the response of the atom to the radiation field yield an even quantitative description of the experimental data in a large fraction of the investigated energy range.

  4. 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.

  5. 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.

  6. 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.

  7. Influence of the metabolic state on the tolerance of Pichia kudriavzevii to heavy metals.

    PubMed

    Mesquita, Vanessa A; Machado, Manuela D; Silva, Cristina F; Soares, Eduardo V

    2016-11-01

    This work aims to examine the influence of the metabolic state of the yeast Pichia kudriavzevii on the susceptibility to a metals mixture (5 mg L(-1) Cd, 10 mg L(-1) Pb, and 5 mg L(-1) Zn). Cells exposed to the metals mixture in the presence of 25 mmol L(-1) glucose displayed a higher loss of membrane integrity and proliferation capacity, compared to cells incubated in the absence of glucose. The analysis of the effect of individual metals revealed that glucose increased the toxic effect of Cd marginally, and of Pb significantly. The increased susceptibility to heavy metals due to glucose was attenuated in the simultaneous presence of a mitochondrial respiration inhibitor such as sodium azide (NaN3 ). ATP-depleted yeast cells, resulting from treatment with the non-metabolizable glucose analogue 2-deoxy-d-glucose, showed an increased susceptibility to heavy metals mixture. Pre-incubation of yeast cells with 1 or 1.5 mmol L(-1) Ca(2+) reduced significantly (P < 0.05) the loss of membrane integrity induced by the metals mixture. These findings contribute to the understanding of metals mechanisms of toxicity in the non-conventional yeast P. kudriavzevii.

  8. Electronic State Decomposition of Energetic Materials and Model Systems

    DTIC Science & Technology

    2010-11-17

    tetrazine1,4-dioxde ( DATO ), is investigated. Although these molecules are based on N -oxides of a tetrazine aromatic heterocyclic ring, their...nitramines, furazan, tetrazines, tetrazine-N oxides, terazoles, PETN, RDX,HMX,CL-20,DAATO,ACTO, DATO ,conical intersections Elliot R Bernstein Colorado State...Tetrazine-N-Oxide Based High Nitrogen Content Energetic Materials from Excited Electronic States," J. Chem. Phys. 131, 194304 (2009). A

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

    PubMed Central

    Yang, Yang; Yang, Weitao

    2016-01-01

    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 1Ag 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 3B2u 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 1B2u is a zwitterionic state to the short axis. The excited 1Ag 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 1B2u and excited 1Ag 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. 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

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

    PubMed

    Dou, Wenjie; Subotnik, Joseph E

    2016-08-07

    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.

  12. 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.

  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 PAGES

    Willers, Thomas; Strigari, Fabio; Hu, Zhiwei; ...

    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

    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

    2015-02-24

    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.

  16. Ultrafast Spectroscopy of Delocalized Excited States of the Hydrated Electron

    SciTech Connect

    Paul F. Barbara

    2005-09-28

    Research under support of this grant has been focused on the understanding of highly delocalized ''conduction-band-like'' excited states of solvated electrons in bulk water, in water trapped in the core of reverse micelles, and in alkane solvents. We have strived in this work to probe conduction-band-like states by a variety of ultrafast spectroscopy techniques. (Most of which were developed under DOE support in a previous funding cycle.) We have recorded the optical spectrum of the hydrated electron for the first time. This was accomplished by applying a photo-detrapping technique that we had developed in a previous funding cycle, but had not yet been applied to characterize the actual spectrum. In the cases of reverse micelles, we have been investigating the potential role of conduction bands in the electron attachment process and the photoinduced detrapping, and have published two papers on this topic. Finally, we have been exploring solvated electrons in isooctane from various perspectives. All of these results strongly support the conclusion that optically accessible, highly delocalized electronic states exist in these various media.

  17. 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

  18. Status of state electronic disease surveillance systems--United States, 2007.

    PubMed

    2009-07-31

    The National Electronic Disease Surveillance System (NEDSS) is a web-based system that uses standard health information technology (IT) codes to integrate disease surveillance systems, enabling them to transfer public health, laboratory, and clinical data securely from health-care providers to public health departments. Each jurisdictions' system consists of a base system and modules that can be used for specific surveillance purposes. States also use NEDSS-like or other electronic systems to conduct surveillance on specific diseases or conditions. Until recently, no assessment had been done to describe the status and characteristics of state electronic disease surveillance systems. The Council of State and Territorial Epidemiologists (CSTE) conducted such an assessment in August 2007 in all 50 states. This report presents the results of that assessment, which indicated that, in 2007, state electronic disease surveillance systems varied widely and were in various stages of implementation. Each state had either custom-built systems or purchased systems that were customizable, with associated disease modules to meet its own surveillance needs. As interoperability becomes the standard for electronic data sharing, more states will face customization costs and the need to hire more technical specialists who can manage health information and exchange. Further collaboration and support from surveillance and health-care IT stakeholders with public health will be needed to improve the efficacy and quality of electronic disease surveillance systems.

  19. 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.

  20. 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.

  1. 45 CFR 265.6 - Must States file reports electronically?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 2 2010-10-01 2010-10-01 false Must States file reports electronically? 265.6 Section 265.6 Public Welfare Regulations Relating to Public Welfare OFFICE OF FAMILY ASSISTANCE (ASSISTANCE PROGRAMS), ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES...

  2. Determining the Origins of Electronic States in Semiconductor Nanostructures

    SciTech Connect

    Goldman, Rachel S.; Johnson, H. T.

    2014-12-15

    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. Spilling of electronic states in Pb quantum wells

    NASA Astrophysics Data System (ADS)

    Jałochowski, M.; Palotás, K.; Krawiec, M.

    2016-01-01

    Energy-dependent apparent step heights of two-dimensional ultrathin Pb islands grown on the Si(111)6 ×6 -Au surface have been investigated by a combination of scanning tunneling microscopy, first-principles density-functional theory, and the particle-in-a-box model calculations. The apparent step height shows the thickness- and energy-dependent oscillatory behaviors, which are directly related to the spilling of electron states into the vacuum exhibiting a quantum size effect. This has been unambiguously proven by extensive first-principles scanning tunneling microscopy and spectroscopy simulations. An electronic contribution to the apparent step height is directly determined. At certain energies it reaches values as high as a half of the atomic contribution. The applicability of the particle-in-a-box model to the spilling of electron states is also discussed.

  4. Internal conversion from excited electronic states of 229Th ions

    NASA Astrophysics Data System (ADS)

    Bilous, Pavlo V.; Kazakov, Georgy A.; Moore, Iain D.; Schumm, Thorsten; Pálffy, Adriana

    2017-03-01

    The process of internal conversion from excited electronic states is investigated theoretically for the case of the vacuum-ultraviolet nuclear transition of 229Th. Due to the very low transition energy, the 229Th nucleus offers the unique possibility to open the otherwise forbidden internal conversion nuclear decay channel for thorium ions via optical laser excitation of the electronic shell. We show that this feature can be exploited to investigate the isomeric state properties via observation of internal conversion from excited electronic configurations of +Th and Th+2 ions. A possible experimental realization of the proposed scenario at the nuclear laser spectroscopy facility IGISOL in Jyväskylä, Finland, is discussed.

  5. Electronic density of states in sequence dependent DNA molecules

    NASA Astrophysics Data System (ADS)

    de Oliveira, B. P. W.; Albuquerque, E. L.; Vasconcelos, M. S.

    2006-09-01

    We report in this work a numerical study of the electronic density of states (DOS) in π-stacked arrays of DNA single-strand segments made up from the nucleotides guanine G, adenine A, cytosine C and thymine T, forming a Rudin-Shapiro (RS) as well as a Fibonacci (FB) polyGC quasiperiodic sequences. Both structures are constructed starting from a G nucleotide as seed and following their respective inflation rules. Our theoretical method uses Dyson's equation together with a transfer-matrix treatment, within an electronic tight-binding Hamiltonian model, suitable to describe the DNA segments modelled by the quasiperiodic chains. We compared the DOS spectra found for the quasiperiodic structure to those using a sequence of natural DNA, as part of the human chromosome Ch22, with a remarkable concordance, as far as the RS structure is concerned. The electronic spectrum shows several peaks, corresponding to localized states, as well as a striking self-similar aspect.

  6. 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.

  7. The low-lying electronic states of ReB.

    PubMed

    Borin, Antonio Carlos; Gobbo, João Paulo; Castro, César Augusto Milani

    2014-07-01

    The ground and low-lying electronic states of ReB were studied at the CASPT2//CASSCF level (multiconfigurational second-order perturbation theory) and quadruple-ζ ANO-RCC basis sets. Spectroscopic constants, potential energy curves, wavefunctions, and Mulliken population analysis are given. The ground state of ReB is of X(5)Σ(+) symmetry (R e  = 1.817 Å, ω e  = .909 cm(-1), and μ = 2.87 D), giving rise to a Ω = 0(+) ground state after including spin-orbit coupling.

  8. The electronic properties of superatom states of hollow molecules.

    PubMed

    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 sp(2) 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 C(60) 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

  9. 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.

  10. 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.

  11. Electronic states of PF 2 and PF +2

    NASA Astrophysics Data System (ADS)

    Latifzadeh, Lida; Balasubramanian, K.

    1994-10-01

    The ground and excited electronic states of PF 2 and PF +2 have been investigated using the complete active space self-consistent field (CASSCF) followed by multi-reference singles and doubles configuration interaction (MRSDCI) methods that include up to 1.2 million configurations. These states include X 2B 1, 4A 2, 2A 1(I), 2A 1(II), 2A 2, 2B 2(I), 2B 2(II), 4B 1, 2B 1(II) for PF 2 and 1A 1, 3B 1, 1B 1 for PF +2. Both all-electron computations employing large basis sets and relativistic effective core potentials using valence basis sets were carried out. The spectroscopic properties were determined for the bound states. The dissociation energy of PFF is obtained using the full second-order configuration interaction (SOCI) and CASSCF/MRSDCI methods.

  12. 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.

  13. Optical limiting and picosecond relaxation of carbocyanines upper electronic states

    NASA Astrophysics Data System (ADS)

    Oulianov, D. A.; Dvornikov, A. S.; Rentzepis, P. M.

    2002-05-01

    Nonlinear absorption, anomalous fluorescence and relaxation of high-lying electronic states in six carbocyanine dyes, including cryptocyanine (DCI), DDI, DTDCI, DTTCI, DOTCI and HDIDCI, in solution and in polymer, were studied by means of picosecond transient absorption spectroscopy and nonlinear transmission experiments. Absorption cross-sections of the S 1→S n transition, and decay rates of the second singlet excited state, S 2, were measured. All dyes showed strong reverse saturable absorption in the 450-600 nm region with large excited to ground state absorption cross-section ratios. For DTDCI this ratio, at 470 nm, was measured to be 350, which is the largest ever reported. All molecules have shown strong optical limiting effect. However, in all molecules except DCI a saturation of the optical limiting process was observed as expected, owing to relatively long, up to 17.5 ps, lifetime of the S 2 state. The S 2 state fluorescence quantum yields were also measured.

  14. 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.

  15. 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.

  16. Simulation study of radial dose due to the irradiation of a swift heavy ion aiming to advance the treatment planning system for heavy particle cancer therapy: The effect of emission angles of secondary electrons

    NASA Astrophysics Data System (ADS)

    Moribayashi, Kengo

    2015-12-01

    A radial dose simulation model has been proposed in order to advance the treatment planning system for heavy particle cancer therapy. Here, the radial dose is the dose due to the irradiation of a heavy ion as a function of distances from this ion path. The model proposed here may overcome weak points of paradigms that are employed to produce the conventional radial dose distributions. To provide the radial dose with higher accuracy, this paper has discussed the relationship between the emission angles of secondary electrons and the radial dose. It is found that the effect of emission angles becomes stronger on the radial dose with increasing energies of the secondary electrons.

  17. 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

  18. 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.

  19. 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

  20. 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.

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

    PubMed

    Fu, Liang

    2010-02-05

    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.

  2. 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.

  3. Controlled interaction of surface quantum-well electronic states.

    PubMed

    Seufert, Knud; Auwärter, Willi; García de Abajo, F J; Ecija, David; Vijayaraghavan, Saranyan; Joshi, Sushobhan; Barth, Johannes V

    2013-01-01

    We report on the construction of well-defined surface quantum well arrangements by combining self-assembly protocols and molecular manipulation procedures. After the controlled removal of individual porphyrin molecules from dense-packed arrays on Ag(111), the surface state electrons are confined at the bare silver patches. These act as quantum wells that show well-defined unoccupied bound surface states. Scanning tunneling spectroscopy and complementary boundary element method calculations are performed to characterize the interaction between the bound states of adjacent quantum wells and reveal a hybridization of wave functions resulting in bonding and antibonding states. The interwell coupling can be tuned by the deliberate choice of the molecules acting as potential barriers. The fabrication method is shown to be ideally suited to engineer specific configurations as one-dimensional chains or two-dimensional artificial molecules.

  4. 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.

  5. Evolution of electronic states in fullerenes with size

    NASA Astrophysics Data System (ADS)

    Dong, Jianjun; Drabold, David A.

    1996-04-01

    The electronic density of states (DOS) of fullerenes is studied in this paper. The DOS of small fullerences (C_60 and C_240) is computed with exact diagonalization, while the DOS of large fullerences (C_540, C_960, C_2169 and C_3840) is computed with a newly developed ``Order N" electronic structure method: the maximum entropy method (Maxent) footnote D.A. Drabold, O.F. Sankey, Phys. Rev. Lett. 70 3631,(1995). The projected DOS at different types of sites (pentagon site and facet center hexagon site) is also computed with Maxent. We illustrate the size dependence and the cluster to crystal evolution. footnote D.A. Drabold, P.Ordejón, J. Dong and R.M. Martin, Solid State Commun.,96 833, (1995). We observe that the DOS closely approximates graphite for relaxed C_2160 and C_3840.

  6. 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.

  7. 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.

  8. Electronic spectrum and localization of electronic states in aperiodic quantum dot chains

    NASA Astrophysics Data System (ADS)

    Korotaev, P. Yu.; Vekilov, Yu. Kh.; Kaputkina, N. E.

    2014-02-01

    The electronic energy spectra of aperiodic Thue-Morse, Rudin-Shapiro, and double-periodic quantum dot chains are investigated in the tight-binding approximation. The dependence of the spectrum on all parameters of a "mixed" aperiodic chain model is studied: the electronic energy at quantum dots and the hopping integrals. The electronic degree of localization in the chains under consideration is determined by analyzing the inverse participation ratio. Its spectral distribution and the dependence of the band-averaged degree of localization on these model parameters have been calculated. It is shown that a transition of the system's sites to a resonant state in which the degree of electron localization decreases, while an overlap between the subbands occurs in the spectrum is possible when the parameters are varied.

  9. 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.

  10. Electronic thermal conductivity in a superconducting vortex state

    NASA Astrophysics Data System (ADS)

    Adachi, H.; Miranovic, P.; Ichioka, M.; Machida, K.

    2007-10-01

    The longitudinal component of the electronic thermal conductivity κxx in a superconducting vortex state is calculated as a function of magnetic field B. Calculations are performed by taking account of the spatial dependence of normal Green's function g, which was neglected in the previous studies using the Brandt-Pesch-Tewordt method. We discuss the possibility of using κxx(B) as a probe of the pair potential symmetry.

  11. 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.

  12. 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.

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

    DOE PAGES

    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.

  14. Glycine in an electronically excited state: ab initio electronic structure and dynamical calculations.

    PubMed

    Muchová, Eva; Slavícek, Petr; Sobolewski, Andrzej L; Hobza, Pavel

    2007-06-21

    The goal of this study is to explore the photochemical processes following optical excitation of the glycine molecule into its two low-lying excited states. We employed electronic structure methods at various levels to map the PES of the ground state and the two low-lying excited states of glycine. It follows from our calculations that the photochemistry of glycine can be regarded as a combination of photochemical behavior of amines and carboxylic acid. The first channel (connected to the presence of amino group) results in ultrafast decay, while the channels characteristic for the carboxylic group occur on a longer time scale. Dynamical calculations provided the branching ratio for these channels. We also addressed the question whether conformationally dependent photochemistry can be observed for glycine. While electronic structure calculations favor this possibility, the ab initio multiple spawning (AIMS) calculations showed only minor relevance of the reaction path resulting in conformationally dependent dynamics.

  15. 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.

  16. 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.

  17. 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.

  18. Model for primary electron transfer and coupling of electronic states at reaction centers of purple bacteria

    NASA Astrophysics Data System (ADS)

    Pavlovich, V. S.

    2006-05-01

    A detailed derivation is presented for relations making it possible to describe the effect of temperature on the halfwidth of the P960 and P870 absorption bands and also on the electron transfer (ET) rate at reaction centers (RCs) of the purple bacteria Rps. viridis and Rb. sphaeroides. Primary electron transfer is considered as a resonant nonradiative transition between P* and P+B L - states (where P is a special pair, BL is an additional bacteriochlorophyll in the L branch of the reaction center). It has been shown that the vibrational hα mode with frequency 130 150 cm-1 controls primary electron transfer. It has been found that the matrix element of the electronic transition between the states P* and P+B L - is equal to 12.7 ± 0.9 and 12.0 ± 1.2 cm-1 for Rps. viridis and Rb. sphaeroides respectively. The mechanism is discussed for electron transport from P* and BL and then to bacteriopheophytin HL.

  19. 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.

  20. Theory of electron transfer and molecular state in DNA

    NASA Astrophysics Data System (ADS)

    Endres, Robert Gunter

    2002-09-01

    In this thesis, a mechanism for long-range electron transfer in DNA and a systematic search for high conductance DNA are developed. DNA is well known for containing the genetic code of all living species. On the other hand, there are some experimental indications that DNA can mediate effectively long-range electron transfer leading to the concept of chemistry at a distance. This can be important for DNA damage and healing. In the first part of the thesis, a possible mechanism for long-range electron transfer is introduced. The weak distance dependent electron transfer was experimentally observed using transition metal intercalators for donor and acceptor. In our model calculations, the transfer is mediated by the molecular analogue of a Kondo bound state well known from solid state physics of mixed-valence rare-earth compounds. We believe this is quite realistic, since localized d orbitals of the transition metal ions could function as an Anderson impurity embedded in a reservoir of rather delocalized molecular orbitals of the intercalator ligands and DNA pi orbitals. The effective Anderson model is solved with a physically intuitive variational ansatz as well as with the essentially exact DMRG method. The electronic transition matrix element, which is important because it contains the donor-acceptor distance dependence, is obtained with the Mulliken-Hush algorithm as well as from Born-Oppenheimer potential energy surfaces. Our possible explanation of long-range electron transfer is put in context to other more conventional mechanisms which also could lead to similar behavior. Another important issue of DNA is its possible use for nano-technology. Although DNA's mechanical properties are excellent, the question whether it can be conducting and be used for nano-wires is highly controversial. Experimentally, DNA shows conducting, semi-conducting and insulating properties. Motivated by these wide ranging experimental results on the conductivity of DNA, we have

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  3. Exploring the electronic states of iodocarbyne: a theoretical contribution.

    PubMed

    Alves, Tiago Vinicius; Ornellas, Fernando R

    2014-05-28

    A manifold of electronic states correlating with the two lowest-lying dissociation channels of the iodocarbyne (CI) species is theoretically characterized for the first time in the literature. A contrast between the Λ + S and the relativistic (Ω) descriptions clearly shows the effect of perturbations on electronic states above 20 000 cm(-1) and the potential difficulties to detect them experimentally. For the bound states, spectroscopic parameters were evaluated, as well as the dipole moment functions. Similarly to CO, the polarity predicted for this iodocarbyne is C(δ-)I(δ+); as illustrated in the text, this is also the case for the other halocarbynes. As a potential mechanism for the experimental spectroscopic characterization of CI, we suggest the radiative association between C and I atoms, with light emitted in the red region of the visible spectra. Transition probabilities were also evaluated predicting very weak intensities. For the states 1/2(II) and 3/2(II), we have estimated radiative lifetimes of 7.1 and 714 ms, respectively.

  4. Single electron probes of fractional quantum hall states

    NASA Astrophysics Data System (ADS)

    Venkatachalam, Vivek

    When electrons are confined to a two dimensional layer with a perpendicular applied magnetic field, such that the ratio of electrons to flux quanta (nu) is a small integer or simple rational value, these electrons condense into remarkable new phases of matter that are strikingly different from the metallic electron gas that exists in the absence of a magnetic field. These phases, called integer or fractional quantum Hall (IQH or FQH) states, appear to be conventional insulators in their bulk, but behave as a dissipationless metal along their edge. Furthermore, electrical measurements of such a system are largely insensitive to the detailed geometry of how the system is contacted or even how large the system is... only the order in which contacts are made appears to matter. This insensitivity to local geometry has since appeared in a number of other two and three dimensional systems, earning them the classification of "topological insulators" and prompting an enormous experimental and theoretical effort to understand their properties and perhaps manipulate these properties to create robust quantum information processors. The focus of this thesis will be two experiments designed to elucidate remarkable properties of the metallic edge and insulating bulk of certain FQH systems. To study such systems, we can use mesoscopic devices known as single electron transistors (SETs). These devices operate by watching single electrons hop into and out of a confining box and into a nearby wire (for measurement). If it is initially unfavorable for an electron to leave the box, it can be made favorable by bringing another charge nearby, modifying the energy of the confined electron and pushing it out of the box and into the nearby wire. In this way, the SET can measure nearby charges. Alternatively, we can heat up the nearby wire to make it easier for electrons to enter and leave the box. In this way, the SET is a sensitive thermometer. First, by operating the SET as an

  5. 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.

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

    NASA Astrophysics Data System (ADS)

    Robledo, L. M.

    2015-10-01

    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 254No. These are two and four-quasiparticle excitations that are treated in the same self-consistent HFB plus blocking framework as the odd mass states.

  7. 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.

  8. 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.

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

    PubMed

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    2016-01-01

    A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons ([Formula: see text]) in proton-proton collisions collected by the CMS experiment at the LHC at [Formula: see text]. The data correspond to an integrated luminosity of 19.7[Formula: see text]. The search considers [Formula: see text] resonances with masses between 1 and 3[Formula: see text], 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 [Formula: see text] 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 [Formula: see text] range from 10 to 1.5[Formula: see text] for the mass of X from 1.15 to 2.0[Formula: see text], significantly extending previous searches. For a warped extra dimension theory with a mass scale [Formula: see text] [Formula: see text], the data exclude radion scalar masses between 1.15 and 1.55[Formula: see text].

  10. 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.

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

    SciTech Connect

    Khachatryan, Vardan

    2016-07-04

    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 $\\sqrt{s}$ = 8 TeV. The data correspond to an integrated luminosity of 19.7 fb-1. The search considers HH 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-tbar 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 $\\sigma$(gg → X) B(X → HH → $b\\bar{b}b\\bar{b}$) 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 $\\Lambda_R$ = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV.

  12. 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}.

  13. 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.

  14. On the Electron Gas Heat Capacity in Undergraduate Solid State

    NASA Astrophysics Data System (ADS)

    Hasbun, Javier

    2013-03-01

    In undergraduate solid state physics the electronic energy, Uel, is calculated through the Fermi distribution function while the energy is weighted with the density of states. The electronic heat capacity is the derivative of the electronic energy with respect to temperature. Through this process, it is possible to obtain a low temperature approximation for the heat capacity, Cel that's proportional to the temperature. It is of interest to do a numerical calculation of Uel from which the numerical Cel is extracted. However, the result obtained, while agreeing with the low temperature approximation, has a slope that's substantially different. The disagreement appears large as the temperature is increased from zero K. Here we show that the reason has to do with the constancy of the Fermi level. By including the self consistent behavior of the chemical potential, the deviation from zero Kelvin is much improved and the result seems to make better sense. The lesson learned is significant enough to be of great pedagogical importance as regards the heat capacity calculation and the behavior of the chemical potential with temperature.

  15. 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.

  16. 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.

  17. Efficient numerical simulation of electron states in quantum wires

    NASA Technical Reports Server (NTRS)

    Kerkhoven, Thomas; Galick, Albert T.; Ravaioli, Umberto; Arends, John H.; Saad, Youcef

    1990-01-01

    A new algorithm is presented for the numerical simulation of electrons in a quantum wire as described by a two-dimensional eigenvalue problem for Schroedinger's equation coupled with Poisson's equation. Initially, the algorithm employs an underrelaxed fixed point iteration to generate an approximation which is reasonably close to the solution. Subsequently, this approximate solution is employed as an initial guess for a Jacobian-free implementation of an approximate Newton method. In this manner the nonlinearity in the model is dealt with effectively. The effectiveness of this approach is demonstrated in a set of numerical experiments which study the electron states on the cross section of a quantum wire structure based on III-V semiconductors at 4.2 and 77 K.

  18. Electronic structure and magnetic state of transuranium metals under pressure.

    PubMed

    Lukoyanov, A V; Shorikov, A O; Bystrushkin, V B; Dyachenko, A A; Kabirova, L R; Tsiovkin, Yu Yu; Povzner, A A; Dremov, V V; Korotin, M A; Anisimov, V I

    2010-12-15

    The electronic structures of bcc Np, fcc Pu, Am, and Cm pure metals under pressure have been investigated employing the LDA + U method with spin-orbit coupling (LDA + U + SO). The magnetic state of the actinide ions was analyzed in both LS and jj coupling schemes to reveal the applicability of corresponding coupling bases. It was demonstrated that whereas Pu and Am are well described within the jj coupling scheme, Np and Cm can be described appropriately neither in a {mσ}, nor in a {jmj} basis, due to intermediate coupling scheme realization in these metals that requires some finer treatment. The LDA + U + SO results for the considered transuranium metals reveal band broadening and gradual 5f electron delocalization under pressure.

  19. Role of ionization-excitation processes in the cross section for direct ionization of heavy atomic ions by electron impact

    NASA Astrophysics Data System (ADS)

    Zeng, J. L.; Liu, L. P.; Liu, P. F.; Yuan, J. M.

    2014-10-01

    The contribution to the ionization cross section of ionization-excitation processes by electron impact is usually negligibly small for low- and medium-Z elements. We demonstrate here, however, that for heavy atomic ions with the outermost shell being n d (n =4 ,5 ) the ionization-excitation processes play an evident role in the ionization cross section. For the 4 s24 p64 d10 ground level of Gd18 +, the ionization-excitation cross section due to the excitation of levels in the 4 s24 p64 d84 f configuration is comparable to the direct 4 p and 4 s ionization cross sections of (4s24 p54 d10) 1 /2 and (4s 4 p64 d10) 1 /2. The total ionization cross section will be underestimated by 15% without including the contribution from ionization-excitation processes. This is a general conclusion for heavy atomic ions, which is verified by taking Pd-like ions of Sn4 +,Ba10 +,Nd14 +,Tb19 +,Yb24 +, and W28 + as examples. The role of ionization-excitation processes can be understood from the overlapping of the wave functions between the 4 d and 4 f orbitals.

  20. 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.

  1. Use of scalp hair as indicator of human exposure to heavy metals in an electronic waste recycling area.

    PubMed

    Wang, Thanh; Fu, Jianjie; Wang, Yawei; Liao, Chunyang; Tao, Yongqing; Jiang, Guibin

    2009-01-01

    Scalp hair samples were collected at an electronic waste (e-waste) recycling area and analyzed for trace elements and heavy metals. Elevated levels were found for Cu and Pb with geometric means (GMs) at 39.8 and 49.5 microg/g, and the levels of all elements were found in the rank order Pb > Cu > Mn > Ba > Cr > Ni > Cd > As > V. Besides Cu and Pb, Cd (GM: 0.518 microg/g) was also found to be significantly higher compared to that in hair samples from control areas. Differences with age, gender, residence status and villages could be distinguished for most of the elements. The high levels of Cd, Cu and Pb were likely found to be originated from e-waste related activities, and specific sources were discussed. This study shows that human scalp hair could be a useful biomarker to assess the extent of heavy metal exposure to workers and residents in areas with intensive e-waste recycling activities.

  2. 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.

  3. Dimers of heavy p-elements of groups IV-VI: Electronic, vibrational, and magnetic properties

    NASA Astrophysics Data System (ADS)

    Borisova, S. D.; Rusina, G. G.; Eremeev, S. V.; Chulkov, E. V.

    2016-04-01

    Equilibrium lengths and binding energies, vibrational frequencies, width of the HOMO-LUMO gap, and the magnetic anisotropy energies for one- and two-component dimers of heavy p elements of Groups IV (Sn, Pb), V (Sb, Bi), and VI (Se, Te) with a pronounced relativistic effect have been calculated with the use of the formalism of the density functional theory. It has been shown that it is necessary to take into account the spin-orbit coupling, which significantly affects the energy parameters of clusters. The analysis of the data obtained has revealed that the Pb-Te, Pb-Se, Sn-Te, and Sn-Se dimers have the widest gap at the Fermi level and the lowest reactivity. The magnetic anisotropy energy has been calculated for all single- and doublecomponent dimers and the direction of the easy magnetization axis has been determined.

  4. Decay of the Iπ=8- isomeric state in 134Nd and 184Pt studied by electron and γ spectroscopy

    NASA Astrophysics Data System (ADS)

    Perkowski, J.; Andrzejewski, J.; Droste, Ch.; Janiak, Ł.; Grodner, E.; Rohoziński, S. G.; Próchniak, L.; Srebrny, J.; Samorajczyk-Pyśk, J.; Abraham, T.; Hadyńska-KlÈ©k, K.; Kisieliński, M.; Komorowska, M.; Kowalczyk, M.; Kownacki, J.; Marchlewski, T.; Mierzejewski, J.; Napiorkowski, P.; Stolarz, A.; Korman, A.; Zielińska, M.

    2017-01-01

    The properties of the K -isomer decays in the 134Nd and 184Pt nuclei have been investigated. Measurements were carried out in e -γ and γ -γ coincidence modes using electron spectrometers coupled to the central European Array for Gamma Levels Evaluations at the Heavy Ion Laboratory of the University of Warsaw. Internal conversion coefficients were obtained for transitions relevant to the decay of the isomeric states, allowing the determination of multipolarities and mixing ratios as well as hindrance factors. Two possible causes of the weakening of the K forbiddenness, namely rotational K mixing (Coriolis interaction) and triaxiality, are briefly discussed using schematic theoretical models.

  5. The electronic states of 2-furanmethanol (furfuryl alcohol) studied by photon absorption and electron impact spectroscopies

    NASA Astrophysics Data System (ADS)

    Giuliani, A.; Walker, I. C.; Delwiche, J.; Hoffmann, S. V.; Limão-Vieira, P.; Mason, N. J.; Heyne, B.; Hoebeke, M.; Hubin-Franskin, M.-J.

    2003-10-01

    The photoelectron spectrum of 2-furanmethanol (furfuryl alcohol) has been measured for ionization energies between 8 and 11.2 eV and the first three ionization bands assigned to π3, π2, and no ionizations in order of increasing binding energy. The photoabsorption spectrum has been recorded in the gas phase using both a synchrotron radiation source (5-9.91 eV, 248-125 nm) and electron energy-loss spectroscopy under electric-dipole conditions (5-10.9 eV, 248-90 nm). The (UV) absorption spectrum has also been recorded in solution (4.2-6.36 eV, 292-195 nm). The electronic excitation spectrum appears to be dominated by transitions between π and π* orbitals in the aromatic ring, leading to the conclusion that the frontier molecular orbitals of furan are affected only slightly on replacement of a H atom by the -CH2OH group. Additional experiments investigating electron impact at near-threshold energies have revealed two low-lying triplet states and at least one electron/molecule shape resonance. Dissociative electron attachment also shows to be widespread in furfuryl alcohol.

  6. Direct Imaging of Electron States in Open Quantum Dots

    NASA Astrophysics Data System (ADS)

    Aoki, N.; Brunner, R.; Burke, A. M.; Akis, R.; Meisels, R.; Ferry, D. K.; Ochiai, Y.

    2012-03-01

    We use scanning gate microscopy to probe the ballistic motion of electrons within an open GaAs/AlGaAs quantum dot. Conductance maps are recorded by scanning a biased tip over the open quantum dot while a magnetic field is applied. We show that, for specific magnetic fields, the measured conductance images resemble the classical transmitted and backscattered trajectories and their quantum mechanical analogue. In addition, we prove experimentally, with this direct measurement technique, the existence of pointer states. The demonstrated direct imaging technique is essential for the fundamental understanding of wave function scarring and quantum decoherence theory.

  7. 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.

  8. 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

    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.

  9. Single- and multiple-electron loss cross-sections for fast heavy ions colliding with neutrals: Semi-classical calculations

    NASA Astrophysics Data System (ADS)

    Song, M.-Y.; Litsarev, M. S.; Shevelko, V. P.; Tawara, H.; Yoon, J.-S.

    2009-07-01

    Extensive calculations of single, multiple and total electron-loss cross-sections of fast heavy ions in collisions with neutral atoms are performed in the semi-classical approximation using the DEPOSIT code based on the energy deposition model and statistical distributions for ionization probabilities. The results are presented for Ar 1+, Ar 2+, Kr 7+, Xe 3+, Xe 18+, Pb 25+ and U q+ ( q = 10, 28, 39, 62) ions colliding with H, N, Ne, Ar, Kr, Xe and U atoms at energies E > 1 MeV/u and compared with available experimental data and the n-particle classical-trajectory Monte Carlo ( nCTMC) calculations. The results show that the present semi-classical model can be applied for estimation of multiple and total electron-loss cross-sections within accuracies of a factor of 2. From calculated data for the total electron-loss cross-sections σ tot, their dependencies on relative velocity v, the first ionization potential I1 of the projectile and the target atomic number Z A are found and a semi-empirical formula for σ tot is suggested. The velocity range, where the semi-classical approximation can be used, is discussed.

  10. Simultaneous atomic-resolution electron ptychography and Z-contrast imaging of light and heavy elements in complex nanostructures

    NASA Astrophysics Data System (ADS)

    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.

    2016-08-01

    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.

  11. 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

  12. 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.

  13. 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.

  14. Electronic states of InSe/GaSe superlattice

    NASA Astrophysics Data System (ADS)

    Erkoç, Ş.; Allahverdi, K.; Ibrahim, Z.

    1994-06-01

    Analysis of recent publications revealed an increasing interest in epitaxial growth of InSe/GaSe superlattice. Within the effective mass theory we carried out self-consistent calculations of the confined and itinerant electronic states, potential profile and charge density distribution of InSe/GaSe superlattice, where the InSe layers are the well and the GaSe layers the barrier. Calculations were performed for three types of doping: uniform, modulated in the well, and modulated in the barrier. It has been found that the Coulomb interaction in the well and barrier forces the formation of localized states in the barrier region. The possibility of an insulator-metal transition in InSe/GaSe superlattice is predicted for modulation doping in the barrier and for a doping level n = 10 19cm-3. A decrease of the barrier height has been found for modulation doping in the well.

  15. Electronic structure and localized states in a model amorphous silicon

    NASA Astrophysics Data System (ADS)

    Allan, G.; Delerue, C.; Lannoo, M.

    1998-03-01

    The electronic structure of a model amorphous silicon (a-Si) represented by a supercell of 4096 silicon atoms [B.R. Djordjevic, M.F. Thorpe, and F. Wooten, Phys. Rev. B 52, 5685 (1995)] and of a model hydrogenated amorphous silicon (a-Si:H) that we have built from the a-Si model are calculated in the tight-binding approximation. The band edges near the gap are characterized by exponential tails of localized states induced mainly by the variations in bond angles. The spatial localization of the states is compared between a-Si and a-Si:H. Comparison with experiments suggests that the structural models give good descriptions of the amorphous materials.

  16. Semiclassical dynamics of electron wave packet states with phase vortices.

    PubMed

    Bliokh, Konstantin Yu; Bliokh, Yury P; Savel'ev, Sergey; Nori, Franco

    2007-11-09

    We consider semiclassical higher-order wave packet solutions of the Schrödinger 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) variant Planck's over 2pil (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.

  17. Detection of pulsed neutrons with solid-state electronics

    NASA Astrophysics Data System (ADS)

    Chatzakis, J.; Rigakis, I.; Hassan, S. M.; Clark, E. L.; Lee, P.

    2016-09-01

    Measurements of the spatial and time-resolved characteristics of pulsed neutron sources require large area detection materials and fast circuitry that can process the electronic pulses readout from the active region of the detector. In this paper, we present a solid-state detector based on the nuclear activation of materials by neutrons, and the detection of the secondary particle emission of the generated radionuclides’ decay. The detector utilizes a microcontroller that communicates using a modified SPI protocol. A solid-state, pulse shaping filter follows a charge amplifier, and it is designed as an inexpensive, low-noise solution for measuring pulses measured by a digital counter. An imaging detector can also be made by using an array of these detectors. The system can communicate with an interface unit and pass an image to a personal computer.

  18. 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.

  19. 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

  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. Benchmarking electronic-state excitation cross sections for electron-N{sub 2} collisions

    SciTech Connect

    Kato, Hidetoshi; Suzuki, Daisuke; Ohkawa, Mizuha; Hoshino, Masamitsu; Tanaka, Hiroshi; Campbell, Laurence; Brunger, Michael J.

    2010-04-15

    We report differential cross sections for electron impact excitation of the a {sup 1{Pi}}{sub g}, C {sup 3{Pi}}{sub u}, E {sup 3{Sigma}}{sub g}{sup +}, a{sup ''} {sup 1{Sigma}}{sub g}{sup +}, b {sup 1{Pi}}{sub u}, c{sub 3} {sup 1{Pi}}{sub u}, o{sub 3} {sup 1{Pi}}{sub u}, b{sup '} {sup 1{Sigma}}{sub u}{sup +}, c{sub 4}{sup '} {sup 1{Sigma}}{sub u}{sup +}, G {sup 3{Pi}}{sub u}, and F {sup 3{Pi}}{sub u} electronic states in N{sub 2}. The incident electron energies are 20, 30, and 40 eV, while the scattered electron angles are 10 deg. and 20 deg. These kinematic conditions were specifically targeted in order to try and shed new light on the worrying discrepancies that exist in the literature for the a {sup 1{Pi}}{sub g}, C {sup 3{Pi}}{sub u}, E {sup 3{Sigma}}{sub g}{sup +}, and a{sup ''} {sup 1{Sigma}}{sub g}{sup +} cross sections, and in general the present measurements confirm that those from the more recent results of the University of California, Fullerton, and the Jet Propulsion Laboratory [M. A. Khakoo, P. V. Johnson, I. Ozkay, P. Yan, S. Trajmar, and I. Kanik, Phys. Rev. A 71, 062703 (2005); C. P. Malone, P. V. Johnson, I. Kanik, B. Ajdari, and M. A. Khakoo, Phys. Rev. A 79, 032704 (2009)] are reliable. In addition, we provide a rigorous cross-check for the remaining seven electronic states, where the only recent comprehensive study is from Khakoo and colleagues [Phys. Rev. A 77, 012704 (2008)]. Here, however, some of those cross sections are confirmed and others are not, suggesting that further work is still needed.

  2. Human health and ecological toxicity potentials due to heavy metal content in waste electronic devices with flat panel displays.

    PubMed

    Lim, Seong-Rin; Schoenung, Julie M

    2010-05-15

    Display devices such as cathode-ray tube (CRT) televisions and computer monitors are known to contain toxic substances and have consequently been banned from disposal in landfills in the State of California and elsewhere. New types of flat panel display (FPD) devices, millions of which are now purchased each year, also contain toxic substances, but have not previously been systematically studied and compared to assess the potential impact that could result from their ultimate disposal. In the current work, the focus is on the evaluation of end-of-life toxicity potential from the heavy metal content in select FPD devices with the intent to inform material selection and design-for-environment (DfE) decisions. Specifically, the metals antimony, arsenic, barium, beryllium, cadmium, chromium, cobalt, copper, lead, mercury, molybdenum, nickel, selenium, silver, vanadium, and zinc in plasma TVs, LCD (liquid crystal display) TVs, LCD computer monitors and laptop computers are considered. The human health and ecotoxicity potentials are evaluated through a life cycle assessment perspective by combining data on the respective heavy metal contents, the characterization factors in the U.S. EPA Tool for the Reduction and Assessment of Chemical and other environmental Impacts (TRACI), and a pathway and impact model. Principal contributors to the toxicity potentials are lead, arsenic, copper, and mercury. Although the heavy metal content in newer flat panel display devices creates less human health toxicity potential than that in CRTs, for ecological toxicity, the new devices are worse, especially because of the mercury in LCD TVs and the copper in plasma TVs.

  3. Measurement of WW and WZ production in the lepton plus heavy flavor jets final state at CDF

    SciTech Connect

    Leone, Sandra

    2016-11-16

    We present the CDF measurement of the diboson WW and WZ production cross section in a final state consistent with leptonic W decay and jets originating from heavy flavor quarks, based on the full Tevatron Run II dataset. The analysis of the di–jet invariant mass spectrum allows the observation of 3.7 sigma evidence for the combined production processes of either WW or WZ bosons. The different heavy flavor decay pattern of the W and Z bosons and the analysis of the secondary–decay vertex properties allow to independently measure the WW and WZ production cross section in a hadronic final state. The measured cross sections are consistent with the standard model predictions and correspond to signal significances of 2.9 and 2.1 sigma for WW and WZ production, respectively.

  4. Interaction of Pd electron states with adsorbed hydrogen

    NASA Astrophysics Data System (ADS)

    Solov'ev, S. M.; Pettenkofer, C.; Pronin, I. I.; Potekhina, N. D.; Petrov, V. N.

    2013-02-01

    Investigations of electrons excited into image states (IS) of Pd clusters and their interaction with adsorbed hydrogen using photoelectron (PE) spectroscopy with synchrotron radiation is presented. Pd clusters were deposited on pyrolytic graphite surfaces which were used as inert substrates. PE spectra measured for Pd clusters at low photon energies show additional peaks at energies of ~ 4.7 and 5.25 eV that corresponds to Pd image states at energies EIS - Evac ≈ - 0.75 ± 0.1 eV and EIS - Evac ≈ - 0.2 ± 0.1 eV. After hydrogen adsorption on graphite with Pd clusters the H-induced features: positive peaks at energy - 2 eV, - 3.5 eV, - 7 eV and a small negative peak at - 4.6 eV, were observed in the valence band spectra of Pd below EF. While the peaks at - 3.5 eV and - 2 eV are the result of the formation of H-induced states in the SBZ the - 7 eV peak is due to strong interaction of Pd clusters with hydrogen producing a H―Pd bonding adsorbate state. It is proposed that a charge transfer from IS2 to Pd-H bond dominates over the H- anion neutralization via transfer of excess charge from H- to IS1.

  5. 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.

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

    DOE PAGES

    Khachatryan, Vardan

    2016-07-04

    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 atmore » $$\\sqrt{s}$$ = 8 TeV. The data correspond to an integrated luminosity of 19.7 fb-1. The search considers HH 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-tbar 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 $$\\sigma$$(gg → X) B(X → HH → $$b\\bar{b}b\\bar{b}$$) 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 $$\\Lambda_R$$ = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV.« less

  7. Electronic States of IC60BA and PC71BM

    NASA Astrophysics Data System (ADS)

    Sheng, Chun-Qi; Wang, Peng; Shen, Ying; Li, Wen-Jie; Zhang, Wen-Hua; Zhu, Jun-Fa; Lai, Guo-Qiao; Li, Hong-Nian

    2013-11-01

    We investigate the electronic states of IC60BA and PC71BM using first-principles calculations and photoelectron spectroscopy (PES) measurements. The energy level structures for all possible isomers are reported and compared with those of C60, C70 and PC61BM. The attachment of the side chains can raise the LUMO energies and decrease the HOMO-LUMO gaps, and thus helps to increase the power-conversion efficiency of bulk heterojunction solar cells. In the PES studies, we prepared IC60BA and PC71BM films on Si:H(111) substrates to construct adsorbate/substrate interfaces describable with the integer charge-transfer (ICT) model. Successful measurements then revealed that one of the most important material properties for an electron acceptor, the energy of the negative integer charge-transfer state (EICT-), is 4.31 eV below the vacuum level for PC71BM. The EICT- of IC60BA is smaller than 4.14 eV.

  8. Photodissociation of CCH: classical trajectory calculations involving seven electronic states.

    PubMed

    Apaydin, Gökşin; Fink, William H; Jackson, William M

    2004-11-15

    The photodissociation dynamics of ethynyl radical, C(2)H, involving seven electronic states is studied by classical trajectory calculations. Initial values of the trajectories are selected based on relative absorption intensities calculated by Mebel et al. The energies and the derivatives are interpolated by three-dimensional cubic spline interpolator using an extended data pool. Mean square errors and standard deviations in interpolation of energies for 450 data points are found to be in the range 3.1 x 10(-6)-1.4 x 10(-5) and 1.7 x 10(-3)-3.8 x 10(-3) hartrees, respectively. The photofragments of C(2) and H are produced mainly in the X (1)Sigma(g) (+), a (3)Pi(u), b (3)Sigma(g) (-), c (3)Sigma(u) (+), A (1)Pi(u), B (1)Delta(g) electronic states of C(2) as product. The avoided crossings do not appear to be in the main dissociation pathways. The internal distributions are in good accord with the experimental results where comparison is possible, suggesting that the fragmentation mechanism of C(2)H(2) into C(2) and H is a two step process involving C(2)H radical as an intermediate with a life time long enough to allow complete collection of the phase space in the experiments.

  9. Photodissociation of CCH: Classical trajectory calculations involving seven electronic states

    NASA Astrophysics Data System (ADS)

    Apaydın, Gökşin; Fink, William H.; Jackson, William M.

    2004-11-01

    The photodissociation dynamics of ethynyl radical, C2H, involving seven electronic states is studied by classical trajectory calculations. Initial values of the trajectories are selected based on relative absorption intensities calculated by Mebel et al. The energies and the derivatives are interpolated by three-dimensional cubic spline interpolator using an extended data pool. Mean square errors and standard deviations in interpolation of energies for 450 data points are found to be in the range 3.1×10-6-1.4×10-5 and 1.7×10-3-3.8×10-3 hartrees, respectively. The photofragments of C2 and H are produced mainly in the X 1Σg+, a 3Πu, b 3Σg-, c 3Σu+, A 1Πu, B 1Δg electronic states of C2 as product. The avoided crossings do not appear to be in the main dissociation pathways. The internal distributions are in good accord with the experimental results where comparison is possible, suggesting that the fragmentation mechanism of C2H2 into C2 and H is a two step process involving C2H radical as an intermediate with a life time long enough to allow complete collection of the phase space in the experiments.

  10. 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)

  11. Electronic states and spin-orbit splitting of lanthanum dimer

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Wu, Lu; Zhang, Chang-Hua; Krasnokutski, Serge A.; Yang, Dong-Sheng

    2011-07-01

    Lanthanum dimer (La2) was studied by mass-analyzed threshold ionization (MATI) spectroscopy and a series of multi-configuration ab initio calculations. The MATI spectrum exhibits three band systems originating from ionization of the neutral ground electronic state, and each system shows vibrational frequencies of the neutral molecule and singly charged cation. The three ionization processes are La2+ (a2∑g+) ← La2 (X1∑g+), La2+ (b2Π3/2, u) ← La2 (X1∑g+), and La2+ (b2Π1/2, u) ← La2 (X1∑g+), with the ionization energies of 39 046, 40 314, and 40 864 cm-1, respectively. The vibrational frequency of the X1Σg+ state is 207 cm-1, and those of the a2Σg+, b2Π3/2, u and b2Π1/2, u are 235.7, 242.2, and 240 cm-1. While X1Σg+ is the ground state of the neutral molecule, a2Σg+ and b2Πu are calculated to be the excited states of the cation. The spin-orbit splitting in the b2Πu ion is 550 cm-1. An X4Σg- state of La2+ was predicted by theory, but not observed by the experiment. The determination of a singlet ground state of La2 shows that lanthanum behaves differently from scandium and yttrium.

  12. Electronic spin state of iron in lower mantle perovskite

    SciTech Connect

    Li, J.; Struzhkin, V.; Mao, H.-k.; Shu, J.; Hemley, R.; Fei, Y.; Mysen, B.; Dera, P.; Parapenka, V.; Shen, G.

    2010-11-16

    The electronic spin state of iron in lower mantle perovskite is one of the fundamental parameters that governs the physics and chemistry of the most voluminous and massive shell in the Earth. We present experimental evidence for spin-pairing transition in aluminum-bearing silicate perovskite (Mg,Fe)(Si,Al)O{sub 3} under the lower mantle pressures. Our results demonstrate that as pressure increases, iron in perovskite transforms gradually from the initial high-spin state toward the final low-spin state. At 100 GPa, both aluminum-free and aluminum-bearing samples exhibit a mixed spin state. The residual magnetic moment in the aluminum-bearing perovskite is significantly higher than that in its aluminum-free counterpart. The observed spin evolution with pressure can be explained by the presence of multiple iron species and the occurrence of partial spin-paring transitions in the perovskite. Pressure-induced spin-pairing transitions in the perovskite would have important bearing on the magnetic, thermoelastic, and transport properties of the lower mantle, and on the distribution of iron in the Earth's interior. The lower mantle constitutes more than half of the Earth's interior by volume (1), and it is believed to consist predominantly (80-100%) of (Mg,Fe)(Si,Al)O{sub 3} perovskite (hereafter called perovskite), with up to 20% (Mg,Fe)O ferropericlase (2). The electronic spin state of iron has direct influence on the physical properties and chemical behavior of its host phase. Hence, knowledge on the spin state of iron is important for the interpretation of seismic observations, geochemical modeling, and geodynamic simulation of the Earth's deep interior (3, 4). Crystal field theory (4, 5) and band theory (6) predicted that a high-spin to low-spin transition would occur as a result of compression. To date, no experimental data exist on the spin sate of iron in Al-bearing perovskite. To detect possible spinpairing transition of iron in perovskite under the lower mantle

  13. 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.

  14. Differential cross sections for electron-impact excitation of the electronic states of pyrimidine

    NASA Astrophysics Data System (ADS)

    Brunger, Michael; Jones, Darryl; Bellm, Susan

    2012-06-01

    Pyrimidine (C4N2H4) is an important molecule, as it forms the basis of larger biomolecules, such as the DNA bases thymine, cytosine and uracil. There is a pressing demand for low-energy electron scattering data from such biological analogs in order to model radiation induced damage [1]. We therefore present the first measurements for absolute differential cross section data for low-energy electron-impact excitation of the electronic states of pyrimidine. The present measurements were performed using a crossed-beam apparatus [2] for incident electron energies ranging between 15 to 50eV while covering a 10 to 90^o angular range. Here the absolute scale has been determined through a normalisation to the recently measured elastic scattering differential cross section data for pyrimidine [3]. [1] F. Ferreira da Silva, D. Almeida, G. Martins, A. R. Milosavljevic, B. P. Marinkovic, S. V. Hoffmann, N. J. Mason, Y. Nunes, G. Garcia and P. Limao-Vieira, Phys Chem Chem Phys 12, 6717 (2010). [2] M. J. Brunger and P. J. O. Teubner, Phys Rev A 41, 1413 (1990). [3] P. Palihawadana, J. Sullivan, M. Brunger, C. Winstead, V. McKoy, G. Garcia, F. Blanco and S. Buckman, Phys Rev A 84, 062702 (2011).

  15. Design study of electron cyclotron resonance-ion plasma accelerator for heavy ion cancer therapy

    SciTech Connect

    Inoue, T. Sugimoto, S.; Sasai, K.; Hattori, T.

    2014-02-15

    Electron Cyclotron Resonance-Ion Plasma Accelerator (ECR-IPAC) device, which theoretically can accelerate multiple charged ions to several hundred MeV with short acceleration length, has been proposed. The acceleration mechanism is based on the combination of two physical principles, plasma electron ion adiabatic ejection (PLEIADE) and Gyromagnetic Autoresonance (GYRAC). In this study, we have designed the proof of principle machine ECR-IPAC device and simulated the electromagnetic field distribution generating in the resonance cavity. ECR-IPAC device consisted of three parts, ECR ion source section, GYRAC section, and PLEIADE section. ECR ion source section and PLEIADE section were designed using several multi-turn solenoid coils and sextupole magnets, and GYRAC section was designed using 10 turns coil. The structure of ECR-IPAC device was the cylindrical shape, and the total length was 1024 mm and the maximum diameter was 580 mm. The magnetic field distribution, which maintains the stable acceleration of plasma, was generated on the acceleration center axis throughout three sections. In addition, the electric field for efficient acceleration of electrons was generated in the resonance cavity by supplying microwave of 2.45 GHz.

  16. 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.

  17. Hamiltonian of a many-electron system with single-electron and electron-pair states in a two-dimensional periodic potential

    NASA Astrophysics Data System (ADS)

    Hai, Guo-Qiang; Peeters, François M.

    2015-01-01

    Based on the metastable electron-pair energy band in a two-dimensional (2D) periodic potential obtained previously by Hai and Castelano [J. Phys.: Condens. Matter 26, 115502 (2014)], we present in this work a Hamiltonian of many electrons consisting of single electrons and electron pairs in the 2D system. The electron-pair states are metastable of energies higher than those of the single-electron states at low electron density. We assume two different scenarios for the single-electron band. When it is considered as the lowest conduction band of a crystal, we compare the obtained Hamiltonian with the phenomenological model Hamiltonian of a boson-fermion mixture proposed by Friedberg and Lee [Phys. Rev. B 40, 6745 (1989)]. Single-electron-electron-pair and electron-pair-electron-pair interaction terms appear in our Hamiltonian and the interaction potentials can be determined from the electron-electron Coulomb interactions. When we consider the single-electron band as the highest valence band of a crystal, we show that holes in this valence band are important for stabilization of the electron-pair states in the system.

  18. Heavy metal monitoring, analysis and prediction in lakes and rivers: state of the art.

    PubMed

    Elzwayie, Adnan; Afan, Haitham Abdulmohsin; Allawi, Mohammed Falah; El-Shafie, Ahmed

    2017-03-29

    Several research efforts have been conducted to monitor and analyze the impact of environmental factors on the heavy metal concentrations and physicochemical properties of water bodies (lakes and rivers) in different countries worldwide. This article provides a general overview of the previous works that have been completed in monitoring and analyzing heavy metals. The intention of this review is to introduce the historical studies to distinguish and understand the previous challenges faced by researchers in analyzing heavy metal accumulation. In addition, this review introduces a survey on the importance of time increment sampling (monthly and/or seasonally) to comprehend and determine the rate of change of different parameters on a monthly and seasonal basis. Furthermore, suggestions are made for future research to achieve more understandable figures on heavy metal accumulation by considering climate conditions. Thus, the intent of the current study is the provision of reliable models for predicting future heavy metal accumulation in water bodies in different climates and pollution conditions so that water management can be achieved using intelligent proactive strategies and artificial neural network (ANN) techniques.

  19. Evaluating Electronic Couplings for Excited State Charge Transfer Based on Maximum Occupation Method ΔSCF Quasi-Adiabatic States.

    PubMed

    Liu, Junzi; Zhang, Yong; Bao, Peng; Yi, Yuanping

    2017-02-14

    Electronic couplings of charge-transfer states with the ground state and localized excited states at the donor/acceptor interface are crucial parameters for controlling the dynamics of exciton dissociation and charge recombination processes in organic solar cells. Here we propose a quasi-adiabatic state approach to evaluate electronic couplings through combining maximum occupation method (mom)-ΔSCF and state diabatization schemes. Compared with time-dependent density functional theory (TDDFT) using global hybrid functional, mom-ΔSCF is superior to estimate the excitation energies of charge-transfer states; moreover it can also provide good excited electronic state for property calculation. Our approach is hence reliable to evaluate electronic couplings for excited state electron transfer processes, which is demonstrated by calculations on a typical organic photovoltaic system, oligothiophene/perylenediimide complex.

  20. 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.

  1. Computer-simulation calculations of the electronic stopping of fast heavy charges by a classical harmonic oscillator

    SciTech Connect

    Jakas, M. M.; Perez de la Rosa, F. J.; Custidiano, E. R.

    2003-09-01

    The accuracy of Bohr's and more recent analytical calculations of the electronic stopping of heavy charges by a classical harmonic oscillator is analyzed. According to results in this paper, for |{xi}|{>=}100 ({xi} being the Bohr stopping parameter) the present simulations agree with previous theoretical calculations, whereas for smaller |{xi}| values, discrepancies are evident. In fact, for |{xi}|<100 the stopping cross section seems to be sensitive to the sign of the ion charge. The so-called Barkas effect is unambiguously observed and positively charged projectiles appear to have a larger stopping compared to that of negative ones at the same {xi}. Bohr's calculations, however, seem to reproduce the stopping of negative charges relatively well, but those of positive ions are consequently underestimated. By giving the electron an initial velocity, the so-called inner-shell effect on the stopping can be readily studied. The present simulations show that previous analytical predictions of this effect do not account for the present results.

  2. 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.

  3. 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

  4. 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.

  5. New computational approaches to the N-body problem with applications to electron cooling of heavy ion beams

    NASA Astrophysics Data System (ADS)

    Abeyratne, Pulukkuttige D. Sumana

    Thomas Jefferson National Accelerator Facility (JLab) has proposed a new Electron- Ion Collider, JLEIC. In this collider, a polarized electron beam and a counter rotating ion beam collide at the interaction point(s). A critical problem for the JLEIC collider is cooling the ion beam to ensure small emittance and to achieve high luminosity. Since electron cooling --a method of cooling 'hot' ion beams through Coulomb interactions with 'cold' electron beams--is one of the most effective cooling methods, it will be used by JLEIC. However, the most naive way of calculating Coulomb forces through the pair-wise method becomes infeasible even with the most high performing computers since the computational complexity grows O(N2), where N is the number of particles as large as 1011. In this dissertation, we have developed new computational tools and a high performance computer code that allows, for the first time, a particle-based simulation of realistic electron cooling scenarios of heavy ion beams. Our toolset, collectively referred to as the Particles High-Order Adaptive Dynamics (PHAD), contains three specific tools. The first tool, the adaptive multi-level Fast Multipole Method, reduces the computational cost of computing Coulomb forces to only O(N). Our platform supports particles of any complex distribution (2D or 3D). The second tool, the Picard iteration-based integrator, resolves close encounters of particles efficiently and accurately. Finally, the third tool, the Strang operator splitting, reduces the runtime while maintaining the accuracy. The high performance code is comprised of these three main components. Although, the proposed toolset is both precise and fast, completely simulating the electron cooling of the ion beam still takes a long time on a modern computer cluster due to the millions of small time steps that needs to be simulated. In order to overcome this challenge, we have developed an MPI-parallel high performance computer code to speed up our

  6. The role of sleepiness, sleep disorders, and the work environment on heavy-vehicle crashes in 2 Australian states.

    PubMed

    Stevenson, Mark R; Elkington, Jane; Sharwood, Lisa; Meuleners, Lynn; Ivers, Rebecca; Boufous, Soufiane; Williamson, Ann; Haworth, Narelle; Quinlan, Michael; Grunstein, Ron; Norton, Robyn; Wong, Keith

    2014-03-01

    Heavy-vehicle driving involves a challenging work environment and a high crash rate. We investigated the associations of sleepiness, sleep disorders, and work environment (including truck characteristics) with the risk of crashing between 2008 and 2011 in the Australian states of New South Wales and Western Australia. We conducted a case-control study of 530 heavy-vehicle drivers who had recently crashed and 517 heavy-vehicle drivers who had not. Drivers' crash histories, truck details, driving schedules, payment rates, sleep patterns, and measures of health were collected. Subjects wore a nasal flow monitor for 1 night to assess for obstructive sleep apnea. Driving schedules that included the period between midnight and 5:59 am were associated with increased likelihood of crashing (odds ratio = 3.42, 95% confidence interval: 2.04, 5.74), as were having an empty load (odds ratio = 2.61, 95% confidence interval: 1.72, 3.97) and being a less experienced driver (odds ratio = 3.25, 95% confidence interval: 2.37, 4.46). Not taking regular breaks and the lack of vehicle safety devices were also associated with increased crash risk. Despite the high prevalence of obstructive sleep apnea, it was not associated with the risk of a heavy-vehicle nonfatal, nonsevere crash. Scheduling of driving to avoid midnight-to-dawn driving and the use of more frequent rest breaks are likely to reduce the risk of heavy-vehicle nonfatal, nonsevere crashes by 2-3 times.

  7. 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).

  8. 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.

  9. Steady-state and transient electronic dynamics in granular metals

    NASA Astrophysics Data System (ADS)

    Chen, Wei

    In this thesis two very different approaches, steady state and transient, are taken to help understand the electronic dynamics in the nanogranular Cux(SiO2)1-x composite thin films. The electrical conductivity and thermopower are measured from 2 K to room temperature with the Cu volume fraction x varying from 1 down to 0.43. At low temperatures, a T dependence of the electrical conductivity is observed well above the percolation threshold due to the disorder-enhanced electron-electron interaction and as the metal-insulator transition is approached, the electrical conductivity assumes a T1/3 dependence. The thermopower is found to be small and rather insensitive to the degree of disorder in the system. It varies linearly with temperatures at both low and high temperatures. Annealing has considerable influence to the behavior of the electrical conductivity while introducing little changes to the thermopower. Femtosecond pump-probe experiments were performed on a series of Cu x(SiO2)1-x composite films with volume fraction x varying from 0.7 to 1.0 to study the reflectivity change DeltaR/R as a function of composition and temperature. It is discovered that DeltaR/R undergoes drastic changes as the metal content is lowered. Very small amount of SiO 2 inclusions can start to result in qualitatively different Delta R/R behavior from pure Cu. Changes in the dielectric constant of Cu are investigated and possible explanations for the DeltaR/R behaviors in the composite films are discussed.

  10. 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.

  11. Electron transport in multiterminal networks of Majorana bound states

    NASA Astrophysics Data System (ADS)

    Weithofer, Luzie; Recher, Patrik; Schmidt, Thomas L.

    2014-11-01

    We investigate electron transport through multiterminal networks hosting Majorana bound states (MBS) in the framework of full counting statistics. In particular, we apply our general results to T-shaped junctions of two Majorana nanowires. When the wires are in the topologically nontrivial regime, three MBS are localized near the outer ends of the wires, while one MBS is localized near the crossing point, and when the lengths of the wires are finite adjacent MBS can overlap. We propose a combination of current and cross-correlation measurements to reveal the predicted coupling of four Majoranas in a topological T junction. Interestingly, we show that the elementary transport processes at the central lead are different compared to the outer leads, giving rise to characteristic nonlocal signatures in electronic transport. We find quantitative agreement between our analytical model and numerical simulations of a tight-binding model. Using the numerical simulations, we discuss the effect of weak disorder on the current and the cross-correlation functions.

  12. Experimental Realization of Nearly Steady-State Toroidal Electron Plasmas

    NASA Astrophysics Data System (ADS)

    Stoneking, M. R.

    2008-11-01

    Non-neutral plasmas are routinely confined in the uniform magnetic field of a Penning-Malmberg trap for arbitrarily long times and approach thermal equilibrium. Theory predicts that dynamically stable and therefore long-lived equilibria exist for non-neutral plasmas confined in the curved, non-uniform field of a toroidal trap, but that ultimately thermal equilibrium states do not exist. On long timescales, the poloidal ExB rotation through the non-uniform toroidal magnetic field leads to magnetic pumping transport. A new experiment has, for the first time, demonstrated the existence of a stable, long-lived (i.e. nearly steady-state) toroidal equilibrium for pure electron plasmas and is poised to observe the magnetic pumping transport mechanism. Electron plasmas with densities of order 10^6 cm-3 are trapped in the Lawrence Non-neutral Torus II for several seconds. LNT II is a high aspect ratio (Ro/a 10), partially toroidal trap (a 270^o arc with Bo=670 G). The m=1 diocotron mode is launched and detected using isolated segments of a fully-sectored conducting boundary and its frequency is used to determine the total trapped charge as a function of time. The observed confinement time ( 3 s) approaches the theoretical limit ( 6 s) set by the magnetic pumping transport mechanism of Crooks and O'Neil. We also present equilibrium modeling and numerical simulation of the toroidal m=1 mode constrained by experimental data. Future work includes the identification of the dominant transport mechanisms via confinement scaling experiments and measurement of the m=2 mode frequency, and development of a strategy for making a transition to fully toroidal confinement. J.P. Marler and M.R. Stoneking, Phys. Rev. Lett. 100, 155001 (2008). S.M. Crooks and T.M. O'Neil, Phys Plamas 3, 2533 (1996).

  13. Achieving Stable Radiation Pressure Acceleration of Heavy Ions via Successive Electron Replenishment from Ionization of a High-Z Material Coating

    NASA Astrophysics Data System (ADS)

    Shen, X. F.; Qiao, B.; Chang, H. X.; Kar, S.; Zhou, C. T.; Borghesi, M.; He, X. T.

    2016-10-01

    Generation of monoenergetic heavy ion beams aroused more scientific interest in recent years. Radiation pressure acceleration (RPA) is an ideal mechanism for obtaining high-quality heavy ion beams, in principle. However, to achieve the same energy per nucleon (velocity) as protons, heavy ions undergo much more serious Rayleigh-Taylor-like (RT) instability and afterwards much worse Coulomb explosion due to loss of co-moving electrons. This leads to premature acceleration termination of heavy ions and very low energy attained in experiment. The utilization of a high-Z coating in front of the target may suppress the RT instability and Coulomb explosion by continuously replenishing the accelerating heavy ion foil with co-moving electrons due to its successive ionization under laser fields with Gaussian temporal and spatial profiles. Thus stable RPA can be realized. Two-dimensional and three-dimensional particles-in-cell simulations with dynamic ionization show that a monoenergetic Al13+ beam with peak energy 4.0GeV and particle number 1010 (charge > 20nC) can be obtained at intensity 1022 W/cm2. Supported by the NSF, Nos. 11575298 and 1000-Talents Program of China.

  14. 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

    2015-10-07

    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 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.

  15. 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.

  16. Conversion of electronic to magnonic spin current at a heavy-metal magnetic-insulator interface

    NASA Astrophysics Data System (ADS)

    Wang, Xi-guang; Li, Zhi-xiong; Zhou, Zhen-wei; Nie, Yao-zhuang; Xia, Qing-lin; Zeng, Zhong-ming; Chotorlishvili, L.; Berakdar, J.; Guo, Guang-hua

    2017-01-01

    Electronic spin current is convertible to magnonic spin current via the creation or annihilation of thermal magnons at the interface of a magnetic insulator and a metal with a strong spin-orbital coupling. So far this phenomenon was evidenced in the linear regime. Based on analytical and full-fledged numerical results for the nonlinear regime we demonstrate that the generated thermal magnons or magnonic spin current in the insulator is asymmetric with respect to the charge current direction in the metal and exhibits a nonlinear dependence on the charge current density, which is explained by the tuning effect of the spin Hall torque and the magnetization damping. The results are also discussed in light of, and are in line with, recent experiments pointing to a new way of nonlinear manipulation of spin with electrical means.

  17. 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…

  18. Heavy Flavor Physics in STAR

    NASA Astrophysics Data System (ADS)

    Videbæk, Flemming; STAR Collaboration

    2013-03-01

    In relativistic heavy-ion collisions at RHIC, heavy quarks are primarily created from initial hard scatterings. Since their large masses are not easily affected by the strong interaction with QCD medium they may carry information from the system at early stage. The interaction between heavy quarks and the medium is sensitive to the medium dynamics; therefore heavy quarks are suggested as an ideal probe to quantify the properties of the strongly interacting QCD matter. The STAR Collaboration should complete the Heavy Flavor Tracker (HFT) and the Muon Telescope Detector (MTD) upgrades by 2014. These detectors will greatly enhance the STAR physics capability to measure heavy quark collectivity and correlations using topologically reconstructed charmed hadrons and heavy quark decay electron-muon correlations. In addition, measurements of the quarkonium muon decay channels will enable us to separate Upsilon 1S from 2S and 3S states in p + p and A+A collisions. Selected STAR results on open charm and quarkonia production in p + p and Au+Au collisions at 200 GeV are presented. An overview of the upgrades, their expected performance and current status is presented.

  19. 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.

  20. Generation of high charge state metal ion beams by electron cyclotron resonance heating of vacuum arc plasma in cusp trap.

    PubMed

    Nikolaev, A G; Savkin, K P; Oks, E M; Vizir, A V; Yushkov, G Yu; Vodopyanov, A V; Izotov, I V; Mansfeld, D A

    2012-02-01

    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 μs) high power (up to 100 kW) microwave radiation at 37.5 GHz for the generation of highly charged heavy metal ion beams.

  1. Generation of high charge state metal ion beams by electron cyclotron resonance heating of vacuum arc plasma in cusp trapa)

    NASA Astrophysics Data System (ADS)

    Nikolaev, A. G.; Savkin, K. P.; Oks, E. M.; Vizir, A. V.; Yushkov, G. Yu.; Vodopyanov, A. V.; Izotov, I. V.; Mansfeld, D. A.

    2012-02-01

    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 μs) high power (up to 100 kW) microwave radiation at 37.5 GHz for the generation of highly charged heavy metal ion beams.

  2. Search for Heavy Particles Decaying into Electron-Positron Pairs in ppbar Collisions

    NASA Astrophysics Data System (ADS)

    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 (ρT), techniomega (ωT), and Z' particles, using the decay channels ρT,ωT,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 ppbar-->ρT,ωT,Z'-->e+e- as a function of the mass of the decaying particle. For certain model parameters, we exclude the existence of degenerate ρT and ωT 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.

  3. 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.

  4. 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.

  5. Bose-Einstein final state symmetrization for event generators of heavy ion collisions

    SciTech Connect

    Wiedemann, U.A.; Heinz, U.; Ellis, J.; Geiger, K.

    1998-12-01

    The current relativistic heavy ion program at CERN and BNL aims at investigating the equilibration properties of hadronic matter at extreme temperatures and densities where quarks and gluons are expected to be the physically relevant degrees of freedom for particle production processes. The theoretical discussion of these collision systems is complicated by their mesoscopic character. They are not sufficiently small to allow for an analytical description in terms of elementary processes. They are not sufficiently large to take a description in terms of macroscopic observables for granted. Even if simple thermodynamically of hydrodynamically inspired models account for the data, the task remains to understand the microscopic origin of their success, and to establish to what extent such an agreement is necessary or accidental. The authors discuss algorithms which allow to calculate identical two-particle correlations from numerical simulations of relativistic heavy ion collisions. A toy model is used to illustrate their properties.

  6. Berezinskii-Kosterlitz-Thouless transition to the superconducting state of heavy-fermion superlattices.

    PubMed

    She, Jian-Huang; Balatsky, Alexander V

    2012-08-17

    We propose an explanation of the superconducting transitions discovered in the heavy-fermion superlattices by Mizukami et al. [Nature Phys. 7, 849 (2011)] in terms of Berezinskii-Kosterlitz-Thouless (BKT) transition. We observe that the effective mass mismatch between the heavy-fermion superconductor and the normal metal regions provides an effective barrier that enables quasi-2D superconductivity in such systems. We show that the resistivity data, both with and without magnetic field, are consistent with BKT transition. Furthermore, we study the influence of a nearby magnetic quantum critical point on the vortex system and find that the vortex core energy can be significantly reduced due to magnetic fluctuations. Further reduction of the gap with decreasing number of layers is understood as a result of pair breaking effect of Yb ions at the interface.

  7. 75 FR 983 - Cross-Media Electronic Reporting Rule State Approved Program Revision/Modification Approvals...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-07

    ... 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 of...@epa.gov . SUPPLEMENTARY INFORMATION: On October 13, 2005, the final Cross-Media Electronic...

  8. 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

    ...] [FR Doc No: 2010-28651] ENVIRONMENTAL PROTECTION AGENCY [FRL-9226-9] Cross-Media Electronic Reporting...-Media Electronic Reporting, of the State of Hawaii's request to revise certain of its EPA-authorized...-Media Electronic Reporting Rule (CROMERR) was published in the Federal Register (70 FR 59848)...

  9. Pseudopotential and full-electron DFT calculations of thermodynamic properties of electrons in metals and semiempirical equations of state.

    PubMed

    Levashov, P R; Sin'ko, G V; Smirnov, N A; Minakov, D V; Shemyakin, O P; Khishchenko, K V

    2010-12-22

    In the present work, we compare the thermal contribution of electrons to thermodynamic functions of metals in different models at high densities and electron temperatures. One of the theoretical approaches, the full-potential linear-muffin-tin-orbital method, treats all electrons in the framework of density functional theory (DFT). The other approach, VASP, uses projector-augmented-wave pseudopotentials for the core electrons and considers the valent electrons also in the context of DFT. We analyze the limitations of the pseudopotential approach and compare the DFT results with a finite-temperature Thomas-Fermi model and two semiempirical equations of state.

  10. 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

  11. 77 FR 58131 - Cross-Media Electronic Reporting: Authorized Program Revision Approval, State of Mississippi

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-19

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY Cross-Media Electronic Reporting: Authorized Program Revision Approval, State of Mississippi... . SUPPLEMENTARY INFORMATION: On October 13, 2005, the final Cross-Media Electronic Reporting Rule (CROMERR)...

  12. 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.

  13. Study of heavy ion range in different solid state nuclear track detector materials

    NASA Astrophysics Data System (ADS)

    Diwan, P. K.; Singh, Lakhwant; Singh, Gurinder; Kumar, Shyam

    2000-03-01

    The range of several heavy ions as 238U, 208Pb, 197Au, 139La, 58Ni and 56Fe in sodalime glass; 197Au and 58Ni in muscovite mica and Lexan polycarbonate; 209Bi and 197Au in CR-39 have been determined experimentally. The calculations of range for these projectile-target combinations have been made using the Benton and Henke [10], Mukherjee and Nayak [11], Ziegler et al. [12] and Hubert et al. [14] semiempirical formulations. Finally a comparison has been made with the experimental results.

  14. 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.

  15. Implementation of Inverse Photoelectron Spectroscopy for Measuring the Empty Electronic States of Metal Oxide Surfaces

    DTIC Science & Technology

    2014-11-05

    and initial results on oxidized zirconium have been performed. (a) Papers published in peer-reviewed journals (N/A for none) Enter List of papers...the electronic states of the surface with changes in the photoluminescence spectrum. The results of some of our first experiments on zirconium ...clean” zirconium oxide. The occupied valence electronic states are mainly composed of oxygen 2p electrons. The unoccupied states are zirconium 4d

  16. Combined experimental and computational study of the recrystallization process induced by electronic interactions of swift heavy ions with silicon carbide crystals

    SciTech Connect

    Debelle, Aurelien; Backman, Marie; Thome, Lionel; Weber, William J; Toulemonde, Marcel; Mylonas, Stamatis; Boulle, Alexandre; Pakarinen, Olli H; Juslin, Niklas; Djurabekova, Flyura; Nordlund, Kai; Garrido, Frederico; Chaussende, Didier

    2012-01-01

    The healing effect of intense electronic energy deposition arising during swift heavy ion (SHI) irradiation is demonstrated in the case of 3C-SiC damaged by nuclear energy deposition. Experimental (ion channeling experiments) and computational (molecular dynamics simulations) studies provide consistent indications of disorder decrease after SHI irradiation. Furthermore, both methods establish that SHI-induced recrystallization takes place at amorphous-crystalline interfaces. The recovery process is unambiguously accounted for by the thermal spike phenomenon.

  17. Pilot study on the internal exposure to heavy metals of informal-level electronic waste workers in Agbogbloshie, Accra, Ghana.

    PubMed

    Wittsiepe, Jürgen; Feldt, Torsten; Till, Holger; Burchard, Gerd; Wilhelm, Michael; Fobil, Julius N

    2017-01-01

    Informal-level electronic waste (e-waste)-processing activities are performed at hotspots in developing countries such as India, China, and Ghana. These activities increase the ambient burden of heavy metals and contribute to the toxic exposure of the general population. However, few data exist on the internal exposure of populations involved in these informal activities and in close contact with fumes from the direct combustion of electronic waste products in these countries. Therefore, in a cross-sectional study design, we analyzed blood, urine, and hair samples from 75 e-waste workers residing in and/or working on a large e-waste recycling site in Agbogbloshie, Accra, Ghana, and compared the results against those of 40 individuals living in a suburb of Accra without direct exposure to e-waste recycling activities. A comparative analysis using the Mann-Whitney U test showed significantly higher median concentrations of blood lead (88.5 vs. 41.0 μg/l, p < 0.001), cadmium (0.12 vs. 0.10 μg/gcrea, p = 0.023), chromium (0.34 vs. 0.23 μg/gcrea, p < 0.001), and nickel (3.18 vs. 2.03 μg/gcrea, p < 0.001) in the urine of e-waste workers than those of controls. There was no difference in blood cadmium concentrations between the groups (0.51 vs. 0.57 μg/l, p = 0.215) or in urine mercury levels (0.18 vs. 0.18 μg/gcrea, p = 0.820). Hair mercury levels were higher in the controls than in the e-waste workers (0.43 vs. 0.72, p < 0.001). We compared our data with those from European populations, specifically using the German reference values, and found that the internal concentrations of the participants exceeded the German reference values in 59.3 vs. 3.1% (e-waste workers vs. controls) for blood lead, 56.9 vs. 52.5% for urine nickel, 22.2 vs. 20.0% for urine chromium, and 17.8 vs. 62.2% for hair mercury. In particular, the high blood lead levels of up to several hundred micrograms per liter are a cause for concern because many of the workers in

  18. Two-electron bound states near a Coulomb impurity in gapped graphene

    NASA Astrophysics Data System (ADS)

    De Martino, Alessandro; Egger, Reinhold

    2017-02-01

    We formulate and solve the perhaps simplest two-body bound-state problem for interacting Dirac fermions in two spatial dimensions. A two-body bound state is predicted for gapped graphene monolayers in the presence of weakly repulsive electron-electron interactions and a Coulomb impurity with charge Z e >0 , where the most interesting case corresponds to Z =1 . We introduce a variational Chandrasekhar-Dirac spinor wave function and show the existence of at least one bound state. This state leaves clear signatures accessible by scanning tunneling microscopy. One may thereby obtain direct information about the strength of electron-electron interactions in graphene.

  19. 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.

  20. 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.

  1. 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.

  2. 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,…

  3. STIR: Novel Electronic States by Gating Strongly Correlated Materials

    DTIC Science & Technology

    2016-03-01

    electron behavior which could be modulated by gating: spin liquids (e.g. a layered Sodium Iridate compound) and multiferroics (e.g. Bismuth Ferrite). We...electron behavior which could be modulated by gating: spin liquids (e.g. a layered Sodium Iridate compound) and multiferroics (e.g. Bismuth Ferrite

  4. 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

  5. Nonclassical properties of electronic states of aperiodic chains in a homogeneous electric field

    NASA Astrophysics Data System (ADS)

    Spisak, B. J.; Wołoszyn, M.

    2009-07-01

    The electronic energy levels of one-dimensional aperiodic systems driven by a homogeneous electric field are studied by means of a phase-space description based on the Wigner distribution function. The formulation provides physical insight into the quantum nature of the electronic states for the aperiodic systems generated by the Fibonacci and Thue-Morse sequences. The nonclassical parameter for electronic states is studied as a function of the magnitude of homogeneous electric field to achieve the main result of this work, which is to prove that the nonclassical properties of the electronic states in the aperiodic systems determine the transition probability between electronic states in the region of anticrossings. The localization properties of electronic states and the uncertainty product of momentum and position variables are also calculated as functions of the electric field.

  6. Excited state electron transfer after visible light absorption by the Co(I) state of vitamin B12.

    PubMed

    Achey, Darren; Brigham, Erinn C; DiMarco, Brian N; Meyer, Gerald J

    2014-11-11

    The first example of excited state electron transfer from cob(I)alamin is reported herein. Vitamin B12 was anchored to a mesoporous TiO2 thin film and electrochemically reduced to the cob(I)alamin form. Pulsed laser excitation resulted in rapid excited state electron transfer, ket > 10(8) s(-1), followed by microsecond interfacial charge recombination to re-form cob(I)alamin. The supernucleophilic cob(I)alamin was found to be a potent photoreductant. The yield of excited state electron transfer was found to be excitation wavelength dependent. The implications of this dependence are discussed.

  7. Electron transport in micro to nanoscale solid state networks

    NASA Astrophysics Data System (ADS)

    Fairbanks, Matthew Stetson

    This dissertation focuses on low-dimensional electron transport phenomena in devices ranging from semiconductor electron 'billiards' to semimetal atomic clusters to gold nanoparticles. In each material system, the goal of this research is to understand how carrier transport occurs when many elements act in concert. In the semiconductor electron billiards, magnetoconductance fluctuations, the result of electron quantum interference within the device, are used as a probe of electron transport through arrays of one, two, and three connected billiards. By combining two established analysis techniques, this research demonstrates a novel method for determining the quantum energy level spacing in each of the arrays. That information in turn shows the extent (and limits) of the phase-coherent electron wavefunction in each of the devices. The use of the following two material systems, the semimetal atomic clusters and the gold nanoparticles, is inspired by the electron billiard results. First, the output of the simple, rectangular electron billiards, the magnetoconductance fluctuations, is quite generally found to be fractal. This research addresses the question of what output one might expect from a device with manifestly fractal geometry by simulating the electrical response of fractal resistor networks and by outlining a method to implement such devices in fractal aggregates of semimetal atomic clusters. Second, in gold nanoparticle arrays, the number of array elements can increase by orders of magnitude over the billiard arrays, all with the potential to stay in a similar, phase-coherent transport regime. The last portion of this dissertation details the fabrication of these nanoparticle-based devices and their electrical characteristics, which exhibit strong evidence for electron transport in the Coulomb-blockade regime. A sketch for further 'off-blockade' experiments to realize magnetoconductance fluctuations, i.e. phase-coherent electron phenomena, is presented.

  8. Triply heavy tetraquark states with the QQbar{Q}bar{q} configuration

    NASA Astrophysics Data System (ADS)

    Chen, Kan; Liu, Xiang; Liu, Yan-Rui; Wu, Jing; Zhu, Shi-Lin

    2017-01-01

    In the framework of the color-magnetic interaction, we systematically investigate the mass splittings of the QQbar{Q}bar{q} tetraquark states and estimate their rough masses in this work. These systems include the explicitly exotic states ccbar{b}bar{q} and bbbar{c}bar{q} and the hidden exotic states ccbar{c}bar{q}, cbbar{b}bar{q}, bcbar{c}bar{q}, and bbbar{b}bar{q}. If a state around the estimated mass region can be observed, its nature as a genuine tetraquark is favored. The strong decay patterns shown here will be helpful to the experimental search for these exotic states.

  9. The current state of electronic consultation and electronic referral systems in Canada: an environmental scan.

    PubMed

    Liddy, Clare; Hogel, Matthew; Blazkho, Valerie; Keely, Erin

    2015-01-01

    Access to specialist care is a point of concern for patients, primary care providers, and specialists in Canada. Innovative e-health platforms such as electronic consultation (eConsultation) and referral (eReferral) can improve access to specialist care. These systems allow physicians to communicate asynchronously and could reduce the number of unnecessary referrals that clog wait lists, provide a record of the patient's journey through the referral system, and lead to more efficient visits. Little is known about the current state of eConsultation and eReferral in Canada. The purpose of this work was to identify current systems and gain insight into the design and implementation process of existing systems. An environmental scan approach was used, consisting of a systematic and grey literature review, and targeted semi-structured key informant interviews. Only three eConsultation/eReferral systems are currently in operation in Canada. Four themes emerged from the interviews: eReferral is an end goal for those provinces without an active eReferral system, re-organization of the referral process is a necessity prior to automation, engaging the end-user is essential, and technological incompatibilities are major impediments to progress. Despite the acknowledged need to improve the referral system and increase government spending on health information technology, eConsultation and eReferral systems remain scarce as Canada lags behind the rest of the developed world.

  10. Diagnostics of many-particle electronic states: non-stationary currents and residual charge dynamics

    NASA Astrophysics Data System (ADS)

    Maslova, N. S.; Mantsevich, V. N.; Arseyev, P. I.

    2017-01-01

    We propose the method for identifying many particle electronic states in the system of coupled quantum dots (impurities) with Coulomb correlations. We demonstrate that different electronic states can be distinguished by the complex analysis of localized charge dynamics and non-stationary characteristics. We show that localized charge time evolution strongly depends on the properties of initial state and analyze different time scales in charge kinetics for initially prepared singlet and triplet states. We reveal the conditions for existence of charge trapping effects governed by the selection rules for electron transitions between the states with different occupation numbers.

  11. 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.

  12. 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.

  13. In vivo ingestion of heavy metal particles of Se, Hg and W by murine macrophages. A study using scanning electron microscopy coupled with X-ray microanalysis.

    PubMed

    Cherdwongcharoensuk, Duangrudee; Cunha, Elisabete M; Upatham, Suchart; Pereira, António Sousa; Oliveira, Maria João R; Aguas, Artur P

    2002-09-01

    Several heavy metals that are currently employed in industry may become polluters of work and natural environments. As particulate matter, heavy metals are suitable for entering the human body through the respiratory and digestive systems. They often end up inside phagocytes; the size of the microscopic particles modulates both their phagocytosis, and the physiology of macrophages. Here we have adopted an experimental model to investigate the ingestion of particles of three industrial heavy metals (Se, Hg, W) by murine peritoneal macrophages in vivo. The phagocytes were studied by scanning electron microscopy coupled with X-ray elemental microanalysis (SEM-XRM), a method that allows specific identification of Se, W and Hg in cells at high resolution. We found that Hg that was taken up by macrophages was organized into small, round particles (0.31 +/- 0.14 microm). This was in contrast with the larger size of intracellular particles of Se (2.37 +/- 1.84 microm) or W (1.75 +/- 1.34 microm). Ingested particles of Se and W, but not Hg, often caused bulging of the cell surface of macrophages. We conclude that particulate matters of Se, W and Hg are organized in particles of different size inside macrophages. This size difference is likely to be associated with distinct phlogistic activities of these heavy metals, Se and W causing a milder inflammatory reaction than Hg.

  14. Low charge state heavy ion production with sub-nanosecond laser

    SciTech Connect

    Kanesue, T. Okamura, M.; Kumaki, M.; Ikeda, S.

    2016-02-15

    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.

  15. 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.

  16. 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.

  17. 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.

  18. Acid-base chemistry in the gas phase: The trans-1-naphtholṡNH3 complex in its S0 and S1 electronic states

    NASA Astrophysics Data System (ADS)

    Humphrey, Susan J.; Pratt, David W.

    1996-06-01

    We deduce information about the dynamics of a proton transfer reaction between an acid and a base. Our probe is the fully resolved S1←S0 fluorescence excitation spectrum of the 1:1 complex of 1-naphthol and ammonia in the gas phase. Analysis of this spectrum shows that the complex is planar in both electronic states, with the NH3 forming a nearly linear hydrogen bond to the hydroxy hydrogen atom of 1-naphthol. The O-H...N heavy atom separation is R=2.86 Å and the barrier to rotation of the NH3 group about its C3 axis is V3=39.9 cm-1 in the S0 state. Excitation of the complex to its S1 state increases the acidity of 1-naphthol, decreases the heavy atom separation to R=2.72 Å, and increases the torsional barrier to V3=46.5 cm-1. Modeling these changes using the Lippincott-Schroeder potential for the hydrogen bond shows that the photoinitiated heavy atom motion produces a significant decrease in the barrier to proton transfer in the S1 state.

  19. 78 FR 38989 - New Policies and Procedural Requirements for Electronic Submission of State Plans, and Program...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-28

    ...:// extranet.acf.hhs.gov/oldcdocs/materials.html . DATES: Submit written or electronic comments on the policies...://extranet.acf.hhs.gov/oldcdocs/materials.html . Electronic Submission of Program Progress and Financial... Electronic Submission of State Plans, and Program and Financial Reporting Forms, for Mandatory Grant...

  20. Analysis of heavy-rain-producing elevated thunderstorms in the MO-KS-OK region of the United States

    NASA Astrophysics Data System (ADS)

    McCoy, Laurel

    Most elevated thunderstorms in the United States occur in the Midwest, with a maximum in eastern Kansas (Colman 1990a). Elevated thunderstorms are defined as thunderstorms that occur over a very stable surface boundary layer (Colman 1990b). They may be better defined as convection occurring over a stable layer near the surface, essentially cut off from surface-based instability (Corfidi et al. 2006). Elevated mesoscale convective systems produce 30-70% of the total rainfall during the warm season over the Central Plains (Moore et al. 2003). 1.1 Purpose Elevated thunderstorms are still not very well understood. Elevated convection can take a variety of forms, and can be very similar to surface-based convection. Corfidi et al. (2006) describe the challenge of finding the originating layer of parcels making up a convective cloud. Surface-based convection often incorporates elevated parcels, and elevated convection can bring surface parcels into its updraft. The distinction between the two types of storms can be defined by where most of the parcels originate. This becomes especially hard to distinguish as convection transitions from surface-based to elevated and vice-versa (Corfidi et al. 2006). Colman (1990a), in his study, used three criteria to delineate elevated thunderstorm station reports from surface-based thunderstorm station reports: 1) The observation must lie on the cold side of an analyzed front that shows a clear contrast in temperature, dew-point temperature, and wind. 2) The station's wind, temperature, and dew-point temperature must be qualitatively similar to the immediately surrounding values. 3) The surface air on the warm side of the analyzed front must have a higher equivalent potential temperature (thetae) than the air on the cold side of the front (Colman 1990a). These three criteria have been incorporated into several studies since for the evaluation of elevated convection (e.g., Grant 1995; Rochette and Moore 1996; Moore et al. 1998; Moore et

  1. Donor acceptor electronic couplings in π-stacks: How many states must be accounted for?

    NASA Astrophysics Data System (ADS)

    Voityuk, Alexander A.

    2006-04-01

    Two-state model is commonly used to estimate the donor-acceptor electronic coupling Vda for electron transfer. However, in some important cases, e.g. for DNA π-stacks, this scheme fails to provide accurate values of Vda because of multistate effects. The Generalized Mulliken-Hush method enables a multistate treatment of Vda. In this Letter, we analyze the dependence of calculated electronic couplings on the number of the adiabatic states included in the model. We suggest a simple scheme to determine this number. The superexchange correction of the two-state approximation is shown to provide good estimates of the electronic coupling.

  2. 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.

  3. Coherent-state description of free-electron lasers

    NASA Astrophysics Data System (ADS)

    Lee, Ching Tsung

    1990-12-01

    It is generally accepted that the overall performance of free-electron lasers (FEL) can be understood without quantum mechanics. However, there are features of FEL such as photon statistics which can only be described quantum-mechanically. Although the majority of quantum-mechanical studies of FEL are devoted to one-particle models, there are also many studies on many-body effects of FEL. Unfortunately, the mathematical derivations of these studies are so complicated that it is not easy to follow the developments with a clearer picture in mind. The origin of the problem is the quantum recoils of the electrons. So we try to gain a clearer picture of the many-body effects by making the recoilless approximation. A simple model of FEL consists of a beam of relativistic electrons propagating through a spatially periodic magnetostatic wiggler field. The resulting laser output is propagating along the same direction as that of the electron beam. Quantum-mechanical analysis of FEL are usually based on the Bambini-Renieri frame which moves in the same direction as the propagating laser beam with a relativistic speed so that: (1) the wiggler field appears almost as a plane-wave radiation, (2) the frequency of the wiggler field coincides with that of the laser, and (3) the electron motion is nonrelativistic. Although in reality the laser beam can only derive its energy at the expense of the kinetic energy of the electrons, it appears in the Bambini-Renieri frame as if the photons of the laser were scattered from the fictitious photons of the wiggler field by the electrons.

  4. Co-Assignment of the Molecular Vibrational Frequencies in Different Electronic States

    NASA Astrophysics Data System (ADS)

    Panchenko, Yurii; Abramenkov, Alexander

    2016-06-01

    Ultrafast electron diffraction experimental data for the structural parameters of molecules in excited electronic states are comparatively uncommon, hence these parameters are largely unknown. However, because differences between the molecular geometries of excited and ground electronic states cause differences in their experimental vibrational spectra it is important to establish a correspondence between the molecular vibrational frequencies in the ground state and those of the excited state of interest. The correct co-assignment of the experimental vibrational frequencies between two different electronic states of a molecule may be determined by the analog of the Duschinsky matrix D. This matrix D is defined as D = (LI)-1LII where LI and LII are the matrices of the vibrational modes of the two states of the molecule under investigation. They are obtained by solving the vibrational problems in the I and II electronic states, respectively. Choosing the dominant elements in columns of the D matrix and permuting these columns to arrange these elements along the diagonal of the transformed matrix Dast makes it possible to establish the correct co-assignment of the calculated frequencies in the two electronic states. The rows of Dast are for the vibrations in the I electronic state, whereas the columns are for vibrations in the II electronic state. The results obtained may be tested by analogous calculations of Dast for isotopologues. The feasibility of co-assignments of the vibrational frequencies in the ground and T_1 and S_1 excited electronic states are demonstrated for trans-C_2O_2F_2. The analogs of the Duschinsky matrix Dast were used to juxtapose the vibrational frequencies of this molecule calculated at the CASPT2/cc-pVTZ level in the S_0, T_1 and S_1 states. F. Duschinsky, Acta Physicochim. URSS, 7(4), 551-566 (1937). Yu. N. Panchenko, Vibrational spectroscopy, 68, 236-240 (2013).

  5. 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.

  6. The electronic excited states of green fluorescent protein chromophore models

    NASA Astrophysics Data System (ADS)

    Olsen, Seth Carlton

    We explore the properties of quantum chemical approximations to the excited states of model chromophores of the green fluorescent protein of A. victoria. We calculate several low-lying states by several methods of quantum chemical calculation, including state-averaged complete active space SCF (CASSCF) methods, time dependent density functional theory (TDDFT), equation-of motion coupled cluster (EOM-CCSD) and multireference perturbation theory (MRPT). Amongst the low-lying states we identify the optically bright pipi* state of the molecules and examine its properties. We demonstrate that the state is dominated by a single configuration function. We calculate zero-time approximations to the resonance Raman spectrum of GFP chromophore models, and assign published spectra based upon these.

  7. 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.

  8. Magnetic properties and electronic structures of R Ni B compounds where R is a heavy rare earth

    NASA Astrophysics Data System (ADS)

    Burzo, E.; Bucur, N.; Chioncel, L.; Rednic, V.

    2008-07-01

    Magnetic measurements were performed in the temperature range 4.2-300 K and fields up to 70 kOe on R3Ni7B2 compounds with R = Gd, Tb, Dy, Ho, Er. The Curie temperatures decrease from 38.5 K (Gd) to 7 K (Er). Band structure calculations show that nickel, at 0 K, has a very small magnetic polarization, oriented antiparallel to the rare-earth moment. The XPS measurements suggest the presence of unoccupied Ni3d states. The reciprocal susceptibilities follow a Curie-Weiss type behaviour. Effective nickel moments of 1.33 ± 0.25 µB were determined. The magnetic behaviour of nickel is analysed in models which take into account electron correlation effects in d bands.

  9. Search for heavy top quark partners with charge 5e/3 in the single lepton final state

    NASA Astrophysics Data System (ADS)

    Sagir, Sinan; CMS Collaboration

    2016-03-01

    A search is presented for a very heavy fermionic partner of the top quark with charge 5e/3 (X5 / 3), which is expected to decay into a top quark and a W boson. Events consistent with pair production of X5 / 3, where one of the four W bosons from the decays of X5 / 3 and top quarks decays leptonically, and all the other W bosons decay hadronically, are analyzed. The results from this semi-leptonic final state are then combined with same-sign dileptons signature to enhance the sensitivity. No excess of data above SM expectations is observed and 95 % CL upper limits on the X5 / 3 production cross section are set using the data corresponding to an integrated luminosity of 2.2 fb-1 collected by the CMS detector at center-of-mass energy of 13 TeV.

  10. 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.

  11. 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.

  12. Electron density dynamics in the electronic ground state: motion along the Kekulé mode of benzene.

    PubMed

    Schild, Axel; Choudhary, Deepanshu; Sambre, Vaibhav D; Paulus, Beate

    2012-11-26

    If the Born-Oppenheimer approximation is invoked for the description of chemical reactions, the electron density rearranges following the motion of the nuclei. Even though this approach is central to theoretical chemistry, the explicit time dependence of the electron density is rarely studied, especially if the nuclei are treated quantum mechanically. In this article, we model the motion of benzene along the Kekulé vibrational coordinate to simulate the nuclear dynamics and electron density dynamics in the electronic ground state. Details of the change of core, valence, and π electrons are determined and analyzed. We show how the pictures anticipated by drawing Lewis structures of the rearrangement correlate with the time-dependent quantum description of the process.

  13. State of the art of electronic personal dosimeters for neutrons

    NASA Astrophysics Data System (ADS)

    d'Errico, Francesco; Luszik-Bhadra, Marlies; Lahaye, Thierry

    2003-06-01

    Despite a widely recognised need, electronic devices for personal dosimetry of neutrons or mixed neutron-photon fields are still far less established than systems for photon or beta radiations. A large research project is in progress to evaluate different methods currently used or under development for electronic personal dosimetry in mixed neutron-photon fields. The study includes testing in calibration fields as well as in representative workplaces of the nuclear industry. This paper describes the commercial and laboratory systems under investigation and their response characteristics. These were determined so far with measurements using ISO standard monoenergetic beams up to 19 MeV at the PTB in Braunschweig, Germany.

  14. Utah Heavy Oil Program

    SciTech Connect

    J. Bauman; S. Burian; M. Deo; E. Eddings; R. Gani; R. Goel; C.K. Huang; M. Hogue; R. Keiter; L. Li; J. Ruple; T. Ring; P. Rose; M. Skliar; P.J. Smith; J.P. Spinti; P. Tiwari; J. Wilkey; K. Uchitel

    2009-10-20

    The Utah Heavy Oil Program (UHOP) was established in June 2006 to provide multidisciplinary research support to federal and state constituents for addressing the wide-ranging issues surrounding the creation of an industry for unconventional oil production in the United States. Additionally, UHOP was to serve as an on-going source of unbiased information to the nation surrounding technical, economic, legal and environmental aspects of developing heavy oil, oil sands, and oil shale resources. UHOP fulGilled its role by completing three tasks. First, in response to the Energy Policy Act of 2005 Section 369(p), UHOP published an update report to the 1987 technical and economic assessment of domestic heavy oil resources that was prepared by the Interstate Oil and Gas Compact Commission. The UHOP report, entitled 'A Technical, Economic, and Legal Assessment of North American Heavy Oil, Oil Sands, and Oil Shale Resources' was published in electronic and hard copy form in October 2007. Second, UHOP developed of a comprehensive, publicly accessible online repository of unconventional oil resources in North America based on the DSpace software platform. An interactive map was also developed as a source of geospatial information and as a means to interact with the repository from a geospatial setting. All documents uploaded to the repository are fully searchable by author, title, and keywords. Third, UHOP sponsored Give research projects related to unconventional fuels development. Two projects looked at issues associated with oil shale production, including oil shale pyrolysis kinetics, resource heterogeneity, and reservoir simulation. One project evaluated in situ production from Utah oil sands. Another project focused on water availability and produced water treatments. The last project considered commercial oil shale leasing from a policy, environmental, and economic perspective.

  15. Electron delocalization and aromaticity in low-lying excited states of archetypal organic compounds.

    PubMed

    Feixas, Ferran; Vandenbussche, Jelle; Bultinck, Patrick; Matito, Eduard; Solà, Miquel

    2011-12-14

    Aromaticity is a property usually linked to the ground state of stable molecules. Although it is well-known that certain excited states are unquestionably aromatic, the aromaticity of excited states remains rather unexplored. To move one step forward in the comprehension of aromaticity in excited states, in this work we analyze the electron delocalization and aromaticity of a series of low-lying excited states of cyclobutadiene, benzene, and cyclooctatetraene with different multiplicities at the CASSCF level by means of electron delocalization measures. While our results are in agreement with Baird's rule for the aromaticity of the lowest-lying triplet excited state in annulenes having 4nπ-electrons, they do not support Soncini and Fowler's generalization of Baird's rule pointing out that the lowest-lying quintet state of benzene and septet state of cyclooctatetraene are not aromatic.

  16. Electronic absorption and ground state structure of carotenoid molecules.

    PubMed

    Mendes-Pinto, Maria M; Sansiaume, Elodie; Hashimoto, Hideki; Pascal, Andrew A; Gall, Andrew; Robert, Bruno

    2013-09-26

    Predicting the complete electronic structure of carotenoid molecules remains an extremely complex problem, particularly in anisotropic media such as proteins. In this paper, we address the electronic properties of nine relatively simple carotenoids by the combined use of electronic absorption and resonance Raman spectroscopies. Linear carotenoids exhibit an excellent correlation between (i) the inverse of their conjugation chain length N, (ii) the energy of their S0 → S2 electronic transition, and (iii) the position of their ν1 Raman band (corresponding to the stretching mode of their conjugated C═C bonds). For cyclic carotenoids such as β-carotene, this correlation is also observed between the latter two parameters (S0 → S2 energy and ν1 frequency), whereas their "nominal" conjugation length N does not follow the same relationship. We conclude that β-carotene and cyclic carotenoids in general exhibit a shorter effective conjugation length than that expected from their chemical structure. In addition, the effect of solvent polarizability on these molecular parameters was investigated for four of the carotenoids used in this study. We demonstrate that resonance Raman spectroscopy can discriminate between the different effects underlying shifts in the S0 → S2 transition of carotenoid molecules.

  17. Heavy quark masses

    NASA Technical Reports Server (NTRS)

    Testa, Massimo

    1990-01-01

    In the large quark mass limit, an argument which identifies the mass of the heavy-light pseudoscalar or scalar bound state with the renormalized mass of the heavy quark is given. The following equation is discussed: m(sub Q) = m(sub B), where m(sub Q) and m(sub B) are respectively the mass of the heavy quark and the mass of the pseudoscalar bound state.

  18. NMR study of valence fluctuating state in rare-earth based materials with multi-4f electrons

    NASA Astrophysics Data System (ADS)

    Mito, Takeshi

    2013-02-01

    Intermetallic compounds containing rare-earth elements have been a focus of interest due to their variety of intriguing phenomena, such as heavy fermion, valence fluctuation, magnetism, and superconductivity. Nuclear magnetic resonance (NMR) has played an important role in uncovering electronic states in those rare-earth based materials at the microscopic level. Among them, while cerium based materials have been intensively studied, there are so far a little NMR investigations on materials containing other rare-earth elements, such as samarium, europium, ytterbium, and so on, in spite of their attractive properties. We have recently concentrated on investigating the valence fluctuating states in the compounds with multi-4f electron configurations by NMR. Intermediate valence compound SmB6 undergoes an insulator-metal transition at the critical pressure 6-10 GPa [1,2], accompanied by the occurrence of a long-range magnetic order. In order to investigate intimate relationships between the insulating gap-formation, valence change, and magnetization as a function of pressure, we have successfully performed 11B-NMR up to ˜6 GPa. In this talk, we shall also present the result on EuPtP which shows two valence transitions at 235 K and 190 K [3].

  19. 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…

  20. 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.

  1. Strongly separated pairs of core electrons in computed ground states of small molecules.

    PubMed

    Gottlieb, Alex D; Weishäupl, Rada M

    2013-03-01

    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.

  2. A multi-state fragment charge difference approach for diabatic states in electron transfer: Extension and automation

    NASA Astrophysics Data System (ADS)

    Yang, Chou-Hsun; Hsu, Chao-Ping

    2013-10-01

    The electron transfer (ET) rate prediction requires the electronic coupling values. The Generalized Mulliken-Hush (GMH) and Fragment Charge Difference (FCD) schemes have been useful approaches to calculate ET coupling from an excited state calculation. In their typical form, both methods use two eigenstates in forming the target charge-localized diabatic states. For problems involve three or four states, a direct generalization is possible, but it is necessary to pick and assign the locally excited or charge-transfer states involved. In this work, we generalize the 3-state scheme for a multi-state FCD without the need of manual pick or assignment for the states. In this scheme, the diabatic states are obtained separately in the charge-transfer or neutral excited subspaces, defined by their eigenvalues in the fragment charge-difference matrix. In each subspace, the Hamiltonians are diagonalized, and there exist off-diagonal Hamiltonian matrix elements between different subspaces, particularly the charge-transfer and neutral excited diabatic states. The ET coupling values are obtained as the corresponding off-diagonal Hamiltonian matrix elements. A similar multi-state GMH scheme can also be developed. We test the new multi-state schemes for the performance in systems that have been studied using more than two states with FCD or GMH. We found that the multi-state approach yields much better charge-localized states in these systems. We further test for the dependence on the number of state included in the calculation of ET couplings. The final coupling values are converged when the number of state included is increased. In one system where experimental value is available, the multi-state FCD coupling value agrees better with the previous experimental result. We found that the multi-state GMH and FCD are useful when the original two-state approach fails.

  3. A multi-state fragment charge difference approach for diabatic states in electron transfer: extension and automation.

    PubMed

    Yang, Chou-Hsun; Hsu, Chao-Ping

    2013-10-21

    The electron transfer (ET) rate prediction requires the electronic coupling values. The Generalized Mulliken-Hush (GMH) and Fragment Charge Difference (FCD) schemes have been useful approaches to calculate ET coupling from an excited state calculation. In their typical form, both methods use two eigenstates in forming the target charge-localized diabatic states. For problems involve three or four states, a direct generalization is possible, but it is necessary to pick and assign the locally excited or charge-transfer states involved. In this work, we generalize the 3-state scheme for a multi-state FCD without the need of manual pick or assignment for the states. In this scheme, the diabatic states are obtained separately in the charge-transfer or neutral excited subspaces, defined by their eigenvalues in the fragment charge-difference matrix. In each subspace, the Hamiltonians are diagonalized, and there exist off-diagonal Hamiltonian matrix elements between different subspaces, particularly the charge-transfer and neutral excited diabatic states. The ET coupling values are obtained as the corresponding off-diagonal Hamiltonian matrix elements. A similar multi-state GMH scheme can also be developed. We test the new multi-state schemes for the performance in systems that have been studied using more than two states with FCD or GMH. We found that the multi-state approach yields much better charge-localized states in these systems. We further test for the dependence on the number of state included in the calculation of ET couplings. The final coupling values are converged when the number of state included is increased. In one system where experimental value is available, the multi-state FCD coupling value agrees better with the previous experimental result. We found that the multi-state GMH and FCD are useful when the original two-state approach fails.

  4. Excited electronic states and spectroscopy of unsymmetrically substituted polyenes

    NASA Astrophysics Data System (ADS)

    Itoh, Takao

    2013-09-01

    α-Methyl-ω-phenylpolyenes, Me-(CH=CH)N-Ph, (MPPNs) with N = 2, 3, and 4 were synthesized. Fluorescence, absorption, and excitation spectra of MPPNs have been measured under different conditions along with those of β-methylstyrene. It is shown that there is a forbidden singlet (π, π*) excited state located at energies below the absorbing state for MPPNs with N = 3 and 4. Excitation energies of these polyenes are determined as a function of N. Quantitative analysis of the temperature dependence of the relative intensity of the fluorescence spectrum and its solvent shift behavior extract estimates of the various physical parameters that characterize excitation energies and excited-state dynamical behavior of MPPN with N = 3. The singlet excited states of the MPPNs were compared with those of the α,ω-diphenylpolyenes and α,ω-dimethylpolyenes.

  5. Excited electronic states and spectroscopy of unsymmetrically substituted polyenes.

    PubMed

    Itoh, Takao

    2013-09-07

    α-Methyl-ω-phenylpolyenes, Me-(CH=CH)N-Ph, (MPPNs) with N = 2, 3, and 4 were synthesized. Fluorescence, absorption, and excitation spectra of MPPNs have been measured under different conditions along with those of β-methylstyrene. It is shown that there is a forbidden singlet (π, π∗) excited state located at energies below the absorbing state for MPPNs with N = 3 and 4. Excitation energies of these polyenes are determined as a function of N. Quantitative analysis of the temperature dependence of the relative intensity of the fluorescence spectrum and its solvent shift behavior extract estimates of the various physical parameters that characterize excitation energies and excited-state dynamical behavior of MPPN with N = 3. The singlet excited states of the MPPNs were compared with those of the α,ω-diphenylpolyenes and α,ω-dimethylpolyenes.

  6. Development of Solid State Electronics for a Spark Chamber

    NASA Astrophysics Data System (ADS)

    Gross, Eisen; Gray, Frederick

    2013-04-01

    Spark chambers have been used to detect charged particles in physics since the early part of the 20^th century. This very crude method can still be very useful in a classroom, museum, or outreach setting to show evidence of such particles. Older electronics such as vacuum tubes and spark gaps have been still used in recent designs, but they are resource-consuming to maintain and are becoming difficult to procure. These designs also used obsolescent electronics for the discriminators in the trigger circuit. A new design will be presented that uses a fast high voltage transistor switch along with modern comparators and programmable logic. Lower trigger latency has been achieved than in the traditional design. The muon imaging efficiency will be presented.

  7. Characterization of the electronic states of the biological relevant SSNO molecule

    NASA Astrophysics Data System (ADS)

    Ayari, Tarek; Hochlaf, Majdi; Mogren Al-Mogren, Muneerah; Francisco, Joseph S.

    2017-02-01

    Using configuration interaction ab initio methods, we investigate the lowest electronic states of doublet and quartet spin multiplicities of SSNO where the one-dimensional cuts of the six-dimensional potential energy surfaces of these electronic states along the stretching and bending coordinates are computed. Mainly, these electronic states are found to be repulsive along the central SN distance. A high density of electronic states is computed even at low excitation energies that may favor their couplings. Therefore, the dynamics of the SSNO electronic states is expected to be very complex. We also characterized the bound electronic states spectroscopically where we derived their equilibrium structures and vibrational frequencies. Our calculations show the importance of taking into account of dynamical correlation, in addition to static correlation, for the accurate description of SSNO electronic excited states and more generally for those of R-NO molecular species. Finally, we highlighted the potential role of SSNO in light-induced NO delivery from SSNO related species in biological media.

  8. Quantum ballistic transport by interacting two-electron states in quasi-one-dimensional channels

    SciTech Connect

    Huang, Danhong; Gumbs, Godfrey; Abranyos, Yonatan; Pepper, Michael; Kumar, Sanjeev

    2015-11-15

    For quantum ballistic transport of electrons through a short conduction channel, the role of Coulomb interaction may significantly modify the energy levels of two-electron states at low temperatures as the channel becomes wide. In this regime, the Coulomb effect on the two-electron states is calculated and found to lead to four split energy levels, including two anticrossing-level and two crossing-level states. Moreover, due to the interplay of anticrossing and crossing effects, our calculations reveal that the ground two-electron state will switch from one anticrossing state (strong confinement) to a crossing state (intermediate confinement) as the channel width gradually increases and then back to the original anticrossing state (weak confinement) as the channel width becomes larger than a threshold value. This switching behavior leaves a footprint in the ballistic conductance as well as in the diffusion thermoelectric power of electrons. Such a switching is related to the triple spin degeneracy as well as to the Coulomb repulsion in the central region of the channel, which separates two electrons away and pushes them to different channel edges. The conductance reoccurrence region expands from the weak to the intermediate confinement regime with increasing electron density.

  9. Measurements and calculations of the Coulomb cross section for the production of direct electron pairs by energetic heavy nuclei in nuclear track emulsion

    NASA Technical Reports Server (NTRS)

    Derrickson, J. H.; Eby, P. B.; Fountain, W. F.; Parnell, T. A.; Dong, B. L.; Gregory, J. C.; Takahashi, Y.; King, D. T.

    1988-01-01

    Measurements and theoretical predictions of the Coulomb cross section for the production of direct electron pairs by heavy ions in emulsion have been performed. Nuclear track emulsions were exposed to the 1.8 GeV/amu Fe-56 beam at the Lawrence Berkeley Laboratory bevalac and to the 60 and 200 GeV/amu O-16 and the 200 GeV/amu S-32 beam at the European Center for Nuclear Research Super Proton Synchrotron modified to accelerate heavy ions. The calculations combine the Weizsacker-Williams virtual quanta method applicable to the low-energy transfers and the Kelner-Kotov relativistic treatment for the high-energy transfers. Comparison of the measured total electron pair yield, the energy transfer distribution, and the emission angle distribution with theoretical predictions revealed a discrepancy in the frequency of occurrence of the low-energy pairs (less than or = 10 MeV). The microscope scanning criteria used to identify the direct electron pairs is described and efforts to improve the calculation of the cross section for pair production are also discussed.

  10. 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.

  11. Development of the Experimental Setup Dedicated for Alpha, Gamma and Electron Spectroscopy of Heavy Nuclei at FLNR JINR

    SciTech Connect

    Yeremin, A.; Malyshev, O.; Popeko, A.; Lopez-Martens, A.; Hauschild, K.; Dorvaux, O.; Saro, S.; Pantelika, D.

    2010-04-30

    Various types of reactions and identification techniques were applied in the investigation of formation cross sections and decay properties of transuranium elements. The fusion--evaporation reactions with heavy targets, recoil--separation techniques and identification of nuclei by the parent--daughter generic coincidences with the known daughter-nuclei after implantation into position--sensitive detectors were the most successful tools for production and identification of the heaviest elements known presently. This technique may be further improved and presently it may be very promising for the identification of new elements, search for new isotopes and measurement of new decay data for the known nuclei.At the Flerov Laboratory of Nuclear Reactions (JINR, Dubna), investigations of the complete fusion reactions leading to the synthesis of heavy and superheavy nuclei with the use of heavy ion beams from a powerful U400 cyclotron have been an important part of the experimental program. It is planned to upgrade U400 cyclotron of the FLNR, to deliver beams with higher intensities and smooth variation of energies.New experimental set up, the velocity filter, is now developing for synthesis and studies of the decay properties of heavy nuclei. At the focal plane of the separator GABRIELA set up (alpha,beta,gamma detectors array) will be installed.

  12. Development of the Experimental Setup Dedicated for Alpha, Gamma and Electron Spectroscopy of Heavy Nuclei at FLNR JINR

    NASA Astrophysics Data System (ADS)

    Yeremin, A.; Malyshev, O.; Popeko, A.; Lopez-Martens, A.; Hauschild, K.; Dorvaux, O.; Saro, S.; Pantelika, D.

    2010-04-01

    Various types of reactions and identification techniques were applied in the investigation of formation cross sections and decay properties of transuranium elements. The fusion—evaporation reactions with heavy targets, recoil—separation techniques and identification of nuclei by the parent—daughter generic coincidences with the known daughter-nuclei after implantation into position—sensitive detectors were the most successful tools for production and identification of the heaviest elements known presently. This technique may be further improved and presently it may be very promising for the identification of new elements, search for new isotopes and measurement of new decay data for the known nuclei. At the Flerov Laboratory of Nuclear Reactions (JINR, Dubna), investigations of the complete fusion reactions leading to the synthesis of heavy and superheavy nuclei with the use of heavy ion beams from a powerful U400 cyclotron have been an important part of the experimental program. It is planned to upgrade U400 cyclotron of the FLNR, to deliver beams with higher intensities and smooth variation of energies. New experimental set up, the velocity filter, is now developing for synthesis and studies of the decay properties of heavy nuclei. At the focal plane of the separator GABRIELA set up (α,β,γ detectors array) will be installed.

  13. Quasi-One-Dimensional Electronic States Inside and Outside Helium-Plated Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Motta, M.; Galli, D. E.; Liebrecht, M.; Del Maestro, A.; Cole, M. W.

    2016-10-01

    About one-half a century ago, it was realized that electrons experience a repulsive barrier when approaching the surface of condensed phases of helium, hydrogen, and neon. This led to the proposal and subsequent observation of image-potential surface-bound electronic states, which exhibit intriguing quasi-two-dimensional behavior. In the present work, we report similar quasi-one-dimensional electronic states by exploring single-wall carbon nanotubes coated both inside and outside by thin helium films. Electrons near such structures are localized in the radial direction, but free to move along the nanotube axis. The many-body aspects of the system are discussed qualitatively.

  14. Electronic structure and chemical bonding in the lowest electronic states of TcN.

    PubMed

    Borin, Antonio Carlos; Gobbo, João Paulo

    2009-11-12

    Multiconfiguration second-order perturbation theory, with the inclusion of relativistic effects and spin-orbit coupling, was employed to investigate the nature of the ground and low-lying Lambda-S and Omega states of the TcN molecule. Spectroscopic constants, effective bond order, and potential energy curves for 13 low-lying Lambda-S states and 5 Omega states are given. The computed ground state of TcN is of Omega = 3 symmetry (R(e) = 1.605 A and omega(e) = 1085 cm(-1)), originating mainly from the (3)Delta Lambda-S ground state. This result is contrasted with the nature of the ground state for other VIIB transtion-metal mononitrides, including X(3)Sigma(-) symmetry for MnN and Omega = 0(+) symmetry for ReN, derived also from a X(3)Sigma(-) state.

  15. Changes of functional and effective connectivity in smoking replenishment on deprived heavy smokers: a resting-state FMRI study.

    PubMed

    Ding, Xiaoyu; Lee, Seong-Whan

    2013-01-01

    Previous researches have explored the changes of functional connectivity caused by smoking with the aid of fMRI. This study considers not only functional connectivity but also effective connectivity regarding both brain networks and brain regions by using a novel analysis framework that combines independent component analysis (ICA) and Granger causality analysis (GCA). We conducted a resting-state fMRI experiment in which twenty-one heavy smokers were scanned in two sessions of different conditions: smoking abstinence followed by smoking satiety. In our framework, group ICA was firstly adopted to obtain the spatial patterns of the default-mode network (DMN), executive-control network (ECN), and salience network (SN). Their associated time courses were analyzed using GCA, showing that the effective connectivity from SN to DMN was reduced and that from ECN/DMN to SN was enhanced after smoking replenishment. A paired t-test on ICA spatial patterns revealed functional connectivity variation in regions such as the insula, parahippocampus, precuneus, anterior cingulate cortex, supplementary motor area, and ventromedial/dorsolateral prefrontal cortex. These regions were later selected as the regions of interest (ROIs), and their effective connectivity was investigated subsequently using GCA. In smoking abstinence, the insula showed the increased effective connectivity with the other ROIs; while in smoking satiety, the parahippocampus had the enhanced inter-area effective connectivity. These results demonstrate our hypothesis that for deprived heavy smokers, smoking replenishment takes effect on both functional and effective connectivity. Moreover, our analysis framework could be applied in a range of neuroscience studies.

  16. Heavy-ion injector based on an electron cyclotron ion source for the superconducting linear accelerator of the Rare Isotope Science Project

    SciTech Connect

    Hong, In-Seok Kim, Yong-Hwan; Choi, Bong-Hyuk; Choi, Suk-Jin; Park, Bum-Sik; Jin, Hyun-Chang; Kim, Hye-Jin; Heo, Jeong-Il; Kim, Deok-Min; Jang, Ji-Ho

    2016-02-15

    The injector for the main driver linear accelerator of the Rare Isotope Science Project in Korea, has been developed to allow heavy ions up to uranium to be delivered to the inflight fragmentation system. The critical components of the injector are the superconducting electron cyclotron resonance (ECR) ion sources, the radio frequency quadrupole (RFQ), and matching systems for low and medium energy beams. We have built superconducting magnets for the ECR ion source, and a prototype with one segment of the RFQ structure, with the aim of developing a design that can satisfy our specifications, demonstrate stable operation, and prove results to compare the design simulation.

  17. Heavy-ion injector based on an electron cyclotron ion source for the superconducting linear accelerator of the Rare Isotope Science Project.

    PubMed

    Hong, In-Seok; Kim, Yong-Hwan; Choi, Bong-Hyuk; Choi, Suk-Jin; Park, Bum-Sik; Jin, Hyun-Chang; Kim, Hye-Jin; Heo, Jeong-Il; Kim, Deok-Min; Jang, Ji-Ho

    2016-02-01

    The injector for the main driver linear accelerator of the Rare Isotope Science Project in Korea, has been developed to allow heavy ions up to uranium to be delivered to the inflight fragmentation system. The critical components of the injector are the superconducting electron cyclotron resonance (ECR) ion sources, the radio frequency quadrupole (RFQ), and matching systems for low and medium energy beams. We have built superconducting magnets for the ECR ion source, and a prototype with one segment of the RFQ structure, with the aim of developing a design that can satisfy our specifications, demonstrate stable operation, and prove results to compare the design simulation.

  18. Measurement of electrons from semileptonic heavy-flavor hadron decays in pp collisions at s=2.76TeV

    DOE PAGES

    Abelev, B.; Adam, J.; Adamová, D.; ...

    2015-01-07

    The pT-differential production cross section of electrons from semileptonic decays of heavy-flavor hadrons has been measured at midrapidity in proton-proton collisions at √s = 2.76  TeV in the transverse momentum range 0.5 < pT < 12  GeV/c with the ALICE detector at the LHC. The analysis was performed using minimum bias events and events triggered by the electromagnetic calorimeter. Predictions from perturbative QCD calculations agree with the data within the theoretical and experimental uncertainties.

  19. Measurement of electrons from semileptonic heavy-flavor hadron decays in p p collisions at √{s }=2.76 TeV

    NASA Astrophysics Data System (ADS)

    Abelev, B.; Adam, J.; Adamová, D.; Aggarwal, M. M.; Agnello, M.; Agostinelli, A.; Agrawal, N.; Ahammed, Z.; Ahmad, N.; Ahmed, I.; Ahn, S. U.; Ahn, S. A.; Aimo, I.; Aiola, S.; Ajaz, M.; Akindinov, A.; Alam, S. N.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alici, A.; Alkin, A.; 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.; Arbor, N.; Arcelli, S.; Armesto, N.; Arnaldi, R.; Aronsson, T.; Arsene, I. C.; Arslandok, M.; Augustinus, A.; Averbeck, R.; Awes, T. C.; Azmi, M. D.; Bach, M.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldisseri, A.; Baltasar Dos Santos Pedrosa, F.; Baral, R. C.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartke, J.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batyunya, B.; Batzing, P. C.; Baumann, C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bellwied, R.; Belmont-Moreno, E.; Belmont, R.; Belyaev, V.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Berger, M. E.; 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.; Bjelogrlic, S.; Blanco, F.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bøggild, H.; Bogolyubsky, M.; Böhmer, F. V.; Boldizsár, L.; Bombara, M.; Book, J.; Borel, H.; Borissov, A.; Bossú, F.; Botje, M.; Botta, E.; Böttger, S.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Caffarri, D.; Cai, X.; Caines, H.; Calero Diaz, L.; Caliva, A.; Calvo Villar, E.; Camerini, P.; Carena, F.; Carena, W.; Castillo Castellanos, J.; Casula, E. A. R.; Catanescu, V.; Cavicchioli, C.; Ceballos Sanchez, C.; Cepila, J.; Cerello, P.; Chang, B.; Chapeland, S.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Chochula, P.; 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.; Cortese, P.; Cortés Maldonado, I.; Cosentino, M. R.; Costa, F.; Crochet, P.; Cruz Albino, R.; Cuautle, E.; Cunqueiro, L.; Dainese, A.; Dang, R.; Danu, A.; Das, D.; Das, I.; Das, K.; Das, S.; Dash, A.; Dash, S.; de, S.; Delagrange, H.; Deloff, A.; Dénes, E.; D'Erasmo, G.; de Caro, A.; de Cataldo, G.; de Cuveland, J.; de Falco, A.; de Gruttola, D.; De Marco, N.; de Pasquale, S.; de Rooij, R.; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; di Bari, D.; di Liberto, S.; di Mauro, A.; di Nezza, P.; Djuvsland, Ø.; Dobrin, A.; Dobrowolski, T.; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Dørheim, S.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Dutta Majumdar, A. K.; Ehlers, R. J.; Elia, D.; Engel, H.; Erazmus, B.; Erdal, H. A.; Eschweiler, D.; Espagnon, B.; Esposito, M.; Estienne, M.; Esumi, S.; Evans, D.; Evdokimov, S.; Fabris, D.; Faivre, J.; Falchieri, D.; Fantoni, A.; Fasel, M.; Fehlker, D.; Feldkamp, L.; Felea, D.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Floratos, E.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Frankenfeld, U.; Fuchs, U.; Furget, C.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gallio, M.; Gangadharan, D. R.; Ganoti, P.; Garabatos, C.; Garcia-Solis, E.; Gargiulo, C.; Garishvili, I.; Gerhard, J.; Germain, M.; Gheata, A.; Gheata, M.; Ghidini, B.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Gladysz-Dziadus, E.; Glässel, P.; Gomez Ramirez, A.; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Graczykowski, L. K.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Grosse-Oetringhaus, J. F.; Grossiord, J.-Y.; Grosso, R.; Guber, F.; Guernane, R.; Guerzoni, B.; Guilbaud, M.; Gulbrandsen, K.; Gulkanyan, H.; Gumbo, M.; Gunji, T.; Gupta, A.; Gupta, R.; Khan, K. H.; Haake, R.; Haaland, Ø.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Hanratty, L. D.; Hansen, A.; Harris, J. W.; Hartmann, H.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Heide, M.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Hess, B. A.; Hetland, K. F.; Hippolyte, B.; Hladky, J.; Hristov, P.; Huang, M.; Humanic, T. J.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Ilkiv, I.; Inaba, M.; Innocenti, G. M.; Ionita, C.; Ippolitov, M.; Irfan, M.; Ivanov, M.; Ivanov, V.; Jachołkowski, A.; Jacobs, P. M.; Jahnke, C.; Jang, H. J.; Janik, M. A.; Jayarathna, P. H. S. Y.; Jena, S.; Jimenez Bustamante, R. T.; Jones, P. G.; Jung, H.; Jusko, A.; Kadyshevskiy, V.; Kalcher, S.; Kalinak, P.; Kalweit, A.; Kamin, J.; Kang, J. H.; Kaplin, V.; Kar, S.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karpechev, E.; Kebschull, U.; Keidel, R.; Khan, M. M.; Khan, P.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Kileng, B.; Kim, B.; Kim, D. W.; Kim, D. J.; Kim, J. S.; Kim, M.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, J.; Klein-Bösing, C.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobdaj, C.; Köhler, M. K.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Konevskikh, A.; Kovalenko, V.; Kowalski, M.; Kox, S.; Koyithatta Meethaleveedu, G.; Kral, J.; Králik, I.; Kramer, F.; Kravčáková, A.; Krelina, M.; Kretz, M.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.; Kučera, V.; Kucheriaev, Y.; Kugathasan, T.; Kuhn, C.; Kuijer, P. G.; Kulakov, I.; Kumar, J.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kushpil, S.; Kweon, M. J.; Kwon, Y.; Ladron de Guevara, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; Lara, C.; Lardeux, A.; Lattuca, A.; La Pointe, S. L.; La Rocca, P.; Lea, R.; Leardini, L.; Lee, G. R.; Legrand, I.; Lehnert, J.; Lemmon, R. C.; Lenti, V.; Leogrande, E.; Leoncino, M.; León Monzón, I.; Lévai, P.; Li, S.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Ljunggren, H. M.; Lodato, D. F.; Loenne, P. I.; Loggins, V. R.; Loginov, V.; Lohner, D.; Loizides, C.; Lopez, X.; López Torres, E.; Lu, X.-G.; Luettig, P.; Lunardon, M.; Luparello, G.; Luzzi, C.; Ma, R.; Maevskaya, A.; Mager, M.; Mahapatra, D. P.; Mahmood, S. M.; Maire, A.; Majka, R. D.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manceau, L.; Manko, V.; Manso, F.; Manzari, V.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Marín, A.; Markert, C.; Marquard, M.; Martashvili, I.; Martin, N. A.; Martinengo, P.; Martínez, M. I.; Martínez García, G.; Martin Blanco, J.; Martynov, Y.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Massacrier, L.; Mastroserio, A.; Matyja, A.; Mayer, C.; Mazer, J.; Mazzoni, M. A.; Meddi, F.; Menchaca-Rocha, A.; Mercado Pérez, J.; Meres, M.; Miake, Y.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Mischke, A.; Mishra, A. N.; Miśkowiec, D.; Mitra, J.; Mitu, C. M.; Mlynarz, J.; Mohammadi, N.; Mohanty, B.; Molnar, L.; Montaño Zetina, L.; Montes, E.; Morando, M.; Moreira de Godoy, D. A.; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Mühlheim, D.; Muhuri, S.; Mukherjee, M.; Müller, H.; Munhoz, M. G.; Murray, S.; Musa, L.; Musinsky, J.; Nandi, B. K.; Nania, R.; Nappi, E.; Nattrass, C.; Nayak, K.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Nicassio, M.; Niculescu, M.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Nilsen, B. S.; Noferini, F.; Nomokonov, P.; Nooren, G.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Oh, S. K.; Okatan, A.; Olah, L.; Oleniacz, J.; Oliveira da Silva, A. C.; Onderwaater, J.; Oppedisano, C.; Ortiz Velasquez, A.; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Sahoo, P.; Pachmayer, Y.; Pachr, M.; Pagano, P.; Paić, G.; Painke, F.; Pajares, C.; Pal, S. K.; Palmeri, A.; Pant, D.; Papikyan, V.; Pappalardo, G. S.; Pareek, P.; Park, W. J.; Parmar, S.; Passfeld, A.; Patalakha, D. I.; Paticchio, V.; Paul, B.; Pawlak, T.; Peitzmann, T.; Pereira da Costa, H.; Pereira de Oliveira Filho, E.; Peresunko, D.; Pérez Lara, C. E.; Pesci, A.; Peskov, V.; Pestov, Y.; Petráček, V.; Petran, M.; Petris, M.; Petrovici, M.; Petta, C.; Piano, S.; Pikna, M.; Pillot, P.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; Płoskoń, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-Lerma, P. L. M.; Poghosyan, M. G.; Pohjoisaho, E. H. O.; Polichtchouk, B.; Poljak, N.; Pop, A.; Porteboeuf-Houssais, S.; Porter, J.; Potukuchi, B.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puddu, G.; Pujahari, P.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Rascanu, B. T.; Rathee, D.; Rauf, A. W.; Razazi, V.; Read, K. F.; Real, J. S.; Redlich, K.; Reed, R. J.; Rehman, A.; Reichelt, P.; Reicher, M.; Reidt, F.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Rettig, F.; Revol, J.-P.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Rivetti, A.; Rocco, E.; Rodríguez Cahuantzi, M.; Rodriguez Manso, A.; Røed, K.; Rogochaya, E.; Rohni, S.; Rohr, D.; Röhrich, D.; Romita, R.; Ronchetti, F.; Rosnet, P.; Rossi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Russo, R.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Sadovsky, S.; Šafařík, K.; Sahlmuller, B.; Sahoo, R.; Sahu, P. K.; Saini, J.; Sakai, S.; Salgado, C. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Sanchez Castro, X.; Sánchez Rodríguez, F. J.; Šándor, L.; Sandoval, A.; Sano, M.; Santagati, G.; Sarkar, D.; Scapparone, E.; Scarlassara, F.; Scharenberg, R. P.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schuchmann, S.; Schukraft, J.; Schulc, M.; Schuster, T.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Segato, G.; Seger, J. E.; Sekiguchi, Y.; Selyuzhenkov, I.; Seo, J.; Serradilla, E.; Sevcenco, A.; Shabetai, A.; Shabratova, G.; Shahoyan, R.; Shangaraev, A.; Sharma, N.; Sharma, S.; Shigaki, K.; Shtejer, K.; Sibiriak, Y.; Siddhanta, S.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Singaraju, R.; Singh, R.; Singha, S.; Singhal, V.; Sinha, B. C.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Skjerdal, K.; Slupecki, M.; Smirnov, N.; Snellings, R. J. M.; Søgaard, C.; Soltz, R.; Song, J.; Song, M.; Soramel, F.; Sorensen, S.; Spacek, M.; Sputowska, I.; Spyropoulou-Stassinaki, M.; Srivastava, B. K.; Stachel, J.; Stan, I.; Stefanek, G.; Steinpreis, M.; Stenlund, E.; Steyn, G.; Stiller, J. H.; Stocco, D.; Stolpovskiy, M.; Strmen, P.; Suaide, A. A. P.; Sugitate, T.; Suire, C.; Suleymanov, M.; Sultanov, R.; Šumbera, M.; Susa, T.; Symons, T. J. M.; Szabo, A.; Szanto de Toledo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Takahashi, J.; Tangaro, M. A.; Tapia Takaki, J. D.; Tarantola Peloni, A.; Tarazona Martinez, A.; Tarzila, M. G.; Tauro, A.; Tejeda Muñoz, G.; Telesca, A.; Terrevoli, C.; Thäder, J.; Thomas, D.; Tieulent, R.; Timmins, A. R.; Toia, A.; Torii, H.; Trubnikov, V.; Trzaska, W. H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ulery, J.; Ullaland, K.; Uras, A.; Usai, G. L.; Vajzer, M.; Vala, M.; Valencia Palomo, L.; Vallero, S.; Vande Vyvre, P.; Vannucci, L.; van der Maarel, J.; van Hoorne, J. W.; van Leeuwen, M.; Vargas, A.; Vargyas, M.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vechernin, V.; Veldhoen, M.; Velure, A.; Venaruzzo, M.; Vercellin, E.; Vergara Limón, S.; Vernet, R.; Verweij, M.; Vickovic, L.; Viesti, G.; Viinikainen, J.; Vilakazi, Z.; Villalobos Baillie, O.; Vinogradov, A.; Vinogradov, L.; Vinogradov, Y.; Virgili, T.; Viyogi, Y. P.; Vodopyanov, A.; Völkl, M. A.; Voloshin, K.; Voloshin, S. A.; Volpe, G.; von Haller, B.; Vorobyev, I.; Vranic, D.; Vrláková, J.; Vulpescu, B.; Vyushin, A.; Wagner, B.; Wagner, J.; Wagner, V.; Wang, M.; Wang, Y.; Watanabe, D.; Weber, M.; Wessels, J. P.; Westerhoff, U.; Wiechula, J.; Wikne, J.; Wilde, M.; Wilk, G.; Wilkinson, J.; Williams, M. C. S.; Windelband, B.; Winn, M.; Xiang, C.; Yaldo, C. G.; Yamaguchi, Y.; Yang, H.; Yang, P.; Yang, S.; Yano, S.; Yasnopolskiy, S.; Yi, J.; Yin, Z.; Yoo, I.-K.; Yushmanov, I.; Zaccolo, V.; Zach, C.; Zaman, A.; Zampolli, C.; Zaporozhets, S.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zgura, I. S.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, F.; Zhou, Y.; Zhou, Zhuo; Zhu, H.; Zhu, J.; Zhu, X.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zinovjev, G.; Zoccarato, Y.; Zyzak, M.; Alice Collaboration

    2015-01-01

    The pT -differential production cross section of electrons from semileptonic decays of heavy-flavor hadrons has been measured at midrapidity in proton-proton collisions at √{s }=2.76 TeV in the transverse momentum range 0.5

  20. Searches for Natural Supersymmetry in Hadronic Final States with Heavy Flavor at ATLAS

    SciTech Connect

    Butler, Bart Clayton

    2012-12-01

    This thesis presents the hadronic-channel supersymmetric searches for direct sbottom and gluino-mediated sbottom and stop production performed on 4.71 fb-1 of √s = 7 TeV data collected by the ATLAS detector at the Large Hadron Collider. These signatures are characterized by final states with multiple b-tagged jets and missing transverse energy ( ET ) and the analysis strategy is chosen accordingly. Particular emphasis is placed on the utilization of the simplified models approach in signal characterization, optimization, and interpretation of results. No significant excess is observed resulting in limits set at 95% confidence level. Relative to the previous versions of the analyses, this iteration represents a several-fold increase in sensitivity to the new physics signatures considered. This is largely due to the use of three b-tag signal regions as well as signal regions based on initial state radiation.

  1. Bound Electron States in Skew-symmetric Quantum Wire Intersections

    DTIC Science & Technology

    2014-01-01

    in transistors, solar cells , LEDs, and diode lasers. They have also investigated quantum dots as agents for medical imaging and as possible qubits in... solar cells .” Chemical reviews 110.11 (2010): 6873-6890. [9] Bonadeo, Nicolas H., et al. ”Coherent optical control of the quantum state of a single...dots on GaAs /InP , (inset) a single InAs quantum dot. two reasons. First, the superposition of the ground and excited states de- phases more slowly in

  2. The low-lying electronic states of LiC

    NASA Technical Reports Server (NTRS)

    Ricca, Alessandra; Bauschlicher, Charles W., Jr.; Langhoff, Stephen R. (Technical Monitor)

    1995-01-01

    The spectroscopic constants for the doublet and quartet states of LiC below about 30,000/cm are determined using an internally contracted multireference configuration-interaction approach in conjunction with a [6s 5p 3d 2f] atomic natural orbital basis sets. All of the strongly bound states, X(sup 4)(SIGMA)(sup -),(1)(sup 2)(DELTA), (1)(sup 2)(SIGMA)(sup +), and (2)(sup 2) II, very ionic in character. The only bound-bound quartet transition in this energy range is (2)(sup 4)SIGMA(sup -) and Franck-Condon factors, Einstein A values, and lifetimes are reported for this transition.

  3. Magnetic Dipole Moment Measurements of Picosecond States in Even and Odd Heavy Nuclei

    NASA Astrophysics Data System (ADS)

    Ballon, Douglas Jude

    The perturbed angular correlation and 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 ('150)Sm traversing gadolinium targets, the temperature dependence of the transient hyperfine field is deduced at ('150)Sm nuclei traveling at 2 < v/v(,0) < 4. These are compared with similar measurements made using iron targets. Second, the deduced values of the g-factors of the 2(,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(,1)('-) and 5/2(,1)('-) states of ('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(,1)('+) states of neighboring even-even nuclei. The following is a list of g-factors that were measured during the course of this work: (UNFORMATTED TABLE FOLLOWS). g(('107)Ag, 3/2(,1)('-)) = 0.607 (119). g(('109)Ag, 3/2(,1)('-)) = 0.661 (105). g(('107)Ag, 5/2(,1)('-)) = 0.409 (66). g(('109)Ag, 5/2(,1)('-)) = 0.287 (57). g(('144)Nd, 2(,1)('+)) = 0.166 (41). g(('146)Nd, 2(,1)('+)) = 0.312 (49). g(('148)Nd, 2(,1)('+)) = 0.411 (42). g(('150)Nd,2(,1)('+)) = 0.418 (38). g(('148)Sm, 2(,1)('+)) = 0.301 (33). g(('150)Sm, 2(,1)('+)) = 0.381 (27). g(('152)Gd, 2(,1)('+)) = 0.444 (40). (TABLE ENDS). The results of the temperature dependence experiment show deviations from an earlier measurement made using thulium in iron. The g-factors measured in the lighter isotopes of neodymium and samarium are significantly below the collective Z/A value. Fair agreement with the data can be obtained if proton shell closure is assumed at Z = 64 for N < 88. The measured g-factors in the silver isotopes

  4. Quantitative Electron Probe Microanalysis: State of the Art

    NASA Technical Reports Server (NTRS)

    Carpernter, P. K.

    2005-01-01

    Quantitative electron-probe microanalysis (EPMA) has improved due to better instrument design and X-ray correction methods. Design improvement of the electron column and X-ray spectrometer has resulted in measurement precision that exceeds analytical accuracy. Wavelength-dispersive spectrometer (WDS) have layered-dispersive diffraction crystals with improved light-element sensitivity. Newer energy-dispersive spectrometers (EDS) have Si-drift detector elements, thin window designs, and digital processing electronics with X-ray throughput approaching that of WDS Systems. Using these systems, digital X-ray mapping coupled with spectrum imaging is a powerful compositional mapping tool. Improvements in analytical accuracy are due to better X-ray correction algorithms, mass absorption coefficient data sets,and analysis method for complex geometries. ZAF algorithms have ban superceded by Phi(pz) algorithms that better model the depth distribution of primary X-ray production. Complex thin film and particle geometries are treated using Phi(pz) algorithms, end results agree well with Monte Carlo simulations. For geological materials, X-ray absorption dominates the corretions end depends on the accuracy of mass absorption coefficient (MAC) data sets. However, few MACs have been experimentally measured, and the use of fitted coefficients continues due to general success of the analytical technique. A polynomial formulation of the Bence-Albec alpha-factor technique, calibrated using Phi(pz) algorithms, is used to critically evaluate accuracy issues and can be also be used for high 2% relative and is limited by measurement precision for ideal cases, but for many elements the analytical accuracy is unproven. The EPMA technique has improved to the point where it is frequently used instead of the petrogaphic microscope for reconnaissance work. Examples of stagnant research areas are: WDS detector design characterization of calibration standards, and the need for more complete

  5. Heavy-tailed phase-space distributions beyond Boltzmann-Gibbs: Confined laser-cooled atoms in a nonthermal state

    NASA Astrophysics Data System (ADS)

    Dechant, Andreas; Shafier, Shalom Tzvi; Kessler, David A.; Barkai, Eli

    2016-08-01

    The Boltzmann-Gibbs density, a central result of equilibrium statistical mechanics, relates the energy of a system in contact with a thermal bath to its equilibrium statistics. This relation is lost for nonthermal systems such as cold atoms in optical lattices, where the heat bath is replaced with the laser beams of the lattice. We investigate in detail the stationary phase-space probability for Sisyphus cooling under harmonic confinement. In particular, we elucidate whether the total energy of the system still describes its stationary state statistics. We find that this is true for the center part of the phase-space density for deep lattices, where the Boltzmann-Gibbs density provides an approximate description. The relation between energy and statistics also persists for strong confinement and in the limit of high energies, where the system becomes underdamped. However, the phase-space density now exhibits heavy power-law tails. In all three cases we find expressions for the leading-order phase-space density and corrections which break the equivalence of probability and energy and violate energy equipartition. The nonequilibrium nature of the steady state is corroborated by explicit violations of detailed balance. We complement these analytical results with numerical simulations to map out the intricate structure of the phase-space density.

  6. Heavy metal contamination characteristic of soil in WEEE (waste electrical and electronic equipment) dismantling community: a case study of Bangkok, Thailand.

    PubMed

    Damrongsiri, Seelawut; Vassanadumrongdee, Sujitra; Tanwattana, Puntita

    2016-09-01

    Sue Yai Utit is an old community located in Bangkok, Thailand which dismantles waste electrical and electronic equipment (WEEE). The surface soil samples at the dismantling site were contaminated with copper (Cu), lead (Pb), zinc (Zn), and nickel (Ni) higher than Dutch Standards, especially around the WEEE dumps. Residual fractions of Cu, Pb, Zn, and Ni in coarse soil particles were greater than in finer soil. However, those metals bonded to Fe-Mn oxides were considerably greater in fine soil particles. The distribution of Zn in the mobile fraction and a higher concentration in finer soil particles indicated its readily leachable character. The concentration of Cu, Pb, and Ni in both fine and coarse soil particles was mostly not significantly different. The fractionation of heavy metals at this dismantling site was comparable to the background. The contamination characteristics differed from pollution by other sources, which generally demonstrated the magnification of the non-residual fraction. A distribution pathway was proposed whereby contamination began by the deposition of WEEE scrap directly onto the soil surface as a source of heavy metal. This then accumulated, corroded, and was released via natural processes, becoming redistributed among the soil material. Therefore, the concentrations of both the residual and non-residual fractions of heavy metals in WEEE-contaminated soil increased.

  7. Thermal State of the Lithosphere During Late Heavy Bombardment: Implications for Early Life

    NASA Astrophysics Data System (ADS)

    Abramov, O.; Mojzsis, S. J.

    2008-12-01

    We model thermal effects of impacts on the terrestrial lithosphere during the period of Late Heavy Bombardment (LHB), a putative ~100 Ma epoch of sharply elevated impactor flux that reached a maximum at ca. 3.9 Ga. The goals of this work include estimating the degree to which the crust was molten or thermally metamorphosed during the LHB and evaluating habitability during this time period. We created a stochastic cratering model which populates all or part of the Earth's surface with craters within a probability field of constraints derived from the lunar cratering record, the size/frequency distribution of the asteroid belt, and dynamical models. For each crater in the model, a temperature field was calculated using analytical expressions for shock-deposited heat and central uplift. The resulting thermal anomaly was then introduced into a 3-dimensional model of the lithosphere, and allowed to cool by conduction in the subsurface and radiation/convection at the atmosphere interface. Parameters tested in the model include the duration, mass flux, and average impact velocity during the LHB, mean lithospheric thickness, lithospheric composition, and the presence or absence of oceans. We also assessed habitability by monitoring habitable volumes for mesophile (~20-50° C), thermophile (~50-80° C), and hyperthermophile (~80-110° C) microbial life in what we term the "geophysical habitable zone"; the volume of inhabited crust within ~4 km of the surface. Results of this work indicate that most of the crust was not melted or thermally metamorphosed to a significant degree under any reasonable scenario evaluated. Smaller impactors (1-10 km) were as important as gigantic basin formers (100+ km) in terms of sterilizing the habitable zone in the near-surface due to their far greater numbers (~170,000 impactors in the 1-10 km diameter range versus ~30 impactors in the 100+ km diameter range). However, large basin-forming craters are nonetheless more thermally and

  8. Combined study of the ground and unoccupied electronic states of graphite by electron energy-loss spectroscopy

    SciTech Connect

    Feng, Zhenbao; Löffler, Stefan; Eder, Franz; Meyer, Jannik C.; Su, Dangsheng; Schattschneider, Peter

    2013-11-14

    Both the unoccupied and ground electronic states of graphite have been studied by electron energy-loss spectroscopy in a transmission electron microscope. Electron energy-loss near-edge structures of the K-edge of carbon have been investigated in detail for scattering angles from 0 to 2.8 mrad. The π{sup *} and σ{sup *} components were separated. The angular and energy dependences of the π{sup *} and σ{sup *} structures were in fair agreement with theory. Electron energy loss Compton spectra of graphite were recorded at scattering angles from 45 to 68 mrad. One Compton scattering spectrum was obtained in 1 min compared with several hours or days using photons. The contributions of core electrons were calculated by the exact Hartree-Slater method in the Compton scattering region. The electron Compton profile for graphite is in good agreement with other conventional Compton profile measurements, as well as with theory, thus establishing the validity of the technique.

  9. Electronic Timekeeping: North Dakota State University Improves Payroll Processing.

    ERIC Educational Resources Information Center

    Vetter, Ronald J.; And Others

    1993-01-01

    North Dakota State University has adopted automated timekeeping to improve the efficiency and effectiveness of payroll processing. The microcomputer-based system accurately records and computes employee time, tracks labor distribution, accommodates complex labor policies and company pay practices, provides automatic data processing and reporting,…

  10. The Low-Lying Electronic States of Mg2(+)

    NASA Technical Reports Server (NTRS)

    Ricca, Alessandra; Bauschlicher, Charles W., Jr.

    1994-01-01

    The low-lying doublet and quartet states of Mg+ have been studied using a multireference configuration interaction approach. The effect of inner-shell correlation has been included using the core-polarization potential method. The computed spectroscopic constants, lifetimes, and oscillator strengths should help resolve the difference between the recent experiments and previous theoretical calculations.

  11. Study of the Electronic Surface State of III - V Compounds

    DTIC Science & Technology

    1976-03-15

    possible reason for the variation in Ep pinning observed by different groups , because EF is very sensitive to small (« 1 monolayer) of oxygen, and... foming a SchPtt.y barrier or by s^l amounts of oxygen. East,nan and cpworkers ba.e ^ alsp reported now finding n-type 3-S’s without surface state

  12. Characterizing the Locality of Diabatic States for Electronic Excitation Transfer by Decomposing the Diabatic Coupling

    SciTech Connect

    Vura-Weis, Josh; Newton, M. D.; Wasielewski, Michael R; Subotnik, J.E.

    2010-12-09

    A common strategy to calculate electronic coupling matrix elements for charge or energy transfer is to take the adiabatic states generated by electronic structure computations and rotate them to form localized diabatic states. In this paper, we show that, for intermolecular transfer of singlet electronic excitation, usually we cannot fully localize the electronic excitations in this way. Instead, we calculate putative initial and final states with small excitation tails caused by weak interactions with high energy excited states in the electronic manifold. These tails do not lead to substantial changes in the total diabatic coupling between states, but they do lead to a different partitioning of the total coupling between Coulomb (Förster), exchange (Dexter), and one-electron components. The tails may be reduced by using a multistate diabatic model or eliminated entirely by truncation (denoted as “chopping”). Without more information, we are unable to conclude with certainty whether the observed diabatic tails are a physical reality or a computational artifact. This research suggests that decomposition of the diabatic coupling between chromophores into Coulomb, exchange, and one-electron components may depend strongly on the number of states considered, and such results should be treated with caution.

  13. Ozone absorption spectroscopy in search of low-lying electronic states

    NASA Technical Reports Server (NTRS)

    Anderson, S. M.; Mauersberger, K.

    1995-01-01

    A spectrometer capable of detecting ozone absorption features 9 orders of magnitude weaker than the Hartley band has been employed to investigate the molecule's near-infrared absorption spectrum. At this sensitivity a wealth of information on the low-lying electronically excited states often believed to play a role in atmospheric chemistry is available in the form of vibrational and rotational structure. We have analyzed these spectra using a combination of digital filtering and isotope substitution and find evidence for three electronically excited states below 1.5 eV. The lowest of these states is metastable, bound by approximately 0.1 eV and probably the (3)A2 rather than the (3)B2 state. Its adiabatic electronic energy is 1.24 +/- 0.01 eV, slightly above the dissociation energy of the ground state. Two higher states, at 1.29 +/- 0.03 and 1.48 +/- 0.03 eV are identified as the (3)B2 and the (3)B1, respectively. Combined with other recent theoretical and experimental data on the low-lying electronic states of ozone, these results imply that these are, in fact, the lowest three excited states; that is, there are no electronically excited states of ozone lying below the energy of O(3P) + O2((3)Sigma(-), v = 0). Some of the implications for atmospheric chemistry are considered.

  14. Ground-state statistics of directed polymers with heavy-tailed disorder.

    PubMed

    Gueudre, Thomas; Le Doussal, Pierre; Bouchaud, Jean-Philippe; Rosso, Alberto

    2015-06-01

    In this mostly numerical study, we reconsider the statistical properties of the ground state of a directed polymer in a d=1+1 "hilly" disorder landscape, i.e., when the quenched disorder has power-law tails. When disorder is Gaussian, the polymer minimizes its total energy through a collective optimization, where the energy of each visited site only weakly contributes to the total. Conversely, a hilly landscape forces the polymer to distort and explore a larger portion of space to reach some particularly deep energy sites. As soon as the fifth moment of the disorder diverges, this mechanism radically changes the standard Kardar-Parisi-Zhang scaling behavior of the directed polymer, and new exponents prevail. After confirming again that the Flory argument accurately predicts these exponents in the tail-dominated phase, we investigate several other statistical features of the ground state that shed light on this unusual transition and on the accuracy of the Flory argument. We underline the theoretical challenge posed by this situation, which paradoxically becomes even more acute above the upper critical dimension.

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

    SciTech Connect

    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.

  16. Spectroscopic properties and potential energy curves of low-lying electronic states of RuC.

    PubMed

    Guo, Rui; Balasubramanian, K

    2004-04-22

    The RuC molecule has been a challenging species due to the open-shell nature of Ru resulting in a large number of low-lying electronic states. We have carried out state-of-the-art calculations using the complete active space multiconfiguration self-consistent field followed by multireference configuration interaction methods that included up to 18 million configurations, in conjunction with relativistic effects. We have computed 29 low-lying electronic states of RuC with different spin multiplicities and spatial symmetries with energy separations less than 38,000 cm(-1). We find two very closely low-lying electronic states for RuC, viz., 1Sigma+ and 3Delta with the 1Sigma+ being stabilized at higher levels of theory. Our computed spectroscopic constants and dipole moments are in good agreement with experiment although we have reported more electronic states than those that have been observed experimentally. Our computations reveal a strongly bound 1Sigma+ state with a large dipole moment which is most likely the experimentally observed ground state and an energetically close 3Delta state with a smaller dipole moment. Overall our computed spectroscopic constants of the excited states with energy separations less than 18,000 cm(-1) agree quite well with those of the corresponding observed states.

  17. High intensity production of high and medium charge state uraniumand other heavy ion beams with VENUS

    SciTech Connect

    Leitner, Daniela; Galloway, Michelle L.; Loew, Timothy J.; Lyneis, Claude M.; Rodriguez, Ingrid Castro; Todd, Damon S.

    2007-11-15

    The next generation, superconducting ECR ion source VENUS(Versatile ECR ion source for NUclear Science) started operation with 28GHzmicrowave heating in 2004. Since then it has produced world recordion beam intensities. For example, 2850 e mu A of O6+, 200 e mu A of U33+or U34+, and in respect to high charge state ions, 1 e mu A of Ar18+, 270e mu A of Ar16+, 28 e mu A of Xe35+ and 4.9 e mu A of U47+ have beenproduced. A brief overview of the latest developments leading to theserecord intensities is given and the production of high intensity uraniumbeams is discussed in more detail.

  18. Modified Ion-Acoustic Shock Waves and Double Layers in a Degenerate Electron-Positron-Ion Plasma in Presence of Heavy Negative Ions

    NASA Astrophysics Data System (ADS)

    Hossen, M. A.; Hossen, M. R.; Mamun, A. A.

    2014-12-01

    A general theory for nonlinear propagation of one dimensional modified ion-acoustic waves in an unmagnetized electron-positron-ion (e-p-i) degenerate plasma is investigated. This plasma system is assumed to contain relativistic electron and positron fluids, non-degenerate viscous positive ions, and negatively charged static heavy ions. The modified Burgers and Gardner equations have been derived by employing the reductive perturbation method and analyzed in order to identify the basic features (polarity, width, speed, etc.) of shock and double layer (DL) structures. It is observed that the basic features of these shock and DL structures obtained from this analysis are significantly different from those obtained from the analysis of standard Gardner or Burgers equations. The implications of these results in space and interstellar compact objects (viz. non-rotating white dwarfs, neutron stars, etc.) are also briefly mentioned.

  19. Electron Impact Excitation of Xenon from the Ground State and the Metastable State to the 5p57p Levels

    NASA Astrophysics Data System (ADS)

    Chen, Zhan-Bin; Dong, Chen-Zhong; Xie, Lu-You; Jiang, Jun

    2014-03-01

    Electron impact excitation cross sections from the ground state and the lowest metastable state 5p56s J = 2 to the excited states of the 5p57p configuration of xenon are calculated systematically using the fully relativistic distorted wave method. Special attention is paid to the configuration interaction effects in the wave-function expansion of target states. The results are in good agreement with the recent experimental data by Jung et al. [Phys. Rev. A 80 (2009) 062708] over the measured energy range. These accurate theoretical results can be used in the modeling and diagnosis of plasmas containing xenon.

  20. 78 FR 49510 - Cross-Media Electronic Reporting: Authorized Program Revision Approval, State of Montana

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-14

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY Cross-Media Electronic Reporting: Authorized Program Revision Approval, State of Montana AGENCY... INFORMATION: On October 13, 2005, the final Cross-Media Electronic Reporting Rule (CROMERR) was published...