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Sample records for e1-transitions

  1. Octupole deformation in sup 221 Fr; E1 transition rates

    SciTech Connect

    Liang, C.F.; Peghaire, A. ); Sheline, R.K. )

    1990-07-10

    Experimental data following the alpha decay of{sup 225}Ac are interpreted in terms of a spectroscopy in {sup 221}Fr consistent with octupole deformation. However, the measured E1 transition probabilities suggest that the low lying bands in {sup 221}Fr are considerably more mixed than in nuclei with slightly higher mass number. It is suggested that this mixing of states in {sup 221}Fr is indicative of the partial collapse of Nilsson-like orbitals into more degenerate shell model orbitals.

  2. Enhanced E1 transitions and {alpha}-clustering in {sup 212}Po

    SciTech Connect

    Suzuki, Y.; Ohkubo, S.

    2011-05-06

    An {alpha}+{sup 208}Pb(0{sup +},3{sup -}) cluster model explains the recently observed enhanced E1 transitions from the new negative-parity levels to the yrast states in {sup 212}Po. Heavy and light nuclei present good examples of surface clustering and well-localized clustering.

  3. Enhanced E1 transitions and {alpha}+{sup 208}Pb(3{sup -}) clustering in {sup 212}Po

    SciTech Connect

    Suzuki, Y.; Ohkubo, S.

    2010-10-15

    We formulate a model for {sup 212}Po, based on the coupled-channels of {alpha}+{sup 208}Pb(0{sup +}) and {alpha}+{sup 208}Pb(3{sup -}) in which the {alpha}-Pb interaction contains scalar, quadrupole, and octupole terms. The model reproduces the recently observed enhanced E1 transitions from the several new negative-parity levels to the yrast states. Because these data are hard to understand in the shell model, this success gives a strong support for a unique role of {alpha}+{sup 208}Pb(3{sup -}) clustering in {sup 212}Po.

  4. Weak- and hyperfine-interaction-induced 1s2s 1S0 → 1s2 1S0 E1 transition rates of He-like ions

    NASA Astrophysics Data System (ADS)

    Laima, Radžiūtė; Erikas, Gaidamauskas; Gediminas, Gaigalas; Li, Ji-Guang; Dong, Chen-Zhong; Jönsson, Per

    2015-04-01

    Weak- and hyperfine-interaction-induced 1s2s 1S0 → 1s2 1S0 E1 transition rates for the isoelectronic sequence of He-like ions have been calculated using the multi-configuration Dirac-Hartree-Fock (MCDHF) and relativistic configuration interaction methods. The results should be helpful for the future experimental investigations of parity non-conservation effects. Project supported by the National Natural Science Foundation of China (Grant Nos. 11274254, 11147108, 10979007, U1331122, and U1332206) and in part by the National Basic Research Program of China (Grant No. 2013CB922200).

  5. Multi-configuration Dirac-Hartree-Fock calculations of the transition rates of 2s22p2 - 2s2p3 and 2s2p3 - 2s22pnl (n ≥ 3) E1 transitions of N+

    NASA Astrophysics Data System (ADS)

    Shen, Xiaozhi; Liu, Juan; Zhou, Fuyang

    2016-10-01

    Wavefunctions were determined using the multi-configuration Dirac-Hartree-Fock method. The core-core, core-valence, valence correlation, Breit interaction and quantum electrodynamics effects, as well as some higher-order correlation effects, were considered to obtain accurate wavelengths (λ), oscillator strengths (gf) and transition rates (A) of 2s22p2 - 2s2p3, 2s2p3 - 2s22pnl (n ≥ 3) and 2s2p3 - 2s2p23s E1 transitions. The branching ratio of 2s2p3 5S^o_2 (namely Aλ2143.45/Aλ2139.68) based on the latest calculation of 2.462 ± 0.119 is recommended for the determination of a nebula's electron temperature and electron density. The largest calculated gf value of 2s2p3 - 2s22p4p is λ630.65, differing from that of λ1060.2 (i.e. 2s2p3 3P^o_2 - 2s22p4p 3S1) that was observed with the largest intensities in the Orion Nebula spectrum. In addition, the energy levels and the splittings of 2s2p3, the extremely difficult calculations of the rates of two-electron one-photon transitions as well as those of the very small intercombination A of 2s2p3 5S^o_2 were studied in detail. Because of the weak spin-orbit interaction, accurately calculating the levels 3P^o_{1,2,0} (or 3D^o_{3,2,1}) and their transition matrix elements is very sensitive to relativistic and electron correlation effects. A special case for this is when the transition operators synchronously applied to wavefunctions with regard to 2s2p3 3Po and 2s22pnl (n = 4) become extremely sensitive to some higher-order correlation effects.

  6. Calculation of energy levels, {ital E}1 transition amplitudes, and parity violation in francium

    SciTech Connect

    Dzuba, V.A.; Flambaum, V.V.; Sushkov, O.P.

    1995-05-01

    Many-body perturbation theory in the screened Coulomb interaction was used to calculate energy levels, {ital E}1 trransition amplitudes, and the parity-nonconserving (PNC) {ital E}1 amplitude of the 7{ital s}-8{ital s} transition in francium. The method takes into account the core-polarization effect, the second-order correlations, and the three dominating sequences of higher-order correlation diagrams: screening of the electron-electron interaction, particle-hole interaction, and the iterations of the self-energy operator. The result for the PNC amplitude for {sup 223}Fr is {ital E}1(7{ital s}-8{ital s})=(1.59{plus_minus}{similar_to}1%){times}10{sup {minus}10}{ital iea}{sub {ital B}}({minus}{ital Q}{sub {ital W}}/{ital N}), where {ital Q}{sub {ital W}} is the weak charge of the nucleus, {ital N}=136 is the number of neutrons, {ital e}={vert_bar}{ital e}{vert_bar} is the elementary charge, and {ital a}{sub {ital B}} is the Bohr radius. Our prediction for the position of the 8{ital s} energy level of Fr, which has not been measured yet, is 13 110 cm{sup {minus}1} below the limit of the continuous spectrum. The accuracy of the calculations was controlled by comparison with available experimental data and analogous calculations for cesium. It is estimated to be {similar_to}0.1% for the energy levels and {similar_to}1% for the transition amplitudes.

  7. On the enhanced E1 transitions in the K = 3/2 parity doublet band in 223Ra

    NASA Astrophysics Data System (ADS)

    Mach, H.; Lindroth, A.; Ruchowska, E.; Kvasil, J.; Fogelberg, B.; Gulda, K.; Aas, A. J.; Borge, M. J. G.; Grant, I. S.; Hagebø, E.; Kurcewicz, W.; Martinez, T.; Rubio, B.; Smith, J. F.; Steffensen, K.; Tain, J. L.; Tengblad, O.; Thorsteinsen, T. F.

    2016-06-01

    We have applied the fast timing βγγ (t) technique to remeasure lifetimes of selected states in 223Ra populated in the β- decay of 223Fr. T_{1/2}=587(12) ps and 210(13)ps have been obtained for the 3/2- and 5/2- states at 50.1 and 79.7 keV, that are more accurate than the previous values of 630(70)ps and 166(55)ps, respectively. Our \\vert D0\\vert value of 0.155(10)e·fm obtained for the K=3/2 configuration together with the available values of \\vert D0\\vert for the K=1/2 and K=5/2 parity doublet bands establish the configuration dependence of \\vert D0\\vert at low spins in this nucleus. Results of theoretical calculations performed for 223Ra, using the quasiparticle-phonon model (QPM) with inclusion of the Coriolis coupling, reasonably well reproduce octupole correlations in this nucleus.

  8. Fast electric dipole transitions in Ra-Ac nuclei

    SciTech Connect

    Ahmad, I.

    1985-01-01

    Lifetime of levels in /sup 225/Ra, /sup 225/Ac, and /sup 227/Ac have been measured by delayed coincidence techniques and these have been used to determine the E1 gamma-ray transition probabilities. The reduced E1 transition probabilities. The reduced E1 transition probabilities in /sup 225/Ra and /sup 225/Ac are about two orders of magnitude larger than the values in mid-actinide nuclei. On the other hand, the E1 rate in /sup 227/Ac is similar to those measured in heavier actinides. Previous studies suggest the presence of octupole deformation in all the three nuclei. The present investigation indicates that fast E1 transitions occur for nuclei with octupole deformation. However, the studies also show that there is no one-to-one correspondence between E1 rate and octupole deformation. 13 refs., 4 figs.

  9. Octupole correlation effects in nuclei

    SciTech Connect

    Chasman, R.R.

    1992-01-01

    Octupole correlation effects in nuclei are discussed from the point of view of many-body wavefunctions as well as mean-field methods. The light actinides, where octupole effects are largest, are considered in detail. Comparisons of theory and experiment are made for energy splittings of parity doublets; E1 transition matrix elements and one-nucleon transfer reactions.

  10. Octupole correlation effects in nuclei

    SciTech Connect

    Chasman, R.R.

    1992-08-01

    Octupole correlation effects in nuclei are discussed from the point of view of many-body wavefunctions as well as mean-field methods. The light actinides, where octupole effects are largest, are considered in detail. Comparisons of theory and experiment are made for energy splittings of parity doublets; E1 transition matrix elements and one-nucleon transfer reactions.

  11. ACCURATE ESTIMATIONS OF STELLAR AND INTERSTELLAR TRANSITION LINES OF TRIPLY IONIZED GERMANIUM

    SciTech Connect

    Dutta, Narendra Nath; Majumder, Sonjoy E-mail: sonjoy@gmail.com

    2011-08-10

    In this paper, we report on weighted oscillator strengths of E1 transitions and transition probabilities of E2 transitions among different low-lying states of triply ionized germanium using highly correlated relativistic coupled cluster (RCC) method. Due to the abundance of Ge IV in the solar system, planetary nebulae, white dwarf stars, etc., the study of such transitions is important from an astrophysical point of view. The weighted oscillator strengths of E1 transitions are presented in length and velocity gauge forms to check the accuracy of the calculations. We find excellent agreement between calculated and experimental excitation energies. Oscillator strengths of few transitions, wherever studied in the literature via other theoretical and experimental approaches, are compared with our RCC calculations.

  12. Phenomenological description of rotational bands in the pear shaped nuclei

    SciTech Connect

    Raduta, A.A.; Raduta, A.H.; Faessler, A.

    1997-04-01

    The coherent state model is extended to negative parity states. Thus three positive (ground, beta, and gamma) and three negative parity bands are projected out from three orthogonal states exhibiting both quadrupole and octupole deformations. An effective Hamiltonian acting on the space of projected states is constructed. For illustration, the numerical application is confined to the ground and K{sup {pi}}=0{sup {minus}} bands. In a certain range of deformations these bands show a {open_quotes}shell{close_quotes} structure. Good agreement with experimental data in {sup 218,220,226}Ra is obtained for energy levels and E1 transition probabilities. Specific features like the interleaved structure, the low energy of the state 1{sup {minus}}, and strong E1 transitions are well described. {copyright} {ital 1997} {ital The American Physical Society}

  13. Reflection Asymmetric Shapes in the Neutron-Rich 140,143Ba Isotopes

    NASA Astrophysics Data System (ADS)

    Zhu Sheng-jiang (S, J. Zhu; Wang, Mu-ge; J, H. Hamilton; A, V. Ramayya; B, R. S. Babu; W, C. Ma; Long, Gui-lu; Deng, Jing-kang; Zhu, Ling-yan; Li, Ming; T, N. Ginter; J, Komicki; J, D. Cole; R, Aryaeinejad; Y, K. Dardenne; M, W. Drigert; J, O. Rasmussen; Ts, Yu Oganessian; M, A. Stoyer; S, Y. Chu; K, E. Gregorich; M, F. Mohar; S, G. Prussin; I, Y. Lee; N, R. Johnson; F, K. McGowan

    1997-08-01

    Level schemes for the neutron-rich 140,143Ba nuclei have been determined by study of prompt γ-rays in spontaneous fission of 252Cf. The level pattern and enhanced E1 transitions between π = + and π = - bands show reflection asymmetric shapes with simplex quantum number s = +1 in 140Ba and s = ±i in 143Ba, respectively. The octupole deformation stability with spin variation has been discussed.

  14. Alternating parity structure in doubly odd /sup 218/Ac

    SciTech Connect

    Debray, M.E.; Davidson, M.; Kreiner, A.J.; Davidson, J.; Falcone, G.; Hojman, D.; Santos, D.

    1989-03-01

    States in doubly odd /sup 218/Ac have been studied using in-beam ..cap alpha..-, ..gamma..-, and e/sup -/-spectroscopy techniques mainly through the /sup 209/Bi(/sup 12/C,3n)= fusion-evaporation reaction. /sup 218/Ac shows a band structure, with interleaved states of alternating parities connected by enhanced B(E1) transitions, which is strikingly similar to the one in its isotone /sup 217/Ra.

  15. Recent results at the N = Z line with GASP and EUROBALL

    SciTech Connect

    Farnea, E.

    2004-02-27

    Valuable information on the validity of the isospin symmetry was obtained by studying nuclei close to the N = Z line with the GASP and EUROBALL {gamma}-ray spectrometres coupled to ancillary devices. Here a few selected results on the study of mirror nuclei are presented, together with an estimate of the isospin mixing probability through the measurement of a forbidden E1 transition in 64Ge.

  16. Relativistic Many-body Moller-Plesset Perturbation Theory Calculations of the Energy Levels and Transition Probabilities in Na- to P-like Xe Ions

    SciTech Connect

    Vilkas, M J; Ishikawa, Y; Trabert, E

    2007-03-27

    Relativistic multireference many-body perturbation theory calculations have been performed on Xe{sup 43+}-Xe{sup 39+} ions, resulting in energy levels, electric dipole transition probabilities, and level lifetimes. The second-order many-body perturbation theory calculation of energy levels included mass shifts, frequency-dependent Breit correction and Lamb shifts. The calculated transition energies and E1 transition rates are used to present synthetic spectra in the extreme ultraviolet range for some of the Xe ions.

  17. Inter-band coincidences in the superdeformed well of {sup 190}Hg from gammasphere

    SciTech Connect

    Crowell, B.; Carpenter, M.P.; Janssens, R.V.F.

    1995-08-01

    Very few experimental observables are ordinarily accessible for superdeformed (SD) states in the A {approximately} 150 and A {approximately} 190 regions. The gamma-decay out of the superdeformed bands usually proceeds directly to the normally deformed states, through highly fragmented pathways, making it difficult to determine the spins, parities and excitation energies of the SD states. The in-band E2 transitions are so collective (2 x 10{sup 3} single-particle units in the A {approximately} 190 region) that it is typically impossible to detect any of the competing M1 and E1 transitions between states in the SD well.

  18. Radiative p 15N Capture in the Region of Astrophysical Energies

    NASA Astrophysics Data System (ADS)

    Dubovichenko, S. B.; Burtebaev, N.; Dzhazairov-Kakhramanov, A. V.; Alimov, D. K.

    2016-06-01

    Within the framework of the modified potential cluster model with classification of orbital states according to the Young schemes, the possibility of describing experimental data for the astrophysical S-factor of p 15N radiative capture at energies from 50 to 1500 keV is considered. It is shown that on the basis of M1 and E1 transitions from various p 15N scattering states to the ground state of the 16O nucleus in the p 15N channel it is entirely possible to successfully explain the overall behavior of the S-factor in the considered energy region in the presence of two resonances.

  19. Measurement method for the nuclear anapole moment of laser-trapped alkali-metal atoms

    SciTech Connect

    Gomez, E.; Aubin, S.; Sprouse, G. D.; Orozco, L. A.; DeMille, D. P.

    2007-03-15

    Weak interactions within a nucleus generate a nuclear spin dependent, parity-violating electromagnetic moment, the anapole moment. We analyze a method to measure the nuclear anapole moment through the electric dipole transition it induces between hyperfine states of the ground level. The method requires tight confinement of the atoms to position them at the antinode of a standing wave Fabry-Perot cavity driving the anapole-induced microwave E1 transition. We explore the necessary limits in the number of atoms, excitation fields, trap type, interrogation method, and systematic tests necessary for such measurements in francium, the heaviest alkali.

  20. Evidence for the onset of reflection asymmetry in sup 216 Fr

    SciTech Connect

    Debray, M.E.; Davidson, J.; Davidson, M.; Kreiner, A.J.; Hojman, D.; Santos, D. ); Ahn, K.; Fossan, D.B.; Liang, Y.; Ma, R.; Paul, E.S.; Piel, W.F. Jr.; Xu, N. )

    1990-05-01

    States in doubly odd {sup 216}Fr have been studied using in-beam {alpha}, {gamma}, and {ital e}{sup {minus}} spectroscopy techniques through the {sup 208}Pb({sup 11}B3{ital n}) fusion-evaporation reaction. {sup 216}Fr shows a band structure with interleaved states of alternating parities connected by enhanced {ital B}({ital E}1) transitions. It represents the lowest-mass corner of the region ({ital Z}{ge}87,{ital N}{ge}129) in which this phenomenon is observed.

  1. Octupole shapes in heavy nuclei

    SciTech Connect

    Ahmad, I.

    1994-08-01

    Theoretical calculations and measurements show the presence of strong octupole correlations in thecyround states and low-lying states of odd-mass and odd-odd nuclei in the RaPa region. Evidence for octupole correlations is provided by the observation of parity doublets and reductions in M1 matrix elements, decoupling parameters, and Coriolis matrix elements Involving high-j states. Enhancement of E1 transition rates has also been observed for some of the octupole deformed nuclei. The most convincing argument for octupole deformation is provided by the similarities of the reduced alpha decay rates to the two members of parity doublets.

  2. Octupole Deformation Bands of πh11/2 in Neutron-Rich 145,147La Nuclei

    NASA Astrophysics Data System (ADS)

    Zhu, Sheng-jiang; S, Zhu J.; Wang, Mu-ge; J, Hamilton H.; A, Ramayya V.; B, Babu R. S.; W, Ma C.; Long, Gui-lu; Zhu, Ling-yan; Li, Ming; A, Sakhaee; Gan, Cui-yun; Yang, Li-ming; J, Komicki; J, Cole D.; R, Aryaeinejad; M, Drigert W.; J, Rasmussen O.; M, Stoyer A.; S, Chu Y.; K, Gregorich E.; M, Mohar F.; S, Prussin G.; I, Lee Y.; Yu, Oganessian Ts; G, Ter-Akopian M.; A, Daniel V.

    1999-03-01

    Octupole deformation bands built on πh11/2 orbital in neutron-rich odd-Z 145,147La nuclei have been investigated by measuring the prompt γ-rays emitted from the 252Cf source. The alternating parity band structures and strong E1 transitions observed between negative- and positive-parity bands in both nuclei indicate the octupole deformation enhanced by the h11/2 single proton coupling. According to observed energy displacements the octupole deformation becomes stable at the intermediate spin states.

  3. New decay pattern of negative-parity states at N=90

    NASA Astrophysics Data System (ADS)

    Chakraborty, A.; Prados-Estévez, F. M.; Choudry, S. N.; Crider, B. P.; Garrett, P. E.; Kulp, W. D.; Kumar, A.; McEllistrem, M. T.; Mukhopadhyay, S.; Mynk, M. G.; Orce, J. N.; Peters, E. E.; Wood, J. L.; Yates, S. W.

    2012-12-01

    Excited states in 150Nd have been investigated with the 150Nd(n,n'γ) reaction. In addition to the previously known Kπ = 0- band, a new Kπ = 2- band is established, and level lifetimes are determined for all the reported band members. These lifetime data reveal a pattern of enhanced E1 transition strengths, similar to that observed in 152Sm and unprecedented in other nuclei, thus suggesting a systematic pattern for octupole collectivity in the N = 90 isotones. The pattern lies outside of the various model descriptions that have been put forward for nuclei in this or any other region.

  4. Energies and Electric Dipole Transitions for Low-Lying Levels of Protactinium IV and Uranium V

    NASA Astrophysics Data System (ADS)

    Ürer, Güldem; Özdemir, Leyla

    2012-02-01

    We have reported a relativistic multiconfiguration Dirac-Fock (MCDF) study on low-lying level structures of protactinium IV (Z =91) and uranium V (Z =92) ions. Excitation energies and electric dipole (E1) transition parameters (wavelengths, oscillator strengths, and transition rates) for these low-lying levels have been given. We have also investigated the influence of the transverse Breit and quantum electrodynamic (QED) contributions besides correlation effects on the level structure. A comparison has been made with a few available data for these ions in the literature.

  5. Fe K-edge X-ray resonant magnetic scattering from Ba(Fe1−xCox)2As2 superconductors

    SciTech Connect

    Kim, Min Gyu; Kreyssig, Andreas; Lee, Yongbin; McQueeney, Robert J.; Harmon, Bruce N.; Goldman, Alan I.

    2012-06-15

    We present an X-ray resonant magnetic scattering study at the Fe-K absorption edge of the BaFe2As2 compound. The energy spectrum of the resonant scattering, together with our calculation using the full-potential linear-augmented plane wave method with a local density functional suggests that the observed resonant scattering arises from electric dipole (E1) transitions. We discuss the role of Fe K-edge X-ray resonant magnetic scattering in understanding the relationship between the structure and the antiferromagnetic transition in the doped Ba(Fe1−xCox)2As2 superconductors.

  6. Electron-Hole Transitions in Multiply Charged Ions for Precision Laser Spectroscopy and Searching for Variations in {alpha}

    SciTech Connect

    Berengut, J. C.; Dzuba, V. A.; Flambaum, V. V.; Ong, A.

    2011-05-27

    We consider transitions of electron holes (vacancies in otherwise filled shells of atomic systems) in multiply charged ions that, due to level crossing of the holes, have frequencies within the range of optical atomic clocks. Strong E1 transitions provide options for laser cooling and trapping, while narrow transitions can be used for high-precision spectroscopy and tests of fundamental physics. We show that hole transitions can have extremely high sensitivity to {alpha} variation and propose candidate transitions that have much larger {alpha} sensitivities than any previously seen in atomic systems.

  7. Evidence for reflection asymmetric shape in the nucleus sup 151 sub 61 Pm sub 90

    SciTech Connect

    Sood, P.C.; Sheline, R.K. )

    1989-09-01

    The occurrence of multiple parity doublets, enhanced {ital E}1 transitions between parity-doublet levels, characteristic decoupling parameters for {ital K}=1/2 parity-doublet bands, and hybridization of the nuclear magnetic moments are sought as evidence for reflection asymmetric shape in odd-{ital Z} odd-mass rare-earth nuclei. Specific results consistent with such an assumption are presented for the nucleus {sup 151}{sub 61}Pm{sub 90}. Suggestions are offered for further experiments following a review of available information on other nuclei of the region.

  8. A Large-scale Relativistic Configuration-interaction Approach: Application to the 4s2 - 4s4p Transition Energies and E1 Rates for Zn-like Ions

    SciTech Connect

    Chen, M H; Cheng, K T

    2009-08-28

    Relativistic configuration-interaction calculations of the 4s4p excitation energies and 4s{sup 2} - 4s4p E1 transitions for Zn-like ions from Z = 30 to 92 are shown. B-spline basis functions are used for these large-scale calculations. QED corrections to the excitation energies are also calculated. Results are in good agreement with other theories and with experiment, and demonstrate the utility of this method for high-precision atomic structure calculations not just for few-electron systems but also for large atomic systems such as Zn-like ions along the entire isoelectronic sequence.

  9. New results on the superdeformed {sup 196}Pb nucleus: The decay of the excited bands to the yrast band

    SciTech Connect

    Bouneau, S.; Azaiez, F.; Duprat, J.

    1996-12-31

    The study of the superdeformed (SD) {sup 196}Pb nucleus has been revisited using the EUROGAM phase 2 spectrometer. In addition to the known yrast and two lowest excited SD bands, a third excited SD band has been seen. All of the three excited bands were found to decay to the yrast SD band through, presumably, E1 transitions, allowing relative spin and excitation energy assignments. Comparisons with calculations using the random-phase approximation suggest that all three excited bands can be interpreted as octupole vibrational structures.

  10. Theoretical study of the α +d →6Li +γ astrophysical capture process in a three-body model

    NASA Astrophysics Data System (ADS)

    Tursunov, E. M.; Kadyrov, A. S.; Turakulov, S. A.; Bray, I.

    2016-07-01

    The astrophysical capture process α +d →6Li is studied in a three-body model. The initial state is factorized into the deuteron bound state and the (α +d )-scattering state. The final nucleus 6Li (1+) is described as a three-body bound state α +n +p in the hyperspherical Lagrange-mesh method. The contribution of the E 1 -transition operator from the initial isosinglet states to the isotriplet components of the final state is estimated to be negligible. An estimation of the forbidden E 1 transition to the isosinglet components of the final state is comparable with the corresponding results of the two-body model. However, the contribution of the E 2 -transition operator is found to be much smaller than the corresponding estimations of the two-body model. The three-body model perfectly matches the new experimental data of the LUNA Collaboration with the spectroscopic factor of 2.586 estimated from the bound-state wave functions of 6Li and a deuteron.

  11. Direct Neutron Capture Calculations with Covariant Density Functional Theory Inputs

    NASA Astrophysics Data System (ADS)

    Zhang, Shi-Sheng; Peng, Jin-Peng; Smith, Michael S.; Arbanas, Goran; Kozub, Ray L.

    2014-09-01

    Predictions of direct neutron capture are of vital importance for simulations of nucleosynthesis in supernovae, merging neutron stars, and other astrophysical environments. We calculate the direct capture cross sections for E1 transitions using nuclear structure information from a covariant density functional theory as input for the FRESCO coupled-channels reaction code. We find good agreement of our predictions with experimental cross section data on the double closed-shell targets 16O, 48Ca, and 90Zr, and the exotic nucleus 36S. Extensions of the technique for unstable nuclei and for large-scale calculations will be discussed. Predictions of direct neutron capture are of vital importance for simulations of nucleosynthesis in supernovae, merging neutron stars, and other astrophysical environments. We calculate the direct capture cross sections for E1 transitions using nuclear structure information from a covariant density functional theory as input for the FRESCO coupled-channels reaction code. We find good agreement of our predictions with experimental cross section data on the double closed-shell targets 16O, 48Ca, and 90Zr, and the exotic nucleus 36S. Extensions of the technique for unstable nuclei and for large-scale calculations will be discussed. Supported by the U.S. Dept. of Energy, Office of Nuclear Physics.

  12. Coarse-grained simulations of transitions in the E2-to-E1 conformations for Ca ATPase (SERCA) show entropy-enthalpy compensation.

    PubMed

    Nagarajan, Anu; Andersen, Jens Peter; Woolf, Thomas B

    2012-09-28

    SERCA is a membrane transport protein that has been extensively studied. There are a large number of highly resolved X-ray structures and several hundred mutations that have been characterized functionally. Despite this, the molecular details of the catalytic cycle, a cycle that includes large conformational changes, is not fully understood. In this computational study, we provide molecular dynamics descriptions of conformational changes during the E2→E1 transitions. The motivating point for these calculations was a series of insertion mutants in the A-M3 linker region that led to significant shifts in measured rates between the E2 and E1 states, as shown by experimental characterization. Using coarse-grained dynamic importance sampling within the context of a population shift framework, we sample on the intermediates along the transition pathway to address the mechanism for the conformational changes and the effects of the insertion mutations on the kinetics of the transition. The calculations define an approximation for the relative changes in entropy and enthalpy along the transition. These are found to be important for understanding the experimentally observed differences in rates. In particular, the interactions between cytoplasmic domains, water interactions, and the shifts in protein degrees of freedom with the insertion mutations show mutual compensation for the E2→E1 transitions in wild-type and mutant systems.

  13. Discovery of a 10 {mu}s isomeric state in {sub 63}{sup 139}Eu

    SciTech Connect

    Cullen, D. M.; Mason, P. J. R; Kishada, A. M.; Procter, M. G.; Rigby, S. V.; Varley, B. J.; Scholey, C.; Eeckhaudt, S.; Grahn, T.; Greenlees, P. T.; Jakobsson, U.; Jones, P. M.; Julin, R.; Juutinen, S.; Ketelhut, S.; Leino, M.; Leppaenen, A.-P.; Maentyniemi, K.; Nieminen, P.; Nyman, M.

    2011-01-15

    Recoil-isomer tagging with the {sup 54}Fe+{sup 92}Mo reaction was used to establish a 10(2)-{mu}s isomeric state in {sup 139}Eu. Prompt versus delayed {gamma}-ray coincidence data have revealed the presence of a prompt rotational band built upon the isomer. The alignment properties of the states in this band show that the isomer is based upon a proton g{sub 7/2} configuration. The decay of the isomer takes place through a single 26-keV E1 transition. The {gamma}-ray transition strength for this decay is consistent with those established in the neighboring isomeric gamma-soft nuclei. In these nuclei, isomers are expected to form as a consequence of differences in nuclear shapes or configurations, and the natural hindrance associated with configuration-changing E1 transitions. The isomeric nature of the state in {sup 139}Eu is reasoned to be because of difference in shape of the proton g{sub 7/2} state and the proton h{sub 11/2} ground state to which it decays.

  14. Astrophysical S factors for radiative proton capture by {sup 3}H and {sup 7}Li nuclei

    SciTech Connect

    Dubovichenko, S. B.

    2011-03-15

    Within the potential cluster model where orbital states are classified according to Young diagrams and isospin, astrophysical S factors are considered for radiative proton capture by {sup 3}H and {sup 7}Li nuclei at energies of up to 1 and 10 keV, respectively. It is shown that the approach used, which takes into account only the E1 transition for the p{sup 3}H capture process, makes it possible to describe well the most recent experimental data at c.m. energies in the range from 50 keV to 5MeV. In the case of proton capture by {sup 7}Li nuclei, an M1 processwas taken into account in addition to the E1 transition, and a general behavior and the magnitude of the experimental S factor could be correctly reproduced owing to this at astrophysical energies, including the region around the resonance at 0.441 MeV (in the laboratory frame).

  15. Optical properties of GaSb measured using photoluminescence and photoreflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Jo, Hyun-Jun; So, Mo Geun; Kim, Jong Su; Lee, Sang Jun

    2016-09-01

    The optical properties of a GaSb layer were investigated using temperature-dependent photoluminescence (PL) and photoreflectance (PR) measurements. The defect-related transitions were observed at 0.714 and 0.728 eV in the PL measurements at 10 K. The band-to-band transition was observed at 0.712 eV in the PL measurement at 300 K. With decreasing temperature, the behavior of the defect-related transition changed slowly compared to the band-to-band transition. The PR spectrum at 300 K showed four signals of E 0 (0.72 eV), E 0 + Δ0 (1.52 eV), E 1 (2.07 eV) and E 1 + Δ1 (2.53 eV). The behavior of the E 1 transition was similar to that of the E 0 transition because the two transitions are band-to-band transitions. The behaviors of the eh transitions from the PL spectra were similar to the results for the E 0 of the PR spectra. The two PR signals of the E 1 transitions using below and above pumping were in good agreement across all temperatures. We confirmed that the below pumping technique was useful in the PR measurement.

  16. An experimental limit on parity mixing in atomic hydrogen

    SciTech Connect

    Fehrenbach, C.C.W.

    1993-12-31

    An experiment was performed to detect the forbidden E1 transition between two hyperfine levels of the 2S state of atomic hydrogen. Such a transition, with {Delta}l = 0, violates parity symmetry. The technique used was to induce an interference between the forbidden transition and a parity-allowed E1 transition polarized by a DC electric field. The two induced transitions were driven coherently in a single microwave cavity. A magnetic field was used to shift the atoms into resonance with the RF radiation and to make the 2S and 2P states degenerate in energy, which would maximize any parity-violating mixing between these states. The measurements were made by passing a beam of hydrogen through the microwave cavity, and monitoring the state of the emerging atoms. To separate the parity-violating component of the transition rate from the parity-conserving part, the change in the transition rate was monitored when the handedness of the interaction region was reversed. From the transition asymmetry it was possible to extract the size of the proton-spin dependent part of a general parity-violating interaction between an electron and a proton. This can be stated in terms of a dimensionless constant C{sub 2}. The result of this experiment is C{sub 2p} = 1.5 {plus_minus} 22. The error bound represents a 95% confidence level and is an improvement of an order of magnitude over previous limits set by similar experiments in hydrogen.

  17. Electric and magnetic dipole excitations to bound states in 70,72,74,76Ge

    NASA Astrophysics Data System (ADS)

    Jung, A.; Lindenstruth, S.; Schacht, H.; Starck, B.; Stock, R.; Wesselborg, C.; Heil, R. D.; Kneissl, U.; Margraf, J.; Pitz, H. H.; Steiper, F.

    1995-02-01

    The nuclei 70,72,74,76Ge were studied by nuclear resonance fluorescence (NRF) experiments. Partially linearly polarized and unpolarized bremsstrahlung of 9 to 14 MeV endpoint energy was used at the Giessen 65 MeV electron linear accelerator; unpolarized bremsstrahlung of 4 MeV endpoint energy was used at the Stuttgart Dynamitron. The scattered photons were detected by Ge γ-ray spectrometers with high energy resolution. Multipolarities were determined by measuring the angular correlations between the beam and the scattered γ rays at different scattering angles. Precise excitation energies and ground-state decay widths of numerous (> 120) previously unknown spin-1 states were extracted. For 65 ground-state transitions (20 M1 transitions, 45 E1 transitions) parities were assigned, in a model-independent way, by polarized bremsstrahlung. A detailed distribution of electric and magnetic dipole strength in the even Ge isotopes was established.

  18. Current status of the measurement of the anapole moment

    NASA Astrophysics Data System (ADS)

    Sheng, Dong; Perez Galvan, Adrian; Hood, Jonathan; Orozco, Luis

    2009-05-01

    We present the current status of the experimental effort towards the measurement of the anapole moment in different isotopes of francium. The anapole is a parity-violating, time-reversal conserving nuclear moment that arises from the weak interaction among nucleons. Due to the electromagnetic interaction between electrons and nucleons, atomic physics gives the unique possibility to probe the weak interaction in the low energy regime. Our experimental scheme involves driving a parity forbidden E1 transition between hyperfine ground states in a series of francium isotopes inside a blue detuned dipole trap at the electric antinode of a microwave cavity. The experiment will make use of the ISAC radioactive beam facility at TRIUMF. The system is currently being tested with rubidium.

  19. Progress on the measurement of the francium anapole moment

    NASA Astrophysics Data System (ADS)

    Sheng, Dong; Hood, Jonathan; Lynam, Steven; Orozco, Luis; Gomez, Eduardo; Aubin, Seth; Gwinner, Gerald; Behr, John; Pearson, Matthew; Jackson, Peter; Melconian, Dan; Flambaum, Victor; Sprouse, Gene

    2010-03-01

    We present the current status of the experimental effort towards the measurement of the anapole moment in francium. The anapole is a parity violating, time-reversal conserving nuclear moment that arises from the weak interaction among nucleons. The anapole moment is nuclear spin dependent (nsd) and sensitive to the configuration of nuclear structure. Our experimental scheme is to perform a direct measurement of the nsd parity violation, by driving a parity forbidden E1 transition between hyperfine ground states in a series of francium isotopes inside a blue detuned dipole trap at the electric anti-node of a microwave cavity. We explore theoretical aspects and experimental requirements on the possible tests using rubidium isotopes. The experiment will be at the ISAC radioactive beam facility of TRIUMF. Work supported by NSF and DOE USA, NSERC and NRC Canada, CONACYT Mexico.

  20. New Features of Shape Coexistence in Sm152

    NASA Astrophysics Data System (ADS)

    Garrett, P. E.; Kulp, W. D.; Wood, J. L.; Bandyopadhyay, D.; Choudry, S.; Dashdorj, D.; Lesher, S. R.; McEllistrem, M. T.; Mynk, M.; Orce, J. N.; Yates, S. W.

    2009-08-01

    Excited states in Sm152 have been investigated with the Sm152(n,n'γ) reaction. The lowest four negative-parity band structures have been characterized in detail with respect to their absolute decay properties. Specifically, a new Kπ=0- band has been assigned with its 1- band head at 1681 keV. This newly observed band has a remarkable similarity in its E1 transition rates for decay to the first excited Kπ=0+ band at 684 keV to the lowest Kπ=0- band and its decay to the ground-state band. Based on these decay properties, as well as energy considerations, this new band is assigned as a Kπ=0- octupole excitation based on the Kπ=02+ state. An emerging pattern of repeating excitations built on the 02+ level similar to those built on the ground state may indicate that Sm152 is a complex example of shape coexistence rather than a critical point nucleus.

  1. Structure of magnetic resonance in 87Rb atoms

    NASA Astrophysics Data System (ADS)

    Kozlov, A. N.; Zibrov, S. A.; Zibrov, A. A.; Yudin, V. I.; Taichenachev, A. V.; Yakovlev, V. P.; Tsygankov, E. A.; Zibrov, A. S.; Vassiliev, V. V.; Velichansky, V. L.

    2016-05-01

    Magnetic resonance at the F g = 1 rightleftarrows F e = 1 transition of the D 1 line in 87Rb has been studied with pumping and detection by linearly polarized radiation and detection at the double frequency of the radiofrequency field. The intervals of allowed values of the static and alternating magnetic fields in which magnetic resonance has a single maximum have been found. The structure appearing beyond these intervals has been explained. It has been shown that the quadratic Zeeman shift is responsible for the three-peak structure of resonance; the radiofrequency shift results in the appearance of additional extrema in resonance, which can be used to determine the relaxation constant Γ2. The possibility of application in magnetometry has been discussed.

  2. Multipole character of the proposed 220 eV transition in [sup 229]Pa

    SciTech Connect

    Dragoun, O.; Rysavy, M. ); Guenther, C. )

    1993-02-01

    Internal conversion coefficients (ICC's) have been calculated for protactinium and transition energies between 170 eV and 10 keV. The ICC's for [ital E]1 multipolarity show an unusual behavior, which cannot be approximated by an exponential dependence on the transition energy, whereas the ICC's for [ital M]1 and [ital E]2 multipolarities closely follow such a dependence. Using the newly calculated ICC's the unusually strong enhancement'' of a possible 220 eV [ital E]1 transition in [sup 229]Pa proposed earlier is reduced by a factor of [similar to]5, yielding an induced electric dipole moment similar to that observed in the neighboring octupole-deformed isotopes.

  3. Observation of {chi}{sub bJ}(1P,2P) decays to light hadrons

    SciTech Connect

    Asner, D. M.; Edwards, K. W.; Reed, J.; Briere, R. A.; Tatishvili, G.; Vogel, H.; Onyisi, P. U. E.; Rosner, J. L.; Alexander, J. P.; Cassel, D. G.; Duboscq, J. E.; Ehrlich, R.; Fields, L.; Galik, R. S.; Gibbons, L.; Gray, R.; Gray, S. W.; Hartill, D. L.; Heltsley, B. K.; Hertz, D.

    2008-11-01

    Analyzing {upsilon}(nS) decays acquired with the CLEO detector operating at the CESR e{sup +}e{sup -} collider, we measure for the first time the product branching fractions B[{upsilon}(nS){yields}{gamma}{chi}{sub bJ}((n-1)P)]B[{chi}{sub bJ}(n-1)P){yields}X{sub i}] for n=2 and 3, where X{sub i} denotes, for each i, one of the 14 exclusive light-hadron final states for which we observe significant signals in both {chi}{sub bJ}(1P) and {chi}{sub bJ}(2P) decays. We also determine upper limits for the electric dipole (E1) transitions {upsilon}(3S){yields}{gamma}{chi}{sub bJ}(1P)

  4. Observation of electric quadrupole transitions to Rydberg nd states of ultracold rubidium atoms

    SciTech Connect

    Tong, D.; Farooqi, S. M.; Kempen, E. G. M. van; Pavlovic, Z.; Stanojevic, J.; Cote, R.; Eyler, E. E.; Gould, P. L.

    2009-05-15

    We report the observation of dipole-forbidden, but quadrupole-allowed, one-photon transitions to high-Rydberg states in Rb. Using pulsed uv excitation of ultracold atoms in a magneto-optical trap, we excite 5s{yields}nd transitions over a range of principal quantum numbers n=27-59. Compared to dipole-allowed (E1) transitions from 5s{yields}np, these E2 transitions are weaker by a factor of approximately 2000. We also report measurements of the anomalous np{sub 3/2}:np{sub 1/2} fine-structure transition strength ratio for n=28-75. Both results are in agreement with theoretical predictions.

  5. Isospin Symmetry Along The N=Z Line In The sd Shell

    SciTech Connect

    Della Vedova, F.; Lenzi, S. M.; Farnea, E.; Nespolo, M.; Bazzacco, D.; Brandolini, F.; Lunardi, S.; Menegazzo, R.; Rossi Alvarez, C.; Ur, C.A.; Ionescu-Bujor, M.; Bucurescu, D.; Iordachescu, A.; Marginean, N.; De Angelis, G.; Axiotis, M.; Napoli, D. R.; Bizzeti-Sona, A.; Bizzeti, P.G.

    2005-04-05

    Excited states have been studied in sd-shell nuclei following the 16O (70 MeV) + 24Mg (400 {mu}g/cm2) fusion-evaporation reaction. The GASP spectrometer in conjunction with the charged-particle detector ISIS and the Neutron ring allowed the detection of the {gamma}-rays in coincidence with evaporated light particles. New data on the mirror pairs A=31 and A=35 have been obtained. In particular, the comparison between the level schemes of 35Ar and 35Cl has confirmed the importance of the electromagnetic spin-orbit term, which explains the large Mirror Energy Difference values. Evidence of isospin mixing can be deduced from the E1 transitions.

  6. Electromagnetic selection rules in the triangular α-cluster model of 12C

    NASA Astrophysics Data System (ADS)

    Stellin, G.; Fortunato, L.; Vitturi, A.

    2016-08-01

    After recapitulating the procedure to find the bands and the states occurring in the {{ D }}3h alpha-cluster model of 12C in which the clusters are placed at the vertexes of an equilateral triangle, we obtain the selection rules for electromagnetic transitions. While the alpha-cluster structure leads to the cancellation of E1 transitions, the approximations carried out in deriving the rotational-vibrational Hamiltonian lead to the disappearance of M1 transitions. Furthermore, although in general the lowest active modes are E2, E3, ... and M2, M3, ..., the cancellation of M2, M3 and M5 transitions between certain bands also occur as a result of the application of group theoretical techniques drawn from molecular physics. These implications can be very relevant for the spectroscopic analysis of γ-ray spectra of 12C.

  7. Radiative n 14N capture at astrophysical energies

    NASA Astrophysics Data System (ADS)

    Dubovichenko, S. B.

    2013-06-01

    In the potential cluster model with forbidden states and classification of orbital cluster states according to Young's schemes, the possibility is considered of describing the experimental data for the total cross sections of radiative n 14N capture at energies from 25.0 meV (25•10-3 eV) to 1.0 MeV. It is shown that on the whole it is possible to successfully explain the behavior of these cross sections outside the resonant energy region on the basis of the E1 transition from the 2S1/2 scattering wave with zero phase to the bound 2Р1/2 state of the 15N nucleus in the n14N channel.

  8. Evolution of octupole correlations in 123Ba

    NASA Astrophysics Data System (ADS)

    Chen, X. C.; Zhao, J.; Xu, C.; Hua, H.; Shneidman, T. M.; Zhou, S. G.; Wu, X. G.; Li, X. Q.; Zhang, S. Q.; Li, Z. H.; Liang, W. Y.; Meng, J.; Xu, F. R.; Qi, B.; Ye, Y. L.; Jiang, D. X.; Cheng, Y. Y.; He, C.; Sun, J. J.; Han, R.; Niu, C. Y.; Li, C. G.; Li, P. J.; Wang, C. G.; Wu, H. Y.; Li, Z. H.; Zhou, H.; Hu, S. P.; Zhang, H. Q.; Li, G. S.; He, C. Y.; Zheng, Y.; Li, C. B.; Li, H. W.; Wu, Y. H.; Luo, P. W.; Zhong, J.

    2016-08-01

    High-spin states of 123Ba have been studied via the 108Cd(19F,3 n p )123Ba fusion-evaporation reaction at a beam energy of 90 MeV. Several E 1 transitions linking the positive-parity ν (d5 /2+g7 /2) band and negative-parity ν h11 /2 band are observed in 123Ba for the first time. Evidence for the existence of octupole correlations in 123Ba is presented based on the systematic comparisons of the B (E 1 )/B (E 2 ) branching ratios and the energy displacements in odd-A Ba isotopes. The characteristics of octupole correlation in the odd-A Ba,125123 are explained by the state-of-the-art multidimensionally-constrained relativistic mean-field model and cluster model based on the dinuclear system concept.

  9. Observation of χcJ decays to ΛΛ¯¯¯π⁺π⁻

    SciTech Connect

    Ablikim, M.; Achasov, M. N.; Ambrose, D. J.; An, F. F.; An, Q.; An, Z. H.; Bai, J. Z.; Ban, Y.; Becker, J.; Bennett, J. V.; Bertani, M.; Bian, J. M.; Boger, E.; Bondarenko, O.; Boyko, I.; Briere, R. A.; Bytev, V.; Cai, X.; Cakir, O.; Calcaterra, A.; Cao, G. F.; Cetin, S. A.; Chang, J. F.; Chelkov, G.; Chen, G.; Chen, H. S.; Chen, J. C.; Chen, M. L.; Chen, S. J.; Chen, Y. B.; Cheng, H. P.; Chu, Y. P.; Cronin-Hennessy, D.; Dai, H. L.; Dai, J. P.; Dedovich, D.; Deng, Z. Y.; Denig, A.; Denysenko, I.; Destefanis, M.; Ding, W. M.; Ding, Y.; Dong, L. Y.; Dong, M. Y.; Du, S. X.; Fang, J.; Fang, S. S.; Fava, L.; Feldbauer, F.; Feng, C. Q.; Ferroli, R. B.; Fu, C. D.; Fu, J. L.; Gao, Y.; Geng, C.; Goetzen, K.; Gong, W. X.; Gradl, W.; Greco, M.; Gu, M. H.; Gu, Y. T.; Guan, Y. H.; Guo, A. Q.; Guo, L. B.; Guo, Y. P.; Han, Y. L.; Harris, F. A.; He, K. L.; He, M.; He, Z. Y.; Held, T.; Heng, Y. K.; Hou, Z. L.; Hu, H. M.; Hu, J. F.; Hu, T.; Huang, G. M.; Huang, J. S.; Huang, X. T.; Huang, Y. P.; Hussain, T.; Ji, C. S.; Ji, Q.; Ji, X. B.; Ji, X. L.; Jiang, L. L.; Jiang, X. S.; Jiao, J. B.; Jiao, Z.; Jin, D. P.; Jin, S.; Jing, F. F.; Kalantar-Nayestanaki, N.; Kavatsyuk, M.; Kuehn, W.; Lai, W.; Lange, J. S.; Li, C. H.; Li, Cheng; Li, Cui; Li, D. M.; Li, F.; Li, G.; Li, H. B.; Li, J. C.; Li, K.; Li, Lei; Li, Q. J.; Li, S. L.; Li, W. D.; Li, W. G.; Li, X. L.; Li, X. N.; Li, X. Q.; Li, X. R.; Li, Z. B.; Liang, H.; Liang, Y. F.; Liang, Y. T.; Liao, G. R.; Liao, X. T.; Liu, B. J.; Liu, C. L.; Liu, C. X.; Liu, C. Y.; Liu, F. H.; Liu, Fang; Liu, Feng; Liu, H.; Liu, H. B.; Liu, H. H.; Liu, H. M.; Liu, H. W.; Liu, J. P.; Liu, K. Y.; Liu, Kai; Liu, P. L.; Liu, Q.; Liu, S. B.; Liu, X.; Liu, X. H.; Liu, Y. B.; Liu, Z. A.; Liu, Zhiqiang; Liu, Zhiqing; Loehner, H.; Lu, G. R.; Lu, H. J.; Lu, J. G.; Lu, Q. W.; Lu, X. R.; Lu, Y. P.; Luo, C. L.; Luo, M. X.; Luo, T.; Luo, X. L.; Lv, M.; Ma, C. L.; Ma, F. C.; Ma, H. L.; Ma, Q. M.; Ma, S.; Ma, T.; Ma, X. Y.; Ma, Y.; Maas, F. E.; Maggiora, M.; Malik, Q. A.; Mao, Y. J.; Mao, Z. P.; Messchendorp, J. G.; Min, J.; Min, T. J.; Mitchell, R. E.; Mo, X. H.; Morales Morales, C.; Motzko, C.; Muchnoi, N. Yu.; Muramatsu, H.; Nefedov, Y.; Nicholson, C.; Nikolaev, I. B.; Ning, Z.; Olsen, S. L.; Ouyang, Q.; Pacetti, S.; Park, J. W.; Pelizaeus, M.; Peng, H. P.; Peters, K.; Ping, J. L.; Ping, R. G.; Poling, R.; Prencipe, E.; Qi, M.; Qian, S.; Qiao, C. F.; Qin, X. S.; Qin, Y.; Qin, Z. H.; Qiu, J. F.; Rashid, K. H.; Rong, G.; Ruan, X. D.; Sarantsev, A.; Schaefer, B. D.; Schulze, J.; Shao, M.; Shen, C. P.; Shen, X. Y.; Sheng, H. Y.; Shepherd, M. R.; Song, X. Y.; Spataro, S.; Spruck, B.; Sun, D. H.; Sun, G. X.; Sun, J. F.; Sun, S. S.; Sun, Y. J.; Sun, Y. Z.; Sun, Z. J.; Sun, Z. T.; Tang, C. J.; Tang, X.; Tapan, I.; Thorndike, E. H.; Toth, D.; Ullrich, M.; Varner, G. S.; Wang, B.; Wang, B. Q.; Wang, K.; Wang, L. L.; Wang, L. S.; Wang, M.; Wang, P.; Wang, P. L.; Wang, Q.; Wang, Q. J.; Wang, S. G.; Wang, X. L.; Wang, Y. D.; Wang, Y. F.; Wang, Y. Q.; Wang, Z.; Wang, Z. G.; Wang, Z. Y.; Wei, D. H.; Weidenkaff, P.; Wen, Q. G.; Wen, S. P.; Werner, M.; Wiedner, U.; Wu, L. H.; Wu, N.; Wu, S. X.; Wu, W.; Wu, Z.; Xia, L. G.; Xiao, Z. J.; Xie, Y. G.; Xiu, Q. L.; Xu, G. F.; Xu, G. M.; Xu, H.; Xu, Q. J.; Xu, X. P.; Xu, Z. R.; Xue, F.; Xue, Z.; Yan, L.; Yan, W. B.; Yan, Y. H.; Yang, H. X.; Yang, Y.; Yang, Y. X.; Ye, H.; Ye, M.; Ye, M. H.; Yu, B. X.; Yu, C. X.; Yu, J. S.; Yu, S. P.; Yuan, C. Z.; Yuan, Y.; Zafar, A. A.; Zallo, A.; Zeng, Y.; Zhang, B. X.; Zhang, B. Y.; Zhang, C. C.; Zhang, D. H.; Zhang, H. H.; Zhang, H. Y.; Zhang, J. Q.; Zhang, J. W.; Zhang, J. Y.; Zhang, J. Z.; Zhang, S. H.; Zhang, X. J.; Zhang, X. Y.; Zhang, Y.; Zhang, Y. H.; Zhang, Y. S.; Zhang, Z. P.; Zhang, Z. Y.; Zhao, G.; Zhao, H. S.; Zhao, J. W.; Zhao, K. X.; Zhao, Lei; Zhao, Ling; Zhao, M. G.; Zhao, Q.; Zhao, S. J.; Zhao, T. C.; Zhao, X. H.; Zhao, Y. B.; Zhao, Z. G.; Zhemchugov, A.; Zheng, B.; Zheng, J. P.; Zheng, Y. H.; Zhong, B.; Zhong, J.; Zhou, L.; Zhou, X. K.; Zhou, X. R.; Zhu, C.; Zhu, K.; Zhu, K. J.; Zhu, S. H.; Zhu, X. L.; Zhu, X. W.; Zhu, Y. C.; Zhu, Y. M.; Zhu, Y. S.; Zhu, Z. A.; Zhuang, J.; Zou, B. S.; Zou, J. H.

    2012-09-13

    Decays of the χcJ states (J=0, 1, 2) to ΛΛ¯¯¯π⁺π⁻, including processes with intermediate Σ(1385), are studied through the E1 transition ψ'→γχcJ using 106×10⁶ ψ' events collected with the BESIII detector at BEPCII. This is the first observation of χcJ decays to the final state ΛΛ¯¯¯π⁺π⁻. The branching ratio of the intermediate process χcJ→Σ(1385)±Σ¯¯¯(1385) is also measured for the first time, and the results agree with the theoretical predictions based on the color-octet effect.

  10. QED calculation of transition probabilities in two-electron ions

    NASA Astrophysics Data System (ADS)

    Andreev, Oleg Yu.; Labzowsky, Leonti N.; Plunien, Günter

    2009-03-01

    An accurate QED calculation of transition probabilities for the low-lying two-electron configurations of multicharged ions is presented. The calculation is performed for the nondegenerate states (1s2s)S31 , (1s2p3/2)P32 ( M1 and M2 transitions, respectively) and for the quasidegenerate states (1s2p)P11 , (1s2p)P31 ( E1 transitions) decaying to the ground state (1s1s)S10 . Two-electron ions with nuclear-charge numbers Z=10-92 are considered. The line profile approach is employed for the description of the process in multicharged ions within the framework of QED.

  11. Proposed s =±1 octupole bands in 140Xe

    NASA Astrophysics Data System (ADS)

    Huang, Y.; Zhu, S. J.; Hamilton, J. H.; Wang, E. H.; Ramayya, A. V.; Xiao, Z. G.; Li, H. J.; Luo, Y. X.; Rasmussen, J. O.; Ter-Akopian, G. M.; Oganessian, Yu. Ts.

    2016-06-01

    Level structures of neutron-rich 140Xe nucleus have been reinvestigated by using a triple γ coincidence study from the spontaneous fission of 252Cf. Several new levels and transitions are identified. The previously observed s =+1 octupole band structure is confirmed and expanded. Another set of the Δ I =2 positive and negative parity bands connected by strong E 1 transitions is proposed as the s =-1 octupole band structure. Thus, the s =±1 doublet octupole bands are completed in 140Xe. The experimental B (E 1 )/B (E 2 ) branching ratios indicate that the octupole correlations in 140Xe are weak. The other characteristics of the s =±1 octupole bands have been discussed.

  12. Measurement of lifetimes in {sup 46}V with the EUROBALL {gamma}-ray spectrometer

    SciTech Connect

    Jessen, K.; Moeller, O.; Dewald, A.; Brentano, P. von; Fitzler, A.; Jolie, J.; Saha, B.; Petkov, P.; Brandolini, F.; Gadea, A.; Lenzi, S. M.; De Angelis, G.; Farnea, E.; Napoli, D. R.; Gall, B. J. P.

    2006-08-15

    In {sup 46}V picosecond lifetimes were determined using the recoil distance Doppler-shift technique with the Cologne plunger device coupled to the EUROBALL IV spectrometer. The experiment was carried out using the {sup 24}Mg({sup 28}Si, {alpha}pn) reaction at 110 MeV at the Strasbourg VIVITRON accelerator. Subsequently the differential decay curve method in coincidence mode was employed to derive lifetimes for four excited states in the K{sup {pi}}=0{sup -} band. The resulting transition probabilities give a comparison of isospin allowed and forbidden E1 transitions, which clarifies the decay properties of the 2{sup -},T=0 state. Furthermore the B(E2) values within the K{sup {pi}}=0{sup -} band are discussed.

  13. Recent Results on Hadron Spectroscopy and Charmonium from BESIII

    SciTech Connect

    Liu Fang

    2011-10-24

    pp-bar mass threshold enhancement is studied using the data sample of J/{psi} and y(2S) collected with BESIII detector in 2009. The enhancement is evident in J/{psi} radiative decay, which is consistent with BESII results. No significance narrow enhancement is observed in {psi}(2S) radiative decay. The structure of Xlpar;1835 is also confirmed in J/{psi} = {gamma}{eta}'{pi}{sub +}{pi}{sup -} at BESIII. The spin-singlet P-wave charmonium state h{sub c}(1P) is studied at BESIII, the mass spectra recoiling against the {pi}{sup 0} in the decay {psi}(2S) = {pi}{sup 0}h{sub c} both in h{sub c} inclusive decay and in the final states with a tagged E1-transition photon from h{sub c} {yields} {gamma}{eta}{sub r} are fitted to extract the number of hc signals.

  14. Electric and Magnetic Dipole States in ^238U

    NASA Astrophysics Data System (ADS)

    Hammond, S. L.; Adekola, A.; Angell, C. T.; Karwowski, H. J.; Howell, C. R.; Kwan, E.; Rusev, G.; Tonchev, A. P.; Tornow, W.; Kelley, J. H.

    2010-11-01

    An investigation of dipole states in ^238U is important for the fundamental understanding of its structure. Precise experimental information on the distribution of M1 and E1 transitions in ^238U has been obtained using the nuclear resonance fluorescence technique at the High-Intensity γ-ray Source at the Triangle Universities Nuclear Laboratory. Using 100% linearly-polarized, monoenergetic γ-ray beams between incident energies of 2.0 - 5.5 MeV, the spin, parity, width, and γ-strength of the ground-state deexcitations were determined. These measurements will form a unique data set that can be used for comparison with theoretical models of collective excitations in heavy, deformed nuclei. The data can also provide isotope-specific signatures to search for special nuclear materials.

  15. Systematics of photon strength functions

    NASA Astrophysics Data System (ADS)

    Firestone, Richard

    2015-10-01

    The photon strength of high energy E1 transitions is well described by Brink-Axel theory based on the contribution of the Giant Dipole Resonance. No adequate theory is available for M1 and E2 transitions which do not generally compete strongly with high energy E1 transitions. Measurements with the 57Fe(3He,3He') reaction at the Oslo cyclotron have revealed that the photon strength below 2 MeV greatly exceeds BA predictions. Similar results have been found for numerous other nuclides. In this paper I will discuss my analysis of the 56Fe(n,γ)57Fe reaction which we investigated with both cold neutrons from the Budapest Reactor and thermal neutrons from the Rez Reactor (Prague). A >99% complete 57Fe capture γ-ray decay scheme containing 449 γ-rays deexciting 100 levels has been constructed on the basis of γ-ray singles and γγ -coincidence data. The photon strengths for 90 primary γ-rays with energies ranging from 92-7646 keV were calculated and compared with the predictions of Brink-Axel (BA) theory. Excellent agreement has been attained for the high energy transitions while the strength below 2 MeV exceeds BA predictions confirming the earlier Oslo (3He,3He' γ) results. Photon strengths for another 95 secondary M1, E1, and E2 γ-rays were also determined to also exceed BA predictions for transitions below 4 MeV. The dependence of photon strength on level energy and the statistical distribution of photon strengths will also be discussed in this talk.

  16. Oscillator strengths and transition probabilities from the Breit–Pauli R-matrix method: Ne IV

    SciTech Connect

    Nahar, Sultana N.

    2014-09-15

    The atomic parameters–oscillator strengths, line strengths, radiative decay rates (A), and lifetimes–for fine structure transitions of electric dipole (E1) type for the astrophysically abundant ion Ne IV are presented. The results include 868 fine structure levels with n≤ 10, l≤ 9, and 1/2≤J≤ 19/2 of even and odd parities, and the corresponding 83,767 E1 transitions. The calculations were carried out using the relativistic Breit–Pauli R-matrix method in the close coupling approximation. The transitions have been identified spectroscopically using an algorithm based on quantum defect analysis and other criteria. The calculated energies agree with the 103 observed and identified energies to within 3% or better for most of the levels. Some larger differences are also noted. The A-values show good to fair agreement with the very limited number of available transitions in the table compiled by NIST, but show very good agreement with the latest published multi-configuration Hartree–Fock calculations. The present transitions should be useful for diagnostics as well as for precise and complete spectral modeling in the soft X-ray to infra-red regions of astrophysical and laboratory plasmas. -- Highlights: •The first application of BPRM method for accurate E1 transitions in Ne IV is reported. •Amount of atomic data (n going up to 10) is complete for most practical applications. •The calculated energies are in very good agreement with most observed levels. •Very good agreement of A-values and lifetimes with other relativistic calculations. •The results should provide precise nebular abundances, chemical evolution etc.

  17. Beta Decay of 153Nd and Reflection Asymmetric Deformation in 153Pm

    NASA Astrophysics Data System (ADS)

    Taniguchi, Akihiro; Ikuta, Tomohiko; Osa, Akihiko; Yamamoto, Hiroshi; Kawade, Kiyoshi; Ruan, Jian-Zhi; Yamada, Shigeru; Kawase, Yoichi; Okano, Kotoyuki

    1996-12-01

    The level structure of 153Pm has been studied from the decay of 153Nd. The radioactivities of 153Nd were separated from the fission products of 235U using the upgraded KUR-ISOL. A precise decay scheme of 153Nd has been constructed up to 2 MeV and 115 γ-rays and 36 levels were involved in the decay scheme, in which 107 γ-rays and 28 levels were newly observed. The multipolarities and E2/M1 mixing ratios of 11 γ-transitions were deduced from the measurement of internal conversion electrons. From the results of the angular correlation measurements, the spin values of 450.5, 105.4 and 32.3 keV levels were deduced to be 3/2+, 7/2+ and 5/2+, respectively and the previous assignments were confirmed. The half-lives of 32.3 and 105.4 keV levels were determined to be 1.2(1) ns and 0.44(2) ns, respectively and the enhanced E1 transitions with B( E1)=10-3˜10-4 W.u. were observed. The 153Pm level structure was compared with the result of a calculation with a rotation-vibration coupling model (RVCM) and it was found that 153Pm has a typical nuclear structure of the deformed nucleus. Moreover, the observation of enhanced E1 transitions between parity doublet bands indicates the possibility of the existence of the reflection asymmetric deformation in 153Pm.

  18. Evidence for octupole vibration in the superdeformed well of {sup 190}Hg from eurogam

    SciTech Connect

    Crowell, B.; Carpenter, M.P.; Janssens, R.V.F.

    1995-08-01

    Gammasphere experiments in 1993-94 brought to light the existence of an excited superdeformed (SD) band in {sup 190}Hg with the unusual property of decaying entirely to the lowest (yrast) SD band over 3-4 transitions, rather than to the normally deformed states as is usually the case in the A {approximately} 150 and A {approximately} 190 regions of superdeformation. Although M1 transitions between signature-partner SD bands were previously observed in {sup 193}Hg, no such mechanism was available to explain the situation in the even-even nucleus {sup 190}Hg, whose yrast SD band has no signature partner. The best explanation appears to lie in long-standing theoretical predictions that the SD minimum in the potential energy surface would be quite soft with respect to octupole vibrations. This would lead to enhanced E1 transitions connecting the one-phonon and zero-phonon states. The data and this interpretation were published. A shortcoming of the Gammasphere experiments was that they did not allow the definitive measurement of the energies of the gamma-ray transitions connecting the two bands, due to the very weak population of the excited band ({approximately}0.05% of the {sup 190}Hg channel) and also partly, we believed, to the angular distributions of the transitions, which were peaked near 90 degrees, where Gammasphere had few detectors.

  19. Influence of the N=50 neutron core on dipole excitations in 87Rb

    NASA Astrophysics Data System (ADS)

    Käubler, L.; Schilling, K. D.; Schwengner, R.; Dönau, F.; Grosse, E.; Belic, D.; von Brentano, P.; Bubner, M.; Fransen, C.; Grinberg, M.; Kneissl, U.; Kohstall, C.; Linnemann, A.; Matschinsky, P.; Nord, A.; Pietralla, N.; Pitz, H. H.; Scheck, M.; Stedile, F.; Werner, V.

    2002-05-01

    Dipole excitations in the semimagic N=50 nucleus 87Rb were investigated at the Stuttgart Dynamitron facility using bremsstrahlung with an end-point energy of 4.0 MeV. The widths Γ or the reduced excitation probabilities B(Π1)↑ of 18 states were determined for the first time. The magnetic dipole excitations are well reproduced in the framework of the shell model, however, these calculations cannot describe the observed electric dipole excitations. The 1/2+ state at 3060 keV is proposed to be the weak coupling of an f5/2 proton hole to the 3- octupole vibrational state in the N=50 core 88Sr. The relatively strong E1 transition from that state to the ground state is explained as mainly the neutron h11/2-->g9/2 transition. The breakup of the N=50 core and neutron excitations into the h11/2 shell are essential to describe electric dipole excitations, but neutron-core excitations do not play an important role for the structure of magnetic dipole excitations.

  20. Novel Manifestation of {alpha}-Clustering Structures: New '{alpha}+{sup 208}Pb' States in {sup 212}Po Revealed by Their Enhanced E1 Decays

    SciTech Connect

    Astier, A.; Porquet, M.-G.; Petkov, P.; Delion, D. S.; Schuck, P.

    2010-01-29

    Excited states in {sup 212}Po were populated by {alpha} transfer using the {sup 208}Pb({sup 18}O,{sup 14}C) reaction, and their deexcitation {gamma} rays were studied with the Euroball array. Several levels were found to decay by a unique E1 transition (E{sub {gamma}}<1 MeV) populating the yrast state with the same spin value. Their lifetimes were measured by the Doppler-shift attenuation method. The values, found in the range 0.1-1.4 ps, lead to very enhanced transitions, B(E1)=2x10{sup -2}-1x10{sup -3} W.u. These results are discussed in terms of an {alpha}-cluster structure which gives rise to states with non-natural-parity values, provided that the composite system cannot rotate collectively, as expected in the '{alpha}+{sup 208}Pb' case. Such states due to the oscillatory motion of the {alpha}-core distance are observed for the first time.

  1. Preparation of the anapole moment measurement in a chain of isotopes

    NASA Astrophysics Data System (ADS)

    Sheng, Dong; Hood, Jonathan; Orozco, Luis

    2010-02-01

    We present the current status of the experimental effort towards the measurement of the anapole moment in different isotopes of francium. The anapole is a parity violating, time reversal conserving nuclear moment that arises from the weak interaction among nucleons, and should be sensitive to the changes in the nuclear structure configuration among the isotopes. The anapole is a unique probe of the weak interaction in the presence of the strong interaction. The system is currently being tested with rubidium and we have analyzed the sensitivity to measurements with a chain of Rb isotopes. Our experimental scheme involves a collection of cold atoms in a blue-detuned dipole trap located at the anti-node of a microwave cavity. The standing wave would drive a parity forbidden E1 transition between hyperfine ground states, interfering with an allowed transition. The rate of transitions depends on the positive or negative handedness of the apparatus and the measurement of their difference is proportional to the anapole moment. The experiment will use of the ISAC radioactive beam facility at TRIUMF. )

  2. Quasiparticle-random-phase approximation treatment of the transverse wobbling mode reconsidered

    NASA Astrophysics Data System (ADS)

    Frauendorf, S.; Dönau, F.

    2015-12-01

    The quasiparticle-random-phase approximation is used to study the properties of the wobbling bands in 163Lu. Assuming that the wobbling mode represents pure isoscalar orientation oscillations results in too low wobbling frequencies and transition probabilities between the one- and zero-phonon wobbling bands that are strongly collective but yet too weak for B (E2 ) out and too strong for B (M1 ) out . The inclusion of an LL interaction, which couples the wobbling mode to the scissors mode, generates the right upshift of the wobbling frequencies and the right suppression of the B (M1 ) out values toward the experimental values, but does not change the B (E2 ) out values. In analogy to the quenching of low-energy E 1 transition by coupling to the isovector giant dipole resonance, a general reduction of the M 1 transitions between quasiparticle configurations caused by coupling to the scissors mode is suggested. The small B (E2 ) out values are related to small triaxiality of the density distribution, which is found by all mean field calculations for the triaxial strongly deformed nuclei in the mass 160 region.

  3. New Features of Shape Coexistence in {sup 152}Sm

    SciTech Connect

    Garrett, P. E.; Kulp, W. D.; Wood, J. L.; Bandyopadhyay, D.; Choudry, S.; Lesher, S. R.; McEllistrem, M. T.; Mynk, M.; Orce, J. N.; Yates, S. W.; Dashdorj, D.

    2009-08-07

    Excited states in {sup 152}Sm have been investigated with the {sup 152}Sm(n,n{sup '}gamma) reaction. The lowest four negative-parity band structures have been characterized in detail with respect to their absolute decay properties. Specifically, a new K{sup p}i=0{sup -} band has been assigned with its 1{sup -} band head at 1681 keV. This newly observed band has a remarkable similarity in its E1 transition rates for decay to the first excited K{sup p}i=0{sup +} band at 684 keV to the lowest K{sup p}i=0{sup -} band and its decay to the ground-state band. Based on these decay properties, as well as energy considerations, this new band is assigned as a K{sup p}i=0{sup -} octupole excitation based on the K{sup p}i=0{sub 2}{sup +} state. An emerging pattern of repeating excitations built on the 0{sub 2}{sup +} level similar to those built on the ground state may indicate that {sup 152}Sm is a complex example of shape coexistence rather than a critical point nucleus.

  4. Coherent quadrupole-octupole modes and split parity-doublet spectra in odd-A nuclei

    SciTech Connect

    Minkov, N.; Drenska, S.; Yotov, P.; Lalkovski, S.; Bonatsos, D.; Scheid, W.

    2007-09-15

    A collective model describing coherent quadrupole-octupole oscillations and rotations with a Coriolis coupling between the even-even core and the unpaired nucleon is applied to odd nuclei. The particle-core coupling provides a parity-doublet structure of the spectrum, whereas the quadrupole-octupole motion leads to a splitting of the doublet energy levels. The formalism successfully reproduces the split parity-doublet spectra and the attendant B(E1) and B(E2) transition probabilities in a wide range of odd-A nuclei. It provides estimations for the influence of the Coriolis interaction on the collective motion and subsequently for the value of angular momentum projection K on which the spectrum is built. The analysis of the energy splitting and B(E1) transition probabilities between opposite parity counterparts suggests degenerate doublet structures at high angular momenta. The study provides information about the evolution of quadrupole-octupole collectivity in odd-mass nuclei.

  5. Hyperfine-induced electric dipole contributions to the electric octupole and magnetic quadrupole atomic clock transitions

    NASA Astrophysics Data System (ADS)

    Dzuba, V. A.; Flambaum, V. V.

    2016-05-01

    Hyperfine-induced electric dipole contributions may significantly increase probabilities of otherwise very weak electric octupole and magnetic quadrupole atomic clock transitions (e.g., transitions between s and f electron orbitals). These transitions can be used for exceptionally accurate atomic clocks, quantum information processing, and the search for dark matter. They are very sensitive to new physics beyond the standard model, such as temporal variation of the fine-structure constant, the Lorentz invariance, and Einstein equivalence principle violation. We formulate conditions under which the hyperfine-induced electric dipole contribution dominates and perform calculations of the hyperfine structure and E3, M2 and the hyperfine-induced E1 transition rates for a large number of atoms and ions of experimental interest. Due to the hyperfine quenching the electric octupole clock transition in +173Yb is 2 orders of magnitude stronger than that in currently used +171Yb. Some enhancement is found in 13+143Nd, 14+149Pm, 14+147Sm, and 15+147Sm ions.

  6. Study of the soft dipole modes in 140Ce via inelastic scattering of 17O

    NASA Astrophysics Data System (ADS)

    Krzysiek, M.; Kmiecik, M.; Maj, A.; Bednarczyk, P.; Ciemała, M.; Fornal, B.; Grȩbosz, J.; Mazurek, K.; Mȩczyński, W.; Ziȩbliński, M.; Crespi, F. C. L.; Bracco, A.; Benzoni, G.; Blasi, N.; Boiano, C.; Bottoni, S.; Brambilla, S.; Camera, F.; Giaz, A.; Leoni, S.; Million, B.; Morales, A. I.; Nicolini, R.; Pellegri, L.; Riboldi, S.; Vandone, V.; Wieland, O.; De Angelis, G.; Napoli, D. R.; Valiente-Dobon, J. J.; Bazzacco, D.; Farnea, E.; Gottardo, A.; Lenzi, S.; Lunardi, S.; Mengoni, D.; Michelagnoli, C.; Recchia, F.; Ur, C.; Gadea, A.; Huyuk, T.; Barrientos, D.; Birkenbach, B.; Geibel, K.; Hess, H.; Reiter, P.; Steinbach, T.; Wiens, A.; Bürger, A.; Görgen, A.; Guttormsen, M.; Larsen, A. C.; Siem, S.

    2014-05-01

    The main aim of this study was a deeper understanding of the nuclear structure properties of the soft dipole modes in 140Ce, excited via inelastic scattering of weakly bound 17O projectiles. An important aim was to investigate the ‘splitting’ of the PDR into two parts: a low-energy isoscalar component dominated by neutron-skin oscillations and a higher-energy component lying on the tail of the giant dipole resonance of a rather isovector character. This was already observed for this nucleus, investigated in (α, α‧) and (γ, γ‧) experiments. The experiment was performed at Laboratori Nazionali di Legnaro, Italy. Inelastic scattering of 17O ion beam at 20 MeV A-1 was used to excite the resonance modes in the 140Ce target. Gamma-rays were registered by five triple clusters of AGATA-Demonstrator and nine large volume scintillators (LaBr3). The scattered 17O ions were identified by two ΔE - E Si telescopes of the TRACE array mounted inside the scattering chamber. The telescopes consisted of two segmented Si-pad detectors, each of 60 pixels. Very preliminary data have shown a strong domination of the E1 transitions in the ‘pygmy’ region with a character more similar to the one obtained in alpha scattering experiment.

  7. Decay spectroscopy of 160Sm: The lightest four-quasiparticle K isomer

    NASA Astrophysics Data System (ADS)

    Patel, Z.; Podolyák, Zs.; Walker, P. M.; Regan, P. H.; Söderström, P.-A.; Watanabe, H.; Ideguchi, E.; Simpson, G. S.; Nishimura, S.; Browne, F.; Doornenbal, P.; Lorusso, G.; Rice, S.; Sinclair, L.; Sumikama, T.; Wu, J.; Xu, Z. Y.; Aoi, N.; Baba, H.; Bello Garrote, F. L.; Benzoni, G.; Daido, R.; Dombrádi, Zs.; Fang, Y.; Fukuda, N.; Gey, G.; Go, S.; Gottardo, A.; Inabe, N.; Isobe, T.; Kameda, D.; Kobayashi, K.; Kobayashi, M.; Komatsubara, T.; Kojouharov, I.; Kubo, T.; Kurz, N.; Kuti, I.; Li, Z.; Liu, H. L.; Matsushita, M.; Michimasa, S.; Moon, C.-B.; Nishibata, H.; Nishizuka, I.; Odahara, A.; Şahin, E.; Sakurai, H.; Schaffner, H.; Suzuki, H.; Takeda, H.; Tanaka, M.; Taprogge, J.; Vajta, Zs.; Xu, F. R.; Yagi, A.; Yokoyama, R.

    2016-02-01

    The decay of a new four-quasiparticle isomeric state in 160Sm has been observed using γ-ray spectroscopy at the RIBF, RIKEN. The four-quasiparticle state is assigned a 2 π ⊗ 2 ν π5/2- [ 532 ], π5/2+ [ 413 ], ν5/2- [ 523 ], ν7/2+ [ 633 ] configuration. The half-life of this (11+) state is measured to be 1.8(4) μs. The (11+) isomer decays into a rotational band structure, based on a (6-) ν5/2- [ 523 ] ⊗ ν7/2+ [ 633 ] bandhead, consistent with the gK -gR values. This decays to a (5-) two-proton quasiparticle state, which in turn decays to the ground state band. Potential energy surface and blocked-BCS calculations were performed in the deformed midshell region around 160Sm. They reveal a significant influence from β6 deformation and that 160Sm is the best candidate for the lightest four-quasiparticle K isomer to exist in this region. The relationship between reduced hindrance and isomer excitation energy for E1 transitions from multiquasiparticle states is considered with the new data from 160Sm. The E1 data are found to agree with the existing relationship for E2 transitions.

  8. The sarcoplasmic-endoplasmic reticulum Ca(2+)-ATPase (SERCA) is the likely molecular target for the acute toxicity of the brominated flame retardant hexabromocyclododecane (HBCD).

    PubMed

    Al-Mousa, Fawaz; Michelangeli, Francesco

    2014-01-25

    Hexabromocyclododecane (HBCD) is a widely utilised brominated flame retardant (BFR). It has been shown to bio-accumulate within organisms, including man, and possibly cause neurological disorders. The acute neurotoxicity of HBCD, and six other unrelated BFRs, were assessed in SH-SY5Y human neuroblastoma cells by 24h viability assays and HBCD proved to be the most lethal (LC50, 3μM). In addition, the effects of these BFRs were also assessed for their potency at inhibiting the sarcoplasmic-endoplasmic reticulum Ca(2+) ATPase (SERCA) derived from the SH-SY5Y cells and again HBCD was the most potent (IC50, 2.7μM). The data for the other BFRs tested showed a direct correlation (coefficient 0.94) between the potencies of inducing cell death and inhibiting the Ca(2+) ATPase, indicating that SERCA is likely to be the molecular target for acute toxicity. Mechanistic studies of HBCD on the Ca(2+) ATPase suggest that it affects ATP binding, phosphorylation as well as the E2 to E1 transition step. PMID:24189551

  9. Continuum {gamma} rays feeding normal and superdeformed states in Gd nuclei

    SciTech Connect

    Zhu, L.H.; Cinausero, M.; de Angelis, G.; De Poli, M.; Gadea, A.; Napoli, D.R.; Bazzacco, D.; Lunardi, S.; Viesti, G.; Petrache, C.M.; Rossi Alvarez, C.

    1997-03-01

    The feeding mechanism of the superdeformed bands in {sup 147}Gd and {sup 148}Gd has been studied via the {sup 124}Sn + {sup 29}Si reaction at a beam energy of 157 MeV. Using the BGO inner ball of the GASP array, high-energy {gamma} rays have been detected in coincidence with discrete transitions deexciting normal-deformed (ND) and superdeformed (SD) states in the final product nuclei. The slope of the measured high-energy {gamma}-ray spectra depends strongly on the number of emitted neutrons and is somewhat lower for spectra in coincidence with SD bands than for those in coincidence with ND structures. Both observations are qualitatively reproduced by statistical model Monte Carlo calculations, which point out the importance of angular momentum effects in the emission of energetic {gamma} rays. The present data exclude the enhanced population of SD bands when fed through high-energy E1 transitions. {copyright} {ital 1997} {ital The American Physical Society}

  10. Resonance parameters of the first 1/2+ state in Be9 and astrophysical implications

    NASA Astrophysics Data System (ADS)

    Burda, O.; von Neumann-Cosel, P.; Richter, A.; Forssén, C.; Brown, B. A.

    2010-07-01

    Spectra of the Be9(e,e') reaction have been measured at the Superconducting Darmstadt Electron Linear Accelerator at an electron energy of E0=73 MeV and scattering angles of 93° and 141° with high-energy resolution up to excitation energies of Ex=8 MeV. The astrophysically relevant resonance parameters of the first excited 1/2+ state of Be9 have been extracted in a one-level approximation of R-matrix theory, resulting in resonance energy ER=1.748(6) MeV and width ΓR=274(8) keV, which are in good agreement with the latest Be9(γ,n) experiment but with considerably improved uncertainties. However, the reduced B(E1) transition strength deduced from an extrapolation of the (e,e') data to the photon point is smaller by a factor of two. Implications of the new results for possible production of C12 in neutron-rich astrophysical scenarios are discussed.

  11. High spin states in {sup 151,153}Pr, {sup 157}Sm, and {sup 93}Kr

    SciTech Connect

    Hwang, J. K.; Ramayya, A. V.; Hamilton, J. H.; Liu, S. H.; Brewer, N. T.; Luo, Y. X.; Rasmussen, J. O.; Zhu, S. J.; Donangelo, R.

    2010-09-15

    High spin states are observed for the first time in the neutron-rich nuclei {sup 151,153}Pr, {sup 157}Sm, and {sup 93}Kr from the spontaneous fission of {sup 252}Cf. Twenty new transitions in {sup 151}Pr, twelve in {sup 153}Pr, five in {sup 157}Sm, and four in {sup 93}Kr were identified by using x-ray(Pr/Sm)-{gamma}-{gamma} and {gamma}-{gamma}-{gamma} triple coincidences. From the measured total internal conversion coefficients {alpha}{sub T} of four low-energy transitions in {sup 151,153}Pr, we determine that two bands in each nucleus have opposite parity. The interlacing E1 transitions between the bands suggest a form of parity doubling in {sup 151,153}Pr. New bands in {sup 157}Sm and {sup 93}Kr are reported. The half-life of the 354.8 keV state in {sup 93}Kr is measured to be 10(2) ns.

  12. Theoretical study on K, L, and M X-ray transition energies and rates of neptunium and its ions

    NASA Astrophysics Data System (ADS)

    Ismail Abdalla, Saber; Dong, Chen-Zhong; Wang, Xiang-Li; Zhou, Wei-Dong; Wu, Zhong-Wen

    2014-02-01

    The transition energies and electric dipole (E1) transition rates of the K, L, and M lines in neutral Np have been theoretically determined from the MultiConfiguration Dirac—Fock (MCDF) method. In the calculations, the contributions from Breit interaction and quantum electrodynamics (QED) effects (vacuum polarization and self-energy), as well as nuclear finite mass and volume effects, are taken into account. The calculated transition energies and rates are found to be in good agreement with other experimental and theoretical results. The accuracy of the results is estimated and discussed. Furthermore, we calculated the transition energies of the same lines radiating from the decaying transitions of the K-, L-, and M-shell hole states of Np ions with the charge states Np1+ to Np6+ for the first time. We found that for a specific line, the corresponding transition energies relating to all the Np ions are almost the same; it means the outermost electrons have a very small influence on the inner-shell transition processes.

  13. High-K multi-quasiparticle states in 254No

    NASA Astrophysics Data System (ADS)

    Clark, R. M.; Gregorich, K. E.; Berryman, J. S.; Ali, M. N.; Allmond, J. M.; Beausang, C. W.; Cromaz, M.; Deleplanque, M. A.; Dragojević, I.; Dvorak, J.; Ellison, P. A.; Fallon, P.; Garcia, M. A.; Gates, J. M.; Gros, S.; Jeppesen, H. B.; Kaji, D.; Lee, I. Y.; Macchiavelli, A. O.; Morimoto, K.; Nitsche, H.; Paschalis, S.; Petri, M.; Stavsetra, L.; Stephens, F. S.; Watanabe, H.; Wiedeking, M.

    2010-06-01

    We report results from an experiment on the decay of the high-K isomers in 254No. We have been able to establish the decay from the known high-lying four-quasiparticle isomer, which we assign as a K=16 state at an excitation energy of Ex=2.928(3) MeV. The decay of this state passes through a rotational band based on a previously unobserved state at Ex=2.012(2) MeV, which we suggest is based on a two-quasineutron configuration with K=10. This state in turn decays to a rotational band based on the known K=8 isomer, which we infer must also have a two quasineutron configuration. We are able to assign many new gamma-rays associated with the decay of the K=8 isomer, including the identification of a highly K-forbidden ΔK=8 E1 transition to the ground-state band. These results provide valuable new information on the orbitals close to the Fermi surface, pairing correlations, deformation and rotational response, and K-conservation in nuclei of the deformed trans-fermium region.

  14. X-ray M-shell spectra of multiply-charged tungsten ions produced at the energy of the electron beam of 3.9 keV at the LLNL EBIT

    NASA Astrophysics Data System (ADS)

    Hoppe, Travis; Harris, Cliff; Beiersdorfer, Peter; Boyce, Kevin R.

    2005-05-01

    X-ray M-shell spectra of multiply-charged tungsten ions are spectroscopically studied. These spectra were collected at the LLNL EBIT-I at the energy of the electron beam of 3.9 keV and recorded by a broad-band x-ray microcalorimeter spectrometer (XRS). The XRS covered the spectral region from 3.5 to 8 å, which represented several distinct groups of lines due to 3-4, 3-5, and 3-6 transitions. The development of spectroscopic modeling of M-shell tungsten spectra is presented. Modeling indicates that Ni-like lines dominate at this electron energy and include not only the allowed E1 transitions but also the forbidden M1 and E2 transitions. The advantage of using LLNL EBIT data for the development of M-shell diagnostics of plasmas is shown. Work was supported by DOE-NNSA/NV Cooperative Agreement DE-FC52-01NV14050. Work at LLNL was performed under the auspices of the DOE by UC-LLNL under contract W-7405-Eng-48.

  15. Gamma-ray spectroscopy of the ^238U shape isomer.

    NASA Astrophysics Data System (ADS)

    Hauschild, K.; Bauer, R. W.; Becker, J. A.; Bernstein, L. A.; Britt, H. C.; Younes, W.; Fotiades, N.

    1997-04-01

    The γ--rays de--exciting the fission isomers ^236U and ^238U are very different despite similar excitation energies, lifetimes and low--lying yrast structures. The predominant γ--ray decay branch for ^236U^m is a 1.783 MeV E1 transition (J. Schirmer, et al., Phys. Rev. Lett. 63), 2196 (1989); and Refs. therein., while ^238U^m is depopulated by a 2.513 MeV E2 γ-ray (J. Kantele, et al., Phys. Rev. C 29), 1693 (1984); and Refs. therein.. Approximately 65% of the γ--branch de-exciting ^238U^m remains to be identified. To determine the multipolarity of the remaining γ-branch out of ^238U^m we used the Gammasphere array at LBNL and the ^238U(d,pn) reaction at Ed = 20 MeV. A search for excited states in the 2^nd well has also been conducted. Preliminary results will be presented, and the γ--decay of the shape isomers discussed in context with the recent A ~190 SD decay--out results (T. L. Khoo, et al., Phys. Rev. Lett. 76), 1583 (1996); A. Lopez-Martens, et al., Phys. Lett. B380, 18 (1996); K. Hauschild, et al., submitted to Phys. Rev. C (1996)..

  16. Octupole deformation in 144,146Ba measured by Coulomb excitation of radioactive beams

    NASA Astrophysics Data System (ADS)

    Bucher, Brian; Zhu, Shaofei; ANL, LBNL, LLNL, Rochester, Florida State, Liverpool, Maryland, Notre Dame, Ohio, W. Scotland Collaboration

    2015-10-01

    The exotic, neutron-rich 144Ba (t1 / 2 = 11.5 s) and 146Ba (t1 / 2 = 2.2 s) nuclei are expected to exhibit some of the strongest octupole correlations in A < 200 systems. Up to now, evidence for such strong octupole correlations has been inferred from observations of low-lying negative-parity states and from the interleaving of positive- and negative-parity levels in the ground-state band. However, the E1 transition strengths are very different in these two nuclei, with two orders of magnitude reduction in 146Ba. In this experiment, we measure the octupole strength directly by Coulomb excitation of post-accelerated 144,146Ba beams produced at CARIBU using CHICO2 and GRETINA. In 144Ba, we found B(E3;3 -->0) = 48(-34+ 25) W.u., a value considerably larger than theoretical predictions, while preliminary results for 146Ba are also indicative of strong octupole collectivity. The experimental conditions, the analysis, and the results from these challenging new measurements will be presented. This work is supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357 (ANL), DE-AC02-05CH11231 (LBNL, GRETINA), DOE DE-AC52-07NA27344 (LLNL), and NSF.

  17. Direct evidence of octupole deformation in neutron-rich 144Ba

    DOE PAGES

    Bucher, B.; Zhu, S.; Wu, C. Y.; Janssens, R. V. F.; Cline, D.; Hayes, A. B.; Albers, M.; Ayangeakaa, A. D.; Butler, P. A.; Campbell, C. M.; et al

    2016-03-17

    Here, the neutron-rich nucleus 144Ba (t1/2 = 11.5 s) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers A less than 200. Until now, indirect evidence for such strong correlations has been inferred from observations such as enhanced E1 transitions and interleaving positive- and negative-parity levels in the ground-state band. In this experiment, the octupole strength was measured directly by sub-barrier, multistep Coulomb excitation of a post-accelerated 650-MeV 144Ba beam on a 1.0–mg/cm2 208Pb target. The measured value of the matrix element, < 31–∥M(E3)∥01+ >= 0.65(+17–23) eb3/2, corresponds to a reduced B(E3) transition probabilitymore » of 48(+25–34) W.u. This result represents an unambiguous determination of the octupole collectivity, is larger than any available theoretical prediction, and is consistent with octupole deformation.« less

  18. Preparing the measurement of anapole moment in a chain of francium isotopes

    NASA Astrophysics Data System (ADS)

    Sheng, Dong

    This thesis presents the current status of the experimental efforts towards the measurement of the anapole moment in francium. The anapole moment is a parity violating, time-reversal conserving nuclear moment that arises from the weak interaction among nucleons. It is nuclear spin dependent and sensitive to the configuration of nuclear structure. Our experimental scheme is to perform a direct measurement of the anapole moment, by driving a parity forbidden E1 transition between ground hyperfine states in a series of francium isotopes inside a blue detuned dipole trap at the electric anti-node of a microwave cavity. We explore the tests using rubidium isotopes. The francium experiment will be moved to the ISAC radioactive beam facility of TRIUMF, Canada. During the preparation of the apparatus, we test the coherent control of the ground states via microwave and Raman beams, characterize the performance of a blue detuned dipole trap and study the atomic dynamics inside it using both classical and quantum methods. We also measure the lifetime of excited 5d states in Rb, with less than 1% uncertainty, to test and help to improve the current atomic structure theories.

  19. Study of the 3He(α,γ)7Be and 3H(α,γ)7Li reactions at astrophysical energies

    NASA Astrophysics Data System (ADS)

    Sadeghi, H.; Ghasemi, R.

    2014-06-01

    We have studied the important astrophysical 3He(α,γ)7Be and 3H(α,γ)7Li reactions in the framework of a potential model. 3He(α,γ)7Be and 3H(α,γ)7Li processes are key reactions in both bigbang nucleosynthesis and the p-p chain of hydrogen-burning in stars. The stellar 3He(α,γ)7Be and 3H(α,γ)7Li reactions were analyzed at low energies on the basis of a direct radiative capture mechanism. The astrophysical S-factors near zero energy were calculated without using the effective expansion of the S-factor or the asymptotic wave functions. In this paper, 3He(α,γ)7Be and 3H(α,γ)7Li radiative capture reactions at very low energies are taken as a case study. Using the M3Y potential, we have calculated the astrophysical S-factors for the E1 transition. In comparison with other theoretical methods and available experimental data, excellent agreement is achieved for the astrophysical S-factors of these processes.

  20. Two-quasiparticle isomer, E1 hindrances and residual interactions in {sup 172}Tm

    SciTech Connect

    Hughes, R. O.; Lane, G. J.; Dracoulis, G. D.; Kibedi, T.; Nieminen, P.; Watanabe, H.

    2008-04-15

    The structure of the neutron-rich nucleus {sup 172}Tm has been studied using incomplete fusion of {sup 7}Li on an {sup 170}Er target at 30 MeV. A 190-{mu}s isomer at an excitation energy of 476 keV was identified using chopped beams and {gamma}-ray spectroscopy. The isomer decays with very inhibited E1 transitions to the rotational bands based on the parallel and antiparallel couplings of the {nu}5/2{sup -}[512] x {pi}1/2{sup +}[411] configuration, the latter (K{sup {pi}}=2{sup -}) being the ground state. The isomeric state has been assigned J{sup {pi}}=6{sup +}, arising from the energetically favored (parallel) coupling of the {nu}5/2{sup -}[512] x {pi}7/2{sup -}[523] configuration. The proton-neutron residual interaction was deduced for the configuration of the isomeric state and is found to agree with previous empirical studies.

  1. A study of 75Se by neutron capture and the SU(3)-SU(5) transition in the quadrupole-phonon representation

    NASA Astrophysics Data System (ADS)

    Tokunaga, Y.; Seyfarth, H.; Schult, O. W. B.; Brant, S.; Paar, V.; Vretenar, D.; Borner, H. G.; Barreau, G.; Faust, H.; Hofmeyr, Ch.; Schreckenbach, K.; Meyer, R. A.

    1984-11-01

    The γ and e - spectra following thermal neutron capture in 74Se were studied with curved-crystal, β, and pair spectrometers. Precise energies have been obtained for the transitions and levels at low energies. Two primary E2 transitions were found. The neutron separation energy for 75Se was determined as 8027.6 keV. Precise γ-energies following the electron capture decay of 75Se were also measured, resulting in precise level energies in 75As. The calculation of the energy levels in 75Se has been performed in the SU(6) particle-vibrational model (PTQM) and 27 theoretical states have been tentatively assigned to the experimental levels. The spectrum of the core nucleus 74Se has been calculated in the SU(6) quadrupolephonon model (TQM). The structure of theoretical states, the relation to SU(3) and SU(5) limits, and potential energy surface are discussed. The E2, M1 and E1 transitions have been calculated in PTQM and compared to the experiment. Also, an overview is presented of theoretical explanations of the I = j, j-1, j-2 anomalous triplet emphasizing the rule with shell-model classification corrected for quadrupole phonons.

  2. QQ-onia package: a numerical solution to the Schrödinger radial equation for heavy quarkonium

    NASA Astrophysics Data System (ADS)

    Domenech-Garret, Juan-Luis; Sanchis-Lozano, Miguel-Angel

    2009-05-01

    This paper presents the basics of the QQ-onia package, a software based upon the Numerov O(h) method which can be used to solve the Schrödinger radial equation using a suitable potential V(r) for the heavy quarkonium system. This package also allows the analysis of relevant properties of those resonances such as the square of the wave functions at the origin, their corresponding derivatives for l≠0 states, typical heavy-quark velocities, and mean square radii. Besides, it includes a tool to analyze the spin dependent contributions to the heavy quarkonia spectrum, providing the splitting of nS-nS, as well as the nP-nP energy levels. Finally a simple software implemented in QQ-onia to compute E1 transition rates is presented. Program summaryProgram title: QQ-onia package Catalogue identifier: AECQ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AECQ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 17 706 No. of bytes in distributed program, including test data, etc.: 2 334 506 Distribution format: tar.gz Programming language: PAW, Physics Analysis Workstation ( http://wwwasd.web.cern.ch/wwwasd/paw/) Computer: PC/Workstation Operating system: Windows-XX and Unix (Linux) Classification: 11.1, 11.6 Nature of problem: Software to solve the Schrödinger radial equation using a suitable potential V(r) for the heavy quarkonium system, allowing to perform spectroscopy. It also allows the analysis of relevant quantities of those resonances such as the square of the wave functions at the origin, their corresponding derivatives for l≠0 states, typical heavy-quark velocities, and mean square radii. The package is a (userfriendly) multipurpose tool for dealing with different heavy quarkonium systems, providing a way to study the influence of a given potential on a

  3. Self-consistent quasiparticle formulation of a multiphonon method and its application to the neutron-rich O20 nucleus

    NASA Astrophysics Data System (ADS)

    De Gregorio, G.; Knapp, F.; Lo Iudice, N.; Vesely, P.

    2016-04-01

    A Bogoliubov quasiparticle formulation of an equation-of-motion phonon method, suited for open-shell nuclei, is derived. Like its particle-hole version, it consists of deriving a set of equations of motions whose iterative solution generates an orthonormal basis of n -phonon states (n =0 ,1 ,2 ,... ), built of quasiparticle Tamm-Dancoff phonons, which simplifies the solution of the eigenvalue problem. The method is applied to the open-shell neutron-rich O20 for illustrative purposes. A Hartree-Fock-Bogoliubov canonical basis, derived from an intrinsic two-body optimized chiral Hamiltonian, is used to derive and solve the eigenvalue equations in a space encompassing a truncated two-phonon basis. The spurious admixtures induced by the violation of the particle number and the center-of-mass motion are eliminated to a large extent by a Gram-Schmidt orthogonalization procedure. The calculation takes into account the Pauli principle, is self-consistent, and is parameter free except for the energy cutoff used to truncate the two-phonon basis, which induces an increasing depression of the ground state through its strong coupling to the quasiparticle vacuum. Such a cutoff is fixed so as to reproduce the first 1- level. The two-phonon states are shown to enhance the level density of the low-energy spectrum, consistently with the data, and to induce a fragmentation of the E 1 strength which, while accounting for the very low E 1 transitions, is not sufficient to reproduce the experimental cross section in the intermediate energy region. This and other discrepancies suggest the need of including the three-phonon states. These are also expected to offset the action of the two phonons on the quasiparticle vacuum and, therefore, free the calculation from any parameter.

  4. Transition rates for lithium-like ions, sodium-like ions, and neutral alkali-metal atoms

    SciTech Connect

    Johnson, W.R.; Liu, Z.W.; Sapirstein, J.

    1996-11-01

    Third-order many-body perturbation theory is used to obtain E1 transition amplitudes for ions of the lithium and sodium isoelectronic sequences and for the neutral alkali-metal atoms potassium, rubidium, cesium, and francium. Complete angular reductions of the first, second, and third-order amplitudes are given. Tables of transition energies and rates are given for the 2p{sub {1/2}} {yields} 2s{sub {1/2}}, 2p{sub 3/2} {yields} 2s{sub {1/2}}, 3s{sub {1/2}} {yields} 2p{sub {1/2}}, and 3s{sub {1/2}} {yields} 2p{sub 3/2} transitions in the lithium isoelectronic sequence and for the corresponding 3p{sub 1/2} {yields} 3s{sub 1/2}, 3p{sub 3/2} {yields} 3s{sub {1/2}}, 4s{sub {1/2}} {yields} 3p{sub 1/2}, and 4s{sub {1/2}} {yields} 3p{sub 3/2} transitions in the sodium sequence. For neutral alkali atoms, amplitudes of np{sub {1/2}} {yields} ns{sub {1/2}}, np{sub 3/2} {yields} ns{sub {1/2}}, (n + 1)s{sub {1/2}} {yields} np{sub {1/2}}, and (n + 1)s{sub {1/2}} {yields} np{sub 3/2} transitions are evaluated, where n is the principal quantum number of the valence electron in the atomic ground state, Semi-empirical corrections for the omitted fourth- and higher-order terms in perturbation theory are given for the neutral alkali-metal atoms. Comparisons with previous high-precision calculations and with experiment are made. 42 refs., 1 fig., 12 tabs.

  5. Mutational analysis of the conserved TGES loop of sarcoplasmic reticulum Ca2+-ATPase.

    PubMed

    Anthonisen, Anne Nyholm; Clausen, Johannes D; Andersen, Jens Peter

    2006-10-20

    Crystal structures have shown that the conserved TGES loop of the Ca2+-ATPase is isolated in the Ca2E1 state but becomes inserted in the catalytic site in E2 states. Here, we have examined the kinetics of the partial reaction steps of the transport cycle and the binding of the phosphoryl analogs BeF, AlF, MgF, and vanadate in mutants with alterations to the TGES residues. The mutations encompassed variation of size, polarity, and charge of the side chains. Differential effects on the Ca2E1P --> E2P, E2P --> E2, and E2 --> Ca2E1 reactions and the binding of the phosphoryl analogs were observed. In the E183D mutant, the E2P --> E2 dephosphorylation reaction proceeded at a rate as high as one-third that of the wild type, whereas it was very slow in the other Glu183 mutants, including E183Q, thus demonstrating the need for a negatively charged carboxylate group to catalyze dephosphorylation. By contrast, the Ca2E1P --> E2P transition was accomplished at a reasonable rate with glutamine in place of Glu183, but not with aspartate, indicating that the length of the Glu183 side chain, in addition to its hydrogen bonding potential, is critical for Ca2E1P --> E2P. This transition was also slowed in mutants with alteration to other TGES residues. The data provide functional evidence in support of the proposed role of Glu183 in activating the water molecule involved in the E2P --> E2 dephosphorylation and suggest a direct participation of the side chains of the TGES loop in the control and facilitation of the insertion of the loop in the catalytic site. The interactions of the TGES loop furthermore seem to facilitate its disengagement from the catalytic site during the E2 --> Ca2E1 transition. PMID:16893884

  6. Energy levels and radiative rates for transitions in Mg-like iron, cobalt and nickel

    SciTech Connect

    Aggarwal, K.M. . E-mail: k.aggarwal@qub.ac.uk; Tayal, Vikas; Gupta, G.P.; Keenan, F.P.

    2007-09-15

    Energy levels and radiative rates for electric dipole (E1) transitions among the lowest 141 levels of the (1s{sup 2}2s{sup 2}2p{sup 6}) 3l{sup 2}, 3l3l', and 3l4l configurations of Fe XV, Co XVI, and Ni XVII are calculated through the CIV3 code using extensive configuration-interaction (CI) wavefunctions. The important relativistic effects are included through the Breit-Pauli approximation. In order to keep the calculated energy splittings close to the experimental values, we have made small adjustments to the diagonal elements of the Hamiltonian matrices. The energy levels, including their orderings, are in excellent agreement with the available experimental results for all three ions. However, experimental energies are only available for a few levels. Since mixing among some levels is found to be very strong, it becomes difficult to identify these uniquely. Additionally, some discrepancies with other theoretical work (particularly for Ni XVII) are very large. Therefore, in order to confirm the level ordering as well as to assess the accuracy of energy levels and radiative rates, we have performed two other independent calculations using the GRASP and FAC codes. These codes are fully relativistic, but the CI in the calculations is limited to the basic (minimum) configurations only. This enables us to assess the importance of including elaborate CI for moderately charged ions. Additionally, we report results for electric quadrupole (E2), magnetic dipole (M1), and magnetic quadrupole (M2) transitions, and list lifetimes for all levels. Comparisons are made with other available experimental and theoretical results, and the accuracy of the present results is assessed.

  7. The Search for the Emission of a CP-Violating E1 Photon in the KL → π+π-γ Decay

    SciTech Connect

    Shields, John Michael

    2005-08-01

    A search for the CP-violating electric dipole (E1) direct emission contribution to the KL → π+π-γ decay is performed using data from the 1997 KTeV/E832 experiment. Because the KL → π+π-γ decay mode is massively dominated by the CP-violating inner bremsstrahlung (IB) and the CP-conserving magnetic dipole (M1) direct emission processes, previous analyses have neglected the E1 contribution. Therefore, this measurement is the first attempt to directly quantify the size of the E1 decay process. This E1 transition is one of the very few CP-violating processes that is accessible to experiment and, in principle, will produce new insights into the structure of the neutral kaon. The result of this analysis is that the E1 contribution is below the threshold of sensitivity, and therefore an upper bound of |gE1| < 0.14 (90% CL) is reported. In the process of obtaining this upper limit, high resolution measurements of fit parameters (~gM1 and a1/a2) associated with the size and shape of the M1 direct emission peak are also extracted. The fit results for these parameters: ~gM1 = 1.229 ± 0.035 (stat) ± 0.087 (syst); a1/a2 = -0.733 ± 0.007 (stat) ± 0.014 (syst) are in strong agreement with previous measurements.

  8. Development and evaluation of an instrument for rapid electroreflectance of semiconductor materials. Final technical report, 1 February 1988-30 April 1989

    SciTech Connect

    Herman, M.H.

    1989-06-30

    The applications of electron-beam electroreflectance (EBER) to Hg(1-x)Cd(x)Te (MCT) and other semiconductor systems are desired. Temperature dependences of the E1 optical gap of MCT are in agreement with the results of other researchers. For an epitaxial sample, alpha E (1)/alpha T of -(6.7 to 8.2) x .0001 eV/K was obtained. This value is consistent with that determined by Berlouis. The author finds a larger thermal coefficient for epitaxial MCT on CdTe than for bulk MCT. He also measured the E(1) Delta (1) band gap to be nearly 0.63 eV above the E1 transition energy. MCT is more sensitive to electron beam current intensity than other materials due to its relatively poor thermal conductivity. The line shape observed at .001 A/sq.cm appears to be from thermoreflectance (TR), based upon calculations and detailed experimental studies. Therefore, EBER determinations of the temperature dependence of the E1 and E1+Delta (1) band gap energies demonstrate a large variance. The author has collaborated with other researchers on EBER evaluation of MCT growth and dry-etch processes. He has extended EBER studies to other technologically important crystal systems related to MCT. Correlations were found between the EBER measurements of CdTe samples and surface-preparation methods. In the case of GaAs and related compounds, results show promise in the analysis of epitaxial films and heterostructures, which are briefly described.

  9. Spectroscopic second-harmonic generation during Ar+ -ion bombardment of Si(100)

    NASA Astrophysics Data System (ADS)

    Gielis, J. J. H.; Gevers, P. M.; Stevens, A. A. E.; Beijerinck, H. C. W.; van de Sanden, M. C. M.; Kessels, W. M. M.

    2006-10-01

    Spectroscopic and real time optical second-harmonic generation (SHG) has been applied to gain insight into the surface and interface processes during low-energy (70-1000eV) Ar+ -ion bombardment of H terminated Si(100). The Ar+ -ion bombardment of the crystalline silicon (c-Si) , which creates a layer of amorphous silicon (a-Si) , has been studied in the SH photon energy range of 2.7-3.5eV . The time-resolved SHG signal has been observed to increase with an order of magnitude upon ion bombardment. Spectroscopic SHG during ion bombardment and after subsequent XeF2 dosing indicates that the SHG signal has both a contribution generated at the buried interface between the a-Si and the c-Si and an additional contribution originating from the a-Si surface. By separating these contributions using a critical point model it has been shown that the SHG spectra consist of a sharp resonance at 3.36eV with a linewidth of 0.1eV at the buried a-Si/c-Si interface and a much broader resonance at a resonance energy of 3.2eV with a linewidth of 0.5eV at the a-Si surface. The former resonance is identified to originate from E0'/E1 transitions between bulk electronic states in the c-Si that are modified due to the vicinity of the interface, while the latter resonance is caused by transitions related to Si-Si bonds in the surface region of the a-Si . The time-resolved dynamics of the SHG signal can help in understanding the mechanism of ion-beam and plasma etching of silicon.

  10. Electric-dipole allowed and intercombination transitions among the 3d{sup 5}, 3d{sup 4}4s and 3d{sup 4}4p levels of Fe IV

    SciTech Connect

    Deb, Narayan C.; Hibbert, Alan

    2010-07-15

    Oscillator strengths and transition rates for the electric-dipole (E1) allowed and intercombination transitions among 3d{sup 5}, 3d{sup 4}4s and 3d{sup 4}4p levels of Fe IV are calculated using the CIV3 code of Hibbert and coworkers. Using the Hartree-Fock functions up to 3d orbitals we have also optimized 4s, 4p, 4d, 4f, 5s, 5p and 5d orbitals of which 4s and 4p are taken to be spectroscopic and the remaining orbitals represent corrections to the spectroscopic orbitals or the correlation effects. The J-dependent levels of 108 LS states are included in the calculation and the relativistic effects are accounted for via the Breit-Pauli operator. Configurations are chosen in two steps: (a) two promotions were allowed from the 3p, 3d, 4s and 4p subshells, using all the orbitals; and (b) selective promotions from the 3s subshell are included, but only to the 3s and 4s orbitals. The ab initio fine-structure levels are then fine tuned to reproduce observed energy levels as closely as possible, and the resulting wavefunctions are used to calculate oscillator strengths and transition rates for all possible E1 transitions. For many of these transitions, the present results show good agreement between the length and velocity forms while for some transitions, some large disagreements are found with other available results. The complete list of weighted oscillator strengths, transition rates, and line strengths for transitions among the fine structure levels of the three lowest configurations are presented in ascending order of wavelength.

  11. Study of the neutron and proton capture reactions 10,11B(n, γ), 11B(p, γ), 14C(p, γ), and 15N(p, γ) at thermal and astrophysical energies

    NASA Astrophysics Data System (ADS)

    Dubovichenko, Sergey; Dzhazairov-Kakhramanov, Albert

    2014-07-01

    We have studied the neutron-capture reactions 10,11B(n, γ) and the role of the 11B(n, γ) reaction in seeding r-process nucleosynthesis. The possibility of the description of the available experimental data for cross-sections of the neutron capture reaction on 10B at thermal and astrophysical energies, taking into account the resonance at 475 keV, was considered within the framework of the modified potential cluster model (MPCM) with forbidden states (FS) and accounting for the resonance behavior of the scattering phase shifts. In the framework of the same model, the possibility of describing the available experimental data for the total cross-sections of the neutron radiative capture on 11B at thermal and astrophysical energies were considered with taking into account the 21 and 430 keV resonances. Description of the available experimental data on the total cross-sections and astrophysical S-factor of the radiative proton capture on 11B to the GS of 12C was treated at astrophysical energies. The possibility of description of the experimental data for the astrophysical S-factor of the radiative proton capture on 14C to the GS of 15N at astrophysical energies, and the radiative proton capture on 15N at the energies from 50 to 1500 keV was considered in the framework of the MPCM with the classification of the orbital states according to Young tableaux. It was shown that, on the basis of the M1 and the E1 transitions from different states of the p15N scattering to the GS of 16O in the p15N channel, it is quite succeed to explain general behavior of the S-factor in the considered energy range in the presence of two resonances.

  12. High-Resolution {alpha} and Electron Spectroscopy of {sup 249}{sub 98}Cf

    SciTech Connect

    Ahmad, I.; Greene, J. P.; Kondev, F. G.; Zhu, S.

    2015-04-13

    alpha-particle spectra of Cf-249 have been measured with a double-focusing magnetic spectrometer and with passivated implanted planar silicon (PIPS) detectors. The conversion-electron spectra of Cf-249 have been measured with a cooled Si(Li) detector and with a room-temperature PIPS detector. Precise energies of a groups in the decay of Cf-249 have been measured with respect to the known energy of Cf-250. In addition, alpha-electron, alpha-gamma, and gamma-gamma coincidence measurements were also performed to determine the spin-parity of the previously known 643.64-keV level. From electron intensities, conversion coefficients of transitions in the daughter Cm-245 have been determined. The measured L-3 conversion coefficients of the 333.4- and 388.2-keV transitions are found to be in agreement with the theoretical conversion coefficients for pure E1 multipolarity. On the other hand, the K, L-1 + L-2, M, and N conversion coefficients are approximately twice the theoretical values for pure E1 transitions. These measurements indicate anomalous E1 conversion coefficients for the 333.4- and 388.2-keV transitions, as has been pointed out in earlier measurements. The measured conversion coefficient of the 255.5-keV transition gives an M1 multipolarity for this transition which establishes a spin-parity of 7/2(-) and the 7/2(-)[743] single-particle assignment to the 643.64-keV level.

  13. Atomic Structure and Fundamental Symmetry Measurements in a Thallium Atomic Beam

    NASA Astrophysics Data System (ADS)

    Majumder, P. K.; Nicholas, P. C.

    1998-05-01

    We have completed construction and testing of a new high-flux thallium atomic beam apparatus. Using a multiple slit oven source we achieve a favorable combination of throughput and modest Doppler narrowing. An in-vacuum chopper wheel provides ≈ 100 Hz modulation of the atomic beam and allows lock-in detection in the case of weak atomic beam absorption. Electric field plates allow precise application of ± 30 kV/cm fields in the interaction region. We will describe ongoing atomic beam spectroscopy of the 378 nm E1 transition, and a planned measurement of the Stark-induced amplitudes within the thallium 6P_1/2 - 6P_3/2 1283 nm M1 transition. We will also present the details of a new experimental proposal to search for time reversal-violating (T-odd, P-even) forces in thallium. In this new scheme, the 1283 nm M1 laser, tuned near the F=0arrowF'=1 transition, would be directed into high-finesse cavity which incorporates the atomic beam. In the presence of a longitudinal static electric field, E, a `TOPE' signature is revealed here by a cavity phase shift proportional to (hatk\\cdotE). We would search for a differential phase shift of counterpropagating (± hatk) laser beams correlated to electric field reversal. The cavity finesse both amplifies any TOPE effect and increases the precision with which it can be detected, while the differencing technique greatly reduces sensitivity to laser frequency or mechanical fluctuations.

  14. Decay of a {pi}h{sub 11/2} x {nu}h{sub 11/2} microsecond isomer in {sub 61}{sup 136}Pm{sub 75}

    SciTech Connect

    Rigby, S. V.; Cullen, D. M.; Mason, P. J. R.; Scholes, D. T.; Scholey, C.; Rahkila, P.; Eeckhaudt, S.; Grahn, T.; Greenlees, P.; Jones, P. M.; Julin, R.; Juutinen, S.; Kettunen, H.; Leino, M.; Leppaenen, A.-P.; Nieminen, P.; Nyman, M.; Pakarinen, J.; Uusitalo, J.

    2008-09-15

    An experiment has been performed to populate several extremely neutron-deficient nuclei around the mass-140 region of the nuclear chart, using a beam of {sup 54}Fe on a {sup 92}Mo target at an energy of 315 MeV. Analysis of these data using recoil-isomer tagging has established that the yrast {pi}h{sub 11/2} x {nu}h{sub 11/2},J{sup {pi}}=(8{sup +}), bandhead state in {sup 136}Pm is isomeric with a half-life of 1.5(1) {mu}s. This isomeric state decays via a 43-keV, probable-E1 transition to a J{sup {pi}}=(7{sup -}) state. Consideration of the theoretical Nilsson orbitals near the Fermi surface suggests that the J{sup {pi}}=(8{sup +}) state has a {nu}h{sub 11/2}[505](11/2){sup -} x {pi}h{sub 11/2}[532](5/2){sup -} configuration, which decays to the J{sup {pi}}=(7{sup -}) state with a {nu}h{sub 11/2}[505](11/2){sup -} x {pi}d{sub 5/2}[411](3/2){sup +} configuration. Differences in the shape-driving effects for these two configurations is reasoned to be responsible for the long half-life of the J{sup {pi}}=(8{sup +}) isomeric state. The non-observation of other {gamma} rays in prompt or delayed coincidence with the 43-keV transition suggests that this transition may feed another, longer lived isomeric state with a half-life of the order of milliseconds or greater. However, the present experiment was not sensitive to the decay of this new J{sup {pi}}=(7{sup -}) state by internal conversion or even {beta} decay.

  15. Relativistic many-body calculations of excitation energies and transition rates from core-excited states in copperlike ions

    NASA Astrophysics Data System (ADS)

    Safronova, U. I.; Johnson, W. R.; Shlyaptseva, A.; Hamasha, S.

    2003-05-01

    Energies of (3s23p63d94l4l'), (3s23p53d104l4l'), and (3s3p63d104l4l') states for Cu-like ions with Z=30 100 are evaluated to second order in relativistic many-body perturbation theory (RMBPT) starting from a Ni-like Dirac-Fock potential. Second-order Coulomb and Breit-Coulomb interactions are included. Correction for the frequency dependence of the Breit interaction is taken into account in lowest order. The Lamb shift correction to energies is also included in lowest order. Intrinsic particle-particle-hole contributions to energies are found to be 20 30 % of the sum of one- and two-body contributions. Transition rates and line strengths are calculated for the 3l-4l' electric-dipole (E1) transitions in Cu-like ions with nuclear charge Z=30 100. RMBPT including the Breit interaction is used to evaluate retarded E1 matrix elements in length and velocity forms. First-order RMBPT is used to obtain intermediate coupling coefficients, and second-order RMBPT is used to calculate transition matrix elements. A detailed discussion of the various contributions to the dipole- matrix elements and energy levels is given for copperlike tungsten (Z=74). The transition energies used in the calculation of oscillator strengths and transition rates are from second-order RMBPT. Trends of the transition rates as functions of Z are illustrated graphically for selected transitions. Comparisons are made with available experimental data. These atomic data are important in the modeling of M-shell radiation spectra of heavy ions generated in electron-beam ion trap experiments and in M-shell diagnostics of plasmas.

  16. High-resolution α and electron spectroscopy of Cf24998

    NASA Astrophysics Data System (ADS)

    Ahmad, I.; Greene, J. P.; Kondev, F. G.; Zhu, S.

    2015-04-01

    α -particle spectra of 249Cf have been measured with a double-focusing magnetic spectrometer and with passivated implanted planar silicon (PIPS) detectors. The conversion-electron spectra of 249Cf have been measured with a cooled Si(Li) detector and with a room-temperature PIPS detector. Precise energies of α groups in the decay of 249Cf have been measured with respect to the known energy of 250Cf. In addition, α -electron, α -γ , and γ -γ coincidence measurements were also performed to determine the spin-parity of the previously known 643.64-keV level. From electron intensities, conversion coefficients of transitions in the daughter 245Cm have been determined. The measured L3 conversion coefficients of the 333.4- and 388.2-keV transitions are found to be in agreement with the theoretical conversion coefficients for pure E 1 multipolarity. On the other hand, the K ,L1+L2 ,M , and N conversion coefficients are approximately twice the theoretical values for pure E 1 transitions. These measurements indicate anomalous E 1 conversion coefficients for the 333.4- and 388.2-keV transitions, as has been pointed out in earlier measurements. The measured conversion coefficient of the 255.5-keV transition gives an M 1 multipolarity for this transition which establishes a spin-parity of 7/2- and the 7/2-[743 ] single-particle assignment to the 643.64-keV level.

  17. NUSTART: A PC code for NUclear STructure And Radiative Transition analysis and supplementation

    SciTech Connect

    Larsen, G.L.; Gardner, D.G.; Gardner, M.A.

    1990-10-01

    NUSTART is a computer program for the IBM PC/At. It is designed for use with the nuclear reaction cross-section code STAPLUS, which is a STAPRE-based CRAY computer code that is being developed at Lawrence Livermore National Laboratory. The NUSTART code was developed to handle large sets of discrete nuclear levels and the multipole transitions among these levels; it operates in three modes. The Data File Error Analysis mode analyzes an existing STAPLUS input file containing the levels and their multipole transition branches for a number of physics and/or typographical errors. The Interactive Data File Generation mode allows the user to create input files of discrete levels and their branching fractions in the format required by STAPLUS, even though the user enters the information in the (different) format used by many people in the nuclear structure field. In the Branching Fractions Calculations mode, the discrete nuclear level set is read, and the multipole transitions among the levels are computed under one of two possible assumptions: (1) the levels have no collective character, or (2) the levels are all rotational band heads. Only E1, M1, and E2 transitions are considered, and the respective strength functions may be constants or, in the case of E1 transitions, the strength function may be energy dependent. The first option is used for nuclei closed shells; the bandhead option may be used to vary the E1, M1, and E2 strengths for interband transitions. K-quantum number selection rules may be invoked if desired. 19 refs.

  18. New isomers and medium-spin structure of the {sup 95}Y nucleus

    SciTech Connect

    Urban, W.; Sieja, K.; Simpson, G. S.; Rzaca-Urban, T.; Zlomaniec, A.; Lukasiewicz, M.; Smith, A. G.; Durell, J. L.; Smith, J. F.; Varley, B. J.; Nowacki, F.; Ahmad, I.

    2009-04-15

    Excited states in {sup 95}Y, populated following the spontaneous fission of {sup 248}Cm and {sup 252}Cf and following fission of {sup 235}U induced by thermal neutrons, were studied by means of {gamma} spectroscopy using the EUROGAM2 and GAMMASPHERE multidetector Ge arrays and the LOHENGRIN fission-fragment separator, respectively. We have found a new (17/2{sup -}) isomer in {sup 95}Y at 3142.2 keV with a half-life of T{sub 1/2}=14.9(5) ns. Another isomer was identified in {sup 95}Y at 5022.1 keV and it was assigned a spin-parity (27/2{sup -}). For this isomer a half-life of T{sub 1/2}=65(4) ns was determined and four decay branches were found, including an E3 decay. A new E3 decay branch was also found for the known, 1087.5-keV isomer in {sup 95}Y, for which we measured a half-life of 51.2(9) {mu}s. The B(E3) and B(E1) transition rates, of 2.0 and 3.8x10{sup -7} W.u., respectively, observed in {sup 95}Y are significantly lower than in the neighboring {sup 96}Zr core, suggesting that octupole correlations in this region are mainly due to the coupling of proton {delta}j=3 orbitals. Shell-model calculations indicate that the (27/2{sup -}) isomer in {sup 95}Y corresponds to the {pi}g{sub 9/2}{nu}(g{sub 7/2}h{sub 11/2}) maximally aligned configuration and that all three isomers in {sup 95}Y decay, primarily, by M2 transitions between proton g{sub 9/2} and f{sub 5/2} orbitals.

  19. Multiple band structures of {sup 131}Cs

    SciTech Connect

    Sihotra, S.; Palit, R.; Naik, Z.; Joshi, P. K.; Deo, A. Y.; Jain, H. C.; Singh, K.; Goswamy, J.; Mehta, D.; Singh, N.; Malik, S. S.; Praharaj, C. R.

    2008-09-15

    Excited states in {sup 131}Cs were investigated through in-beam {gamma}-ray spectroscopic techniques following its population in the {sup 124}Sn({sup 11}B, 4n) fusion-evaporation reaction at a beam energy of 46 MeV. The previously known level scheme has been substantially extended up to {approx}9 MeV excitation energy and 49/2({Dirac_h}/2{pi}) spin with the addition of seven new band structures. The present level scheme consisting of 15 bands exhibits a variety of collective features in this nucleus at intermediate spin. The excitation energies of the observed levels in different bands and the corresponding ratios of transition strengths, i.e., B(M1)/B(E2), have been compared with the results of projected deformed Hartree-Fock calculations based on various quasiparticle configurations. A strongly coupled band has been reassigned a high-K three-quasiparticle {pi}h{sub 11/2} x {nu}(h{sub 11/2}d{sub 3/2}) configuration based on the properties of this band and that of its new coupled side band. The configurations of these bands are also discussed in the framework of tilted-axis cranking model calculations and the systematics of the odd-A Cs isotopes. Additional three energetically closely placed coupled bands have been assigned different unpaired three-quasiparticle configurations. {gamma}-vibrational bands coupled to the {pi}h{sub 11/2} and {pi}g{sub 7/2} single-particle configurations have been reported in this nucleus. Observation of new E1 transitions linking the opposite-parity {pi}h{sub 11/2} and {pi}d{sub 5/2} bands provides fingerprints of possible octupole correlations.

  20. Nuclear structure studies close to N = Z = 50

    SciTech Connect

    Kumar, S.; Sihotra, S.; Singh, K.; Goswami, J.; Singh, N.; Mehta, D.; Naik, Z.; Palit, R.; Muralithar, S.; Kumar, R.; Singh, R. P.; Bhowmik, R. K.

    2014-08-14

    The level structures in {sup 98,99}Rh, and {sup 99}Pd nuclei have been investigated through in beam γ-ray spectroscopic techniques following the {sup 75}As({sup 28}Si, xpyn) fusion-evaporation reaction at E{sub lab} = 120 MeV. These investigations were carried out using Indian-National-Gamma-Array (INGA) consisting of Compton-suppressed clover detectors at the Inter-University Accelerator Centre, New Delhi. The level structures observed in {sup 99}Pd, and {sup 98,99}Rh have been established up to ∼ 11 MeV, 10 MeV and 16 MeV excitation energy and spin ∼ 23ħ, 23ħ, and 28ħ respectively. In the doubly-odd {sup 98}Rh nucleus, new band structures and isomeric states have been identified at lower spins and new states below the previously identified 2{sup +} ground state (T{sub 1/2} = 8.5 m) are identified. In the present work {sup 99}Rh structure have been observed similar to {sup 101}Rh which is based on p{sub 1/2} and g{sub 9/2} orbitals. Various positive and negative parity states in these nuclei are observed to be energetically more favored with respect to the neighboring ones, and are likely to be the maximally aligned states obtained by angular momentum coupling of the valence particles (holes). The level structures observed in {sup 99}Pd have been interpreted in the framework of a microscopic theory based on the deformed Hartree-Fock (HF) and angular momentum projection techniques. Band structures at low excitation energy are based on the low-Ω νg{sub 7/2} and νd{sub 5/2} orbitals, have been observed in {sup 99}Pd. Band structure at higher spins are reproduced with the ν(g{sub 7/2}){sup 2}⊗ν(g{sub 9/2}){sup −1}⊗ν(h{sub 11/2}){sup 2}⊗π(g{sub 9/2}){sup 6} configurations. Observation of new E1 transitions linking the opposite parity νh{sub 11/2} and νd{sub 5/2} bands provide fingerprints of possible octupole correlations in {sup 99}Pd. The extracted values of the B(E1)/B(E2) ratios for the lower levels in the νh{sub 11/2} band are ∼ 10{sup

  1. Nuclear structure studies close to N = Z = 50

    NASA Astrophysics Data System (ADS)

    Kumar, S.; Sihotra, S.; Naik, Z.; Singh, K.; Goswami, J.; Singh, N.; Palit, R.; Muralithar, S.; Kumar, R.; Singh, R. P.; Bhowmik, R. K.; Mehta, D.

    2014-08-01

    The level structures in 98,99Rh, and 99Pd nuclei have been investigated through in beam γ-ray spectroscopic techniques following the 75As(overflow="scroll">28Si, xpyn) fusion-evaporation reaction at Elab = 120 MeV. These investigations were carried out using Indian-National-Gamma-Array (INGA) consisting of Compton-suppressed clover detectors at the Inter-University Accelerator Centre, New Delhi. The level structures observed in 99Pd, and 98,99Rh have been established up to ˜ 11 MeV, 10 MeV and 16 MeV excitation energy and spin ˜ 23ħ, 23ħ, and 28ħ respectively. In the doubly-odd 98Rh nucleus, new band structures and isomeric states have been identified at lower spins and new states below the previously identified 2+ ground state (T1/2 = 8.5 m) are identified. In the present work 99Rh structure have been observed similar to 101Rh which is based on p1/2 and g9/2 orbitals. Various positive and negative parity states in these nuclei are observed to be energetically more favored with respect to the neighboring ones, and are likely to be the maximally aligned states obtained by angular momentum coupling of the valence particles (holes). The level structures observed in 99Pd have been interpreted in the framework of a microscopic theory based on the deformed Hartree-Fock (HF) and angular momentum projection techniques. Band structures at low excitation energy are based on the low-Ω νg7/2 and νd5/2 orbitals, have been observed in 99Pd. Band structure at higher spins are reproduced with the ν(g7/2)2⊗ν(g9/2)-1⊗ν(h11/2)2⊗π(g9/2)6 configurations. Observation of new E1 transitions linking the opposite parity νh11/2 and νd5/2 bands provide fingerprints of possible octupole correlations in 99Pd. The extracted values of the B(E1)/B(E2) ratios for the lower levels in the νh11/2 band are ˜ 10-7 [fm]-2.

  2. Relativistic many-body calculations of electric-dipole lifetimes, rates, and oscillator strengths of Delta(n) = 0 transitions between 3l^-1 4l' states in Ni-like ions

    SciTech Connect

    Safronova, U I; Safronova, A S; Beiersdorfer, P

    2007-01-05

    Transition rates, oscillator strengths, and line strengths are calculated for electric-dipole (E1) transitions between odd-parity 3s{sup 2}3p{sup 6}3d{sup 9}4{ell}{sub 2}, 3s{sup 2}3p{sup 5}3d{sup 10}4{ell}{sub 2}, and 3s3p{sup 6}3d{sup 10}4{ell}{sub 1} states and even-parity 3s{sup 2}3p{sup 6}3d{sup 9}4{ell}{sub 2}, 3s{sup 2}3p{sup 5}3d{sup 10}4{ell}{sub 1}, and 3s3p{sup 6}3d{sup 10}4{ell}{sub 2} (with 4{ell}{sub 1} = 4p; 4f and 4{ell}{sub 2} = 4s; 4d) in Ni-like ions with the nuclear charges ranging from Z = 34 to 100. Relativistic many-body perturbation theory (RMBPT), including the Breit interaction, is used to evaluate retarded E1 matrix elements in length and velocity forms. The calculations start from a 1s{sup 2}2s{sup 2}2p{sup 6}3s{sup 2}3p{sup 6}3d{sup 10} Dirac-Fock potential. First-order RMBPT is used to obtain intermediate coupling coefficients and second-order RMBPT is used to calculate transition matrix elements. Contributions from negative-energy states are included in the second-order E1 matrix elements to ensure the gauge independence of transition amplitudes. Transition energies used in the calculation of oscillator strengths and transition rates are from second-order RMBPT. Lifetimes of the 3s{sup 2}3p{sup 6}3d{sup 9}4d levels are given for Z = 34-100. Transition rates, line strengths, and oscillator strengths are compared with critically evaluated experimental values and with results from other recent calculations. These atomic data are important in modeling of M-shell radiation spectra of heavy ions generated in electron beam ion trap experiments and in M-shell diagnostics of plasmas.

  3. Radiative capture of polarized deuterons by [sup 6]Li and the D-state of [sup 8]Be

    SciTech Connect

    Williams, J.Z. Jr.

    1992-01-01

    Measurements of angular distributions of the cross section, [sigma]([theta]), and vector and tensor analyzing powers have been obtained at E[sub d] (lab) = 9.0 MeV and E[sub d] (lab) = 2.0 MeV for the [sup 6]Li([rvec d],[gamma])[sup 8]Be reaction. The measured analyzing powers include A[sub yy]([theta]) and A[sub y]([theta]) at E[sub d] (lab) = 2.0 MeV and A[sub yy] ([theta]), A[sub y] ([theta]) and T[sub 20]([theta]) at E[sub d] (lab) = 9.0 MeV. Energy excitation functions of the differential cross section, [sigma]([theta]) at [theta] = 130[degrees] were measured from E[sub d] (lab) = 7.0 MeV to E[sub d] (lab) = 14.0 MeV. Transition matrix element analyses of the angular distributions at E[sub d] (lab) = 9.0 MeV and E[sub d] (lab) = 2.0 MeV were performed. The results show the presence of 13% to 21% E1 radiation in addition to the dominant E2 radiation at E[sub d] (lab) = 9.0 MeV and a dominant E1 radiation contribution, instead of dominant E2 radiation, of 57% at E[sub d] (lab) = 2.0 MeV. The largest E1 component at both energies is the isospin forbidden E1 transition comprising 10% of the cross section at E[sub d] (lab) = 9.0 MeV and 40% of the cross section at E[sub d] (lab) = 2.0 MeV. The angular distributions at E[sub d] (lab) = 9.0 MeV were compared to a simple direct capture (DC) calculation. The dominant E2 direct capture calculation gave a reasonable description of the tensor analyzing power A[sub yy] ([theta]) but failed to reproduce the cross section [sigma]([theta]) and the vector analyzing power A[sub y]([theta]). This model leads to a D-state probability of P[sub D] = 0.5% for the ground state of [sup 8]Be. A multichannel resonating group model (MCRGM) calculation was also performed. This calculation provided a fairly good representation of the data and predicts a D-state probability of P[sub D] = 0.3% for the ground state of [sup 8]Be.

  4. Theoretical study on the low-lying excited states of the phosphorus monoiodide (PI) including the spin-orbit coupling

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaomei; Liu, Xiaoting; Liang, Guiying; Li, Rui; Xu, Haifeng; Yan, Bing

    2016-01-01

    The potential energy curves (PECs) of the 22 Λ-S states of the phosphorus monoiodide (PI) molecule have been calculated at the level of MRCI+Q method with correlation-consistent quadruple-ζ quality basis set. The spectroscopic constants of the bound states are determined, which well reproduce the available measurements. The metastable a1Δ state has been reported for the first time, which lies between the X3Σ- and b1Σ+ states and have much deeper well than the ground state. The R-dependent spin-orbit (SO) matrix elements are calculated with the full-electron Breit-Pauli operator. Based on the SO matrix elements, the perturbations that the 23Π state may suffer from are analyzed in detail. The SOC effect makes the original Λ-S states split into 51 Ω states. In the zero-field splitting of the ground state X3Σ-, the spin-spin coupling contribution (2.23 cm-1) is found to be much smaller compared to the spin-orbit coupling contribution (50 cm-1). The avoided crossings between the Ω states lead to much shallower potential wells and the change of dissociation relationships of the states. The Ω-state wavefunctions are analyzed depending on their Λ-S compositions, showing the strong interactions among several quasidegenerate Λ-S states of the same total SO symmetry. The transition properties including electric dipole (E1), magnetic dipole (M1), and electric quadrupole (E2) transition moments (TMs), the Franck-Condon factors, the transition probabilities and the radiative lifetimes are computed for the transitions between Ω components of a1Δ and b1Σ+ states and ground state. The transition probabilities induced by the E1, E2, and M1 transitions are evaluated. The E2 makes little effect on transition probabilities. In contrast, the E1 transition makes the main contribution to the transition probability and the M1 transition also brings the influence that cannot be neglected. Finally, the radiative lifetimes are determined with the transition moments including E

  5. Thermal neutron capture gamma rays from sulfur isotopes: Experiment and theory

    NASA Astrophysics Data System (ADS)

    Raman, S.; Carlton, R. F.; Wells, J. C.; Jurney, E. T.; Lynn, J. E.

    1985-07-01

    We have carried out a systematic investigation of γ rays after thermal neutron capture by all stable sulfur isotopes (32S, 33S, 34S, and 36S). The measurements were made at the internal target facility at the Los Alamos Omega West Reactor. We detected a larger number of γ rays: ~100 in 33S, ~270 in 34S, ~60 in 35S, and ~15 in 37S. Before developing detailed level schemes, we culled and then consolidated the existing information on energies and Jπ values for levels of these nuclides. Based on the current data, we have constructed detailed decay schemes, which imply that there are significant populations of 26 excited states in 33S, 70 states in 34S, 20 states in 35S, and 7 states in 37S. By checking the intensity balance for these levels and by comparing the total intensity of primary transitions with the total intensity of secondary γ rays feeding the ground state, we have demonstrated the relative completeness of these decay schemes. For strongly populated levels, the branching ratios based on the current measurements are generally better than those available from previous measurements. In all four cases, a few primary electric dipole (E1) transitions account for a large fraction of the capture cross section for that particular nuclide. To understand and explain these transitions, we have recapitulated and further developed the theory of potential capture. Toward this end, we reviewed the theory relating off-resonance neutron capture to the optical-model capture. We studied a range of model-dependent effects (nature and magnitude of imaginary potential, surface diffuseness, etc.) on the potential capture cross section, and we have shown how experimental data may be analyzed using the expression for channel capture suitably modified by a factor that takes into account the model-dependent effects. The calculations of cross sections for most of the primary transitions in the sulfur isotopes are in good agreement with the data. Some discrepancies for weaker

  6. Information Content of the Low-Energy Electric Dipole Strength: Correlation Analysis

    SciTech Connect

    Reinhard, P.-G.; Nazarewicz, Witold

    2013-01-01

    Background: Recent experiments on the electric dipole (E1) polarizability in heavy nuclei have stimulated theoretical interest in the low-energy electric dipole strength, both isovector and isoscalar. Purpose: We study the information content carried by the electric dipole strength with respect to isovector and isoscalar indicators characterizing bulk nuclear matter and finite nuclei. To separate isoscalar and isovector modes, and low-energy strength and giant resonances, we analyze the E1 strength as a function of the excitation energy E and momentum transfer q. Methods: We use the self-consistent nuclear density functional theory with Skyrme energy density functionals, augmented by the random phase approximation, to compute the E1 strength and covariance analysis to assess correlations between observables. Calculations are performed for the spherical, doubly magic nuclei 208Pb and 132Sn. Results: We demonstrate that E1 transition densities in the low-energy region below the giant dipole resonance exhibit appreciable state dependence and multinodal structures, which are fingerprints of weak collectivity. The correlation between the accumulated low-energy strength and the symmetry energy is weak, and dramatically depends on the energy cutoff assumed. On the other hand, a strong correlation is predicted between isovector indicators and the accumulated isovector strength at E around 20 MeV and momentum transfer q 0.65 fm 1. Conclusions: Momentum- and coordinate-space patterns of the low-energy dipole modes indicate a strong fragmentation into individual particle-hole excitations. The global measure of low-energy dipole strength correlates poorly with the nuclear symmetry energy and other isovector characteristics. Consequently, our results do not support the suggestion that there exists a collective pygmy dipole resonance, which is a strong indicator of nuclear isovector properties. By considering nonzero values of momentum transfer, one can isolate individual

  7. Studies of Octupole Structures in RADON-220,222 and RADIUM-224.

    NASA Astrophysics Data System (ADS)

    Poynter, Raymond John

    Available from UMI in association with The British Library. alpha-gamma angular correlation measurements have been made using the alpha-radioactive sources ^{226}Ra and ^{228}Th in the POLYTESSA array at the N.S.F., Daresbury Laboratory. These measurements enabled spin-parity (J^{pi}) assignments to be made to nuclei in the two decay chains. The J^{pi} assignments have been made as follows; 1^ {-} and 3^{-} to the 601 and 635keV levels (respectively) in ^{222}Rn, 1^ {-} to the 645 keV level in ^ {220}Rn, 2^{+} to the 510 and 550keV levels (the first excited states) in ^{218,216}Po respectively, 4^{+} to the 250keV level in ^{224}Ra and 4^{+} to the 448 and 534 levels in ^{222,220}Rn respectively. alpha-e^ {-} coincidence measurements with the ^{228}Th source in the superconducting electron solenoid spectrometer also at the N.S.F. have been performed and the internal conversion coefficient for the 205keV transition in ^ {224}Ra has been measured. The 205keV transition was demonstrated to be an E1 transition, thus the 292keV level is assigned as having J^ {pi}=3^{-} (or 1^{-}). These J ^{pi} assignments have enabled interpretation of alpha hindrance factors to the low-lying negative parity levels in these radium and radon nuclei. The systematics of alpha hindrance factors in these nuclei are compared with others from the region. A preliminary experiment on the higher spin structure of ^{224}Ra has been performed utilising the ^{226}Ra (^{58}Ni,^ {60}Ni)^{224} Ra^{*} reaction, also on the POLYTESSA array. The use of a transfer reaction necessitated the event-by-event correction of the Doppler shift of the gamma-rays. The experimental apparatus used to enable this correction is described. gamma-gamma coincidence spectroscopy was performed and a tentative decay scheme constructed up to a spin of 10hbar . B(E1)/B(E2) branching ratios were measured to be 5.5 +/- 1 times 10^{-7}fm ^{-2} and a provisional intrinsic dipole moment of Q_1 = 0.24 +/- 0.05efm for ^ {224}Ra was

  8. The Spectroscopic Evolution of the Symbiotic-like Recurrent Nova V407 Cygni During Its 2010 Outburst. 2. The Circumstellar Environment and the Aftermath

    NASA Technical Reports Server (NTRS)

    Shore, S. N.; Wahlgren, G. M.; Augusteijn, T.; Liimets, T.; Koubsky, P.; Slechta, M.; Votruba, V.

    2011-01-01

    contributor, and the lower states are collisionally quenched but emit from the low density surroundings. Absorption lines of Fe-peak ions formed in the Mira wind were visible as P Cyg profiles at low velocity before Day 69, around the time of the X-ray peak and we identified many absorption transitions without accompanying emission for metal lines. The H Balmer lines showed strong P Cyg absorption troughs that weakened during the 2010 observing period, through Day 128. The Fe-peak line profiles and flux variations were different for permitted and forbidden transitions: the E1 transitions were not visible after Day 128 but had shown a narrow peak superimposed on an extended (200 km/s) blue wing, while the M1 and E2 transitions persisted to Day 529, the last observation, and showed extended redshifted wings up of the same velocity. We distinguish the components from the shock, the photoionized environment, and the chromosphere and inner Mira wind using spectra taken more than one year after outburst. The multiple shells and radiative excitation phenomenology are similar to those recently cited for GRBs and SNIa .

  9. Neutrino spectroscopy with atoms and molecules

    NASA Astrophysics Data System (ADS)

    Fukumi, Atsushi; Kuma, Susumu; Miyamoto, Yuki; Nakajima, Kyo; Nakano, Itsuo; Nanjo, Hajime; Ohae, Chiaki; Sasao, Noboru; Tanaka, Minoru; Taniguchi, Takashi; Uetake, Satoshi; Wakabayashi, Tomonari; Yamaguchi, Takuya; Yoshimi, Akihiro; Yoshimura, Motohiko

    2012-12-01

    denoted by I(ω)) × (time-evolving dynamical factor), where ω is the photon energy. The constant factor Γ0 determines the overall rate in the unit of 1/time, and for Xe it is of the order of 1 Hz(n/1022 cm-3)3 (V/102 cm3). The dynamical factor is time dependent and is given by the space integrated quantity, over the entire target, of the product of the magnitude squared of the coherent polarization and the field strength (in the units of the maximally extractable energy density) stored inside the target. The asymptotic value of the time-evolving dynamical factor is given by the contribution of the field condensate accompanied by macroscopic coherence, which is calculated using the static limit of the master equation. With an appropriate choice of heavy target atoms or molecules such as Xe and I2 that have a large M1 × E1 matrix element between |e> and |g>, we show that one can determine three neutrino masses along with distinction of the mass hierarchy pattern (normal or inverted) by measuring the spectral shape I(ω). If one uses a target of available energy of a fraction of 1 eV, the most experimentally challenging observable, the Majorana CP phases may be determined, comparing the detected rate with differences of theoretical expectations which exist at the level of several percent. The Majorana CP-violating phase is expected to be crucial to the understanding of the matter-antimatter imbalance in our universe. Our master equation, when applied to E1 × E1 transitions such as pH2 vibrational Xv = 1 rArr 0, can describe explosive paired superradiance events in which most of the energy stored in |e> is released in the order of a few nanoseconds. The present paper is intended to be self-contained, explaining some details of related theoretical works in the past, and reports on new simulations and the ongoing experimental efforts of the project to realize neutrino mass spectroscopy using atoms/molecules.