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Sample records for 51v hyperfine coupling

  1. Hyperfine Coupling Constants from Internally Contracted Multireference Perturbation Theory.

    PubMed

    Shiozaki, Toru; Yanai, Takeshi

    2016-09-13

    We present an accurate method for calculating hyperfine coupling constants (HFCCs) based on the complete active space second-order perturbation theory (CASPT2) with full internal contraction. The HFCCs are computed as a first-order property using the relaxed CASPT2 spin-density matrix that takes into account orbital and configurational relaxation due to dynamical electron correlation. The first-order unrelaxed spin-density matrix is calculated from one- and two-body spin-free counterparts that are readily available in the CASPT2 nuclear gradient program [M. K. MacLeod and T. Shiozaki, J. Chem. Phys. 142, 051103 (2015)], whereas the second-order part is computed directly using the newly extended automatic code generator. The relaxation contribution is then calculated from the so-called Z-vectors that are available in the CASPT2 nuclear gradient program. Numerical results are presented for the CN and AlO radicals, for which the CASPT2 values are comparable (or, even superior in some cases) to the ones computed by the coupled-cluster and density matrix renormalization group methods. The HFCCs for the hexaaqua complexes with V(II), Cr(III), and Mn(II) are also presented to demonstrate the accuracy and efficiency of our code. PMID:27479148

  2. Breakdown of atomic hyperfine coupling in a deep optical-dipole trap

    NASA Astrophysics Data System (ADS)

    Neuzner, Andreas; Körber, Matthias; Dürr, Stephan; Rempe, Gerhard; Ritter, Stephan

    2015-11-01

    We experimentally study the breakdown of hyperfine coupling for an atom in a deep optical-dipole trap. One-color laser spectroscopy is performed at the resonance lines of a single 87Rb atom for a trap wavelength of 1064 nm. Evidence of hyperfine breakdown comes from three observations, namely, a nonlinear dependence of the transition frequencies on the trap intensity, a splitting of lines which are degenerate for small intensities, and the ability to drive transitions which would be forbidden by selection rules in the absence of hyperfine breakdown. From the data, we infer the hyperfine interval of the 5 P1 /2 state and the scalar and tensor polarizabilities for the 5 P3 /2 state.

  3. Ro-vibrational averaging of the isotropic hyperfine coupling constant for the methyl radical

    SciTech Connect

    Adam, Ahmad Y.; Jensen, Per; Yachmenev, Andrey; Yurchenko, Sergei N.

    2015-12-28

    We present the first variational calculation of the isotropic hyperfine coupling constant of the carbon-13 atom in the CH{sub 3} radical for temperatures T = 0, 96, and 300 K. It is based on a newly calculated high level ab initio potential energy surface and hyperfine coupling constant surface of CH{sub 3} in the ground electronic state. The ro-vibrational energy levels, expectation values for the coupling constant, and its temperature dependence were calculated variationally by using the methods implemented in the computer program TROVE. Vibrational energies and vibrational and temperature effects for coupling constant are found to be in very good agreement with the available experimental data. We found, in agreement with previous studies, that the vibrational effects constitute about 44% of the constant’s equilibrium value, originating mainly from the large amplitude out-of-plane bending motion and that the temperature effects play a minor role.

  4. Ro-vibrational averaging of the isotropic hyperfine coupling constant for the methyl radical.

    PubMed

    Adam, Ahmad Y; Yachmenev, Andrey; Yurchenko, Sergei N; Jensen, Per

    2015-12-28

    We present the first variational calculation of the isotropic hyperfine coupling constant of the carbon-13 atom in the CH3 radical for temperatures T = 0, 96, and 300 K. It is based on a newly calculated high level ab initio potential energy surface and hyperfine coupling constant surface of CH3 in the ground electronic state. The ro-vibrational energy levels, expectation values for the coupling constant, and its temperature dependence were calculated variationally by using the methods implemented in the computer program TROVE. Vibrational energies and vibrational and temperature effects for coupling constant are found to be in very good agreement with the available experimental data. We found, in agreement with previous studies, that the vibrational effects constitute about 44% of the constant's equilibrium value, originating mainly from the large amplitude out-of-plane bending motion and that the temperature effects play a minor role. PMID:26723670

  5. Ro-vibrational averaging of the isotropic hyperfine coupling constant for the methyl radical

    NASA Astrophysics Data System (ADS)

    Adam, Ahmad Y.; Yachmenev, Andrey; Yurchenko, Sergei N.; Jensen, Per

    2015-12-01

    We present the first variational calculation of the isotropic hyperfine coupling constant of the carbon-13 atom in the CH3 radical for temperatures T = 0, 96, and 300 K. It is based on a newly calculated high level ab initio potential energy surface and hyperfine coupling constant surface of CH3 in the ground electronic state. The ro-vibrational energy levels, expectation values for the coupling constant, and its temperature dependence were calculated variationally by using the methods implemented in the computer program TROVE. Vibrational energies and vibrational and temperature effects for coupling constant are found to be in very good agreement with the available experimental data. We found, in agreement with previous studies, that the vibrational effects constitute about 44% of the constant's equilibrium value, originating mainly from the large amplitude out-of-plane bending motion and that the temperature effects play a minor role.

  6. Vibrational Averaging of the Isotropic Hyperfine Coupling Constants for the Methyl Radical

    NASA Astrophysics Data System (ADS)

    Adam, Ahmad; Jensen, Per; Yachmenev, Andrey; Yurchenko, Sergei N.

    2014-06-01

    Electronic contributions to molecular properties are often considered as the major factor and usually reported in the literature without ro-vibrational corrections. However, there are many cases where the nuclear motion contributions are significant and even larger than the electronic contribution. In order to obtain accurate theoretical predictions, nuclear motion effects on molecular properties need to be taken into account. The computed isotropic hyperfine coupling constants for the nonvibrating methyl radical CH_3 are far from the experimental values. For CH_3, we have calculated the vibrational-state-dependence of the isotropic hyperfine coupling constant in the electronic ground state. The vibrational wavefunctions used in the averaging procedure were obtained variationally with the TROVE program. Analytical representations for the potential energy surfaces and the hyperfine coupling constant surfaces are obtained in least-squares fitting procedures. Thermal averaging has been carried out for molecules in thermal equilibrium, i.e., with Boltzmann-distributed populations. The calculation methods and the results will be discussed in detail.

  7. Prediction of nitroxide hyperfine coupling constants in solution from combined nanosecond scale simulations and quantum computations

    NASA Astrophysics Data System (ADS)

    Houriez, Céline; Ferré, Nicolas; Masella, Michel; Siri, Didier

    2008-06-01

    We present a combined theoretical approach based on analyzing molecular dynamics trajectories (at the nanosecond scale) generated by use of classical polarizable force fields and on quantum calculations to compute averaged hyperfine coupling constants. That method is used to estimate the constant of a prototypical nitroxide: the dimethylnitroxide. The molecule is embedded during the simulations in a cubic box containing about 500 water molecules and the molecular dynamics is generated using periodic conditions. Once the trajectories are achieved, the nitroxide and its first hydration shell molecules are extracted, and the coupling constants are computed by considering the latter aggregates by means of quantum computations. However, all the water molecules of the bulk are also accounted for during those computations by means of the electrostatic potential fitted method. Our results exhibit that in order to predict accurate and reliable coupling constants, one needs to describe carefully the out-of-plane motion of the nitroxide nitrogen and to sample trajectories with a time interval of 400 fs at least to generate an uncorrelated large set of nitroxide structures. Compared to Car-Parrinello molecular dynamics techniques, our approach can be used readily to compute hyperfine coupling constants of large systems, such as nitroxides of great size interacting with macromolecules such as proteins or polymers.

  8. Prediction of nitroxide hyperfine coupling constants in solution from combined nanosecond scale simulations and quantum computations.

    PubMed

    Houriez, Céline; Ferré, Nicolas; Masella, Michel; Siri, Didier

    2008-06-28

    We present a combined theoretical approach based on analyzing molecular dynamics trajectories (at the nanosecond scale) generated by use of classical polarizable force fields and on quantum calculations to compute averaged hyperfine coupling constants. That method is used to estimate the constant of a prototypical nitroxide: the dimethylnitroxide. The molecule is embedded during the simulations in a cubic box containing about 500 water molecules and the molecular dynamics is generated using periodic conditions. Once the trajectories are achieved, the nitroxide and its first hydration shell molecules are extracted, and the coupling constants are computed by considering the latter aggregates by means of quantum computations. However, all the water molecules of the bulk are also accounted for during those computations by means of the electrostatic potential fitted method. Our results exhibit that in order to predict accurate and reliable coupling constants, one needs to describe carefully the out-of-plane motion of the nitroxide nitrogen and to sample trajectories with a time interval of 400 fs at least to generate an uncorrelated large set of nitroxide structures. Compared to Car-Parrinello molecular dynamics techniques, our approach can be used readily to compute hyperfine coupling constants of large systems, such as nitroxides of great size interacting with macromolecules such as proteins or polymers. PMID:18601346

  9. Femtosecond frequency comb measurement of absolute frequencies and hyperfine coupling constants in cesium vapor

    SciTech Connect

    Stalnaker, Jason E.; Mbele, Vela; Gerginov, Vladislav; Fortier, Tara M.; Diddams, Scott A.; Hollberg, Leo; Tanner, Carol E.

    2010-04-15

    We report measurements of absolute transition frequencies and hyperfine coupling constants for the 8S{sub 1/2}, 9S{sub 1/2}, 7D{sub 3/2}, and 7D{sub 5/2} states in {sup 133}Cs vapor. The stepwise excitation through either the 6P{sub 1/2} or 6P{sub 3/2} intermediate state is performed directly with broadband laser light from a stabilized femtosecond laser optical-frequency comb. The laser beam is split, counterpropagated, and focused into a room-temperature Cs vapor cell. The repetition rate of the frequency comb is scanned and we detect the fluorescence on the 7P{sub 1/2,3/2{yields}}6S{sub 1/2} branches of the decay of the excited states. The excitations to the different states are isolated by the introduction of narrow-bandwidth interference filters in the laser beam paths. Using a nonlinear least-squares method we find measurements of transition frequencies and hyperfine coupling constants that are in agreement with other recent measurements for the 8S state and provide improvement by 2 orders of magnitude over previously published results for the 9S and 7D states.

  10. Determination of the hyperfine coupling constant of the cesium 7S1/2 state

    NASA Astrophysics Data System (ADS)

    Yang, Guang; Wang, Jie; Yang, Baodong; Wang, Junmin

    2016-08-01

    We report the hyperfine splitting (HFS) measurement of the cesium (Cs) 7S1/2 state by optical–optical double-resonance spectroscopy with the Cs 6S1/2–6P3/2–7S1/2 (852 nm  +  1470 nm) ladder-type system. The HFS frequency calibration is performed by employing a phase-type waveguide electro-optic modulator together with a stable confocal Fabry–Perot cavity. From the measured HFS between the F″  =  3 and F″  =  4 manifolds of the Cs 7S1/2 state (HFS  =  2183.273  ±  0.062 MHz), we have determined the magnetic dipole hyperfine coupling constant (A  =  545.818  ±  0.016 MHz), which is in good agreement with the previous work but much more precise.

  11. Density functional theory investigation of hyperfine coupling constants in peroxyl radicals

    NASA Astrophysics Data System (ADS)

    Wetmore, Stacey D.; Boyd, Russell J.; Eriksson, Leif A.

    1997-05-01

    The geometries and 17O hyperfine coupling constants in several peroxyl radicals have been determined through the use of density functional theory. Becke's three-parameter hybrid exchange functional (B3) together with the correlation functional of Lee, Yang, and Parr (LYP) in combination with a variety of basis sets was used to study basis set effects. Subsequently, the effects of different gradient-correlated functionals were also examined. Results comparable to experimental values are obtained for all of the alkyl peroxyl radicals at the B3LYP level with IGLO-III or s-shell decontracted IGLO-III, 6-311G(d,p), 6-311+G(2df,p), and the augmented correlation-consistent polarized-valence triple-zeta basis set of D. E. Woon and T. H. Dunning [J. Chem. Phys. 98, 1358 (1993)], R. E. Kendall, T. H. Dunning, and R. J. Harrison [J. Chem. Phys. 96, 6796 (1992)], and T. H. Dunning [J. Chem. Phys. 90, 1007 (1989)]. Calculations imply that the spin density ratio between the inner and outer oxygens is 0.3:0.7, supporting earlier theoretical work [S. L. Boyd, R. J. Boyd, and L. R. C. Barclay, J. Am. Chem. Soc. 112, 5724 (1990)]. Erratic and strongly fluctuating results are exhibited for the fluoroperoxyl radical. Geometries close to the experimental values can be obtained at the B3LYP level, but at the expense of considerable spin contamination. A high degree of spin contamination can also be observed in calculations of the hyperfine coupling constants for this molecule. Possible explanations for the apparent failure to obtain converged results for FOO, apart from the considerable spin contamination, include vibrational, multireference, and matrix effects.

  12. Scalar Relativistic Computations and Localized Orbital Analyses of Nuclear Hyperfine Coupling and Paramagnetic NMR Chemical Shifts

    SciTech Connect

    Aquino, Fredy W.; Pritchard, Ben; Autschbach, Jochen

    2012-02-14

    A method is reported by which calculated hyperfine coupling constants (HFCCs) and paramagnetic NMR (pNMR) chemical shifts can be analyzed in a chemically intuitive way by decomposition into contributions from localized molecular orbitals (LMOs). A new module for density functional calculations with nonhybrid functionals, global hybrids, and range-separated hybrids, utilizing the two-component relativistic zeroth-order regular approximation (ZORA), has been implemented in the parallel open-source NWChem quantum chemistry package. Benchmark results are reported for a test set of few-atom molecules with light and heavy elements. Finite nucleus effects on ¹⁹⁹Hg HFCCs are shown to be on the order of -11 to -15%. A proof of concept for the LMO analysis is provided for the metal and fluorine HFCCs of TiF₃ and NpF₆. Calculated pNMR chemical shifts are reported for the 2-methylphenyl-t-butylnitroxide radical and for five cyclopentadienyl (Cp) sandwich complexes with 3d metals. Nickelocene and vanadocene carbon pNMR shifts are analyzed in detail, demonstrating that the large carbon pNMR shifts calculated as +1540 for Ni (exptl.: +1514) and -443 for V (exptl.: -510) are caused by different spin-polarization mechanisms. For Ni, Cp to Ni π back-donation dominates the result, whereas for vanadocene, V to Cp σ donation with relaxation of the carbon 1s shells can be identified as the dominant mechanism.

  13. Hyperfine coupling and spin polarization in the bulk of the topological insulator Bi2Se3

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, S.; Krämer, S.; Mayaffre, H.; Legg, H. F.; Orlita, M.; Berthier, C.; Horvatić, M.; Martinez, G.; Potemski, M.; Piot, B. A.; Materna, A.; Strzelecka, G.; Hruban, A.

    2015-02-01

    Nuclear magnetic resonance (NMR) and transport measurements have been performed at high magnetic fields and low temperatures in a series of n -type Bi2Se3 crystals. In low-density samples, a complete spin polarization of the electronic system is achieved, as observed from the saturation of the isotropic component of the 209Bi NMR shift above a certain magnetic field. The corresponding spin splitting, defined in the phenomenological approach of a 3D electron gas with a large (spin-orbit-induced) effective g factor, scales as expected with the Fermi energy independently determined by simultaneous transport measurements. Both the effective electronic g factor and the "contact" hyperfine coupling constant are precisely determined. The magnitude of this latter reveals a nonnegligible s character of the electronic wave function at the bottom of the conduction band. Our results show that the bulk electronic spin polarization can be directly probed via NMR and pave the way for future NMR investigations of the electronic states in Bi-based topological insulators.

  14. SIMPRE1.2: Considering the hyperfine and quadrupolar couplings and the nuclear spin bath decoherence.

    PubMed

    Cardona-Serra, Salvador; Escalera-Moreno, Luis; Baldoví, José J; Gaita-Ariño, Alejandro; Clemente-Juan, Juan M; Coronado, Eugenio

    2016-05-15

    SIMPRE is a fortran77 code which uses an effective electrostatic model of point charges to predict the magnetic behavior of rare-earth-based mononuclear complexes. In this article, we present SIMPRE1.2, which now takes into account two further phenomena. First, SIMPRE now considers the hyperfine and quadrupolar interactions within the rare-earth ion, resulting in a more complete and realistic set of energy levels and wave functions. Second, and to widen SIMPRE's predictive capabilities regarding potential molecular spin qubits, it now includes a routine that calculates an upper-bound estimate of the decoherence time considering only the dipolar coupling between the electron spin and the surrounding nuclear spin bath. Additionally, SIMPRE now allows the user to introduce the crystal field parameters manually. Thus, we are able to demonstrate the new features using as examples (i) a Gd-based mononuclear complex known for its properties both as a single ion magnet and as a coherent qubit and (ii) an Er-based mononuclear complex. © 2016 Wiley Periodicals, Inc. PMID:26833799

  15. Estimating the hyperfine coupling parameters of the avian compass by comprehensively considering the available experimental results.

    PubMed

    Xu, Bao-Ming; Zou, Jian; Li, Jun-Gang; Shao, Bin

    2013-09-01

    Migratory birds can utilize the geomagnetic field for orientation and navigation through a widely accepted radical-pair mechanism. Although many theoretical works have been done, the available experimental results have not been fully considered, especially the temporary disorientation induced by the field which is increased by 30% of the geomagnetic field and the disorientation of the very weak resonant field of 15 nT. In this paper, we consider the monotonicity of the singlet yield angular profile as the prerequisite of direction sensitivity, and find that for some optimal values of the hyperfine coupling parameters (that is, the order of 10^{-7}∼10^{-6} meV) the experimental results available so far can be satisfied. We also investigate the effects of two decoherence environments and demonstrate that, in order to satisfy the available experimental results, the decoherence rate should be lower than the recombination rate. Finally, we investigate the effects of the fluctuating magnetic noises and find that the vertical noise destroys the monotonicity of the profile completely, but the parallel noise preserves the monotonicity perfectly and even can enhance the direction sensitivity. PMID:24125290

  16. The β-phosphorus hyperfine coupling constant in nitroxides: 6. Solvent effects in non-cyclic nitroxides.

    PubMed

    Audran, Gérard; Bosco, Lionel; Nkolo, Paulin; Bikanga, Raphael; Brémond, Paul; Butscher, Teddy; Marque, Sylvain R A

    2016-04-12

    In two recent articles (Org. Biomol. Chem., 2015 and 2016), we showed that changes in the phosphorus hyperfine coupling constant aP at position β in β-phosphorylated nitroxides can be dramatic. Such changes were applied to the titration of water in organic solvents and conversely of organic solvents in water. One of the molecules tested was a non-cyclic nitroxide meaning that a thorough investigation of the solvent effect on the EPR hyperfine coupling constant is timely due. In this article, we show that the aP of persistent non-cyclic β-phosphorylated nitroxides decrease with the normalized polarity Reichardt's constant E(N)T. The Koppel-Palm and Kalmet-Abboud-Taft relationships were applied to gain deeper insight into the effects influencing aN and aP: polarity/polarizability, hydrogen bond donor properties, and the structuredness of the cybotactic region. PMID:26986555

  17. Relativistic Density Functional Calculations of Hyperfine Coupling with Variational versus Perturbational Treatment of Spin-Orbit Coupling.

    PubMed

    Verma, Prakash; Autschbach, Jochen

    2013-04-01

    Different approaches are compared for relativistic density functional theory (DFT) and Hartree-Fock (HF) calculations of electron-nucleus hyperfine coupling (HFC) in molecules with light atoms, in transition metal complexes, and in selected actinide halide complexes with a formal metal 5f(1) configuration. The comparison includes hybrid density functionals with range-separated exchange. Within the variationally stable zeroth-order regular approximation (ZORA) relativistic framework, the HFC is obtained (i) with a linear response (LR) method where spin-orbit (SO) coupling is treated as a linear perturbation, (ii) with a spin-polarized approach closely related to a DFT method for calculating magnetic anisotropy (MA) previously devised by van Wüllen et al. where SO coupling is included variationally, (iii) with a quasi-restricted variational SO method previously devised by van Lenthe, van der Avoird, and Wormer (LWA). The MA and LWA approaches for HFC calculations were implemented in the open-source NWChem quantum chemistry package as part of this study. The methodology extends recent implementations for calculations of electronic g-factors (J. Chem. Theor. Comput.2013, 9, 1052). The impact of electron correlation (DFT vs HF) and DFT delocalization errors, the effects of spin-polarization, the importance of treating spin-orbit coupling beyond first-order, and the magnitude of finite-nucleus effects, are investigated. Similar to calculations of g-factors, the MA approach in conjunction with hybrid functionals performs reasonably well for theoretical predictions of HFC in a wide range of scenarios. PMID:26583544

  18. A study of magnetoresistance in organic semiconductors with varying strengths of hyperfine and spin-orbit coupling

    NASA Astrophysics Data System (ADS)

    Sheng, Yugang

    This thesis concerns itself with the scientific study of the recently discovered organic magnetoresistance (OMAR) whose underlying mechanism is currently not known with certainty. As an introduction, we briefly review the major findings from prior work done by my colleagues. They found that OMAR can be as large as ≈10% magnetoresistance at 10 mT magnetic fields at room temperature. Both OMAR and other kinds of magnetic field effect data in organics can be fitted using the empirical laws B2/B2+B20 or B2/(|B| + B0)2, dependent on material. The fitting parameter B0 is a measure of the characteristic magnetic field strength of OMAR. We explore the dependence of B0 on material parameters to clarify the origin of OMAR. Various pi-conjugated semiconductor OMAR devices were studied to explore the possibility that hyperfine interaction causes OMAR. For a quantitative analysis of the experiments, we developed a theoretical fitting formula to relate B0 to the hyperfine coupling strength. In addition, organic materials with different spin-orbit coupling strengths were also measured. Fluorescence and phosphorescence spectroscopies were used to estimate the spin-orbit coupling strength from the measured spectra. For analyzing our measurements, we developed a fitting formula from the time-dependent Schrodinger equation that takes into account the combined effect of hyperfine and spin-orbit coupling on spin-dynamics. We found that in the case of strong spin-orbit coupling, it dominates the behavior, resulting in magnetic field effect traces that are much wider than those in ordinary organics. However, a small cone remains at zero field with a width equal to the hyperfine coupling strength. We find qualitative agreement between the experimental results and the model. We also investigated the question whether OMAR is related to an excitonic effect, or is primarily a transport effect. We measured the magnetic field effects on current, photocurrent and electroluminescence to address

  19. Further insights into the environmental effects on the computed hyperfine coupling constants of nitroxides in aqueous solution.

    PubMed

    Houriez, Céline; Ferré, Nicolas; Siri, Didier; Masella, Michel

    2009-11-12

    We investigated the main two factors influencing the mean hyperfine coupling constants of small nitroxide radicals in aqueous solution, i.e., the out-of-plane displacement of their nitrogen atom and the environmental effects (solvent effects), by means of the approach we previously developed and fine-tuned to study the solvation of the dimethyl nitroxide radical. Our methodology efficiently combines classical molecular dynamics based on a polarizable force field at the nanosecond scale and quantum mechanics/molecular mechanics (QM/MM) computations to account for the bulk instantaneous electrostatic environmental effect. Our method has been applied to five small nitroxides, namely methyl nitroxide, ethyl nitroxide, dimethyl nitroxide, di-tert-butyl nitroxide, and PROXYL. The theoretical nitrogen hyperfine coupling constant values for the five nitroxides in solution are in good agreement with experiment (difference of 0.3 G on average). Our approach showed that the solvent shift in nitroxide hyperfine coupling constants is almost constant whatever the nitroxide, and, particularly, whatever the nitroxide NO moiety's accessibility to the solvent. This result contrasts with earlier results derived from 10 ps scale trajectories based on Car-Parrinello molecular dynamics approach. However, we show that if we consider on average these latter results, they are in agreement with our conclusion. We also present an attempt to identify the origin of this result by analyzing the solvent contributions in terms of effects of the nitroxide first hydration shell and of the bulk, and by investigating the relation between these two contributions and the solvent structure at the vicinity of the NO moiety. PMID:19845322

  20. Hyperfine-induced hysteretic funnel structure in spin blockaded tunneling current of coupled vertical quantum dots at low magnetic field

    SciTech Connect

    Leary, A.; Wicha, A.; Harack, B.; Coish, W. A.; Hilke, M.; Yu, G.; Gupta, J. A.; Payette, C.; Austing, D. G.

    2013-12-04

    We outline the properties of the hyperfine-induced funnel structure observed in the two-electron spin blockade region of a weakly coupled vertical double quantum dot device. Hysteretic steps in the leakage current occur due to dynamic nuclear polarization when either the bias voltage or the magnetic field is swept up and down. When the bias voltage is swept, an intriguing ∼3 mT wide cusp near 0 T appears in the down-sweep position, and when the magnetic field is swept, the current at 0 T can be switched from 'low' to 'high' as the bias is increased.

  1. Hyperfine-induced hysteretic funnel structure in spin blockaded tunneling current of coupled vertical quantum dots at low magnetic field

    NASA Astrophysics Data System (ADS)

    Leary, A.; Wicha, A.; Harack, B.; Coish, W. A.; Hilke, M.; Yu, G.; Payette, C.; Gupta, J. A.; Austing, D. G.

    2013-12-01

    We outline the properties of the hyperfine-induced funnel structure observed in the two-electron spin blockade region of a weakly coupled vertical double quantum dot device. Hysteretic steps in the leakage current occur due to dynamic nuclear polarization when either the bias voltage or the magnetic field is swept up and down. When the bias voltage is swept, an intriguing ˜3 mT wide cusp near 0 T appears in the down-sweep position, and when the magnetic field is swept, the current at 0 T can be switched from "low" to "high" as the bias is increased.

  2. Massively parallel implementations of coupled-cluster methods for electron spin resonance spectra. I. Isotropic hyperfine coupling tensors in large radicals

    NASA Astrophysics Data System (ADS)

    Verma, Prakash; Perera, Ajith; Morales, Jorge A.

    2013-11-01

    Coupled cluster (CC) methods provide highly accurate predictions of molecular properties, but their high computational cost has precluded their routine application to large systems. Fortunately, recent computational developments in the ACES III program by the Bartlett group [the OED/ERD atomic integral package, the super instruction processor, and the super instruction architecture language] permit overcoming that limitation by providing a framework for massively parallel CC implementations. In that scheme, we are further extending those parallel CC efforts to systematically predict the three main electron spin resonance (ESR) tensors (A-, g-, and D-tensors) to be reported in a series of papers. In this paper inaugurating that series, we report our new ACES III parallel capabilities that calculate isotropic hyperfine coupling constants in 38 neutral, cationic, and anionic radicals that include the 11B, 17O, 9Be, 19F, 1H, 13C, 35Cl, 33S,14N, 31P, and 67Zn nuclei. Present parallel calculations are conducted at the Hartree-Fock (HF), second-order many-body perturbation theory [MBPT(2)], CC singles and doubles (CCSD), and CCSD with perturbative triples [CCSD(T)] levels using Roos augmented double- and triple-zeta atomic natural orbitals basis sets. HF results consistently overestimate isotropic hyperfine coupling constants. However, inclusion of electron correlation effects in the simplest way via MBPT(2) provides significant improvements in the predictions, but not without occasional failures. In contrast, CCSD results are consistently in very good agreement with experimental results. Inclusion of perturbative triples to CCSD via CCSD(T) leads to small improvements in the predictions, which might not compensate for the extra computational effort at a non-iterative N7-scaling in CCSD(T). The importance of these accurate computations of isotropic hyperfine coupling constants to elucidate experimental ESR spectra, to interpret spin-density distributions, and to

  3. Massively parallel implementations of coupled-cluster methods for electron spin resonance spectra. I. Isotropic hyperfine coupling tensors in large radicals

    SciTech Connect

    Verma, Prakash; Morales, Jorge A.; Perera, Ajith

    2013-11-07

    Coupled cluster (CC) methods provide highly accurate predictions of molecular properties, but their high computational cost has precluded their routine application to large systems. Fortunately, recent computational developments in the ACES III program by the Bartlett group [the OED/ERD atomic integral package, the super instruction processor, and the super instruction architecture language] permit overcoming that limitation by providing a framework for massively parallel CC implementations. In that scheme, we are further extending those parallel CC efforts to systematically predict the three main electron spin resonance (ESR) tensors (A-, g-, and D-tensors) to be reported in a series of papers. In this paper inaugurating that series, we report our new ACES III parallel capabilities that calculate isotropic hyperfine coupling constants in 38 neutral, cationic, and anionic radicals that include the {sup 11}B, {sup 17}O, {sup 9}Be, {sup 19}F, {sup 1}H, {sup 13}C, {sup 35}Cl, {sup 33}S,{sup 14}N, {sup 31}P, and {sup 67}Zn nuclei. Present parallel calculations are conducted at the Hartree-Fock (HF), second-order many-body perturbation theory [MBPT(2)], CC singles and doubles (CCSD), and CCSD with perturbative triples [CCSD(T)] levels using Roos augmented double- and triple-zeta atomic natural orbitals basis sets. HF results consistently overestimate isotropic hyperfine coupling constants. However, inclusion of electron correlation effects in the simplest way via MBPT(2) provides significant improvements in the predictions, but not without occasional failures. In contrast, CCSD results are consistently in very good agreement with experimental results. Inclusion of perturbative triples to CCSD via CCSD(T) leads to small improvements in the predictions, which might not compensate for the extra computational effort at a non-iterative N{sup 7}-scaling in CCSD(T). The importance of these accurate computations of isotropic hyperfine coupling constants to elucidate

  4. Temperature-scanned magnetic resonance and the evidence of two-way transfer of a nitrogen nuclear spin hyperfine interaction in coupled NV-N pairs in diamond

    NASA Astrophysics Data System (ADS)

    Babunts, R. A.; Soltamova, A. A.; Tolmachev, D. O.; Soltamov, V. A.; Gurin, A. S.; Anisimov, A. N.; Preobrazhenskii, V. L.; Baranovi, P. G.

    2012-06-01

    New method for the detection of magnetic resonance signals versus temperature is developed on the basis of the temperature dependence of the spin Hamiltonian parameters of the paramagnetic system under investigation. The implementation of this technique is demonstrated on the nitrogen-vacancy (NV) centers in diamonds. Single NV defects and their ensembles are suggested to be almost inertialess temperature sensors. The hyperfine structure of the 14N nitrogen nuclei of the nitrogen-vacancy center appears to be resolved in the hyperfine structure characteristic of the hyperfine interaction between NV and an N s center (substitutional nitrogen impurity) in the optically detected magnetic resonance spectra of the molecular NV-N s complex. Thus, we show that a direct evidence of the two-way transfer of a nitrogen nuclear spin hyperfine interaction in coupled NV-N s pairs was observed. It is shown that more than 3-fold enhancement of the NV optically detected magnetic resonance signal can be achieved by using water as a collection optics medium.

  5. A path integral molecular dynamics study of the hyperfine coupling constants of the muoniated and hydrogenated acetone radicals

    NASA Astrophysics Data System (ADS)

    Oba, Yuki; Kawatsu, Tsutomu; Tachikawa, Masanori

    2016-08-01

    The on-the-fly ab initio density functional path integral molecular dynamics (PIMD) simulations, which can account for both the nuclear quantum effect and thermal effect, were carried out to evaluate the structures and "reduced" isotropic hyperfine coupling constants (HFCCs) for muoniated and hydrogenated acetone radicals (2-muoxy-2-propyl and 2-hydoxy-2-propyl) in vacuo. The reduced HFCC value from a simple geometry optimization calculation without both the nuclear quantum effect and thermal effect is -8.18 MHz, and that by standard ab initio molecular dynamics simulation with only the thermal effect and without the nuclear quantum effect is 0.33 MHz at 300 K, where these two methods cannot distinguish the difference between muoniated and hydrogenated acetone radicals. In contrast, the reduced HFCC value of the muoniated acetone radical by our PIMD simulation is 32.1 MHz, which is about 8 times larger than that for the hydrogenated radical of 3.97 MHz with the same level of calculation. We have found that the HFCC values are highly correlated with the local molecular structures; especially, the Mu—O bond length in the muoniated acetone radical is elongated due to the large nuclear quantum effect of the muon, which makes the expectation value of the HFCC larger. Although our PIMD result calculated in vacuo is about 4 times larger than the measured experimental value in aqueous solvent, the ratio of these HFCC values between muoniated and hydrogenated acetone radicals in vacuo is in reasonable agreement with the ratio of the experimental values in aqueous solvent (8.56 MHz and 0.9 MHz); the explicit presence of solvent molecules has a major effect on decreasing the reduced muon HFCC of in vacuo calculations for the quantitative reproduction.

  6. Covalency in La2CuO4: A study of 17O hyperfine couplings in the paramagnetic phase

    NASA Astrophysics Data System (ADS)

    Walstedt, R. E.; Cheong, S.-W.

    2001-07-01

    17O nuclear magnetic resonance spectra from single crystals of La2CuO4 are reported for temperatures ranging from 285 to 800 K. Hyperfine tensor data for the planar sites are analyzed using a spin Hamiltonian model that includes spin-orbit coupling effects. The results show a 7.7% hybridization effect of the oxygen 2pσ orbital from a single copper neighbor, in good agreement with recent density-functional (DF) calculations by Hüsser et al. (HSSM). A large, positive isotropic shift component is also reported, presumably originating from the contact interaction with a hybridized 2s orbital component. First-order quadrupolar-splitting data lead to complete characterization of the electric-field gradient (EFG) tensor, which varies only slightly with temperature up to 800 K. EFG tensors for both doped and undoped La2CuO4 are fitted with a two-component model, which incorporates a substantial anisotropy in for the 2pσ wave functions, an effect that originated in the DF calculations of HSSM. This analysis reveals an increased charge density on the planar oxygens for the superconducting phase, in accord with the original Zhang-Rice model. However, the increase is found to correspond to only ~80% of the nominal doped-hole density, corroborating a similar conclusion reached recently by Hammel et al. Regarding the anomalous spin HF interaction reported in a previous paper for the weakly ferromagnetic state, the present results show that its effects extend all the way to and slightly beyond the orthorhombic-tetragonal phase boundary (TO-T~=550 K). Further, the predominant 2s contact HF interaction reported here supports the notion, suggested earlier, that a 2s admixture underlies the anomaly. However, the basic mechanism of the anomaly remains obscure.

  7. Hyperfine coupling constants on inner-sphere water molecules of Gd(III)-based MRI contrast agents.

    PubMed

    Esteban-Gómez, David; de Blas, Andrés; Rodríguez-Blas, Teresa; Helm, Lothar; Platas-Iglesias, Carlos

    2012-11-12

    Herein we present a theoretical investigation of the hyperfine coupling constants (HFCCs) on the inner-sphere water molecules of [Gd(H(2)O)(8)](3+) and different Gd(III)-based magnetic resonance imaging contrast agents such as [Gd(DOTA)(H(2)O)](-), [Gd(DTPA)(H(2)O)](2-), [Gd(DTPA-BMA)(H(2)O)] and [Gd(HP-DO3A)(H(2)O)]. DFT calculations performed on the [Gd(H(2)O)(8)](3+) model system show that both hybrid-GGA functionals (BH&HLYP, B3PW91 and PBE1PBE) and the hybrid meta-GGA functional TPSSh provide (17)O HFCCs in close agreement with the experimental data. The use of all-electron relativistic approaches based on the DKH2 approximation and the use of relativistic effective core potentials (RECP) provide results of essentially the same quality. The accurate calculation of HFCCs on the [Gd(DOTA)(H(2)O)](-), [Gd(DTPA)(H(2)O)](2-), [Gd(DTPA-BMA)(H(2)O)] and [Gd(HP-DO3A)(H(2)O)] complexes requires an adequate description of solvent effects. This was achieved by using a mixed cluster/continuum approach that includes explicitly two second-sphere water molecules. The calculated isotropic (17)O HFCCs (A(iso)) fall within the range 0.40-0.56 MHz, and show deviations from the corresponding experimental values typically lower than 0.05 MHz. The A(iso) values are significantly affected by the distance between the oxygen atom of the coordinated water molecule and the Gd(III) ion, as well as by the orientation of the water molecule plane with respect to the Gd-O vector. (1)H HFCCs of coordinated water molecules and (17)O HFCCs of second-sphere water molecules take values close to zero. PMID:22927182

  8. Application of relativistic coupled-cluster theory to heavy atomic systems with strongly interacting configurations: Hyperfine interactions in {sup 207}Pb{sup +}

    SciTech Connect

    Sahoo, Bijaya K.; Chaudhuri, Rajat K.; Das, B.P.; Merlitz, Holger; Mukherjee, Debashis

    2005-09-15

    We report the results of our calculations of the magnetic dipole hyperfine constants for the ground and low-lying excited states of Pb{sup +} using the relativistic coupled-cluster theory. The spectacular role of correlation effects particularly for the 6p{sub 3/2} state is highlighted. The relative importance of core polarization and pair correlation effects have been studied and the result obtained for the ground state is different from that of Ba{sup +}, which has a single s valence electron.

  9. Power spectra and auto correlation analysis of hyperfine-induced long period oscillations in the tunneling current of coupled quantum dots

    NASA Astrophysics Data System (ADS)

    Harack, B.; Leary, A.; Coish, W. A.; Hilke, M.; Yu, G.; Payette, C.; Gupta, J. A.; Austing, D. G.

    2013-12-01

    We outline power spectra and auto correlation analysis performed on temporal oscillations in the tunneling current of coupled vertical quantum dots. The current is monitored for ˜2325 s blocks as the magnetic field is stepped through a high bias feature displaying hysteresis and switching: hallmarks of the hyperfine interaction. Quasi-periodic oscillations of ˜2 pA amplitude and of ˜100 s period are observed in the current inside the hysteretic feature. Compared to the baseline current outside the hysteretic feature the power spectral density is enhanced by up to three orders of magnitude and the auto correlation displays clear long lived oscillations about zero.

  10. Power spectra and auto correlation analysis of hyperfine-induced long period oscillations in the tunneling current of coupled quantum dots

    SciTech Connect

    Harack, B.; Leary, A.; Coish, W. A.; Hilke, M.; Yu, G.; Gupta, J. A.; Payette, C.; Austing, D. G.

    2013-12-04

    We outline power spectra and auto correlation analysis performed on temporal oscillations in the tunneling current of coupled vertical quantum dots. The current is monitored for ∼2325 s blocks as the magnetic field is stepped through a high bias feature displaying hysteresis and switching: hallmarks of the hyperfine interaction. Quasi-periodic oscillations of ∼2 pA amplitude and of ∼100 s period are observed in the current inside the hysteretic feature. Compared to the baseline current outside the hysteretic feature the power spectral density is enhanced by up to three orders of magnitude and the auto correlation displays clear long lived oscillations about zero.

  11. Determination of the hyperfine coupling with the remote nitrogen in the VO 2+—(imidazole) 4 complex by ESEEM spectroscopy

    NASA Astrophysics Data System (ADS)

    Dikanov, Sergei A.; Burgard, Christian; Hüttermann, Jürgen

    1993-09-01

    Electron spin echo envelope modulation experiments are presented from 15N-substituted VO 2+—(imidazole) 4 complexes which demonstrate the interaction of the paramagnetic ion with the remote, weakly coupled ring nitrogen. The hyperfine parameters derived show that the interaction is about twenty times smaller than with the directly coordinated nitrogen of imidazole, a ratio comparable to that derived from known values for Cu 2+—(imidazole) 4. These findings question results reported from previous ENDOR work on VO 2+—(imidazole) 4.

  12. Theory of box-model hyperfine couplings and transport signatures of long-range nuclear-spin coherence in a quantum-dot spin valve

    NASA Astrophysics Data System (ADS)

    Chesi, Stefano; Coish, W. A.

    2015-06-01

    We have theoretically analyzed coherent nuclear-spin dynamics induced by electron transport through a quantum-dot spin valve. The hyperfine interaction between electron and nuclear spins in a quantum dot allows for the transfer of angular momentum from spin-polarized electrons injected from ferromagnetic or half-metal leads to the nuclear spin system under a finite voltage bias. Accounting for a local nuclear-spin dephasing process prevents the system from becoming stuck in collective dark states, allowing a large nuclear polarization to be built up in the long-time limit. After reaching a steady state, reversing the voltage bias induces a transient current response as the nuclear polarization is reversed. Long-range nuclear-spin coherence leads to a strong enhancement of spin-flip transition rates (by an amount proportional to the number of nuclear spins) and is revealed by an intense current burst, analogous to superradiant light emission. The crossover to a regime with incoherent spin flips occurs on a relatively long-time scale, on the order of the single-nuclear-spin dephasing time, which can be much longer than the time scale for the superradiant current burst. This conclusion is confirmed through a general master equation. For the two limiting regimes (coherent/incoherent spin flips), the general master equation recovers our simpler treatment based on rate equations, but is also applicable at intermediate dephasing. Throughout this work, we assume uniform hyperfine couplings, which yield the strongest coherent enhancement. We propose realistic strategies, based on isotopic modulation and wave-function engineering in core-shell nanowires, to realize this analytically solvable "box-model" of hyperfine couplings.

  13. Evaluation of nitrogen nuclear hyperfine and quadrupole coupling parameters for the proximal imidazole in myoglobin-azide, -cyanide, and -mercaptoethanol complexes by electron spin echo envelope modulation spectroscopy.

    PubMed

    Magliozzo, R S; Peisach, J

    1993-08-24

    Electron spin echo envelope modulation (ESEEM) spectroscopy and computer simulation of spectra has been used to evaluate the nitrogen nuclear hyperfine and quadrupole coupling parameters for the proximal imidazole nitrogen directly coordinated to iron in three low-spin heme complexes, myoglobin-azide, -cyanide, and -mercaptoethanol (MbN3, MbCN, and MbRS). The variability in the weak electron-nuclear coupling parameters reveals the electronic flexibility within the heme group that depends on properties of the exogenous ligands. For example, the isotropic component of the nitrogen nuclear hyperfine coupling ranges from 4.4 MHz for MbN3 to 2.2 MHz for both MbCN and MbRS. The weaker coupling in MbCN and MbRS is taken as evidence for delocalization of unpaired electron spin from iron into the exogenous anionic ligands. The value of e2Qq, the nuclear quadrupole coupling constant for the axial imidazole nitrogen in MbCN and MbRS, was 2.5 MHz but was significantly larger, 3.2 MHz, in MbN3. This large value is considered evidence for a weakened sigma bond between the proximal imidazole and ferric iron in this form, and for a feature contributing to the origin of the high spin-low spin equilibrium exhibited by MbN3 [Beetlestone, J., & George, P. (1964) Biochemistry 5, 707-714]. The ESEEM results have allowed a correlation to be made between the orientation of the g tensor axes, the orientation of the p-pi orbital of the proximal imidazole nitrogen, and sigma- and pi-bonding features of the axial ligands. Furthermore, the proximal imidazole is suggested to act as a pi-acceptor in low-spin heme complexes in order to support strong sigma electron donation from the lone pair orbital to iron. An evaluation of the nitrogen nuclear hyperfine coupling parameters for the porphyrin pyrrole sites in MbRS reveals a large inequivalence in isotropic components consistent with an orientation of rhombic axes (and g tensor axes) that eclipses the Fe-Npyrrole vector directions. PMID:8395204

  14. Fock-space multireference coupled-cluster calculations of the hyperfine structure of isoelectronic {sup 33}S{sup -} and {sup 35,37}Cl

    SciTech Connect

    Das, Madhulita; Chaudhuri, Rajat K.; Chattopadhyay, Sudip; Mahapatra, Uttam Sinha

    2011-10-15

    Due to its flexibility and possible systematic improvement, the Fock-space (FS) multireference coupled-cluster (MRCC) method remains a very important tool for the computation of energy differences of spectroscopic interest. In the present work, the FS MRCC method for the electron detachment process has been applied to determine the magnetic hyperfine constant A{sub J} and nuclear quadrupole moments Q (related to electric hyperfine constant B{sub J}) for the lowest multiplets of {sup 33}S{sup -}, {sup 35}Cl, and {sup 37}Cl with Dirac-Fock orbitals. In addition, we also report {sup 2}P{sub 3/2}([Ne]3s{sup 2}3p{sup 5}) {yields} {sup 2}P{sub 1/2}([Ne]3s{sup 2}3p{sup 5}) magnetic dipole transition matrix element and electron affinity of {sup 35}Cl (i.e., ionization energy of Cl{sup -}). Calculated properties are in very good agreement with the available new standard or reference values.

  15. Enhanced NMR relaxation of Tomonaga-Luttinger liquids and the magnitude of the carbon hyperfine coupling in single-wall carbon nanotubes.

    PubMed

    Kiss, A; Pályi, A; Ihara, Y; Wzietek, P; Simon, P; Alloul, H; Zólyomi, V; Koltai, J; Kürti, J; Dóra, B; Simon, F

    2011-10-28

    Recent transport measurements [Churchill et al. Nature Phys. 5, 321 (2009)] found a surprisingly large, 2-3 orders of magnitude larger than usual (13)C hyperfine coupling (HFC) in (13)C enriched single-wall carbon nanotubes. We formulate the theory of the nuclear relaxation time in the framework of the Tomonaga-Luttinger liquid theory to enable the determination of the HFC from recent data by Ihara et al. [Europhys. Lett. 90, 17,004 (2010)]. Though we find that 1/T(1) is orders of magnitude enhanced with respect to a Fermi-liquid behavior, the HFC has its usual, small value. Then, we reexamine the theoretical description used to extract the HFC from transport experiments and show that similar features could be obtained with HFC-independent system parameters. PMID:22107670

  16. Relativistic unitary coupled-cluster study of the electric quadrupole moment and magnetic dipole hyperfine constants of {sup 199}Hg{sup +}

    SciTech Connect

    Sur, Chiranjib; Chaudhuri, Rajat K.

    2007-09-15

    Searching for an accurate optical clock which can serve as a better time standard than the present-day atomic clock is highly demanding from several areas of science and technology. Several attempts have been made to build more accurate clocks with different ion species. In this paper, we discuss the electric quadrupole and hyperfine shifts in the 5d{sup 9}6s{sup 2} {sup 2}D{sub 5/2}(F=0,m{sub F}=0){r_reversible}5d{sup 10}6s {sup 2}S{sub 1/2}(F=2,m{sub F}=0) clock transition in {sup 199}Hg{sup +}, one of the most promising candidates for next-generation optical clocks. We have applied Fock-space unitary coupled-cluster theory to study the electric quadrupole moment of the 5d{sup 9}6s{sup 2} {sup 2}D{sub 5/2} state and magnetic dipole hyperfine constants of 5d{sup 9}6s{sup 2} {sup 2}D{sub 3/2,5/2} and 5d{sup 10}6s{sup 1} {sup 2}S{sub 1/2} states, respectively, of {sup 199}Hg{sup +}. We have also compared our results with available data. To the best of our knowledge, this is the first time a variant of coupled-cluster theories has been applied to study these kinds of properties of Hg{sup +} and is the most accurate estimate of these quantities to date.

  17. Communication: Spin densities within a unitary group based spin-adapted open-shell coupled-cluster theory: Analytic evaluation of isotropic hyperfine-coupling constants for the combinatoric open-shell coupled-cluster scheme

    SciTech Connect

    Datta, Dipayan Gauss, Jürgen

    2015-07-07

    We report analytical calculations of isotropic hyperfine-coupling constants in radicals using a spin-adapted open-shell coupled-cluster theory, namely, the unitary group based combinatoric open-shell coupled-cluster (COSCC) approach within the singles and doubles approximation. A scheme for the evaluation of the one-particle spin-density matrix required in these calculations is outlined within the spin-free formulation of the COSCC approach. In this scheme, the one-particle spin-density matrix for an open-shell state with spin S and M{sub S} = + S is expressed in terms of the one- and two-particle spin-free (charge) density matrices obtained from the Lagrangian formulation that is used for calculating the analytic first derivatives of the energy. Benchmark calculations are presented for NO, NCO, CH{sub 2}CN, and two conjugated π-radicals, viz., allyl and 1-pyrrolyl in order to demonstrate the performance of the proposed scheme.

  18. Pure quantum dephasing of a solid-state electron spin qubit in a large nuclear spin bath coupled by long-range hyperfine-mediated interactions

    NASA Astrophysics Data System (ADS)

    Cywiński, Łukasz; Witzel, Wayne M.; Das Sarma, S.

    2009-06-01

    We investigate decoherence due to pure dephasing of a localized spin qubit interacting with a nuclear spin bath. Although in the limit of a very large magnetic field the only decoherence mechanism is spectral diffusion due to dipolar flip-flops of nuclear spins, with decreasing field the hyperfine-mediated interactions between the nuclear spins become important. We take advantage of their long-range nature and resum the leading terms in an 1/N expansion of the decoherence time-evolution function ( N , being the number of nuclear spins interacting appreciably with the electron spin, is large). For the case of the thermal uncorrelated bath we show that our theory is applicable down to low magnetic fields ( ˜10mT for a large dot with N=106 ) allowing for comparison with recent experiments in GaAs quantum dot spin qubits. Within this approach we calculate the free induction decay and spin echo decoherence in GaAs and InGaAs as a function of the number of the nuclei in the bath (i.e., the quantum dot size) and the magnetic field. Our theory for free induction decay in a narrowed nuclear bath is shown to agree with the exact solution for decoherence due to hyperfine-mediated interaction which can be obtained when all the nuclei-electron coupling constants are identical. For the spin echo evolution we show that the dominant decoherence process at low fields is due to interactions between nuclei having significantly different Zeeman energies (i.e., nuclei of As and two isotopes of Ga in GaAs), and we compare our results with recent measurements of spin echo signal of a single spin confined in a GaAs quantum dot. For the same set of parameters we perform calculations of decoherence under various dynamical decoupling pulse sequences and predict the effect of these sequences in low- B regime in GaAs.

  19. 51V solid-state magic angle spinning NMR spectroscopy of vanadium chloroperoxidase.

    PubMed

    Pooransingh-Margolis, Neela; Renirie, Rokus; Hasan, Zulfiqar; Wever, Ron; Vega, Alexander J; Polenova, Tatyana

    2006-04-19

    We report 51V solid-state NMR spectroscopy of the 67.5-kDa vanadium chloroperoxidase, at 14.1 T. We demonstrate that, despite the low concentration of vanadium sites in the protein (one per molecule, 1 mumol of vanadium spins in the entire sample), the spinning sideband manifold spanning the central and the satellite transitions is readily detectable. The quadrupolar and chemical shift anisotropy tensors have been determined by numerical simulations of the spinning sideband envelopes and the line shapes of the individual spinning sidebands corresponding to the central transition. The observed quadrupolar coupling constant C(Q) of 10.5 +/- 1.5 MHz and chemical shift anisotropy delta(sigma) of -520 +/- 13 ppm are sensitive reporters of the geometric and electronic structure of the vanadium center. Density functional theory calculations of the NMR spectroscopic observables for an extensive series of active site models indicate that the vanadate cofactor is most likely anionic with one axial hydroxo- group and an equatorial plane consisting of one hydroxo- and two oxo- groups. The work reported in this manuscript is the first example of 51V solid-state NMR spectroscopy applied to probe the vanadium center in a protein directly. This approach yields the detailed coordination environment of the metal unavailable from other experimental measurements and is expected to be generally applicable for studies of diamagnetic vanadium sites in metalloproteins. PMID:16608356

  20. Proton, muon and ¹³C hyperfine coupling constants of C₆₀X and C₇₀X (X = H, Mu).

    PubMed

    Brodovitch, Jean-Claude; Addison-Jones, Brenda; Ghandi, Khashayar; McKenzie, Iain; Percival, Paul W

    2015-01-21

    The reaction of H atoms with fullerene C70 has been investigated by identifying the radical products formed by addition of the atom muonium (Mu) to the fullerene in solution. Four of the five possible radical isomers of C70Mu were detected by avoided level-crossing resonance (μLCR) spectroscopy, using a dilute solution of enriched (13)C70 in decalin. DFT calculations were used to predict muon and (13)C isotropic hyperfine constants as an aid to assigning the observed μLCR signals. Computational methods were benchmarked against previously published experimental data for (13)C60Mu in solution. Analysis of the μLCR spectrum resulted in the first experimental determination of (13)C hyperfine constants in either C70Mu or C70H. The large number of values confirms predictions that the four radical isomers have extended distributions of unpaired electron spin. PMID:25460845

  1. Spin-torsion effects in the hyperfine structure of methanol

    SciTech Connect

    Coudert, L. H. Gutlé, C.; Huet, T. R.; Grabow, J.-U.; Levshakov, S. A.

    2015-07-28

    The magnetic hyperfine structure of the non-rigid methanol molecule is investigated experimentally and theoretically. 12 hyperfine patterns are recorded using molecular beam microwave spectrometers. These patterns, along with previously recorded ones, are analyzed in an attempt to evidence the effects of the magnetic spin-torsion coupling due to the large amplitude internal rotation of the methyl group [J. E. M. Heuvel and A. Dymanus, J. Mol. Spectrosc. 47, 363 (1973)]. The theoretical approach setup to analyze the observed data accounts for this spin-torsion in addition to the familiar magnetic spin-rotation and spin-spin interactions. The theoretical approach relies on symmetry considerations to build a hyperfine coupling Hamiltonian and spin-rotation-torsion wavefunctions compatible with the Pauli exclusion principle. Although all experimental hyperfine patterns are not fully resolved, the line position analysis yields values for several parameters including one describing the spin-torsion coupling.

  2. Hyperfine structure parametrisation in Maple

    NASA Astrophysics Data System (ADS)

    Gaigalas, G.; Scharf, O.; Fritzsche, S.

    2006-02-01

    : All computers with a license of the computer algebra package MAPLE Installations: University of Kassel (Germany) Operating systems under which the program has been tested: Linux 9.0 Program language used:MAPLE, Release 7, 8 and 9 Memory required to execute with typical data: 5 MB No. of lines in distributed program, including test data, etc.: 34 300 No. of bytes in distributed program, including test data, etc.: 954 196 Distribution format: tar.gz Nature of the physical problem: Atomic state functions of an many configuration many electron atom with several open shells are defined by a number of quantum numbers, by their coupling and selection rules such as the Pauli exclusion principal or parity conservation. The matrix elements of any one-particle operator acting on these wavefunctions can be analytically integrated up to the radial part [G. Gaigalas, O. Scharf, S. Fritzsche, Central European J. Phys. 2 (2004) 720]. The decoupling of the interacting electrons is general, the obtained submatrix element holds all the peculiarities of the operator in question. These so-called submatrix elements are the key to do hyperfine structure calculations. The interaction between the electrons and the atomic nucleus leads to an additional splitting of the fine structure lines, the hyperfine structure. The leading components are the magnetic dipole interaction defining the so-called A factor and the electric quadrupole interaction, defining the so-called B factor. They express the energetic splitting of the spectral lines. Moreover, they are obtained directly by experiments and can be calculated theoretically in an ab initio approach. A semiempirical approach allows the fitting of the radial parts of the wavefunction to the experimentally obtained A and B factors. Method of solution: Extending the existing csf_LS() and asf_LS() to several open shells and implementing a data structure level_LS() for the fine structure level, the atomic environment is defined in MAPLE. It is used in

  3. MODELING MOLECULAR HYPERFINE LINE EMISSION

    SciTech Connect

    Keto, Eric; Rybicki, George

    2010-06-20

    In this paper, we discuss two approximate methods previously suggested for modeling hyperfine spectral line emission for molecules whose collisional transition rates between hyperfine levels are unknown. Hyperfine structure is seen in the rotational spectra of many commonly observed molecules such as HCN, HNC, NH{sub 3}, N{sub 2}H{sup +}, and C{sup 17}O. The intensities of these spectral lines can be modeled by numerical techniques such as {Lambda}-iteration that alternately solve the equations of statistical equilibrium and the equation of radiative transfer. However, these calculations require knowledge of both the radiative and collisional rates for all transitions. For most commonly observed radio frequency spectral lines, only the net collisional rates between rotational levels are known. For such cases, two approximate methods have been suggested. The first method, hyperfine statistical equilibrium, distributes the hyperfine level populations according to their statistical weight, but allows the population of the rotational states to depart from local thermal equilibrium (LTE). The second method, the proportional method, approximates the collision rates between the hyperfine levels as fractions of the net rotational rates apportioned according to the statistical degeneracy of the final hyperfine levels. The second method is able to model non-LTE hyperfine emission. We compare simulations of N{sub 2}H{sup +} hyperfine lines made with approximate and more exact rates and find that satisfactory results are obtained.

  4. Magnetic ordering of hyperfine-coupled nuclear and 4f-electron moments in the clathrate compound Pr3Pd20Ge6

    NASA Astrophysics Data System (ADS)

    Iwakami, O.; Namisashi, Y.; Abe, S.; Matsumoto, K.; Ano, G.; Akatsu, M.; Mitsumoto, K.; Nemoto, Y.; Takeda, N.; Goto, T.; Kitazawa, H.

    2014-09-01

    Complex ac susceptibility, χ =χ'-iχ'', measurements of the clathrate compound Pr3Pd20Ge6 were performed in static fields up to 10 mT for H ∥[001] and at temperatures down to 500 μK. Praseodymium (Pr) nuclear magnetic moments at the 8c site, where quadrupole moments of 4f electrons order at TQ1=250 mK, were found to order antiferromagnetically at 9 mK, as shown by a peak in χ' and a substantial increase in thermal relaxation time. The large enhancement factor (1+K8c) obtained by calculation of the hyperfine-enhanced nuclear susceptibility of Pr at the 8c site accounts for the high transition temperature of Pr nuclear magnetic moments and the large χ' below 30 mK. From analysis of the crystalline electric field and the mean-field approximation, we conclude that a χ peak at 77 mK can be ascribed to an antiferromagnetic ordering of magnetic moments of 4f electrons at the 4a site. We found that nuclear and f-electron moments order separately on two sublattices in this compound. The temperature and magnetic field dependence of χ' and χ'' between 30 and 60 mK are discussed in terms of dissipation phenomena.

  5. DFT analysis of g and 13C hyperfine coupling tensors for model Ni(I)(CO)(n)L(m) (n = 1-4, L = H2O, OH-) complexes epitomizing surface nickel(I) carbonyls.

    PubMed

    Pietrzyk, Piotr; Podolska, Katarzyna; Sojka, Zbigniew

    2008-11-27

    Relativistic calculations within the spin-orbit mean-field (SOMF) approximation, the zero-order regular approximation (ZORA), and the scalar relativistic method based on the Pauli Hamiltonian were performed for the prediction and interpretation of the electronic g tensor and (13)C hyperfine tensor for a set of model polycarbonyl nickel(I) complexes with aqua or hydroxy coligands. They exhibit extensive similarities with heterogeneous [Ni(I)(CO)(n)]-surface complexes produced upon adsorption of carbon monoxide on Ni(I) ions grafted on silica or inside the zeolite channels. Benchmark calculations showing the influence of the exchange-correlation functional on the g tensor were carried out for well-defined nickel(I) complexes of known structure. On this basis, the SOMF-B3LYP scheme was chosen for calculations of the g tensor, and the obtained results were in satisfactory agreement with literature EPR data found for the [Ni(I)(CO)(n)]/SiO(2) system. The calculated g and A((13)C) tensors allowed polycarbonyl complexes of various stereochemistries to be distinguished. The nature of the Deltag(ii) shifts was assessed in terms of the molecular orbital contributions due to the magnetic-field-induced couplings and their structure sensitivity. The noncoincidence of g and (13)C hyperfine principal axes and their orientation with respect to the molecular framework was also examined. The ability of DFT calculations to follow consistently variations of the EPR parameters induced by stereochemical changes around the Ni(I) center provides an invaluable reference for the interpretation of experimental results. PMID:18986126

  6. Model for the hyperfine structure of electronically excited KCs molecules

    NASA Astrophysics Data System (ADS)

    Orbán, A.; Vexiau, R.; Krieglsteiner, O.; Nägerl, H.-C.; Dulieu, O.; Crubellier, A.; Bouloufa-Maafa, N.

    2015-09-01

    A model for determining the hyperfine structure of the excited electronic states of diatomic bialkali heteronuclear molecules is formulated from the atomic hyperfine interactions and is applied to the case of bosonic 39KCs and fermionic 40KCs molecules. The hyperfine structure of the potential-energy curves of the states correlated to the K (4 s 2S1 /2) +Cs (6 p 2P1 /2 ,3 /2) dissociation limits is described in terms of different coupling schemes depending on the internuclear distance R . These results provide a step in the calculation of the hyperfine structure of rovibrational levels of these excited molecular states in the perspective of the identification of efficient paths for creating ultracold ground-state KCs molecules.

  7. Hyperfine interaction in hydrogenated graphene

    NASA Astrophysics Data System (ADS)

    Garcia, Noel; Melle, Manuel; Fernandez-Rossier, Joaquin

    We study the hyperfine interaction of Hydrogen chemisorbed in graphene nanostructures with a gap in their spectrum, such as islands and ribbons. Chemisorption of Hydrogen on graphene results in a bound in-gap state that hosts a single electron localized around the adatom. Using both density functional theory and a four-orbital tight-binding model we study the hyperfine interaction between the hydrogen nuclear spin and the conduction electrons in graphene. We find that the strength of the hyperfine interaction decreases for larger nanostructures for which the energy gap is smaller. We then compare the results of the hyperfine interaction for large nanostructures with those of graphene 2D crystal with a periodic arrangement of chemisorbed Hydrogen atoms, obtaining very similar results. The magnitude of the hyperfine interaction is about 150 MHz, in line with that of Si:P. We acknowledge financial support by Marie-Curie-ITN 607904-SPINOGRAPH.

  8. Elastic scattering of 9Be+51V near the Coulomb barrier

    NASA Astrophysics Data System (ADS)

    Morales-Rivera, J. C.; Martinez-Quiroz, E.; Belyaeva, T. L.; Aguilera, E. F.; Lizcano, D.; Amador-Valenzuela, P.

    2016-05-01

    Elastic scattering angular distributions for the 9Be+51V system were measured at three near Coulomb barrier energies, Elab = 16.35, 17.44 and 18.53 MeV. The data were analyzed by using a Semimicroscopic Optical Model. This combines a microscopic calculation of the mean-field double folding potential and a phenomenological construction of the dynamical polarization potential. The calculations reproduced the data very well and the total reaction cross sections were also calculated.

  9. Computational and ESR studies of electron attachment to decafluorocyclopentane, octafluorocyclobutane, and hexafluorocyclopropane: electron affinities of the molecules and the structures of their stable negative ions as determined from 13C and 19F hyperfine coupling constants.

    PubMed

    ElSohly, Adel M; Tschumper, Gregory S; Crocombe, Richard A; Wang, Jih Tzong; Williams, Ffrancon

    2005-08-01

    High-resolution ESR spectra of the ground-state negative ions of hexafluorocyclopropane (c-C3F6*-), octafluorocyclobutane (c-C4F8*-), and decafluorocyclopentane (c-C5F10*-) are reported and their isotropic 19F hyperfine coupling constants (hfcc) of 198.6 +/- 0.4 G, 147.6 +/- 0.4 G, and 117.9 +/- 0.4 G, respectively, are in inverse ratio to the total number of fluorine atoms per anion. Together with the small value of 5.2 +/- 0.4 G determined for the isotropic 13C hfcc of c-C4F8*-, these results indicate that in each case the singly occupied molecular orbital (SOMO) is delocalized over the equivalent fluorines and possesses a nodal plane through the carbon atoms of a time-averaged D(nh) structure. A series of quantum chemical computations were carried out to further characterize these anions and their neutral counterparts. Both the B3LYP density functional and second-order Møller-Plesset perturbation theory (MP2) indicate that c-C3F6*- adopts a D(3h) geometry and a (2)A2'' ground electronic state, that c-C4F8*- adopts a D(4h) geometry and a (2)A2u ground electronic state, and that c-C5F10*- adopts a C(s) structure and a (2)A' electronic state. Moreover, the 19F hyperfine coupling constants computed with the MP2 method and a high quality triple-zeta basis set are within 1% of the experimental values. Also, the values computed for the 13C hfcc of c-C4F8*- are consistent with the experimental value of 5.2 G. Therefore, in keeping with the ESR results, these negative ions derived from first-row elements can be characterized as pi* species. In addition, the hypervalency of these perfluorocycloalkane radical anions has been clarified. PMID:16045345

  10. Magnetic Hyperfine Fields in Lu_2 V_2 O_7 : A Model Approach

    NASA Astrophysics Data System (ADS)

    Agzamova, Polina; Nikiforov, Anatoliy; Nazipov, Dmitriy

    2016-02-01

    We report a theoretical approach to the investigation of the magnetic hyperfine interaction on the ^{51} V nucleus in Lu_2 V_2 O_7 with the view of understanding the orbital ordering pattern in this compound. First, we have evaluated the vanadium 3d^1 -level splitting (Δ ) under the crystal field with the D _{3d} -symmetry using the point charges approximation. Second, we have calculated the exchange interaction constant (J) using the ab initio approach. It is shown that the crystal field energy is much stronger than the exchange interaction one and hence the orbital liquid state cannot occur in Lu_2 V_2 O_7 . Finally we have analyzed the magnetic hyperfine field affecting the vanadium nucleus leaning upon these results.

  11. Reaction of vanadate with aquatic humic substances: An ESR and {sup 51}V NMR study

    SciTech Connect

    Lu, Xi.; Johnson, W.D.; Hook, J.

    1998-08-01

    Electron spin resonance (ESR) spectroscopy and {sup 51}V nuclear magnetic resonance (NMR) spectroscopy have been used to study the interaction of vanadate with aqueous solutions of humic substances (HS) at different pH values and at different concentrations. Under acidic pH conditions, ESR spectra show that humic substances reduce vanadium(V) to vanadium(IV) without further reduction to vanadium(III). The reduced vanadium(IV) ion is bound to oxygen donor atoms, probably at carboxylic acid sites in the humic substances. {sup 51}V NMR spectra show that the VO{sub 2}{sup +} cation is immediately reduced and that the decavanadate cation decomposes to the VO{sub 2}{sup +} cation prior to reduction. The overall rate of reduction depends on both concentration and pH. There is no reduction above pH 6, which suggests that the standard reduction potential of humic substances is about +0.65 V. Near pH 7, vanadate is stabilized by binding to humic substances. As the concentration of humic substances increases, the total vanadium NMR signal intensity decreases. This is due to the quadrupolar nature of the {sup 51}V nucleus that, when bound to humic substances, is invisible in NMR measurements. Quantitative models applied to intensity changes show that the vanadate monomer forms HS0V(V) complexes. The formation equilibrium constant is estimated to be 108 M{sup {minus}1}. At pH above 9, NMR signals appear at {minus}623.6 and at {minus}763.2 ppm when humic substances are added to vanadate solution. The intensities of the signals increase with increasing pH and with increasing concentration of humic substances. These signals appear to be associated with peroxyvanadate anions, which are not bound to humic substances.

  12. Analysis of hyperfine structure in photoassociation spectra

    NASA Astrophysics Data System (ADS)

    Bergeman, T.

    2008-05-01

    The low Doppler width in photoassociation spectra from cold atoms makes hyperfine structure clearly visible, especially with heavier alkali atoms. Recently the focus has been on photoassociation to weakly bound dimers [1,2]. However there are also useful data on somewhat more deeply bound levels [2] for which a different coupling scheme is appropriate. Following [3], we use a F = J + I representation, and develop a transformation between this and the usual case e representation which applies at asymptotically large internuclear distance. We hope to model and assign hyperfine structure in φ = 1 states, using appropriate ground and excited state wavefunctions. To obtain eigenvalues from very large DVR matrices, we use a ``stepwise diagonalization'' procedure, which appears to be more efficient than standard sparse matrix methods. [1] E. Tiesinga et al. PRA 71, 052703 (2005); K. M. Jones et al, RMP 78, 483 (2006). [2] Data on Rb2 from J. Qi, D. Wang, Y. Huang, H. Pechkis, E. Eyler, P. Gould, W. C. Stwalley, C. C. Tsai and D.J. Heinzen; Data on RbCs from A. J. Kerman, J. M. Sage, S. Sainis and D. DeMille. [3] B. Gao, PRA 54, 2022 (1996).

  13. Measurement of transverse hyperfine interaction by forbidden transitions

    NASA Astrophysics Data System (ADS)

    Chen, Mo; Hirose, Masashi; Cappellaro, Paola

    2015-07-01

    Precise characterization of a system's Hamiltonian is crucial to its high-fidelity control that would enable many quantum technologies, ranging from quantum computation to communication and sensing. In particular, nonsecular parts of the Hamiltonian are usually more difficult to characterize, even if they can give rise to subtle but non-negligible effects. Here we present a strategy for the precise estimation of the transverse hyperfine coupling between an electronic and a nuclear spin, exploiting effects due to nominally forbidden transitions during the Rabi nutation of the nuclear spin. We applied the method to precisely determine the transverse coupling between a nitrogen-vacancy center electronic spin and its nitrogen nuclear spin. In addition, we show how this transverse hyperfine coupling, which has been often neglected in experiments, is crucial to achieving large enhancements of the nuclear Rabi nutation rate.

  14. Theoretical and electron paramagnetic resonance studies of hyperfine interaction in nitrogen doped 4H and 6H SiC

    SciTech Connect

    Szász, K.; Gali, A.

    2014-02-21

    Motivated by recent experimental findings on the hyperfine signal of nitrogen donor (N{sub C}) in 4 H and 6 H SiC, we calculate the hyperfine tensors within the framework of density functional theory. We find that there is negligible hyperfine coupling with {sup 29}Si isotopes when N{sub C} resides at h site both in 4 H and 6 H SiC. We observe measurable hyperfine coupling to a single {sup 29}Si at k site in 4 H SiC and k{sub 1} site in 6 H SiC. Our calculations unravel that such {sup 29}Si hyperfine coupling does not occur at k{sub 2} site in 6 H SiC. Our findings are well corroborated by our new electron paramagnetic resonance studies in nitrogen doped 6 H SiC.

  15. Deuterium hyperfine structure in interstellar C3HD

    NASA Technical Reports Server (NTRS)

    Bell, M. B.; Watson, J. K.; Feldman, P. A.; Matthews, H. E.; Madden, S. C.; Irvine, W. M.

    1987-01-01

    The deuterium nuclear quadrupole hyperfine structure of the transition 1(10)-1(01) of the ring molecule cyclopropenylidene-d1 (C3HD) has been observed in emission from interstellar molecular clouds. The narrowest linewidths (approximately 7 kHz) so far observed are in the cloud L1498. The derived D coupling constants Xzz = 186.9(1.4) kHz, eta=0.063(18) agree well with correlations based on other molecules.

  16. Hyperfine interaction mediated electric-dipole spin resonance: the role of frequency modulation

    NASA Astrophysics Data System (ADS)

    Li, Rui

    2016-05-01

    The electron spin in a semiconductor quantum dot can be coherently controlled by an external electric field, an effect called electric-dipole spin resonance (EDSR). Several mechanisms can give rise to the EDSR effect, among which there is a hyperfine mechanism, where the spin-electric coupling is mediated by the electron–nucleus hyperfine interaction. Here, we investigate the influence of frequency modulation (FM) on the spin-flip efficiency. Our results reveal that FM plays an important role in the hyperfine mechanism. Without FM, the electric field almost cannot flip the electron spin the spin-flip probability is only about 20%. While under FM, the spin-flip probability can be improved to approximately 70%. In particular, we find that the modulation amplitude has a lower bound, which is related to the width of the fluctuated hyperfine field.

  17. Chlorine Nuclear Quadrupole Hyperfine Structure in the Vinyl - Chloride Complex

    NASA Astrophysics Data System (ADS)

    Leung, Helen O.; Marshall, Mark D.; Messinger, Joseph P.

    2015-06-01

    The microwave spectrum of the vinyl chloride--hydrogen chloride complex, presented at last year's symposium, is greatly complicated by the presence of two chlorine nuclei as well as an observed, but not fully explained tunneling motion. Indeed, although it was possible at that time to demonstrate conclusively that the complex is nonplanar, the chlorine nuclear quadrupole hyperfine splitting in the rotational spectrum resisted analysis. With higher resolution, Balle-Flygare Fourier transform microwave spectra, the hyperfine structure has been more fully resolved, but appears to be perturbed for some rotational transitions. It appears that knowledge of the quadrupole coupling constants will provide essential information regarding the structure of the complex, specifically the location of the hydrogen atom in HCl. Our progress towards obtaining values for these constants will be presented.

  18. Effective Hyperfine-structure Functions of Ammonia

    NASA Astrophysics Data System (ADS)

    Augustovičová, L.; Soldán, P.; Špirko, V.

    2016-06-01

    The hyperfine structure of the rotation-inversion (v 2 = 0+, 0‑, 1+, 1‑) states of the 14NH3 and 15NH3 ammonia isotopomers is rationalized in terms of effective (ro-inversional) hyperfine-structure (hfs) functions. These are determined by fitting to available experimental data using the Hougen’s effective hyperfine-structure Hamiltonian within the framework of the non-rigid inverter theory. Involving only a moderate number of mass independent fitting parameters, the fitted hfs functions provide a fairly close reproduction of a large majority of available experimental data, thus evidencing adequacy of these functions for reliable prediction. In future experiments, this may help us derive spectroscopic constants of observed inversion and rotation-inversion transitions deperturbed from hyperfine effects. The deperturbed band centers of ammonia come to the forefront of fundamental physics especially as the probes of a variable proton-to-electron mass ratio.

  19. Numerical simulations of hyperfine transitions of antihydrogen

    NASA Astrophysics Data System (ADS)

    Kolbinger, B.; Capon, A.; Diermaier, M.; Lehner, S.; Malbrunot, C.; Massiczek, O.; Sauerzopf, C.; Simon, M. C.; Widmann, E.

    2015-08-01

    One of the ASACUSA (Atomic Spectroscopy And Collisions Using Slow Antiprotons) collaboration's goals is the measurement of the ground state hyperfine transition frequency in antihydrogen, the antimatter counterpart of one of the best known systems in physics. This high precision experiment yields a sensitive test of the fundamental symmetry of CPT. Numerical simulations of hyperfine transitions of antihydrogen atoms have been performed providing information on the required antihydrogen events and the achievable precision.

  20. Quantum versus classical hyperfine-induced dynamics in a quantum dota)

    NASA Astrophysics Data System (ADS)

    Coish, W. A.; Loss, Daniel; Yuzbashyan, E. A.; Altshuler, B. L.

    2007-04-01

    In this article we analyze spin dynamics for electrons confined to semiconductor quantum dots due to the contact hyperfine interaction. We compare mean-field (classical) evolution of an electron spin in the presence of a nuclear field with the exact quantum evolution for the special case of uniform hyperfine coupling constants. We find that (in this special case) the zero-magnetic-field dynamics due to the mean-field approximation and quantum evolution are similar. However, in a finite magnetic field, the quantum and classical solutions agree only up to a certain time scale t <τc, after which they differ markedly.

  1. Temperature-dependent hyperfine interactions at 111Cd-C complex in germanium

    NASA Astrophysics Data System (ADS)

    Mola, Genene Tessema

    2013-09-01

    The temperature dependent nuclear hyperfine interaction of 111Cd-carbon complex in germanium has been studied using the perturbed γ- γ angular correlation (PAC) method. The parameters of the hyperfine interaction representing substitutional carbon-cadmium complex in germanium ( ν Q1=207(1) MHz ( η=0.16)) shows dependence on temperature. The formation and thermal stability of the complex has been reported by the same author earlier. It was found in this study that the quadrupole coupling constant of the interaction increases at sample temperature below 293 K. The results are encouraging toward better understanding of the complex in the host matrix.

  2. Dynamic polarizabilities and hyperfine-structure constants for Sc2 +

    NASA Astrophysics Data System (ADS)

    Dutta, Narendra Nath; Roy, Sourav; Deshmukh, P. C.

    2015-11-01

    In this work, we calculate dynamic polarizabilities and hyperfine-structure A and B constants of a few low-lying states for Sc2 +. The sum-over-states technique is applied to calculate the polarizabilities of the 3 d 2D3 /2 ,3 d 2D5 /2 , and 4 s 2S1 /2 states. The most important and correlation sensitive part of the sum is calculated using a highly correlated relativistic coupled-cluster theory. The remaining part of the sum is calculated using a lower-order many-body perturbation theory and the Dirac-Fock theory. Present dynamic polarizabilities are important to investigate the Stark shifts in the 4 s 2S1 /2 - 3 d 2D5 /2 and 4 s 2S1 /2 - 3 d 2D3 /2 clock transitions of Sc2 +. Magic wavelengths for zero Stark shifts corresponding to these transitions are found in the vacuum-ultraviolet region. The coupled-cluster theory is used to estimate the hyperfine A and B constants with a very high accuracy.

  3. Hyperfine Stark effect of shallow donors in silicon

    NASA Astrophysics Data System (ADS)

    Pica, Giuseppe; Wolfowicz, Gary; Urdampilleta, Matias; Thewalt, Mike L. W.; Riemann, Helge; Abrosimov, Nikolai V.; Becker, Peter; Pohl, Hans-Joachim; Morton, John J. L.; Bhatt, R. N.; Lyon, S. A.; Lovett, Brendon W.

    2014-11-01

    We present a complete theoretical treatment of Stark effects in bulk doped silicon, whose predictions are supported by experimental measurements. A multivalley effective mass theory, dealing nonperturbatively with valley-orbit interactions induced by a donor-dependent central cell potential, allows us to obtain a very reliable picture of the donor wave function within a relatively simple framework. Variational optimization of the 1 s donor binding energies calculated with a new trial wave function, in a pseudopotential with two fitting parameters, allows an accurate match of the experimentally determined donor energy levels, while the correct limiting behavior for the electronic density, both close to and far from each impurity nucleus, is captured by fitting the measured contact hyperfine coupling between the donor nuclear and electron spin. We go on to include an external uniform electric field in order to model Stark physics: with no extra ad hoc parameters, variational minimization of the complete donor ground energy allows a quantitative description of the field-induced reduction of electronic density at each impurity nucleus. Detailed comparisons with experimental values for the shifts of the contact hyperfine coupling reveal very close agreement for all the donors measured (P, As, Sb, and Bi). Finally, we estimate field ionization thresholds for the donor ground states, thus setting upper limits to the gate manipulation times for single qubit operations in Kane-like architectures: the Si:Bi system is shown to allow for A gates as fast as ≈10 MHz.

  4. Observation of hyperfine interaction in photoassociation spectra of ultracold RbYb

    NASA Astrophysics Data System (ADS)

    Bruni, C.; Görlitz, A.

    2016-08-01

    We report on the creation of ultracold heteronuclear and electronically excited Rb*Yb molecules in a hybrid conservative trap by photoassociation of ultracold 87Rb and 176Yb. The molecules are formed below the Rb5 p 1(1/2 2P)+Yb6 s 2(S10) dissociation limit and the resonances are detected using trap-loss spectroscopy. By addressing vibrational levels with binding energies down to EB=-h ×2.2 THz , we study the change in hyperfine coupling of the diatomic molecule as a function of internuclear separation. We observe a decreasing hyperfine splitting for more tightly bound excited molecular states where the hyperfine splitting is reduced by more than 30 % compared to the atomic value for 87Rb.

  5. Local Electric Properties of β-Ag0.33V2O5 Studied by 51V NMR

    NASA Astrophysics Data System (ADS)

    Hisada, Akihiko; Fujiwara, Naoki; Yamauchi, Touru; Ueda, Yutaka

    2009-09-01

    The local electric properties of β-Ag0.33V2O5, a pressure-induced superconductor, were studied at ambient pressure using a nuclear magnetic resonance (NMR) technique. Three crystallographically inequivalent Vi sites (i=1, 2, and 3) were identified from 51V-NMR spectra. We determined the principal axes of the electric-field-gradient (EFG) tensor, electric quadrupole frequency, asymmetric parameter, and Knight shift for each Vi site in the metallic phase and the subsequent charge-ordering (CO) phase at low temperatures. The results suggest that the electric properties for the V1 sites are similar to those for the V3 sites, whereas those for the V2 sites are different from those for the V1 and V3 sites. The peculiarity in the metallic phase reflects the electric properties in the CO phase and is attributable to the diagonal structure of the Vi orbitals.

  6. HfS: Hyperfine Structure fitting tool

    NASA Astrophysics Data System (ADS)

    Estalella, Robert

    2016-07-01

    HfS fits the hyperfine structure of spectral lines, with multiple velocity components. The HfS_nh3 procedures included in HfS fit simultaneously the hyperfine structure of the NH3 (J,K)= (1,1) and (2,2) inversion transitions, and perform a standard analysis to derive the NH3 column density, rotational temperature Trot, and kinetic temperature Tk. HfS uses a Monte Carlo approach for fitting the line parameters, with special attention to the derivation of the parameter uncertainties. HfS includes procedures that make use of parallel computing for fitting spectra from a data cube.

  7. Hyperfine field and magnetic structure in the B phase of CeCoIn5

    SciTech Connect

    Graf, Matthias J; Curro, Nicholas J; Young, Ben - Li; Urbano, Ricardo R

    2009-01-01

    We re-analyze Nuclear Magnetic Resonance (NMR) spectra observed at low temperatures and high magnetic fields in the field-induced B-phase of CeCoIn{sub 5}. The NMR spectra are consistent with incommensurate antiferromagnetic order of the Ce magnetic moments. However, we find that the spectra of the In(2) sites depend critically on the direction of the ordered moments, the ordering wavevector and the symmetry of the hyperfine coupling to the Ce spins. Assuming isotropic hyperfine coupling, the NMR spectra observed for H {parallel} [100] are consistent with magnetic order with wavevector Q = {pi}(1+{delta}/a, 1/a, 1/c) and Ce moments ordered antiferromagnetically along the [100] direction in real space. If the hyperfine coupling has dipolar symmetry, then the NMR spectra require Ce moments along the [001] direction. The dipolar scenario is also consistent with recent neutron scattering measurements that find an ordered moment of 0.15{micro}{sub B} along [001] and Q{sub n} = {pi}(1+{delta}/a, 1+{delta}c, 1/c) with incommensuration {delta} = 0.12 for field H {parallel} [1{bar 1}0]. Using these parameters, we find that the hyperfine field is consistent with both experiments. We speculate that the B phase of CeCoIn{sub 5} represents an intrinsic phase of modulated superconductivity and antiferromagnetism that can only emerge in a highly clean system.

  8. Hyperfine meson splittings: chiral symmetry versus transverse gluon exchange

    SciTech Connect

    Felipe J. Llanes-Estrada; Stephen R. Cotanch; Adam P. Szczepaniak; Eric S. Swanson

    2004-02-01

    Meson spin splittings are examined within an effective Coulomb gauge QCD Hamiltonian incorporating chiral symmetry and a transverse hyperfine interaction necessary for heavy quarks. For light and heavy quarkonium systems the pseudoscalar-vector meson spectrum is generated by approximate BCS-RPA diagonalizations. This relativistic formulation includes both S and D waves for the vector mesons which generates a set of coupled integral equations. A smooth transition from the heavy to the light quark regime is found with chiral symmetry dominating the /pi-/rho mass difference. A good, consistent description of the observed meson spin splittings and chiral quantities, such as the quark condensate and the /pi mass, is obtained. Similar comparisons with TDA diagonalizations, which violate chiral symmetry, are deficient for light pseudoscalar mesons indicating the need to simultaneously include both chiral symmetry and a hyperfine interaction. The /eta{sub b} mass is predicted to be around 9400 MeV consistent with other theoretical expectations and above the unconfirmed 9300 MeV candidate. Finally, for comparison with lattice results, the J reliability parameter is also evaluated.

  9. Radiative transfer of HCN: interpreting observations of hyperfine anomalies

    NASA Astrophysics Data System (ADS)

    Mullins, A. M.; Loughnane, R. M.; Redman, M. P.; Wiles, B.; Guegan, N.; Barrett, J.; Keto, E. R.

    2016-07-01

    Molecules with hyperfine splitting of their rotational line spectra are useful probes of optical depth, via the relative line strengths of their hyperfine components. The hyperfine splitting is particularly advantageous in interpreting the physical conditions of the emitting gas because with a second rotational transition, both gas density and temperature can be derived. For HCN however, the relative strengths of the hyperfine lines are anomalous. They appear in ratios which can vary significantly from source to source, and are inconsistent with local thermodynamic equilibrium (LTE). This is the HCN hyperfine anomaly, and it prevents the use of simple LTE models of HCN emission to derive reliable optical depths. In this paper, we demonstrate how to model HCN hyperfine line emission, and derive accurate line ratios, spectral line shapes and optical depths. We show that by carrying out radiative transfer calculations over each hyperfine level individually, as opposed to summing them over each rotational level, the anomalous hyperfine emission emerges naturally. To do this requires not only accurate radiative rates between hyperfine states, but also accurate collisional rates. We investigate the effects of different sets of hyperfine collisional rates, derived via the proportional method and through direct recoupling calculations. Through an extensive parameter sweep over typical low-mass star-forming conditions, we show the HCN line ratios to be highly variable to optical depth. We also reproduce an observed effect whereby the red-blue asymmetry of the hyperfine lines (an infall signature) switches sense within a single rotational transition.

  10. Hyperfine structure of /sup 3/He

    SciTech Connect

    Druzbick, J.; Williams, H.T.

    1987-01-01

    Relativistic contribution to the hyperfine structure of /sup 3/He are reexamined in order to resolve inconsistencies in published values. The orbit-orbit and diamagnetic screening contributions are recomputed and are found to contribute less than one part per million (ppm), contrary to previous results. A new value (318 ppm compared to the perturbation result of 327 ppm) is obtained for the relativistic velocity correction using recently available relativistic Hartree-Fock wave functions. New values of the hyperfine-structure splitting of /sup 3/He in the 1S2S state and the /sup 3/He ion in the 1S and 2S states are presented. Comparison with experiment suggests that the relativistic velocity correction should be 323 ppm and the nuclear structure correction should be 184.2 ppm.

  11. Hyperfine interaction mediated electric-dipole spin resonance: The role of the frequency modulation

    NASA Astrophysics Data System (ADS)

    Li, Rui

    The electron spin in semiconductor quantum dot can be coherently controlled by an external electric field, an effect called electric-dipole spin resonance (EDSR). There are several mechanisms underlie the EDSR, among which there is a hyperfine mechanism, where the spin-electric coupling is mediated by the electron-nucleus hyperfine interaction. Here, we investigate the influence of the frequency modulation (FM) to the driving electric field on the spin-flip efficiency. Our results reveal that FM plays an important role in the hyperfine mechanism. Without FM, the electric field almost cannot flip the electron spin, the spin-flip probability is only about 20%. While under the FM, the spin-flip probability can be improved approximately to 70%. Especially, we find there is a lower bound on the modulation amplitude, which is related to the width of the hyperfine field fluctuation of the nuclear spins. This work is supported by National Natural Science Foundation of China Grant No. 11404020 and Postdoctoral Science Foundation of China Grant No. 2014M560039.

  12. Hyperfine-enhanced gyromagnetic ratio of a nuclear spin in diamond

    NASA Astrophysics Data System (ADS)

    Sangtawesin, S.; McLellan, C. A.; Myers, B. A.; Bleszynski Jayich, A. C.; Awschalom, D. D.; Petta, J. R.

    2016-08-01

    The nuclear spin gyromagnetic ratio can be enhanced by hyperfine coupling to the electronic spin. Here we show wide tunability of this enhancement on a 15N nuclear spin intrinsic to a single nitrogen-vacancy center in diamond. We perform control of the nuclear spin near the ground state level anti-crossing (GSLAC), where the enhancement of the gyromagnetic ratio from the ground state hyperfine coupling is maximized. We demonstrate a two order of magnitude enhancement of the effective nuclear gyromagnetic ratio compared to the value obtained at 500 G, a typical operating field that is suitable for nuclear spin polarization. Finally, we show that with strong enhancements, the nuclear spin ultimately suffers dephasing from the inhomogeneous broadening of the NMR transition frequency at the GSLAC.

  13. Characterization of Oxygen Bridged Manganese Model Complexes Using Multifrequency (17)O-Hyperfine EPR Spectroscopies and Density Functional Theory.

    PubMed

    Rapatskiy, Leonid; Ames, William M; Pérez-Navarro, Montserrat; Savitsky, Anton; Griese, Julia J; Weyhermüller, Thomas; Shafaat, Hannah S; Högbom, Martin; Neese, Frank; Pantazis, Dimitrios A; Cox, Nicholas

    2015-10-29

    Multifrequency pulsed EPR data are reported for a series of oxygen bridged (μ-oxo/μ-hydroxo) bimetallic manganese complexes where the oxygen is labeled with the magnetically active isotope (17)O (I = 5/2). Two synthetic complexes and two biological metallocofactors are examined: a planar bis-μ-oxo bridged complex and a bent, bis-μ-oxo-μ-carboxylato bridge complex; the dimanganese catalase, which catalyzes the dismutation of H2O2 to H2O and O2, and the recently identified manganese/iron cofactor of the R2lox protein, a homologue of the small subunit of the ribonuclotide reductase enzyme (class 1c). High field (W-band) hyperfine EPR spectroscopies are demonstrated to be ideal methods to characterize the (17)O magnetic interactions, allowing a magnetic fingerprint for the bridging oxygen ligand to be developed. It is shown that the μ-oxo bridge motif displays a small positive isotropic hyperfine coupling constant of about +5 to +7 MHz and an anisotropic/dipolar coupling of -9 MHz. In addition, protonation of the bridge is correlated with an increase of the hyperfine coupling constant. Broken symmetry density functional theory is evaluated as a predictive tool for estimating hyperfine coupling of bridging species. Experimental and theoretical results provide a framework for the characterization of the oxygen bridge in Mn metallocofactor systems, including the water oxidizing cofactor of photosystem II, allowing the substrate/solvent interface to be examined throughout its catalytic cycle. PMID:26225537

  14. Observation of nuclear quadrupole hyperfine structure in the infrared spectrum of hydrogen iodide using a tunable-diode laser

    NASA Technical Reports Server (NTRS)

    Strow, L. L.

    1980-01-01

    Nuclear quadrupole hyperfine structure has been observed in the 1-0 vibration-rotation band of hydrogen iodide with a tunable-diode laser. The measured splittings agree well with microwave measurements of the HI molecule. Evidence for a slight change in the iodine nuclear quadrupole coupling constant from the ground to first excited vibrational state in hydrogen iodide was found.

  15. Nagaoka's atomic model and hyperfine interactions.

    PubMed

    Inamura, Takashi T

    2016-01-01

    The prevailing view of Nagaoka's "Saturnian" atom is so misleading that today many people have an erroneous picture of Nagaoka's vision. They believe it to be a system involving a 'giant core' with electrons circulating just outside. Actually, though, in view of the Coulomb potential related to the atomic nucleus, Nagaoka's model is exactly the same as Rutherford's. This is true of the Bohr atom, too. To give proper credit, Nagaoka should be remembered together with Rutherford and Bohr in the history of the atomic model. It is also pointed out that Nagaoka was a pioneer of understanding hyperfine interactions in order to study nuclear structure. PMID:27063182

  16. Effect of Ancillary Ligand on Electronic Structure as Probed by 51V Solid-State NMR Spectroscopy for Vanadium-o-Dioxolene Complexes

    PubMed Central

    Goncharova-Zapata, Olga; Chatterjee, Pabitra B.; Hou, Guangjin; Quinn, Laurence L.; Li, Mingyue; Yehl, Jenna

    2013-01-01

    A series of vanadium(V) complexes with o-dioxolene (catecholato) ligands and an ancillary ligand, (N-(salicylideneaminato)ethylenediamine) (hensal), were investigated using 51V solid-state magic angle spinning NMR spectroscopy (51V MAS NMR) to assess the local environment of the vanadium(V). The solid-state 51V NMR parameters of vanadium(V) complexes with a related potentially tetradentate ancillary ligand (N-salicylidene-N′-(2-hydroxyethyl)ethylenediamine) (h2shed) were previously shown to be associated with the size of the HOMO-LUMO gap in the complex, and as such provide insights on the interaction between metal ion and ligand (P. B. Chatterjee, et al., Inorg. Chem 50 (2011) 9794). Our results show that the modification of the ancillary ligand does not impact the observed trend between complexes ranging from catechols with electron rich to electron poor substituents. However, the ancillary ligand does impact the size of the HOMO-LUMO separation in the parent complex and thus the solid-state vanadium NMR chemical shift of the unsubstituted vanadium complex. For these complexes significant changes observed in the isotropic shifts and more modest changes detected in the CQ reflect the electronic changes in the complex as the catechol is varied. However, no obvious trend was observed in the chemical shift anisotropies (δσ and ησ) with the variation in the catechol. The electronic changes in the coordination environment of the vanadium can be described using solid-state 51V NMR spectroscopy. PMID:24353476

  17. Hyperfine-induced quadrupole moments of alkali-metal-atom ground states and their implications for atomic clocks

    NASA Astrophysics Data System (ADS)

    Derevianko, Andrei

    2016-01-01

    Spherically symmetric ground states of alkali-metal atoms do not posses electric quadrupole moments. However, the hyperfine interaction between nuclear moments and atomic electrons distorts the spherical symmetry of electronic clouds and leads to nonvanishing atomic quadrupole moments. We evaluate these hyperfine-induced quadrupole moments using techniques of relativistic many-body theory and compile results for Li, Na, K, Rb, and Cs atoms. For heavy atoms we find that the hyperfine-induced quadrupole moments are strongly (two orders of magnitude) enhanced by correlation effects. We further apply the results of the calculation to microwave atomic clocks where the coupling of atomic quadrupole moments to gradients of electric fields leads to clock frequency uncertainties. We show that for 133Cs atomic clocks, the spatial gradients of electric fields must be smaller than 30 V /cm2 to guarantee fractional inaccuracies below 10-16.

  18. Hyperfine structure of hydrogenlike thallium isotopes

    SciTech Connect

    Beiersdorfer, Peter; Utter, Steven B.; Wong, Keith L.; Crespo Lopez-Urrutia, Jose R.; Britten, Jerry A.; Chen, Hui; Harris, Clifford L.; Thoe, Robert S.; Thorn, Daniel B.; Traebert, Elmar

    2001-09-01

    The hyperfine splitting of the 1s ground state of hydrogenlike Tl has been measured for the two stable isotopes using emission spectroscopy in the SuperEBIT electron-beam ion trap, giving 3858.22{+-}0.30 {angstrom} for {sup 203}Tl{sup 80+} and 3821.84{+-}0.34 {angstrom} for {sup 205}Tl{sup 80+} with a wavelength difference {Delta}{lambda}=36.38{+-}0.35 {angstrom}. This difference is consistent with estimates based on hyperfine anomaly data for neutral Tl only if finite size effects are included in the calculation. By using previously determined nuclear magnetic moments, and applying appropriate corrections for the nuclear charge distribution and radiative effects, the experimental splittings can be interpreted in terms of nuclear magnetization radii {sup 1/2}=5.83(14) fm for {sup 203}Tl and {sup 1/2}=5.89(14) fm for {sup 205}Tl. These values are 10% larger than derived from single-particle nuclear magnetization models, and are slightly larger than the corresponding charge distributions.

  19. Precision measurement of the off-diagonal hyperfine interaction

    SciTech Connect

    Gilbert, S.L.; Masterson, B.P.; Noecker, M.C.; Wieman, C.E.

    1986-10-01

    We have measured the hyperfine mixing of the 6S and 7S states of cesium using a new high-precision experimental technique. By comparing the diagonal and off-diagonal hyperfine interaction for these states, we find that a single-particle description of the states is accurate to better than 2%.

  20. Spin-dependent recombination and hyperfine interaction at deep defects

    NASA Astrophysics Data System (ADS)

    Ivchenko, E. L.; Bakaleinikov, L. A.; Kalevich, V. K.

    2015-05-01

    We present a theoretical study of optical electron-spin orientation and spin-dependent Shockley-Read-Hall recombination in the longitudinal magnetic field, taking into account the hyperfine coupling between the bound-electron spin and the nuclear spin of a deep paramagnetic center. The master rate equations for the coupled system are extended to describe the nuclear spin relaxation by using two distinct relaxation times, τn 1 and τn 2, respectively, for defect states with one and two (singlet) bound electrons. The general theory is developed for an arbitrary value of the nuclear spin I . The magnetic-field and excitation-power dependencies of the electron and nuclear spin polarizations are calculated for the value of I =1 /2 . In this particular case the nuclear effects can be taken into account by a simple replacement of the bound-electron spin relaxation time by an effective time dependent on free-electron and hole densities and free-electron spin polarization. The role of nuclear spin relaxation is visualized by isolines of the electron spin polarization on a two-dimensional graph with the axes log2(τn 1) and log2(τn 2) .

  1. Evolution of hyperfine parameters across a quantum critical point in CeRhIn5

    NASA Astrophysics Data System (ADS)

    Lin, C. H.; Shirer, K. R.; Crocker, J.; Dioguardi, A. P.; Lawson, M. M.; Bush, B. T.; Klavins, P.; Curro, N. J.

    2015-10-01

    We report nuclear magnetic resonance (NMR) data for both the In(1) and In(2) sites in the heavy-fermion material CeRhIn5 under hydrostatic pressure. The Knight shift data reveal a suppression of the hyperfine coupling to the In(1) site as a function of pressure, and the electric field gradient να α at the In(2) site exhibits a change of slope d να α/d P at Pc 1=1.75 GPa. These changes to the coupling constants reflect alterations to the electronic structure at the quantum critical point.

  2. Hyperfine interaction measurements on ceramics: PZT revisited

    NASA Astrophysics Data System (ADS)

    Guarany, Cristiano A.; Araújo, Eudes B.; Silva, Paulo R. J.; Saitovitch, Henrique

    2007-02-01

    The solid solution of PbZr 1-xTi xO 3, known as lead-zirconate titanate (PZT), was probably one of the most studied ferroelectric materials, especially due to its excellent dielectric, ferroelectric and piezoelectric properties. The highest piezoelectric coefficients of the PZT are found near the morphotropic phase boundary (MPB) (0.46⩽ x⩽0.49), between the tetragonal and rhombohedral regions of the composition-temperature phase diagram. Recently, a new monoclinic phase near the MPB was observed, which can be considered as a “bridge” between PZT's tetragonal and rhombohedral phases. This work is concerned with the study of the structural properties of the ferroelectric PZT (Zr/Ti=52/48, 53/47) by hyperfine interaction (HI) measurements obtained from experiments performed by using the nuclear spectroscopy time differential perturbed angular correlation (TDPAC) in a wide temperature range.

  3. Rotational spectra, nuclear quadrupole hyperfine tensors, and conformational structures of the mustard gas simulent 2-chloroethyl ethyl sulfide

    NASA Astrophysics Data System (ADS)

    Tubergen, M. J.; Lesarri, A.; Suenram, R. D.; Samuels, A. C.; Jensen, J. O.; Ellzy, M. W.; Lochner, J. M.

    2005-10-01

    Rotational spectra have been recorded for both the 35Cl and 37Cl isotopic forms of two structural conformations of 2-chloroethyl ethyl sulfide (CEES). The rotational constants of the 35Cl and 37Cl isotopomers were used to identify the conformational isomers. A total of 236 hyperfine transitions have been assigned for 47 rotational transitions of the 35Cl isotope of a GGT conformer, and 146 hyperfine have been assigned for 37 rotational transitions of the 37Cl isotopomer. For the second conformer, a total of 128 (110) hyperfine and 30 (28) rotational transitions have also been assigned to the 35Cl ( 37Cl) isotopes of a TGT conformation. The extensive hyperfine splitting data, measured to high resolution with a compact Fourier transform microwave spectrometer, were used to determine both the diagonal and off-diagonal elements of the 35Cl and 37Cl nuclear quadrupole coupling tensors in the inertial tensor principal axis system. The experimental rotational constant data, as well as the 35Cl and 37Cl nuclear quadrupole coupling tensors, were compared to the results from 27 optimized ab initio (HF/6-311++G ∗∗ and MP2/6-311++G ∗∗) model structures.

  4. COUPLING

    DOEpatents

    Hawke, B.C.

    1963-02-26

    This patent relates to a releasable coupling connecting a control rod to a control rod drive. This remotely operable coupling mechanism can connect two elements which are laterally and angviarly misaligned, and provides a means for sensing the locked condition of the elements. The coupling utilizes a spherical bayonet joint which is locked against rotation by a ball detent lock. (AEC)

  5. The hyperfine properties of a hydrogenated Fe/V superlattice

    NASA Astrophysics Data System (ADS)

    Elzain, M.; Al-Barwani, M.; Gismelseed, A.; Al-Rawas, A.; Yousif, A.; Widatallah, H.; Bouziane, K.; Al-Omari, I.

    2012-03-01

    We study the effect of hydrogen on the electronic, magnetic and hyperfine structures of an iron-vanadium superlattice consisting of three Fe monolayers and nine V monolayers. The contact charge density ( ρ), the contact hyperfine field (Bhf) and the electronic field gradient (EFG) at the Fe sites for different H locations and H fillings are calculated using the first principle full-potential linear-augmented-plane-wave (FP-LAPW) method. It is found that sizeable changes in the hyperfine properties are obtained only when H is in the interface region.

  6. Quantum Theory of Hyperfine Structure Transitions in Diatomic Molecules.

    ERIC Educational Resources Information Center

    Klempt, E.; And Others

    1979-01-01

    Described is an advanced undergraduate laboratory experiment in which radio-frequency transitions between molecular hyperfine structure states may be observed. Aspects of the quantum theory applied to the analysis of this physical system, are discussed. (Authors/BT)

  7. The hyperfine excitation of OH radicals by He

    NASA Astrophysics Data System (ADS)

    Marinakis, Sarantos; Kalugina, Yulia; Lique, François

    2016-04-01

    Hyperfine-resolved collisions between OH radicals and He atoms are investigated using quantum scattering calculations and the most recent ab initio potential energy surface, which explicitly takes into account the OH vibrational motion. Such collisions play an important role in astrophysics, in particular in the modelling of OH masers. The hyperfine-resolved collision cross sections are calculated for collision energies up to 2500 cm-1 from the nuclear spin free scattering S-matrices using a recoupling technique. The collisional hyperfine propensities observed are discussed. As expected, the results from our work suggest that there is a propensity for collisions with ΔF = Δj. The new OH-He hyperfine cross sections are expected to significantly help in the modelling of OH masers from current and future astronomical observations. Contribution to the Topical Issue "Atomic Cluster Collisions (7th International Symposium)", edited by Gerardo Delgado Barrio, Andrey Solov'Yov, Pablo Villarreal, Rita Prosmiti.

  8. Investigation of the Structure and Active Sites of TiO2 Nanorod Supported VOx Catalysts by High-Field and Fast-Spinning 51V MAS NMR

    SciTech Connect

    Hu, Jian Z.; Xu, Suochang; Li, Weizhen; Hu, Mary Y.; Deng, Xuchu; Dixon, David A.; Vasiliu, Monica; Craciun, Raluca; Wang, Yong; Bao, Xinhe; Peden, Charles HF

    2015-07-02

    Supported VOx/TiO2-Rod catalysts were studied by 51V MAS NMR at high field using a sample spinning rate of 55 kHz. The superior spectral resolution allows for the observation of at least five vanadate species. The assignment of these vanadate species was carried out by quantum mechanical calculations of 51V NMR chemical shifts of model V-surface structures. Methanol oxidative dehydrogenation (ODH) was used to establish the correlation between the reaction rate and the various surface V-sites. It is found that monomeric V-species dominated the catalyst at low vanadium loadings with two peaks observed at about -502 and -529 ppm. V-dimers with two bridged oxygen appeare at about -555 ppm. Vanadate dimers and polyvanadates connected by one bridged oxygen atom between two adjacent V atoms resonate at about -630 ppm. A positive correlation is found between the V-dimers related to the -555 ppm peak and the ODH rate while a better correlation is obtained by including monomeric contributions. This result indicates that surface V-dimers related to the -555 ppm peak are the major active sites for ODH reaction despite mono-V species are more catalytic active but their relative ratios are decreased dramatically at high V-loadings. Furthermore, a portion of the V-species is found invisible. In particular, the level of such invisibility increases with decreased level of V-loading, suggesting the existence of paramagnetic V-species at the surface.

  9. New experimental constraints on polarizability corrections to hydrogen hyperfine structure

    SciTech Connect

    Vahagn Nazaryan; Carl Carlson; Keith Griffioen

    2006-04-01

    We present a state-of-the-art evaluation of the polarizability corrections--the inelastic nucleon corrections--to the hydrogen ground-state hyperfine splitting using analytic fits to the most recent data. We find a value {Delta}{sub pol} = 1.3 {+-} 0.3 ppm. This is 1-2 ppm smaller than the value of {Delta}{sub pol} deduced using hyperfine splitting data and elastic nucleon corrections obtained from modern form factor fits.

  10. Theory of hyperfine anomalies in muonic atoms

    SciTech Connect

    Freeman, A.J.; Mallow, J.V.; Desclaux, J.P.; Weinert, M.

    1983-01-01

    Negative muon spin precession experiments by Yamazaki, et al. have found giant hyperfine anomalies in muonic atoms ranging from a few percent up to 36%. In order to understand their results, we present Breit interaction calculations based on atomic self-consistent unrestricted Dirac-Fock solutions which explicitly include all electrons and the negative muon. The Breit interaction results (including the relativistic correction for the bound muon g-factor), vary from near zero for ..mu../sup -/ O/N to -5% for ..mu../sup -/Pd/Rh; this latter is much larger than the calculated muonic or nuclear Bohr-Weisskopf anomalies and much smaller than the 36% measured value. For ..mu../sup -/Ni/Co we find a calculated range of results (depending on assumed electronic configurations) of -2.3 to -2.7% in excellent agreement with recent measurements of the Yamazaki group. This excellent agreement in ..mu../sup -/Ni/Co provides strong support for the earlier suggestions that the discrepancy in the case of ..mu../sup -/Pd/Rh is due to experimental factors.

  11. Searching for an Oscillating Massive Scalar Field as a Dark Matter Candidate Using Atomic Hyperfine Frequency Comparisons

    NASA Astrophysics Data System (ADS)

    Hees, A.; Guéna, J.; Abgrall, M.; Bize, S.; Wolf, P.

    2016-08-01

    We use 6 yrs of accurate hyperfine frequency comparison data of the dual rubidium and caesium cold atom fountain FO2 at LNE-SYRTE to search for a massive scalar dark matter candidate. Such a scalar field can induce harmonic variations of the fine structure constant, of the mass of fermions, and of the quantum chromodynamic mass scale, which will directly impact the rubidium/caesium hyperfine transition frequency ratio. We find no signal consistent with a scalar dark matter candidate but provide improved constraints on the coupling of the putative scalar field to standard matter. Our limits are complementary to previous results that were only sensitive to the fine structure constant and improve them by more than an order of magnitude when only a coupling to electromagnetism is assumed.

  12. Searching for an Oscillating Massive Scalar Field as a Dark Matter Candidate Using Atomic Hyperfine Frequency Comparisons.

    PubMed

    Hees, A; Guéna, J; Abgrall, M; Bize, S; Wolf, P

    2016-08-01

    We use 6 yrs of accurate hyperfine frequency comparison data of the dual rubidium and caesium cold atom fountain FO2 at LNE-SYRTE to search for a massive scalar dark matter candidate. Such a scalar field can induce harmonic variations of the fine structure constant, of the mass of fermions, and of the quantum chromodynamic mass scale, which will directly impact the rubidium/caesium hyperfine transition frequency ratio. We find no signal consistent with a scalar dark matter candidate but provide improved constraints on the coupling of the putative scalar field to standard matter. Our limits are complementary to previous results that were only sensitive to the fine structure constant and improve them by more than an order of magnitude when only a coupling to electromagnetism is assumed. PMID:27541455

  13. COUPLING

    DOEpatents

    Frisch, E.; Johnson, C.G.

    1962-05-15

    A detachable coupling arrangement is described which provides for varying the length of the handle of a tool used in relatively narrow channels. The arrangement consists of mating the key and keyhole formations in the cooperating handle sections. (AEC)

  14. Hyperfine structure studies of transition metals

    SciTech Connect

    Young, L.; Kurtz, C.; Hasegawa, S.

    1995-08-01

    This past year our studies of hyperfine structure (hfs) in metastable states of transition metals concentrated on the analysis of hfs in the four-valence electron system, Nb II. Earlier, we measured hfs intervals using the laser-rf double resonance and laser-induced fluorescence methods in a fast-ion beam of Nb{sup +}. The resulting experimental magnetic dipole and electric quadrupole interaction constants are compared to those calculated by a relativistic configuration interaction approach. These are the first hfs data on this refractory element. Theoretically, it is found that the most important contributions to the energy are the pair excitations, valence single excitations and core polarization from the shallow core. However, the inner core polarization is found to be crucial for hfs, albeit unimportant for energy. For the J=2 level at 12805 cm{sup -1}, 4d{sup 4} {sup 3}F. the theoretical relativistic configuration A-value is in agreement with the experimental result to an accuracy of 4%. Other calculated A-values are expected to be of the same accuracy. A paper describing these results was accepted for publication. Experimental studies of the four-valence electron system V{sup +} in the (4s+3d){sup 4} manifold are complete. The theoretical difficulties for the 3d manifold, noted earlier for the three-valence electron Ti{sup +}, as compared to the 4d manifold appear to be repeated in the case of the four-valence electron systems (Nb{sup +} and V{sup +}). Relativistic configuration interaction calculations are underway, after which a paper will be published.

  15. Nuclear Hyperfine Structure in the Donor – Acceptor Complexes (CH3)3N-BF3 and (CH)33N-B(CH3)3

    EPA Science Inventory

    The donor-acceptor complexes (CH3)3N-BF3 and (CH3)3N-B(CH3)3 have been reinvestigated at high resolution by rotational spectroscopy in a supersonic jet. Nuclear hyperfine structure resulting from both nitrogen and boron has been resolved and quadrupole coupling constants have bee...

  16. Cobalt Polyoxometalate Co4V2W18O68(10-): A Critical Investigation of Its Synthesis, Purity, and Observed (51)V Quadrupolar NMR.

    PubMed

    Folkman, Scott J; Kirner, Joel T; Finke, Richard G

    2016-06-01

    The vanadium-containing cobalt polyoxometalate (Co-POM) Co4V2W18O68(10-) (hereafter Co4V2W18) has been reported to be a stable, homogeneous water-oxidation catalyst, one with a claimed record turnover frequency that is also reportedly 200-fold faster than its phosphorus congener, Co4P2W18O68(10-). The claimed superior water-oxidation catalysis activity of the vanadium congener, Co4V2W18, rests squarely on the reported synthesis of Co4V2W18, its purity, and its stability in both the solid-state and in solution. Attempts to repeat the preparation of Co4V2W18 by either of two literature syntheses, along with the other studies reported herein, led to the discovery of multiple, convoluted problems in the prior literature of Co4V2W18. The three most serious of those problems proved to be the prior misunderstanding of the quadrupolar (herein (51)V) NMR peak widths in complexes that also contain paramagnetic metals such as Co(II), the incorrect assignment of a -506.8 ppm (51)V NMR to Co4V2W18, and then the use of that -506.8 peak to argue for the stability of Co4V2W18 in solution. The results are reported in a somewhat historical, "story" fashion en route to elucidating and fully supporting the 11 insights and take-home messages listed in the Summary and Conclusions section. PMID:27159211

  17. Computation of hyperfine energies of hydrogen, deuterium and tritium quantum dots

    NASA Astrophysics Data System (ADS)

    Çakır, Bekir; Özmen, Ayhan; Yakar, Yusuf

    2016-01-01

    The hyperfine energies and hyperfine constants of the ground and excited states of hydrogen, deuterium and tritium quantum dots(QDs) are calculated. Quantum genetic algorithm (QGA) and Hartree-Fock-Roothaan (HFR) methods are employed to calculate the unperturbed wave functions and energy eigenvalues. The results show that in the medium and strong confinement regions the hyperfine energy and hyperfine constant are strongly affected by dot radius, impurity charge, electron spin orientation, impurity spin and impurity magnetic moment. Besides, in all dot radii, the hyperfine splitting and hyperfine constant of the confined hydrogen and tritium atoms are approximately equivalent to each other and they are greater than the confined deuterium atom.

  18. Stochastic hyperfine interactions modeling library-Version 2

    NASA Astrophysics Data System (ADS)

    Zacate, Matthew O.; Evenson, William E.

    2016-02-01

    The stochastic hyperfine interactions modeling library (SHIML) provides a set of routines to assist in the development and application of stochastic models of hyperfine interactions. The library provides routines written in the C programming language that (1) read a text description of a model for fluctuating hyperfine fields, (2) set up the Blume matrix, upon which the evolution operator of the system depends, and (3) find the eigenvalues and eigenvectors of the Blume matrix so that theoretical spectra of experimental techniques that measure hyperfine interactions can be calculated. The optimized vector and matrix operations of the BLAS and LAPACK libraries are utilized. The original version of SHIML constructed and solved Blume matrices for methods that measure hyperfine interactions of nuclear probes in a single spin state. Version 2 provides additional support for methods that measure interactions on two different spin states such as Mössbauer spectroscopy and nuclear resonant scattering of synchrotron radiation. Example codes are provided to illustrate the use of SHIML to (1) generate perturbed angular correlation spectra for the special case of polycrystalline samples when anisotropy terms of higher order than A22 can be neglected and (2) generate Mössbauer spectra for polycrystalline samples for pure dipole or pure quadrupole transitions.

  19. Hyperfine magnetic fields in cobalt-based Heusler alloys

    SciTech Connect

    Yehia, M.S.

    1987-01-01

    Measurement of hyperfine interactions at Cd-111 and Sn-119 impurity nuclei in Co-based Heusler alloys Co/sub 2/YZ (Y = Mn, Ti, V, Zr and Z was Al, Ga, Ge, Si, Sn) were made within a temperature range 77 to 746 K using the time differential Perturbed Angular Correlation (TDPAC) and Mossbauer techniques. The hyperfine-field results in these alloys are discussed in terms of two models, the localized moment model and the Volume Overlap model. In the localized moment model a pre-asymptotic phase factor n = ..pi.. at distance r = a/2 was used to fit the experimental results on Co/sub 2/YZ (Y = Ti, V, Zr and Z = Al, Ga, Sn, Ge). In the Volume Overlap model the hyperfine field results in the series Co/sub 2/MnZ (Z = Ge, Si, Sn) was plotted against the lattice parameter of these alloys; a linear relationship was found, suggesting a non overlap term between the magnetic atom and the nonmagnetic impurity. A prediction of hyperfine magnetic filed less than 40 (kOe) on Sn-119 and of about -250(kOe) on Cd-111 in Co/sub 2/TiSi and Co/sub 2/TiGe is made. Temperature variation of the hyperfine magnetic field in the alloy Co/sub 2/MnSn with magnetic moments residing on two sites, has been studied. Results didn't show a dramatic deviation form the Brillouin function.

  20. Theoretical investigation of hyperfine fields in fluoromethanes and transition metal oxides

    NASA Astrophysics Data System (ADS)

    Gopalakrishnan, Gowri

    Ab-initio Hartree-Fock Cluster procedure has been used to study Nuclear Quadrupole Interaction effects in molecular solid systems and Magnetic Hyperfine properties in antiferromagnetic transition metal oxides. Using the molecular orbital wave functions obtained from the Hartree-Fock calculations, the nuclear quadrupole interaction parameters, namely, the asymmetry parameter and quadrupole coupling constants are calculated at the fluorine site in CHsb{4-n}Fsb{n} (n = 1,2,3) and CHClFsb2 molecules. In addition to these molecules, the possibility of complexing of HF* molecule to these host molecules is also investigated. This complex formation is found to give rise to a second frequency at the fluorine site arising from the fluorine atom of the HF* hydrogen bonded to the host molecule. All of these results agree well with those from Time Dependent Perturbed Angular Distribution measurements of quadrupole interactions at the fluorine site in these systems. Theoretical investigations have also been carried out for the transition metal oxides NiO and MnO in antiferromagnetic state. The location of the muon in the two oxides and the associated electronic structure and muon hyperfine properties have been investigated. Eight equilibrium positions for the muon are found around each oxygen ion in the crystal, of which two are found to have substantially stronger stability than the other six. Direct and exchange contributions to the contact and dipolar hyperfine fields from within the cluster and dipolar fields from outside, are evaluated for each of the equilibrium locations of the muon and are shown to lead to three sets of hyperfine fields. The nature of the potential experienced by the muon as it travels between the equilibrium sites is studied to understand its dynamics inside the solid. The rates of hopping between each of the two equivalent most stable sites, where the muon most strongly trapped, and the other six sites are studied. In each case, the combination of

  1. Hyperfine-mediated static polarizabilities of monovalent atoms and ions

    SciTech Connect

    Dzuba, V. A.; Flambaum, V. V.; Beloy, K.; Derevianko, A.

    2010-12-15

    We apply relativistic many-body methods to compute static differential polarizabilities for transitions inside the ground-state hyperfine manifolds of monovalent atoms and ions. Knowledge of this transition polarizability is required in a number of high-precision experiments, such as microwave atomic clocks and searches for CP-violating permanent electric dipole moments. While the traditional polarizability arises in the second order of interaction with the externally applied electric field, the differential polarizability involves an additional contribution from the hyperfine interaction of atomic electrons with nuclear moments. We derive formulas for the scalar and tensor polarizabilities including contributions from magnetic dipole and electric quadrupole hyperfine interactions. Numerical results are presented for Al, Rb, Cs, Yb{sup +}, Hg{sup +}, and Fr.

  2. First observation of muonic hyperfine effects in pure deuterium

    SciTech Connect

    Kammel, P.; Breunlich, W.H.; Cargnelli, M.; Mahler, H.G.; Zmeskal, J.; Bertl, W.H.; Petitjean, C.

    1983-11-01

    We discovered a strong hyperfine dependence of the resonant formation process of d..mu..d mesomolecules, while detecting neutrons from muon-catalyzed fusion in pure deuterium gas at 34 K. This new effect enabled us to observe directly transitions between hyperfine states of the ..mu..d atom for the first time and to determine an accurate experimental value for this transition rate. Our analysis demonstrates the importance of hyperfine effects for the quantitative understanding of the mechanism of resonant d..mu..d formation. Moreover, this experiment indicates that the resonant formation process is a powerful tool for a refined spectroscopy of d..mu..d bound states. Finally, the detailed knowledge about mesoatomic and mesomolecular processes obtained in this work provides valuable information for the analysis of experiments on the elementary muon-capture process in deuterium.

  3. A measurement of the hyperfine structure of CO-17

    NASA Technical Reports Server (NTRS)

    Frerking, M. A.; Langer, W. D.

    1981-01-01

    It is pointed out that the isotope of carbon monoxide, CO-17, has appreciable hyperfine structure caused by the electric quadrupole and the magnetic dipole interactions of the O-17 nucleus which has a spin of 5/3. During a radioastronomical study of the structure and dynamics of cold interstellar clouds, it was found that the Bok globule B335 had an extremely small velocity dispersion such that the hyperfine components are clearly resolved. A graph is provided which shows the antenna temperature (a measure of intensity) of the CO-17 emission as a function of frequency. The hyperfine constants and line frequencies were redetermined for the CO-17 J=1 yields 0 rational transition. The observation of CO-17 was carried out with a 7 meter Cassegrain antenna during 1979 and 1980. The CO-17 molecular line parameters are listed in a table.

  4. A multireference configuration interaction study of the hyperfine structure of the molecules CCO, CNN, and NCN in their triplet ground states

    NASA Astrophysics Data System (ADS)

    Suter, H. U.; Huang, M.-B.; Engels, B.

    1994-11-01

    The hyperfine structures of the isoelectronic molecules CCO, CNN, and NCN in their triplet ground states (X 3Σ-) are investigated by means of ab initio methods. The infrared frequencies and geometries are determined and compared with experiment. Configuration selected multireference configuration interaction calculations in combination with perturbation theory to correct the wave function (MRD-CI/BK) employing extended atomic orbital (AO) basis sets yielded very accurate hyperfine properties. The theoretical values for CCO are in excellent agreement with the experimental values determined by Smith and Weltner [J. Chem. Phys. 62, 4592 (1975)]. For CNN, the first assignment of Smith and Weltner for the two nitrogen atoms has to be changed. A qualitative discussion of the electronic structure discloses no simple relation between the structure of the singly occupied orbitals and the measured hyperfine coupling constants. Vibrational effects were found to be of little importance.

  5. Magnetic blackbody shift of hyperfine transitions for atomic clocks

    SciTech Connect

    Berengut, J. C.; Flambaum, V. V.; King-Lacroix, J.

    2009-12-15

    We derive an expression for the magnetic blackbody shift of hyperfine transitions such as the cesium primary reference transition which defines the second. The shift is found to be a complicated function of temperature, and has a T{sup 2} dependence only in the high-temperature limit. We also calculate the shift of ground-state p{sub 1/2} hyperfine transitions which have been proposed as new atomic clock transitions. In this case interaction with the p{sub 3/2} fine-structure multiplet may be the dominant effect.

  6. A computer program for analyzing unresolved Mossbauer hyperfine spectra

    NASA Technical Reports Server (NTRS)

    Schiess, J. R.; Singh, J. J.

    1978-01-01

    The program for analyzing unresolved Mossbauer hyperfine spectra was written in FORTRAN 4 language for the Control Data CYBER 170 series digital computer system with network operating system 1.1. With the present dimensions, the program requires approximately 36,000 octal locations of core storage. A typical case involving two innermost coordination shells in which the amplitudes and the peak positions of all three components were estimated in 25 iterations requires 30 seconds on CYBER 173. The program was applied to determine the effects of various near neighbor impurity shells on hyperfine fields in dilute FeAl alloys.

  7. Measurement of Muonium Hyperfine Splitting at J-PARC

    NASA Astrophysics Data System (ADS)

    Tanaka, K. S.; Aoki, M.; Iinuma, H.; Ikedo, Y.; Ishida, K.; Iwasaki, M.; Ueno, Y.; Ohkubo, R.; Ogitsu, T.; Kadono, R.; Kamigaito, O.; Kawamura, N.; Kawall, D.; Kanda, S.; Kubo, K.; Kume, T.; Koda, A.; Kojima, K.; Saito, N.; Sakamoto, N.; Sasaki, K.; Shimomura, K.; Sugano, M.; Tomono, D.; Toyoda, A.; Torii, H. A.; Torikai, E.; Nagamine, K.; Nishiyama, K.; Strasser, P.; Fukao, Y.; Fujiwara, Y.; Matsuda, Y.; Mibe, T.; Miyake, Y.; Yoshida, M.

    We are planning a measurement of the ground state hyperfine structure of muonium at J-PARC/MLF. Muonium is a hydrogen-like bound state of leptons, and its is a good probe for testing QED theory. The muon mass and magnetic moment which are fundamental constants of muon have been so far determined by the ground state hyperfine structure of muonium (muonium HFS) experiment at LAMPF [1]. To estimte the systematic uncertainties in our experiment, we developed a simulation tool to estimate the systematic uncertainties from several sources in our experiment. The progress of estimation of uncertainties by this tool, development of detectors, and NMR probes are presented.

  8. The Relativistic Study of Hyperfine Interactions in Ionic Systems.

    NASA Astrophysics Data System (ADS)

    Panigrahy, Surya Narayan

    1991-02-01

    The Brueckner-Goldstone perturbation theory as formulated relativistically has been applied to the study of hyperfine interactions in the lithium-like ions Li ^0, Be^{+1}, B^{+2}, C^ {+3}, N^{+4} , O^{+5}, F ^{+6}, Ne^{+7 } and Bi^{+80}; in the alkaline earth ions Ra^+ and Sr^+; and in the Group 12 ions Zn^+, Cd^+, and Hg^+, isoelectronic with the Group II atoms Cu, Ag, and Au. We have employed the graphical representation of the theory, where Feynman diagrams are associated with physical effects such as the valence, exchange core polarization, the consistency, and correlation. Contributions from radiative effects are estimated for these systems using a hydrogenic model. The contributions of both exchange core polarization and correlation as ratios of the valence contribution decrease as the degree of ionization and nuclear charge increase; the decrease in much more rapid for the correlation effect. Radiative effects, on the other hand, increase very rapidly with increasing charge, becoming of the same order of magnitude as correlation effects in O^{+5}. For Bi ^{+80} the radiative effect is 0.3% of the valence electron's contribution to the hyperfine field and is larger than the correlation. Our purpose in calculating the hyperfine field for the ^ {213}Ra^+ ion is to evaluate magnetic moments of other Ra isotopes from experimentally determined ratios of magnetic moments. The total hyperfine field obtained for ^{213 }Ra^+ is 1232 tesla (T); when combined with the experimental hyperfine constant from Zeeman measurements, this yields a nuclear magnetic moment of 0.610 +/- 0.006 mu_{rm N}, where mu_{rm N} is the nuclear magneton. Calculations for Zn^+, Cd^+, and Hg^+ have been performed in order to compare the trends of various contributions to the hyperfine fields for these systems from different mechanisms with those of alkali atoms and alkaline-earth ions. Our calculated hyperfine fields of Zn^+, Cd^+, and Hg^+ are 451 +/- 9 T, 795 +/- 15 T, and 2642 +/- 63 T

  9. Hyperfine Coherence in the Presence of Spontaneous Photon Scattering

    SciTech Connect

    Ozeri, R.; Langer, C.; Jost, J.D.; Marco, B. de; Ben-Kish, A.; Blakestad, B.R.; Britton, J.; Chiaverini, J.; Itano, W.M.; Hume, D.B.; Leibfried, D.; Rosenband, T.; Schmidt, P.O.; Wineland, D.J.

    2005-07-15

    The coherence of a hyperfine-state superposition of a trapped {sup 9}Be{sup +} ion in the presence of off-resonant light is studied experimentally. It is shown that Rayleigh elastic scattering of photons that does not change state populations also does not affect coherence. We observe coherence times that exceed the average scattering time of 19 photons which is determined from measured Stark shifts. This result implies that, with sufficient control over its parameters, laser light can be used to manipulate hyperfine-state superpositions with very little decoherence.

  10. Hyperfine Structure Constant of the Neutron Halo Nucleus Be+11

    NASA Astrophysics Data System (ADS)

    Takamine, A.; Wada, M.; Okada, K.; Sonoda, T.; Schury, P.; Nakamura, T.; Kanai, Y.; Kubo, T.; Katayama, I.; Ohtani, S.; Wollnik, H.; Schuessler, H. A.

    2014-04-01

    The hyperfine splittings of ground state Be+11 have been measured precisely by laser-microwave double resonance spectroscopy for trapped and laser cooled beryllium ions. The ions were produced at relativistic energies and subsequently slowed down and trapped at mK temperatures. The magnetic hyperfine structure constant of Be+11 was determined to be A11=-2677.302 988(72) MHz from the measurements of the mF-mF'=0-0 field independent transition. This measurement provides essential data for the study of the distribution of the halo neutron in the single neutron halo nucleus Be11 through the Bohr-Weisskopf effect.

  11. 7P1/2 hyperfine splitting in 206 , 207 , 209 , 213Fr and the hyperfine anomaly

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Orozco, L. A.; Collister, R.; Gwinner, G.; Tandecki, M.; Behr, J. A.; Pearson, M. R.; Gomez, E.; Aubin, S.

    2013-05-01

    We perform precision measurements on francium, the heaviest alkali with no stable isotopes, at the recently commissioned Francium Trapping Facility at TRIUMF. A combination of RF and optical spectroscopy allows better than 10 ppm (statistical) measurements of the 7P1 / 2 state hyperfine splitting for the isotopes 206 , 207 , 209 , 213Fr, in preparation for weak interaction studies. Together with previous measurements of the ground state hyperfine structure, it is possible to extract the hyperfine anomaly. This is a correction to the point interaction of the nuclear magnetic moment and the electron wavefunction, known as the Bohr Weisskopf effect. Our measurements extend previous measurements to the neutron closed shell isotope (213) as well as further in the neutron deficient isotopes (206, 207). Work supported by NSERC and NRC from Canada, NSF and DOE from USA, CONYACT from Mexico.

  12. Spectrally resolved hyperfine interactions between polaron and nuclear spins in organic light emitting diodes: Magneto-electroluminescence studies

    NASA Astrophysics Data System (ADS)

    Crooker, S. A.; Liu, F.; Kelley, M. R.; Martinez, N. J. D.; Nie, W.; Mohite, A.; Nayyar, I. H.; Tretiak, S.; Smith, D. L.; Ruden, P. P.

    2014-10-01

    We use spectrally resolved magneto-electroluminescence (EL) measurements to study the energy dependence of hyperfine interactions between polaron and nuclear spins in organic light-emitting diodes. Using layered devices that generate bright exciplex emission, we show that the increase in EL emission intensity I due to small applied magnetic fields of order 100 mT is markedly larger at the high-energy blue end of the EL spectrum (ΔI/I ˜ 11%) than at the low-energy red end (˜4%). Concurrently, the widths of the magneto-EL curves increase monotonically from blue to red, revealing an increasing hyperfine coupling between polarons and nuclei and directly providing insight into the energy-dependent spatial extent and localization of polarons.

  13. Spectrally resolved hyperfine interactions between polaron and nuclear spins in organic light emitting diodes: Magneto-electroluminescence studies

    SciTech Connect

    Crooker, S. A.; Kelley, M. R.; Martinez, N. J. D.; Nie, W.; Mohite, A.; Nayyar, I. H.; Tretiak, S.; Smith, D. L.; Liu, F.; Ruden, P. P.

    2014-10-13

    We use spectrally resolved magneto-electroluminescence (EL) measurements to study the energy dependence of hyperfine interactions between polaron and nuclear spins in organic light-emitting diodes. Using layered devices that generate bright exciplex emission, we show that the increase in EL emission intensity I due to small applied magnetic fields of order 100 mT is markedly larger at the high-energy blue end of the EL spectrum (ΔI/I ∼ 11%) than at the low-energy red end (∼4%). Concurrently, the widths of the magneto-EL curves increase monotonically from blue to red, revealing an increasing hyperfine coupling between polarons and nuclei and directly providing insight into the energy-dependent spatial extent and localization of polarons.

  14. Hyperfine Parameters for Aluminum Hydride: An ab Initio Molecular Orbital Study

    NASA Astrophysics Data System (ADS)

    Gee, Myrlene; Wasylishen, Roderick E.

    2001-06-01

    An extensive ab initio molecular orbital study of the 27Al nuclear spin-rotation and nuclear quadrupolar coupling constants in aluminum hydride, AlH, has been performed. The 27Al nuclear spin-rotation constant (C⊥), calculated to be approximately 300 kHz, was neglected in a previous analysis of the hyperfine structure in the microwave spectrum (M. Goto and S. Saito, Astrophys. J.452, L147-148 (1995)). Unfortunately, the ab initio calculations do not provide a definitive value for the aluminum nuclear quadrupolar coupling constant, but suggest a value of -49±4 MHz. It is apparent that the microwave study of AlH should be repeated.

  15. Nonlinear Pressure Shifts of ^133Cs Hyperfine Frequencies

    NASA Astrophysics Data System (ADS)

    Gong, Fei; Jau, Yuan-Yu; Happer, William

    2008-05-01

    The hyperfine (microwave) magnetic-resonance frequencies of optically pumped alkali-metal atoms in buffer-gas have long been used in compact, portable frequency standards. Van der Waals molecules, consisting of an alkali-metal atom loosely bound to a buffer gas atom, can form in such vapor cells. The molecules strongly affect the spin relaxation of alkali metal atoms in Ar, Kr and Xe gases at pressures of a few Torr, where the collisionally limited lifetime of the molecules is comparable to the characteristic period of the spin-rotation interaction between the rotational angular momentum N of the molecule and the electron spin S of the alkali-metal atom. The hyperfine-shift interaction, the modification a nearby buffer-gas atom makes to the Fermi contact interaction between S and the nuclear spin I of the alkali atom, can contribute to the width of the microwave resonance line, and it is responsible for the pressure shifts of the hyperfine resonance frequencies that are so important for clocks. Major improvements have been done to the apparatus and the process of data taking since last time. The experimental results show that Van der Waals molecules also modify the effects of the hyperfine-shift interaction. For Ar or Kr pressures of a few tens of Torr or less, the shift of the microwave resonance frequency of Cs is not linear in the buffer gas pressure.

  16. Nonlinear Pressure Shifts of ^133Cs Hyperfine Frequencies

    NASA Astrophysics Data System (ADS)

    Gong, Fei; Jau, Yuan-Yu; Happer, William

    2007-06-01

    The hyperfine (microwave) magnetic-resonance frequencies of optically pumped alkali-metal atoms in buffer-gas have long been used in compact, portable frequency standards. The buffer gas is needed to slow down the diffusion of optically pumped atoms to the cell walls, and to eliminate Doppler broadening of the microwave resonances. Van der Waals molecules, consisting of an alkali-metal atom loosely bound to a buffer gas atom, can form in such vapor cells. The molecules strongly affect the spin relaxation of alkali metal atoms in Ar, Kr and Xe gases at pressures of a few Torr. The hyperfine-shift interaction, δAI.S, the modification a nearby buffer-gas atom makes to the Fermi contact interaction between S and the nuclear spin I of the alkali atom, can contribute to the width of the microwave resonance line, and it is responsible for the pressure shifts of the hyperfine resonance frequencies that are so important for clocks. Our experiments show that Van der Waals molecules also modify the effects of the hyperfine-shift interaction δAI.S. For Ar pressures of a few tens of Torr or less, the shift of the microwave resonance frequency of ^133Cs in Ar buffer gas is not linear in the buffer gas pressure. This occurs because the contribution to the pressure shift from molecules is suppressed when τδA I > h.

  17. On the observability of optically thin coronal hyperfine structure lines

    SciTech Connect

    Chatzikos, M.; Ferland, G. J.; Williams, R. J. R.; Fabian, A. C.

    2014-06-01

    We present CLOUDY calculations for the intensity of coronal hyperfine lines in various environments. We model indirect collisional and radiative transitions, and quantify the collisionally excited line emissivity in the density-temperature phase space. As an observational aid, we also express the emissivity in units of that in the 0.4-0.7 keV band. For most hyperfine lines, knowledge of the X-ray surface brightness and the plasma temperature is sufficient for rough estimates. We find that the radiation fields of both Perseus A and Virgo A can enhance the populations of highly ionized species within 1 kpc. They can also enhance line emissivity within the cluster core. This could have implications for the interpretation of spectra around bright active galactic nuclei. We find the intensity of the {sup 57}Fe XXIV λ3.068 mm line to be about two orders of magnitude fainter than previously thought, at ∼20 μK. Comparably bright lines may be found in the infrared. Finally, we find the intensity of hyperfine lines in the Extended Orion Nebula to be low, due to the shallow sightline. Observations of coronal hyperfine lines will likely be feasible with the next generation of radio and submillimeter telescopes.

  18. Isotope shifts and hyperfine structure of the laser-cooling Fe I 358-nm line

    NASA Astrophysics Data System (ADS)

    Huet, N.; Pettens, M.; Bastin, T.

    2015-11-01

    We report on the measurement of the isotope shifts of the 3 d74 s a 5F5-3 d74 p z 5G6o Fe i line at 358 nm between all four stable isotopes ,Fe56Fe54,Fe57 , and Fe58 , as well as the hyperfine structure of that line for Fe57 , the only stable isotope having a nonzero nuclear spin. This line is of primary importance for laser-cooling applications. In addition, an experimental value of the field and specific mass shift coefficients of the transition is reported as well as the hyperfine structure magnetic dipole coupling constant A of the transition excited state in Fe57 , namely A (3 d74 p z 5G6o) =31.241 (48 ) MHz. The measurements were carried out by means of laser-induced fluorescence spectroscopy performed on an isotope-enriched iron atomic beam. All measured frequency shifts are reported with relative uncertainties below one third percent.

  19. Electronic Structure and the Magnetic Hyperfine Interactions in Heme Unit of Metmyoglobin

    NASA Astrophysics Data System (ADS)

    Maharjan, N. B.; Badu, S. R.; Dubey, Archana; Scheicher, R. H.; Pink, R. H.; Chow, Lee; Schulte, A.; Saha, H. P.; Das, T. P.

    2008-03-01

    The ^14N and ^57mFe hyperfine interactions in the heme unit of metmyoglobin are available experimentally by electron-nuclear double resonance (ENDOR) and Mossbauer spectroscopic techniques. We have carried out electronic structure investigations on the heme system including the H2O and proximal imidazole ligands by the first-principles Hartree-Fock procedure and studied the magnetic hyperfine and nuclear quadrupole coupling constants for the ^57mFe nucleus and all the six ^14N nuclei on the four pyrrole and imidazole ligands as well as the ^17O nucleus on the H2O ligand. Comparison will be made with available experimental data [1, 2] and earlier theoretical investigations [3] by the approximate self-consistent charge Extended Huckel procedure. Results will also be presented for the optical frequencies and intensities from transitions between ligand-like and iron d-like states and the Fe-Nɛ vibrational frequency [1] G. Lang, Q. Rev. Biophys. 3, 1 (1970) [2] C.P. Scholes, R.A. Isaacson and G Feher, Biochim. Biophys. Acta 263,448(1972) [3] S.K. Mun, Jane C. Chang and T.P. Das J. Am. Chem. Soc. 101, 5562(1979)

  20. Comparison of reactions for the production of 258,257Db: 208Pb(51V,xn) and 209Bi(50Ti,xn)

    SciTech Connect

    Gates, Jacklyn M.; Nelson, Sarah L.; Gregorich, Kenneth E.; Dragojevic, Irena; Dullmann, Christoph E.; Ellison, Paul A.; Folden III, Charles M.; Garcia, Mitch A.; Stavsetra, Liv; Sudowe, Ralf; Hoffman, Darleane C.; Nitsche, Heino

    2008-09-29

    Excitation functions for the 1n and 2n exit channels of the 208Pb(51V,xn)259-xDb reaction were measured. A maximum cross section of the 1n exit channel of 2070+1100/-760 pb was measured at an excitation energy of 16.0 +- 1.8 MeV. For the 2n exit channel, a maximum cross section of 1660+450/-370 pb was measured at 22.0 +- 1.8 MeV excitation energy. The 1n excitation function for the 209Bi(50Ti,n)258Db reaction was remeasured, resulting in a cross section of 5480+1750/-1370 pb at an excitation energy of 16.0 +- 1.6 MeV, in agreement with previous values [F. P. Hebberger, et al., Eur. Phys. J. A 12, 57 (2001)]. Differences in cross section maxima are discussed in terms of the fusion probability below the barrier.

  1. Studies of vanadium-phosphorus-oxygen selective oxidation catalysts by sup 31 P and sup 51 V NMR spin-echo and volume susceptibility measurements

    SciTech Connect

    Li, Juan.

    1991-10-01

    The purpose of this work is to characterize the vanadium-phosphorous oxide (V-P-O) catalysts for the selective oxidation of n-butane and 1-butene to maleic anhydride. The utility of solid state nuclear magnetic resonance as an analytical tool in this investigation lies in its sensitivity to the electronic environment surrounding the phosphorous and vanadium nuclei, and proximity of paramagnetic species. Spin-echo mapping NMR of {sup 31}p and {sup 51}v and volume magnetic susceptibility measurements were used as local microscopic probes of the presence of V{sup 5+}, V{sup 4+}, V{sup 3+} species in the model compounds: {beta}-VOPO{sub 4}, {beta}-VOPO{sub 4} treated with n-butane/1-butene, (VO){sub 2}P{sub 2}O{sub 7} treated with n-butane/1-butene; and industrial catalysts with P/V (phosphorus to vanadium) ratio of 0.9, 1.0 and 1.1, before and after treatment with n-butane and 1-butene. The NMR spectra provide a picture of how the oxidation states of vanadium are distributed in these catalysts. 73 refs., 32 figs., 8 tabs.

  2. The (biological) speciation of vanadate(V) as revealed by (51)V NMR: A tribute on Lage Pettersson and his work.

    PubMed

    Rehder, Dieter

    2015-06-01

    Four decades of research carried out by Lage Pettersson, his group and his coworkers are reviewed, research that has been directed predominantly towards the speciation of vanadate and systems containing, along with vanadate and co-reactants such as phosphate and peroxide, biologically relevant organics. In particular, those organics have been addressed that either are (potential) ligands for vanadate-derived coordination compounds generated at physiological conditions and/or function as constituents in medicinally interesting oxidovanadium compounds. Examples for molecules introduced in the context of the physiological vanadate-ligand interaction include the dipeptides Pro-Ala, Ala-Gly, Ala-His and Ala-Ser, the serum constituents lactate and citrate, and the nucleobases adenosine and uridine. The speciation in the vanadate-picolinate and vanadate-maltol systems is geared towards insulin-enhancing vanadium drugs. The speciation as a function of pH, ionic strength and the concentration of vanadate and the ligand(s) is based on potentiometric and (51)V NMR investigations, a methodical combination that allows reliable access to composition, formation constants and, to some extent, also structural details for the manifold of species present in aqueous media at physiological pH and beyond. The time frame 1971 to 2014 is reviewed, emphasizing the interval 1985 to 2006, and thus focusing on biologically interesting vanadium systems. Figurative representations from the original literature have been included. PMID:25592749

  3. Combined effect of coherent Z exchange and the hyperfine interaction in the atomic parity-nonconserving interaction

    SciTech Connect

    Johnson, W.R.; Safronova, M.S.; Safronova, U.I.

    2003-06-01

    The nuclear spin-dependent parity-nonconserving (PNC) interaction arising from a combination of the hyperfine interaction and the coherent, spin-independent, PNC interaction from Z exchange is evaluated using many-body perturbation theory. For the 6s{sub 1/2}-7s{sub 1/2} transition in {sup 133}Cs, we obtain a result that is about 40% smaller than that found previously by Bouchiat and Piketty [Phys. Lett. B 269, 195 (1991)]. Applying this result to {sup 133}Cs leads to an increase in the experimental value of nuclear anapole moment and exacerbates differences between constraints on PNC meson coupling constants obtained from the Cs anapole moment and those obtained from other nuclear parity violating experiments. Nuclear spin-dependent PNC dipole matrix elements, including contributions from the combined weak-hyperfine interaction, are also given for the 7s{sub 1/2}-8s{sub 1/2} transition in {sup 211}Fr and for transitions between ground-state hyperfine levels in K, Rb, Cs, Ba{sup +}, Au, Tl, Fr, and Ra{sup +}.

  4. First principles density functional calculation of magnetic moment and hyperfine fields of dilute transition metal impurities in Gd host

    NASA Astrophysics Data System (ADS)

    Mohanta, S. K.; Mishra, S. N.; Srivastava, S. K.

    2014-04-01

    We present first principles calculations of electronic structure and magnetic properties of dilute transition metal (3d, 4d and 5d) impurities in a Gd host. The calculations have been performed within the density functional theory using the full potential linearized augmented plane wave technique and the GGA+U method. The spin and orbital contributions to the magnetic moment and the hyperfine fields have been computed. We find large magnetic moments for 3d (Ti-Co), 4d (Nb-Ru) and 5d (Ta-Os) impurities with magnitudes significantly different from the values estimated from earlier mean field calculation [J. Magn. Magn. Mater. 320 (2008) e446-e449]. The exchange interaction between the impurity and host Gd moments is found to be positive for early 3d elements (Sc-V) while in all other cases an anti-ferromagnetic coupling is observed. The trends for the magnetic moment and hyperfine field of d-impurities in Gd show qualitative difference with respect to their behavior in Fe, Co and Ni. The calculated total hyperfine field, in most cases, shows excellent agreement with the experimental results. A detailed analysis of the Fermi contact hyperfine field has been made, revealing striking differences for impurities having less or more than half filled d-shell. The impurity induced perturbations in host moments and the change in the global magnetization of the unit cell have also been computed. The variation within each of the d-series is found to correlate with the d-d hybridization strength between the impurity and host atoms.

  5. Hyperfine spectroscopic study of Laves phase HfFe 2

    NASA Astrophysics Data System (ADS)

    Belošević-Čavor, J.; Novaković, N.; Cekić, B.; Ivanović, N.; Manasijević, M.

    2004-05-01

    Hyperfine fields in HfFe 2 were measured at 181Ta probe using the time-differential perturbed angular correlation method (TDPAC) in the temperature range 78-1200 K. Analysis of the spectra revealed two interactions with hyperfine fields of 13.82(7) T and 8.0(2) T, at 293 K. First is ascribed to the interaction at the 8a position in the cubic C15 structure. The second can be assigned to a minor amount of hexagonal C14 phase, or to an irregular position of the probe in the C15 lattice. Results of calculations using LAPW-WIEN97 are in a good agreement with experiment.

  6. Hyperfine structure constant of the neutron halo nucleus (11)Be(+).

    PubMed

    Takamine, A; Wada, M; Okada, K; Sonoda, T; Schury, P; Nakamura, T; Kanai, Y; Kubo, T; Katayama, I; Ohtani, S; Wollnik, H; Schuessler, H A

    2014-04-25

    The hyperfine splittings of ground state Be+11 have been measured precisely by laser-microwave double resonance spectroscopy for trapped and laser cooled beryllium ions. The ions were produced at relativistic energies and subsequently slowed down and trapped at mK temperatures. The magnetic hyperfine structure constant of Be+11 was determined to be A11=-2677.302 988(72)  MHz from the measurements of the mF-mF'=0-0 field independent transition. This measurement provides essential data for the study of the distribution of the halo neutron in the single neutron halo nucleus Be11 through the Bohr-Weisskopf effect. PMID:24815642

  7. Chiral Extrapolation of Lattice Data for Heavy Meson Hyperfine Splittings

    SciTech Connect

    X.-H. Guo; P.C. Tandy; A.W. Thomas

    2006-03-01

    We investigate the chiral extrapolation of the lattice data for the light-heavy meson hyperfine splittings D*-D and B*-B to the physical region for the light quark mass. The chiral loop corrections providing non-analytic behavior in m{sub {pi}} are consistent with chiral perturbation theory for heavy mesons. Since chiral loop corrections tend to decrease the already too low splittings obtained from linear extrapolation, we investigate two models to guide the form of the analytic background behavior: the constituent quark potential model, and the covariant model of QCD based on the ladder-rainbow truncation of the Dyson-Schwinger equations. The extrapolated hyperfine splittings remain clearly below the experimental values even allowing for the model dependence in the description of the analytic background.

  8. Enhanced hyperfine-induced spin dephasing in a magnetic field gradient

    NASA Astrophysics Data System (ADS)

    Beaudoin, Felix; Coish, William A.

    2013-03-01

    Magnetic field gradients are important for single-site addressability and electric-dipole spin resonance of electrons in quantum dots or in donor impurities. We show that these advantages are offset by a potential reduction in coherence time. Although the magnetic field appears uniform to the electron, it provides a non-uniform field for the nuclear-spin bath. This leads to a finite bath correlation time, preventing the full recovery of electron-spin coherence. We apply our model to single electron spins in quantum dots and single donor impurities, singlet-triplet spin qubits, and consider both free-induction decay and spin-echo. This mechanism can dominate over known dephasing sources due to nuclear dipole-dipole interactions and hyperfine flip-flops. This result is especially important for systems requiring large magnetic field gradients, including spin qubits coupled to superconducting stripline resonators. We acknowledge FRQNT, INTRIQ, NSERC and CIFAR for funding.

  9. Revised energy levels and hyperfine structure constants of Ta II

    NASA Astrophysics Data System (ADS)

    Windholz, Laurentius; Arcimowicz, Bronislaw; Uddin, Zaheer

    2016-06-01

    Using a wave number calibrated Fourier transform spectrum, we determined the energy levels of the first ion of tantalum with high accuracy. To get the correct center of gravity wave numbers of the observed spectral lines, the knowledge of the hyperfine constants of the involved levels was necessary. From the observed values we deduced the energy levels in a global fit. A comparison between our results and all available literature values is presented.

  10. Hyperfine transition in light muonic atoms of odd Z

    NASA Astrophysics Data System (ADS)

    Stocki, T. J.; Measday, D. F.; Gete, E.; Saliba, M. A.; Lange, J.; Gorringe, T. P.

    2001-10-01

    The hyperfine (hf) transition rates for muonic atoms have been remeasured for select light nuclei, using neutron detectors to evaluate the time dependence of muon capture. For 19F Λh=5.6(2) μs-1 for the hf transition rate, a value that is considerably more accurate than previous measurements. Results are also reported for Na, Al, P, Cl, and K.

  11. First Optical Hyperfine Structure Measurement in an Atomic Anion

    SciTech Connect

    Fischer, A.; Canali, C.; Warring, U.; Kellerbauer, A.; Fritzsche, S.

    2010-02-19

    We have investigated the hyperfine structure of the transition between the 5d{sup 7}6s{sup 2} {sup 4}F{sub 9/2}{sup e} ground state and the 5d{sup 6}6s{sup 2}6p {sup 6}D{sub J}{sup o} excited state in the negative osmium ion by high-resolution collinear laser spectroscopy. This transition is unique because it is the only known electric-dipole transition in atomic anions and might be amenable to laser cooling. From the observed hyperfine structure in {sup 187}Os{sup -} and {sup 189}Os{sup -} the yet unknown total angular momentum of the bound excited state was found to be J=9/2. The hyperfine structure constants of the {sup 4}F{sub 9/2}{sup e} ground state and the {sup 6}D{sub 9/2}{sup o} excited state were determined experimentally and compared to multiconfiguration Dirac-Fock calculations. Using the knowledge of the ground and excited state angular momenta, the full energy level diagram of {sup 192}Os{sup -} in an external magnetic field was calculated, revealing possible laser cooling transitions.

  12. Mapping the magnetic hyperfine field in GdCo5

    NASA Astrophysics Data System (ADS)

    Krylov, V. I.; Bosch-Santos, B.; Cabrera-Pasca, G. A.; Delyagin, N. N.; Carbonari, A. W.

    2016-05-01

    The magnetic hyperfine field (Bhf) in ferrimagnetic GdCo5 compound has been investigated as a function of temperature by Mössbauer effect (ME) spectroscopy and perturbed angular correlation (PAC) spectroscopy using 119Sn and 111Cd probe nuclei, respectively. Results show that the non-magnetic probe atoms 119Sn and 111Cd substitute all three non-equivalent positions in GdCo5: Gd, CoI, and CoII. For 119Sn and 111Cd probes at Gd sites, the saturation magnetic hyperfine fields are very different with values of Bhf1 = 57.0(1) T and Bhf1= 20.7(1) T, respectively. For 119Sn and 111Cd atoms localized at CoI and CoII sites the magnetic hyperfine fields are practically identical and, in saturation, reach the values of Bhf2 = 11.6(1) T and Bhf2 = 11.1(2) T, and Bhf3 = 14.8(1) T and Bhf3 = 14.4(2) T, respectively.

  13. First observation of two hyperfine transitions in antiprotonic 3He

    PubMed Central

    Friedreich, S.; Barna, D.; Caspers, F.; Dax, A.; Hayano, R.S.; Hori, M.; Horváth, D.; Juhász, B.; Kobayashi, T.; Massiczek, O.; Sótér, A.; Todoroki, K.; Widmann, E.; Zmeskal, J.

    2011-01-01

    We report on the first experimental results for microwave spectroscopy of the hyperfine structure of p¯3He+. Due to the helium nuclear spin, p¯3He+ has a more complex hyperfine structure than p¯4He+, which has already been studied before. Thus a comparison between theoretical calculations and the experimental results will provide a more stringent test of the three-body quantum electrodynamics (QED) theory. Two out of four super-super-hyperfine (SSHF) transition lines of the (n,L)=(36,34) state were observed. The measured frequencies of the individual transitions are 11.12559(14) GHz and 11.15839(18) GHz, less than 1 MHz higher than the current theoretical values, but still within their estimated errors. Although the experimental uncertainty for the difference of these frequencies is still very large as compared to that of theory, its measured value agrees with theoretical calculations. This difference is crucial to be determined because it is proportional to the magnetic moment of the antiproton. PMID:21822351

  14. First-principles investigation of electronic structure and hyperfine properties of heme and nitrosyl-hemoglobin systems

    NASA Astrophysics Data System (ADS)

    Pujari, Minakhi

    This thesis is devoted to study of electronic structures and associated hyperfine properties of molecular systems. The main emphasis of our work is on the electronic structure and hyperfine properties of nitrosyl-hemoglobin and the sensitiveness of the structure to external conditions as this compound is closely related to deoxy-hemoglobin, the most important enzyme of the human body. The other two systems of compounds, sixth group hexafluorides and five-liganded halogen-heme compounds have been studied to test the accuracy of the Hartree-Fock procedure employed in explaining the properties of systems related in different degrees to nitrosyl-hemoglobin. In the hexafluoride systems, the theoretical values obtained in our work for the Nuclear Quadrupole Coupling Constant (NQCC) of 19F*, explain the experimental trend of continuous decrease from lightest to the heaviest systems. This is in keeping with the empirical Townes and Dailey relation and the expected increase in ionicity in going to the heavier systems. In bromo-hemin and iodo-hemin, the magnetic hyperfine properties of 57Fe, 14N, 13C, protons and halogen nuclei were studied. The associated charge and unpaired spin population obtained using their calculated electronic structures indicated more localized charge and spin distribution than were found by the semi-empirical method of Self-Consistent Charge Extended Hückel Procedure. Our results for the hyperfine constants showed satisfactory agreement with available experimental data. The contact and dipolar contribution to the hyperfine constant and their breakdown into direct and exchange polarization contributions were analyzed. The isomer shift at the 57Fe nucleus for both the systems, bromo-hemin and iodo-hemin were also studied and the observed trend was in agreement with that for other related compounds. The studies of the sixth group hexafluorides, and bromo- hemin and iodo-hemin systems, have encouraged us to use the Hartree-Fock Roothaan

  15. Characterization of vanadium oxide catalysts supported on TiO{sub 2}-ZrO{sub 2} by solid-state {sup 51}V and {sup 1}H NMR spectroscopy

    SciTech Connect

    Reddy, B.M.; Reddy, E.P.; Srinivas, S.T.

    1992-08-20

    A series of TiO{sub 2}-ZrO{sub 2} mixed oxide supported vanadia catalysts with various V{sub 2}O{sub 5} loadings ranging from 1 to 16 wt % were prepared by a wet impregnation method and were characterized by means of solid-state {sup 51}V and {sup 1}H NMR spectroscopic techniques. The solid-state {sup 51}V NMR spectra of V{sub 2}O{sub 5}/TiO{sub 2}-ZrO{sub 2} catalysts reveal the existence of two types of dispersed surface vanadium oxide complexes in a tetrahedral oxygen environment at lower vanadium loadings adn a third three-dimensional crystalline V{sub 2}O{sub 5} in distorted octahedral environment at higher vanadium contents. The proton NMR results provide evidence for the existence of metal oxide support interaction through the support hydroxyl groups. 33 regs., 4 figs.

  16. Magnetic fluctuations and possible formation of a spin-singlet cluster under pressure in the heavy-fermion spinel LiV2O4 probed by 7Li and 51V NMR

    NASA Astrophysics Data System (ADS)

    Takeda, Hikaru; Kato, Yusuke; Yoshimura, Masahiro; Shimizu, Yasuhiro; Itoh, Masayuki; Niitaka, Seiji; Takagi, Hidenori

    2015-07-01

    7Li and 51V NMR measurements up to 9.8 GPa have been made to elucidate local magnetic properties of a heavy-fermion spinel oxide LiV2O4 which undergoes a metal-insulator transition above ˜7 GPa. The temperature T and pressure P dependences of the 7Li and 51V Knight shifts and the nuclear spin-lattice relaxation rates 1 /T1 show that in the metallic phase, there is a crossover from a high-T region with weak ferromagnetic fluctuations to a low-T one with antiferromagnetic (AFM) fluctuations. The AFM fluctuations are enhanced below 20 K and 1.5 GPa, where a heavy Fermi-liquid state with the modified Korringa relation is formed. The evolution of the magnetic fluctuations is discussed from the aspect of the competition among several magnetic interactions. Above PMI˜6.7 GPa, we find the coexistence of metallic and insulating phases due to the first-order metal-insulator transition. The 7Li and 51V NMR spectra coming from the insulating phase have T -independent small Knight shifts and 7(1 /T1 ) with the thermally activated T dependence, indicating the formation of a spin-singlet cluster. We propose a model of a spin-singlet tetramer as discussed in geometrically frustrated materials.

  17. Hyperfine resonances in metastable ^129Xe discharge cells

    NASA Astrophysics Data System (ADS)

    Morgan, Steven W.; Xia, Tian; Jau, Yuan-Yu; Happer, William

    2008-05-01

    We have measured the hyperfine resonance linewidths of metastable ^129Xe in electrodeless rf discharge cells. The linewidths on the order of 10 kHz for Xe pressures of a few millitorr are dominated by collisions with other Xe atoms and no buffer gases are present. Additional contributions come from collisions with the walls as well as with impurities which may be drawn off the cell walls due to the harsh plasma environment. If used for small atomic clocks, metastable noble gases could require less power and would be relatively insensitive to temperature variations when compared with alkali metal atoms.

  18. Measurement of isotope shifts and hyperfine structure in Zr II

    NASA Astrophysics Data System (ADS)

    Rosner, S. D.; Holt, R. A.

    2016-06-01

    We have applied fast-ion-beam laser-fluorescence spectroscopy to measure the isotope shifts (IS) of 51 optical transitions in the wavelength range 420.6–461.4 nm and the hyperfine structures (hfs) of 11 even parity and 30 odd parity levels in Zr II. The IS and many of the hfs measurements are the first for these transitions and levels. These atomic data are very important for astrophysical studies of chemical abundances, allowing correction for saturation and the effects of blended lines. They also provide important constraints on stellar diffusion modeling and provide a benchmark for theoretical atomic structure calculations.

  19. Hyperfine magnetic field in Au2MnIn

    SciTech Connect

    Saleh, N.S.; Jha, S.; Julian, G.M.

    1985-01-01

    The hyperfine magnetic field (hmf) at nonmagnetic impurity Cd in the Heusler alloy Au2MnIn has been measured by the Time Differential Perturbed Angular Correlation (TDPAC) technique. The measurement utilized the 84-nsec 247 kev state in Cd-111 populated in the decay of 2.8-d In-111. The alloy was prepared by heating together in argon atmoshpere stoichiometric amounts of the constituents. The hmf at the Cd site was measured as 155 plus or minus 3 kG at 77 K. 5 references.

  20. Single pion contribution to the hyperfine splitting in muonic hydrogen

    NASA Astrophysics Data System (ADS)

    Huong, Nguyen Thu; Kou, Emi; Moussallam, Bachir

    2016-06-01

    A detailed discussion of the long-range one-pion exchange (Yukawa potential) contribution to the 2 S hyperfine splitting in muonic hydrogen, which had, until recently, been disregarded, is presented. We evaluate the relevant vertex amplitudes, in particular π0μ+μ-, combining low energy chiral expansions together with experimental data on π0 and η decays into two leptons. A value of Δ EHFSπ=-(0.09 ±0.06 ) μ eV is obtained for this contribution.

  1. Hyperfine-structure-induced purely long-range molecules.

    PubMed

    Enomoto, Katsunari; Kitagawa, Masaaki; Tojo, Satoshi; Takahashi, Yoshiro

    2008-03-28

    We have experimentally observed and theoretically identified a novel class of purely long-range molecules. This novel purely long-range state is formed due to a very weak hyperfine interaction that is usually treated only as a small perturbation in molecular spectra. Photoassociation spectroscopy of ultracold ytterbium (171Yb) atoms with the 1S0-3P1 intercombination transition presents clear identification of molecular states and the shallowest molecular potential depth of about 750 MHz among the purely long-range molecules ever observed. PMID:18517858

  2. Hyperfine interactions at nitrogen interstitial defects in diamond

    NASA Astrophysics Data System (ADS)

    Atumi, M. K.; Goss, J. P.; Briddon, P. R.; Shrif, F. E.; Rayson, M. J.

    2013-02-01

    Diamond has many extreme physical properties and it can be used in a wide range of applications. In particular it is a highly effective particle detection material, where radiation damage is an important consideration. The WAR9 and WAR10 are electron paramagnetic resonance centres seen in irradiated, nitrogen-containing diamond. These S = 1/2 defects have C2v and C1h symmetry, respectively, and the experimental spectra have been interpreted as arising from nitrogen split-interstitial centres. Based upon the experimental and theoretical understanding of interstitial nitrogen defect structures, the AIMPRO density functional code has been used to assess the assignments for the structures of WAR9 and WAR10. Although the calculated hyperfine interaction tensors are consistent with the measured values for WAR9, the thermal stability renders the assignment problematic. The model for the WAR10 centre yields principal directions of the hyperfine tensor at variance with observation. Alternative models for both centres are discussed in this paper, but no convincing structures have been found.

  3. Zeeman effects in the hyperfine structure of atomic iodine photodissociation laser emission.

    NASA Technical Reports Server (NTRS)

    Hwang, W. C.; Kasper, J. V. V.

    1972-01-01

    Observation of hyperfine structure in laser emission from CF3I and C2F5I photodissociation lasers. Constant magnetic fields affect the time behavior of the emission by changing the relative gains of the hyperfine transitions. Time-varying fields usually present in photodissociation lasers further complicate the emission.

  4. Vacuum-polarization contribution to the hyperfine-structure splitting of hydrogenlike atoms

    SciTech Connect

    Schneider, S.M.; Greiner, W. ); Soff, G. )

    1994-07-01

    A calculation of the vacuum-polarization contribution to the hyperfine splitting for hydrogenlike atoms is presented. The extended nuclear charge distribution is taken into account. For the experimentally interesting case [sup 209]Bi[sup 82+] we predict a [Delta][lambda]=[minus]1.6 nm shift for the transition wavelength of the ground-state hyperfine splitting.

  5. Anisotropy of hyperfine interactions as a tool for interpretation of NMR spectra in magnetic materials.

    PubMed

    Chlan, V; Stěpánková, H; Rezníček, R; Novák, P

    2011-07-01

    Approach for interpretation of nuclear magnetic resonance (NMR) spectra in magnetic materials is presented, consisting in employing the anisotropy of hyperfine interaction. The anisotropic parts of hyperfine magnetic fields on (57)Fe nuclei are calculated ab initio for a model example of lithium ferrite and utilized to assign the experimental NMR spectral lines to iron sites in the crystal structure. PMID:21536415

  6. Bottomonium spectrum at order v{sup 6} from domain-wall lattice QCD: Precise results for hyperfine splittings

    SciTech Connect

    Meinel, Stefan

    2010-12-01

    The bottomonium spectrum is computed in dynamical 2+1 flavor lattice QCD, using nonrelativistic QCD for the b quarks. The main calculations in this work are based on gauge field ensembles generated by the RBC and UKQCD Collaborations with the Iwasaki action for the gluons and a domain-wall action for the sea quarks. Lattice spacing values of approximately 0.08 fm and 0.11 fm are used, and simultaneous chiral extrapolations to the physical pion mass are performed. As a test for gluon-discretization errors, the calculations are repeated on two ensembles generated by the MILC Collaboration with the Luescher-Weisz gauge action. Gluon-discretization errors are also studied in a lattice potential model using perturbation theory for four different gauge actions. The nonperturbative lattice QCD results for the radial and orbital bottomonium energy splittings obtained from the RBC/UKQCD ensembles are found to be in excellent agreement with experiment. To get accurate results for spin splittings, the spin-dependent order-v{sup 6} terms are included in the nonrelativistic QCD action, and suitable ratios are calculated such that most of the unknown radiative corrections cancel. The cancellation of radiative corrections is verified explicitly by repeating the calculations with different values of the couplings in the nonrelativistic QCD action. Using the lattice ratios of the S-wave hyperfine and the 1P tensor splitting, and the experimental result for the 1P tensor splitting, the 1S hyperfine splitting is found to be 60.3{+-}5.5{sub stat{+-}}5.0{sub syst{+-}}2.1{sub exp} MeV, and the 2S hyperfine splitting is predicted to be 23.5{+-}4.1{sub stat{+-}}2.1{sub syst{+-}}0.8{sub exp} MeV.

  7. Changes of charge radii and hyperfine interactions of the Dy isotopes

    NASA Astrophysics Data System (ADS)

    Clark, D. L.; Greenlees, G. W.

    1982-10-01

    A continuous wave dye laser and a thermal atomic beam were used to measure the optical isotope shifts and hyperfine splittings for the 5547 Å, 5639 Å, 5652 Å, 5974 Å, and the 5989 Å transition of the seven stable isotopes of dysprosium. The hyperfine splitting of the odd-A isotopes has been analyzed using the formalism of Sanders and Beck and the hyperfine anomaly has been extracted. Comparison with calculations using Nilsson wave functions is presented. The isotope shift measurements have been analyzed with published electronic and muonic x-ray isotope shifts to yield δ values and some estimates of the specific mass shift constant. NUCLEAR STRUCTURE 156-164Dy. Measured optical isotope shifts and hyperfine splittings. Deduced δ, A(4f126s 6p), B(4f126s 6p), and the hyperfine anomaly. Laser spectroscopy on atomic beams.

  8. Resolution of hyperfine transitions in metastable 83Kr using electromagnetically induced transparency

    NASA Astrophysics Data System (ADS)

    Kale, Y. B.; Mishra, S. R.; Tiwari, V. B.; Singh, S.; Rawat, H. S.

    2015-05-01

    Narrow linewidth signals of electromagnetically induced transparency (EIT) in the metastable 83Kr have been observed. Various hyperfine transitions in the 4 p55 s [3/2 ] 2 to 4 p55 p [5/2 ] 3 manifolds of 83Kr have been identified through the experimentally observed EIT signals. Some unresolved or poorly resolved hyperfine transitions in saturated absorption spectroscopy (SAS) are clearly resolved in the present work. Using the spectral separation of these EIT identified hyperfine transitions, the magnetic hyperfine constant (A ) and the electric quadrupole hyperfine constant (B ) are determined with improved accuracy for 4 p55 s [3/2 ] 2 and 4 p55 p [5/2 ] 3 manifolds.

  9. The effects of hyperfine interactions on collisions between optically trapped atoms

    SciTech Connect

    Walker, T.; Hoffmann, D.; Peters, M.; Tobiason, J.

    1993-12-01

    The authors report measurements of excited state collision rates of optically trapped {sup 85}Rb and {sup 87}Rb. The collision rates have been measured in the vicinity of the P{sub 3/2} and P{sub 1/2} states of both isotopes. By studying the collision rates as a function of the frequency of light used to cause the collisions, they obtain collision spectra that reveal the importance of hyperfine interactions on the collision dynamics. In certain frequency ranges the collision rates for the two isotopes are nearly identical, while in others they find substantially reduced rates for {sup 87}Rb (large hyperfine interaction) as compared to {sup 85}Rb (small hyperfine interaction). For the P{sub 1/2} states, where hyperfine splittings are large compared to the characteristic frequency scales for these collisions, the shapes of the spectra more closely correspond to those expected from simple models that neglect hyperfine interactions.

  10. Singlet-triplet electron scattering admixture due to fine- and hyper-fine interactions in Cs Rydberg molecules

    NASA Astrophysics Data System (ADS)

    Markson, Samuel; Rittenhouse, Seth; Sadeghpour, Hossein

    2016-05-01

    We will present the admixture of singlet electron scattering into the more dominant triplet scattering in the formation of ultracold Cs Rydberg molecules excited into non-zero electronic angular momentum states. This admixture comes about due to both spin-orbit (SO) coupling in the Rydberg atom as well as the hyperfine (HF) coupling in the ground state atom. In Cs, the Rydberg SO and ground HF interactions are on par. The interaction between the Rydberg electron and the ground state atom includes both s-wave and p-wave scattering components which can cause additional mixing of electronic Rydberg states in the bound molecules. We intend to apply the formalism to Rydberg excitation in Cs in p and d states and will give a progress report at the meeting.

  11. First-principles calculations within periodic boundary conditions of the NMR shielding tensor for a transition metal nucleus in a solid state system: The example of 51V in AlVO4.

    PubMed

    Truflandier, L; Paris, M; Payen, C; Boucher, F

    2006-11-01

    We present the first density functional theory based calculations of NMR shielding parameters for a transition metal nucleus using periodic boundary conditions. These calculations employ the gauge-including projected augmented-wave pseudopotential approach. The quality of this method is discussed by comparing experimental and calculated chemical shift tensor eigenvalues for the quadrupolar 51V nucleus in the diamagnetic solid-state compound AlVO4. Furthermore, the combination of shielding tensor with fast and accurate projector augmented-wave electric field gradient tensor calculations allows us to determine the relative orientation of these two tensors. PMID:17064085

  12. The magnetic and hyperfine properties of iron in silicon carbide

    NASA Astrophysics Data System (ADS)

    Elzain, M.; Al-Harthi, S. H.; Gismelseed, A.; Al-Rawas, A.; Yousif, A.; Widatallah, H.; Al-Barwani, M.

    2014-04-01

    The magnetic and hyperfine properties of iron impurities in 3C- and 6H- silicon-carbide are calculated using the abinitio method of full-potential linear-augmented-plane-waves. The iron atoms are introduced at substitutional carbon, Fe C , and silicon, Fe Si , sites as well as at the tetrahedral interstitial sites with four nearest neighbours carbon atoms, Fe I (C), and four nearest neighbours silicon atoms, Fe I (Si). The effect of introducing vacancies at the neighbours of these sites is also studied. Fe atoms with complete neighbors substituted at Si or C sites are found to be nonmagnetic, while Fe atoms at interstitial sites are magnetic. Introduction of a vacancy at a neighboring site reverse the picture.

  13. Muon hyperfine fields in iron and its dilute alloys

    NASA Technical Reports Server (NTRS)

    Stronach, C. E.; Squire, K. R.; Arrott, A. S.; Patterson, B. D.; Heinrich, B.; Lankford, W. F.; Fiory, A. T.; Kossler, W. J.; Singh, J. J.

    1981-01-01

    The temperature dependence of the interstitial magnetic field, B, as determined by the rotation of the spin of the muon, has been measured for dilute polycrystalline iron alloys with Mo, Ti, and Nb additions over a temperature range of 240 to 633 K. In all cases the behaviors differ from one another and from the Fe(Al) alloys previously studied. B, which is negative with respect to the magnetization, is increased in magnitude by Al and Mo, and decreased greatly by Ti. The addition of Nb creates a two-phase alloy from which the role of heterogeneity and/or strain on B in iron can be assessed. If the temperature dependence of the hyperfine field extracted from B for Fe(Mo) alloys is interpreted on the model previously used to discuss the Fe(Al) data, then the muon must be attracted to the Mo atom while repelled by the Al atoms as the temperature decreases.

  14. Frequency shift of hyperfine transitions due to blackbody radiation

    SciTech Connect

    Angstmann, E. J.; Dzuba, V. A.; Flambaum, V. V.

    2006-08-15

    We have performed calculations of the size of the frequency shift induced by a static electric field on the clock transition frequencies of the hyperfine splitting in Yb{sup +}, Rb, Cs, Ba{sup +}, and Hg{sup +}. The calculations are used to find the frequency shifts due to blackbody radiation which are needed for accurate frequency measurements and improvements of the limits on variation of the fine-structure constant {alpha}. Our result for Cs [{delta}{nu}/E{sup 2}=-2.26(2)x10{sup -10}Hz/(V/m){sup 2}] is in good agreement with early measurements and ab initio calculations. We present arguments against recent claims that the actual value might be smaller. The difference ({approx}10%) is due to the contribution of the continuum spectrum in the sum over intermediate states.

  15. A source of antihydrogen for in-flight hyperfine spectroscopy

    PubMed Central

    Kuroda, N.; Ulmer, S.; Murtagh, D. J.; Van Gorp, S.; Nagata, Y.; Diermaier, M.; Federmann, S.; Leali, M.; Malbrunot, C.; Mascagna, V.; Massiczek, O.; Michishio, K.; Mizutani, T.; Mohri, A.; Nagahama, H.; Ohtsuka, M.; Radics, B.; Sakurai, S.; Sauerzopf, C.; Suzuki, K.; Tajima, M.; Torii, H. A.; Venturelli, L.; Wu¨nschek, B.; Zmeskal, J.; Zurlo, N.; Higaki, H.; Kanai, Y.; Lodi Rizzini, E.; Nagashima, Y.; Matsuda, Y.; Widmann, E.; Yamazaki, Y.

    2014-01-01

    Antihydrogen, a positron bound to an antiproton, is the simplest antiatom. Its counterpart—hydrogen—is one of the most precisely investigated and best understood systems in physics research. High-resolution comparisons of both systems provide sensitive tests of CPT symmetry, which is the most fundamental symmetry in the Standard Model of elementary particle physics. Any measured difference would point to CPT violation and thus to new physics. Here we report the development of an antihydrogen source using a cusp trap for in-flight spectroscopy. A total of 80 antihydrogen atoms are unambiguously detected 2.7 m downstream of the production region, where perturbing residual magnetic fields are small. This is a major step towards precision spectroscopy of the ground-state hyperfine splitting of antihydrogen using Rabi-like beam spectroscopy. PMID:24448273

  16. Opto-Electronic Oscillator Stabilized By A Hyperfine Atomic Transition

    NASA Technical Reports Server (NTRS)

    Strekalov, Dmitry; Aveline, David; Matsko, Andrey B.; Thompson, Robert; Yu, Nan

    2004-01-01

    Opto-electronic oscillator (OEO) is a closed-loop system with part of the loop is implemented by an optical beam, and the rest by RF circuitry. The technological advantage of this approach over traditional all-RF loops in the gigahertz range comes from the that frequency filtering can be done far more efficiently in the optical range with compact, low power, and have superior stability. In this work, we report our preliminary results on using the phenomenon of coherent population trapping in (87) Rb vapor as an optical filter. Such a filter allows us to stabilize the OEO at the hyperfine splitting frequency of rubidium, thus implementing a novel type of frequency standard.

  17. Hyperfine-induced spin relaxation of a diffusively moving carrier in low dimensions: Implications for spin transport in organic semiconductors

    NASA Astrophysics Data System (ADS)

    Mkhitaryan, V. V.; Dobrovitski, V. V.

    2015-08-01

    The hyperfine coupling between the spin of a charge carrier and the nuclear spin bath is a predominant channel for the carrier spin relaxation in many organic semiconductors. We theoretically investigate the hyperfine-induced spin relaxation of a carrier performing a random walk on a d -dimensional regular lattice, in a transport regime typical for organic semiconductors. We show that in d =1 and 2, the time dependence of the space-integrated spin polarization P (t ) is dominated by a superexponential decay, crossing over to a stretched-exponential tail at long times. The faster decay is attributed to multiple self-intersections (returns) of the random-walk trajectories, which occur more often in lower dimensions. We also show, analytically and numerically, that the returns lead to sensitivity of P (t ) to external electric and magnetic fields, and this sensitivity strongly depends on dimensionality of the system (d =1 versus d =3 ). Furthermore, we investigate in detail the coordinate dependence of the time-integrated spin polarization σ (r ) , which can be probed in the spin-transport experiments with spin-polarized electrodes. We demonstrate that, while σ (r ) is essentially exponential, the effect of multiple self-intersections can be identified in transport measurements from the strong dependence of the spin-decay length on the external magnetic and electric fields.

  18. Magnetic dipole hyperfine interactions in {sup 137}Ba{sup +} and the accuracies of the neutral weak interaction matrix elements

    SciTech Connect

    Sahoo, Bijaya K.; Gopakumar, Geetha; Chaudhuri, Rajat K.; Das, B.P.; Merlitz, Holger; Mahapatra, Uttam Sinha; Mukherjee, Debashis

    2003-10-01

    The relativistic coupled-cluster method is applied to calculate the magnetic dipole hyperfine constant 'A' of the 6s{sub 1/2}, 6p{sub 1/2}, 6p{sub 3/2}, and 5d{sub 3/2} states of singly ionized barium. After the inclusion of two-body correlation effects into the computation of the hyperfine matrix elements, the accuracy of the obtained values was significantly increased compared to earlier computations. Based on these numbers and earlier calculations of the electric dipole transitions and excitation energies, an estimate for the accuracy of the vertical bar [5p{sup 6}]6s{sub 1/2}>{yields} vertical bar [5p{sup 6}]5d{sub 3/2}> parity-nonconserving electric dipole transition amplitude is carried out. The results suggest that for the first time, to our knowledge, a precision of better than 1% is feasible for this transition amplitude.

  19. Hyperfine-induced spin relaxation of a diffusively moving carrier in low dimensions: Implications for spin transport in organic semiconductors

    SciTech Connect

    Mkhitaryan, V. V.; Dobrovitski, V. V.

    2015-08-24

    The hyperfine coupling between the spin of a charge carrier and the nuclear spin bath is a predominant channel for the carrier spin relaxation in many organic semiconductors. We theoretically investigate the hyperfine-induced spin relaxation of a carrier performing a random walk on a d-dimensional regular lattice, in a transport regime typical for organic semiconductors. We show that in d=1 and 2, the time dependence of the space-integrated spin polarization P(t) is dominated by a superexponential decay, crossing over to a stretched-exponential tail at long times. The faster decay is attributed to multiple self-intersections (returns) of the random-walk trajectories, which occur more often in lower dimensions. We also show, analytically and numerically, that the returns lead to sensitivity of P(t) to external electric and magnetic fields, and this sensitivity strongly depends on dimensionality of the system (d=1 versus d=3). We investigate in detail the coordinate dependence of the time-integrated spin polarization σ(r), which can be probed in the spin-transport experiments with spin-polarized electrodes. We also demonstrate that, while σ(r) is essentially exponential, the effect of multiple self-intersections can be identified in transport measurements from the strong dependence of the spin-decay length on the external magnetic and electric fields.

  20. Hyperfine-induced spin relaxation of a diffusively moving carrier in low dimensions: Implications for spin transport in organic semiconductors

    DOE PAGESBeta

    Mkhitaryan, V. V.; Dobrovitski, V. V.

    2015-08-24

    The hyperfine coupling between the spin of a charge carrier and the nuclear spin bath is a predominant channel for the carrier spin relaxation in many organic semiconductors. We theoretically investigate the hyperfine-induced spin relaxation of a carrier performing a random walk on a d-dimensional regular lattice, in a transport regime typical for organic semiconductors. We show that in d=1 and 2, the time dependence of the space-integrated spin polarization P(t) is dominated by a superexponential decay, crossing over to a stretched-exponential tail at long times. The faster decay is attributed to multiple self-intersections (returns) of the random-walk trajectories, whichmore » occur more often in lower dimensions. We also show, analytically and numerically, that the returns lead to sensitivity of P(t) to external electric and magnetic fields, and this sensitivity strongly depends on dimensionality of the system (d=1 versus d=3). We investigate in detail the coordinate dependence of the time-integrated spin polarization σ(r), which can be probed in the spin-transport experiments with spin-polarized electrodes. We also demonstrate that, while σ(r) is essentially exponential, the effect of multiple self-intersections can be identified in transport measurements from the strong dependence of the spin-decay length on the external magnetic and electric fields.« less

  1. The hyperfine interaction in 171YbF

    NASA Astrophysics Data System (ADS)

    Mawhorter, Richard; Glassman, Zachary; Grabow, Jens-Uwe; Le, Anh; Steimle, Timothy

    2014-05-01

    Motivated by recent further improvements in determining the upper limit for the CP-violating electric dipole moment of the electron (eEDM), the pure rotational spectrum of the open shell molecule ytterbium fluoride, 171YbF, in the X2Σ+ (v = 0) state has been recorded using Fourier transform microwave (FTMW) spectroscopy and pump/probe microwave optical double resonance (PPMODR) spectroscopy. The pure rotational spectra and precisely measured splittings in the (0,0) A2Π1 / 2 <-- X2Σ+ band were analyzed to produce an improved set of fine and magnetic hyperfine parameters for the X2Σ+ (v = 0) state of 171YbF. These will be used in conjunction with new FTMW data for 170 , 172 , 174 , 176YbF in a multi-isotope Dunham Uij fit to provide stable predictions for the rotational spectrum of 173YbF. Observing the nuclear electric quadrupole hyperfine structure of this isotopologue will help characterize the critical electric field at the heavy atom nucleus. This provides an important benchmark for the molecular wavefunctions used to calculate the effective internal field strength in this and other species, which in turn go into determining the eEDM upper limit. Similar work with the isotopologues of PbF, where nearby states of opposite parity have already been found, will also benefit proposed anapole moment and variation of fundamental constants studies. TS & AL acknowledge support from NSF CHE-1265885, JUG from DFG & Land Niedersachsen, RM from DAAD & Pomona College, and ZG from the Sherman Fairchild Foundation.

  2. Hyperfine interactions in Ho(Fe1-xCox)2 compounds at 77 K

    NASA Astrophysics Data System (ADS)

    Bednarski, M.; Stoch, P.; Zachariasz, P.; Pszczoła, J.; Bodnar, W.; Suwalski, J.

    2011-01-01

    Synthesized, x-ray studied Ho(Fe1-xCox)2 compounds (x= 0-1) have a pure cubic Fd3m, C15, MgCu2-type crystal phase. The unit cell parameter decreases nonlinearly with the composition parameter x. Mössbauer effect spectra collected at 77 K for the Ho(Fe1-xCox)2 series were composed of a number of locally originated subspectra due to random Fe/Co nearest neighbourhoods. Hyperfine interaction parameters, i.e. the isomer shift, the magnetic hyperfine field and the quadrupole interaction parameter, were determined from the fitting procedure of the spectra for the individual nearest neighbourhoods and also as average values for the sample as bulk. As a result of Fe/Co substitution, Slater-Pauling-type dependences for magnetic hyperfine fields corresponding to both the local area and the sample as bulk were observed. A correlation between the local magnetic hyperfine fields and the average magnetic hyperfine fields was noticed, and this was related to weak and strong ferromagnetism of the transition metal sublattice. The obtained magnetic hyperfine fields were compared to analogous data known for compounds with other rare earths. A numerical formula for describing the magnetic hyperfine field as a function of the composition parameter x and rare earth spin S was proposed.

  3. Fine- and hyperfine-structure effects in molecular photoionization. I. General theory and direct photoionization.

    PubMed

    Germann, Matthias; Willitsch, Stefan

    2016-07-28

    We develop a model for predicting fine- and hyperfine intensities in the direct photoionization of molecules based on the separability of electron and nuclear spin states from vibrational-electronic states. Using spherical tensor algebra, we derive highly symmetrized forms of the squared photoionization dipole matrix elements from which we derive the salient selection and propensity rules for fine- and hyperfine resolved photoionizing transitions. Our theoretical results are validated by the analysis of the fine-structure resolved photoelectron spectrum of O2 reported by Palm and Merkt [Phys. Rev. Lett. 81, 1385 (1998)] and are used for predicting hyperfine populations of molecular ions produced by photoionization. PMID:27475368

  4. Sub-Doppler Spectra of Infrared Hyperfine Transitions of Nitric Oxide Using a Pulse Modulated Quantum Cascade Laser: Rapid Passage, Free Induction Decay and the AC Stark Effect

    SciTech Connect

    Duxbury, Geoffrey; Kelly, James F.; Blake, Thomas A.; Langford, Nigel

    2012-05-07

    Using a low power, rapid (nsec) pulse-modulated quantum cascade (QC) laser, collective coherent effects in the 5 {micro}m spectrum of nitric oxide have been demonstrated by the observation of sub-Doppler hyperfine splitting and also Autler-Townes splitting of Doppler broadened lines. For nitrous oxide, experiments and model calculations have demonstrated that two main effects occur with ulsemodulated (chirped) quantum cascade lasers: free induction decay signals, and signals induced by rapid passage during the laser chirp. In the open shell molecule, NO, in which both {Lambda}-doubling splitting and hyperfine structure occur, laser field-induced coupling between the hyperfine levels of the two {Lambda}-doublet components can induce a large AC Stark effect. This may be observed as sub-Doppler structure, field-induced splittings, or Autler-Townes splitting of a Doppler broadened line. These represent an extension of the types of behaviour observed in the closed shell molecule nitrous oxide, using the same apparatus, when probed with an 8 {micro}m QC laser.

  5. On the origin of the hyperfine structure in the photoinduced EPR spectrum of [Pt(en) 2]Pt(en) 2Cl 2](ClO 4) 4

    NASA Astrophysics Data System (ADS)

    Arrington, C. A.; Unkefer, C. J.; Donohoe, R. J.; Huckett, S. C.; Kurita, S.; Swanson, B. I.

    1992-12-01

    The nitrogen isotope dependence of the EPR spectrum of the photoinduced paramagnetic defects in the halide-bridged platinum linear chain complex [Pt(en) 2][Pt(en) 2Cl 2](ClO 4) 4 (en = ethylenediamine) has been studied in order to clarify the origin of the 16G hyperfine structure which is superimposed on the 180G hyperfine pattern due to two equivalent Pt nuclei. An earlier study attributed the 16G pattern to the equatorial chelating nitrogens: however, we find that the EPR spectrum obtained for the 15N-substituted species is identical to that obtained for the normal isotopic species, demonstrating that these off-axis nitrogens are not the origin of this splitting. On the basis of this observation and simulations of the EPR spectrum, we attribute the 16G hyperfine pattern to coupling with three or more chlorine nuclei on the chain axis. The origin of the photoinduced paramagnetic defect in PtCl, whether polaronic or neutral kink soliton, is discussed in view of this new data. These results clearly demonstrate the importance of including halide orbitals in many-body models of the quasi-one-dimensional MX chain solids.

  6. Fine- and hyperfine-structure effects in molecular photoionization. II. Resonance-enhanced multiphoton ionization and hyperfine-selective generation of molecular cations.

    PubMed

    Germann, Matthias; Willitsch, Stefan

    2016-07-28

    Resonance-enhanced multiphoton ionization (REMPI) is a widely used technique for studying molecular photoionization and producing molecular cations for spectroscopy and dynamics studies. Here, we present a model for describing hyperfine-structure effects in the REMPI process and for predicting hyperfine populations in molecular ions produced by this method. This model is a generalization of our model for fine- and hyperfine-structure effects in one-photon ionization of molecules presented in Paper I [M. Germann and S. Willitsch, J. Chem. Phys. 145, 044314 (2016)]. This generalization is achieved by covering two main aspects: (1) treatment of the neutral bound-bound transition including the hyperfine structure that makes up the first step of the REMPI process and (2) modification of our ionization model to account for anisotropic populations resulting from this first excitation step. Our findings may be used for analyzing results from experiments with molecular ions produced by REMPI and may serve as a theoretical background for hyperfine-selective ionization experiments. PMID:27475369

  7. Fine- and hyperfine-structure effects in molecular photoionization. II. Resonance-enhanced multiphoton ionization and hyperfine-selective generation of molecular cations

    NASA Astrophysics Data System (ADS)

    Germann, Matthias; Willitsch, Stefan

    2016-07-01

    Resonance-enhanced multiphoton ionization (REMPI) is a widely used technique for studying molecular photoionization and producing molecular cations for spectroscopy and dynamics studies. Here, we present a model for describing hyperfine-structure effects in the REMPI process and for predicting hyperfine populations in molecular ions produced by this method. This model is a generalization of our model for fine- and hyperfine-structure effects in one-photon ionization of molecules presented in Paper I [M. Germann and S. Willitsch, J. Chem. Phys. 145, 044314 (2016)]. This generalization is achieved by covering two main aspects: (1) treatment of the neutral bound-bound transition including the hyperfine structure that makes up the first step of the REMPI process and (2) modification of our ionization model to account for anisotropic populations resulting from this first excitation step. Our findings may be used for analyzing results from experiments with molecular ions produced by REMPI and may serve as a theoretical background for hyperfine-selective ionization experiments.

  8. NMR Hyperfine Shifts in Blue Copper Proteins: A Quantum Chemical Investigation

    PubMed Central

    Zhang, Yong; Oldfield, Eric

    2009-01-01

    We present the results of the first quantum chemical investigations of 1H NMR hyperfine shifts in the blue copper proteins (BCPs): amicyanin, azurin, pseudoazurin, plastocyanin, stellacyanin, and rusticyanin. We find that very large structural models that incorporate extensive hydrogen bond networks, as well as geometry optimization, are required to reproduce the experimental NMR hyperfine shift results, the best theory vs experiment predictions having R2 = 0.94, a slope = 1.01, and a SD = 40.5 ppm (or ~4.7% of the overall ~860 ppm shift range). We also find interesting correlations between the hyperfine shifts and the bond and ring critical point properties computed using atoms-in-molecules theory, in addition to finding that hyperfine shifts can be well-predicted by using an empirical model, based on the geometry-optimized structures, which in the future should be of use in structure refinement. PMID:18314973

  9. Polarized 3He− ion source with hyperfine state selection

    SciTech Connect

    Dudnikov, V.; Morozov, Vasiliy; Dudnikov, A.

    2015-04-01

    High beam polarization is essential to the scientific productivity of a collider. Polarized 3He ions are an essential part of the nuclear physics programs at existing and future ion-ion and electron-ion colliders such as BNL's RHIC and eRHIC and JLab's ELIC. Ion sources with performance exceeding that achieved today are a key requirement for the development of these next generation high-luminosity high-polarization colliders. The development of high-intensity high-brightness arc-discharge ion sources at the Budker Institute of Nuclear Physics (BINP) has opened up an opportunity for realization of a new type of a polarized 3He− ion source. This report discusses a polarized 3He− ion source based on the large difference of extra-electron auto-detachment lifetimes of the different 3He− ion hyperfine states. The highest momentum state of 5/2 has the largest lifetime of τ ∼ 350 µs while the lower momentum states have lifetimes of τ ~ 10 µs. By producing 3He− ion beam composed of only the |5/2, ±5/2> hyperfine states and then quenching one of the states by an RF resonant field, 3He− beam polarization of 90% can be achieved. Such a method of polarized 3He− production has been considered before; however, due to low intensities of the He+ ion sources existing at that time, it was not possible to produce any interesting intensity of polarized 3He− ions. The high-brightness arc-discharge ion source developed at BINP can produce a high-brightness 3He+ beam with an intensity of up to 2 A allowing for selection of up to ∼1-4 mA of 3He− ions with ∼90% polarization. The high gas efficiency of an arc-discharge source is important due to the high cost of 3He gas. Some features of such a PIS as well as prototype designs are considered. An integrated 3He− ion source design providing high beam polarization could be prepared using existing BNL equipment with incorporation of new designs of the 1) arc discharge plasma generator, 2) extraction system, 3) charge

  10. Rotational Spectra in Service of Particle Physics - Zeeman & Hyperfine Effects

    NASA Astrophysics Data System (ADS)

    Mawhorter, Richard J.; Baum, Alexander L.; Glassmann, Zachary; Girodas, Benjamin; Sears, Trevor; Shafer-Ray, Neil E.; Alphei, Lukas; Grabow, Jens-Uwe

    2013-06-01

    Motivated by the ongoing search for the parity violating effects originated by an electron electric dipole moment (e-EDM) or a nuclear anapole moment,the rotational spectra of heavy atom diatomic radicals like, e.g., ^{2}Π_{1/2} PbF are studied at the unrivalled resolution offered by supersonic-jet Fourier transform microwave spectroscopy. Obtaining accurate information on such relativistically behaving systems wil be the key to provide a delicate test to the proposed theories in extension to the Standard Model of Physics. Employment of an MW method to hunt down these tiny effects, easily obscured by the linewidth inherent to other techniques, in rotational transitions is a promising approach to observe the tiny energy difference of terms that are degenerate without parity violation. Already before an experiment sensitive to parity violation, the exceptional resolution of the microwave time-domain technique can be exploited to provide accurate tests on the quantum chemical predictions that are part of the calculation of the anticipated e-EDM or anapole moment sensitivity of a given species since nuclear quadrupole and magnetic hyperfine effects in the rotational spectra are closely related. In our current experiment, transitions can be observed with 0.2 kHz accuracy for unblended lines over a range of 2 - 26.5 GHz. The observation of field dependent spectra (in magnetic fields up to 4 Gauss) allows for the determination of the two body fixed g-factors, G_{perp} and G_{allel} which can then be compared with recent theoretical values. YbF provides the current e-EDM upper limit. Although it is more sensitive to magnetic fields, the nuclear quadrupole hyperfine structure of ^{173}YbF constitutes a direct probe on the electric field gradient and thus can help characterize the critical electric field at the heavy atom nucleus. We will report on 14 GHz transitions for 3 of the less abundant even isotopologues of YbF as well as the ^{207}PbF analogue ^{171}YbF, important

  11. Temperature dependence of the magnetic hyperfine field at an s-p impurity diluted in RNi2

    NASA Astrophysics Data System (ADS)

    de Oliveira, A. L.; Chaves, C. M.; Oliveira, N. A. de; Troper, A.

    2016-03-01

    We study the formation of local magnetic moments and magnetic hyperfine fields at an s-p impurity diluted in intermetallic Laves phase compounds RNi2 (R=Nd, Sm, Gd, Tb, Dy) at finite temperatures. We start with a clean host and later the impurity is introduced. The host has two-coupled (R and Ni) sublattice Hubbard Hamiltonians but the Ni sublattice can be disregarded because its d band, being full, is magnetically ineffective. Also, the effect of the 4f electrons of R is represented by the polarization they produce on the d band. This leaves us with a lattice of effective rare earth R-ions with polarized electrons. For the dd electronic interaction we use the Hubbard-Stratonovich identity in a functional integral approach in the static saddle point approximation.

  12. Hyperfine structure of the S- and P-wave states of muonic deuterium

    NASA Astrophysics Data System (ADS)

    Martynenko, A. P.; Martynenko, G. A.; Sorokin, V. V.; Faustov, R. N.

    2016-03-01

    Corrections of order α5 and α6 to the hyperfine structure of the S- and P-wave states of muonic deuteriumwere calculated on the basis of the quasipotential approach in quantum electrodynamics. Relativistic corrections, vacuum-polarization and deuteron-structure effects, and recoil corrections were taken into account in this calculation. The resulting hyperfine-splitting values can be used in a comparison with experimental data obtained by the CREMA Collaboration.

  13. Dimensionless coordinates for simulations and theory of hyperfine interactions in materials

    NASA Astrophysics Data System (ADS)

    Evenson, William E.; Zacate, Matthew O.

    2010-04-01

    For problems involving simulations or theory of hyperfine interactions in materials, it is convenient to work in dimensionless coordinates of reasonable magnitude. Such a system is described here that constitutes a consistent and useful "natural" dimensionless unit system that simplifies point-charge approximations, scaling between different crystal structures, scaling charges of various defects in materials, and other computations involving hyperfine interactions. We present the proposed system with examples of its use for data analysis as well as for simulations and theory.

  14. Hyperfine field of einsteinium in iron and nuclear magnetic moment of Es254

    NASA Astrophysics Data System (ADS)

    Severijns, N.; Belyaev, A. A.; Erzinkyan, A. L.; Eversheim, P.-D.; Filimonov, V. T.; Golovko, V. V.; Gurevich, G. M.; Herzog, P.; Kraev, I. S.; Lukhanin, A. A.; Noga, V. I.; Parfenova, V. P.; Phalet, T.; Rusakov, A. V.; Tandecki, M.; Toporov, Yu. G.; Tramm, C.; Traykov, E.; Gorp, S. Van; Vyachin, V. N.; Wauters, F.; Zákoucký, D.; Zotov, E.

    2009-06-01

    The angular distributions of γ rays and α particles from oriented Bk250, Es253,254, and Fm255 nuclei were investigated to extract hyperfine interaction information for these actinide impurities in an iron host lattice. The hyperfine field of einsteinium in iron was found to be |Bhf(EsFe̲|)=396(32) T. With this value the magnetic moment of Es254 was then determined as |μ|=4.35(41)μN.

  15. Calculation of the hyperfine structure of the superheavy elements Z=119 and Z=120{sup +}

    SciTech Connect

    Dinh, T. H.; Dzuba, V. A.; Flambaum, V. V.

    2009-10-15

    The hyperfine-structure constants of the lowest s and p{sub 1/2} states of superheavy elements Z=119 and Z=120{sup +} are calculated using ab initio approach. Core polarization and dominating correlation effects are included to all orders. Breit and quantum electrodynamic effects are also considered. Similar calculations for Cs, Fr, Ba{sup +}, and Ra{sup +} are used to control the accuracy. The dependence of the hyperfine-structure constants on the nuclear radius is discussed.

  16. Hyperfine interactions in titanates: Study of orbital ordering and local magnetic properties

    SciTech Connect

    Agzamova, P. A. Leskova, Yu. V.; Nikiforov, A. E.

    2013-05-15

    Hyperfine magnetic fields induced on the nuclei of nonmagnetic ions {sup 139}La and {sup 89}Y in LaTiO{sub 3} and YTiO{sub 3}, respectively, have been microscopically calculated. The dependence of the hyperfine fields on the orbital and magnetic structures of the compounds under study has been analyzed. The comparative analysis of the calculated and known experimental data confirms the existence of the static orbital structure in lanthanum and yttrium titanates.

  17. Magnetic hyperfine interactions on Cd sites of the rare-earth cadmium compounds R Cd (R =Ce , Pr, Nd, Sm, Gd, Tb, Dy, Ho, and Er)

    NASA Astrophysics Data System (ADS)

    Cavalcante, F. H. M.; Leite Neto, O. F. L. S.; Saitovitch, H.; Cavalcante, J. T. P. D.; Carbonari, A. W.; Saxena, R. N.; Bosch-Santos, B.; Pereira, L. F. D.; Mestnik-Filho, J.; Forker, M.

    2016-08-01

    the indirect coupling is provided by the intra-atomic 4 f -5 d exchange and interatomic 5 d -5 d interaction between the spin-polarized 5 d electrons of neighboring R atoms. The ratio of the hyperfine fields of GdCd and GdCd2 scales with the number of nearest Gd neighbors. In the paramagnetic phases of the R Cd compounds, the PAC spectra indicate the presence of a broad distribution of weak quadrupole interactions suggesting a perturbation of the cubic CsCl symmetry of the Cd site, most probably due to chemical disorder of the R and Cd sublattices. A substantial interchange of R and Cd atoms is also reflected in the temperature dependence of the linewidth of the magnetic hyperfine interaction in the magnetically ordered phase of R Cd and GdCd2. Its critical increase towards the order temperature is evidence for a distribution of the order temperature with a width of about 10 K.

  18. The effects of hyperfine interactions on collisions between optically trapped atoms

    SciTech Connect

    Walker, T.; Feng, P.; Hoffmann, D.

    1993-05-01

    We report measurements of excited-state collision rates of optically trapped {sup 85}Rb and {sup 87}Rb. The collision rates have been measured in the vicinity of the P{sub 3/2} and P{sub 1/2} states of both isotopes. By studying the collision rates as a function of the frequency of light used to cause the collisions, we obtain collision spectra that reveal the importance of hyperfine interactions on the collision dynamics. In certain frequency ranges the spectra for the two isotopes are nearly identical, while in others we find substantially reduced rates for {sup 87}Rb (large hyperfine interaction) as compared to {sup 85}Rb (small hyperfine interaction). For the P{sub 1/2} states, where hyperfine splittings are large compared to the characteristic frequency scale for these collisions, the shapes of the spectra more closely correspond to those expected from simple models that neglect hyperfine interactions. Many of our observations can be qualitatively explained by our calculations of the long-range resonance potential curves including hyperfine interactions.

  19. Electron spin dephasing by hyperfine interaction with nuclei in quantum dots

    NASA Astrophysics Data System (ADS)

    Cywinski, Lukasz

    2010-03-01

    The problem of the dynamics of an electron spin coupled by hyperfine (hf) interaction to nuclear spins has been a focus of large theoretical attention, since the interaction with the nuclear bath is the most limiting decoherence mechanism in spin qubits based on quantum dots made of III-V materials. I will present a theory of pure dephasing decoherence which gives predictions for electron dynamics in narrowed state free induction decay, spin echo, and under higher order dynamical decoupling sequences [1,2]. In this theory we take advantage of the long-range character of hf-mediated interactions (which couple remote nuclei via virtual flip-flops with the electron spin), and we resum the leading terms in 1/N expansion of the decoherence time-evolution function (N being the large number of nuclei interacting appreciably with the electron spin). For the case of a thermal uncorrelated bath this approach is applicable as long as the electron Zeeman splitting is larger than the typical Overhauser shift of the electron energy (i.e. magnetic field must be larger than a few mT in a large GaAs dot). For the spin echo evolution we show that the dominant decoherence process at low fields is due to interactions between nuclei having different Zeeman energies (i.e. nuclei of As and two isotopes of Ga in GaAs). The robustness of this theory is verified by comparison with a numerical simulation of spin echo in a system with N = 20 nuclei. I will also discuss the application of our approach to singlet-triplet qubit in a double quantum dot. [4pt] [1] L. Cywinski, W.M. Witzel, and S. Das Sarma, Phys. Rev. Lett. 102, 057601 (2009). [0pt] [2] L. Cywinski, W.M. Witzel, and S. Das Sarma, Phys. Rev. B 79, 245314 (2009).

  20. Dynamic nuclear polarization in the hyperfine-field-dominant region

    NASA Astrophysics Data System (ADS)

    Lee, Seong-Joo; Shim, Jeong Hyun; Kim, Kiwoong; Yu, Kwon Kyu; Hwang, Seong-min

    2015-06-01

    Dynamic nuclear polarization (DNP) allows measuring enhanced nuclear magnetic resonance (NMR) signals. Though the efficiency of DNP has been known to increase at low fields, the usefulness of DNP has not been throughly investigated yet. Here, using a superconducting quantum interference device-based NMR system, we performed a series of DNP experiments with a nitroxide radical and measured DNP spectra at several magnetic fields down to sub-microtesla. In the DNP spectra, the large overlap of two peaks having opposite signs results in net enhancement factors, which are significantly lower than theoretical expectations [30] and nearly invariant with respect to magnetic fields below the Earth's field. The numerical analysis based on the radical's Hamiltonian provides qualitative explanations of such features. The net enhancement factor reached 325 at maximum experimentally, but our analysis reveals that the local enhancement factor at the center of the rf coil is 575, which is unaffected by detection schemes. We conclude that DNP in the hyperfine-field-dominant region yields sufficiently enhanced NMR signals at magnetic fields above 1 μ T.

  1. Precision measurement of muonium hyperfine splitting at J-PARC

    NASA Astrophysics Data System (ADS)

    Kanda, Sohtaro; J-PARC MuHFS Collaboration

    2014-09-01

    Muonium is the bound state of a positive muon and an electron. Because neither muon nor electron has internal structure, muonium's ground state hyperfine splitting (MuHFS) can be the most precise probe for the test of the bound state QED and for the determination of the ratio of magnetic moments of muon and proton. At J-PARC, we plan to perform a precision measurement of the MuHFS via microwave spectroscopy of muonium. Muonium is formed in Kr gas target and state transition between energy levels is induced by microwave resonance. Spectroscopy of the muonium states can be performed by measurement of positron asymmetry from muonium decay. Precision of the most recent experimental result (LAMPF1999) was mostly statistically limited. Hence, improved statistics is essential for higher precision of the measurement. Our goal is to improve accuracy by an order of magnitude compared to the most recent experiment. In order to achieve the goal, we utilize J-PARC's highest-intensity pulsed muon beam (expected intensity is 1 ×108μ+ / s), highly segmented positron detector with SiPM (Silicon PhotoMultiplier), and an online/offline muon beam profile monitor. In this presentation, we discuss the experimental overview and development status of each components.

  2. Hyperfine anomalies of HCN in cold dark clouds

    SciTech Connect

    Walmsley, C.M.; Churchwell, E.; Nash, A.; Fitzpatrick, E.

    1982-07-15

    We report observations of the J = 1..-->..0 line of HCN measured toward six positions in nearby low-temperature dark clouds. The measured relative intensities of the hyperfine components of the J = 1..-->..0 line are anomalous in that the F = 0..-->..1 transition is stronger than would be expected if all three components (F = 2..-->..1, F = 1..-->..1, F = 0..-->..1) had equal excitation temperatures. Differences of approximately 20% in the populations per sublevel of J = 1 could account for the observations. The results are in contrast to the situation observed in warmer molecular clouds associated with H II regions where the F = 1..-->..1 line is anomalously weak. The apparent overpopulation of J = 1, F = 0 in dark clouds may be related to the phenomenon observed in the J = 1..-->..0 transitions of HCO/sup +/ and HNC in the same objects where /sup 13/C substituted version of these species is found to be stronger than the /sup 12/C species.

  3. New Precise Measurement of the Hyperfine Splitting of Positronium

    SciTech Connect

    Ishida, A.

    2015-09-15

    Positronium (Ps) is an ideal system for precision test of bound state quantum electrodynamics. The hyperfine splitting (HFS) of the ground state of Ps, which is one of the most precisely tested quantity, has a large discrepancy of 16 ppm (4.5 σ) between previous experiments and theoretical calculation up to O(α{sup 3}lnα{sup −1}) and part of O(α{sup 3}) corrections. A new experiment which reduces possible systematic uncertainties of Ps thermalization effect and nonuniformity of magnetic field was performed. It revealed that the Ps thermalization effect was as large as 10 ± 2 ppm. Treating the thermalization effect correctly, a new result of 203.3942 ± 0.0016(stat., 8.0 ppm) ± 0.0013(sys., 6.4 ppm) GHz was obtained. This result is consistent with theory within 1.1 σ, whereas it disfavors the previous experimental result by 2.6 σ. It shows that the Ps thermalization effect is crucial for precision measurement of HFS. Future prospects for improved precision are briefly discussed.

  4. Spin-state transfer in laterally coupled quantum-dot chains with disorders

    NASA Astrophysics Data System (ADS)

    Yang, Song; Bayat, Abolfazl; Bose, Sougato

    2010-08-01

    Quantum dot arrays are a promising medium for transferring quantum information between two distant points without resorting to mobile qubits. Here we study the two most common disorders, namely hyperfine interaction and exchange coupling fluctuations, in quantum dot arrays and their effects on quantum communication through these chains. Our results show that the hyperfine interaction is more destructive than the exchange coupling fluctuations. The average optimal time for communication is not affected by any disorder in the system and our simulations show that antiferromagnetic chains are much more resistive than the ferromagnetic ones against both kind of disorders. Even when time modulation of a coupling and optimal control is employed to improve the transmission, the antiferromagnetic chain performs much better. We have assumed the quasistatic approximation for hyperfine interaction and time-dependent fluctuations in the exchange couplings. Particularly for studying exchange coupling fluctuations we have considered the static disorder, white noise, and 1/f noise.

  5. Double-Resonance Measurements of Isotope Shifts and Hyperfine Structure in Gd I with Hyperfine-State Selection in an Intermediate Level

    SciTech Connect

    Nortershauser, Wilfried; Bushaw, Bruce A.; Blaum, K.

    2000-06-01

    Isotope shifts and hyperfine structure have been measured in the 4f7 5d6s2 9D6 -- X9 D6 (;38 024. 9 cm-1) transition in atomic gadolinium using high- resolution resonance ionization mass spectroscopy. Excitation was performed as a resonance-enhanced two-photon transition with the 4f7 5d6s6p 9F7 state as an intermediate level. Selective population of hyperfine states in the first excitation step allowed assignment of all transitions in the complex hyperfine spectrum of the odd isotopes 155,157Gd and evaluation of the magnetic dipole and electric quadrupole hyperfine structure constants for the X 9D6 state. Measured values for the isotope shifts of all stable Gd isotopes have been used to derive specific mass shift and field shift factors. The obtained spectroscopic information leads to the conclusion that the X 9D6 state is a 4f75d6s8s configuration.

  6. 51V solid-state NMR and density functional theory studies of vanadium environments in V(V)O2 dipicolinic acid complexes

    NASA Astrophysics Data System (ADS)

    Bolte, Stephanie E.; Ooms, Kristopher J.; Polenova, Tatyana; Baruah, Bharat; Crans, Debbie C.; Smee, Jason J.

    2008-02-01

    V51 solid-state NMR and density functional theory (DFT) investigations are reported for a series of pentacoordinate dioxovanadium(V)-dipicolinate [V(V )O2-dipicolinate] and heptacoordinate aquahydroxylamidooxovanadium(V)-dipicolinate [V(V)O-dipicolinate] complexes. These compounds are of interest because of their potency as phosphatase inhibitors as well as their insulin enhancing properties and potential for the treatment of diabetes. Experimental solid-state NMR results show that the electric field gradient tensors in the V(V )O2-dipicolinate derivatives are affected significantly by substitution on the dipicolinate ring and range from 5.8to8.3MHz. The chemical shift anisotropies show less dramatic variations with respect to the ligand changes and range between -550 and -600ppm. To gain insights on the origins of the NMR parameters, DFT calculations were conducted for an extensive series of the V(V )O2- and V(V)O-dipicolinate complexes. To assess the level of theory required for the accurate calculation of the V51 NMR parameters, different functionals, basis sets, and structural models were explored in the DFT study. It is shown that the original x-ray crystallographic geometries, including all counterions and solvation water molecules within 5Å of the vanadium, lead to the most accurate results. The choice of the functional and the basis set at a high level of theory has a relatively minor impact on the outcome of the chemical shift anisotropy calculations; however, the use of large basis sets is necessary for accurate calculations of the quadrupole coupling constants for several compounds of the V(V )O2 series. These studies demonstrate that even though the vanadium compounds under investigations exhibit distorted trigonal bipyramidal coordination geometry, they have a "perfect" trigonal bipyramidal electronic environment. This observation could potentially explain why vanadate and vanadium(V) adducts are often recognized as potent transition state analogs.

  7. Semi-empirical predictions of even atomic energy levels and their hyperfine structure for the scandium atom

    SciTech Connect

    Dembczynski, J. . E-mail: Jerzy.Dembczynski@put.poznan.pl; Elantkowska, M.; Ruczkowski, J.; Stefanska, D.

    2007-01-15

    We report fine and hyperfine structure analysis of the system of even configurations of the Sc atom in a large multi-configuration basis. The complete energy scheme in the energy region up to about 50,000 cm{sup -1} has been established with the predicted values of the hyperfine cture constants A. The effects of the configuration interaction in the fine and hyperfine structure are discussed.

  8. The hyperfine structure in the rotational spectra of D{sub 2}{sup 17}O and HD{sup 17}O: Confirmation of the absolute nuclear magnetic shielding scale for oxygen

    SciTech Connect

    Puzzarini, Cristina Cazzoli, Gabriele; Harding, Michael E.; Vázquez, Juana; Gauss, Jürgen

    2015-03-28

    Guided by theoretical predictions, the hyperfine structures of the rotational spectra of mono- and bideuterated-water containing {sup 17}O have been experimentally investigated. To reach sub-Doppler resolution, required to resolve the hyperfine structure due to deuterium quadrupole coupling as well as to spin-rotation (SR) and dipolar spin-spin couplings, the Lamb-dip technique has been employed. The experimental investigation and in particular, the spectral analysis have been supported by high-level quantum-chemical computations employing coupled-cluster techniques and, for the first time, a complete experimental determination of the hyperfine parameters involved was possible. The experimentally determined {sup 17}O spin-rotation constants of D{sub 2}{sup 17}O and HD{sup 17}O were used to derive the paramagnetic part of the corresponding nuclear magnetic shielding constants. Together with the computed diamagnetic contributions as well as the vibrational and temperature corrections, the latter constants have been employed to confirm the oxygen nuclear magnetic shielding scale, recently established on the basis of spin-rotation data for H{sub 2}{sup 17}O [Puzzarini et al., J. Chem. Phys. 131, 234304 (2009)].

  9. Hyperfine structure in the X8, A[19.1]9 and B[21.68]8 states of HoF and X8 and A[15.6]9 state of HoCl

    NASA Astrophysics Data System (ADS)

    Dick, M. J.; Linton, C.; Adam, A. G.

    2015-02-01

    High resolution spectra of holmium monofluoride, HoF and holmium monochloride, HoCl, prepared in a laser ablation source, have been obtained using laser induced fluorescence. Spectra of the A[19.1]9-X8 0-0 and 1-0 and B[21.68]8-X8 0-0 bands of HoF and the A[15.6]9-X8 0-0 band of HoCl all show resolved hyperfine structure. Analysis of the spectra yielded magnetic hyperfine parameters, h = 0.2240(5), 0.2210(6), 0.2177(6) and 0.2488(5) cm-1 for the X (v = 0), A (v = 0 and 1) and B (v = 0) states of HoF and 0.2355(32) and 0.2448(29) cm-1 for the X (v = 0) and A (v = 0) states of HoCl, respectively. The following quadrupole coupling constants were obtained for the above six states; eQq0(HoF) = -0.0874(67), -0.0586(44), -0.0579(56), -0.0840(64) cm-1 and eQq0(HoCl) = -0.082(11), -0.060(11) cm-1. Comparison with previously determined values for HoO and HoS show that the ground state magnetic hyperfine structure in HoF and HoCl is entirely due to the Ho 4f electron and is consistent with the ground state, X8, configuration of Ho+{4f10(5I8)6s2}X- (X = F, Cl). Calculations of the ground state magnetic, h(X8), and quadrupole, eQq0(X8) hyperfine parameters from atomic hyperfine parameters are found to be consistent with the observed values for both molecules.

  10. 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.

  11. Hyperfine structure of the 4f85d6s2 configuration of the Tb atom

    NASA Astrophysics Data System (ADS)

    Furmann, B.; Stefanska, D.; Krzykowski, A.

    2015-09-01

    In this work, A and B hyperfine structure constants of electronic levels belonging to the configuration 4f85d6s2 of the terbium atom are presented, obtained via investigation of the hyperfine structure of 42 spectral lines, performed with the method of laser-induced fluorescence (LIF) in a hollow cathode discharge. Results for 14 of the investigated levels belonging to the configuration 4f85d6s2 were obtained for the first time. Also results concerning the hyperfine structure of 29 levels, involved in the transitions as upper levels, are presented. For these levels, almost all the results were obtained for the first time. On the basis of the results obtained within this work and those known from the literature, parametrization of the hyperfine structure was performed. The determined values of one-electron parameters for configuration 4f85d6s2 were compared to the values known from literature, determined so far on the basis of a much lower number of electronic levels. Values of relativistic radial integrals of the hyperfine structure for electrons 4f and 5d of the configuration 4f85d6s2 were calculated with the use of the MCDF code. The comparison of radial integrals calculated semi-empirically with those determined with MCDF method yielded an estimate of the values of configuration interaction parameters in the case of both magnetic dipole and electric quadrupole interactions of the terbium atom.

  12. Hyperfine structure of the hydroxyl free radical (OH) in electric and magnetic fields

    NASA Astrophysics Data System (ADS)

    Maeda, Kenji; Wall, Michael L.; Carr, Lincoln D.

    2015-05-01

    We investigate single-particle energy spectra of the hydroxyl free radical (OH) in the lowest electronic and rovibrational level under combined static electric and magnetic fields, as an example of heteronuclear polar diatomic molecules. In addition to the fine-structure interactions, the hyperfine interactions and centrifugal distortion effects are taken into account to yield the zero-field spectrum of the lowest 2Π3 / 2 manifold to an accuracy of less than 2kHz. We also examine level crossings and repulsions in the hyperfine structure induced by applied electric and magnetic fields. Compared to previous work, we found more than 10 percent reduction of the magnetic fields at level repulsions in the Zeeman spectrum subjected to a perpendicular electric field. In addition, we find new level repulsions, which we call Stark-induced hyperfine level repulsions, that require both an electric field and hyperfine structure. It is important to take into account hyperfine structure when we investigate physics of OH molecules at micro-Kelvin temperatures and below. This research was supported in part by AFOSR Grant No.FA9550-11-1-0224 and by the NSF under Grants PHY-1207881 and NSF PHY-1125915. We appreciate the Aspen Center for Physics, supported in part by the NSF Grant No.1066293, for hospitality.

  13. Long Hyperfine Coherence Time of Ultracold Fermionic 23 Na40 K Molecules

    NASA Astrophysics Data System (ADS)

    Park, Jee Woo; Yan, Zoe; Loh, Huanqian; Will, Sebastian; Zwierlein, Martin

    2016-05-01

    Ultracold molecules created and trapped at sub uK temperatures allow the full control of the molecule's external and internal degrees of freedom down to a single hyperfine state. In particular, an ensemble of molecules all initialized in a single rotational and hyperfine state can be prepared and be coherently addressed using microwave fields. In this talk, we report on the observation of long coherence time between two hyperfine states of fermionic 23 Na40 K molecules in the ro-vibronic ground state (v = 0 , J = 0). A direct two-photon microwave transition via the J = 1 state is used to prepare a superposition of two lowest hyperfine states of J = 0 , and we perform Ramsey spectroscopy as a direct probe of phase coherence between these states. The fermionic nature of the molecules and the lack of electronic angular momentum in the ro-vibronic ground state heavily suppress the decoherence from collisions and external fields, respectively, and we observe long coherence times upto 0.5 sec for this hyperfine superposition state. The observed long coherence time is a crucial step for applications of trapped dipolar molecules in quantum information processing schemes.

  14. 29Si-NMR study of magnetic anisotropy and hyperfine interactions in the uranium-bsed ferromagnet UNiSi2

    SciTech Connect

    Sakai, Hironori; Baek, Seung H; Bauer, Eric D; Ronning, Filip; Thompson, J D

    2009-01-01

    UNiSi{sub 2} orders ferromagnetically below T{sub Curie} = 95 K. This material crystallizes in the orthorhombic CeNiSi{sub 2}-type structure. The uranium atoms form double-layers, which are stacked along the crystallographic b axis (the longest axis). From magnetization measurement the easy (hard) magnetization axis is found to be the c axis (b axis). {sup 29}Si-NMR measurements have been performed in the paramagnetic state. In UNiSi{sub 2}, two crystallographic Si sites exist with orthorhombic local symmetry. The Knight shifts on each Si site have been estimated from the spectra of random and oriented powders. The transferred hyperfine couplings have been also derived. It is found that the transferred hyperfine coupling constants on each Si site are nearly isotropic, and that their Knight shift anisotropy comes from that of the bulk susceptibility. The nuclear-spin lattice relaxation rate 1/T{sub 1} shows temperature-independent behavior, which indicates the existence of localized 5f electron.

  15. Effect of vanadium neighbors on the hyperfine properties of iron vanadium alloys

    NASA Astrophysics Data System (ADS)

    Elzain, M.; Yousif, A.; Gismelseed, A.; Al Rawas, A.; Widatallah, H.; Bouziane, K.; Al-Omari, I.

    2008-06-01

    The electronic and magnetic structures of Fe V alloys are calculated using the discrete-variational and full-potential linearized-augmented-plane wave methods. The derived hyperfine properties at Fe sites are studied against the number of Fe atoms in the neighbouring shells. As expected the magnetic hyperfine field depends strongly on the number of Fe atoms in the first and second shells of neighbours while its dependence on the variation of atoms in the third shell is weak. The calculated distribution of the magnetic hyperfine fields at the Fe sites, are compared to the experimental data of Krause et al. (Phys Rev B 61:6196 6204, 2000). The contact charge densities and the magnetic moments are also calculated. It was found that the contact charge density increases with increasing V contents and this leads to negative isomer shift on addition of V.

  16. Buffer-gas-induced shift and broadening of hyperfine resonances in alkali-metal vapors

    NASA Astrophysics Data System (ADS)

    Oreto, P. J.; Jau, Y.-Y.; Post, A. B.; Kuzma, N. N.; Happer, W.

    2004-04-01

    We review the shift and broadening of hyperfine resonance lines of alkali-metal atoms in buffer gases. We present a simple theory both for the shift and the broadening induced by He gas. The theory is parametrized by the scattering length of slow electrons on He atoms and by the measured hyperfine intervals and binding energies of the S states of alkali-metal atoms. The calculated shifts and their temperature dependence are in good agreement with the published experimental data. The calculated broadening is 1.6 times smaller than the recent measurements, and more than 20 times smaller than the earlier measurements. We attribute much of the linewidth in the earlier experiments to possible small temperature gradients and the resulting inhomogeneous line broadening from the temperature dependence of hyperfine frequency shift at constant buffer-gas pressure.

  17. Hyperfine-structure studies of Nb ii: Experimental and relativistic configuration-interaction results

    NASA Astrophysics Data System (ADS)

    Young, L.; Hasegawa, S.; Kurtz, C.; Datta, Debasis; Beck, Donald R.

    1995-05-01

    We report an experimental and theoretical study of the hyperfine structure (hfs) in various metastable states in 93Nb ii. Hyperfine structures of five levels in Nb ii have been measured using a combination of the laser-rf double resonance and laser-induced fluorescence methods in a collinear laser-ion-beam geometry. Theoretically, for J=2, a multireference calculation of energies and hfs based on a relativistic configuration-interaction methodology of the lowest ten levels in the (4d+5s)4 manifold is reported. The average energy error is 450 cm-1. Many of the hyperfine constants show large changes from the Dirac-Fock values and the magnetic dipole constant has a 4% accuracy for the one J=2 level measured. We have also identified all the core-valence and core-core effects that dominate the energy differences and hfs.

  18. Absolute frequency measurements and hyperfine structures of the molecular iodine transitions at 578 nm

    NASA Astrophysics Data System (ADS)

    Kobayashi, Takumi; Akamatsu, Daisuke; Hosaka, Kazumoto; Inaba, Hajime; Okubo, Sho; Tanabe, Takehiko; Yasuda, Masami; Onae, Atsushi; Hong, Feng-Lei

    2016-04-01

    We report absolute frequency measurements of 81 hyperfine components of the rovibrational transitions of molecular iodine at 578 nm using the second harmonic generation of an 1156-nm external-cavity diode laser and a fiber-based optical frequency comb. The relative uncertainties of the measured absolute frequencies are typically $1.4\\times10^{-11}$. Accurate hyperfine constants of four rovibrational transitions are obtained by fitting the measured hyperfine splittings to a four-term effective Hamiltonian including the electric quadrupole, spin-rotation, tensor spin-spin, and scalar spin-spin interactions. The observed transitions can be good frequency references at 578 nm, and are especially useful for research using atomic ytterbium since the transitions are close to the $^{1}S_{0}-^{3}P_{0}$ clock transition of ytterbium.

  19. Calculation of radiative corrections to hyperfine splittings in the neutral alkali metals

    SciTech Connect

    Sapirstein, J.; Cheng, K.T.

    2003-02-01

    The radiative correction to hyperfine splitting in hydrogen is dominated by the Schwinger term, {alpha}/2{pi} E{sub F}, where E{sub F} is the lowest-order hyperfine splitting. Binding corrections to this term, which enter as powers and logarithms of Z{alpha}, can be expected to be increasingly important in atoms with higher nuclear charge Z. Methods that include all orders of Z{alpha}, developed first to study highly charged ions, are adapted to the study of the neutral alkali metals, lithium through francium. It is shown that the use of the Schwinger term alone to account for radiative corrections to hyperfine splittings becomes qualitatively incorrect for the heavier alkali metals.0.

  20. Direct observation of the hyperfine transition of ground-state positronium.

    PubMed

    Yamazaki, T; Miyazaki, A; Suehara, T; Namba, T; Asai, S; Kobayashi, T; Saito, H; Ogawa, I; Idehara, T; Sabchevski, S

    2012-06-22

    We report the first direct measurement of the hyperfine transition of the ground state positronium. The hyperfine structure between ortho-positronium and para-positronium is about 203 GHz. We develop a new optical system to accumulate about 10 kW power using a gyrotron, a mode converter, and a Fabry-Pérot cavity. The hyperfine transition has been observed with a significance of 5.4 standard deviations. The transition probability is measured to be A = 3.1(-1.2)(+1.6) × 10(-8) s(-1) for the first time, which is in good agreement with the theoretical value of 3.37 × 10(-8) s(-1). PMID:23004598

  1. Experimental verification of isotope shift and hyperfine structure of some even parity levels of neutral Eu

    NASA Astrophysics Data System (ADS)

    Furmann, B.; Stefanska, D.

    2014-09-01

    The results of measurements of the hyperfine structure of 31 classified and four unclassified spectral lines in the europium atom, obtained by using the laser induced fluorescence method, are presented. On the basis of experimental results, the values of the hyperfine structure constants and the isotope shifts for seven hitherto unmeasured levels belonging to even configurations (among them for three entirely new levels with unknown energies) were determined and the respective values known from literature for another 19 levels were verified. Since the motivation for undertaking investigations within this work was an inconsistency in the semi-empirical description of the hyperfine structure and the isotope shifts for some even levels in the europium atom, a detailed discussion of this problem is presented.

  2. Hyperfine-resolved 3.4-{mu}m spectroscopy of CH{sub 3}I with a widely tunable difference frequency generation source and a cavity-enhanced cell: A case study of a local Coriolis interaction between the v{sub 1}=1 and (v{sub 2},v{sub 6}{sup l})=(1,2{sup 2}) states

    SciTech Connect

    Okubo, Sho; Nakayama, Hirotaka; Sasada, Hiroyuki

    2011-01-15

    Saturated absorption spectra of the {nu}{sub 1} fundamental band of CH{sub 3}I are recorded with a cavity-enhanced cell and a tunable difference frequency generation source having an 86-cm{sup -1} range. The recorded spectral lines are 250 kHz wide, and most of them are resolved into the individual hyperfine components. The Coriolis interaction between the v{sub 1}=1 and (v{sub 2},v{sub 6}{sup l})=(1,2{sup 2}) states locally perturbing the hyperfine structures is analyzed to yield the Coriolis and hyperfine coupling constants with uncertainties similar to those in typical microwave spectroscopy. The spectrometer has demonstrated the potential for precisely determining the energy structure in the vibrational excited states.

  3. Absence of the hyperfine magnetic field at the Ru site in ferromagnetic rare-earth intermetallics

    SciTech Connect

    Coffey, D.; DeMarco, M.; Ho, P. C.; Maple, M. B.; Sayles, T.; Lynn, J. W.; Huang, Q.; Toorongian, S.; Haka, M.

    2010-05-01

    The Moessbauer effect (ME) is frequently used to investigate magnetically ordered systems. One usually assumes that the magnetic order induces a hyperfine magnetic field, B{sub hyperfine}, at the ME active site. This is the case in the ruthenates, where the temperature dependence of B{sub hyperfine} at {sup 99}Ru sites tracks the temperature dependence of the ferromagnetic or antiferromagnetic order. However this does not happen in the rare-earth intermetallics, GdRu{sub 2} and HoRu{sub 2}. Specific heat, magnetization, magnetic susceptibility, Moessbauer effect, and neutron diffraction have been used to study the nature of the magnetic order in these materials. Both materials are found to order ferromagnetically at 83.1 and 15.3 K, respectively. Despite the ferromagnetic order of the rare-earth moments in both systems, there is no evidence of a correspondingly large B{sub hyperfine} in the Moessbauer spectrum at the Ru site. Instead the measured spectra consist of a narrow peak at all temperatures which points to the absence of magnetic order. To understand the surprising absence of a transferred hyperfine magnetic field, we carried out ab initio calculations which show that spin polarization is present only on the rare-earth site. The electron spin at the Ru sites is effectively unpolarized and, as a result, B{sub hyperfine} is very small at those sites. This occurs because the 4d Ru electrons form broad conduction bands rather than localized moments. These 4d conduction bands are polarized in the region of the Fermi energy and mediate the interaction between the localized rare-earth moments.

  4. Hyperfine structure constants for singly ionized manganese (Mn II) using Fourier transform spectroscopy

    NASA Astrophysics Data System (ADS)

    Townley-Smith, Keeley; Nave, Gillian; Pickering, Juliet C.; Blackwell-Whitehead, Richard J.

    2016-09-01

    We expand on the comprehensive study of hyperfine structure (HFS) in Mn II conducted by Holt et al. (1999) by verifying hyperfine magnetic dipole constants (A) for 20 levels previously measured by Holt et al. (1999) and deriving A constants for 47 previously unstudied levels. The HFS patterns were measured in archival spectra from Fourier transform (FT) spectrometers at Imperial College London and the National Institute of Standards and Technology. Analysis of the FT spectra was carried out in XGREMLIN. Our A constant for the ground level has a lower uncertainty by a factor of 6 than that of Blackwell-Whitehead et al.

  5. Hyperfine structure of the ground state in muonic-lithium ions

    NASA Astrophysics Data System (ADS)

    Martynenko, A. P.; Ulybin, A. A.

    2016-03-01

    Small intervals of the hyperfine structure of the ground state in the muonic-lithium ions ( μe 3 6,7 Li)+ were calculated by perturbation theory in the fine-structure constant and in the electronto- muon mass ratio. Vacuum-polarization, recoil, and nuclear-structure effects and electron vertex corrections were taken into account. The values obtained for the small hyperfine-splitting intervals can be used in a comparison with future experimental data and in tests of quantum electrodynamics.

  6. Effects of Hyperfine Mixing of Rydberg-ground molecular potentials in Rb

    NASA Astrophysics Data System (ADS)

    Maclennan, Jamie; Ramos, Andira; Thaicharoen, Nithiwadee; Raithel, Georg

    2016-05-01

    Rydberg molecules formed by the scattering between a ground-state atom and a Rydberg electron can offer new insight into the nature of atomic interactions and molecular structure. Shallow bound states that arise from hyperfine-induced mixing of singlet and triplet channels have recently been predicted and observed for P-states in Cs and S-states in 87 Rb. Here we present progress toward characterizing Rb (nD + 5 S1/2) molecules, including a comparison of the hyperfine-mixing effects between the two isotopes (85 Rb and 87 Rb).

  7. Hyperfine field of einsteinium in iron and nuclear magnetic moment of {sup 254}Es

    SciTech Connect

    Severijns, N.; Kraev, I. S.; Phalet, T.; Tandecki, M.; Traykov, E.; Gorp, S. Van; Wauters, F.; Belyaev, A. A.; Lukhanin, A. A.; Noga, V. I.; Erzinkyan, A. L.; Parfenova, V. P.; Eversheim, P.-D.; Herzog, P.; Tramm, C.; Filimonov, V. T.; Toporov, Yu. G.; Zotov, E.; Golovko, V. V.; Gurevich, G. M.

    2009-06-15

    The angular distributions of {gamma} rays and {alpha} particles from oriented {sup 250}Bk, {sup 253,254}Es, and {sup 255}Fm nuclei were investigated to extract hyperfine interaction information for these actinide impurities in an iron host lattice. The hyperfine field of einsteinium in iron was found to be |B{sub hf}(EsFe{sub lowbar|})=396(32) T. With this value the magnetic moment of {sup 254}Es was then determined as |{mu}|=4.35(41) {mu}{sub N}.

  8. Suppression of ultracold ground-state hyperfine-changing collisions with laser light

    SciTech Connect

    Sanchez-Villicana, V.; Gensemer, S.D.; Tan, K.Y.N.; Kumarakrishnan, A.; Dinneen, T.P.; Sueptitz, W.; Gould, P.L.

    1995-06-05

    Using laser light tuned to a repulsive molecular potential, we have been able to suppress inelastic ground-state hyperfine-changing collisions between ultracold {sup 87}Rb atoms. Adiabatic excitation to the repulsive curve alters the atomic trajectories and prevents the atoms from approaching close enough for the hyperfine change to occur. Experimental results show suppressions up to {similar_to}50% and are in reasonable agreement with a simple Landau-Zener model. Our ability to control collisional trap loss processes may have important implications for the achievement of high densities in laser cooled samples.

  9. Precision Measurements of Atomic Lifetimes and Hyperfine Energies in Alkali Like Systems

    SciTech Connect

    Tanner, Carol E.

    2005-03-04

    Financial support of this research project has lead to advances in the study of atomic structure through precision measurements of atomic lifetimes, energy splittings, and transitions energies. The interpretation of data from many areas of physics and chemistry requires an accurate understanding of atomic structure. For example, scientists in the fields of astrophysics, geophysics, and plasma fusion depend on transition strengths to determine the relative abundances of elements. Assessing the operation of discharges and atomic resonance line filters also depends on accurate knowledge of transition strengths. Often relative transition strengths are measured precisely, but accurate atomic lifetimes are needed to obtain absolute values. Precision measurements of atomic lifetimes and energy splittings also provide fundamentally important atomic structure information. Lifetimes of allowed transitions depend most strongly on the electronic wave function far from the nucleus. Alternatively, hyperfine splittings give important information about the electronic wave function in the vicinity of the nucleus as well as the structure of the nucleus. Our main focus throughout this project has been the structure of atomic cesium because of its connection to the study of atomic parity nonconservation (PNC). The interpretation of atomic PNC experiments in terms of weak interaction coupling constants requires accurate knowledge of the electronic wave function near the nucleus as well as far from the nucleus. It is possible to address some of these needs theoretically with sophisticated many-electron atomic structure calculations. However, this program has been able to address these needs experimentally with a precision that surpasses current theoretical accuracy. Our measurements also play the important role of providing a means for testing the accuracy of many-electron calculations and guiding further theoretical development, Atomic systems such as cesium, with a single electron

  10. Hyperfine magnetic field on Cd-111 in Heusler alloys Co2MnZ (Z = Si, Ga, Ge, Sn)

    NASA Technical Reports Server (NTRS)

    Jha, S.; Mitros, C.; Lahamer, Amer; Yehia, Sherif; Julian, Glenn M.

    1989-01-01

    The time differential perturbed angular correlation method has been used to measure, as a function of temperature, the hyperfine magnetic field at Cd sites in the Heusler alloys Co2MnZ (Z = Si, Ga, Ge, Sn). The hyperfine fields, normalized to the total magnetic moment per formula unit, show an approximately linear trend toward more positive values with increasing lattice parameter.

  11. Hypernuclei in the quark-meson coupling model

    SciTech Connect

    K. Tsushima, P. A. M. Guichon

    2010-07-01

    We present results of hypernuclei calculated in the latest quark-meson coupling (QMC) model, where the effect of the mean scalar field in-medium on the one-gluon exchange hyperfine interaction, is also included self-consistently. The extra repulsion associated with this increased hyperfine interaction in-medium completely changes the predictions for {\\Sigma} hypernuclei. Whereas in the earlier version of QMC they were bound by an amount similar to {\\Lambda} hypernuclei, they are unbound in the latest version of QMC, in qualitative agreement with the experimental absence of such states.

  12. High-Frequency/High-field electron spin echo envelope modulation study of nitrogen hyperfine and quadrupole interactions on a disordered powder sample

    PubMed

    Bloess; Mobius; Prisner

    1998-09-01

    High-frequency/high-field (95 GHz/3.4 T) electron spin echo envelope modulation (ESEEM) experiments on single crystals and disordered samples of dianisyl-nitroxide (DANO) radicals are reported. At these high microwave frequencies (W-band), the anisotropic g-matrix of the nitroxide radical is resolved in the EPR spectrum. Additionally ESEEM modulations from other than nitrogen nuclei, such as protons, are highly suppressed at these frequencies, because they are too far from the cancellation condition for effective mixing of the nuclear spin functions. Therefore the nitrogen (14N) hyperfine and quadrupole coupling tensors could be determined without ambiguity from powder measurements. The results obtained were checked by ESEEM measurements on single crystals. Advantages and disadvantages of high-field ESEEM on nitrogen couplings are briefly discussed and compared with electron nuclear double resonance (ENDOR) and X-band ESEEM. Copyright 1998 Academic Press. PMID:9740727

  13. Symmetry-suppressed two-photon transitions induced by hyperfine interactions and magnetic fields

    SciTech Connect

    Kozlov, M. G.; English, D.; Budker, D.

    2009-10-15

    Two-photon transitions between atomic states of total electronic angular-momentum J{sub a}=0 and J{sub b}=1 are forbidden when the photons are of the same energy. This selection rule is analogous to the Landau-Yang theorem in particle physics that forbids decays of vector particle into two photons. It arises because it is impossible to construct a total angular-momentum J{sub 2{gamma}}=1 quantum-mechanical state of two photons that is permutation symmetric, as required by Bose-Einstein statistics. In atoms with nonzero nuclear spin, the selection rule can be violated due to hyperfine interactions. Two distinct mechanisms responsible for the hyperfine-induced two-photon transitions are identified, and the hyperfine structure of the induced transitions is evaluated. The selection rule is also relaxed, even for zero-nuclear-spin atoms, by application of an external magnetic field. Once again, there are two similar mechanisms at play: Zeeman splitting of the intermediate-state sublevels, and off-diagonal mixing of states with different total electronic angular momentum in the final state. The present theoretical treatment is relevant to the ongoing experimental search for a possible Bose-Einstein-statistics violation using two-photon transitions in barium, where the hyperfine-induced transitions have been recently observed, and the magnetic-field-induced transitions are being considered both as a possible systematic effect, and as a way to calibrate the measurement.

  14. Narrow 87Rb and 133Cs hyperfine transitions in evacuated wall-coated cells

    NASA Technical Reports Server (NTRS)

    Robinson, H. G.; Johnson, C. E.

    1983-01-01

    An extension of work on wall-coated cells was made to include observation by a triple resonance technique of the 0-0 hyperfine transitions in 87Rb and 133Cs. Conventional RF excited lamps were used. Interest in such cells is for possible application in atomic clocks. The Rb cell would appear to remain especially promising in this respect.

  15. Investigations of hyperfine and isotope structures in optical spectra of crystals with rare-earth ions

    NASA Astrophysics Data System (ADS)

    Popova, M. N.

    2015-10-01

    This is a review of works on hyperfine and isotope structures in the spectra of rare-earth ions in crystals that have been performed at the Laboratory of Fourier Spectroscopy of the Institute for Spectroscopy, Russian Academy of Sciences. The applicability of these studies to the development of optical quantum memory is discussed.

  16. Towards measuring the ground state hyperfine splitting of antihydrogen - a progress report

    NASA Astrophysics Data System (ADS)

    Sauerzopf, C.; Capon, A. A.; Diermaier, M.; Dupré, P.; Higashi, Y.; Kaga, C.; Kolbinger, B.; Leali, M.; Lehner, S.; Rizzini, E. Lodi; Malbrunot, C.; Mascagna, V.; Massiczek, O.; Murtagh, D. J.; Nagata, Y.; Radics, B.; Simon, M. C.; Suzuki, K.; Tajima, M.; Ulmer, S.; Vamosi, S.; Gorp, S. van; Zmeskal, J.; Breuker, H.; Higaki, H.; Kanai, Y.; Kuroda, N.; Matsuda, Y.; Venturelli, L.; Widmann, E.; Yamazaki, Y.

    2016-12-01

    We report the successful commissioning and testing of a dedicated field-ioniser chamber for measuring principal quantum number distributions in antihydrogen as part of the ASACUSA hyperfine spectroscopy apparatus. The new chamber is combined with a beam normalisation detector that consists of plastic scintillators and a retractable passivated implanted planar silicon (PIPS) detector.

  17. Hyperfine Quenching of the 2s2p 3P0 State of Berylliumlike Ions

    SciTech Connect

    Cheng, K T; Chen, M H; Johnson, W R

    2008-03-13

    The hyperfine-induced 2s2p {sup 3}P{sub 0}-2s{sup 2} {sup 1}S{sub 0} transition rate for Be-like {sup 47}Ti{sup 18+} was recently measured in a storage-ring experiment by Schippers et al. [Phys. Rev. Lett. 98, 033001 (2007)]. The measured value of 0.56(3) s{sup -1} is almost 60% larger than the theoretical value of 0.356 s{sup -1} from a multiconfiguration Dirac-Fock calculation by Marques et al. [Phys. Rev. A 47, 929 (1993)]. In this work, we use a large-scale relativistic configuration-interaction method to calculate these hyperfine-induced rates for ions with Z = 6-92. Coherent hyperfine-quenching effects between the 2s2p {sup 1,3}P{sub 1} states are included in a perturbative as well as a radiation damping approach. Contrary to the claims of Marques et al., contributions from the {sup 1}P{sub 1} state are substantial and lead to a hyperfine-induced rate of 0.67 s{sup -1}, in better agreement with, though larger than, the measured value.

  18. First-principles study of boron oxygen hole centers in crystals: Electronic structures and nuclear hyperfine and quadrupole parameters

    SciTech Connect

    Li Zucheng; Pan Yuanming

    2011-09-15

    The electronic structures, nuclear hyperfine coupling constants, and nuclear quadrupole parameters of fundamental boron oxygen hole centers (BOHCs) in zircon (ZrSiO{sub 4}, I4{sub 1}/amd) and calcite (CaCO{sub 3}, R3c) have been investigated using ab initio Hartree-Fock (HF) and various density functional theory (DFT) methods based on the supercell models with all-electron localized basis sets. Both exact HF exchange and appropriate correlation functionals are important in describing the BOHCs, and the parameter-free hybrid method based on Perdew, Burke, and Ernzerhof density functionals (PBE0) turns out to be the best DFT method in reproducing the electron paramagnetic resonance (EPR) data. Our results reveal three distinct types of simple-spin (S = 1/2) [BO{sub 3}]{sup 2-} centers in calcite: (i) the classic [BO{sub 3}]{sup 2-} radical with the D{sub 3h} symmetry and the unpaired spin equally distributed on the three oxygen atoms (i.e. the O{sub 3}{sup 5-} type); (ii) the previously reported [BO{sub 2}]{sup 0} center with the unpaired spin equally distributed on two of the three oxygen atoms (O{sub 2}{sup 3-}); and (iii) a new variety with {approx}90% of its unpaired spin localized on one (O{sup -}) of the three oxygen atoms with a long B-O bond (1.44 A). Calculations confirm the unusual [BO{sub 4}]{sup 0} center in zircon and show it to arise from a highly distorted configuration with 90% of the unpaired spin on one oxygen atom that has a considerably longer B-O bond (1.68 A) than its three counterparts (1.45 A). The calculated magnitudes and directions of {sup 11}B and {sup 17}O hyperfine coupling constants and nuclear quadrupole constants for the [BO{sub 4}]{sup 0} center in zircon are in excellent agreement with the 15 K EPR experimental data. These BOHCs are all characterized by a small negative spin density on the central B atom arising from spin polarization. Our calculations also demonstrate that the spin densities on BOHCs are affected substantially by

  19. Hyperfine rather than spin splittings dominate the fine structure of the B 4Σ--X 4Σ- bands of AlC

    NASA Astrophysics Data System (ADS)

    Clouthier, Dennis J.; Kalume, Aimable

    2016-01-01

    Laser-induced fluorescence and wavelength resolved emission spectra of the B 4Σ--X 4Σ- band system of the gas phase cold aluminum carbide free radical have been obtained using the pulsed discharge jet technique. The radical was produced by electron bombardment of a precursor mixture of trimethylaluminum in high pressure argon. High resolution spectra show that each rotational line of the 0-0 and 1-1 bands of AlC is split into at least three components, with very similar splittings and intensities in both the P- and R-branches. The observed structure was reproduced by assuming bβS magnetic hyperfine coupling in the excited state, due to a substantial Fermi contact interaction of the unpaired electron in the aluminum 3s orbital. Rotational analysis has yielded ground and excited state equilibrium bond lengths in good agreement with the literature and our own ab initio values. Small discrepancies in the calculated intensities of the hyperfine lines suggest that the upper state spin-spin constant λ' is of the order of ≈0.025-0.030 cm-1.

  20. Hyperfine-induced spin relaxation of a hopping carrier: implications for spin transport in 1-D vs 3-D organic semiconductors

    NASA Astrophysics Data System (ADS)

    Mkhitaryan, Vagharsh; Dobrovitski, Viatcheslav; 0 Team

    2015-03-01

    The hyperfine coupling of a carrier spin to a nuclear spin bath is a predominant channel for the carrier spin relaxation in organic semiconductors. We investigate the hyperfine-induced spin relaxation of a carrier performing a random walk on a d-dimensional regular lattice theoretically, in a transport regime typical for organic semiconductors. We show that in d = 1 and d = 2 the time dependence of spin polarization, P (t) , is dominated by a superexponential decay, crossing over to an exponential tail at long times. The faster decay is attributed to multiple self-intersections (returns) of the random walk trajectories, which occur more often in lower dimensions. We also show, analytically and numerically, that the returns lead to sensitivity of P (t) to external electric and magnetic fields, and this sensitivity strongly depends on dimensionality of the system (d = 1 vs. d = 3). Furthermore, we consider the coordinate dependence of spin polarization, σ (r) , in a hypothetic lateral or vertical organic spin-valve device. We demonstrate that, while σ (r) is essentially exponential, the effect of multiple self-intersections can be identified in transport measurements from the specific field-dependence of spin relaxation length. This work was supported by the Department of Energy-Basic Energy Sciences under Contract No. DE-AC02-07CH11358.

  1. Sub-Doppler two-photon-excitation Rydberg spectroscopy of atomic xenon: mass-selective studies of isotopic and hyperfine structure

    NASA Astrophysics Data System (ADS)

    Kono, Mitsuhiko; He, Yabai; Baldwin, Kenneth G. H.; Orr, Brian J.

    2016-03-01

    Mass-selective sub-Doppler two-photon excitation (TPE) spectroscopy is employed to resolve isotopic contributions for transitions to high-energy Rydberg levels of xenon in an atomic beam, using narrowband pulses of coherent ultraviolet light at 205-213 nm generated by nonlinear-optical conversion processes. Previous research (Kono et al 2013 J. Phys. B: At. Mol. Opt. Phys. 46 35401), has determined isotope energy shifts and hyperfine structure for 33 high-energy Rydberg levels of gas-phase xenon and accessed Rydberg levels at TPE energies in the range of 94 100-97 300 cm-1 with unprecedented spectroscopic resolution. The new isotopic-mass-resolved results were obtained by adding a pulsed free-jet atomic-beam source and a mass-selective time-of-flight detector to the apparatus in order to discern individual xenon isotopes and extract previously unresolved spectroscopic information. Resulting isotope energy shifts and hyperfine-coupling parameters are examined with regard to trends in principal quantum number n and in atomic angular-momentum quantum numbers, together with empirical and theoretical precedents for such trends.

  2. Raman-dressed spin-1 spin-orbit-coupled quantum gas

    NASA Astrophysics Data System (ADS)

    Lan, Zhihao; Öhberg, Patrik

    2014-02-01

    The recently realized spin-orbit-coupled quantum gases [Lin et al., Nature (London) 471, 83 (2011), 10.1038/nature09887; Wang et al., Phys. Rev. Lett. 109, 095301 (2012), 10.1103/PhysRevLett.109.095301; Cheuk et al., Phys. Rev. Lett. 109, 095302 (2012), 10.1103/PhysRevLett.109.095302] mark a breakthrough in the cold atom community. In these experiments, two hyperfine states are selected from a hyperfine manifold to mimic a pseudospin-1/2 spin-orbit-coupled system by the method of Raman dressing, which is applicable to both bosonic and fermionic gases. In this paper, we show that the method used in these experiments can be generalized to create any large pseudospin spin-orbit-coupled gas if more hyperfine states are coupled equally by the Raman lasers. As an example, we study, in detail, a quantum gas with three hyperfine states coupled by the Raman lasers and show, when the state-dependent energy shifts of the three states are comparable, triple-degenerate minima will appear at the bottom of the band dispersions, thus, realizing a spin-1 spin-orbit-coupled quantum gas. A novel feature of this three-minima regime is that there can be two different kinds of stripe phases with different wavelengths, which has an interesting connection to the ferromagnetic and polar phases of spin-1 spinor Bose-Einstein condensates without spin-orbit coupling.

  3. Molecular hyperfine parameters in the 1 3Σ{u/+} and 1 3Σ{g/+} states of Li2, Na2, K2 and Rb2

    NASA Astrophysics Data System (ADS)

    Lysebo, Marius; Veseth, Leif

    2013-07-01

    Magnetic hyperfine parameters have been computed for the 1 3 Σ {/u +} and 1 3 Σ {/g +} states of Li2 ,Na2 ,K2 and Rb2. The parameters were computed with MCSCF wavefunctions and the calculations were repeated for a series of internuclear distances. The results are compared with a recent observation of the hyperfine structure in Rb2, and to the atomic hyperfine parameters. The available empirical data are reproduced with high accuracy. For the present systems, the molecular hyperfine parameters are largely determined by the corresponding atomic hyperfine interactions. The computed molecular parameters at the dissociation limit deviate at most 11% from the experimentally determined atomic ones.

  4. A simplified method for calculating the ac Stark shift of hyperfine levels of alkali-metal atoms

    NASA Astrophysics Data System (ADS)

    Xu, Xia; Qing, Bo; Chen, Xuzong; Zhou, Xiaoji

    2015-07-01

    The ac Stark shift of hyperfine levels of neutral atoms can be calculated using the third order perturbation theory (TOPT), where the third order corrections are quadratic in the atom-photon interaction and linear in the hyperfine interaction. In this paper, we use Green's function to derive the E [ 2 + ɛ ] method which can give close values to those of TOPT for the differential light shift between two hyperfine levels. It comes with a simple form and easy incorporation of theoretical and experimental atomic structure data. Furthermore, we analyze the order of approximation and give the condition under which E [ 2 + ɛ ] method is valid.

  5. Hyperfine structures of the 2 3 Π(Ω = 1), 2 1 Π(Ω = 1), and 3 3Σ+(Ω = 1) states of ultracold 85 Rb133 Cs via short range photoassociation

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Tae; Shimasaki, Toshihiko; Demille, David

    2016-05-01

    We have observed new short-range photoassociation (PA) to the 2 3 Π(Ω = 1), 2 1 Π(Ω = 1), and 3 3Σ+(Ω = 1) states of ultracold 85 Rb133 Cs molecule, starting with 85 Rb and 133 Cs atoms trapped in their | FRb = 2> and | FCs = 3> hyperfine states in dark SPOT MOTs We have completed vibrational and electronic assignments of those PA states in the perturbed region where assignments were difficult due to strong mixing between electronic states through spin-orbit interaction Further, high-resolution (~10 MHz) PA spectroscopy has revealed rich hyperfine structures in the low J, which we can understand using various coupling schemes (Hund's case bβS or Hund's case bβJ) mainly considering Fermi contact interaction. Similarly, we have also observed PA lines in the strongly perturbed singlet (1 1 Π) and triplet (2 3Σ+) states, which also show similar hyperfine structures. Further, we have observed production of RbCs molecules in the rovibronic ground state through these PA lines via one-photon decay, which opens up the possibility of using these new PA lines as an efficient direct path to the rovibronic ground state.

  6. Polarized scattering with Paschen-Back effect, hyperfine structure, and partial frequency redistribution in magnetized stellar atmospheres

    SciTech Connect

    Sowmya, K.; Nagendra, K. N.; Sampoorna, M.; Stenflo, J. O. E-mail: knn@iiap.res.in E-mail: stenflo@astro.phys.ethz.ch

    2014-05-10

    F-state interference significantly modifies the polarization produced by scattering processes in the solar atmosphere. Its signature in the emergent Stokes spectrum in the absence of magnetic fields is depolarization in the line core. In the present paper, we derive the partial frequency redistribution (PRD) matrix that includes interference between the upper hyperfine structure states of a two-level atom in the presence of magnetic fields of arbitrary strengths. The theory is applied to the Na I D{sub 2} line that is produced by the transition between the lower J = 1/2 and upper J = 3/2 states which split into F states because of the coupling with the nuclear spin I{sub s} = 3/2. The properties of the PRD matrix for the single-scattering case is explored, in particular, the effects of the magnetic field in the Paschen-Back regime and their usefulness as a tool for the diagnostics of solar magnetic fields.

  7. Torsionally mediated spin-rotation hyperfine splittings at moderate to high J values in methanol.

    PubMed

    Belov, S P; Golubiatnikov, G Yu; Lapinov, A V; Ilyushin, V V; Alekseev, E A; Mescheryakov, A A; Hougen, J T; Xu, Li-Hong

    2016-07-14

    This paper presents an explanation based on torsionally mediated proton-spin-overall-rotation interaction for the observation of doublet hyperfine splittings in some Lamb-dip sub-millimeter-wave transitions between ground-state torsion-rotation states of E symmetry in methanol. These unexpected doublet splittings, some as large as 70 kHz, were observed for rotational quantum numbers in the range of J = 13 to 34, and K = - 2 to +3. Because they increase nearly linearly with J for a given branch, we confined our search for an explanation to hyperfine operators containing one nuclear-spin angular momentum factor I and one overall-rotation angular momentum factor J (i.e., to spin-rotation operators) and ignored both spin-spin and spin-torsion operators, since they contain no rotational angular momentum operator. Furthermore, since traditional spin-rotation operators did not seem capable of explaining the observed splittings, we constructed totally symmetric "torsionally mediated spin-rotation operators" by multiplying the E-species spin-rotation operator by an E-species torsional-coordinate factor of the form e(±niα). The resulting operator is capable of connecting the two components of a degenerate torsion-rotation E state. This has the effect of turning the hyperfine splitting pattern upside down for some nuclear-spin states, which leads to bottom-to-top and top-to-bottom hyperfine selection rules for some transitions, and thus to an explanation for the unexpectedly large observed hyperfine splittings. The constructed operator cannot contribute to hyperfine splittings in the A-species manifold because its matrix elements within the set of torsion-rotation A1 and A2 states are all zero. The theory developed here fits the observed large doublet splittings to a root-mean-square residual of less than 1 kHz and predicts unresolvable splittings for a number of transitions in which no doublet splitting was detected. PMID:27421405

  8. Torsionally mediated spin-rotation hyperfine splittings at moderate to high J values in methanol

    NASA Astrophysics Data System (ADS)

    Belov, S. P.; Golubiatnikov, G. Yu.; Lapinov, A. V.; Ilyushin, V. V.; Alekseev, E. A.; Mescheryakov, A. A.; Hougen, J. T.; Xu, Li-Hong

    2016-07-01

    This paper presents an explanation based on torsionally mediated proton-spin-overall-rotation interaction for the observation of doublet hyperfine splittings in some Lamb-dip sub-millimeter-wave transitions between ground-state torsion-rotation states of E symmetry in methanol. These unexpected doublet splittings, some as large as 70 kHz, were observed for rotational quantum numbers in the range of J = 13 to 34, and K = - 2 to +3. Because they increase nearly linearly with J for a given branch, we confined our search for an explanation to hyperfine operators containing one nuclear-spin angular momentum factor I and one overall-rotation angular momentum factor J (i.e., to spin-rotation operators) and ignored both spin-spin and spin-torsion operators, since they contain no rotational angular momentum operator. Furthermore, since traditional spin-rotation operators did not seem capable of explaining the observed splittings, we constructed totally symmetric "torsionally mediated spin-rotation operators" by multiplying the E-species spin-rotation operator by an E-species torsional-coordinate factor of the form e±niα. The resulting operator is capable of connecting the two components of a degenerate torsion-rotation E state. This has the effect of turning the hyperfine splitting pattern upside down for some nuclear-spin states, which leads to bottom-to-top and top-to-bottom hyperfine selection rules for some transitions, and thus to an explanation for the unexpectedly large observed hyperfine splittings. The constructed operator cannot contribute to hyperfine splittings in the A-species manifold because its matrix elements within the set of torsion-rotation A1 and A2 states are all zero. The theory developed here fits the observed large doublet splittings to a root-mean-square residual of less than 1 kHz and predicts unresolvable splittings for a number of transitions in which no doublet splitting was detected.

  9. Influence of the anisotropic hyperfine interaction on the 14N ENDOR and the ESEEM orientation-disordered spectra.

    PubMed

    Benetis, Nikolas P; Dikanov, Sergei A

    2005-07-01

    The influence of the anisotropic hyperfine interaction on the 14N electron-nuclear double resonance/electron spin echo envelope modulation spectra is studied by approximate analytical and graphical methods for the case of the isotropic g-factor. The suggested determination of the modified characteristic directions of the magnetic field due to anisotropy enhances the insight in the structural details of the system and analytical solutions of the secular equation for these conditions are derived. The graphical method, previously used for the analysis of the orientation dependence of the 14N nuclear-transition frequencies in orientation-disordered samples for isotropic hyperfine interaction is extended to the case of arbitrary anisotropic hyperfine tensor. The above analytical and graphical methods are illustrated and tested against exact simulations in two practically important cases: (i) isotropic hyperfine interaction (hfi) exceeding other nuclear interactions in nuclear spin Hamiltonian. (ii) Cancellation of the isotropic part of the hfi. PMID:15878298

  10. Theory for Electronic Structure and Associated Hyperfine Interactions for Neutral Vacancy-Associated Hydrogen (Muonium) Atom Center in Silicon

    NASA Astrophysics Data System (ADS)

    Li, Hong; Sahoo, N.; Das, T. P.; Scheuermann, R.; Nagamine, K.

    2001-03-01

    The electronic structure and associated magnetic hyperfine interactions for the Neutral Vacancy-Associated Hydrogen (Muonium) Atom Center(B. Bech Nielsen et al., Phys. Rev. Lett. 79, 1507 (1997))^,(M.Schefzik et al, Solid State Commun. 107, 395 (1998)) in Silicon have been investigated using theHartree-Fock Cluster Procedure combined with many-body effects incorporated by perturbation methods. The influence of cluster size, size of electronic basis-set and lattice relaxation due to the presence of both the vacancy and muonium atom, have been studied. The results provide an explanation of the axial anisotropy of the hyperfine interaction tensors and the signs of the isotropic hyperfine constant and dipolar tensor components. The sizes of the calculated hyperfine tensor components are however found to be somewhat larger than experiment. Possible sources that could bridge the differences will be discussed.

  11. Hyperfine magnetic field at Ta impurities in nickel: Perturbed angular correlation and first principle calculation study

    NASA Astrophysics Data System (ADS)

    Cekić, B. Dj.; Umićević, A. B.; Belošević-Čavor, J. N.; Koteski, V. J.; Ivanovski, V. N.; Stojković, M. N.

    2008-03-01

    The hyperfine magnetic field (H) in 0.2 at.% Hf-Ni alloy is measured at the 181Ta probe using the time-differential perturbed angular correlation (TDPAC) method, in the temperature range 78-675 K. The obtained value of 8.6 (3) T at room temperature is in good agreement with the previously reported measurements for similar Hf concentrations in Ni. X-ray powder diffraction (XRPD) experiments confirmed that small atomic concentrations of Hf atoms (<1 at.%) mainly substitute on Ni lattice sites in the fcc crystal lattice without forming any intermetallic phase. In addition, ab-initio calculation using all-electron augmented plane waves plus local orbitals (APW+lo) formalism is performed and the obtained result for the hyperfine magnetic field at Ta site is in accordance with the measurement.

  12. Application of the laser ion source for isotope shift and hyperfine structure investigation

    NASA Astrophysics Data System (ADS)

    Seliverstov, M. D.; Barzakh, A. E.; Chubukov, I. Ya.; Fedorov, D. V.; Panteleev, V. N.; Volkov, Yu. M.

    2000-08-01

    The study of nuclei far from stability requires high sensitivity of the experimental technique. The method of Resonance Ionization Spectroscopy in a Laser Ion Source (RIS/LIS) allows one to carry out measurements of the isotope shifts and hyperfine splittings for isotopes at the production rate about 102 atoms per second. The sensitivity of this method is determined by the high efficiency of the laser ion source and the low background of the detection system afforded by characteristic α particle registration. The isotope shifts and hyperfine structures of 155Yb, 154Tm (I=9 and I=2) and 153Tm (I=11/2) have been measured and the isotopic changes in mean square charge radii and nuclear electromagnetic moments have been determined. The further development of this experimental method - enhanced Target Ion Source system aimed to suppress thermionic background - enables direct detection of the photoions and widens the range of the applicability of the RIS/LIS method.

  13. Theoretical Hyperfine Structure of the Molecular Hydrogen Ion at the 1 ppm Level.

    PubMed

    Korobov, Vladimir I; Koelemeij, J C J; Hilico, L; Karr, J-Ph

    2016-02-01

    We revisit the mα^{6}(m/M) order corrections to the hyperfine splitting in the H_{2}^{+} ion and find a hitherto unrecognized second-order relativistic contribution associated with the vibrational motion of the nuclei. Inclusion of this correction term produces theoretical predictions which are in excellent agreement with experimental data [K. B. Jefferts, Phys. Rev. Lett. 23, 1476 (1969)], thereby concluding a nearly 50-year-long theoretical quest to explain the experimental results within their 1-ppm error. The agreement between the theory and experiment corroborates the proton structural properties as derived from the hyperfine structure of atomic hydrogen. Our work furthermore indicates that, for future improvements, a full three-body evaluation of the mα^{6}(m/M) correction term will be mandatory. PMID:26894709

  14. Determination of hyperfine-induced transition rates from observations of a planetary nebula.

    PubMed

    Brage, Tomas; Judge, Philip G; Proffitt, Charles R

    2002-12-31

    Observations of the planetary nebula NGC3918 made with the STIS instrument on the Hubble Space Telescope reveal the first unambiguous detection of a hyperfine-induced transition 2s2p 3P(o)(0)-->2s2 1S0 in the berylliumlike emission line spectrum of N IV at 1487.89 A. A nebular model allows us to confirm a transition rate of 4x10(-4) sec(-1)+/-33% for this line. The measurement represents the first independent confirmation of the transition rate of hyperfine-induced lines in low ionization stages, and it provides support for the techniques used to compute these transitions for the determination of very low densities and isotope ratios. PMID:12513129

  15. ESR study of 2-substituted 2-adamantyl radicals. Configuration and long-range hyperfine interaction

    SciTech Connect

    Kira, Mitsuo; Akiyama, Mieko; Ichinose, Michiko; Sakurai, Hideki )

    1989-10-11

    Structure and long-range hyperfine interaction in 2-adamantyl, 5,7-dimethyl-2-adamantyl, and the various 2-substituted radicals (substituent = CH{sub 3}, CH{sub 2}SiMe{sub 3}, OSiMe{sub 3}, SSiMe{sub 3}, CH{sub 2}GeMe{sub 3}, etc.) were studied by ESR. The origin of the long-range hyperfine interaction is discussed on the basis of the comparison between experimental and theoretical hfs values. The analyses of hfs values for persistent 2-bis(trimethylsilyl)methyl-2-adamantyl radical and the 5,7-dimethyl derivative were made by the assistance of the ENDOR spectrum.

  16. Precision Hyperfine Structure of 2;^3P State of ^3He with External Magnetic

    NASA Astrophysics Data System (ADS)

    Wu, Qixue; Drake, G. W. F.

    2007-06-01

    The theory of the Zeeman effect can be used to extrapolate precise measurements for the fine structure or the hyperfine structure to zero-field strength. In the present work, the hyperfine structure of 2;^3P state of ^3He with external magnetic fields is precisely calculated. The values of the fields for 32 crossings and five anticrossings of the magnetic sublevels are theoretically predicted for magnetic field strengths up to 1 Tesla. The results are compared with experimental work. We include the linear terms, diamagnetic terms, and the 2̂ relativistic correction terms in the Zeeman Hamiltonian. All related matrix elements are calculated with high accuracy by the use of double basis set Hylleraas type variational wave functions[1,2].[1] Z. -C. Yan and G.W.F. Drake, Phys. Rev. A 50, R1980 (1994).[2] Q. Wu and G.W.F. Drake, J. Phys. B 40, 393 (2007).

  17. Theoretical Hyperfine Structure of the Molecular Hydrogen Ion at the 1 ppm Level

    NASA Astrophysics Data System (ADS)

    Korobov, Vladimir I.; Koelemeij, J. C. J.; Hilico, L.; Karr, J.-Ph.

    2016-02-01

    We revisit the m α6(m /M ) order corrections to the hyperfine splitting in the H2+ ion and find a hitherto unrecognized second-order relativistic contribution associated with the vibrational motion of the nuclei. Inclusion of this correction term produces theoretical predictions which are in excellent agreement with experimental data [K. B. Jefferts, Phys. Rev. Lett. 23, 1476 (1969)], thereby concluding a nearly 50-year-long theoretical quest to explain the experimental results within their 1-ppm error. The agreement between the theory and experiment corroborates the proton structural properties as derived from the hyperfine structure of atomic hydrogen. Our work furthermore indicates that, for future improvements, a full three-body evaluation of the m α6(m /M ) correction term will be mandatory.

  18. Hyperfine fields in Fe-Ni-X alloys and their application to a study of tempering of 9Ni steel

    SciTech Connect

    Fultz, B.; Morris, J.W. Jr.

    1984-12-01

    Hyperfine interactions due to solutes in Fe-Ni-X alloys were systematized, and interpreted with a model of linear response of hyperfine magnetic fields to magnetic moments. The effects of solutes on the /sup 57/Fe hmf were used for chemical analysis of the austenite formed in 9Ni steel during tempering. Diffusion kinetics of the Ni and X solutes were found to play an important role in the formation of the austenite particles.

  19. Study of the local magnetic environment in LaMnO3 perovskite by measuring hyperfine interactions

    NASA Astrophysics Data System (ADS)

    Junqueira, Astrogildo C.; Carbonari, Artur W.; Saxena, Rajendra N.; Mestnik-Filho, José

    2004-05-01

    TDPAC technique has been used to investigate the hyperfine interactions in the LaMnO3 perovskite using 140La(140Ce) as probe nuclei. Temperature dependence of the magnetic hyperfine field (MHF) at La sites shows an antiferromagnetic behavior with Néel temperature around 142K. For temperatures below 80K, however, the values of MHF decrease and deviate from the expected regular behavior.

  20. Hyperfine structure of excited states and quadrupole moment of Ne-21 using laser-induced line-narrowing techniques.

    NASA Technical Reports Server (NTRS)

    Ducas, T. W.; Feld, M. S.; Ryan, L. W., Jr.; Skribanowitz, N.; Javan, A.

    1972-01-01

    Observation results are presented on the optical hyperfine structure in Ne-21 obtained with the aid of laser-induced line-narrowing techniques. The output from a long stabilized single-mode 1.15-micron He-Ne laser focused into an external sample cell containing Ne-21 was used in implementing these techniques. Their applicability is demonstrated for optical hyperfine structure observation in systems whose features are ordinarily masked by Doppler broadening.

  1. Storage-ring measurements of hyperfine induced transition rates in berylliumlike ions

    SciTech Connect

    Schippers, Stefan

    2013-07-11

    The status of experimental measurements and theoretical calculations of the hyperfine induced 2s2p{sup 3}P{sub 0}{yields}2s{sup 21}S{sub 0} transition rate in Be-like ions is reviewed. Possible reasons, such as external electromagnetic fields and competing E1M1 two-photon transitions, for presently existing significant discrepancies between experiment and theory are discussed. Finally, directions for future research are outlined.

  2. Isotope shift and hyperfine splitting of the 4s→5p transition in potassium

    NASA Astrophysics Data System (ADS)

    Behrle, Alexandra; Koschorreck, Marco; Köhl, Michael

    2011-05-01

    We have investigated the 4s2S1/2→5p2P1/2 transition (D1 line) of the potassium isotopes K39, K40, and K41 using Doppler-free laser saturation spectroscopy. Our measurements reveal the hyperfine splitting of the 5p2P1/2 state of K40, and we have determined the specific mass shift and the nuclear field shift constants for the blue (405 nm) D1 line.

  3. Three-loop reducible radiative photon contributions to Lamb shift and hyperfine splitting

    SciTech Connect

    Eides, Michael I.; Shelyuto, Valery A.

    2004-08-01

    Corrections of order {alpha}{sup 3}(Z{alpha}){sup 5}m to the Lamb shift and corrections of order {alpha}{sup 3}(Z{alpha})E{sub F} to the hyperfine splitting, generated by insertion of the three-loop one-particle reducible diagrams with radiative photons in the electron line, are calculated. The calculations are performed in the Yennie gauge.

  4. Frequency tuning of the optical delay in cesium D{sub 2} line including hyperfine structure

    SciTech Connect

    Anderson, Monte D.; Perram, Glen P.

    2010-03-15

    The frequency dependence of optical delays in both the wings and core of the cesium 6 {sup 2}S{sub 1/2}-6 {sup 2}P{sub 3/2} transition have been observed and modeled with a Voigt line shape convolved with the six hyperfine components. Tunable delays of 0-37 ns are achieved by tuning the laser frequency through resonance at various vapor pressures of 0.15-5.28 mTorr.

  5. New electron levels and classified lines in Pr II from hyperfine structure measurements

    SciTech Connect

    Furmann, B. . E-mail: furman@phys.put.poznan.pl; Stefanska, D.; Dembczynski, J.; Stachowska, E.

    2007-01-15

    Classification of 75 spectral lines (hitherto not classified) in singly ionized praseodymium (Pr II) with the use of 31 new electron levels belonging to odd configurations 4f{sup 3}5d and 4f{sup 3}6s and 14 new levels belonging to even configurations is presd. Hyperfine structure constant A and B for each new level were determined by using the method of laser-induced fluorescence in a hollow cathode discharge.

  6. Hyperfine structure and isotope shifts of transitions in neutral and singly ionized ytterbium

    NASA Technical Reports Server (NTRS)

    Berends, R. W.; Maleki, L.

    1992-01-01

    The present experimental investigation of the hyperfine structure and isotopic shifts of transitions in neutral and singly-ionized Yb, which constitute a system of some interest to microwave-frequency standards, used counterpropagating pump and probe laser beams directed through a hollow-cathode discharge lamp. The results obtained are in agreement with previous measurements except in the case of the Yb-173(+) 6 2P0 sub 3/2 state, which is more accurately determined.

  7. Investigations of ``soft-landed'' Cd surface atoms via nuclear methods: hyperfine-field sign determination

    NASA Astrophysics Data System (ADS)

    Manzhur, Y.; Zeitz, W.-D.; Prandolini, M. J.; Brewer, W. D.; Imielski, P.; Schubert, J.; Johnston, K.

    2007-10-01

    Using refined preparation techniques, cadmium guest atoms have been positioned at different sites on the surfaces of nickel crystals. The magnetic hyperfine fields and the electric field gradients at the Cd nuclei were measured by time-dependent perturbed angular correlation (TDPAC) spectroscopy of the emitted gamma radiations. By measuring the combined interactions, electric field gradients and magnetic hyperfine fields can be unambiguously attributed to each surface site. The signs of the magnetic hyperfine fields are determined by applying an external magnetic field and choosing the appropriate γ-ray detector configuration. The measured fields correlate with the number of neighbouring host atoms. Band structure calculations confirm this finding and predict magnetic fields for various sp elements from the band structure of the s-like conduction electrons. The quadrupolar interactions are manifestations of the balance in the occupation of the guest p-sublevels. These results provide new information on the structure and formation of electronic configurations of sp elements in different local environments and will contribute to understanding electronic effects on surfaces.

  8. Analysis of the competition between forbidden and hyperfine-induced transitions in Ne-like ions

    NASA Astrophysics Data System (ADS)

    Andersson, Martin; Grumer, Jon; Brage, Tomas; Zou, Yaming; Hutton, Roger

    2016-03-01

    In this work we investigate the decay of the |2 p53 s P30> state in neon-like ions along the isoelectronic sequence ranging from Z =10 to Z =35 . In the absence of a nuclear spin, the magnetic dipole transition to |2 p53 s P31> is the dominating decay channel. However, for isotopes with a nuclear spin, the interaction between the nuclear magnetic dipole moment and the electronic field introduces a mixing of |2 p53 s P31> and |P11> into the |P30> state, which in turn opens up a competing hyperfine-induced electric dipole decay channel to the ground state. This hyperfine-induced transition channel clearly dominates over the magnetic dipole channel for the neutral end of the isoelectronic sequence, when present. We give values for the rates of both these competing channels and discuss how the introduction of the hyperfine-induced transition channel could have a dramatic influence on the spectrum, not only because it introduces a new line, but also since it can substantially decrease the intensity of the magnetic dipole 2 p53 s P30→2 p53 s P31 line and affect the predicted ionization balance in different plasmas.

  9. Hyperfine structure of the metastable level in hydrogen-like atoms

    SciTech Connect

    Kolachevsky, Nikolai N

    2005-03-31

    Precision methods for measuring the hyperfine splitting E{sub HFS}(2S) of the metastable level in light hydrogen-like systems such as hydrogen, deuterium, and the {sup 3}He{sup +} ion are considered. These measurements open up a new possibility for precise testing of quantum electrodynamics (QED) of bound states in hadronic systems. While the direct calculation of the energy levels in such systems runs into the problem of the uncertainty of the nuclear charge radius, the contribution of energy corrections appearing in the calculation of the parameter D{sub 21} = 8E{sub HFS}(2S) - E{sub HFS}(1S) taking the finite size of the nucleus into account becomes smaller. The results of calculations of D{sub 21} are presented and compared with experimental values. The approach considered in the paper allows the testing of some bound-state QED corrections to the hyperfine splitting energy at a level of 10{sup -7}, which is comparable with the results of precision QED tests based on the study of the hyperfine splitting in leptonic systems. (invited paper)

  10. HYPERFINE STRUCTURE CONSTANTS OF ENERGETICALLY HIGH-LYING LEVELS OF ODD PARITY OF ATOMIC VANADIUM

    SciTech Connect

    Güzelçimen, F.; Yapıcı, B.; Demir, G.; Er, A.; Öztürk, I. K.; Başar, Gö.; Kröger, S.; Tamanis, M.; Ferber, R.; Docenko, D.; Başar, Gü. E-mail: sophie.kroeger@htw-berlin.de

    2014-09-01

    High-resolution Fourier transform spectra of a vanadium-argon plasma have been recorded in the wavelength range of 365-670 nm (15,000-27,400 cm{sup –1}). Optical bandpass filters were used in the experimental setup to enhance the sensitivity of the Fourier transform spectrometer. In total, 138 atomic vanadium spectral lines showing resolved or partially resolved hyperfine structure have been analyzed to determine the magnetic dipole hyperfine structure constants A of the involved energy levels. One of the investigated lines has not been previously classified. As a result, the magnetic dipole hyperfine structure constants A for 90 energy levels are presented: 35 of them belong to the configuration 3d {sup 3}4s4p and 55 to the configuration 3d {sup 4}4p. Of these 90 constants, 67 have been determined for the first time, with 23 corresponding to the configuration 3d {sup 3}4s4p and 44 to 3d {sup 4}4p.

  11. Calculation of radiative corrections to hyperfine splitting in p{sub 1/2} states

    SciTech Connect

    Sapirstein, J.; Cheng, K. T.

    2006-10-15

    Techniques to calculate one-loop radiative corrections to hyperfine splitting including binding corrections to all orders have been developed in the last decade for s states of atoms and ions. In this paper these methods are extended to p{sub 1/2} states for three cases. In the first case, the point-Coulomb 2p{sub 1/2} hyperfine splitting is treated for the hydrogen isoelectonic sequence, and the lowest order result ({alpha}/4{pi})E{sub F}, is shown to have large binding corrections at high Z. In the second case, neutral alkali-metal atoms are considered. In the third case, hyperfine splitting of the 2p{sub 1/2} state of lithiumlike bismuth is treated. In the latter two cases, correlation corrections are included and, in addition, the point is stressed that uncertainties associated with nuclear structure, which complicate comparison with experiment for s states, are considerably reduced because of the smaller overlap with the nucleus.

  12. Calculation of Radiative Corrections to Hyperfine Splitting in p1/2 States

    SciTech Connect

    Sapirstein, J; Cheng, K T

    2006-09-20

    Techniques to calculate one-loop radiative corrections to hyperfine splitting including binding corrections to all orders have been developed in the last decade for s states of atoms and ions. In this paper these methods are extended to p{sub 1/2} states for three cases. In the first case, the point-Coulomb 2p{sub 1/2} hyperfine splitting is treated for the hydrogen isoelectronic sequence, and the lowest order result, {alpha}/4{pi} E{sub F}, is shown to have large binding corrections at high Z. In the second case, neutral alkalis are considered. In the third case, hyperfine splitting of the 2p{sub 1/2} state of lithium-like bismuth is treated. In the latter two cases, correlation corrections are included and, in addition, the point is stressed that uncertainties associated with nuclear structure, which complicate comparison with experiment for s states, are considerably reduced because of the smaller overlap with the nucleus.

  13. Hyperfine interactions in the ground states of titanium monoxide and mononitride

    SciTech Connect

    Fletcher, D.A.; Scurlock, C.T.; Jung, K.Y.; Steimle, T.C. )

    1993-09-15

    A comparative study of the hyperfine interactions in the [ital X] [sup 2][Sigma][sup +] state of TiN and the [ital X] [sup 3][Delta] state of TiO has been performed. The [sup 48]Ti[sup 14]N([ital I]=1) hyperfine structure was determined from the analysis of 19 components of the [ital N]=1--0 and [ital N]=2--1 pure rotational transitions recorded using the pump/probe microwave-optical double resonance technique. The [sup 47]Ti([ital I]=5/2) hyperfine structure of [ital X] [sup 2][Sigma][sup +] TiN was determined from an analysis of the high resolution optical spectrum of the (0,0) [ital A] [sup 2][Pi][sub 3/2]--[ital X] [sup 2][Sigma][sup +] band system. The resulting parameters are (in MHz) [ital B]([sup 48]Ti[sup 14]N)=18 589.3513(13), [ital D]([sup 48]Ti[sup 14]N)=0.026 31(18), [gamma]([sup 48]Ti[sup 14]N)=[minus]52.2070(13), [ital b][sub [ital F

  14. Hyperfine Quantum Beat Spectroscopy of the Cs 8p level with Pulsed Pump-Probe Technique

    NASA Astrophysics Data System (ADS)

    Bayram, Burcin; Popov, Oleg; Kelly, Stephen; Boyle, Patrick; Salsman, Andrew

    2013-05-01

    Quantum beats arising from the hyperfine interaction were measured in a three-level excitation (lambda) scheme: pump for the 6s2S1 / 2 --> 8p2P3 / 2 and stimulated emission pump (probe) for the 8p2P3 / 2 --> 5d2D5 / 2 transitions of atomic cesium. In the technique, pump laser instantaneously excites the hot atomic vapor and creates anisotropy in the 8p2P3 / 2 level, and probe laser comes after some time delay. Delaying the probe time allows us to map out the motion of the polarized atoms like a stroboscope. According to the observed evolution of the hyperfine structure dependent parameters, e.g. alignment and atomic polarization, by delaying the arrival time of the stimulated emission pump laser (SEP), precise values of the magnetic dipole and electric quadrupole coefficients are obtained with an improved precision over previous results. The usefulness of the PUMP-SEP excitation scheme for the polarization hyperfine quantum beat measurements without complications from the Doppler effect will also be discussed. The financial support of the Research Corporation under the Grant number CC7133 and MiamiUniversity, College of the Arts and Sciences are acknowledged.

  15. Energy-Level Related Nuclear-Spin Effects and Super-Hyperfine Spectral Patterns: how Molecules do Self-Nmr

    NASA Astrophysics Data System (ADS)

    Harter, William; Mitchell, Justin

    2009-06-01

    At several points in his defining works on molecular spectroscopy, Herzberg notes that ``because nuclear moments ldots are so very slight ldots transitions between species ldots are very strictly forbiddenldots '' Herzberg's most recent statement of such selection rules pertained to spherical top spin-species. It has since been shown that spherical top species (as well as those of lower symmetry molecules) converge exponentially with momentum quanta J and K to degenerate level clusters wherein even ``very slight'' nuclear fields and moments cause pervasive resonance and total spin species mixing. Ultra-high resolution spectra of Borde, et .al and Pfister et .al shows how SF_6 and SiF_4 Fluorine nuclear spin levels rearrange from total-spin multiplets to NMR-like patterns as their superfine structure converges. Similar super-hyperfine effects are anticipated for lower symmetry molecules exhibiting converging superfine level-clusters. Examples include PH_3 molecules and asymmetric tops. Following this we consider models that treat nuclear spins as coupled rotors undergoing generalized Hund-case transitions from spin-lab-momentum coupling to various spin-rotor correlations. G. A. Herzberg, Electronic Spectra of Polyatomic Molecules, (Von Norstrand Rheinhold 1966) p. 246. W G. Harter and C. W Patterson, Phys. Rev. A 19, 2277 (1979) W. G. Harter, Phys. Rev. A 24, 192 (1981). Ch. J. Borde, J. Borde, Ch. Breant, Ch. Chardonnet, A. Van Lerberghe, and Ch. Salomon, in Laser Spectroscopy VII, T. W Hensch and Y. R. Shen, eds. (Springer-Verlag, Berlin, 1985). O. Pfister, F. Guernet, G. Charton, Ch. Chardonnet, F. Herlemont, and J. Legrand, J. Opt. Soc. Am. B 10, 1521 (1993). O. Pfister, Ch. Chardonnet, and Ch. J. Bordè, Phys. Rev. Lett. 76, 4516 (1996) S. N. Yurchenko, W. Thiel, S. Patchkovskii, and P. Jensen, Phys. Chem. Chem. Phys.7, 573 (2005)

  16. Raman transitions between hyperfine clock states in a magnetic trap

    NASA Astrophysics Data System (ADS)

    Naber, J. B.; Torralbo-Campo, L.; Hubert, T.; Spreeuw, R. J. C.

    2016-07-01

    We present our experimental investigation of an optical Raman transition between the magnetic clock states of 87Rb in an atom chip magnetic trap. The transfer of atomic population is induced by a pair of diode lasers which couple the two clock states off-resonantly to an intermediate state manifold. This transition is subject to destructive interference of two excitation paths, which leads to a reduction of the effective two-photon Rabi frequency. Furthermore, we find that the transition frequency is highly sensitive to the intensity ratio of the diode lasers. Our results are well described in terms of light shifts in the multilevel structure of 87Rb. The differential light shifts vanish at an optimal intensity ratio, which we observe as a narrowing of the transition linewidth. We also observe the temporal dynamics of the population transfer and find good agreement with a model based on the system's master equation and a Gaussian laser beam profile. Finally, we identify several sources of decoherence in our system, and discuss possible improvements.

  17. Decoherence of an exchange qubit by hyperfine interaction

    NASA Astrophysics Data System (ADS)

    Hung, Jo-Tzu; Fei, Jianjia; Friesen, Mark; Hu, Xuedong

    2014-07-01

    We study three-electron-spin decoherence in a semiconductor triple quantum dot with a linear geometry. The three electron spins are coupled by exchange interactions J12 and J23, and we clarify inhomogeneous and homogeneous dephasing dynamics for a logical qubit encoded in the (S =1/2,Sz=1/2) subspace. We first justify that qubit leakage via the fluctuating Overhauser field can be effectively suppressed by sufficiently large Zeeman and exchange splittings. In both J12=J23 and J12≠J23 regimes, we construct an effective pure dephasing Hamiltonian with the Zeeman splitting EZ≫J12,J23. Both effective Hamiltonians have the same order of magnitude as that for a single-spin qubit, and the relevant dephasing time scales (T2*,TFID, etc.) are of the same order as those for a single spin. We provide estimates of the dynamics of three-spin free induction decay, the decay of a Hahn spin echo, and the decay of echoes from a CPMG pulse sequence for GaAs quantum dots.

  18. Magnetic couplings in the chemical shift of paramagnetic NMR.

    PubMed

    Vaara, Juha; Rouf, Syed Awais; Mareš, Jiří

    2015-10-13

    We apply the Kurland-McGarvey (J. Magn. Reson. 1970, 2, 286) theory for the NMR shielding of paramagnetic molecules, particularly its special case limited to the ground-state multiplet characterized by zero-field splitting (ZFS) interaction of the form S·D·S. The correct formulation for this problem was recently presented by Soncini and Van den Heuvel (J. Chem. Phys. 2013, 138, 054113). With the effective electron spin quantum number S, the theory involves 2S+1 states, of which all but one are low-lying excited states, between which magnetic couplings take place by Zeeman and hyperfine interactions. We investigate these couplings as a function of temperature, focusing on both the high- and low-temperature behaviors. As has been seen in work by others, the full treatment of magnetic couplings is crucial for a realistic description of the temperature behavior of NMR shielding up to normal measurement temperatures. At high temperatures, depending on the magnitude of ZFS, the effect of magnetic couplings diminishes, and the Zeeman and hyperfine interactions become effectively averaged in the thermally occupied states of the multiplet. At still higher temperatures, the ZFS may be omitted altogether, and the shielding properties may be evaluated using a doublet-like formula, with all the 2S+1 states becoming effectively degenerate at the limit of vanishing magnetic field. We demonstrate these features using first-principles calculations of Ni(II), Co(II), Cr(II), and Cr(III) complexes, which have ZFS of different sizes and signs. A non-monotonic inverse temperature dependence of the hyperfine shift is predicted for axially symmetric integer-spin systems with a positive D parameter of ZFS. This is due to the magnetic coupling terms that are proportional to kT at low temperatures, canceling the Curie-type 1/kT prefactor of the hyperfine shielding in this case. PMID:26574272

  19. Determination of the hyperfine structure constants of the 87Rb and 85Rb 4 D5 /2 state and the isotope hyperfine anomaly

    NASA Astrophysics Data System (ADS)

    Wang, Jie; Liu, Huifeng; Yang, Guang; Yang, Baodong; Wang, Junmin

    2014-11-01

    The hyperfine structure (hfs) splittings of the 4 D5 /2 state for two isotopes of 87Rb and 85Rb atoms are measured based on double-resonance optical pumping spectra in a 5 S1 /2-5 P3 /2-4 D5 /2 ladder-type atomic system. The frequency calibration is performed by employing a wideband fiber-pigtailed phase-type electro-optic modulator together with a Fabry-Pérot cavity to cancel the error arising from nonlinear frequency scanning. The hfs magnetic dipole constant A of the 4 D5 /2 state is determined to be -16.801 ± 0.005 MHz for 87Rb and -4.978 ± 0.004 MHz for 85Rb . The hfs electric quadrupole constant B of the 4 D5 /2 state is determined to be 3.645 ± 0.030 MHz for 87Rb and 6.560 ± 0.052 MHz for 85Rb . The values of A and B for the 87Rb4 D5 /2 state are twice as accurate as previous work with thermal atoms using a femtosecond laser comb and the values of A and B for the 85Rb4 D5 /2 state are 3 times and 25 times more accurate than previous work in laser-cooled atoms using Fabry-Pérot interferometer, respectively. According to this high precision of the hfs constants and the previously measured nuclear g factors of the two isotopes, the value of the d -electron hyperfine anomaly 87Δ85(4 D5 /2 ) is derived to be -0.0041 ± 0.0009.

  20. Supertransferred hyperfine fields at {sup 7}Li: Variable temperature {sup 7}Li NMR studies of LiMn{sub 2}O{sub 4}-based spinels

    SciTech Connect

    Gee, B.; Horne, C.R.; Cairns, E.J.; Reimer, J.A. |

    1998-12-10

    The temperature dependence of the {sup 7}Li NMR shift was measured for LiMn{sub 2}O{sub 4}, LiMn{sub 2{minus}y}Ni{sub y}O{sub 4} (y = 0.1, 0.25, 0.33), LiMn{sub 2{minus}y}Co{sub y}O{sub 4} (y = 0.25, 0.5, 1.0), Li[Mn{sub 2{minus}y}Li{sub y}]O{sub 4} (y = 0.1, 0.33), and {lambda}-MnO{sub 2} spinel oxides. The {sup 7}Li NMR shift can be separated into temperature-independent and -dependent components. The temperature-dependent shift follows the Curie-Weiss behavior of the bulk magnetic susceptibility. The temperature-independent shift is attributed to contributions from van Vleck and diamagnetic susceptibilities. Pauli susceptibility may also contribute to the temperature-independent shift in the nickel- and cobalt-substituted spinels. Supertransferred hyperfine (STH) coupling constants were derived from the {sup 7}Li NMR shifts and bulk magnetic susceptibility data. The progressive increase in average nominal manganese oxidation state from +3.5 to +4 results in an increase in the supertransferred hyperfine field at the {sup 7}Li nucleus in the lithium-substituted samples. Replacement of manganese by either cobalt or nickel also results in a larger STH field at the {sup 7}Li nuclei. The increase in STH field for the lithium-, nickel-, and cobalt-substituted spinel oxides may arise from a greater covalence in these materials relative to the parent LiMn{sub 2}O{sub 4} spinel oxide.

  1. Donor hyperfine Stark shift and the role of central-cell corrections in tight-binding theory.

    PubMed

    Usman, Muhammad; Rahman, Rajib; Salfi, Joe; Bocquel, Juanita; Voisin, Benoit; Rogge, Sven; Klimeck, Gerhard; Hollenberg, Lloyd L C

    2015-04-22

    Atomistic tight-binding (TB) simulations are performed to calculate the Stark shift of the hyperfine coupling for a single arsenic (As) donor in silicon (Si). The role of the central-cell correction is studied by implementing both the static and the non-static dielectric screenings of the donor potential, and by including the effect of the lattice strain close to the donor site. The dielectric screening of the donor potential tunes the value of the quadratic Stark shift parameter (η2) from -1.3 × 10(-3) µm(2) V(-2) for the static dielectric screening to -1.72 × 10(-3) µm(2) V(-2) for the non-static dielectric screening. The effect of lattice strain, implemented by a 3.2% change in the As-Si nearest-neighbour bond length, further shifts the value of η2 to -1.87 × 10(-3) µm(2) V(-2), resulting in an excellent agreement of theory with the experimentally measured value of -1.9 ± 0.2 × 10(-3) µm(2) V(-2). Based on our direct comparison of the calculations with the experiment, we conclude that the previously ignored non-static dielectric screening of the donor potential and the lattice strain significantly influence the donor wave function charge density and thereby leads to a better agreement with the available experimental data sets. PMID:25783758

  2. On the hyperfine structures of the ground state(s) in the 6Li and 7Li atoms

    NASA Astrophysics Data System (ADS)

    Frolov, A. M.

    2016-06-01

    Hyperfine structure of the ground 22 S-states of the three-electron atoms and ions is investigated. By using our recent numerical values for the doublet electron density at the atomic nucleus we determine the hyperfine structure of the ground (doublet) 22 S-state(s) in the 6Li and 7Li atoms. Our predicted values (228.2058MHz and 803.5581MHz, respectivly) agree well with the experimental values 228.20528(8) MHz (6Li) and 803.50404(48) MHz (7Li (R.G. Schlecht and D.W. McColm, Phys. Rev. 142, 11 (1966))). The hyperfine structures of a number of lithium isotopes with short life-times, including 8Li, 9Li and 11Li atoms are also predicted. The same method is used to obtain the hyperfine structures of the three-electron 7Be+ and 9Be+ ions in their ground 22 S-states. Finally, we conclude that our approach can be generalized to describe the hyperfine structure in the triplet n 3 S-states of the four-electron atoms and ions.

  3. Isotope Shifts and Hyperfine Structure in Calcium 4snp1P1 and 4snf F Rydberg States

    SciTech Connect

    Muller, P.; Bushaw, Bruce A.; Nortershauser, Wilfried; Wendt, K.

    2000-06-01

    Isotope shifts and hyperfine structure have been measured in 4snp 1P1 and 4snf F Rydberg states for all stable calcium isotopes and the radioisotope 41Ca using high-resolution laser spectroscopy. Triple-resonance excitation via 4s2 1S0 --- 4s4p 1P1 --- 4s4d 1D2 --- Rydberg State was followed by photoionization with a CO2 laser and mass selective ion detection. Isotope shifts for the even-mass isotopes have been analyzed to derive specific mass shift and field shift factors. The apparent isotope shifts for 41Ca and 43Ca exhibit anomalous values that are n-dependent. This is interpreted in terms of hyperfine-induced fine structure mixing, which becomes very pronounced when singlet-triplet fine structure splitting is comparable to the hyperfine interaction energy. Measurements of fine structure splittings for the predominant isotope 40Ca have been used as input parameters for theoretical calculation of the perturbed hyperfine structure. Results obtained by diagonalizing the second-order hyperfine interaction matrices agree very well with experimentally observed spectra.

  4. Neutral nitrogen acceptors in ZnO: The {sup 67}Zn hyperfine interactions

    SciTech Connect

    Golden, E. M.; Giles, N. C.; Evans, S. M.; Halliburton, L. E.

    2014-03-14

    Electron paramagnetic resonance (EPR) is used to characterize the {sup 67}Zn hyperfine interactions associated with neutral nitrogen acceptors in zinc oxide. Data are obtained from an n-type bulk crystal grown by the seeded chemical vapor transport method. Singly ionized nitrogen acceptors (N{sup −}) initially present in the crystal are converted to their paramagnetic neutral charge state (N{sup 0}) during exposure at low temperature to 442 or 633 nm laser light. The EPR signals from these N{sup 0} acceptors are best observed near 5 K. Nitrogen substitutes for oxygen ions and has four nearest-neighbor cations. The zinc ion along the [0001] direction is referred to as an axial neighbor and the three equivalent zinc ions in the basal plane are referred to as nonaxial neighbors. For axial neighbors, the {sup 67}Zn hyperfine parameters are A{sub ‖} = 37.0 MHz and A{sub ⊥} = 8.4 MHz with the unique direction being [0001]. For nonaxial neighbors, the {sup 67}Zn parameters are A{sub 1} = 14.5 MHz, A{sub 2} = 18.3 MHz, and A{sub 3} = 20.5 MHz with A{sub 3} along a [101{sup ¯}0] direction (i.e., in the basal plane toward the nitrogen) and A{sub 2} along the [0001] direction. These {sup 67}Zn results and the related {sup 14}N hyperfine parameters provide information about the distribution of unpaired spin density at substitutional neutral nitrogen acceptors in ZnO.

  5. Effect of thermal history on Mossbauer signature and hyperfine interaction parameters of copper ferrite

    SciTech Connect

    Modi, K. B. Raval, P. Y.; Dulera, S. V.; Kathad, C. R.; Shah, S. J.; Trivedi, U. N.; Chandra, Usha

    2015-06-24

    Two specimens of copper ferrite, CuFe{sub 2}O{sub 4}, have been synthesized by double sintering ceramic technique with different thermal history i.e. slow cooled and quenched. X-ray diffractometry has confirmed single phase fcc spinel structure for slow cooled sample while tetragonal distortion is present in quenched sample. Mossbauer spectral analysis for slow-cooled copper ferrite reveals super position of two Zeeman split sextets along with paramagnetic singlet in the centre position corresponds to delafossite (CuFeO{sub 2}) phase that is completely absent in quenched sample. The hyperfine interaction parameters are highly influenced by heat treatment employed.

  6. Environmental Factors Influencing the Hyperfine Structure of Manganous Low-Temperature Electron Paramagnetic Resonance Spectra

    PubMed Central

    Nebert, D. W.; Allen, B. T.

    1966-01-01

    Hyperfine structure is observed in low temperature (T = -180°C) EPR (electron paramagnetic resonance) spectra of a number of solutions containing Mn++ ions 13, 15) which have characteristics in common with low temperature EPR spectra from biological substances such as mitochondria and microsomes (1-4). This investigation is an attempt to understand the features of these signals in terms of the molecular environment of the manganous ion, and a qualitative explanation for the observations reported here is advanced in terms of the amount of axial distortion of a manganese hydrate in different environments. PMID:4289642

  7. Limitation of electron mobility from hyperfine interaction in ultraclean quantum wells and topological insulators

    NASA Astrophysics Data System (ADS)

    Tarasenko, S. A.; Burkard, Guido

    2016-07-01

    The study of electron transport and scattering processes limiting electron mobility in high-quality semiconductor structures is central to solid-state electronics. Here, we uncover an unavoidable source of electron scattering which is caused by fluctuations of nuclear spins. We calculate the momentum relaxation time of electrons in quantum wells governed by the hyperfine interaction between electrons and nuclei and show that this time depends greatly on the spatial correlation of nuclear spins. Moreover, the scattering processes accompanied by a spin flip are a source of the backscattering of Dirac fermions at conducting surfaces of topological insulators.

  8. New approach to hyperfine structure - Application to the Li ground state

    NASA Technical Reports Server (NTRS)

    Bhatia, A. K.; Sucher, J.

    1980-01-01

    Global identities for delta functions, given by Hiller, Sucher and Feinberg (HSF) are applied to the calculation of the hyperfine structure (HFS) of the ground state of Li. It is shown that use of the HSF identity together with configuration interaction type wavefunctions can yield values of the HFS constant f which are comparable in accuracy to that obtained by Larsson with a 100-term Hylleraas-type wavefunction. The implications of this result for HFS calculations for atoms with many electrons are discussed.

  9. Application of the laser ion source for isotope shift and hyperfine structure investigations

    NASA Astrophysics Data System (ADS)

    Barzakh, A. E.; Chubukov, I. Ya.; Fedorov, D. V.; Panteleev, V. N.; Seliverstov, M. D.; Volkov, Yu. M.

    1998-12-01

    A high-efficient method for measuring isotope shifts and hyperfine structures in optical transitions of radioactive atoms is presented. The method is based on application of laser resonance ionization in the mass-separator ion source. The sensitivity of the method is determined by a high efficiency of the laser ion source and low background of the detection system, making use of counting α-particles following the decay of the isotope under investigation. The possibilities of this method are shown in the experiment with 155Yb and 154Tm (I=9). The isotope shifts and electromagnetic moments have been measured.

  10. High-Fidelity Quantum Logic Gates Using Trapped-Ion Hyperfine Qubits

    NASA Astrophysics Data System (ADS)

    Ballance, C. J.; Harty, T. P.; Linke, N. M.; Sepiol, M. A.; Lucas, D. M.

    2016-08-01

    We demonstrate laser-driven two-qubit and single-qubit logic gates with respective fidelities 99.9(1)% and 99.9934(3)%, significantly above the ≈99 % minimum threshold level required for fault-tolerant quantum computation, using qubits stored in hyperfine ground states of calcium-43 ions held in a room-temperature trap. We study the speed-fidelity trade-off for the two-qubit gate, for gate times between 3.8 μ s and 520 μ s , and develop a theoretical error model which is consistent with the data and which allows us to identify the principal technical sources of infidelity.

  11. Hyperfine resonance of gaseous atomic hydrogen at 4.2 K

    NASA Technical Reports Server (NTRS)

    Crampton, S. B.; Kleppner, D.; Phillips, W. D.; Weinrib, A.; Greytak, T. J.; Smith, D. A.

    1979-01-01

    The hyperfine frequency and wall shift of hydrogen atoms at 4.2 K stored in a bulb coated with solid H2 were measured. The phase shift per wall collision is -0.29(1) rad. The adsorption energy of H on H2 is 9(2) K, and the adsorption time at 4.2 K is approximately 30 nsec. Transverse and longitudinal relaxation times have been measured, and atomic densities greater than 10 to the 14th/cu cm have been observed.

  12. Isotope shift and hyperfine splitting of the 4s{yields}5p transition in potassium

    SciTech Connect

    Behrle, Alexandra; Koschorreck, Marco; Koehl, Michael

    2011-05-15

    We have investigated the 4s {sup 2}S{sub 1/2}{yields}5p {sup 2}P{sub 1/2} transition (D{sub 1} line) of the potassium isotopes {sup 39}K, {sup 40}K, and {sup 41}K using Doppler-free laser saturation spectroscopy. Our measurements reveal the hyperfine splitting of the 5p {sup 2}P{sub 1/2} state of {sup 40}K, and we have determined the specific mass shift and the nuclear field shift constants for the blue (405 nm) D{sub 1} line.

  13. Sensitivity of hyperfine structure to nuclear radius and quark mass variation

    SciTech Connect

    Dinh, T. H.; Dunning, A.; Dzuba, V. A.; Flambaum, V. V.

    2009-05-15

    To search for the temporal variation in the fundamental constants, one needs to know dependence of atomic transition frequencies on these constants. We study the dependence of the hyperfine structure of atomic s levels on nuclear radius and, via radius, on quark masses. An analytical formula has been derived and tested by the numerical relativistic Hartree-Fock calculations for Rb, Cd{sup +}, Cs, Yb{sup +}, and Hg{sup +}. The results of this work allow the use of the results of past and future atomic clock experiments and quasar spectra measurements to put constraints on time variation in the quark masses.

  14. A Perturbed-Angular-Correlation Study of Hyperfine Interactions at 181Ta in α-Fe2O3

    NASA Astrophysics Data System (ADS)

    Pasquevich, A. F.; Junqueira, A. C.; Carbonari, A. W.; Saxena, R. N.

    2004-11-01

    The hyperfine interactions at 181Ta ions on Fe3+ sites in α-Fe2O3 (hematite) were studied in the temperature range 11 1100 K by means of the perturbed angular correlation (PAC) technique. The 181Hf(β-)181Ta probe nuclei were introduced chemically into the sample during the preparation. The hyperfine interaction measurements allow to observe the magnetic phase transition and to characterize the supertransferred hyperfine magnetic field Bhf and the electric field gradient (EFG) at the impurity sites. The angles between Bhf and the principal axes of the EFG were determined. The Morin transition was also observed. The results are compared with those of similar experiments carried out using 111Cd probe.

  15. Effect of the Nuclear Hyperfine Field on the 2D Electron Conductivity in the Quantum Hall Regime

    SciTech Connect

    VITKALOV,S.A.; BOWERS,C.R.; SIMMONS,JERRY A.; RENO,JOHN L.

    2000-07-13

    The effect of the nuclear hyperfine interaction on the dc conductivity of 2D electrons under quantum Hall effect conditions at filling factor v= 1 is observed for the first time. The local hyperfine field enhanced by dynamic nuclear polarization is monitored via the Overhauser shift of the 2D conduction electron spin resonance in AlGaAs/GaAs multiquantum-well samples. The experimentally observed change in the dc conductivity resulting from dynamic nuclear polarization is in agreement with a thermal activation model incorporating the Zeeman energy change due to the hyperfine interaction. The relaxation decay time of the dc conductivity is, within experimental error, the same as the relaxation time of the nuclear spin polarization determined from the Overhauser shift. These findings unequivocally establish the nuclear spin origins of the observed conductivity change.

  16. Experimental and ab initio study of the hyperfine parameters of ZnFe 2 O 4 with defects

    NASA Astrophysics Data System (ADS)

    Quintero, J. Melo; Salcedo Rodríguez, K. L.; Pasquevich, G. A.; Zélis, P. Mendoza; Stewart, S. J.; Rodríguez Torres, C. E.; Errico, L. A.

    2016-12-01

    We present a combined Mössbauer and ab initio study on the influence of oxygen-vacancies on the hyperfine and magnetic properties of the ZnFe 2 O 4 spinel ferrite. Samples with different degree of oxygen-vacancies were obtained from zinc ferrite powder that was thermally treated at different temperatures up to 650 ∘C under vacuum.Theoretical calculations of the hyperfine parameters, magnetic moments and magnetic alignment have been carried out considering different defects such as oxygen vacancies and cation inversion. We show how theoretical and experimental approaches are complementary to characterize the local structure around Fe atoms and interpret the observed changes in the hyperfine parameters as the level of defects increases.

  17. Hyperfine and Nuclear Quadrupole Tensors of Nitrogen Donors in the QA Site of Bacterial Reaction Centers: Correlation of the Histidine Nδ Tensors with Hydrogen Bond Strength

    PubMed Central

    2015-01-01

    X- and Q-band pulsed EPR spectroscopy was applied to study the interaction of the QA site semiquinone (SQA) with nitrogens from the local protein environment in natural abundance 14N and in 15N uniformly labeled photosynthetic reaction centers of Rhodobacter sphaeroides. The hyperfine and nuclear quadrupole tensors for His-M219 Nδ and Ala-M260 peptide nitrogen (Np) were estimated through simultaneous simulation of the Q-band 15N Davies ENDOR, X- and Q-band 14,15N HYSCORE, and X-band 14N three-pulse ESEEM spectra, with support from DFT calculations. The hyperfine coupling constants were found to be a(14N) = 2.3 MHz, T = 0.3 MHz for His-M219 Nδ and a(14N) = 2.6 MHz, T = 0.3 MHz for Ala-M260 Np. Despite that His-M219 Nδ is established as the stronger of the two H-bond donors, Ala-M260 Np is found to have the larger value of a(14N). The nuclear quadrupole coupling constants were estimated as e2Qq/4h = 0.38 MHz, η = 0.97 and e2Qq/4h = 0.74 MHz, η = 0.59 for His-M219 Nδ and Ala-M260 Np, respectively. An analysis of the available data on nuclear quadrupole tensors for imidazole nitrogens found in semiquinone-binding proteins and copper complexes reveals these systems share similar electron occupancies of the protonated nitrogen orbitals. By applying the Townes–Dailey model, developed previously for copper complexes, to the semiquinones, we find the asymmetry parameter η to be a sensitive probe of the histidine Nδ–semiquinone hydrogen bond strength. This is supported by a strong correlation observed between η and the isotropic coupling constant a(14N) and is consistent with previous computational works and our own semiquinone-histidine model calculations. The empirical relationship presented here for a(14N) and η will provide an important structural characterization tool in future studies of semiquinone-binding proteins. PMID:25026433

  18. Orbital hyperfine interaction and qubit dephasing in carbon nanotube quantum dots

    NASA Astrophysics Data System (ADS)

    Palyi, Andras; Csiszar, Gabor

    2015-03-01

    Hyperfine interaction (HF) is of key importance for the functionality of solid-state quantum information processing, as it affects qubit coherence and enables nuclear-spin quantum memories. In this work, we complete the theory of the basic hyperfine interaction mechanisms (Fermi contact, dipolar, orbital) in carbon nanotube quantum dots by providing a theoretical description of the orbital HF. We find that orbital HF induces an interaction between the nuclear spins of the nanotube lattice and the valley degree of freedom of the electrons confined in the quantum dot. We show that the resulting nuclear-spin-electron-valley interaction (i) is approximately of Ising type, (ii) is essentially local, in the sense that an effective atomic interaction strength can be defined, and (iii) has a strength that is comparable to the combined strength of Fermi contact and dipolar interactions. We argue that orbital HF provides a new decoherence mechanism for single-electron valley qubits and spin-valley qubits in a range of multi-valley materials. We explicitly evaluate the corresponding inhomogeneous dephasing time T2* for a nanotube-based valley qubit. We acknowledge funding from the EU Marie Curie CIG-293834, OTKA Grant PD 100373, and EU ERC Starting Grant CooPairEnt 258789. AP is supported by the Janos Bolyai Scholarship of the Hungarian Academy of Sciences.

  19. Blackbody radiation shift of the {sup 133}Cs hyperfine transition frequency

    SciTech Connect

    Micalizio, Salvatore; Godone, Aldo; Calonico, Davide; Levi, Filippo; Lorini, Luca

    2004-05-01

    We report the theoretical evaluations of the static scalar polarizability of the {sup 133}Cs ground state and of the blackbody radiation shift induced on the transition frequency between the two hyperfine levels with m{sub F}=0. This shift is of fundamental importance in the evaluation of the accuracy of the primary frequency standards based on atomic fountains and is employed in the realization of the SI second in the International Atomic Time scale at the level of 1x10{sup -15}. Our computed value for the polarizability is {alpha}{sub 0}=(6.600{+-}0.016)x10{sup -39}C m{sup 2}/V in agreement at the level of 1x10{sup -3} with recent theoretical and experimental values. As regards the blackbody radiation shift we find for the relative hyperfine transition frequency {beta}=(-1.49{+-}0.07)x10{sup -14} at T=300 K in agreement with frequency measurements reported by our group and by Bauch and Schroeder [Phys. Rev. Lett. 78, 622 (1997)]. This value is lower by 2x10{sup -15} than that obtained with measurements based on the dc Stark shift and than the value commonly accepted up to now.

  20. Diamagnetic correction to the {sup 9}Be{sup +} ground-state hyperfine constant

    SciTech Connect

    Shiga, N.; Itano, W. M.; Bollinger, J. J.

    2011-07-15

    We report an experimental determination of the diamagnetic correction to the {sup 9}Be{sup +} ground state hyperfine constant A. We measured A = -625 008 837.371(11) Hz at a magnetic field B of 4.4609 T. Comparison with previous results, obtained at lower values of B (0.68 T and 0.82 T), yields the diamagnetic shift coefficient k = 2.63(18)x10{sup -11} T{sup -2}, where A(B)=A{sub 0}(1+kB{sup 2}). The zero-field hyperfine constant A{sub 0} is determined to be -625 008 837.044(12) Hz. The g-factor ratio g{sub I}{sup '}/g{sub J} is determined to be 2.134 779 852 7(10)x10{sup -4}, which is equal to the value measured at lower B to within experimental error. Upper limits are placed on some other corrections to the Breit-Rabi formula. The measured value of k agrees with theoretical estimates.

  1. Optical pumping and readout of bismuth hyperfine states in silicon for atomic clock applications

    PubMed Central

    Saeedi, K.; Szech, M.; Dluhy, P.; Salvail, J.Z.; Morse, K.J.; Riemann, H.; Abrosimov, N.V.; Nötzel, N.; Litvinenko, K.L.; Murdin, B.N.; Thewalt, M.L.W.

    2015-01-01

    The push for a semiconductor-based quantum information technology has renewed interest in the spin states and optical transitions of shallow donors in silicon, including the donor bound exciton transitions in the near-infrared and the Rydberg, or hydrogenic, transitions in the mid-infrared. The deepest group V donor in silicon, bismuth, has a large zero-field ground state hyperfine splitting, comparable to that of rubidium, upon which the now-ubiquitous rubidium atomic clock time standard is based. Here we show that the ground state hyperfine populations of bismuth can be read out using the mid-infrared Rydberg transitions, analogous to the optical readout of the rubidium ground state populations upon which rubidium clock technology is based. We further use these transitions to demonstrate strong population pumping by resonant excitation of the bound exciton transitions, suggesting several possible approaches to a solid-state atomic clock using bismuth in silicon, or eventually in enriched 28Si. PMID:25990870

  2. Ab initio electron affinity and hyperfine structure constants of ^231Pa:

    NASA Astrophysics Data System (ADS)

    Dinov, Konstantin D.; Beck, Donald R.

    1996-05-01

    We have performed valence shell Relativistic Configuration Interaction calculations(Konstantin D. Dinov and Donald R. Beck, Electron affinity and hyperfine structure constants of Pa^-: 7p attachment.) Submitted to Phys. Rev. A for the Electron Affinity (EA) of ^231Pa. Our result of 0.222 eV for the binding energy of the Pa^- 5f^2 6d 7s^2 7p J=6 state is consistent with the experimental yield(X-L. Zhao, M-J. Nadeau, M.A. Garwan, L.R. Kilius and A.E. Litherland, Nuc. Instr. Meth. B 92), 258-64 (1994). Our result for the hyperfine structure constants of Pa^-, is the first available ab initio result. No other bound states were found for the 7p attachment. We didn't find evidence to support possible 5d attachment in this system. This work extends our previous calculations for the Rare Earth negative ions(K.D. Dinov and D.R. Beck, Phys. Rev. A 52) , 2632-37 (1995); K. Dinov and D.R. Beck, Phys. Rev. A 51 (2), 1680-82 (1995); K. Dinov, D.R. Beck and D. Datta, Phys. Rev. A 50 (2), 1144-48 (1994).

  3. Hyperfine excitation of CN by para- and ortho-H2

    NASA Astrophysics Data System (ADS)

    Kalugina, Yulia; Lique, François

    2015-01-01

    Among the interstellar molecules, the CN radical is of particular interest since it is a good probe of cold dark molecular clouds, and especially prestellar cores. Modelling of CN emission spectra from these dense molecular clouds requires the calculation of rate coefficients for excitation by collisions with the most abundant species. We calculate fine- and hyperfine-structure-resolved excitation rate coefficients of CN(X2Σ+) by para- and ortho-H2. The calculations are based on a new potential energy surface obtained recently from highly correlated ab initio calculations. State-to-state rate coefficients between fine and hyperfine levels of CN were calculated for low temperatures ranging from 5 to 100 K. The new results are compared to available CN rate coefficients. Significant differences are found between the different sets of rate coefficients. This comparison shows that the new CN-H2 rate coefficients have to be used for observations interpretations. We expect that their use will help significantly to have a new insight into the physical conditions of prestellar cores.

  4. Role of quantum confinement and hyperfine splitting in lithium-doped ZnO nanocrystals

    NASA Astrophysics Data System (ADS)

    Kwak, Hyunwook; Tiago, Murilo L.; Chan, Tzu-Liang; Chelikowsky, James R.

    2008-11-01

    The role of quantum confinement on the electronic properties of Li interstitial impurities in ZnO nanocrystals was examined using a real-space pseudopotential-density-functional method. The Li impurity was found to be partially ionized resulting in a significant charge transfer around the impurity site. To calculate the hyperfine interaction for this system using pseudopotentials, we modified Van de Walle and Blöchl’s method to include explicitly the off-site contribution of the Li impurity wave function. Our modifications dramatically enhanced the agreement between the calculated and the measured isotropic hyperfine splitting constants. Our analysis with an effective-mass model demonstrates that the partial ionization of the impurity atom plays an important role both in the binding energy and in the shape of its wave function. Comparison between calculations using the local-density approximation (LDA) with LDA+U indicates that the local Coulomb correlation does not play a significant role in altering the impurity electronic states of interstitial Li-doped ZnO nanocrystals.

  5. Assignment of 1H and 13C hyperfine-shifted resonances for tuna ferricytochrome c.

    PubMed Central

    Sukits, S F; Satterlee, J D

    1996-01-01

    Tuna ferricytochrome c has been used to demonstrate the potential for completely assigning 1H and 13C strongly hyperfine-shifted resonances in metalloprotein paramagnetic centers. This was done by implementation of standard two-dimensional NMR experiments adapted to take advantage of the enhanced relaxation rates of strongly hyperfine-shifted nuclei. The results show that complete proton assignments of the heme and axial ligands can be achieved, and that assignments of several strongly shifted protons from amino acids located close to the heme can also be made. Virtually all proton-bearing heme 13C resonances have been located, and additional 13C resonances from heme vicinity amino acids are also identified. These results represent an improvement over previous proton resonance assignment efforts that were predicated on the knowledge of specific assignments in the diamagnetic protein and relied on magnetization transfer experiments in heterogeneous solutions composed of mixtures of diamagnetic ferrocytochrome c and paramagnetic ferricytochrome c. Even with that more complicated procedure, complete heme proton assignments for ferricytochrome c have never been demonstrated by a single laboratory. The results presented here were achieved using a more generally applicable strategy with a solution of the uniformly oxidized protein, thereby eliminating the requirement of fast electron self-exchange, which is a condition that is frequently not met. PMID:8913622

  6. Frequency swept microwaves for hyperfine decoupling and time domain dynamic nuclear polarization.

    PubMed

    Hoff, Daniel E M; Albert, Brice J; Saliba, Edward P; Scott, Faith J; Choi, Eric J; Mardini, Michael; Barnes, Alexander B

    2015-11-01

    Hyperfine decoupling and pulsed dynamic nuclear polarization (DNP) are promising techniques to improve high field DNP NMR. We explore experimental and theoretical considerations to implement them with magic angle spinning (MAS). Microwave field simulations using the high frequency structural simulator (HFSS) software suite are performed to characterize the inhomogeneous phase independent microwave field throughout a 198GHz MAS DNP probe. Our calculations show that a microwave power input of 17W is required to generate an average EPR nutation frequency of 0.84MHz. We also present a detailed calculation of microwave heating from the HFSS parameters and find that 7.1% of the incident microwave power contributes to dielectric sample heating. Voltage tunable gyrotron oscillators are proposed as a class of frequency agile microwave sources to generate microwave frequency sweeps required for the frequency modulated cross effect, electron spin inversions, and hyperfine decoupling. Electron spin inversions of stable organic radicals are simulated with SPINEVOLUTION using the inhomogeneous microwave fields calculated by HFSS. We calculate an electron spin inversion efficiency of 56% at a spinning frequency of 5kHz. Finally, we demonstrate gyrotron acceleration potentials required to generate swept microwave frequency profiles for the frequency modulated cross effect and electron spin inversions. PMID:26482131

  7. Hyperfine and spin-orbit dynamics in GaAs double quantum dots

    NASA Astrophysics Data System (ADS)

    Shulman, Michael; Nichol, John; Harvey, Shannon; Pal, Arijeet; Halperin, Bertrand; Umansky, Vladimir; Yacoby, Amir

    2015-03-01

    Semiconductor quantum dots provide a unique platform for single-particle physics and many-body quantum mechanics. In particular, understanding the dynamics of a single electron interacting with a nuclear spin bath is key to improving spin-based quantum information processing, since the hyperfine interaction limits the performance of many spin qubits. We probe the electron-nuclear interaction by measuring the splitting at the anti-crossing between the electron singlet (S) and m =1 triplet (T +) states in a GaAs double quantum dot. Using Landau-Zener sweeps, we find that the size of this splitting varies by more than an order of magnitude depending on the magnitude and direction of the external magnetic field. These results are consistent with a competition between the spin orbit interaction and the hyperfine interaction, even though the extracted spin orbit length is much larger than the size of the double quantum dot. We confirm these results by using Landau-Zener sweeps to measure the high-frequency correlations in the S-T + splitting that arise from the Larmor precession of the nuclei. These unexpected results have implications for improving the performance of spin-based quantum information processing, as well as improving our understanding of the central spin problem.

  8. Self-consistent calculation of hyperfine fields and adiabatic potential of impurities in iron

    NASA Astrophysics Data System (ADS)

    Kanamori, Junjiro; Akai, Hisazumi; Akai, Masako

    1984-01-01

    Hyperfine fields of impurities of the atomic number Z=1 56 at the substitutional site and those of light impurities of Z=1 9 at the interstitial sites in ferromagnetic iron are calculated by the KKR method adapted to the system containing a single impurity atom. The potential of the impurity atom is determined self-consistently by use of the local spin density functional formalism. The results for nonmagnetic sp valence impurities agree with those of the previous nonself-consistent calculation by Katayama-Yoshida, Terakura and Kanamori except for a few cases, confirming their theory of the systematic variation of hyperfine fields. The calculation for magnetic impurities of transition elements is presented for the first time in this paper. The calculations mentioned so far assume that impurities are situated at the center of each site. For the purpose of discussing the stability of the impurity positions, the change of the adiabatic potential due to displacements from the center is calculated by carrying out similar self-consistent calculations for off-center impurity positions. It is concluded that positive muon and some light impurities including boron will be displaced from the center when trapped in a vacancy.

  9. The theory of the Bohr-Weisskopf effect in the hyperfine structure

    NASA Astrophysics Data System (ADS)

    Karpeshin, F. F.; Trzhaskovskaya, M. B.

    2015-09-01

    Description of the Bohr-Wesskopf effect in the hyperfine structure of few-electron heavy ions is a challenging problem, which can be used as a test of both QED and atomic calculations. However, for twenty years the research has actually been going in a wrong direction, aimed at fighting the Bohr-Weisskopf effect through its cancellation in specific differences. Alternatively, we propose the constructive model-independent way, which enables the nuclear radii and their momenta to be retrieved from the hyper-fine splitting (HFS). The way is based on analogy of HFS to internal conversion coefficients, and the Bohr-Weisskopf effect - to the anomalies in the internal conversion coefficients. It is shown that the parameters which can be extracted from the data are the even nuclear momenta of the magnetization distribution. The radii R2 and - for the first time - R4 are obtained in this way by analysis of the experimental HFS values for the H- and Li-like ions of 209Bi. The critical prediction concerning the HFS for the 2p1/2 state is made. The present analysis shows high sensitivity of the method to the QED effects, which offers a way of precision test of QED. Experimental recommendations are given, which are aimed at retrieving data on the HFS values for a set of a few-electron configurations of each atom.

  10. High-precision hyperfine structure measurement in slow atomic ion beams by collinear laser-rf double resonance

    SciTech Connect

    Amarjit Sen, Childs, W.J.; Goodman, L.S.

    1987-01-01

    A new collinear laser-ion beam apparatus for slow ions (1 to 1.5 keV) has been built for measuring the hyperfine structure of metastable levels of ions with laser-rf double resonance technique. Narrow linewidths of approx.60 kHz (FWHM) have been observed for the first time in such systems. As a first application the hyperfine structure of the 4f/sup 7/(/sup 8/S/sup 0/)5d /sup 9/D/sub J//sup 0/ metastable levels of /sup 151,153/Eu/sup +/ has been measured with high precision. 10 refs., 8 figs.

  11. Characterization of hyperfine interaction between an NV electron spin and a first-shell 13C nuclear spin in diamond

    NASA Astrophysics Data System (ADS)

    Rao, K. Rama Koteswara; Suter, Dieter

    2016-08-01

    The nitrogen-vacancy (NV) center in diamond has attractive properties for a number of quantum technologies that rely on the spin angular momentum of the electron and the nuclei adjacent to the center. The nucleus with the strongest interaction is the 13C nuclear spin of the first shell. Using this degree of freedom effectively hinges on precise data on the hyperfine interaction between the electronic and the nuclear spin. Here, we present detailed experimental data on this interaction, together with an analysis that yields all parameters of the hyperfine tensor, as well as its orientation with respect to the atomic structure of the center.

  12. Bi donor hyperfine state populations studied by optical transitions of donor bound excitons in enriched {sup 28}Si

    SciTech Connect

    Ilkhchy, K. Saeedi; Steger, M.; Thewalt, M. L. W.; Abrosimov, N.; Riemann, H.; Becker, P.; Pohl, H.-J.

    2013-12-04

    We report on the first optical studies of Bi donor bound excitons in {sup 28}Si, using absorption rather than emission spectroscopy, and a new noncontact photoconductivity method which has much higher sensitivity and spectral resolution than photoluminescence spectroscopy. Individual hyperfine components of this potential semiconductor qubit can be resolved under an applied magnetic field, and we find that strong nonresonant optical hyperpolarization towards both the I{sub z} = +9/2 and −9/2 hyperfine states can be observed, depending on the intensity of the above-gap excitation.

  13. Normal-Mode Splitting in the Coupled System of Hybridized Nuclear Magnons and Microwave Photons.

    PubMed

    Abdurakhimov, L V; Bunkov, Yu M; Konstantinov, D

    2015-06-01

    In the weak ferromagnetic MnCO_{3} system, a low-frequency collective spin excitation (magnon) is the hybridized oscillation of nuclear and electron spins coupled through the hyperfine interaction. By using a split-ring resonator, we performed transmission spectroscopy measurements of the MnCO_{3} system and observed avoided crossing between the hybridized nuclear magnon mode and the resonator mode in the NMR-frequency range. The splitting strength is quite large due to the large spin density of ^{55}Mn, and the cooperativity value C=0.2 (the magnon-photon coupling parameter) is close to the conditions of strong coupling. The results reveal a new class of spin systems, in which the coupling between nuclear spins and photons is mediated by electron spins via the hyperfine interaction. PMID:26196633

  14. Hyperfine structure analysis in the intense spectral lines of the neutral Cu atom falling in the 353-809 nm wavelength region using a Fourier transform spectrometer

    NASA Astrophysics Data System (ADS)

    Ankush, B. K.; Deo, M. N.

    2014-02-01

    Hyperfine structure analyses have been performed in the high-resolution spectrum of the neutral copper atom covering the wavelength region of 353-809 nm using Fourier transform spectroscopy. A DC discharge of natural copper produced in a liquid nitrogen cooled hollow cathode lamp used as a light source and a photomultiplier tube as well as Si photodiodes were employed as the light detectors. The hfs studies in 17 transitions of the neutral copper atom originating from 17 energy levels for 63Cu have been reported here. The present investigation has provided the magnetic dipole coupling constant A and electric quadrupole coupling constant B for the first time for the following 6 even-parity levels lying at 49,935, 49,942 cm-1, of 3d104d configuration, 52,848 cm-1 of 3d106 s configuration, 55,387, 55,391 cm-1 3d105d configuration and 71,978 cm-1 of 3d104s4d configuration. The sign convention of the previously-reported hfs A value amounting to 1920 MHz for the level at 44,963 cm-1 of 3d94s4p configuration has been revised to -1920 MHz. Measurements reported earlier of A and B hfs constants for the 11 odd-parity energy levels also have been confirmed.

  15. {sup 33}S hyperfine interactions in H{sub 2}S and SO{sub 2} and revision of the sulfur nuclear magnetic shielding scale

    SciTech Connect

    Helgaker, Trygve; Gauss, Jürgen; Cazzoli, Gabriele Puzzarini, Cristina

    2013-12-28

    Using the Lamb-dip technique, the hyperfine structure in the rotational spectra of H{sub 2}{sup 33}S and {sup 33}SO{sub 2} has been resolved and the corresponding parameters—that is, the sulfur quadrupole-coupling and spin–rotation tensors—were determined. The experimental parameters are in good agreement with results from high-level coupled-cluster calculations, provided that up to quadruple excitations are considered in the cluster operator, sufficiently large basis sets are used, and vibrational corrections are accounted for. The {sup 33}S spin-rotation tensor for H{sub 2}S has been used to establish a new sulfur nuclear magnetic shielding scale, combining the paramagnetic part of the shielding as obtained from the spin–rotation tensor with a calculated value for the diamagnetic part as well as computed vibrational and temperature corrections. The value of 716(5) ppm obtained in this way for the sulfur shielding of H{sub 2}S is in good agreement with results from high-accuracy quantum-chemical calculations but leads to a shielding scale that is about 28 ppm lower than the one suggested previously in the literature, based on the {sup 33}S spin-rotation constant of OCS.

  16. Hyperfine fields of Fe in Nd2Fe14BandSm2Fe17N3

    NASA Astrophysics Data System (ADS)

    Akai, Hisazumi; Ogura, Masako

    2015-03-01

    High saturation magnetization of rare-earth magnets originates from Fe and the strong magnetic anisotropy stems from f-states of rare-earth elements such as Nd and Sm. Therefore the hyperfine fields of both Fe and rare-earth provide us with important pieces of information: Fe NMR enable us to detect site dependence of the local magnetic moment and magnetic anisotropy (Fe sites also contribute to the magnetic anisotropy) while rare-earth NQR directly give the information of electric field gradients (EFG) that are related to the shape of the f-electron cloud as well as the EFG produced by ligands. In this study we focus on the hyperfine fields of materials used as permanent magnets, Nd2Fe14BandSm2Fe17N3 from theoretical points of view. The detailed electronic structure together with the hyperfine interactions are discussed on the basis of the first-principles calculation. In particular, the relations between the observed hyperfine fields and the magnetic properties are studies in detail. The effects of doping of those materials by other elements such as Dy and the effects of N adding in Sm2Fe17N3 will be discussed. This work was supported by Elements Strategy Initiative Center for Magnetic Materials Project, the Ministry of Education, Culture, Sports, Science and Technology, Japan.

  17. Radiative decays of double heavy baryons in a relativistic constituent three-quark model including hyperfine mixing effects

    SciTech Connect

    Branz, Tanja; Faessler, Amand; Gutsche, Thomas; Lyubovitskij, Valery E.; Oexl, Bettina; Ivanov, Mikhail A.; Koerner, Juergen G.

    2010-06-01

    We study flavor-conserving radiative decays of double-heavy baryons using a manifestly Lorentz covariant constituent three-quark model. Decay rates are calculated and compared to each other in the full theory, keeping masses finite, and also in the heavy quark limit. We discuss in some detail hyperfine mixing effects.

  18. Hyperfine interactions in soybean and lupin oxy-leghemoglobins studied using Mössbauer spectroscopy with a high velocity resolution

    NASA Astrophysics Data System (ADS)

    Kumar, A.; Alenkina, I. V.; Zakharova, A. P.; Oshtrakh, M. I.; Semionkin, V. A.

    2015-04-01

    A comparative study of monomeric soybean and lupin leghemoglobins in the oxy-form was carried out using Mössbauer spectroscopy with a high velocity resolution at 90 K. The 57Fe hyperfine parameters of measured spectra were evaluated and compared with possible structural differences in the heme Fe(II)-O 2 bond.

  19. Finite Hypernuclei in the Latest Quark-Meson Coupling Model

    SciTech Connect

    Pierre A. M. Guichon; Anthony W. Thomas; Kazuo Tsushima

    2007-12-12

    The most recent development of the quark-meson coupling (QMC) model, in which the effect of the mean scalar field in-medium on the hyperfine interaction is also included self-consistently, is used to compute the properties of finite hypernuclei. The calculations for $\\Lambda$ and $\\Xi$ hypernuclei are of comparable quality to earlier QMC results without the additional parameter needed there. Even more significantly, the additional repulsion associated with the increased hyperfine interaction in-medium completely changes the predictions for $\\Sigma$ hypernuclei. Whereas in the earlier work they were bound by an amount similar to $\\Lambda$ hypernuclei, here they are unbound, in qualitative agreement with the experimental absence of such states. The equivalent non-relativistic potential felt by the $\\Sigma$ is repulsive inside the nuclear interior and weakly attractive in the nuclear surface, as suggested by the analysis of $\\Sigma$-atoms.

  20. Hyperfine frequencies of 87Rb and 133Cs atoms in Xe gas

    NASA Astrophysics Data System (ADS)

    McGuyer, B. H.; Xia, T.; Jau, Y.-Y.; Happer, W.

    2011-09-01

    The microwave resonant frequencies of ground-state 87Rb and 133Cs atoms in Xe buffer gas are shown to have a relatively large nonlinear dependence on the Xe pressure, presumably because of RbXe or CsXe van der Waals molecules. The nonlinear shifts for Xe are opposite in sign to the previously measured shifts for Ar and Kr, even though all three gases have negative linear shifts. The Xe data show striking discrepancies with the previous theory for nonlinear shifts. Most of this discrepancy is eliminated by accounting for the spin-rotation interaction, γN·S, in addition to the hyperfine-shift interaction, δAI·S, in the molecules. To the limit of our experimental accuracy, the shifts of 87Rb and 133Cs in He, Ne, and N2 were linear with pressure.

  1. Precision hyperfine structure spectroscopy of Be isotopes at SLOWRI prototype and prospects of SLOWRI at RIKEN

    SciTech Connect

    Wada, M.; Takamine, A.; Okada, K.; Sonoda, T.; Schury, P.; Kanai, Y.; Kojima, T. M.; Yamazaki, Y.; Yoshida, A.; Kubo, T.; Iimura, H.; Katayama, I.; Ohtani, S.; Wollnik, H.; Schuessler, H. A.

    2009-05-04

    Precision atomic spectroscopy experiments for Be isotopes have been carried out at the prototype universal slow RI-beam (SLOWRI) setup at RIKEN. Radioactive Be ions produced at 1 GeV were decelerated and thermlized in an RF-carpet ion guide. The thermalized ions were transferred to an ion trap where laser cooling was used to reduce the ion energy to the order of 1 {mu}eV. Laser microwave double resonance spectroscopy was performed for the hyperfine structure measurements of trapped and laser cooled {sup 7}Be{sup +} and {sup 11}Be{sup +} ions. Measurements of the S{sub 1/2}{yields}P{sub 1/2},P{sub 3/2} transition frequencies of {sup 7,9,10,11}Be{sup +} ions are also in progress. These results are briefly discussed. Future prospects for expanding the capability of SLOWRI is also discussed.

  2. Hyperfine splitting and the Zeeman effect in holographic heavy-light mesons

    SciTech Connect

    Herzog, Christopher P.; Stricker, Stefan A.; Vuorinen, Aleksi

    2010-08-15

    We inspect the mass spectrum of heavy-light mesons in deformed N=2 super Yang-Mills theory using the AdS/CFT correspondence. We demonstrate how some of the degeneracies of the supersymmetric meson spectrum can be removed upon breaking the supersymmetry, thus leading to the emergence of a hyperfine structure. The explicit SUSY breaking scenarios we consider involve on the one hand, tilting one of the two fundamental D7-branes inside the internal R{sup 6} space, and on the other hand, applying an external magnetic field on the (untilted) branes. The latter scenario leads to the well-known Zeeman effect, which we inspect for both weak and strong magnetic fields.

  3. Ab initio calculation of hyperfine and superhyperfine interactions for shallow donors in semiconductors.

    PubMed

    Overhof, Harald; Gerstmann, Uwe

    2004-02-27

    For the shallow group V donors in Si we show that the hyperfine interaction for the donor nucleus and the superhyperfine interactions for the first five shells of Si ligands can be quite accurately calculated using the local spin-density approximation of the density-functional theory. We treat the impurity problem in a Green's function approach. Since we have to truncate the long-ranged part of the defect potential, we do not obtain a localized gap state. Instead we identify the resonance above the conduction band with the paramagnetic defect state. We show that the hf and shf interactions thus obtained are at least as accurate as those obtained from one-electron theories with fitting parameters. Application of this first principles method to other shallow donors could be an essential help in defect identification. PMID:14995814

  4. Spin relaxation of a diffusively moving carrier in a random hyperfine field

    NASA Astrophysics Data System (ADS)

    Roundy, R. C.; Raikh, M. E.

    2014-11-01

    Relaxation, , of the average spin of a carrier in a course of hops over sites hosting random hyperfine fields is studied theoretically. In low dimensions, d =1 ,2 , the decay of average spin with time is nonexponential at all times. The origin of the effect is that for d =1 ,2 a typical random-walk trajectory exhibits numerous self-intersections. Multiple visits of the carrier to the same site accelerates the relaxation since the corresponding partial rotations of spin during these visits add up. Another consequence of self-intersections of the random-walk trajectories is that, in all dimensions, the average, , becomes sensitive to a weak magnetic field directed along z . Our analytical predictions are complemented by the numerical simulations of . The scenario of acceleration of spin relaxation due to returns applies also to the non-Markovian decoherence of a qubit surrounded by multiple fluctuators.

  5. Spin-valley qubit in nanostructures of monolayer semiconductors: Optical control and hyperfine interaction

    NASA Astrophysics Data System (ADS)

    Wu, Yue; Tong, Qingjun; Liu, Gui-Bin; Yu, Hongyi; Yao, Wang

    2016-01-01

    We investigate the optical control possibilities of spin-valley qubit carried by single electrons localized in nanostructures of monolayer TMDs, including small quantum dots formed by lateral heterojunction and charged impurities. The quantum controls are discussed when the confinement induces valley hybridization and when the valley hybridization is absent. We show that the bulk valley and spin optical selection rules can be inherited in different forms in the two scenarios, both of which allow the definition of spin-valley qubit with desired optical controllability. We also investigate nuclear spin-induced decoherence and quantum control of electron-nuclear spin entanglement via intervalley terms of the hyperfine interaction. Optically controlled two-qubit operations in a single quantum dot are discussed.

  6. High-Fidelity Quantum Logic Gates Using Trapped-Ion Hyperfine Qubits.

    PubMed

    Ballance, C J; Harty, T P; Linke, N M; Sepiol, M A; Lucas, D M

    2016-08-01

    We demonstrate laser-driven two-qubit and single-qubit logic gates with respective fidelities 99.9(1)% and 99.9934(3)%, significantly above the ≈99% minimum threshold level required for fault-tolerant quantum computation, using qubits stored in hyperfine ground states of calcium-43 ions held in a room-temperature trap. We study the speed-fidelity trade-off for the two-qubit gate, for gate times between 3.8  μs and 520  μs, and develop a theoretical error model which is consistent with the data and which allows us to identify the principal technical sources of infidelity. PMID:27541450

  7. Anisotropic contributions to the transferred hyperfine field studied using a field-induced spin-reorientation

    NASA Astrophysics Data System (ADS)

    Perry, Laura K.; Ryan, D. H.; Venturini, G.

    We report here a comparison between a field-driven spin-flop (TbMn6 Sn5.46In0.54) and a temperature-driven spin reorientation (TbMn6Sn6-x Gax) in order to demonstrate that the anisotropic contribution to Bhf at the Sn sites can be obtained through the moment reorientation and is independent of the driving force. We show that a complete 90° spin reorientation can be achieved at 300 K in an applied field of 0.57(3) T and that the changes in hyperfine field due to the anisotropic contribution exceed 45% at one of the Sn sites. Quantitative values for the anisotropic constant at the three Sn sites are obtained.

  8. Hyperfine splitting and the Zeeman effect in holographic heavy-light mesons

    NASA Astrophysics Data System (ADS)

    Herzog, Christopher P.; Stricker, Stefan A.; Vuorinen, Aleksi

    2010-08-01

    We inspect the mass spectrum of heavy-light mesons in deformed N=2 super Yang-Mills theory using the AdS/CFT correspondence. We demonstrate how some of the degeneracies of the supersymmetric meson spectrum can be removed upon breaking the supersymmetry, thus leading to the emergence of a hyperfine structure. The explicit SUSY breaking scenarios we consider involve on the one hand, tilting one of the two fundamental D7-branes inside the internal R6 space, and on the other hand, applying an external magnetic field on the (untilted) branes. The latter scenario leads to the well-known Zeeman effect, which we inspect for both weak and strong magnetic fields.

  9. Fine, hyperfine and Zeeman structures of levels of 123Sb I

    NASA Astrophysics Data System (ADS)

    Sobolewski, Łukasz M.; Bouazza, Safa; Kwela, Jerzy

    2016-01-01

    The hyperfine and Zeeman structures of 14 lines of isotope 123Sb covering the UV-NIR spectral range have been measured. The experimental data have been used in order to reanalyse and revise Sb I energy levels. We named majority of them for the first time since they were previously labelled only by their energy values, without any term designations. In both cases of odd- and even-parity levels we took into consideration up to 7 interacting configurations; the set of fine structure parameters and the leading eigenvector percentages of levels as well as their calculated Landé-factors are given. Semi-empirical hfs parameter values extracted from experimental data were compared with ab initio results computed by the use of Cowan code.

  10. Precise measurements of hyperfine components in the spectrum of molecular iodine

    SciTech Connect

    Sansonetti, C.J.

    1996-05-01

    Absolute wave numbers with a typical uncertainty of 1 MHz (95% confidence) were measured for 102 hyperfine-structure components of {sup 127}I{sub 2}. The data cover the range 560-656 nm, with no gaps over 50 cm{sup -1}. The spectra were observed using Doppler-free frequency modulation spectroscopy with tunable cw laser. The laser was locked to selected iodine components and its wave number measured with a high precision Fabry-Perot wavemeter. Accuracy is confirmed by good agreement of 9 of the lines with previous results from other laboratories. These measurements provide a well-distributed set of precise reference lines for this spectral region.

  11. Hyperfine Anomalies in Fr: Boundaries of the Spherical Single Particle Model

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Tandecki, M.; Collister, R.; Aubin, S.; Behr, J. A.; Gomez, E.; Gwinner, G.; Orozco, L. A.; Pearson, M. R.; Sprouse, G. D.; FrPNC Collaboration

    2015-07-01

    We have measured the hyperfine splitting of the 7 P1 /2 state at the 100 ppm level in Fr isotopes (206g,206m,207,209,213,221Fr) near the closed neutron shell (N =126 in 213Fr). The measurements in five isotopes and a nuclear isomeric state of francium, combined with previous determinations of the 7 S1 /2 splittings, reveal the spatial distribution of the nuclear magnetization, i.e., the Bohr-Weisskopf effect. We compare our results with a simple shell model consisting of unpaired single valence nucleons orbiting a spherical nucleus, and find good agreement over a range of neutron-deficient isotopes (207-213Fr). Also, we find near-constant proton anomalies for several even-N isotopes. This identifies a set of Fr isotopes whose nuclear structure can be understood well enough for the extraction of weak interaction parameters from parity nonconservation studies.

  12. Calculation of Radiative Corrections to Hyperfine Splitting in p3/2 States

    SciTech Connect

    Sapirstein, J; Cheng, K T

    2008-07-15

    A recent calculation of the one-loop radiative correction to hyperfine splitting (hfs) of p{sub 1/2} states that includes binding corrections to all orders is extended to p{sub 3/2} states. Nuclear structure plays an essentially negligible role for such states, which is highly advantageous, as difficulties in controlling the Bohr-Weisskopf effect complicate the isolation of QED contributions for both s{sub 1/2} and p{sub 1/2} states. Three cases are studied. We first treat the hydrogen isoelectronic sequence, which is completely nonperturbative in Z{alpha} for high Z. Secondly the lowest lying p{sub 3/2} states of the neutral alkalis are treated, and finally lithium-like bismuth, where extensive theoretical and experimental studies of the hfs of 2s and 2p{sub 1/2} states have been made, is addressed.

  13. Hyperfine Anomalies in Fr: Boundaries of the Spherical Single Particle Model.

    PubMed

    Zhang, J; Tandecki, M; Collister, R; Aubin, S; Behr, J A; Gomez, E; Gwinner, G; Orozco, L A; Pearson, M R; Sprouse, G D

    2015-07-24

    We have measured the hyperfine splitting of the 7P_{1/2} state at the 100 ppm level in Fr isotopes (^{206g,206m,207,209,213,221}Fr) near the closed neutron shell (N=126 in ^{213}Fr). The measurements in five isotopes and a nuclear isomeric state of francium, combined with previous determinations of the 7S_{1/2} splittings, reveal the spatial distribution of the nuclear magnetization, i.e., the Bohr-Weisskopf effect. We compare our results with a simple shell model consisting of unpaired single valence nucleons orbiting a spherical nucleus, and find good agreement over a range of neutron-deficient isotopes (^{207-213}Fr). Also, we find near-constant proton anomalies for several even-N isotopes. This identifies a set of Fr isotopes whose nuclear structure can be understood well enough for the extraction of weak interaction parameters from parity nonconservation studies. PMID:26252677

  14. Anomalous magnetic behaviour of zinc and chromium ferrites without any hyperfine splitting

    NASA Astrophysics Data System (ADS)

    Pandey, B.; Verma, H. C.

    2008-04-01

    Two groups of ferrite namely zinc ferrite and chromium ferrite were synthesized by citrate precursor route in the size range of 8 to 35 nm. We have studied the structural and magnetic behaviour of these ferrites using X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and Mössbauer spectroscopic techniques. Our studies show that the nanocrystalline ferrites interact with the hand magnet strongly and give large magnetization in the VSM measurement. The maximum magnetization in the samples sensitively depends on the particle size of synthesized ferrites. We observed as large as 28 Am2/kg of magnetization in the zinc ferrite nanoparticles while that in chromium ferrite is around 11 Am2/kg. In spite of the large magnetization in the zinc ferrite nanoparticles we did not observe any hyperfine splitting even down to 12 K of temperature. Similar behaviour is also observed for chromium ferrite down to 16 K.

  15. Relativistic many-body investigation of hyperfine interactions in excited S states of alkali metals: Francium and potassium

    SciTech Connect

    Owusu, A.; Dougherty, R.W.; Gowri, G.; Das, T.P.; Andriessen, J.

    1997-07-01

    To enhance the current understanding of mechanisms contributing to magnetic hyperfine interactions in excited states of atomic systems, in particular, alkali-metal atom systems, the hyperfine fields in the excited 5{sup 2}S{sub 1/2}{endash}8{sup 2}S{sub 1/2} states of potassium and 8{sup 2}S{sub 1/2}{endash}12{sup 2}S{sub 1/2} states of francium atoms have been studied using the relativistic linked-cluster many-body perturbation procedure. The net theoretical values of the hyperfine fields for the excited states studied are in excellent agreement with available experimental data for both atoms. There is a significant decrease in importance of the correlation contribution in going from the ground state to the excited states, the correlation contributions as ratios of the direct contribution decreasing rapidly as one moves to the higher excited states. However, the contribution from the exchange core polarization (ECP) effect is nearly a constant fraction of the direct effect for all the excited states considered. Physical explanations are offered for the observed trends in the contributions from the different mechanisms. A comparison is made of the different contributing effects to the hyperfine fields in potassium and francium to those in the related system, rubidium, studied earlier. Extrapolating from our results to the highly excited states of alkali-metal atoms, referred to as the Rydberg states, it is concluded that in addition to the direct contribution from the excited valence electron to the hyperfine fields, a significant contribution is expected from the ECP effect arising from the influence of exchange interactions between electrons in the valence and core states. {copyright} {ital 1997} {ital The American Physical Society}

  16. Hyperfine Interactions of Narrow-line Trityl Radical with Solvent Molecules

    PubMed Central

    Trukhan, S.N.; Yudanov, V.F.; Tormyshev, V.M.; Rogozhnikova, O.Yu.; Trukhin, D.V.; Bowman, M.K.; Krzyaniak, M.D.; Chen, H.; Martyanov, O.N.

    2013-01-01

    The electron nuclear dipolar interactions responsible for some dynamic nuclear polarization (DNP) mechanisms also are responsible for the presence formally in CW EPR spectra of forbidden satellite lines in which both the electron spin and a nuclear spin flip. Such lines arising from 1H nuclei are easily resolved in CW EPR measurements of trityl radicals, a popular family of DNP reagents. The satellite lines overlap some of the hyperfine features from 13C in natural abundance in the trityl radical, but their intensity can be easily determined by simple simulations of the EPR spectra using the hyperfine parameters of the trityl radical. Isotopic substitution of 2H for 1H among the hydrogens of the trityl radical and/or the solvent allows the dipolar interactions from the 1H on the trityl radical and from the solvent to be determined. The intensity of the dipolar interactions, integrated over all the 1H in the system, is characterized by the traditional parameter called reff. For the so-called Finland trityl in methanol, the reff values indicate that collectively the 1H in the unlabeled solvent have a stronger integrated dipolar interaction with the unpaired electron spin of the Finland trityl than do the 1H in the radical and consequently will be a more important DNP route. Although reff has the dimensions of distance, it does not correspond to any simple physical dimension in the trityl radical because the details of the unpaired electron spin distribution and the hydrogen distribution are important in the case of trityls. PMID:23722184

  17. Absence of the hyperfine magnetic field at the Ru site in ferromagnetic rare-earth intermetallics

    NASA Astrophysics Data System (ADS)

    Coffey, D.; Demarco, M.; Ho, P. C.; Maple, M. B.; Sayles, T.; Lynn, J. W.; Huang, Q.; Toorongian, S.; Haka, M.

    2010-05-01

    The Mössbauer effect (ME) is frequently used to investigate magnetically ordered systems. One usually assumes that the magnetic order induces a hyperfine magnetic field, Bhyperfine , at the ME active site. This is the case in the ruthenates, where the temperature dependence of Bhyperfine at R99u sites tracks the temperature dependence of the ferromagnetic or antiferromagnetic order. However this does not happen in the rare-earth intermetallics, GdRu2 and HoRu2 . Specific heat, magnetization, magnetic susceptibility, Mössbauer effect, and neutron diffraction have been used to study the nature of the magnetic order in these materials. Both materials are found to order ferromagnetically at 83.1 and 15.3 K, respectively. Despite the ferromagnetic order of the rare-earth moments in both systems, there is no evidence of a correspondingly large Bhyperfine in the Mössbauer spectrum at the Ru site. Instead the measured spectra consist of a narrow peak at all temperatures which points to the absence of magnetic order. To understand the surprising absence of a transferred hyperfine magnetic field, we carried out ab initio calculations which show that spin polarization is present only on the rare-earth site. The electron spin at the Ru sites is effectively unpolarized and, as a result, Bhyperfine is very small at those sites. This occurs because the 4d Ru electrons form broad conduction bands rather than localized moments. These 4d conduction bands are polarized in the region of the Fermi energy and mediate the interaction between the localized rare-earth moments.

  18. Effect of nanocrystallization on the electrical conductivity enhancement and Moessbauer hyperfine parameters of iron based glasses

    SciTech Connect

    El-Desoky, M.M.; Ibrahim, F.A.; Mostafa, A.G.; Hassaan, M.Y.

    2010-09-15

    Selected glasses of Fe{sub 2}O{sub 3}-PbO{sub 2}-Bi{sub 2}O{sub 3} system have been transformed into nanomaterials by annealing at temperature close to crystallization temperature (T{sub c}) for 1 h. The effects of the annealing of the present samples on its structural and electrical properties were studied by Moessbauer spectroscopy, transmission electron micrograph (TEM), differential scanning calorimeter (DSC) and dc conductivity ({sigma}). Moessbauer spectroscopy was used in order to determine the states of iron and its hyperfine structure. The effect of nanocrystalization on the Moessbauer hyperfine parameters did not exhibit significant modifications in present glasses. However, in case of glass ceramic nanocrystals show a distinct decrease in the quadrupole splitting ({Delta}) is observed, reflecting an evident decrease in the distortion of structural units like FeO{sub 4} units. In general, the Moessbauer parameters of the nano-crystalline phase exhibit tendency to increase with PbO{sub 2} content. TEM of as-quenched glasses confirm the homogeneous and essentially featureless morphology. TEM of the corresponding glass ceramic nanocrystals indicates nanocrystals embedded in the glassy matrix with average particle size of about 32 nm. The crystallization temperature (T{sub c}) was observed to decrease with PbO{sub 2} content. The glass ceramic nanocrystals obtained by annealing at T{sub c} exhibit improvement of electrical conductivity up to four orders of magnitude than the starting glasses. This considerable improvement of electrical conductivity after nanocrystallization is attributed to formation of defective, well-conducting phases 'easy conduction paths' along the glass-crystallites interfaces.

  19. Hyperfine Interactions in the Heavy-Fermion Superconductor UBe13: 9Be NMR Studies

    NASA Astrophysics Data System (ADS)

    Tou, Hideki; Tsugawa, Norihiko; Sera, Masafumi; Harima, Hisatomo; Haga, Yoshinori; Ōnuki, Yoshichika

    2007-02-01

    9Be NMR measurements have been performed for a single crystal UBe13 with Tc≈ 0.86 K. For an applied field parallel to [001] direction, we observed a well-split 9Be NMR line with the sharp line-width of ≈10 Oe, guaranteeing the high-quality of the single crystal from the microscopic viewpoint. We also calculated the electric field gradient (9EFG) tensor at Be(II) site using the band-structure calculation based on an FLAPW-LDA method. From the field-angle dependence of 9Be-NMR spectra together with the result of the band-structure calculation, we identified the 9EFG and 9Be Knight shift tensors. The Knight shift of UBe13 is enhanced by a factor of hundreds compared to that of a pure Be metal, suggesting the local spin density at Be 2s and 2 p orbitals is enhanced through the hybridization with 5 f electrons. The isotropic and anisotropic hyperfine fields are obtained as Aiso≈ 436 Oe/μB, (As1,As2,As3)≈(192,44,-236) Oe/μB. The anisotropic part can be explained by the spin-dipolar field attributed to the local-spin-density at Be 2 p orbital, and the 2 p orbital perpendicular to the mirror plane [for example 2 px for Be(IIA)] contributes mainly to the conduction band. On the other hand, the isotropic part mainly originates from the core polarization hyperfine field of the Be s shell due to the unpaired Be 2 p electrons. The present results give direct evidence that the Be 2 p orbital is responsible for conduction bands.

  20. Electrical properties and hyperfine interactions of boron doped Fe3O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Amir, Md; Ünal, B.; Geleri, M.; Güngüneş, H.; Shirsath, Sagar E.; Baykal, A.

    2015-12-01

    The single spinel phase nano-structured particles of FeBxFe2-xO4 (x = 0.1, 0.2, 0.3, 0.4 and 0.5) were synthesized by the glycothermal method and the effect of B3+ substitution on structural and dielectric properties of Fe3O4 were studied. From 57Fe Mössbauer spectroscopy data, the variation in line width, isomer shift, quadrupole splitting and hyperfine magnetic field values on B3+ substitution have been determined. The hyperfine field values at B- and A-sites gradually decrease with increasing B3+ ion concentration (x). The cation distributions obtained from Bertaut method are in line with Mössbauer results. Complex impedance analysis of boron-substituted spinel ferrites have been made extensively in order to investigate the significant changes in ac and dc conductivity as well as complex permittivity when the boron composition ratio varies from 0.1 to 0.5. It is found that both ac and dc conductivity are also dependent on the boron content in addition to both temperature and applied frequency. The dc conductivity tendency does not purely obey the Arrhenius plots. The dielectric constant and loss of complex permittivity, in general, show similar attitudes as seen in some nanocomposites containing spinel ferrites except for some fluctuations and shifts along the characteristics of the curves. Furthermore, their imaginary components of both permittivity and modulus are almost found to obey the power law with any exponent values varying between 0.5 and 2 in accordance with the level of boron concentrations.

  1. Towards a precise measurement of the antihydrogen ground state hyperfine splitting in a beam: the case of in-flight radiative decays

    NASA Astrophysics Data System (ADS)

    Lundmark, R.; Malbrunot, C.; Nagata, Y.; Radics, B.; Sauerzopf, C.; Widmann, E.

    2015-09-01

    The ASACUSA antihydrogen setup at the CERN Antiproton Decelerator (AD) consists of an antihydrogen source (cusp magnet coupled to a positron source and an antiproton catching magnet) followed by a spectrometer beamline. After production in the cusp, the antihydrogen atoms decay while they escape the trap leading to changes in their effective magnetic moment which in turn affect their trajectories in the beamline. Those sequential decays in the presence of a varying magnetic field strength from their production point in the cusp to their detection at the end of the spectrometer line can in principle greatly affect the prospects for a precision measurement of the antihydrogen hyperfine splitting given the so-far relatively low number of available anti-atoms. The impact of the antihydrogen decay in this context has for the first time been simulated. The implementation of atomic radiative decay has been done in Geant4 to extend the particle tracking capabilities originally embedded in Geant4 to excited atoms, and to allow studies of the effect of dynamic atomic properties on trajectories. This new tool thus allows the study of particle-matter interaction via the Geant4 toolkit while properly taking into account the atomic nature of the object under study. The implementation as well as impacts on the experimental sensitivity for antihydrogen spectroscopy are discussed in this paper.

  2. Hyperfine structure interval of the 2s state of hydrogenlike atoms and a constraint on a pseudovector boson with mass below 1 keV/c{sup 2}

    SciTech Connect

    Karshenboim, S. G.

    2011-06-15

    A constraint on a spin-dependent interaction, induced by a pseudovector light boson, is presented. The interaction includes a Yukawa-type contribution {alpha}{sup ''}(s{sub 1}{center_dot}s{sub 2})e{sup -{lambda}r}/r and a contact spin-spin term. To disentangle the long-range and contact terms we utilize experimental data on the 1s and 2s hyperfine intervals for light two-body atoms and construct a specific difference 8xE{sub hfs}(2s)-E{sub hfs}(1s). That allows one to constrain the spin-dependent coupling constant {alpha}{sup ''} of an electron-nucleus Yukawa-type interaction in hydrogen, deuterium, and the helium-3 ion at the level below a part in 10{sup 16}. The derived constraint is related to the range of masses below 4 keV/c{sup 2}. The combined constraint including the contact terms is also presented.

  3. Heterogeneous and hyperfine interactions between valence states of molecular iodine correlating with the I(2P1/2) + I(2P1/2) dissociation limit

    NASA Astrophysics Data System (ADS)

    Baturo, Vera V.; Cherepanov, Igor N.; Lukashov, Sergey S.; Poretsky, Sergey A.; Pravilov, Anatoly M.; Zhironkin, Anatoly I.

    2016-05-01

    Detailed analysis of interactions between all 0g + , 1u, and 0u - weakly bound states of iodine molecule correlating with the I(2P1/2) + I(2P1/2) (bb) dissociation limit has been performed. For this purpose, the 0u - (bb) state has been described using analysis of rotationally resolved excitation spectra of luminescence from the g 0g - state populated in a three-step three-color perturbation facilitated excitation scheme via the 0u - state. Energies of 41 rovibrational levels, molecular constants, and potential energy curve have been determined. Energy gaps between closest rovibrational levels of the 0u - and 0g + , 1u (bb) states are found to be large, ˜6 cm-1. However, interaction of all three 0g + , 1u, and 0u - (bb) states has been observed. It has been found that the 0u - and 1u electronic states are mixed by heterogeneous interactions, while their mixing with the 0g + one is due to hyperfine interactions predominantly. Admixture coefficients and electronic matrix elements of the coupling between the 0g + ˜1u, 0g + ˜ 0u - , and 0u - ˜1u states have been estimated.

  4. Hyperfine structure in 229gTh3+ as a probe of the 229gTh→ 229mTh nuclear excitation energy.

    PubMed

    Beloy, K

    2014-02-14

    We identify a potential means to extract the 229gTh→ 229mTh nuclear excitation energy from precision microwave spectroscopy of the 5F(5/2,7/2) hyperfine manifolds in the ion 229gTh3+. The hyperfine interaction mixes this ground fine structure doublet with states of the nuclear isomer, introducing small but observable shifts to the hyperfine sublevels. We demonstrate how accurate atomic structure calculations may be combined with the measurement of the hyperfine intervals to quantify the effects of this mixing. Further knowledge of the magnetic dipole decay rate of the isomer, as recently reported, allows an indirect determination of the nuclear excitation energy. PMID:24580690

  5. Wavelengths, energy levels and hyperfine structure of Mn II and Sc II.

    NASA Astrophysics Data System (ADS)

    Nave, Gillian; Pickering, Juliet C.; Townley-Smith, Keeley I. M.; Hala, .

    2015-08-01

    For many decades, the Atomic Spectroscopy Groups at the National Institute of Standards and Technology (NIST) and Imperial College London (ICL) have measured atomic data of astronomical interest. Our spectrometers include Fourier transform (FT) spectrometers at NIST and ICL covering the region 1350 Å to 5.5 μm and a 10.7-m grating spectrometer at NIST covering wavelengths from 300 - 5000 Å. Sources for these spectra include high-current continuous and pulsed hollow cathode (HCL) lamps, Penning discharges, and sliding spark discharges. Recent work has focused on the measurement and analysis of wavelengths, energy levels, and hyperfine structure (HFS) constants for iron-group elements. The analysis of FT spectra of Cr I, Mn I, and Mn II is being led by ICL and is described in a companion poster [1]. Current work being led by NIST includes the analysis of HFS in Mn II, analysis of Mn II in the vacuum ultraviolet, and a comprehensive analysis of Sc II.Comprehensive HFS constants for Mn II are needed for the interpretation of stellar spectra and incorrect abundances may be obtained when HFS is omitted. Holt et al. [2] have measured HFS constants for 59 levels of Mn II using laser spectroscopy. We used FT spectra of Mn/Ni and Mn/Cu HCLs covering wavelength ranges from 1350 Å to 5.4 μm to confirm 26 of the A constants of Holt et al. and obtain values for roughly 40 additional levels. We aim to obtain HFS constants for the majority of lines showing significant HFS that are observed in chemically-peculiar stars.Spectra of Sc HCLs have been recorded from 1800 - 6700 Å using a vacuum ultraviolet FT spectrometer at NIST. Additional measurements to cover wavelengths above 6700 Å and below 1800 Å are in progress. The spectra are being analyzed by NIST and Alighar Muslim University, India in order to derive improved wavelengths, energy levels, and hyperfine structure parameters.This work was partially supported by NASA, the STFC and PPARC (UK), the Royal Society of the UK

  6. Polarized {sup 3}He{sup −} ion source with hyperfine state selection

    SciTech Connect

    Dudnikov, V.; Morozov, V.; Dudnikov, A.

    2015-04-08

    High beam polarization is essential to the scientific productivity of a collider. Polarized {sup 3}He ions are an essential part of the nuclear physics programs at existing and future ion-ion and electron-ion colliders such as BNL's RHIC and eRHIC and JLab's ELIC. Ion sources with performance exceeding that achieved today are a key requirement for the development of these next generation high-luminosity high-polarization colliders. The development of high-intensity high-brightness arc-discharge ion sources at the Budker Institute of Nuclear Physics (BINP) has opened up an opportunity for realization of a new type of a polarized {sup 3}He{sup −} ion source. This report discusses a polarized {sup 3}He{sup −} ion source based on the large difference of extra-electron auto-detachment lifetimes of the different {sup 3}He{sup −} ion hyperfine states. The highest momentum state of 5/2 has the largest lifetime of τ ∼ 350 µs while the lower momentum states have lifetimes of τ ~ 10 µs. By producing {sup 3}He{sup −} ion beam composed of only the |5/2, ±5/2> hyperfine states and then quenching one of the states by an RF resonant field, {sup 3}He{sup −} beam polarization of 90% can be achieved. Such a method of polarized {sup 3}He{sup −} production has been considered before; however, due to low intensities of the He{sup +} ion sources existing at that time, it was not possible to produce any interesting intensity of polarized {sup 3}He{sup −} ions. The high-brightness arc-discharge ion source developed at BINP can produce a high-brightness {sup 3}He{sup +} beam with an intensity of up to 2 A allowing for selection of up to ∼1-4 mA of {sup 3}He{sup −} ions with ∼90% polarization. The high gas efficiency of an arc-discharge source is important due to the high cost of {sup 3}He gas. Some features of such a PIS as well as prototype designs are considered. An integrated {sup 3}He{sup −} ion source design providing high beam polarization could be

  7. Ab initio study of hyperfine interaction parameters in C14 Hf and Zr Laves-phase compounds

    NASA Astrophysics Data System (ADS)

    Belošević-Čavor, Jelena; Koteski, V.; Radaković, J.; Cekić, B.

    2009-05-01

    Using ab initio density-functional theory approach the electric field gradients (EFGs) and hyperfine magnetic fields (HMFs) for the isostructural C14 Laves-phase compounds HfCr2 , HfFe2 , HfMn2 , ZrCr2 , and ZrMn2 are calculated and compared with the available experimental data from time differential perturbed angular-correlation (TDPAC) spectroscopy. In addition, supercell calculations of the hyperfine interaction parameters at the nucleus of the substitutional Ta impurity are used to elucidate the role played by the Ta probe in the TDPAC measurements of Hf and Zr C14 Laves phases and solve the controversy related to the origin of the HMF in the C14 HfFe2 compound.

  8. Determination of molecular hyperfine-structure constant using the second-order relativistic many-body perturbation theory

    SciTech Connect

    Nayak, Malaya K.; Chaudhuri, Rajat K.

    2011-02-15

    The spin-rotational Hamiltonian parameters A{sub ||} and A{sub perpendicular} for the BaF molecule are calculated using four-component relativistic spinors at the second-order many-body perturbation theory (MBPT) level via the Z-vector technique. The second-order MBPT is applied to assess the accuracy of the computed hyperfine-structure constants before studying the problem with the state-of-the-artcoupled cluster with single and double excitations (CCSD) method which is highly accurate but computationally more expensive than MBPT. The hyperfine-structure constants A and A{sub d} resulted from these calculations agree favorably well with experimental findings and with other correlated calculations. The convergence behavior of A and A{sub d} with respect to the number of active orbitals used in the perturbative calculations suggests that our estimated A and A{sub d} values should be accurate.

  9. Observation of hyperfine structure of D022-Mn3‑ x Fe x Ga by Mössbauer effect

    NASA Astrophysics Data System (ADS)

    Koeba, Akira; Shima, Toshiyuki; Doi, Masaaki

    2016-07-01

    In this work, to obtain the design guideline for a magnet made of a Mn-based alloy, Mn3‑ x Fe x Ga alloys were prepared by arc melting and the magnetic state of Fe in the alloys and hyperfine structure were investigated on the basis of the Mössbauer effect. As a result, D022-Mn2.2Fe0.5Ga alloys were obtained by annealing at 350 °C for 2 days. From the Mössbauer spectrum of Mn2.2Fe0.5Ga, it was clear that Fe replaced Mn in the Mn II site of the D022 structure. In addition, it was also found that the hyperfine field of Fe is extremely lower in the Mn II site than in the Mn I site.

  10. DFT study of the hyperfine parameters and magnetic properties of ZnO doped with 57Fe

    NASA Astrophysics Data System (ADS)

    Abreu, Y.; Cruz, C. M.; Piñera, I.; Leyva, A.; Cabal, A. E.; Van Espen, P.

    2014-05-01

    Magnetic state of 57Fe implanted and doped ZnO samples have been reported and studied by Mössbauer spectroscopy at different temperatures. The Mössbauer spectra mainly showed four doublets and three sextets, but some ambiguous identification remains regarding the probe site location and influence of defects in the hyperfine and magnetic parameters. In the present work some possible implantation configurations are suggested and evaluated using Monte Carlo simulation and electronic structure calculations within the density functional theory. Various implantation environments were proposed and studied considering the presence of defects. The obtained 57Fe hyperfine parameters show a good agreement with the reported experimental values for some of these configurations. The possibility of Fe pair formation, as well as a Zn site vacancy stabilization between the second and third neighborhood of the implantation site, is supported.

  11. Hyperfine structure effects in Doppler-broadening thermometry on water vapor at 1.4 μm

    NASA Astrophysics Data System (ADS)

    Domenica De Vizia, Maria; Odintsova, Tatyana; Gianfrani, Livio

    2016-04-01

    This article builds upon a previous work dealing with the budget of uncertainties associated to our recent determination of the Boltzmann constant by means of Doppler broadening thermometry. We report on the outcomes of theoretical calculations and numerical simulations aimed to precisely quantify the influence of the unresolved hyperfine structure of a given ortho component of the \\text{H}218 O spectrum at 1.4 μm on the measurement of the Doppler width of the line itself. We have found that, if the hyperfine structure of the {{4}4,1}\\to {{4}4,0} line of the {ν1}+{ν3} band was ignored, the spectroscopic measurement of the Boltzmann constant would be affected by a relative systematical deviation of 4\\cdot {{10}-8} .

  12. Sub-Doppler direct infrared laser absorption spectroscopy in fast ion beams: The fluorine hyperfine structure of HF +

    NASA Astrophysics Data System (ADS)

    Coe, J. V.; Owrutsky, J. C.; Keim, E. R.; Agman, N. V.; Hovde, D. C.; Saykally, R. J.

    1989-04-01

    We report the development of a new general technique for measuring vibration-rotation spectra of molecular ions with sub-Doppler resolution and with accurate determination of the mass and number density of the carriers of all spectral features. With this method, called direct laser absorption spectroscopy in fast ion beams (DLASFIB), we have carried out the first observation of direct absorption of photons by ions in a fast ion beam. Hyperfine-resolved vibration-rotation transitions of HF+ have been measured, and along with optical combination differences and laser magnetic resonance data, have been analyzed to yield the fluorine hyperfine parameters a, b, c and d for both v=0 and v=1 in the X 2Π state. Comparisons with many-body perturbation theory results are presented.

  13. Local hyperfine field vector of positive muon in mono-domain single crystal of antiferromagnetic La2CuO4

    NASA Astrophysics Data System (ADS)

    Torikai, E.; Ishihara, H.; Nagamine, K.; Kitazawa, H.; Tanaka, I.; Kojima, H.; Sulaiman, S. B.; Srinivas, S.; Das, T. P.

    1993-03-01

    By using a monodomain single crystal La2CuO4 grown by the travelling solvent floating zone method, the strength and direction of the local hyperfine field vector at positive muon sites were determined. Combining with the μ+ location determined separately, we found the importance of the local hyperfine field contributions with dipolar symmetry as well as the distant dipolar field from surrounding point dipoles of Cu atomic moments.

  14. Does the temperature dependence at constant volume of the hyperfine field of heavy impurities in ferromagnetic metals depend explicitly upon the amplitude of lattice vibrations?

    NASA Astrophysics Data System (ADS)

    Riedi, P. C.; Webber, G. D.

    1983-12-01

    Lattice dynamics seem to have little effect on the temperature dependence of the hyperfine field of pure iron and nickel and of most impurities in these metals but it is shown that Au in iron may be an exception to this rule. The hyperfine fields of other heavy impurities ( FeRu, FeIr, NiPt) were found to have a normal temperature dependence.

  15. Hyperfine structures and Landé gJ-factors for n=2 states in beryllium-, boron-, carbon-, and nitrogen-like ions from relativistic configuration interaction calculations

    NASA Astrophysics Data System (ADS)

    Verdebout, S.; Nazé, C.; Jönsson, P.; Rynkun, P.; Godefroid, M.; Gaigalas, G.

    2014-09-01

    Energy levels, hyperfine interaction constants, and Landé gJ-factors are reported for n=2 states in beryllium-, boron-, carbon-, and nitrogen-like ions from relativistic configuration interaction calculations. Valence, core-valence, and core-core correlation effects are taken into account through single and double-excitations from multireference expansions to increasing sets of active orbitals. A systematic comparison of the calculated hyperfine interaction constants is made with values from the available literature.

  16. Constituent quark masses obtained from hadron masses with contributions of Fermi-Breit and Glozman-Riska hyperfine interactions

    SciTech Connect

    Borka Jovanovic, V.; Borka, D.; Ignjatovic, S. R.; Jovanovic, P.

    2010-12-01

    We use the color-spin and flavor-spin interaction Hamiltonians with SU(3) flavor symmetry breaking to obtain meson and baryon mass formulas. Adjusting these masses with experimental masses we determine the constituent quark masses. We discuss the constituent quark masses obtained from meson and baryon mass fits. The results for constituent quark masses are very similar in the case of two different phenomenological models: Fermi-Breit and Glozman-Riska hyperfine interactions.

  17. Single chirped pulse control of hyperfine states population in Rb atom in the framework of the four-level system

    NASA Astrophysics Data System (ADS)

    Zakharov, Vladislav; Malinovskaya, Svetlana

    2012-06-01

    Electron population dynamics within the hyperfine structure in the Rb atom induced by a single ns pulse is theoretically investigated. The aim is to develop a methodology of the implementation of linearly chirped laser pulses for the desired excitations in the Rb atoms resulting in the creation of predetermined non-equilibrium states. A semi-classical model of laser pulse interaction with a four-level system representing the hyperfine energy levels of the Rb atom involved into dynamics has been developed. The equations for the probability amplitudes were obtained from the Schrodinger equation with the Hamiltonian that described the time evolution of the population of the four states in the field interaction representation. A code was written in Fortran for a numerical analysis of the time evolution of probability amplitudes as a function of the field parameters. The dependence of the quantum yield on the pulse duration, the linear chirp parameter and the Rabi frequency was studied to reveal the conditions for the entire population transfer to the upper hyperfine state of the 5S1/2 electronic level. The results may provide a robust tool for quantum operations in the alkali atoms.

  18. Construction of the energy matrix for complex atoms. Part V: Electrostatically correlated spin-orbit and electrostatically correlated hyperfine interactions

    NASA Astrophysics Data System (ADS)

    Elantkowska, Magdalena; Ruczkowski, Jarosław; Dembczyński, Jerzy

    2016-02-01

    The continuation of the previous series of papers related to the construction of the energy matrix for complex atoms is presented. The contributions from the second-order perturbation theory concerning electrostatically correlated spin-orbit interactions (CSO), as well as electrostatically correlated hyperfine interactions (CHFS) to the atomic structure of nlN, nlNn1l1^{N_1} and nlNn1l1^{N_1}n2l2^{N_2} configurations, are considered. This theory assumes that the electron excitation n0l0→ nl affects spin-orbit splitting and magnetic dipole and electric quadrupole hyperfine structure in the same way which will be discussed below. Part I of the series presented, in general terms, a method allowing the analysis of complex electronic systems. Parts II, III and IV provided a description of an electrostatic interaction up to second-order perturbation theory; they constitute the basis for the design of an efficient computer program package for large-scale calculations of accurate wave functions. Analyses presented in the entire series of our papers clearly demonstrate that obtaining the precise wave functions is impossible without considering the contribution from the second-order effects into fine and hyperfine atomic structure.

  19. Theory of hyperfine interactions in potassium and Sc2+sion:Trends in systems isoelectronic with potassium

    NASA Astrophysics Data System (ADS)

    Owusu, Alfred; Yuan, Xing; Panigrahy, S. N.; Dougherty, R. W.; Das, T. P.; Andriessen, J.

    1997-04-01

    A first-principles relativistic many-body investigation of magnetic hyperfine fields has been carried out for the ground states 4 2 S1/2 of the alkali atom K and doubly charged ion Sc2+ completing the investigation over the three members of the isoelectronic series K, Ca+ , and Sc2+ with a single valence electron in the 4s state, since Ca+ had been investigated by us previously. This allows one to study both the nature of agreement with experiment over this series as the charge increases and the trends in the contributions from the major mechanisms responsible for the hyperfine fields in these systems. The calculated magnetic hyperfine fields in tesla for K, Ca+ , and Sc2+ are 56.81, 135.90, and 239.29, respectively. These agree very well with the measured values of 58.02 T for K and 140.30 T for Ca+ . No experimental data are available for the Sc2+ system. The exchange core polarization (ECP) and correlation contributions, as fractions of the valence contribution, are found to decrease rapidly as one goes to systems with higher ionic charges, the decrease being more drastic for correlation effects. The trend of the ratios of ECP and correlation contributions to the valence contribution for both K and Sc2+ were compared with those calculated for the neighboring alkali-metal systems, sodium and rubidium. The physical explanations for the results and the observed trends in the contributions from the different mechanisms are discussed.

  20. High precision measurements of hyperfine structure in Tm II, N/sub 2//sup +/ and Sc II

    SciTech Connect

    Mansour, N.B.; Dinneen, T.P.; Young, L.

    1988-01-01

    We have applied the technique of collinear fast-ion-beam laser spectroscopy to measure the hyperfine structure (hfs) in Sc II, Tm II and N/sub 2//sup +/. Laser induced fluorescence was observed from a 50 keV ion beam which was superimposed with the output of an actively stabilized ring dye laser (rms bandwidth <1 MHz). Hyperfine measurements were made in the metastable 3d/sup 2/ and the excited 3d4p configuration of Sc II and in the 4f/sup 13/6s and 4f/sup 13/5d configurations of the Tm II. The fine and hyperfine structure of N/sub 2//sup +/ has been observed in the (0,1) and (1,2) band of B/sup 2/..sigma../sub u//sup +//minus/X/sup 2/..sigma../sub g//sup +/ system. Higher resolution measurements of the metastable 3d/sup 2/ configuration in Sc II were also made by laser-rf double resonance. The experimental results will be compared with those obtained by multiconfiguration Hartree-Fock ab-initio calculations. 15 refs., 4 figs., 5 tabs.

  1. Singlet-to-triplet interconversion using hyperfine as well as ferromagnetic fringe fields.

    PubMed

    Wohlgenannt, M; Flatté, M E; Harmon, N J; Wang, F; Kent, A D; Macià, F

    2015-06-28

    Until recently the important role that spin-physics ('spintronics') plays in organic light-emitting devices and photovoltaic cells was not sufficiently recognized. This attitude has begun to change. We review our recent work that shows that spatially rapidly varying local magnetic fields that may be present in the organic layer dramatically affect electronic transport properties and electroluminescence efficiency. Competition between spin-dynamics due to these spatially varying fields and an applied, spatially homogeneous magnetic field leads to large magnetoresistance, even at room temperature where the thermodynamic influences of the resulting nuclear and electronic Zeeman splittings are negligible. Spatially rapidly varying local magnetic fields are naturally present in many organic materials in the form of nuclear hyperfine fields, but we will also review a second method of controlling the electrical conductivity/electroluminescence, using the spatially varying magnetic fringe fields of a magnetically unsaturated ferromagnet. Fringe-field magnetoresistance has a magnitude of several per cent and is hysteretic and anisotropic. This new method of control is sensitive to even remanent magnetic states, leading to different conductivity/electroluminescence values in the absence of an applied field. We briefly review a model based on fringe-field-induced polaron-pair spin-dynamics that successfully describes several key features of the experimental fringe-field magnetoresistance and magnetoelectroluminescence. PMID:25987575

  2. Theoretical Study of ^14N Hyperfine Interactions in NO-Hemoglobin in R and T States

    NASA Astrophysics Data System (ADS)

    Pujari, Minakhi; Sahoo, N.; Das, T. P.

    2002-03-01

    The origin of the change(J. C. W. Chien and L. C. Dickinson, J. Biol. Chem. 252), 1331 (1977); M. Chevion, A. Stern, J. Peisach, W. E. Blumberg and S. Simon, Biochemistry 17, 1745 (1978). in the ^14N hyperfine splitting of Electron Paramagnetic Resonance signals in the R and T states of NO-Hb from a 9-line pattern to a 3-line one has been investigated using the first-principles Hartree-Fock procedure. The influence of various factors have been studied, namely changes from linear configuration for Fe-NO bonding to non-linear, change from a protonated imidazole ligand for the heme group to a deprotonated one, and the increase in length, and consequent weakening, of the Fe-N_ɛ bond associated with the imidazole ligand. The last factor is the only one that is able to explain the change in the EPR signal as found from earlier Extended Hückel studies(S. K. Mun, Jane C. Chang and T. P. Das, Proc. Nat. Acad. Sci. (USA) 76), 4842 (1979)..

  3. Transmission integral analysis of Mössbauer spectra displaying hyperfine parameter distributions with arbitrary profile

    SciTech Connect

    Klencsár, Zoltán

    2014-10-27

    Accurate quantitative analysis of Mössbauer spectra displaying thickness effects requires the consideration of the so-called transmission integral when modeling the spectral shape. Whereas this is straightforward when the correct model for the decomposition of the absorber's nuclear resonance absorption cross-section into individual components is a priori known, in the absence of such knowledge and notably in the presence of hyperfine parameter distributions with an unknown profile, the so-called model-independent evaluation methods could be used to fit the spectra. However, the methods available for this purpose were developed for the analysis of spectra for which the thin absorber approximation is valid, and thus they do not take the sample thickness and related effects into account. Consequently, in order to use them for spectra displaying thickness effects, their usage needs to be generalized by combining them with transmission integral fitting. A new algorithm realizing such a generalized version of the Hesse-Rübartsch model-independent evaluation method was developed recently as an integral part of the MossWinn program. In the present work, the working principle of the newly developed algorithm is described in details along with examples illustrating the capabilities of the method for the case of {sup 57}Fe Mössbauer spectroscopy.

  4. Redox-dependent structure change and hyperfine nuclear magnetic resonance shifts in cytochrome c

    SciTech Connect

    Feng, Yiquing; Roder, H.; Englander, S.W. )

    1990-04-10

    Proton nuclear magnetic resonance assignments for reduced and oxidized equine cytochrome c show that many individual protons exhibit different chemical shifts in the two protein forms, reflecting diamagnetic shift effects due to structure change, and in addition contact and pseudocontact shifts that occur only in the paramagnetic oxidized form. To evaluate the chemical shift differences for structure change, the authors removed the pseudocontact shift contribution by a calculation based on knowledge of the electron spin g tensor. The g-tensor calculation, when repeated using only 12 available C{sub {alpha}}H proton resonances for cytochrom c from tuna, proved to be remarkably stable. The derived g tensor was then used together with spatial coordinates for the oxidized form to calculate the pseudocontact shift contribution to proton resonances at 400 identifiable sites throughout the protein, so that the redox-dependent chemical shift discrepancy, could be evaluated. Large residual changes in chemical shift define the Fermi contact shifts, where are found as expected to be limited to the immediate covalent structure of the heme and its ligands and to be asymmetrically distributed over the heme. The chemical shift discrepancies observed appear in the main to reflect structure-dependent diamagnetic shifts rather than hyperfine effects due to displacements in the pseudocontact shift field. Although 51 protons in 29 different residues exhibit significant chemical shift changes, the general impressions one of small structural adjustments to redox-dependent strain rather than sizeable structural displacements or rearrangements.

  5. Low temperature behavior of hyperfine fields in amorphous and nanocrystalline FeMoCuB

    SciTech Connect

    Kohout, Jaroslav; Křišt'an, Petr; Kubániová, Denisa; Kmječ, Tomáš; Závěta, Karel; Štepánková, Helena; Lančok, Adriana; Sklenka, L'ubomír; Matúš, Peter; and others

    2015-05-07

    Low temperature (4.2 K) magnetic behavior of Fe{sub 76}Mo{sub 8}Cu{sub 1}B{sub 15} metallic glass was studied by {sup 57}Fe Mössbauer spectrometry (MS) and {sup 57}Fe NMR. Distributions of hyperfine magnetic fields P(B) were determined for as-quenched and annealed (nanocrystalline) samples with relative fraction of the grains about 43%. P(B) distributions were derived for both the amorphous matrix and nanocrystalline grains. NMR of alloys with natural and {sup 57}Fe enriched Fe enabled to assess the contribution of {sup 11}B to the total NMR signal. P(B) distribution of the as-quenched alloy derived from MS matches reasonably well the one from NMR of the enriched sample. NMR signal from the sample with natural Fe exhibits contributions from {sup 11}B nuclei. The principal NMR lines of the annealed alloys at 47 MHz correspond to bcc Fe nanocrystals. Small asymmetry of the lines towards higher frequencies might be an indication of possible impurity atoms in the bcc structure. The observed differences between natural and enriched samples are attributed to higher sensitivity in the latter. Positions of the lines attributed to bcc Fe nanocrystals obtained from MS and NMR are in perfect agreement.

  6. Tungsten monocarbide, WC: Pure rotational spectrum and 13C hyperfine interaction

    NASA Astrophysics Data System (ADS)

    Wang, Fang; Steimle, Timothy C.

    2012-01-01

    The J = 1 → 2 pure rotational transitions in the X3Δ1(v = 0) state of 186W12C and 184W12C were recorded using a pump/probe microwave optical double resonance (PPMODR) technique and analyzed to give fine structure parameters. The field-free [17.6]2← X3Δ1 (1, 0) bands of the W13C isotopologues were recorded using laser induced fluorescence and analyzed to produce the 13C(I = 1/2) magnetic hyperfine parameter. Bonding in the [17.6]2(v = 1) and X3Δ1(v = 0) states is discussed and a comparison of the experimentally determined properties of the X3Δ1(v = 0) state with those predicted as a prelude to the electron electric dipole moment (eEDM) measurements [J. Lee, E. R. Meyer, R. Paudel, J. L. Bohn, and A. E. Leanhardt, J. Mod. Opt. 56, 2005 (2009), 10.1080/09500340903349930] is given.

  7. Structural, optical, hyperfine and magnetization studies of ZnO encapsulated α-Fe nanoparticles

    SciTech Connect

    Rathore, A.K.; Pati, S.P.; Roychowdhury, A.; Das, D.

    2014-12-15

    We report the successful preparation and characterization of magnetic-fluorescent nanoparticles (NPs) by overcoming the difficulty of handling α-Fe nanoparticles that are less stable and have high affinity to get oxidized in air even at room temperature. Nanocrystalline α-Fe particles embedded by ZnO have been synthesized by a two step chemical route. Concentration of α-Fe has been varied as 15, 30 and 50 wt% of the sample. Detailed investigations on structural, hyperfine, optical and magnetic characteristics have been carried out. X-ray diffraction, transmission electron microscopy and fourier transform infrared spectroscopy studies have been used to confirm the coexistence of Fe and ZnO phases in the nanocomposites (NCs). The presence of α-Fe is also confirmed by Mössbauer spectroscopy. However, other forms of iron are also detected in the sample. UV–vis spectrum of nanocomposites shows a red shift with respect to the pristine ZnO which is attributed to the electron transfer between Fe and ZnO that provides support to the formation of the Fe- ZnO NC. The photoluminescence (PL) spectra of Fe-ZnO nanocomposites exhibit blue shift of the UV and weaker visible emission lines compared to the pristine ZnO. Nanocomposites are found to be magnetically soft having high saturation magnetization with very low remanence. Low temperature coercivity enhancement due to freezing of uncompensated surface spins is also found in all samples.

  8. Properties of Gd2O3 nanoparticles studied by hyperfine interactions and magnetization measurements

    NASA Astrophysics Data System (ADS)

    Correa, E. L.; Bosch-Santos, B.; Cavalcante, F. H. M.; Correa, B. S.; Freitas, R. S.; Carbonari, A. W.; Potiens, M. P. A.

    2016-05-01

    The magnetic behavior of Gd2O3 nanoparticles, produced by thermal decomposition method and subsequently annealed at different temperatures, was investigated by magnetization measurements and, at an atomic level, by perturbed γ - γ angular correlation (PAC) spectroscopy measuring hyperfine interactions at 111In(111Cd) probe nuclei. Nanoparticle structure, size and shape were characterized by X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). Magnetization measurements were carried out to characterize the paramagnetic behavior of the samples. XRD results show that all samples crystallize in the cubic-C form of the bixbyite structure with space group Ia3. TEM images showed that particles annealed at 873 K present particles with highly homogeneous sizes in the range from 5 nm to 10 nm and those annealed at 1273 K show particles with quite different sizes from 5 nm to 100 nm, with a wide size distribution. PAC and magnetization results show that samples annealed at 873 and 1273 K are paramagnetic. Magnetization measurements show no indication of blocking temperatures for all samples down to 2 K and the presence of antiferromagnetic correlations.

  9. Critically evaluated theoretical energies, lifetimes, hyperfine constants, and multipole polarizabilities in {sup 87}Rb

    SciTech Connect

    Safronova, M. S.; Safronova, U. I.

    2011-05-15

    Systematic study of Rb atomic properties is carried out using a high-precision relativistic all-order method. Excitation energies of the ns, np, nd, and nf (n{<=}10) states in neutral rubidium are evaluated. Reduced matrix elements, oscillator strengths, transition rates, and lifetimes are determined for the levels up to n=8. Recommended values and estimates of their uncertainties are provided for a large number of electric-dipole transitions. Electric-dipole (5s-np, n=5-26), electric-quadrupole (5s-nd{sub j}, n=4-26), and electric-octupole (5s-nf{sub j}, n=4-26) matrix elements are calculated to obtain the ground state E1, E2, and E3 static polarizabilities. Scalar polarizabilities of the ns, np, and nd states, and tensor polarizabilities of the np{sub 3/2} and nd excited states of Rb are evaluated. The hyperfine A and B values in {sup 87}Rb are determined for the first low-lying levels up to n=9. These calculations provide recommended values critically evaluated for their accuracy for a number of Rb atomic properties useful for a variety of applications.

  10. Helium Pressure Shift of the Hyperfine Clock Transition in Hg-201(+)

    NASA Technical Reports Server (NTRS)

    Larigani, S. Taghavi; Burt, E. A.; Tjoelker, R. L.

    2010-01-01

    There are two stable odd isotopes of mercury with singly ionized hyperfine structure suitable for a microwave atomic clock: Hg-199(+) and Hg-201(+). We are investigating the viability of a trapped ion clock based on Hg-201(+) in a configuration that uses a buffer gas to increase ion loading efficiency and counter ion heating from rf trapping fields. Traditionally, either helium or neon is used as the buffer gas at approx. 10(exp -5) torr to confine mercury ions near room temperature. In addition to the buffer gas, other residual background gasses such as H2O, N2, O2, CO, CO2, and CH2 may be present in trace quantities. Collisions between trapped ions and buffer gas or background gas atoms/molecules produce a momentary shift of the ion clock transition frequency and constitute one of the largest systematic effects in this type of clock. Here we report an initial measurement of the He pressure shift in Hg-201(+) and compare this to Hg-199(+).

  11. A SETI Search of Nearby Solar-Type Stars at the 203-GHz Positronium Hyperfine Resonance

    NASA Technical Reports Server (NTRS)

    Steffes, Paul G.; DeBoer, David R.

    1994-01-01

    The development of advanced millimeter-wave technology has made it possible to construct low-noise receivers and high-power transmitters comparable to those available at much lower frequencies. This technology, plus certain physical characteristics of the millimeter-wave spectrum, suggests possible advantages for use of this wavelength range for interstellar communications. As a result, a Search for ExtraTerrestrial Intelligence(SETI) type search has been conducted for narrow-bandwidth signals at frequencies near the positronium hyperfine spectral line (203.385 GHz), a potential natural reference frequency. A total of 40 solar-type stars within 23 parsecs were observed, in addition to three locations near the galactic center. No detections were made at the detection threshold of 2.3 x 10(exp -19) W/sq m in each of two orthogonal linear polarizations Future observations will be made with a higher resolution Fast Fourier Transform Spectrum Analyzer (FFTSA), which should improve sensitivity by an order of magnitude and reduce required observing time.

  12. Anomalous magnetic hyperfine structure of the 229Th ground-state doublet in muonic atoms

    NASA Astrophysics Data System (ADS)

    Tkalya, E. V.

    2016-07-01

    The magnetic hyperfine (MHF) splitting of the ground and low-energy 3 /2+(7.8 ±0.5 eV) levels in the 229Th nucleus in the muonic atom (μ1S1 /2 -229Th) * is calculated considering the distribution of the nuclear magnetization in the framework of the collective nuclear model with wave functions of the Nilsson model for the unpaired neutron. It is shown that (a) deviation of the MHF structure of the isomeric state exceeds 100% from its value for a pointlike nuclear magnetic dipole (the order of sublevels is reversed); (b) partial inversion of levels of the 229Th ground-state doublet and spontaneous decay of the ground state to the isomeric state occur; (c) the E 0 transition, which is sensitive to differences in the mean-square charge radii of the doublet states, is possible between mixed sublevels with F =2 ; and (d) MHF splitting of the 3 /2+ isomeric state may be in the optical range for certain values of the intrinsic gK factor and a reduced probability of a nuclear transition between the isomeric and the ground states.

  13. Composite Sequences for Triple-dot Qubits that Compensate for Miscalibration and Hyperfine Gradients

    NASA Astrophysics Data System (ADS)

    Ladd, Thaddeus

    2014-03-01

    Exchange-only qubits defined in triple quantum dots form a promising means for all-electrical semiconductor quantum control, but they suffer from both charge noise and random magnetic field gradients. Low-frequency noise sources can be compensated using composite sequences, but the development of such sequences is constrained by the fact that exchange energies are always positive and the control axes are non-orthogonal. Here, we present the results of both analytical approaches and computational searches for composite pulse sequences, which compensate for simultaneous low-frequency miscalibration (due to fixed random electric fields) and hyperfine effects (due to nuclear magnetic fields) in a single triple-dot qubit. We also present compensation sequences for multi-qubit gates. These results can substantially improve the working fidelity of quantum operations in semiconductor quantum dot devices. Sponsored by United States Department of Defense. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressly or implied, of the United States Department of Defense or the U.S. Government.

  14. Coupling and control in coherently driven and asymmetrically synchronized hybrid electron-nuclear spin system

    NASA Astrophysics Data System (ADS)

    Berec, V.

    2016-02-01

    We study the coupling and control adaptation of a hybrid electron-nuclear spin system using the laser mediated proton beam in MeV energy regime. The asymmetric control mechanism is based on exact optimization of both: the measure of exchange interaction and anisotropy of the hyperfine interaction induced in the resonance with optimal channeled protons (CP) superfocused field, allowing manipulation over arbitrary localized spatial centers while addressing only the electron spin. Using highly precise and coherent proton channeling regime we have obtained efficient pulse shaping separator technique aimed for spatio-temporal engineering of quantum states, introducing a method for control of nuclear spins, which are coupled via anisotropic hyperfine interactions in isolated electron spin manifold, without radio wave (RW) pulses. The presented method can be efficiently implemented in synchronized spin networks with the purpose to facilitate preservation and efficient transfer of experimentally observed quantum particle states, contributing to the overall background noise reduction.

  15. Measurements of deuterium quadrupole coupling in propiolic acid and fluorobenzenes using pulsed-beam Fourier transform microwave spectrometers

    NASA Astrophysics Data System (ADS)

    Sun, Ming; Sargus, Bryan A.; Carey, Spencer J.; Kukolich, Stephen G.

    2015-04-01

    The pure rotational spectra of deuterated propiolic acids (HCCCOOD and DCCCOOH), 1-fluorobenzene (4-d1), and 1,2-difluorobenzene (4-d1) in their ground states have been measured using two Fourier transform microwave (FTMW) spectrometers at the University of Arizona. For 1-fluorobenzene (4-d1), nine hyperfine lines of three different ΔJ = 0 and 1 transitions were measured to check the synthesis method and resolution. For 1,2-difluorobenzene (4-d1), we obtained 44 hyperfine transitions from 1 to 12 GHz, including 14 different ΔJ = 0, 1 transitions. Deuterium quadrupole coupling constants along the three principal inertia axes were well determined. For deuterated propiolic acids, 37 hyperfine lines of Pro-OD and 59 hyperfine lines of Pro-CD, covering 11 and 12 different ΔJ = - 1, 0, 1 transitions, respectively, were obtained from 5 to 16 GHz. Deuterium quadrupole coupling constants along the three inertia axes were well resolved for Pro-OD. For Pro-CD, only eQqaa was determined due to the near coincidence of the CD bond and the least principal inertia axis. Some measurements were made using a newer FTMW spectrometer employing multiple free induction decays as well as background subtraction. For 1-fluorobenzene (4-d1) and 1,2-difluorobenzene (4-d1), a very large-cavity (1.2 m mirror dia.) spectrometer yielded very high resolution (2 kHz) spectra.

  16. NMR Spectra Transformed by Electron-Nuclear Coupling as Indicator of Structural Peculiarities of Magnetically Active Molecular Systems.

    PubMed

    Voronov, Vladimir K

    2016-09-01

    The peculiarities of nuclear spin relaxation in the paramagnetic systems have been analyzed taking into account the exchange processes. The analysis is based on the modified Solomon-Bloembergen equations. In this line, the conditions of detecting of the NMR signals of samples are discussed depending on resonance frequency of the NMR spectrometer and characteristic relaxation time. On this basis, (1)H NMR spectra of cobalt semiquinolate complex have been analyzed. It has been shown that the satellite signals observed in the spectrum are caused by hyperfine coupling of the tert-butyl group protons with α and β states (localized on pz orbital of the aromatic carbon) of unpaired electron spin. The relaxation process of the resonance protons is controlled by paramagnetic dipole-dipole coupling. The contact hyperfine coupling does not contribute to the paramagnetic broadening. A mechanism involving paramagnetic molecular structures, which are responsible for intramolecular exchange processes in the cobalt semiquinolate complex, is given. PMID:27513208

  17. Oxoferryl porphyrin cation radicals in model systems: Evidence for variable metal-radical spin coupling

    NASA Astrophysics Data System (ADS)

    Bill, E.; Bominaar, E. L.; Ding, X.-Q.; Trautwein, A. X.; Winkler, H.; Mandon, D.; Weiss, R.; Gold, A.; Jayaraj, K.; Toney, G. E.

    1990-07-01

    Magnetic properties of frozen solutions of highly oxidized iron porphyrin complexes were investigated by EPR and Mössbauer spectroscopy. The Mössbauer spectra, recorded at low temperatures in various magnetic fields, were analyzed on the basis of spin Hamiltonian simulations. Spin coupling between ferryl iron (FeIV) and porphyrin cation radical was taken into account explicitly. Hyperfine and spin-coupling parameters are given for several complexes, together with zero-field parameters. One of the complexes exhibits weak spin coupling, it is the first model system exhibiting properties comparable to those of the oxoferryl cation radical enzyme Horse Radish Peroxidase I.

  18. Hyperfine structure constants of singly ionized manganese obtained from analysis of Fourier Transform spectra

    NASA Astrophysics Data System (ADS)

    Townley-Smith, Keeley; Nave, Gillian; Imperial College London

    2016-01-01

    There is an on-going project in the Atomic Spectroscopy Group at NIST to obtain comprehensive spectral data for all of the singly ionized iron group elements and acquire more accurate energy levels, wavelengths and hyperfine structure (HFS) constants. The heavy abundance of the iron group elements and their contributions to a wide range of stellar spectra makes them of interest for astrophysical observations.Existing spectroscopic data for Mn are insufficient to model spectra obtained from HgMn stars such as HD 175640. Since manganese has an odd number of nucleons, its spectral lines generally exhibit HFS, a relativistic effect due to interaction between the magnetic moment of the nucleus and the orbiting electrons. If proper treatment of line broadening effects such as HFS is not taken, there is a poor fit of the lines in stellar spectra, leading to an overestimate of the abundance of Mn. The abnormally high abundance of manganese in HgMn stars means both weak and strong transitions are important. Weak lines may not be observed in the laboratory, but HFS constants for them can be derived from stronger transitions that combine with the two levels involved in the weak transition.Holt et al. (1999) measured HFS constants for 56 energy levels using laser spectroscopy. We have analyzed Fourier Transform spectra of a high current Mn/Ni hollow cathode lamp to obtain magnetic dipole A constants levels of Mn II. The A constants of Holt et al. (1999, MNRAS 306, 1007) for the z5P, z7P2, a5P and z5F levels were the starting point for our analysis, from which we derived A constants for 71 energy levels, including 51 previously unstudied levels. Our A constant for the a7S3 ground level differs by 5x10-4 cm-1 from that of Blackwell-Whitehead et al. (2005, ApJS 157, 402) and has a factor of 6 lower uncertainty.

  19. Ortho-para mixing hyperfine interaction in the H2O+ ion and nuclear spin equilibration.

    PubMed

    Tanaka, Keiichi; Harada, Kensuke; Oka, Takeshi

    2013-10-01

    The ortho to para conversion of water ion, H2O(+), due to the interaction between the magnetic moments of the unpaired electron and protons has been theoretically studied to calculate the spontaneous emission lifetime between the ortho- and para-levels. The electron spin-nuclear spin interaction term, Tab(SaΔIb + SbΔIa) mixes ortho (I = 1) and para (I = 0) levels to cause the "forbidden" ortho to para |ΔI| = 1 transition. The mixing term with Tab = 72.0 MHz is 4 orders of magnitude higher for H2O(+) than for its neutral counterpart H2O where the magnetic field interacting with proton spins is by molecular rotation rather than the free electron. The resultant 10(8) increase of ortho to para conversion rate possibly makes the effect of conversion in H2O(+) measurable in laboratories and possibly explains the anomalous ortho to para ratio recently reported by Herschel heterodyne instrument for the far-infrared (HIFI) observation. Results of our calculations show that the ortho ↔ para mixings involving near-degenerate ortho and para levels are high (∼10(-3)), but they tend to occur at high energy levels, ∼300 K. Because of the rapid spontaneous emission, such high levels are not populated in diffuse clouds unless the radiative temperature of the environment is very high. The low-lying 101 (para) and 111 (ortho) levels of H2O(+) are mixed by ∼10(-4) making the spontaneous emission lifetime for the para 101 → ortho 000 transition 520 years and 5200 years depending on the F value of the hyperfine structure. Thus the ortho ↔ para conversion due to the unpaired electron is not likely to seriously affect thermalization of interstellar H2O(+) unless either the radiative temperature is very high or number density of the cloud is very low. PMID:23530629

  20. Magnetic and hyperfine properties of Fe2P nanoparticles dispersed in a porous carbon matrix

    NASA Astrophysics Data System (ADS)

    Viali, G. L.; Gonçalves, G. R.; Passamani, E. C.; Freitas, J. C. C.; Schettino, M. A.; Takeuchi, A. Y.; Larica, C.

    2016-03-01

    Structural and magnetic properties of nanocomposite, consisting of Fe2P particles dispersed in a porous carbon matrix, have fully been investigated using X-ray diffraction, Mössbauer and ac and dc magnetization measurements. Besides production of the nanocomposite, using an activated carbon (prepared by chemical activation of a char with H3PO4), impregnation with a Fe3+ salt in aqueous medium and subsequent heat treatments under N2 flow, we found a formation of hexagonal Fe2-xP and orthorhombic FeP in a mass ratio of 4:1, respectively. Low temperature Mössbauer spectra revealed that a large fraction (ca. 28%) of the material is in the paramagnetic state, suggesting that part of the Fe2-xP phase appears in the form of very small particles. A metamagnetic phase transition was also observed for non-stoichiometric Fe2-xP nanoparticles. It is observed at about 150 K, well below the ordering temperature of the Fe2P phase (230 K), and is dependent on the dc-probe fields. Also, the Fe2-xP nanoparticles were found to have a hard-like magnetic character at low temperatures, with coercive field HC of 1.3 KOe. Considering these interesting magnetic and hyperfine properties and also the large specific surface area of the porous carbon matrix, which is not severely reduced after impregnation with the Fe-containing compounds, one may point to promising technological applications of the produced nanocomposite.

  1. High Resolution Rotational Spectroscopy of Zeeman & Hyperfine Effects in PbF & YbF

    NASA Astrophysics Data System (ADS)

    Mawhorter, Richard; Baum, Alex; Murphy, Benjamin; Sears, Trevor; Shafer-Ray, N. E.; Alphei, Lukas; Grabow, Jens-Uwe

    2012-06-01

    Motivated by the ongoing search for the CP-violating electron electric dipole moment (e-EDM), rotational spectra of the radicals^ 207Pb^19F and ^208Pb^19F were measured using a supersonic jet Fourier transform microwave spectrometer. Zeeman splitting was examined for 10 ^207PbF and 9 ^208PbF J = .5ex1 -.1em/ -.15em.25ex2 and J = ^3/2 transitions using Helmholtz coils and magnetic fields up to ˜4 Gauss. Transitions were observed with 0.5 kHz accuracy and 6 kHz pair resolution over a range of 2 -- 26.5 GHz. The observation of these field dependent spectra allowed for the determination of the two body fixed g-factors, G and G, of the electronic wave function. This is an important step in a possible future e-EDM experiment using either the ^207PbF or ^208PbF molecule, and our results compare reasonably well with recently calculated values. Observing the nuclear quadrupole hyperfine structure can also help characterize the critical electric field at the heavy atom nucleus in unstable but long-lived ^205PbF as well as ^173YbF. Energy level predictions based on our detailed studies of the 4 stable PbF isotopologues as well as previous optical and microwave spectra of YbF will facilitate upcoming experimental studies and may also uncover nearby states of opposite parity which could also greatly benefit the eEDM search.

  2. HYPERFINE-DEPENDENT gf-VALUES OF Mn I LINES IN THE 1.49-1.80 μm H BAND

    SciTech Connect

    Andersson, M.; Hutton, R.; Zou, Y.; Grumer, J.; Brage, T.; Ryde, N.; Blackwell-Whitehead, R.; Jönsson, P.

    2015-01-01

    The three Mn I lines at 17325, 17339, and 17349 Å are among the 25 strongest lines (log (gf) > 0.5) in the H band. They are all heavily broadened due to hyperfine structure, and the profiles of these lines have so far not been understood. Earlier studies of these lines even suggested that they were blended. In this work, the profiles of these three infrared (IR) lines have been studied theoretically and compared to experimental spectra to assist in the complete understanding of the solar spectrum in the IR. It is shown that the structure of these lines cannot be described in the conventional way using the diagonal A and B hyperfine interaction constants. The off-diagonal hyperfine interaction not only has a large impact on the energies of the hyperfine levels, but also introduces a large intensity redistribution among the hyperfine lines, changing the line profiles dramatically. By performing large-scale calculations of the diagonal and off-diagonal hyperfine interaction and the gf-values between the upper and lower hyperfine levels and using a semi-empirical fitting procedure, we achieved agreement between our synthetic and experimental spectra. Furthermore, we compare our results with observations of stellar spectra. The spectra of the Sun and the K1.5 III red giant star Arcturus were modeled in the relevant region, 1.73-1.74 μm, using our theoretically predicted gf-values and energies for each individual hyperfine line. Satisfactory fits were obtained and clear improvements were found using our new data compared with the old available Mn I data. A complete list of energies and gf-values for all the 3d {sup 5}4s({sup 7} S)4d e{sup 6}D - 3d {sup 5}4s({sup 7} S)4f w{sup 6}F hyperfine lines are available as supporting material, whereas only the stronger lines are presented and discussed in detail in this paper.

  3. Huge positive hyperfine fields for Sn impurity atoms on R sites of R T intermetallic compounds (R=rare-earth, T=Fe, Co)

    NASA Astrophysics Data System (ADS)

    Krylov, V. I.; Delyagin, N. N.

    2006-10-01

    The magnetic hyperfine field Bhf of the 119Sn impurity atom on the R site of the RFe 2 (R=Sm, Tb, Tm), TbCo 2, RCo 5 (R=Dy, Ho, Er), GdCo 3 and Gd 2Co 7 intermetallic compounds has been investigated by Mössbauer spectroscopy technique. At 5 K, very large hyperfine fields equal to 46-56 T were observed. The B values are several times larger than commonly observed for Sn in 3d-based magnetic hosts. The hyperfine fields are positive (that is parallel to the 3d magnetic moments direction). The results can be interpreted qualitatively in terms of the theory proposed for the impurity atoms in homogeneous ferromagnetic hosts [J. Kanamori, H. Katayama-Yoshida, K. Terakura, Hyperfine Interact. 8 (1981) 573; J. Kanamori, H. Katayama-Yoshida, K. Terakura, Hyperfine Interact. 9 (1981) 363; M. Akai, H. Akai, J. Kanamori, J. Phys. Soc. Jpn. 54 (1985) 4246; S. Blügel, H. Akai, R. Zeller, P.H. Dederichs, Phys. Rev. B 35 (1987) 3271], when it is considered that the splitting between bonding and antibonding hybrid states is strongly dependent on the interatomic distance. As the distance between the probe atom and neighboring magnetic atoms increases, the population of the antibonding states grows and, as a consequence, the corresponding positive contribution to the B increases sharply. For Sn atom the positive contribution to the B dominates when the interatomic distance exceeds 0.28-0.29 nm.

  4. Group theoretical study of the radical cation of methane: The effect of tunneling motions on the hyperfine interaction

    NASA Astrophysics Data System (ADS)

    Matsushita, Michio; Momose, Takamasa; Shida, Tadamasa; Knight, Lon B., Jr.

    1995-09-01

    The electron spin resonance (ESR) spectrum of CH+4 indicates that some large amplitude tunneling motions among Jahn-Teller distorted structures make the four protons equivalent. A group theoretical study using the permutation-inversion (PI) group is performed to analyze the hyperfine interaction of the nonrigid CH+4. It is shown that three patterns of the interaction are possible depending upon the type of tunneling motions. Only one of the three patterns is consistent with the experimental spectrum, which is presented in the accompanying paper [J. Chem. Phys. 103, 3377 (1995)].

  5. Precise laser frequency scanning using frequency-synthesized optical frequency sidebands - Application to isotope shifts and hyperfine structure of mercury

    NASA Technical Reports Server (NTRS)

    Rayman, M. D.; Aminoff, C. G.; Hall, J. L.

    1989-01-01

    Based on an efficient broadband electrooptic modulator producing RF optical sidebands locked to a stable cavity, a tunable dye laser can be scanned under computer control with frequency-synthesizer precision. Cavity drift is suppressed in software by using a strong feature in the spectrum for stabilization. Mercury isotope shifts are measured with a reproducibility of about 50 kHz. This accuracy of about 1/300 of the linewidth illustrates the power of the technique. Derived hyperfine-structure constants are compared with previous atomic-beam data.

  6. A comparison of the cesium and hydrogen hyperfine frequencies by means of Loran-C and portable clocks

    NASA Technical Reports Server (NTRS)

    Reinhardt, V. S.; Lavanceau, J.

    1974-01-01

    A comparison of the hydrogen and cesium hyperfine frequencies is made using a hydrogen maser calibrated directly against the Flexible Bulb Large Storage Box Hydrogen Maser and a Hewlett-Packard portable high performance cesium clock calibrated indirectly against the USNO Master Clock via a Loran-C link. The portable cesium clock is transported from the USNO to Harvard University in operating condition. This allows the evaluation of the portable clock's performance under transport. Data are presented on the epoch and frequency stability of the portable clock under transport as well as the usefulness of a closure measurement in determining clock drift.

  7. Doppler-Free Spectroscopy Measurements of Isotope Shifts and Hyperfine Components of Near-IR Xenon Lines

    SciTech Connect

    Mazouffre, S.; Pawelec, E.; Tran Bich, N.; Sadeghi, N.

    2006-01-15

    Xenon is currently used as propellant gas in electric thrusters, in which ejection of corresponding ions produces the desired thrust. As such a gas contains 9 stable isotopes, a non-intrusive determination of the velocity distribution function of atoms and ions in the thruster plasma plume, by means of absorption or fluorescence techniques, requires a precise knowledge of the line structure. We used Doppler-free Lamb-dip spectroscopy to determine isotopic shifts and hyperfine components of odd isotopes of several spectral lines of Xe atom and Xe+ ion in the 825 - 835 nm range.

  8. The Molecular Frame Electric Dipole Moment and Hyperfine Interactions in Hafnium Fluoride, HfF

    NASA Astrophysics Data System (ADS)

    Le, Anh; Steimle, Timothy C.; Skripnikov, Leonid; Titov, Anatoly V.

    2013-06-01

    The identification of HfF^{+} as a possible candidate for a d_{e}} measurement has stimulated new interest in the spectroscopy of both HfF^{+} and neutral HfF. Studies of the neutral are relevant because photoionization schemes can be used to produce the cations. More importantly, computational methodologies used to predict the electronic wavefunction of HfF^{+} can be effectively assessed by making a comparison of predicted and experimental properties of the neutral, which are more readily determinable. The (1,0)[17.9]2.5 -X^{2}Δ_{3/2} band of hafnium monofluoride (HfF) has been recorded using high-resolution laser-induced fluorescence spectroscopy both field-free and in the presence of a static electric field. The field-free spectra of ^{177}HfF, ^{179}HfF, and ^{180}HfF were model to generate a set of fine and hyperfine parameters for the X^{2}Δ_{3/2} (v=0) and [17.9]2.5 (v=1) states. The observed optical Stark shifts for the ^{180}HfF isotopologue were analyzed to produce the molecular frame electric dipole moments of 1.66(1)D and 0.419(7)D for the X^{2}Δ_{3/2} and [17.9]2.5 states, respectively. A two-step ab initio calculation consisting of a two-component generalized relativistic effective core potential calculation (GRECP) followed by a restoration of the proper four-component wavefunction was performed to predict the properties of ground state HfF. B. J. Barker, I. O. Antonov, V. E. Bondybey, and M. C. Heaven, J. Chem. Phys., 134, 201102 (2011). K. C. Cossel, D. N. Gresh, L. C. Sinclair, T. Coffey, L. V. Skripnikov, A. N. Petrov, N. S. Mosyagin, A. V. Titov, R. W. Field, E. R. Meyer, E. A. Cornell and J. Ye, Chem. Phys. Lett., 546, 1 (2012). M. Grau, A. E. Leanhardt, H. Loh, L. C. Sinclair, R. P. Stutz, T. S. Yahn, and E. A. Cornell, J. Mol. Spectroc., 272, 32 (2012). H. Loh, R. P. Stutz, T. S. Yahn, H. Looser, R. W. Field, and E. A. Cornell, J. Mol. Spectroc.,276-277, 49 (2012).

  9. Hyperfine Structure of the Singlet DEUTERIUM(2) - Triplet HYDROGEN(4) Transition in PRASEODYMIUM:LANTHANUM - Measured Using Photon Echo Modulation Spectroscopy.

    NASA Astrophysics Data System (ADS)

    Whittaker, Edward Anthony

    After a brief description of the relevant physical properties of the Pr('3+);LaF(,3) system, the method of photon echo modulation spectroscopy is explained. The results of an experiment to measure the hyperfine structure of the ('1)D(,2)((GAMMA)(,1))-('3)H(,4)((GAMMA)(,1)) transition in Pr('3+):LaF(,3) using the echo modulation method are presented. The hyperfine transition frequencies and linewidths for the ('1)D(,2) level were found to be 3.72 MHz (70 kHz), 4.79 MHz (60 kHz) and 8.51 MHz (30 kHz). A separate result gives new information concerning the relative orientation of the principle axes systems of the effective hyperfine Hamiltonians of the ('1)D(,2)-('3)H(,4) levels. This information is displayed using a new graphical method and suggests that there is intrinsically a great deal of symmetry in the relative orientation parameter.

  10. Local probe studies of Fe hyperfine field in CaFe2As2 by time differential perturbed angular distribution (TDPAD) spectroscopy and ab initio methods

    NASA Astrophysics Data System (ADS)

    Mohanta, S. K.; Mishra, S. N.; Davane, S. M.; Kumar, Neeraj; Thamizhavel, A.; Layek, S.; Hossain, Z.; Srivastava, S. K.

    2013-03-01

    Applying the γ-ray perturbed angular distribution technique we have measured the magnetic hyperfine field and spin relaxation time of recoil implanted 54Fe in single and polycrystalline CaFe2As2 over the temperature range 20-360 K, encompassing both tetragonal and orthorhombic structural phases of the material. The magnetic response of Fe in the high temperature tetragonal phase (T ⩾ 180 K), show Curie-Weiss type local susceptibility and Korringa like spin relaxation, reflecting the presence of localized moment on Fe. In the orthorhombic phase, the spin rotation spectra of 54Fe show two magnetic hyperfine field components, both exhibiting quasi two dimensional magnetic ordering. The experimentally measured hyperfine field and Fe moment show good agreement with results obtained from ab initio calculations performed within the frame work of local spin density approximation (LSDA).

  11. Coupling erbium spins to a three-dimensional superconducting cavity at zero magnetic field

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Hui; Fernandez-Gonzalvo, Xavier; Longdell, Jevon J.

    2016-08-01

    We experimentally demonstrate the coupling at zero magnetic field of an isotopically pure erbium-doped yttrium orthosilicate crystal (167Er:YSO ) to a three-dimensional superconducting cavity with a Q factor of 105. A tunable loop-gap resonator is used and its resonance frequency is tuned to observe the hyperfine transitions of the erbium sample. The observed spectrum differs from what is predicted by the published spin Hamiltonian parameters. The narrow cavity linewidth also enables the observation of asymmetric line shapes for these hyperfine transitions. Such a broadly tunable superconducting cavity (from 1.6 to 4.0 GHz in the current design) is a promising device for building hybrid quantum systems.

  12. Rotational Spectroscopy of HB 33S: The Quadrupole Coupling Constant of 33S in Thioborine

    NASA Astrophysics Data System (ADS)

    Bizzocchi, L.; Degli Esposti, C.; Dore, L.

    2002-10-01

    The unstable HBS molecule has been produced in the gas phase by a high-temperature reaction between crystalline boron and hydrogen sulfide. Ground state rotational spectra have been observed in the millimeter-wave region, from 75 to 460 GHz, for the previously unobserved H 11B 33S and H 10B 33S isotopic species. The analysis of the hyperfine structure produced by the 10/11B and 33S nuclear spins in the low- J rotational transitions has yielded the first evaluation of the quadrupole coupling constant of 33S in the thioborine molecule, which was 6.361(15) MHz in H 11B 33S and 6.329(17) MHz in H 10B 33S. In addition, further measurements have been performed for the most abundant isotopomers H 10/11B 32/34S, for which improved values of rotational, centrifugal, and hyperfine structure constants have been determined.

  13. Investigation of hyperfine interactions in RMO3 (R =La, Nd; M =Cr, Fe) antiferromagnetic perovskite oxides using PAC spectroscopy

    NASA Astrophysics Data System (ADS)

    Carbonari, A. W.; Cavalcante, F. H. M.; Junqueira, A. C.; Leite, D. M. T.; Saxena, R. N.; Mestnik-Filho, J.

    The local magnetic interaction at the transition metal sites in RMO3 (R=La, Nd; M=Cr, Fe) compounds has been investigated by perturbed angular correlation (PAC) technique using 181Hf→181Ta probe nuclei. The present measurements cover a temperature range from 10 K to 1000 K. Above the respective Neel temperature, each compound shows a unique quadrupolar frequency that decreases linearly with temperature. These interactions were assigned to the radioactive probe substituting Cr or Fe sites. Below TN, a combined electric plus magnetic hyperfine interaction was observed. The magnetic interaction revealed that the super transferred hyperfine fields on 181Ta at the Cr sites in (La,Nd)CrO3 extrapolated to 0 K, are much smaller than the corresponding values at Fe sites in (La,Nd)FeO3. This difference was attributed to different distribution of d electrons in Cr3+ (3d3) and Fe3+ (3d5) ions in each compound. As the fields for Nd compounds are smaller than those for La compounds, the role of rare-earth ions in the magnetism of these oxides is also discussed.

  14. Investigation of hyperfine interactions in RMO 3 (R = La, Nd; M = Cr, Fe) antiferromagnetic perovskite oxides using PAC spectroscopy

    NASA Astrophysics Data System (ADS)

    Carbonari, A. W.; Cavalcante, F. H. M.; Junqueira, A. C.; Leite, D. M. T.; Saxena, R. N.; Mestnik-Filho, J.

    2007-07-01

    The local magnetic interaction at the transition metal sites in RMO3 (R = La, Nd; M = Cr, Fe) compounds has been investigated by perturbed angular correlation (PAC) technique using 181Hf→181Ta probe nuclei. The present measurements cover a temperature range from 10 K to 1000 K. Above the respective Néel temperature, each compound shows a unique quadrupolar frequency that decreases linearly with temperature. These interactions were assigned to the radioactive probe substituting Cr or Fe sites. Below T N , a combined electric plus magnetic hyperfine interaction was observed. The magnetic interaction revealed that the super transferred hyperfine fields on 181Ta at the Cr sites in (La,Nd)CrO3 extrapolated to 0 K, are much smaller than the corresponding values at Fe sites in (La,Nd)FeO3. This difference was attributed to different distribution of d electrons in Cr3 + (3d3) and Fe3 + (3d5) ions in each compound. As the fields for Nd compounds are smaller than those for La compounds, the role of rare-earth ions in the magnetism of these oxides is also discussed.

  15. Combining Steady-State and Dynamic Methods for Determining Absolute Signs of Hyperfine Interactions: Pulsed ENDOR Saturation and Recovery (PESTRE)

    PubMed Central

    Doan, Peter E.

    2010-01-01

    The underlying causes of asymmetric intensities in Davies pulsed ENDOR spectra that are associated with the signs of the hyperfine interaction are reinvestigated. The intensity variations in these asymmetric ENDOR patterns are best described as shifts in an apparent baseline intensity that occurs dynamically following on-resonance ENDOR transitions. We have developed an extremely straightforward multi-sequence protocol that is capable of giving the sign of the hyperfine interaction by probing a single ENDOR transition, without reference to its partner transition. This technique, Pulsed ENDOR Saturatation and Recovery (PESTRE) monitors dynamic shifts in the ‘baseline’ following measurements at a single RF frequency (single ENDOR peak), rather than observing anomalous ENDOR intensity differences between the two branches of an ENDOR response. These baseline shifts, referred to as dynamic reference levels (DRLs), can be directly tied to the electron spin manifold from which that ENDOR transition arises. The application of this protocol is demonstrated on 57Fe ENDOR of a 2Fe-2S ferredoxin. We use the 14N ENDOR transitions of the S = 3/2 [Fe(II)NO]2+ center of the non-heme iron enzyme, anthranilate dioxygenase (AntDO) to examine the details of the relaxation model using PESTRE. PMID:21075026

  16. Hyperfine-changing transitions in {sup 3}He II and other one-electron ions by electron scattering

    SciTech Connect

    Bartschat, Klaus; Sadeghpour, H. R. E-mail: hrs@cfa.harvard.edu

    2014-06-10

    We consider the spin-exchange (SE) cross-section in electron scattering from {sup 3}He II, which drives the hyperfine-changing 3.46 cm (8.665 GHz) line transition. Both the analytical quantum defect method—applicable at very low energies—and accurate R-matrix techniques for electron-He{sup +} scattering are employed to obtain SE cross-sections. The quantum defect theory is also applied to electron collisions with other one-electron ions in order to demonstrate the utility of the method and derive scaling relations. At very low energies, the hyperfine-changing cross-sections due to e-He{sup +} scattering are much larger in magnitude than for electron collisions with neutral hydrogen, hinting at large rate constants for equilibration. Specifically, we obtain rate coefficients of K(10 K) = 1.10 × 10{sup –6} cm{sup 3} s{sup –1} and K(100 K) = 3.49 × 10{sup –7} cm{sup 3} s{sup –1}.

  17. The magnetic behavior of the intermetallic compound NdMn2Ge2 studied by magnetization and hyperfine interactions measurements

    NASA Astrophysics Data System (ADS)

    Bosch-Santos, B.; Carbonari, A. W.; Cabrera-Pasca, G. A.; Saxena, R. N.; Freitas, R. S.

    2015-05-01

    The magnetic behavior of the intermetallic compound NdMn2Ge2 was investigated by bulk magnetization measurements and measurements of hyperfine interactions using perturbed γ-γ angular correlation (PAC) spectroscopy. Magnetization measurements indicate the presence of four magnetic transitions associated with the Mn and Nd magnetic sublattices. At high temperatures, magnetic measurements show a change in the slope of the magnetization due to an antiferromagnetic transition around TN ˜ 425 K and a well defined ferromagnetic transition at TC ˜ 320 K. Moreover, at ˜210 K a peak is observed in the magnetization curve, which is assigned to the reorientation of the Mn spin, and at ˜25 K an increase in the magnetic moment is also observed, which is ascribed to the ordering of Nd ions. PAC measurements using 140La(140Ce) and 111In(111Cd) probe nuclei allowed the determination of the temperature dependence of the magnetic hyperfine field (Bhf) at Nd and Mn sites, respectively. PAC results with 111Cd probe nuclei at Mn sites show that the dependence of Bhf with temperature follows the expected behavior for the host magnetization associated with the magnetic ordering of Mn ions. From these results, the antiferromagnetic transition followed by a ferromagnetic ordering is clearly observed. PAC results with 140Ce probe nuclei at Nd sites, however, showed a strong deviation from the Brillouin function, which is attributed to the Ce 4f-electron contribution to Bhf.

  18. Large increase of magnetic hyperfine fields of 5sp-shell impurities in ferromagnets after vacancy trapping

    NASA Astrophysics Data System (ADS)

    de Waard, H.; Hafemeister, D. W.; Niesen, L.; Pleiter, F.

    1981-08-01

    Vacancy trapping by 119Sb impurities implanted in Ni, Co, and Fe gives rise to large changes of the magnetic hyperfine fields Bhf of the 119Sn daughter nuclei. We have measured the following values for the normal substitutional and the vacancy-associated impurity hyperfine fields (in T): SnNi SnCo(fcc) SnFe B(subs)hf +2.06(2) -1.89(2) -8.60(2) B(vac)hf +4.7-7.1 +7.3-14.5 -2.8(2) In all cases, the vacancies associated with the impurities could be "frozen in" up to high temperatures by decoration with post-implanted helium atoms. The substantial increase of the fields can be understood in terms of the conduction-electron polarization model of Blandin and Campbell.

  19. Correlated wave functions and hyperfine splittings of the 2 s state of muonic sup 3,4 He atoms

    SciTech Connect

    Chen, M. )

    1992-02-01

    The correlated wave functions of the 2{ital s} state, (1{ital s}){sub {ital e}}(2{ital s}){sub {mu}} of muonic {sup 4}He and {sup 3}He atoms are calculated by the variational approach, employing an improved set of the Hylleraas-type basis functions to study the 2{ital s} state of muonic He atoms. The energy and radial expectation values are calculated. Our proposed wave functions for the muonic {sup 4}He and {sup 3}He atoms are good enough to describe the electron and muon at small, intermediate, and large values of radial coordinates. The hyperfine splittings of the (1{ital s}){sub {ital e}}(2{ital s}){sub {mu}} muonic {sup 4}He and {sup 3}He atoms are also presented. Including relativistic, QED, and other corrections up to {ital O}({alpha}{sup 2}), we arrive at the values {Delta}{nu}= 4287.01{plus minus}0.10 and 4052.64{plus minus}0.10 MHz for the total hyperfine splittings of the 2{ital s} state of muonic {sup 4}He and {sup 3}He atoms, respectively.

  20. Hyperfine quenching of the metastable {sup 3}P{sub 0,2} states in divalent atoms

    SciTech Connect

    Porsev, Sergey G.; Derevianko, Andrei

    2004-04-01

    Hyperfine quenching rates of the lowest-energy metastable {sup 3}P{sub 0} and {sup 3}P{sub 2} states of Mg, Ca, Sr, and Yb atoms are computed. The calculations are carried out using ab initio relativistic many-body methods. The computed lifetimes may be useful for designing novel ultraprecise optical clocks and trapping experiments with the {sup 3}P{sub 2} fermionic isotopes. The resulting natural widths of the {sup 3}P{sub 0}-{sup 1}S{sub 0} clock transition are 0.44 mHz for {sup 25}Mg, 2.2 mHz for {sup 43}Ca, 7.6 mHz for {sup 87}Sr, 43.5 mHz for {sup 171}Yb, and 38.5 mHz for {sup 173}Yb. Compared to the bosonic isotopes, the lifetime of the {sup 3}P{sub 2} states in fermionic isotopes is noticeably shortened by the hyperfine quenching but still remains long enough for trapping experiments.

  1. Observation of hyperfine mixing in measurements of a magnetic octupole decay in isotopically pure nickel-like 129Xe and 132Xe ions

    SciTech Connect

    Trabert, E; Beiersdorfer, P; Brown, G V

    2006-12-21

    We present measurements of high statistical significance of the rate of the magnetic octupole (M3) decay in nickel-like ions of isotopically pure {sup 129}Xe and {sup 132}Xe. On {sup 132}Xe, an isotope with zero nuclear spin and therefore without hyperfine structure, the lifetime of the metastable level was established as (15.06 {+-} 0.24) ms. On {sup 129}Xe, an additional fast (2.7 {+-} 0.1 ms) decay component was established that represents hyperfine mixing with a level that decays by electric quadrupole (E2) radiation.

  2. Integrable pair-transition-coupled nonlinear Schrödinger equations

    NASA Astrophysics Data System (ADS)

    Ling, Liming; Zhao, Li-Chen

    2015-08-01

    We study integrable coupled nonlinear Schrödinger equations with pair particle transition between components. Based on exact solutions of the coupled model with attractive or repulsive interaction, we predict that some new dynamics of nonlinear excitations can exist, such as the striking transition dynamics of breathers, new excitation patterns for rogue waves, topological kink excitations, and other new stable excitation structures. In particular, we find that nonlinear wave solutions of this coupled system can be written as a linear superposition of solutions for the simplest scalar nonlinear Schrödinger equation. Possibilities to observe them are discussed in a cigar-shaped Bose-Einstein condensate with two hyperfine states. The results would enrich our knowledge on nonlinear excitations in many coupled nonlinear systems with transition coupling effects, such as multimode nonlinear fibers, coupled waveguides, and a multicomponent Bose-Einstein condensate system.

  3. Integrable pair-transition-coupled nonlinear Schrödinger equations.

    PubMed

    Ling, Liming; Zhao, Li-Chen

    2015-08-01

    We study integrable coupled nonlinear Schrödinger equations with pair particle transition between components. Based on exact solutions of the coupled model with attractive or repulsive interaction, we predict that some new dynamics of nonlinear excitations can exist, such as the striking transition dynamics of breathers, new excitation patterns for rogue waves, topological kink excitations, and other new stable excitation structures. In particular, we find that nonlinear wave solutions of this coupled system can be written as a linear superposition of solutions for the simplest scalar nonlinear Schrödinger equation. Possibilities to observe them are discussed in a cigar-shaped Bose-Einstein condensate with two hyperfine states. The results would enrich our knowledge on nonlinear excitations in many coupled nonlinear systems with transition coupling effects, such as multimode nonlinear fibers, coupled waveguides, and a multicomponent Bose-Einstein condensate system. PMID:26382492

  4. Helix coupling

    DOEpatents

    Ginell, W.S.

    1982-03-17

    A coupling for connecting helix members in series, which consists of a pair of U-shaped elements, one of which is attached to each helix end with the U sections of the elements interlocked. The coupling is particularly beneficial for interconnecting helical Nitinol elements utilized in thermal actuators or engines. Each coupling half is attached to the associated helix at two points, thereby providing axial load while being easily removed from the helix, and reusable.

  5. Helix coupling

    DOEpatents

    Ginell, William S.

    1989-04-25

    A coupling for connecting helix members in series, which consists of a pair of U-shaped elements, one of which is attached to each helix end with the "U" sections of the elements interlocked. The coupling is particularly beneficial for interconnecting helical Nitinol elements utilized in thermal actuators or engines. Each coupling half is attached to the associated helix at two points, thereby providing axial load while being easily removed from the helix, and reusable.

  6. High-resolution microwave-optical double-resonance spectroscopy of hyperfine splitting of trapped {sup 113}Cd{sup +} ions

    SciTech Connect

    Jelenkovic, B. M.; Chung, S.; Prestage, J. D.; Maleki, L.

    2006-08-15

    We performed double resonance spectroscopy on the ground-state hyperfine splitting of {sup 113}Cd{sup +} ions trapped in a rf linear trap. The ions were optically pumped by UV light from the {sup 106}Cd lamp and cooled by He buffer gas. The ground-state hyperfine splitting was measured to be 15 199 862 855 Hz with the precision of 1.3x10{sup -11}. The uncertainty stems from the error in extrapolation to zero magnetic field and from the resonance linewidth. This value is 3 Hz lower than the previous high-precision measurements by [Tanaka et al., Phys. Rev. A 53, 3982 (1996)], in which the laser light was used for optical excitation. The potential for a new microwave frequency standard based on the 15.2-GHz ground-state hyperfine splitting of {sup 113}Cd{sup +} ions is also discussed. Stability of the hyperfine frequency of {sup 113}Cd{sup +} ion, with microwaves locked to the hydrogen maser, is {approx}2x10{sup -13}{tau}{sup -1/2}.

  7. Hyperfine excitation of linear molecules by para- and ortho-H{sub 2}: Application to the HCl–H{sub 2} system

    SciTech Connect

    Lanza, Mathieu; Lique, François

    2014-10-28

    The determination of hyperfine structure resolved excitation cross sections and rate coefficients due to H{sub 2} collisions is required to interpret astronomical spectra. In this paper, we present several theoretical approaches to compute these data. An almost exact recoupling approach and approximate sudden methods are presented. We apply these different approaches to the HCl–H{sub 2} collisional system in order to evaluate their respective accuracy. HCl–H{sub 2} hyperfine structure resolved cross sections and rate coefficients are then computed using recoupling and approximate sudden methods. As expected, the approximate sudden approaches are more accurate when the collision energy increases and the results suggest that these approaches work better for para-H{sub 2} than for ortho-H{sub 2} colliding partner. For the first time, we present HCl–H{sub 2} hyperfine structure resolved rate coefficients, computed here for temperatures ranging from 5 to 300 K. The usual Δj{sub 1} = ΔF{sub 1} propensity rules are observed for the hyperfine transitions. The new rate coefficients will significantly help the interpretation of interstellar HCl emission lines observed with current and future telescopes. We expect that these new data will allow a better determination of the HCl abundance in the interstellar medium, that is crucial to understand the interstellar chlorine chemistry.

  8. Spin-momentum coupled Bose-Einstein condensates with lattice band pseudospins

    PubMed Central

    Khamehchi, M. A.; Qu, Chunlei; Mossman, M. E.; Zhang, Chuanwei; Engels, P.

    2016-01-01

    The quantum emulation of spin-momentum coupling, a crucial ingredient for the emergence of topological phases, is currently drawing considerable interest. In previous quantum gas experiments, typically two atomic hyperfine states were chosen as pseudospins. Here, we report the observation of a spin-momentum coupling achieved by loading a Bose-Einstein condensate into periodically driven optical lattices. The s and p bands of a static lattice, which act as pseudospins, are coupled through an additional moving lattice that induces a momentum-dependent coupling between the two pseudospins, resulting in s–p hybrid Floquet-Bloch bands. We investigate the band structures by measuring the quasimomentum of the Bose-Einstein condensate for different velocities and strengths of the moving lattice, and compare our measurements to theoretical predictions. The realization of spin-momentum coupling with lattice bands as pseudospins paves the way for engineering novel quantum matter using hybrid orbital bands. PMID:26924575

  9. Spin-momentum coupled Bose-Einstein condensates with lattice band pseudospins.

    PubMed

    Khamehchi, M A; Qu, Chunlei; Mossman, M E; Zhang, Chuanwei; Engels, P

    2016-01-01

    The quantum emulation of spin-momentum coupling, a crucial ingredient for the emergence of topological phases, is currently drawing considerable interest. In previous quantum gas experiments, typically two atomic hyperfine states were chosen as pseudospins. Here, we report the observation of a spin-momentum coupling achieved by loading a Bose-Einstein condensate into periodically driven optical lattices. The s and p bands of a static lattice, which act as pseudospins, are coupled through an additional moving lattice that induces a momentum-dependent coupling between the two pseudospins, resulting in s-p hybrid Floquet-Bloch bands. We investigate the band structures by measuring the quasimomentum of the Bose-Einstein condensate for different velocities and strengths of the moving lattice, and compare our measurements to theoretical predictions. The realization of spin-momentum coupling with lattice bands as pseudospins paves the way for engineering novel quantum matter using hybrid orbital bands. PMID:26924575

  10. Determination of the hyperfine magnetic field in magnetic carbon-based materials: DFT calculations and NMR experiments

    PubMed Central

    Freitas, Jair C. C.; Scopel, Wanderlã L.; Paz, Wendel S.; Bernardes, Leandro V.; Cunha-Filho, Francisco E.; Speglich, Carlos; Araújo-Moreira, Fernando M.; Pelc, Damjan; Cvitanić, Tonči; Požek, Miroslav

    2015-01-01

    The prospect of carbon-based magnetic materials is of immense fundamental and practical importance, and information on atomic-scale features is required for a better understanding of the mechanisms leading to carbon magnetism. Here we report the first direct detection of the microscopic magnetic field produced at 13C nuclei in a ferromagnetic carbon material by zero-field nuclear magnetic resonance (NMR). Electronic structure calculations carried out in nanosized model systems with different classes of structural defects show a similar range of magnetic field values (18–21 T) for all investigated systems, in agreement with the NMR experiments. Our results are strong evidence of the intrinsic nature of defect-induced magnetism in magnetic carbons and establish the magnitude of the hyperfine magnetic field created in the neighbourhood of the defects that lead to magnetic order in these materials. PMID:26434597

  11. Measurement of the blackbody radiation shift of the {sup 133}Cs hyperfine transition in an atomic fountain

    SciTech Connect

    Levi, Filippo; Calonico, Davide; Lorini, Luca; Micalizio, Salvatore; Godone, Aldo

    2004-09-01

    We used a Cs fountain to measure the Stark shift of the ground-state hyperfine transition frequency in cesium (9.2 GHz) due to the electric field of the blackbody radiation. The relative shift at 300 K deduced from our measurements, including the leading and the second-order term in temperature, is (-1.45{+-}0.09)x10{sup -14} and agrees with our recent theoretical evaluation (-1.51{+-}0.07)x10{sup -14} [Micalizio et al. Phys. Rev. A 69, 053401 (2004)]. These values differ from that currently used (-1.735{+-}0.003)x10{sup -14}, with significant implications on frequency standards accuracy, on clocks comparison and on a variety of high-precision physics tests, such as the time stability of fundamental constants.

  12. Direct measurement of excited-state dipole matrix elements using electromagnetically induced transparency in the hyperfine Paschen-Back regime

    NASA Astrophysics Data System (ADS)

    Whiting, Daniel J.; Keaveney, James; Adams, Charles S.; Hughes, Ifan G.

    2016-04-01

    Applying large magnetic fields to gain access to the hyperfine Paschen-Back regime can isolate three-level systems in a hot alkali metal vapors, thereby simplifying usually complex atom-light interactions. We use this method to make the first direct measurement of the |<5 P ||e r ||5 D >| matrix element in 87Rb. An analytic model with only three levels accurately models the experimental electromagnetically induced transparency spectra and extracted Rabi frequencies are used to determine the dipole matrix element. We measure |<5 P3 /2||e r ||5 D5 /2>| =(2.290 ±0 .002stat±0 .04syst) e a0 , which is in excellent agreement with the theoretical calculations of Safronova, Williams, and Clark [Phys. Rev. A 69, 022509 (2004), 10.1103/PhysRevA.69.022509].

  13. Hyperfine structures of the nd /sup 1/D(n = 3 - 8) states of /sup 3/He I

    SciTech Connect

    Brooks, R.L.; Streif, V.F.; Berry, H.G.

    1981-01-01

    We have used the beam-foil quantum beat method to measure the hyperfine structure separations F = 3/2 - 5/2 of the 1snd /sup 1/D states (n = 3 - 8) of /sup 3/He I. We observed the single frequency modulated decay curves of the 1s2p /sup 1/P - 1snd /sup 1/D transitions for times after excitation up to 50 ns, corresponding to 4 to 5 modulation periods. The frequencies obtained (with a precision of 2 to 5%) are compared with other experiments and theory. The frequencies are determined mainly by the singlet-triplet energy separations and mixing factors for the He I D-states. The results agree with the same parameters obtained from other recent level-crossing measurements in strong magnetic field mixing of the singlet-triplet states.

  14. Determination of the hyperfine magnetic field in magnetic carbon-based materials: DFT calculations and NMR experiments

    NASA Astrophysics Data System (ADS)

    Freitas, Jair C. C.; Scopel, Wanderlã L.; Paz, Wendel S.; Bernardes, Leandro V.; Cunha-Filho, Francisco E.; Speglich, Carlos; Araújo-Moreira, Fernando M.; Pelc, Damjan; Cvitanić, Tonči; Požek, Miroslav

    2015-10-01

    The prospect of carbon-based magnetic materials is of immense fundamental and practical importance, and information on atomic-scale features is required for a better understanding of the mechanisms leading to carbon magnetism. Here we report the first direct detection of the microscopic magnetic field produced at 13C nuclei in a ferromagnetic carbon material by zero-field nuclear magnetic resonance (NMR). Electronic structure calculations carried out in nanosized model systems with different classes of structural defects show a similar range of magnetic field values (18-21 T) for all investigated systems, in agreement with the NMR experiments. Our results are strong evidence of the intrinsic nature of defect-induced magnetism in magnetic carbons and establish the magnitude of the hyperfine magnetic field created in the neighbourhood of the defects that lead to magnetic order in these materials.

  15. Liquid helium-free cryostat and hermetically sealed cryogenic microwave cavity for hyperfine spectroscopy of antiprotonic helium

    PubMed Central

    Massiczek, O.; Friedreich, S.; Juhász, B.; Widmann, E.; Zmeskal, J.

    2011-01-01

    The design and properties of a new cryogenic set-up for laser–microwave–laser hyperfine structure spectroscopy of antiprotonic helium – an experiment performed at the CERN-Antiproton Decelerator (AD), Geneva, Switzerland – are described. Similar experiments for 4He have been performed at the AD for several years. Due to the usage of a liquid helium operated cryostat and therefore necessary refilling of coolants, a loss of up to 10% beamtime occurred. The decision was made to change the cooling system to a closed-circuit cryocooler. New hermetically sealed target cells with minimised 3He gas volume and different dimensions of the microwave resonator for measuring the 3He transitions were needed. A new set-up has been designed and tested at Stefan Meyer Institute in Vienna before being used for the 2009 and 2010 beamtimes at the AD. PMID:22267883

  16. Hyperfine fields at 57Fe in dilute iron-based alloys determined by Mössbauer spectroscopy

    NASA Astrophysics Data System (ADS)

    Idczak, R.; Konieczny, R.; Chojcan, J.

    2015-04-01

    The room temperature Mössbauer spectra of 57Fe were measured for several dilute iron-based alloys, Fe1-xDx (D = Co, Cr, Mn, Mo, Pt, Re, Ta, V, W), annealed at 1270 K for 2 h before the measurements. The analysis of the spectra shows that the effective hyperfine field B at 57Fe nuclei depends on the concentration x of the minority component of the alloys under consideration and the dependence is different for iron nuclei having unlike numbers of impurities in their neighbourhood. The latter is at variance with previously published data, which suggest that the general B(x) dependence is common for all impurity configurations present in the vicinity of iron nuclei.

  17. Re-appraisal of the hyperfine-structure constants in YbF: relativistic configuration interaction approach

    NASA Astrophysics Data System (ADS)

    Naik, Deepali; Sikarwar, Manu; Nayak, Malaya K.; Ghosh, Swapan K.

    2014-11-01

    Ab initio calculation of the spin rotational Hamiltonian parameters A and Ad has been performed using a fully-relativistic restricted active space (RAS) configuration interaction (CI) method for the YbF molecule. These calculations lead to the results for the hyperfine-structure constants as A = 6725 MHz, and Ad = 86 MHz, which agree favorably well with some previous correlated calculations and experimental findings. The convergence behavior of the parameters A and Ad with respect to the size of the active space and basis set has been tested satisfactorily for the reliability of the present results (within an uncertainty of ˜7%). Further, we believe that the theoretical estimates of some symmetry violating interaction constants like Wd can also be predicted with similar accuracy using the RASCI method.

  18. Determination of the hyperfine magnetic field in magnetic carbon-based materials: DFT calculations and NMR experiments.

    PubMed

    Freitas, Jair C C; Scopel, Wanderlã L; Paz, Wendel S; Bernardes, Leandro V; Cunha-Filho, Francisco E; Speglich, Carlos; Araújo-Moreira, Fernando M; Pelc, Damjan; Cvitanić, Tonči; Požek, Miroslav

    2015-01-01

    The prospect of carbon-based magnetic materials is of immense fundamental and practical importance, and information on atomic-scale features is required for a better understanding of the mechanisms leading to carbon magnetism. Here we report the first direct detection of the microscopic magnetic field produced at (13)C nuclei in a ferromagnetic carbon material by zero-field nuclear magnetic resonance (NMR). Electronic structure calculations carried out in nanosized model systems with different classes of structural defects show a similar range of magnetic field values (18-21 T) for all investigated systems, in agreement with the NMR experiments. Our results are strong evidence of the intrinsic nature of defect-induced magnetism in magnetic carbons and establish the magnitude of the hyperfine magnetic field created in the neighbourhood of the defects that lead to magnetic order in these materials. PMID:26434597

  19. Anisotropic hyperfine interactions limit the efficiency of spin-exchange optical pumping of ³He nuclei.

    PubMed

    Tscherbul, T V; Zhang, P; Sadeghpour, H R; Dalgarno, A

    2011-07-01

    We use accurate ab initio and quantum scattering calculations to demonstrate that the maximum ³He spin polarization that can be achieved in spin-exchange collisions with potassium (³⁹K) and silver (¹⁰⁷Ag) atoms is limited by the anisotropic hyperfine interaction. We find that spin exchange in Ag-He collisions occurs much faster than in K-He collisions over a wide range of temperatures (10-600 K). Our analysis indicates that measurements of trap loss rates of ²S atoms in the presence of cold ³He gas may be used to probe anisotropic spin-dependent interactions in atom-He collisions. PMID:21797604

  20. Using bound exciton transitions to optically resolve neutral donor hyperfine states of various donor species in Silicon-28

    NASA Astrophysics Data System (ADS)

    Salvail, Jeff; Dluhy, Phillip; Saeedi, Kamyar; Szech, Michael; Riemann, Helge; Abromisov, Nikolai; Becker, Peter; Pohl, Hans-Joachim; Thewalt, Michael

    2014-03-01

    Phosphorus in silicon is established as a promising resource for use in quantum information processing tasks. The neutral donor hyperfine states have been shown to have record long coherence times, high fidelity gates via RF pulses, and projective readout via optical bound exciton transitions. As Shannon's theory of information tells us, we can process more information in an alphabet of more symbols, so there is motivation to look at donors with higher nuclear spin than the I = 1 / 2 of 31P, which provide access to Hilbert spaces of dimension greater than two. In this talk I will describe optical studies of the donors 75As (I = 3 / 2), 121Sb (I = 5 / 2), and 209Bi (I = 9 / 2) in 28Si.

  1. Steps towards the hyperfine splitting measurement of the muonic hydrogen ground state: pulsed muon beam and detection system characterization

    NASA Astrophysics Data System (ADS)

    Adamczak, A.; Baccolo, G.; Bakalov, D.; Baldazzi, G.; Bertoni, R.; Bonesini, M.; Bonvicini, V.; Campana, R.; Carbone, R.; Cervi, T.; Chignoli, F.; Clemenza, M.; Colace, L.; Curioni, A.; Danailov, M.; Danev, P.; D'Antone, I.; De Bari, A.; De Vecchi, C.; De Vincenzi, M.; Furini, M.; Fuschino, F.; Gadedjisso-Tossou, K. S.; Guffanti, D.; Iaciofano, A.; Ishida, K.; Iugovaz, D.; Labanti, C.; Maggi, V.; Margotti, A.; Marisaldi, M.; Mazza, R.; Meneghini, S.; Menegolli, A.; Mocchiutti, E.; Moretti, M.; Morgante, G.; Nardò, R.; Nastasi, M.; Niemela, J.; Previtali, E.; Ramponi, R.; Rachevski, A.; Rignanese, L. P.; Rossella, M.; Rossi, P. L.; Somma, F.; Stoilov, M.; Stoychev, L.; Tomaselli, A.; Tortora, L.; Vacchi, A.; Vallazza, E.; Zampa, G.; Zuffa, M.

    2016-05-01

    The high precision measurement of the hyperfine splitting of the muonic-hydrogen atom ground state with pulsed and intense muon beam requires careful technological choices both in the construction of a gas target and of the detectors. In June 2014, the pressurized gas target of the FAMU experiment was exposed to the low energy pulsed muon beam at the RIKEN RAL muon facility. The objectives of the test were the characterization of the target, the hodoscope and the X-ray detectors. The apparatus consisted of a beam hodoscope and X-rays detectors made with high purity Germanium and Lanthanum Bromide crystals. In this paper the experimental setup is described and the results of the detector characterization are presented.

  2. Optical coupling

    NASA Astrophysics Data System (ADS)

    Bock, J. J.; Gundersen, J.; Lee, A. T.; Richards, P. L.; Wollack, E.

    2009-03-01

    This paper describes contributions to the CMBpol Technology Study Workshop concerning optical coupling structures. These are structures in or near the focal plane which convert the free space wave to a superconducting microstrip on a SI wafer, or to the waveguide input to a HEMT receiver. In addition to an introduction and conclusions by the editor, this paper includes independent contributions by Bock on 'Planar Antenna-Coupled Bolometers for CMB Polarimetry', by Gunderson and Wollack on 'Millimeter-Wave Platlet Feeds', and by Lee on 'Multi-band Dual-Polarization Lens-coupled Planar Antennas for Bolometric CMB polarimetry.'

  3. (14)N Nuclear Quadrupole Coupling and Methyl Internal Rotation in N-tert-Butylacetamide As Observed by Microwave Spectroscopy.

    PubMed

    Kannengießer, Raphaela; Stahl, Wolfgang; Nguyen, Ha Vinh Lam; Kleiner, Isabelle

    2016-06-16

    The rotational spectrum of N-tert-butylacetamide, CH3(C═O)(NH)C(CH3)3, was measured in the frequency range from 2 to 26.5 GHz using a molecular beam Fourier transform microwave spectrometer. Only one conformer with trans configuration and Cs symmetry was observed. Torsional splittings up to 4.3 GHz occurred in the spectrum due to the internal rotation of the acetyl methyl group CH3(C═O) with a barrier height of approximately 65 cm(-1). Hyperfine structures arise from the quadrupole coupling of the (14)N nucleus appeared for all rotation-torsional transitions. The data set was reproduced with the programs XIAM and BELGI-C1-hyperfine, an extended version of the BELGI-C1 code that includes the effect of the (14)N quadrupole coupling, to root-mean-square deviations of 16.9 and 3.0 kHz, respectively. Quantum chemical calculations were performed to complement the experimental results. The BELGI-C1-hyperfine code was also used to refit the recently published microwave data of N-ethylacetamide to measurement accuracy. PMID:27213507

  4. Electron paramagnetic resonance investigation of photosynthetic reaction centers from Rhodobacter sphaeroides R-26 in which Fe2+ was replaced by Cu2+. Determination of hyperfine interactions and exchange and dipole-dipole interactions between Cu2+ and QA-.

    PubMed Central

    Calvo, R; Passeggi, M C; Isaacson, R A; Okamura, M Y; Feher, G

    1990-01-01

    We report electron paramagnetic resonance (EPR) experiments in frozen solutions of unreduced and reduced photosynthetic reaction centers (RCs) from Rhodobacter sphaeroides R-26 in which Fe2+ has been chemically replaced by the isotope 65Cu2+. Samples in which the primary quinone acceptor QA is unreduced (Cu2+QA:RCs) give a powder EPR spectrum typical for Cu2+ having axial symmetry, corresponding to a d(x2 - y2) ground state orbital, with g values g parallel = 2.314 +/- 0.001 and g perpendicular = 2.060 +/- 0.003. The spectrum shows a hyperfine structure for the nuclear spin of copper (65I = 3/2) with A parallel = (-167 +/- 1) x 10(-4) cm-1 and /A perpendicular/ = (16 +/- 2) x 10(-4) cm-1, and hyperfine couplings with three nitrogen ligands. This has been verified in samples containing the naturally occurring 14N isotope (l = 1), and in samples where the nitrogen ligands to copper were replaced by the isotope 15N (l = 1/2). We introduce a model for the electronic structure at the position of the metal ion which reflects the recently determined three-dimensional structure of the RCs of Rb. sphaeroides (Allen, J. P., G. Feher, T. O. Yeates, H. Komiya, and D. C. Rees. 1987. Proc. Natl. Acad. Sci. USA. 84:5730: Allen, J. P., G. Feher, T. O. Yeates, H. Komiya, and D. C. Rees. 1988. Proc. Natl. Acad. Sci. USA, 85:8487) as well as our EPR results. In this model the copper ion is octahedrally coordinated to three nitrogens from histidine residues and to one carboxylate oxygen from a glutamic acid, forming a distorted square in the plane of the d(x2 = y2) ground state orbital. It is also bound to a nitrogen of another histidine and to the other carboxylate oxygen of the same glutamic acid residue, in a direction approximately normal to this plane. The EPR spectrum changes drastically when the quinone acceptor QA is chemically reduced (Cu2+QA-:RCs); the change is due to the exchange and dipole-dipole interactions between the Cu2+ and QA- spins. A model spin Hamiltonian

  5. Measurements of deuterium quadrupole coupling in propiolic acid and fluorobenzenes using pulsed-beam Fourier transform microwave spectrometers

    SciTech Connect

    Sun, Ming; Sargus, Bryan A.; Carey, Spencer J.; Kukolich, Stephen G.

    2015-04-21

    The pure rotational spectra of deuterated propiolic acids (HCCCOOD and DCCCOOH), 1-fluorobenzene (4-d{sub 1}), and 1,2-difluorobenzene (4-d{sub 1}) in their ground states have been measured using two Fourier transform microwave (FTMW) spectrometers at the University of Arizona. For 1-fluorobenzene (4-d{sub 1}), nine hyperfine lines of three different ΔJ = 0 and 1 transitions were measured to check the synthesis method and resolution. For 1,2-difluorobenzene (4-d{sub 1}), we obtained 44 hyperfine transitions from 1 to 12 GHz, including 14 different ΔJ = 0, 1 transitions. Deuterium quadrupole coupling constants along the three principal inertia axes were well determined. For deuterated propiolic acids, 37 hyperfine lines of Pro-OD and 59 hyperfine lines of Pro-CD, covering 11 and 12 different ΔJ = − 1, 0, 1 transitions, respectively, were obtained from 5 to 16 GHz. Deuterium quadrupole coupling constants along the three inertia axes were well resolved for Pro-OD. For Pro-CD, only eQq{sub aa} was determined due to the near coincidence of the CD bond and the least principal inertia axis. Some measurements were made using a newer FTMW spectrometer employing multiple free induction decays as well as background subtraction. For 1-fluorobenzene (4-d{sub 1}) and 1,2-difluorobenzene (4-d{sub 1}), a very large-cavity (1.2 m mirror dia.) spectrometer yielded very high resolution (2 kHz) spectra.

  6. Prosthesis coupling

    NASA Technical Reports Server (NTRS)

    Reswick, J. B.; Mooney, V.; Bright, C. W.; Owens, L. J. (Inventor)

    1979-01-01

    A coupling for use in an apparatus for connecting a prosthesis to the bone of a stump of an amputated limb is described which permits a bio-compatible carbon sleeve forming a part of the prosthesis connector to float so as to prevent disturbing the skin seal around the carbon sleeve. The coupling includes a flexible member interposed between a socket that is inserted within an intermedullary cavity of the bone and the sleeve. A lock pin is carried by the prosthesis and has a stem portion which is adapted to be coaxially disposed and slideably within the tubular female socket for securing the prosthesis to the stump. The skin around the percutaneous carbon sleeve is able to move as a result of the flexing coupling so as to reduce stresses caused by changes in the stump shape and/or movement between the bone and the flesh portion of the stump.

  7. FLEXIBLE COUPLING

    DOEpatents

    Babelay, E.F.

    1962-02-13

    A flexible shaft coupling for operation at speeds in excess of 14,000 rpm is designed which requires no lubrication. A driving sleeve member and a driven sleeve member are placed in concentric spaced relationship. A torque force is transmitted to the driven member from the driving member through a plurality of nylon balls symmetrically disposed between the spaced sleeves. The balls extend into races and recesses within the respective sleeve members. The sleeve members have a suitable clearance therebetween and the balls have a suitable radial clearance during operation of the coupling to provide a relatively loose coupling. These clearances accommodate for both parallel and/or angular misalignments and avoid metal-tometal contact between the sleeve members during operation. Thus, no lubrication is needed, and a minimum of vibrations is transmitted between the sleeve members. (AEC)

  8. Rotational Spectrum of Dichloromethane-Ne: Internal Dynamics and Cl Quadrupolar Hyperfine Effects.

    PubMed

    Favero, Laura B; Maris, Assimo; Paltrinieri, Laura; Caminati, Walther

    2015-12-10

    The rotational spectra of three isotopologues, CH2(35)Cl2···(20)Ne, CH2(35)Cl(37)Cl···(20)Ne, and CH2(35)Cl2···(22)Ne, of the complex dichloromethane-neon have been assigned and measured by molecular beam Fourier transform microwave spectroscopy. The corresponding tunnelling splittings-due to the motion of Ne from above to below the ClCCl plane-have been determined as ΔE0+0- = 6.8900(5), 6.6630(4), and 6.3724(7) MHz, respectively. From these data the barrier to planarity has been obtained, B2 = 68.7 cm(-1). In addition, the structure and the (35)Cl (or (37)Cl) quadrupole coupling constants have been determined. PMID:26566085

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

    NASA Astrophysics Data System (ADS)

    Sanayei, Ali; Schopohl, Nils

    2016-07-01

    for the hyperfine splitting constant An,j ,0 (HFS ). As an application we consider recent spectroscopic data for the hyperfine splittings of the isotopes 85Rb and 87Rb and find a remarkable agreement with the predicted scaling relation An,j ,0 (HFS )=const .

  10. Blackbody radiation shift, multipole polarizabilities, oscillator strengths, lifetimes, hyperfine constants, and excitation energies in Ca{sup +}

    SciTech Connect

    Safronova, M. S.; Safronova, U. I.

    2011-01-15

    A systematic study of Ca{sup +} atomic properties is carried out using a high-precision relativistic all-order method where all single, double, and partial triple excitations of the Dirac-Fock wave functions are included to all orders of perturbation theory. Reduced matrix elements, oscillator strengths, transition rates, and lifetimes are determined for the levels up to n=7. Recommended values and estimates of their uncertainties are provided for a large number of electric-dipole transitions. Electric-dipole scalar polarizabilities for the 5s, 6s, 7s, 8s, 4p{sub j}, 5p{sub j}, 3d{sub j}, and 4d{sub j} states and tensor polarizabilities for the 4p{sub 3/2}, 5p{sub 3/2}, 3d{sub j}, and 4d{sub j} states in Ca{sup +} are calculated. Methods are developed to accurately treat the contributions from highly excited states, resulting in significant (factor of 3) improvement in the accuracy of the 3d{sub 5/2} static polarizability value, 31.8(3)a{sub 0}{sup 3}, in comparison with the previous calculation [Arora et al., Phys. Rev. A 76, 064501 (2007).]. The blackbody radiation shift of the 4s-3d{sub 5/2} clock transition in Ca{sup +} is calculated to be 0.381(4) Hz at room temperature, T=300 K. Electric-quadrupole 4s-nd and electric-octupole 4s-nf matrix elements are calculated to obtain the ground-state multipole E2 and E3 static polarizabilities. Excitation energies of the ns, np, nd, nf, and ng states with n{<=} 7 in are evaluated and compared with experiment. Recommended values are provided for the 7p{sub 1/2}, 7p{sub 3/2}, 8p{sub 1/2}, and 8p{sub 3/2} removal energies for which experimental measurements are not available. The hyperfine constants A are determined for the low-lying levels up to n=7. The quadratic Stark effect on hyperfine structure levels of {sup 43}Ca{sup +} ground state is investigated. These calculations provide recommended values critically evaluated for their accuracy for a number of Ca{sup +} atomic properties for use in planning and analysis of

  11. Hyperfine structures and Landé g{sub J}-factors for n=2 states in beryllium-, boron-, carbon-, and nitrogen-like ions from relativistic configuration interaction calculations

    SciTech Connect

    Verdebout, S.; Nazé, C.; Rynkun, P.; Godefroid, M.

    2014-09-15

    Energy levels, hyperfine interaction constants, and Landé g{sub J}-factors are reported for n=2 states in beryllium-, boron-, carbon-, and nitrogen-like ions from relativistic configuration interaction calculations. Valence, core–valence, and core–core correlation effects are taken into account through single and double-excitations from multireference expansions to increasing sets of active orbitals. A systematic comparison of the calculated hyperfine interaction constants is made with values from the available literature.

  12. Calculation of vibrational branching ratios and hyperfine structure of 24Mg19F and its suitability for laser cooling and magneto-optical trapping

    NASA Astrophysics Data System (ADS)

    Xu, Liang; Yin, Yanning; Wei, Bin; Xia, Yong; Yin, Jianping

    2016-01-01

    More recently, laser cooling of the diatomic radical magnesium monofluoride (24Mg19F ) is being experimentally preformed [Appl. Phys. Express 8, 092701 (2015), 10.7567/APEX.8.092701 and Opt. Express 22, 28645 (2014), 10.1364/OE.22.028645] and was also studied theoretically [Phys. Rev. A 91, 042511 (2015), 10.1103/PhysRevA.91.042511]. However, some important problems still remain unsolved, so, in our paper, we perform further theoretical study for the feasibility of laser cooling and trapping the 24Mg19F molecule. At first, the highly diagonal Franck-Condon factors of the main transitions are verified by the closed-form approximation, Morse approximation, and Rydberg-Klein-Rees inversion methods, respectively. Afterwards, we investigate the lower X 2Σ1/2 + hyperfine manifolds using a quantum effective Hamiltonian approach and obtain the zero-field hyperfine spectrum with an accuracy of less than 30 kHz ˜5 μ K compared with the experimental results, and then find out that one cooling beam and one or two repumping beams with their first-order sidebands are enough to implement an efficient laser slowing and cooling of 24Mg19F . Meanwhile, we also calculate the accurate hyperfine structure magnetic g factors of the rotational state (X 2Σ1/2 +,N =1 ) and briefly discuss the influence of the external fields on the hyperfine structure of 24Mg19F as well as its possibility of preparing three-dimensional magneto-optical trapping. Finally we give an explanation for the difference between the Stark and Zeeman effects from the perspective of parity and time reversal symmetry. Our study shows that, besides appropriate excitation wavelengths, the short lifetime for the first excited state A 2Π1 /2 , and lighter mass, the 24Mg19F radical could be a good candidate molecule amenable to laser cooling and magneto-optical trapping.

  13. Magnetic properties and hyperfine interactions in Cr8, Cr7Cd, and Cr7Ni molecular rings from 19F-NMR

    SciTech Connect

    Bordonali, L; Garlatti, E; Casadei, C M; Furukawa, Y; Lascialfari, A; Carretta, S; Troiani, F; Timco, G; Winpenny, R E; Borsa, F

    2014-04-14

    A detailed experimental investigation of the 19F nuclear magnetic resonance is made on single crystals of the homometallic Cr₈ antiferromagnetic molecular ring and heterometallic Cr₇Cd and Cr₇ Ni rings in the low temperature ground state. Since the F- ion is located midway between neighboring magnetic metal ions in the ring, the 19F-NMR spectra yield information about the local electronic spin density and ¹⁹F hyperfine interactions. In Cr8, where the ground state is a singlet with total spin S T = 0, the ¹⁹F-NMR spectra at 1.7 K and low external magnetic field display a single narrow line, while when the magnetic field is increased towards the first level crossing field, satellite lines appear in the ¹⁹F-NMR spectrum, indicating a progressive increase in the Boltzmann population of the first excited state S T = 1. In the heterometallic rings, Cr₇Cd and Cr₇ Ni, whose ground state is magnetic with S T = 3/2 and S T = 1/2, respectively, the ¹⁹F-NMR spectrum has a complicated structure which depends on the strength and orientation of the magnetic field, due to both isotropic and anisotropic transferred hyperfine interactions and classical dipolar interactions. From the 19F-NMR spectra in single crystals we estimated the transferred hyperfine constants for both the F⁻-Ni2⁺ and the F⁻-Cd2⁺ bonds. The values of the hyperfine constants compare well to the ones known for F⁻-Ni2⁺ in KNiF₃ and NiF₂ and for F⁻-Cr³⁺ in K₂NaCrF₆. The results are discussed in terms of hybridization of the 2s, 2p orbitals of the F⁻ ion and the d orbitals of the magnetic ion. Finally, we discuss the implications of our results for the electron-spin decoherence.

  14. Hyperfine interaction measurements in LaCrO3 and LaFeO3 perovskites using perturbed angular correlation spectroscopy

    NASA Astrophysics Data System (ADS)

    Dogra, R.; Junqueira, A. C.; Saxena, R. N.; Carbonari, A. W.; Mestnik-Filho, J.; Moralles, M.

    2001-06-01

    The perturbed angular correlation (PAC) technique was used to study the hyperfine interactions in the antiferromagnetic and paramagnetic regions of the distorted perovskites LaCrO3 and LaFeO3. The dilute 111In-->111Cd nuclear probes were introduced into the samples through a chemical process. The present measurements cover the temperature ranges from 15 to 848 K for LaCrO3 and 77 to 1324 K for LaFeO3. Two distinct electric-quadrupole interactions were observed in each compound. The lower quadrupole frequency was assigned to the transition-metal atom site while the higher frequency was attributed to the lanthanum site in both cases. Temperature dependence of the electric-quadrupole interaction parameters indicated structural phase transitions at around 512 and 1223 K, respectively, in LaCrO3 and LaFeO3. The phase transitions were associated with the change from an orthorhombic to rhombohedral structure and characterized by a sudden increase in the electric field gradient Vzz and a decrease in the asymmetry parameter η for both sites. PAC spectra measured below the Néel temperature revealed that at 0 K the supertransferred magnetic hyperfine field on 111Cd at the Cr site in LaCrO3 (2.4 T) is much smaller than at the Fe site in LaFeO3 (19.4 T). The magnetic field on 111Cd at La sites in both compounds is of the order of 0.3 T. Additional measurements were made to determine the magnetic hyperfine field using the probe nucleus 140La-->140Ce. The result reconfirmed that a relatively weak hyperfine field is supertransferred to the probe atoms at La sites.

  15. Charge distribution and hyperfine interactions in the vicinity of impurity sites in In2O3 doped with Fe, Co, and Ni

    NASA Astrophysics Data System (ADS)

    Sena, C.; Costa, M. S.; Muñoz, E. L.; Cabrera-Pasca, G. A.; Pereira, L. F. D.; Mestnik-Filho, J.; Carbonari, A. W.; Coaquira, J. A. H.

    2015-08-01

    In this paper, first-principles calculations based on density functional theory (DFT) were used to determine TM (TM=Fe, Ni, Co) and Cd impurity locations in the In2O3 host structure, their charge states, the electronic and structural relaxations induced in the host lattice as well as to interpret previous and supplementary experimental results of hyperfine interactions. Different techniques were carried out to characterize TM-doped In2O3 bulk samples prepared by the sol-gel method starting from very pure metals. Perturbed angular correlation (PAC) spectroscopy, a sensitive nuclear technique capable of measuring interactions from electronic charge and spins within an atomic distance, was used to experimentally determine hyperfine interactions at cation sites of In2O3 doped with Co and Ni using 111In →111Cd as probe nuclei. Room temperature results of magnetization measurements in In2O3 doped with Fe, Co and Ni show ferromagnetic ordering coexisting with a paramagnetic behavior for all samples. Results of PAC spectroscopy and DFT calculations show that TM atoms locate as second nearest neighbors of Cd probes preferentially occupy symmetric sites of the doped In2O3 crystal structure with lattice parameters slightly different from that of pure In2O3. Moreover, while a major population of 111Cd probes observes almost the same hyperfine interactions measured for pure In2O3, a small population detects magnetic dipole interactions with magnetic hyperfine field at Cd probes of 2.6 T, 3.1 T, and 4.6 T, respectively for Ni, Co, and Fe doping presenting an almost linear dependence on the number of unpaired 3d electrons of the transition metal impurity.

  16. Attempt to measure magnetic hyperfine fields in metallic thin wires under spin Hall conditions using synchrotron-radiation Mössbauer spectroscopy

    SciTech Connect

    Mibu, K. Tanaka, M. A.; Mitsui, T.; Masuda, R.; Kitao, S.; Kobayashi, Y.; Seto, M.; Yoda, Y.

    2015-05-07

    Measurement of the magnetic hyperfine fields in metallic thin wires under spin Hall conditions was attempted using the emerging technique, synchrotron-radiation Mössbauer spectroscopy. A Mössbauer probe layer of {sup 57}Fe (0.2 nm), {sup 57}Fe (0.6 nm), or {sup 119}Sn (0.6 nm) was embedded as an electron spin detector near the surfaces of V, Au, Pt, and {sup 56}Fe wires. The magnitudes of the magnetic hyperfine fields at the {sup 57}Fe and {sup 119}Sn nuclear sites that could be enhanced by non-equilibrium conduction-electron spin polarization were measured both without and with the application of an electric current along the wire. Changes in the Mössbauer spectra were not clearly observed, indicating that the magnetic hyperfine field induced by non-equilibrium spin polarization is smaller than the detection limit at least for the measured systems and conditions.

  17. The impact of quadrupole moment of 4f shell on the hyperfine interactions anisotropy in RAl2 (R=Sm, Tb) intermetallic compounds

    NASA Astrophysics Data System (ADS)

    Delyagin, N. N.; Erzinkyan, A. L.

    2016-03-01

    The magnetic hyperfine interactions for 119Sn impurity atoms in SmAl2 and TbAl2 ferromagnetic compounds have been investigated by Mössbauer spectroscopy technique. These compounds have the same structure but differ in the sign of the quadrupole moment of the R3+ ion. In both cases, the spectrum contains two magnetic subspectra with the ratio of the intensities 1:3, which correspond to a and b Al sites with significantly different hyperfine parameters. The phenomenon change the order the component of inversion component of the Mössbauer spectra was found. This phenomenon is explained by the influence of the quadrupole moment 4f-shell of R3+ ions on the electron density distribution in the valence band. The degree of overlap of electron wave functions being on hybrid orbitals greatly depends on the sign of the 4f-shell quadrupole moment, which gives rise to huge anisotropy in the hyperfine magnetic field and the electric field gradient. Quadrupole deformation induced by the 4f quadrupole moment and the electric field gradient, greatly affects the d-like and p-like components of the electron wave functions, but little effect on the its s-components.

  18. Precise measurements of 203 Tl and 205 Tl excited state hyperfine splittings and isotope shifts using two-step vapor cell spectroscopy

    NASA Astrophysics Data System (ADS)

    Majumder, P. K.; Cheng, Sau Man; Rupasinghe, P. M.

    2016-05-01

    We have undertaken a series of high-precision atomic structure measurement in thallium to test ongoing ab initio atomic structure calculations of relevance to symmetry violation tests in this element. We are currently completing two-step spectroscopy measurements of the 8P1 / 2 and 8P3 / 2 hyperfine structure and isotope shift using a heated thallium vapor cell and two external cavity semiconductor diode lasers. One laser, locked to the thallium 6P1 / 2 --> 7S1 / 2 378 nm transition excites one or both naturally-occurring isotopes to an intermediate state. A second red laser overlaps the UV beam within the thallium vapor cell in both a co-propagating and counter-propagating configuration. Analysis of subsequent Doppler-free absorption spectra of the 7S1 / 2 --> 8P1 / 2 , 3 / 2 visible transitions allows us to extract both hyperfine and isotope shift information for these excited states with uncertainties below 1 MHz. Frequency modulation of the red laser provides convenient in situ frequency calibration. Recent measurements in our group have shown significant discrepancies from older hyperfine structure measurements in thallium excited states. Current results will be presented. Work supported by NSF Grant # 1404206.

  19. Laser-Induced Optical Pumping Measurements of Cross Section for Fine- and Hyperfine-Structure Transitions in Sodium Induced by Collisions with Helium and Argon Atoms

    NASA Technical Reports Server (NTRS)

    Dobson, Chris C.; Sung, C. C.

    1999-01-01

    Optical pumping of the ground states of sodium can radically alter the shape of the laser-induced fluorescence excitation spectrum, complicating measurements of temperature, pressure, etc., which are based on these spectra. Modeling of the fluorescence using rate equations for the eight hyperfine states of the sodium D manifolds can be used to quantify the contribution to the ground state pumping of transitions among the hyperfine excited states induced by collisions with buffer gas atoms. This model is used here to determine, from the shape of experimental spectra, cross sections lor DELTA.F transitions of the P(sub 3/2) state induced by collisions with helium and argon atoms, for a range of values assumed for the P(sub 1/2), DELTA.F cross sections. The hyperfine cross sections measured using this method, which to our knowledge is novel, are compared with cross sections for transitions involving polarized magnetic substates m(sub F) measured previously using polarization sensitive absorption. Also, fine-structure transition cross sections were measured in the pumped vapor, giving agreement with previous measurements made in the absence of pumping.

  20. Laser Induced Optical Pumping Measurements of Cross Sections for Fine and Hyperfine Structure Transitions in Sodium Induced by Collisions with Helium Argon Atoms

    NASA Technical Reports Server (NTRS)

    Dobson, Chris C.; Sung, C. C.

    1998-01-01

    Optical pumping of the ground states of sodium can radically alter the shape of the laser induced fluorescence excitation spectrum, complicating measurements of temperature, pressure, etc., which are based on these spectra. Modeling of the fluorescence using rate equations for the eight hyperfine states of the sodium D manifolds can be used to quantify the contribution to the ground state pumping of transitions among the hyperfine excited states induced by collisions with buffer gas atoms. This model is used here to determine, from the shape of experimental spectra, cross sections for (Delta)F transitions of the P(sub 3/2) state induced by collisions with helium and argon atoms, for a range of values assumed for the P(sub 1/2), (Delta)F cross sections. The hyperfine cross sections measured using this method, which is thought to be novel, are compared with cross sections for transitions involving polarized magnetic substates, m(sub F), measured previously using polarization sensitive absorption. Also, fine structure transition ((Delta)J) cross sections were measured in the pumped vapor, giving agreement with previous measurements made in the absence of pumping.

  1. The TDPAC study of the hyperfine interactions at 111Cd nuclei in RAl 3 compounds synthesized under high pressure

    NASA Astrophysics Data System (ADS)

    Tsvyashchenko, A. V.; Fomicheva, L. N.; Brudanin, V. B.; Kochetov, O. I.; Salamatin, A. V.; Velichkov, A.; Wiertel, M.; Budzynski, M.; Sorokin, A. A.; Ryasny, G. K.; Komissarova, B. A.

    2007-06-01

    The time-differential perturbed angular correlations technique (TDPAC) has been employed for measuring the parameters of hyperfine interactions in earlier known RAl 3 compounds, synthesized at high pressure (8 GPa) and high temperature, where R = La, Ce, Sm, Gd, Tb, Dy, Ho, Er, Yb and Lu. The 111Cd( 111In) radioactive atom was used as a probe nucleus. The X-ray method has revealed that with the increase in the atomic number of a rare-earth element R, the obtained RAl 3 high-pressure phases crystallize, respectively, into orthorhombic, hexagonal and cubic structures. It has been found that in the compounds containing R=La, Ce, Sm and Gd, a deviation from earlier known structural types and the formation of new ones is observed, which is associated with the change of the stoichiometric composition of the said compounds. The results of the PAC measurements have confirmed the deviation from the predetermined stoichiometric composition 1R:3Al for the compounds LaAl 3, CeAl 3, SmAl 3 and GdAl 3 and have verified the RAl 3 stoichiometric structure for the other high-pressure phases obtained in this work.

  2. Hyperfine structure of the 4{f}^{8}5{d}^{2}6s configuration in the Tb atom

    NASA Astrophysics Data System (ADS)

    Furmann, B.; Stefanska, D.; Krzykowski, A.

    2016-01-01

    Within this work new experimental results concerning the hyperfine structure (hfs) in the terbium atom are presented. Hfs constants A and B for eight levels belonging to the even-parity configuration 4{f}85{d}26s were determined, based on the results of measurements performed using the laser-induced fluorescence method in a hollow cathode discharge at 18 spectral lines. The configuration 4{f}85{d}26s in the terbium atom was hitherto very scarcely investigated; for seven of the levels examined within this work results concerning the hfs were obtained for the first time. As a by-product, hfs constants for 12 odd-parity levels, involved as upper levels in the transitions investigated, were also determined. A preliminary attempt at a semi-empirical analysis of Tb I hfs on a multi-configuration basis, based on the results of this work, yielded a value of the one-electron {a}6s10 parameter as well as the respective radial integral {< {r}-3> }6s10, which can be compared with the values along the lanthanide elements series reported in the literature. More conclusive results can certainly be obtained once the experimental database for Tb I becomes more extensive.

  3. NiFe2O4 nanorod: porosity effect on spin canting, quadrupole splitting and hyperfine magnetic properties

    NASA Astrophysics Data System (ADS)

    Mondal, Tuhin S.; Bhattacharjee, Swarupananda; Roychowdhury, Anirban; Majumder, Santanab; Das, Dipankar; Mitra, Manoj K.; Ghosh, Chandan K.

    2015-04-01

    Porous nickel ferrite nanorods having diameter ˜200 nm and length ˜2.5 to 3.0 μm were synthesized by microemulsion method followed by calcination at 450 °C. The morphology and structure of the final as well as intermediate materials, formed during this method, were characterized by x-ray diffraction, field emission scanning electron microscope, high resolution transmission electron microscope and Fourier transform infrared spectroscopy. Positron annihilation spectroscopy was used to identify the structural defects such as vacancies and surface disorder, and to find out the porosity of the synthesized nanorods. Mössbauer spectroscopy was used to determine the cation distribution and magnetic hyperfine property of the nanorods. Detailed magnetic characterization by measuring magnetization as a function of magnetic field and temperature were examined by physical property measurement system and SQUID magnetometer, respectively. The reduced saturation magnetization (Ms = 20.3 emu gm-1) and enhanced coercive (Hc = 37 Oe) field of our synthesized samples was explained on the basis of surface electron effect. Moreover, formation mechanism and effect of precursor materials were also discussed.

  4. Geometrical and electronic structure of fluoro-substituted benzene radical anions based on quantum chemical analysis of hyperfine interactions

    NASA Astrophysics Data System (ADS)

    Shchegoleva, L. N.; Bilkis, I. I.; Schastnev, P. V.

    1983-12-01

    The INDO method has been employed to calculate the isotropic and anisotropic hyperfine interactions for some geometrical structures of the C 6F 6-, C 6HF 5-, 1,2,4,5-F 4C 6H 2- radical anions. The π and σ states of planar radical anions have been considered together with three types of non-planar structures: (a) with out-of-plane distortions of the benzene ring following the "chair" pattern: (b) with neighbouring fluorine atoms displaced in opposite directions from the ring plane due to their electrostatic repulsion: (c) with symmetric (of type) displacement of CF bonds due to the interaction between the ground and lowest excited σ-electron states within the pseudo-Jahn-Teller effect. It is the last model that describes all experimental data on magnetic resonance parameters. This model is also preferable for energy reasons. Most likely, this type of non-planar structures reflects the basic features of the real geometry of the above radical anions whose ground state may be termed as pseudo-π-electronic since the unpaired electron occupies an orbital that is a linear combination of the π and σ orbitals of the corresponding planar structure with a prevailing π component.

  5. Identification of the altered pyrrole in the isomeric sulfmyoglobins: hyperfine shift patterns as indicators of ring saturation in ferric chlorins

    SciTech Connect

    Chatfield, M.J.; La Mar, G.N.; Smith, K.M.; Leung, H.K.; Pandey, R.K.

    1988-03-08

    Analysis of the /sup 1/H NMR hyperfine shift patterns of isomeric sulfmyoglobins is carried out in the met-aquo and met-cyano states to determine the site of saturation in each protein. The utility of the patterns for structure elucidation is established by specific deuterium labeling of heme methyls of the terminal base product. On the basis of the know saturation of ring B in this isomer. The methyl resonance of the saturated ring is found to have strongly attenuated contact shift. Thus, the heme methyl contact shift pattern is diagnostic for the saturated pyrrole in the high-spin state. This rationale is then applied to analyze the assigned NMR spectra of the initial and terminal acid sulfmyoglobin products, revealing that the same ring B is saturated in each isomer. In contrast, the heme methyl contact shift pattern in low-spin ferric complexes reveals that the methyls both on the affected pyrrole and on the trans pyrrole are influenced similarly on sulfmyoglobin formation, precluding the use of this methyl shift pattern as a unique indicator of the site of saturation. Identification of exchangeable proximal histidine resonances for met-aquo sulfmyoglobin complexes with shifts similar to that in native myoglobin dictates inconsequential axial alterations in the sulfmyoglobins, while location of downfield meso proton resonances analogous to those of the native protein demonstrates the retention of the coordinate water in the active site of met-sulfmyoglobin.

  6. Hyperfine local probe study of alkaline-earth manganites SrMnO₃ and BaMnO₃.

    PubMed

    Gonçalves, J N; Amaral, V S; Correia, J G; Lopes, A M L; Araújo, J P; Tavares, P B

    2014-05-28

    We report perturbed angular correlation measurements with (111m)Cd/(111)Cd and (111)In/(111)Cd probes, at the ISOLDE-CERN facility, in the manganite compounds BaMnO3, with the 6H and 15R polymorphs, and SrMnO3, with the 4H polymorph. The electric field gradient (EFG) is measured, and found approximately constant in a large temperature range for all the compounds. The EFG is also calculated from first principles with density functional theory, and compared with experimental results by considering diluted substitutional Cd impurities. Based on the results, we assign as sites for the probes the Ba (for BaMnO3-6H, 15R) and Sr (for SrMnO3-4H) sites, apart from fractions of undetermined origin in the case of BaMnO3-6H. We predict the hyperfine parameters in the recently synthesized multiferroic manganite Sr(0.5)Ba(0.5)MnO3, and its variation with the structure and electric polarization, which is found to be very small. PMID:24787139

  7. Complete hyperfine Paschen-Back regime at relatively small magnetic fields realized in potassium nano-cell

    NASA Astrophysics Data System (ADS)

    Sargsyan, A.; Tonoyan, A.; Hakhumyan, G.; Leroy, C.; Pashayan-Leroy, Y.; Sarkisyan, D.

    2015-04-01

    A one-dimensional nano-metric-thin cell (NC) filled with potassium metal has been built and used to study optical atomic transitions in external magnetic fields. These studies benefit from the remarkable features of the NC allowing one to use λ/2 and λ methods for effective investigations of individual transitions of the K D 1 line. The methods are based on strong narrowing of the absorption spectrum of the atomic column of thickness L equal to λ/2 and to λ (with λ = 770 \\text{nm} being the resonant laser radiation wavelength). In particular, for a π-polarized radiation excitation the λ-method allows us to resolve eight atomic transitions (in two groups of four atomic transitions) and to reveal two remarkable transitions that we call guiding transitions (GT). The probabilities of all other transitions inside the group (as well as the frequency slope vs. magnetic field) tend to the probability and to the slope of GT. Note that for circular polarization there is one group of four transitions and GT do not exist. Among eight transitions there are also two transitions (forbidden for B = 0 ) with the probabilities undergoing strong modification under the influence of magnetic fields. Practically the complete hyperfine Paschen-Back regime is observed at relatively low (∼ 1 \\text{kG}) magnetic fields. Note that for the K D 2 line GT are absent. Theoretical models describe the experiment very well.

  8. Hyperfine interaction and tuning of magnetic anisotropy of Cu doped CoFe2O4 ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Batoo, Khalid Mujasam; Salah, Dina; Kumar, Gagan; Kumar, Arun; Singh, Mahavir; Abd El-sadek, M.; Mir, Feroz Ahmad; Imran, Ahamad; Jameel, Daler Adil

    2016-08-01

    Ferrimagnetic oxides may contain single or multi domain particles which get converted into superparamagnetic state near a critical size. To explore the existence of these particles, we have made Mössbauer and magnetic studies of Cu2+ substitution effect in CoFe2-xO4 Ferrites (0.0, 0.1, 0.2, 0.3, 0.4, and 0.5). All the samples have a cubic spinel structure with lattice parameters increasing linearly with increase in Cu content. The hysteresis loops yield a saturation magnetization, coercive field, and remanent magnetization that vary significantly with Cu content. The magnetic hysteresis curves shows a reduction in saturation magnetization and an increase in coercitivity with Cu2+ ion substitution. The anisotropy constant, K1, is found strongly dependent on the composition of Cu2+ ions. The variation of saturation magnetization with increasing Cu2+ ion content has been explained in the light of Neel's molecular field theory. Mössbauer spectra at room temperature shows two ferrimagnetically relaxed Zeeman sextets. The dependence of Mössbauer parameters such as isomer shift, quadrupole splitting, line width and hyperfine magnetic field on Cu2+ ion concentration have been discussed.

  9. Robust Two-Qubit Gates for Donors in Silicon Controlled by Hyperfine Interactions

    NASA Astrophysics Data System (ADS)

    Kalra, Rachpon; Laucht, Arne; Hill, Charles D.; Morello, Andrea; CentreQuantum Computation; Communication Technology, Australia Team

    2015-03-01

    The electron spin of a single atom in silicon is an excellent candidate for the building-block of a quantum computer. Recent breakthrough experiments have shown an individual phosphorus impurity atom can be used to store and elaborate one bit of quantum information. To continue along this exciting path, it is necessary to couple multiple phosphorus atoms in a controllable way and demonstrate quantum logic operations between pairs of qubits. This was thought to require exquisite control of their mutual interaction, and atomically-precise placement of the spins. Our work shows that the nuclei, to which the electrons are bound, can be exploited to enable a logic operation based on selective resonant excitation. This operation has the enormous advantage that the inter-qubit interaction does not require any modification. Our calculations show that high-fidelity operations can be performed while tolerating a rather wide range of distances between atoms. This drastically reduces the demands posed on device fabrication, paving the way forward for large-scale quantum-information processing in silicon. Funded by the Australian Research Council (CE11E000127) and the U.S. Army Research Office (W911NF-13-1-0024).

  10. Quenching of dynamic nuclear polarization by spin-orbit coupling in GaAs quantum dots.

    PubMed

    Nichol, John M; Harvey, Shannon P; Shulman, Michael D; Pal, Arijeet; Umansky, Vladimir; Rashba, Emmanuel I; Halperin, Bertrand I; Yacoby, Amir

    2015-01-01

    The central-spin problem is a widely studied model of quantum decoherence. Dynamic nuclear polarization occurs in central-spin systems when electronic angular momentum is transferred to nuclear spins and is exploited in quantum information processing for coherent spin manipulation. However, the mechanisms limiting this process remain only partially understood. Here we show that spin-orbit coupling can quench dynamic nuclear polarization in a GaAs quantum dot, because spin conservation is violated in the electron-nuclear system, despite weak spin-orbit coupling in GaAs. Using Landau-Zener sweeps to measure static and dynamic properties of the electron spin-flip probability, we observe that the size of the spin-orbit and hyperfine interactions depends on the magnitude and direction of applied magnetic field. We find that dynamic nuclear polarization is quenched when the spin-orbit contribution exceeds the hyperfine, in agreement with a theoretical model. Our results shed light on the surprisingly strong effect of spin-orbit coupling in central-spin systems. PMID:26184854

  11. Quenching of dynamic nuclear polarization by spin-orbit coupling in GaAs quantum dots

    NASA Astrophysics Data System (ADS)

    Nichol, John M.; Harvey, Shannon P.; Shulman, Michael D.; Pal, Arijeet; Umansky, Vladimir; Rashba, Emmanuel I.; Halperin, Bertrand I.; Yacoby, Amir

    2015-07-01

    The central-spin problem is a widely studied model of quantum decoherence. Dynamic nuclear polarization occurs in central-spin systems when electronic angular momentum is transferred to nuclear spins and is exploited in quantum information processing for coherent spin manipulation. However, the mechanisms limiting this process remain only partially understood. Here we show that spin-orbit coupling can quench dynamic nuclear polarization in a GaAs quantum dot, because spin conservation is violated in the electron-nuclear system, despite weak spin-orbit coupling in GaAs. Using Landau-Zener sweeps to measure static and dynamic properties of the electron spin-flip probability, we observe that the size of the spin-orbit and hyperfine interactions depends on the magnitude and direction of applied magnetic field. We find that dynamic nuclear polarization is quenched when the spin-orbit contribution exceeds the hyperfine, in agreement with a theoretical model. Our results shed light on the surprisingly strong effect of spin-orbit coupling in central-spin systems.

  12. Quenching of dynamic nuclear polarization by spin–orbit coupling in GaAs quantum dots

    PubMed Central

    Nichol, John M.; Harvey, Shannon P.; Shulman, Michael D.; Pal, Arijeet; Umansky, Vladimir; Rashba, Emmanuel I.; Halperin, Bertrand I.; Yacoby, Amir

    2015-01-01

    The central-spin problem is a widely studied model of quantum decoherence. Dynamic nuclear polarization occurs in central-spin systems when electronic angular momentum is transferred to nuclear spins and is exploited in quantum information processing for coherent spin manipulation. However, the mechanisms limiting this process remain only partially understood. Here we show that spin–orbit coupling can quench dynamic nuclear polarization in a GaAs quantum dot, because spin conservation is violated in the electron–nuclear system, despite weak spin–orbit coupling in GaAs. Using Landau–Zener sweeps to measure static and dynamic properties of the electron spin–flip probability, we observe that the size of the spin–orbit and hyperfine interactions depends on the magnitude and direction of applied magnetic field. We find that dynamic nuclear polarization is quenched when the spin–orbit contribution exceeds the hyperfine, in agreement with a theoretical model. Our results shed light on the surprisingly strong effect of spin–orbit coupling in central-spin systems. PMID:26184854

  13. Anomalous Hyperfine Structure of NSF3 in the Degenerate Vibrational State v5=1: Lifting of the Parity Degeneracy by the Fluorine Spin-Rotation Interaction

    NASA Astrophysics Data System (ADS)

    Harder, H.; Macholl, S.; Maeder, H.; Fusina, L.; Ozier, I.

    2010-06-01

    For the principal isotopomer 14N32S19F3 of thiazyl trifluoride in the degenerate fundamental state (v5=1), the hyperfine structure has been investigated in the Q-branch spectrum between 8 and 26.5 GHz using microwave Fourier transform waveguide spectrometers with a resolution limit of ≈ 30 kHz. In addition to l% -type doubling spectra and l-type resonance transitions with (Δ k =% Δ l=± 2), perturbation-allowed spectra were measured with Δ % (k-l) =± 3, ± 6. The range in J was from 13 to 61; for the lower states, kl=-3, -2, -1, 0, +1. For all the transitions, the hyperfine patterns observed are predicted to be doublets when only the nitrogen quadrupole Hamiltonian HQN is taken into account. Doublets were indeed measured for transitions with Γ RV=% A1rightarrow A2, where Γ RV is the rovibrational symmetry. However, when Γ RV=Erightarrow E, triplets and quartets were observed in addition to doublets. These anomalous hyperfine patterns are shown to be due to the (Δ k=± 1) and (Δ k=% ± 2) matrix elements of the fluorine spin-rotation Hamiltonian H% NF characterized by the fluorine spin-rotation constants % c(1)=(cxz+czxast ) and c(2)=(cxx-cyy), respectively. These terms in HNF lift the parity degeneracy for Γ RV=E. The rovibrational Hamiltonian HRV was adopted from an earlier partner study. A good fit to the hyperfine data was obtained with a standard deviation of 3.1 kHz. In the fitting process, 12 rovibrational parameters were varied, while the remaining constants in HRV were left at the values of Ref. (1). In addition, 6 hyperfine parameters were determined: four in HQN, and two in HNF. It was found that \\vert c(1)\\vert =7.48(24) kHz and \\vert c(2)\\vert =2.423(22) kHz. This determination of \\vert c(1)\\vert is the first to be reported based on frequency measurements. The key to the observation of the parity doubling lies in the severe mixing into the eigenvectors of basis vectors with several different values of kl as a result of the clustering1

  14. A Initio Mr-Rci Calculations of ((n - 1)D + Ns)(n) Atomic Bound States: Application to Hyperfine Structure and Electron Affinity Studies.

    NASA Astrophysics Data System (ADS)

    Datta, Debasis

    Systematic inclusion of many-body effects in open d and f subshell atoms has long been known as a formidable challenge in atomic structure theory. Due to the presence of competing relativistic effects in such systems, an appropriate theoretical approach needs to incorporate electron correlation within the framework of the Special Theory of Relativity. To this aim, the Relativistic Configuration Interaction methodology as developed by Beck and others has been extended and applied to multi-reference situations in ((n - 1)d + ns) ^{rm N} type valence configurations. Specific focus has been on the hyperfine structure and electron affinity studies of the transition metal ions and the rare earths respectively. Energies and magnetic dipole and electric quadrupole hyperfine structure constants of all the fifteen Zr II (4d + 5s)^3 J = 0.5, 1.5 levels and the twenty one Nb II (4d + 5s)^4 J = 2 levels have been determined with unprecedented accuracies. The average errors in energy are 0.087 eV and 0.050 eV for Zr II J = 3/2 & 1/2 respectively while that for the ten bottom levels of Nb II J = 2 is 0.055 eV. For the levels known experimentally, the corresponding errors in magnetic dipole hyperfine structure constants are 9.2%, 31.8% and 3.8%. Quite a few of the many-body hyperfine constant values exhibit striking improvements over the Multi-Configurational Dirac Fock values. A new value of nuclear quadrupole moment has also been predicted for Zr II. In all cases certain previous level assignments have been corrected and five previously unknown levels have been identified in Nb II. The rigorous systematics of the many-body effects important for the energy level and hyperfine structure of these systems has been presented including core-valence and core-core effects. Contrary to the conventional wisdom and theoretical predictions of the last decade, the attachment of an f electron has been discarded as the most likely mechanism for the formation of Lanthanide and Actinide negative

  15. Tubular Coupling

    NASA Technical Reports Server (NTRS)

    Rosenbaum, Bernard J. (Inventor)

    2000-01-01

    A system for coupling a vascular overflow graft or cannula to a heart pump. A pump pipe outlet is provided with an external tapered surface which receives the end of a compressible connula. An annular compression ring with a tapered internal bore surface is arranged about the cannula with the tapered internal surface in a facing relationship to the external tapered surface. The angle of inclination of the tapered surfaces is converging such that the spacing between the tapered surfaces decreases from one end of the external tapered surface to the other end thereby providing a clamping action of the tapered surface on a cannula which increases as a function of the length of cannula segment between the tapered surfaces. The annular compression ring is disposed within a tubular locking nut which threadedly couples to the pump and provides a compression force for urging the annular ring onto the cannula between the tapered surfaces. The nut has a threaded connection to the pump body. The threaded coupling to the pump body provides a compression force for the annular ring. The annular ring has an annular enclosure space in which excess cannula material from the compression between the tapered surfaces to "bunch up" in the space and serve as an enlarged annular ring segment to assist holding the cannula in place. The clamped cannula provides a seamless joint connection to the pump pipe outlet where the clamping force is uniformly applied to the cannula because of self alignment of the tapered surfaces. The nut can be easily disconnected to replace the pump if necessary.

  16. Inherent interface defects in thermal (211)Si/SiO{sub 2}:{sup 29}Si hyperfine interaction

    SciTech Connect

    Iacovo, Serena E-mail: andre.stesmans@fys.kuleuven.be; Stesmans, Andre E-mail: andre.stesmans@fys.kuleuven.be

    2014-10-21

    Low temperature electron spin resonance (ESR) studies were carried out on ‘higher index’ (211)Si/SiO{sub 2} interfaces thermally grown in the temperature range T{sub ox} = 400–1066°C. The data reveal the presence of two species of a P{sub b}-type interface defect, exhibiting a significant difference in defect density. On the basis of the pertinent ESR parameters and interface symmetry, the basic defect is typified as P{sub b0}{sup (211)}, close to the Pb0 center observed in standard (100)Si/SiO{sub 2}. The dominant type is found to pertain to defected Si atoms at (111)Si-face terraces with the dangling bond along the [111] direction at ∼19.5°C with the interface normal, these sites thus apparently predominantly accounting for interface mismatch adaptation. The total of the P{sub b}-type defect appearance clearly reflects the higher-index nature of the interface. It is found that T{sub ox} = 750°C is required to minimize the P{sub b0}{sup (211)} defect density through relaxation of the oxide (interface). Q-band ESR saturation spectroscopy reveals an anisotropic {sup 29}Si (nuclear spin I=1/2) hyperfine (hf) doublet associated with the central P{sub b0}{sup (211)} Zeeman signal, with hf parameters closest to those of the similar hf structure of the P{sub b0}{sup (110)} defect in thermal (110)Si/SiO{sub 2}, adducing independent support to the P{sub b0}{sup (211)} typification.

  17. Highly enantioselective oxidative couplings of 2-naphthols catalyzed by chiral bimetallic oxovanadium complexes with either oxygen or air as oxidant.

    PubMed

    Guo, Qi-Xiang; Wu, Zhi-Jun; Luo, Zhi-Bin; Liu, Quan-Zhong; Ye, Jian-Liang; Luo, Shi-Wei; Cun, Lin-Feng; Gong, Liu-Zhu

    2007-11-14

    The chiral bimetallic oxovanadium complexes have been designed for the enantioselective oxidative coupling of 2-naphthols bearing various substituents at C6 and/or C7. The chirality transferring from the amino acid to the axis of the biphenyl in oxovanadium complexes 2 was found to occur with the use of UV and CD spectra and DFT calculation. The homo-coupling reaction with oxygen as the oxidant was promoted by 5 mol % of an oxovanadium complex derived from L-isoleucine and achiral biphenol to afford binaphthols in nearly quantitative yields with high enantioselectivities of up to 98% ee. An oxovanadium complex derived from L-isoleucine and H8-binaphthol is highly efficient at catalyzing the air-oxidized coupling of 2-naphthols with excellent enantioselectivities of up to 97% ee. 51V NMR study shows that the oxovanadium complexes have two vanadium(V) species. Kinetic studies, the cross-coupling reaction, and HRMS spectral studies on the reaction have been carried out and illustrate that two vanadium(V) species are both involved in catalysis and that the coupling reaction undergoes a radical-radical mechanism in an intramolecular manner. Quantum mechanical calculations rationalize the importance of the cooperative effects of the axial chirality matching S-amino acids on the stereocontrol of the oxidative coupling reaction. The application of the transformation in the preparation of chiral ligands and conjugated polymers confirms the importance of the current process in organic synthesis. PMID:17956093

  18. Dark coupling

    SciTech Connect

    Gavela, M.B.; Hernández, D.; Honorez, L. Lopez; Mena, O.; Rigolin, S. E-mail: d.hernandez@uam.es E-mail: omena@ific.uv.es

    2009-07-01

    The two dark sectors of the universe—dark matter and dark energy—may interact with each other. Background and linear density perturbation evolution equations are developed for a generic coupling. We then establish the general conditions necessary to obtain models free from non-adiabatic instabilities. As an application, we consider a viable universe in which the interaction strength is proportional to the dark energy density. The scenario does not exhibit ''phantom crossing'' and is free from instabilities, including early ones. A sizeable interaction strength is compatible with combined WMAP, HST, SN, LSS and H(z) data. Neutrino mass and/or cosmic curvature are allowed to be larger than in non-interacting models. Our analysis sheds light as well on unstable scenarios previously proposed.

  19. Thermoacoustic couple

    DOEpatents

    Wheatley, J.C.; Swift, G.W.; Migliori, A.

    1983-10-04

    An apparatus and method for determining acoustic power density level and its direction in a fluid using a single sensor are disclosed. The preferred embodiment of the apparatus, which is termed a thermoacoustic couple, consists of a stack of thin, spaced apart polymeric plates, selected ones of which include multiple bimetallic thermocouple junctions positioned along opposite end edges thereof. The thermocouple junctions are connected in series in the nature of a thermopile, and are arranged so as to be responsive to small temperature differences between the opposite edges of the plates. The magnitude of the temperature difference, as represented by the magnitude of the electrical potential difference generated by the thermopile, is found to be directly related to the level of acoustic power density in the gas.

  20. Role of spin-orbit coupling in the kinetics of geminal recombination of triplet radical pairs in micelles. Effect of an internal heavy atom

    SciTech Connect

    Levin, P.P.; Kuz'min, V.A.

    1987-07-01

    The authors use radicals from the laser photolysis of benzophenone, bromobenzophenone, 4-phenylphenol, and 4-phenylaniline to study the effect of a heavy atom introduced as a substituent on the recombination kinetics of triplet radical pairs in micelles as a function of the external magnetic field strength. They found that intercombination conversion, which takes place due to the spin-orbit coupling between radicals, makes a significant contribution to the process of singlet-triplet transitions in radical pairs together with the hyperfine interaction. The role of spin-orbit coupling increases significantly when heavy atoms are present in the radicals.

  1. Improved measurement of the hyperfine structure of the laser cooling level 4f^{12}(^3H_6)5d_{5/2}6s^2 (J=9/2) in {}^{169}_{ 69}{{Tm}}

    NASA Astrophysics Data System (ADS)

    Fedorov, S. A.; Vishnyakova, G. A.; Kalganova, E. S.; Sukachev, D. D.; Golovizin, A. A.; Tregubov, D. O.; Khabarova, K. Yu.; Akimov, A. V.; Kolachevsky, N. N.; Sorokin, V. N.

    2015-12-01

    We report on an improved measurement of the hyperfine constant of the 4f^{12}(^3 H_6)5d_{5/2}6s^2 (J=9/2) excited state of {}^{169}_{ 69}{{Tm}} which is involved in the second-stage laser cooling of Tm. To measure the absolute value of the hyperfine splitting interval, we used Doppler-free frequency modulation saturated absorption spectroscopy of Tm atoms in a vapor cell. The sign of the hyperfine constant was determined independently by spectroscopy of laser-cooled Tm atoms. The hyperfine constant of the level was determined to be A_J=-422.112(32) {MHz} from the energy difference between the two hyperfine sublevels, -2110.56(16) {MHz}. In relation to the saturated absorption measurement, we quantitatively treat contributions of various mechanisms to the line broadening and shift. We consider power broadening in the case when Zeeman sublevels of atomic levels are taken into account. We also discuss the line broadening due to frequency modulation and relative intensities of transitions in saturated absorption experiments.

  2. Dynamic hyperfine interactions in 111In(111Cd)-doped ZnO semiconductor: PAC results supported by ab initio calculations

    NASA Astrophysics Data System (ADS)

    Muñoz, Emiliano L.; Mercurio, Marcio E.; Cordeiro, Moacir R.; Pereira, Luciano F. D.; Carbonari, Artur W.; Rentería, Mario

    2012-08-01

    In this work, we present results of Time-Differential γ-γ Perturbed-Angular-Correlations (PAC) experiments performed in 111Cd-doped ZnO semiconductor. The PAC technique has been applied in order to characterize the electric-field-gradient (EFG) tensor at (111In (EC)→) 111Cd nuclei located, as was later demonstrated, at defect-free cation sites of the ZnO host structure. The PAC experiments were performed in the temperature range of 77-1075 K. At first glance, the unexpected presence of low-intensity dynamic hyperfine interactions was observed, which were analyzed with a perturbation factor based on the Bäverstam and Othaz model. The experimental EFG results were compared with ab initio calculations performed with the Full-Potential Augmented Plane Wave plus local orbital (FP-APW+lo) method, in the framework of the Density Functional Theory (DFT), using the Wien2K code. The presence of the dynamic hyperfine interactions has been analyzed enlightened by the FP-APW+lo calculations of the EFG performed as a function of the charge state of the cell. We could correlate the large strength of the dynamic hyperfine interaction with the strong variation of the EFG due to changes in the electronic charge distribution in the Cd vicinity during the time-window of the PAC measurement. It was also revealed that the Cd impurity decays to a final stable neutral charge state (Cd2+) fast enough (in few ns) to produce the nearly undamped observed PAC spectra.

  3. Stark-shift measurement of the {sup 2}S{sub 1/2}, F=3{yields}F=4 hyperfine transition of {sup 133}Cs

    SciTech Connect

    Godone, Aldo; Calonico, Davide; Levi, Filippo; Micalizio, Salvatore; Calosso, Claudio

    2005-06-15

    In this paper we report the measurement of the frequency Stark shift of the ground-state hyperfine transition of {sup 133}Cs observed in a vapor cell through a {lambda} excitation scheme. The measured value of the quadratic Stark coefficient is k=(-2.05{+-}0.04)x10{sup -10} Hz/(V/m){sup 2} when the electric field is perpendicular to the quantization axis. A comparison with the values previously reported in literature is given in view of its interest for the evaluation of the blackbody radiation shift in the primary frequency standards.

  4. Hyperfine structure of {sup 87,89}Sr 5s4d{sup 3}D-5snf transitions in collinear fast beam RIMS

    SciTech Connect

    Bushaw, B. A.; Kluge, H.-J.; Lantzsch, J.; Schwalbach, R.; Schwarz, M.; Stenner, J.; Stevens, H.; Wendt, K.; Zimmer, K.

    1995-04-01

    The title transition, with n=20, 23, and 32 were measured for stable {sup 87}Sr and the observed hfs was interpreted and strong hyperfine mixing of all four terms {sup 1}F3 and {sup 3}F2,3,4 in the upper configuration. The results of the analysis were used to predict the hfs for the radioactive isotope {sup 89}Sr. Measurement were then performed on samples containing 10{sup 9} atoms {sup 89}Sr. The positions and intensities of the hfs components selected for study were found to agree well with the predicted values.

  5. Radiative nonrecoil nuclear finite size corrections of order α(Zα)5 to the hyperfine splitting of S-states in muonic hydrogen

    NASA Astrophysics Data System (ADS)

    Faustov, R. N.; Martynenko, A. P.; Martynenko, G. A.; Sorokin, V. V.

    2014-06-01

    On the basis of quasipotential method in quantum electrodynamics we calculate nuclear finite size radiative corrections of order α(Zα)5 to the hyperfine structure of S-wave energy levels in muonic hydrogen and muonic deuterium. For the construction of the particle interaction operator we employ the projection operators on the particle bound states with definite spins. The calculation is performed in the infrared safe Fried-Yennie gauge. Modern experimental data on the electromagnetic form factors of the proton and deuteron are used.

  6. Strong anomalous temperature dependence of the contact hyperfine contribution to the muon Knight shift in HoB 2C 2

    NASA Astrophysics Data System (ADS)

    De Lorenzi, F.; Gygax, F. N.; Schenck, A.; Tobo, A.; Onodera, H.

    2003-02-01

    Tetragonal HoB 2C 2 is one of the few compounds which show antiferroquadrupolar ordering below the onset of antiferromagnetic order (T Q=4.5 K, T N=5.9 K) . We have started the study of this system with the ultimate aim to learn more about the interaction of the magnetic and quadrupolar degrees of freedom in this context. In the contribution we present results of Knight-shift measurements on a single crystal above TN. The results, firstly, allowed to determine the muon site, which is identified to be the 8i interstitial site, and secondly, revealed an unusual temperature dependence of the contact hyperfine constant Ac.

  7. Lower bound for the variation of the hyperfine populations in the ground state of spin-1 condensates against a magnetic field

    NASA Astrophysics Data System (ADS)

    Xie, W. F.; He, Y. Z.; Bao, C. G.

    2015-10-01

    A simple and analytical expression for the variation of the lower bound and upper bound of the population density ρ0 of hyperfine component μ = 0 particles in the ground state of spin-1 condensates against a magnetic field B has been derived. The lower bound has a distinguished feature, namely, it will tend to the actual ρ0 when B tends to zero and infinite. This feature assures that, in the whole range of B, the lower bound can provide an effective constraint. Numerical examples are given to demonstrate the applicability of the bound.

  8. The Iodine Hvperfine Structure in the Microwave Spectrum of Ethyl Iodide: Nuclear Quadrupole and Spin Rotation Coupling

    NASA Astrophysics Data System (ADS)

    Lee, W. W.; Scherr, Lawrence M.; Barsh, Max K.

    1988-11-01

    Some rotational transitions of ethyl iodide, CH3CH2I, have been reinvestigated by microwave Fourier transform (MWFT) spectroscopy. The iodine hyperfine structure splittings were first ana lyzed using a direct diagonalization procedure of the complete quadrupole Hamiltonian matrix. The results of this analysis showed deviations from our measurements up to 60 kHz. A new analysis using additional spin rotation coupling matrix elements reproduces our measurements within the experi­mental error limit and decreases the standard deviation of the least squares fit from 28 kHz to only 4 kHz.

  9. Matrix elements in the coupled-cluster approach - With application to low-lying states in Li

    NASA Technical Reports Server (NTRS)

    Martensson-Pendrill, Ann-Marie; Ynnerman, Anders

    1990-01-01

    A procedure is suggested for evaluating matrix elements of an operator between wavefunctions in the coupled-cluster form. The use of the exponential ansatz leads to compact exponential expressions also for matrix elements. Algorithms are developed for summing all effects of one-particle clusters and certain chains of two-particle clusters (containing the well-known random-phase approximation as a subset). The treatment of one-particle perturbations in single valence states is investigated in detail. As examples the oscillator strength for the 2s-2p transition in Li as well as the hyperfine structure for the two states are studied and compared to earlier work.

  10. Millimeter-wave spectroscopy and multichannel quantum-defect-theory analysis of high Rydberg states of xenon: The hyperfine structure of {sup 129}Xe{sup +} and {sup 131}Xe{sup +}

    SciTech Connect

    Schaefer, Martin; Raunhardt, Matthias; Merkt, Frederic

    2010-03-15

    Millimeter-wave transitions between high-n Rydberg states of several isotopes of xenon have been recorded at sub-megahertz resolution. The fine and, for {sup 129}Xe and {sup 131}Xe, hyperfine structures of s, p, d, and f Rydberg states with principal quantum number in the range 52{<=}n{<=}64 have been determined from combination differences and analyzed using multichannel quantum defect theory. Improved eigenquantum defects and channel interaction parameters for the odd- and even-parity Rydberg states of xenon and the hyperfine structure of the {sup 2}P{sub 3/2} ground state of {sup 129}Xe{sup +} and {sup 131}Xe{sup +} have been obtained. Nearly degenerate p and d fine or hyperfine levels are very easily mixed by even weak stray electric fields.

  11. Multinuclear magnetic resonance studies of the 2Fe-2S sup * ferredoxin from Anabaena species strain PCC 7120. 3. Detection and characterization of hyperfine-shifted nitrogen-15 and hydrogen-1 resonances of the oxidized form

    SciTech Connect

    Oh, Byung-Ha; Markley, J.L. )

    1990-04-24

    All the nitrogen signals from the amino acid side chains and 80 of the total of 98 backbone nitrogen signals of the oxidized form of the 2Fe{center dot}2S* ferredoxin from Anabaena sp. strain PCC 7120 were assigned by means of a series of heteronuclear two-dimensional experiments. Two additional nitrogen signals were observed in the one-dimensional {sup 15}N NMR spectrum and classified as backbone amide resonances from residues whose proton resonances experience paramagnetic broadening. The one-dimensional {sup 15}N NMR spectrum shows nine resonances that are hyperfine shifted and broadened. From this inventory of diamagnetic nitrogen signals and the available X-ray coordinates of the related ferredoxin, the resolved hyperfine-shifted {sup 15}N peaks were attributed to backbone amide nitrogens of two other amino acids that share electrons with the 2Fe{center dot}2S* center to backbone amide nitrogens of two other amino acids that are close to the 2Fe{center dot}2S* center. The seven {sup 15}N signals that are missing and unaccounted for probably are buried under the envelope of amide signals. {sup 1}H NMR signals from all the amide protons directly bonded to the seven missing and nine hyperfine-shifted nitrogens were too broad to be resolved in conventional 2D NMR spectra. From their dependence on the magnetogyric ratio, a {sup 1}H resonance should be up to 100 times broader than a {sup 15}N resonance that experiences a similar hyperfine interaction. This appears to be the reason why more well-resolved hyperfine-shifted {sup 15}N resonances were observed than corresponding {sup 1}H resonances. The result suggest that hyperfine-shifted {sup 15}N peaks can provide a unique window on the electronic structure and environment of this and other paramagnetic centers.

  12. Estimates of the relative magnitudes of the isotropic and anisotropic magnetic-dipole hyperfine interactions in alkali-metal-noble-gas systems

    NASA Astrophysics Data System (ADS)

    Walter, D. K.; Happer, W.; Walker, T. G.

    1998-11-01

    We present a detailed theoretical analysis of the noble-gas nuclear-spin relaxation due to the anisotropic magnetic-dipole hyperfine interaction between the noble-gas nucleus and alkali-metal valence electron vis à vis the already well-understood (spin-conserving) isotropic magnetic-dipole hyperfine interaction in alkali-metal-noble-gas systems. We find that, for all pairs in which the noble gas is not helium, the predicted spin-relaxation rate from the anisotropic interaction does not exceed 2.5% of the rate from the isotropic interaction, thereby not appreciably limiting the maximum noble-gas nuclear polarization attainable via spin-exchange collisions with polarized alkali-metal atoms. For alkali-metal-helium pairs, we predict that the anisotropic interaction has a slightly larger relative effect, perhaps limiting the nuclear polarization to ~95% of the electronic polarization in the Rb-3He system; however, our confidence in the helium results is limited by a lack of knowledge of the interatomic potentials necessary for the calculation.

  13. Electronic and structural properties, and hyperfine interactions at Sc sites in the semiconductor Sc2O3 : TDPAC and ab initio study

    NASA Astrophysics Data System (ADS)

    Richard, D.; Muñoz, E. L.; Butz, T.; Errico, L. A.; Rentería, M.

    2010-07-01

    The time-differential γ-γ perturbed-angular-correlation (TDPAC) technique using T44i→S44c tracers was applied to study the nuclear quadrupole interaction of the first excited I=1 state of S44c in the cubic bixbyite structure of scandium sesquioxide (Sc2O3) . In addition, ab initio calculations of electronic and structural properties and hyperfine parameters at the cationic sites of the Sc2O3 structure were performed using the full-potential augmented plane wave plus local-orbital (APW+lo) method. The accuracy of the calculations and the excellent agreement of the predicted electric-field-gradient (EFG) tensors and the structural properties (lattice parameters, internal positions) with the experimental results enable us to identify the observed hyperfine interactions and to infer the EFG sign that cannot be measured in conventional TDPAC experiments. Additionally, the APW+lo calculations show that the EFG at Sc sites is originated in the population of Sc3p states and give an explanation for the preferential occupation of the asymmetric cationic site C of the structure by the T44i doping impurities. Finally, the validity of the ionic model, usually used to describe the EFG at native cation sites, is discussed.

  14. Polarized Scattering of Light for Arbitrary Magnetic Fields with Level-crossings from the Combination of Hyperfine and Fine Structure Splittings

    NASA Astrophysics Data System (ADS)

    Sowmya, K.; Nagendra, K. N.; Sampoorna, M.; Stenflo, J. O.

    2015-12-01

    Interference between magnetic substates of the hyperfine structure states belonging to different fine structure states of the same term influences the polarization for some of the diagnostically important lines of the Sun's spectrum, like the sodium and lithium doublets. The polarization signatures of this combined interference contain information on the properties of the solar magnetic fields. Motivated by this, in the present paper, we study the problem of polarized scattering on a two-term atom with hyperfine structure by accounting for the partial redistribution in the photon frequencies arising due to the Doppler motions of the atoms. We consider the scattering atoms to be under the influence of a magnetic field of arbitrary strength and develop a formalism based on the Kramers-Heisenberg approach to calculate the scattering cross section for this process. We explore the rich polarization effects that arise from various level-crossings in the Paschen-Back regime in a single scattering case using the lithium atomic system as a concrete example that is relevant to the Sun.

  15. Structural, magnetic and hyperfine properties of single-phase SrFe12O19 nanoparticles prepared by a sol-gel route

    NASA Astrophysics Data System (ADS)

    Das, A.; Roychowdhury, A.; Pati, S. P.; Bandyopadhyay, S.; Das, D.

    2015-02-01

    Single-phase nanocrystalline strontium hexaferrite (SrFe12O19) powders have been synthesized by a sol-gel method and their structural, magnetic and hyperfine properties are discussed. The optimum annealing temperature of the as-prepared gel for formation of the single-phase SrFe12O19 structure has been found to be 800 °C. X-ray diffraction and Fourier transform infrared studies confirmed formation of the hexaferrite phase. The cation distribution at crystallographic inequivalent sites of the hexaferrite structure has been examined by 57Fe Mössbauer spectroscopy and found to be identical to that reported earlier. Single-phase SrFe12O19 nanoparticles (NPs) showed a magnetic hysteresis loop with high coercivity and saturation magnetization denoting an irreversible magnetization character. The temperature dependent magnetization measurements reveal a difference between the zero-field-cooled and field-cooled curves throughout the measurement range 5-300 K that is attributed to superparamagnetic relaxation of finer hexaferrite particles and disordered spins at the surface of the NPs. Both hyperfine and magnetic studies confirm that magnetic anisotropy plays a crucial role in hexaferrite NPs.

  16. Hyperfine structure and lifetime measurements in the 4s2nd 2D3/2 Rydberg sequence of Ga I by time-resolved laser spectroscopy

    NASA Astrophysics Data System (ADS)

    Liu, Chunqing; Tian, Yanshan; Yu, Qi; Bai, Wanshuang; Wang, Xinghao; Wang, Chong; Dai, Zhenwen

    2016-05-01

    The hyperfine structure (HFS) constants of the 4s2nd 2D3/2 (n=6-18) Rydberg sequence and the 4s26p 2P3/2 level for two isotopes of 69Ga and 71Ga atoms were measured by means of the time-resolved laser-induced fluorescence (TR-LIF) technique and the quantum beat method. The observed hyperfine quantum beat spectra were analyzed and the magnetic-dipole HFS constants A as well as the electric-quadrupole HFS constants B of these levels were obtained by Fourier transform and a program for multiple regression analysis. Also using TR-LIF method radiative lifetimes of the above sequence states were determined at room temperature. The measured lifetime values range from 69 to 2279 ns with uncertainties no more than 10%. To our knowledge, the HFS constants of this Rydberg sequence and the lifetimes of the 4s2nd 2D3/2 (n=10-18) levels are reported for the first time. Good agreement between our results and the previous is achieved.

  17. 29Si attribution of the 1.3 mT hyperfine structure of the E'γ centers in amorphous SiO2

    NASA Astrophysics Data System (ADS)

    Vaccaro, G.; Agnello, S.; Buscarino, G.; Nuccio, L.; Grandi, S.; Mustarelli, P.

    2009-05-01

    We report an experimental investigation by electron paramagnetic resonance of the doublet of lines split by ˜1.3 mT and centered on the E'γ center resonance line in the spectrum of irradiated amorphous SiO2. Commercial and sol-gel materials, some of which subjected to hydrogen-deuterium exchange, were investigated. Exposure to γ or β rays at room temperature of the samples and subsequent thermal treatments were carried out to induce the defects and to study their thermal stability. In all the materials used the ratio between the signal of the E'γ centers and that of the 1.3 mT doublet is constant and independent of the OH and OD contents. Furthermore, the 1.3 mT doublet and the E'γ center feature similar thermal stability. These results support the attribution of the 1.3 mT doublet to the hyperfine interaction between the unpaired electron magnetic moment of the E'γ center and the nuclear magnetic moment of a second near neighboring S29i atom. Our results also suggest that the E'γ site needs an appropriate surrounding of S29i in back-bond configuration to experience this hyperfine interaction.

  18. High-precision, systematic study of hyperfine structure in the 4f/sup N/6s/sup 2/ configuration of the neutral rare earths

    SciTech Connect

    Childs, W.J.; Goodman, L.S.; Pfeufer, V.

    1983-01-01

    Although the hyperfine structure (hfs) of many-electron atoms has been studied intensively in recent years, it is still difficult to distinguish between the competing effects of relativity and configuration interaction. The 4f/sup N/6s/sup 2/ configuration of the neutral rare earths is of particular interest because (a) the low-lying terms are relatively free of configuration interaction, and (b) trends can be examined systematically as one proceeds through the long 4f-shell. The procedure is to deduce, from the measured hfs constants of low levels, the underlying hyperfine radial integrals for comparison with ab initio predictions. Since some of these integrals are extremely sensitive to any configuration interaction and others are not, it is possible to determine both the extent and type of configuration interaction present in some cases. Prior to the start of the present research no precise hfs information existed for the entire second half of the 4f shell of the rare earths. The present measurements were designed both to provide such data and to make possible a systematic study of the hfs throughout the 4f shell. The atomic-beam, laser-rf, double-resonance method was used for the measurements. With this technique, the occurrence of a radiofrequency transition between atomic hfs levels is detected by noting an increase in the laser-induced fluorescence.

  19. Hyperfine field at Mn in the intermetallic compound LaMnSi2 measured by PAC using 111Cd nuclear probe

    NASA Astrophysics Data System (ADS)

    Domienikan, C.; Bosch-Santos, B.; Cabrera Pasca, G. A.; Saxena, R. N.; Carbonari, A. W.

    2015-04-01

    Magnetic hyperfine field at Mn site has been measured in the orthorhombic intermetallic compound LaMnSi2 with PAC spectroscopy using radioactive 111In- 111Cd nuclear probe. Samples of LaMnSi2 were prepared by melting pure metallic components in stoichiometric proportion in an arc furnace under argon atmosphere. The samples were sealed in a quartz tube under helium atmosphere, annealed at 1000 °C for 60 h and quenched in water. Samples were analyzed with X-ray diffraction method. 111In was introduced in the samples by thermal diffusion at 1000 °C for 60 h. PAC measurements were carried out with a six BaF2 detector spectrometer at several temperatures between 50 K and 410 K. Results show well defined quadrupole and magnetic interactions at all temperatures. The magnetic hyperfine field (Bhf) measured at 50 K is 7.1(1) T. The temperature dependence of Bhf follows the normal Brillouin-like behavior expected for a simple ferromagnetic ordering. The ferromagnetic transition temperature (Tc) was determined to be 401(1) K.

  20. Assignment of selected hyperfine proton NMR resonances in the met forms of Glycera dibranchiata monomer hemoglobins and comparisons with sperm whale metmyoglobin

    SciTech Connect

    Constantinidis, I.; Satterlee, J.D.; Pandey, R.K.; Leung, H.K.; Smith, K.M.

    1988-04-19

    This work indicates a high degree of purity for our preparations of all three of the primary Glycera dibranchiata monomer hemoglobins and details assignments of the heme methyl and vinyl protons in the hyperfine shift region of the ferric (aquo.) protein forms. The assignments were carried out by reconstituting the apoproteins of each component with selectively deuteriated hemes. The results indicate that even though the individual component preparations consist of essentially a single protein, the proton NMR spectra indicate spectroscopic heterogeneity. Evidence is presented for identification and classification of major and minor protein forms that are present in solutions of each component. Finally, in contrast to previous results, a detailed analysis of the proton hyperfine shift patterns of the major and minor forms of each component, in comparison to the major and minor forms of metmyoglobin, leads to the conclusions that the corresponding forms of the proteins from each species have strikingly similar heme-globin contacts and display nearly identical heme electronic structures and coordination numbers.

  1. Anomalous hyperfine structure of NSF3 in the degenerate vibrational state v5=1: Lifting of the parity degeneracy by the fluorine spin-rotation interaction

    NASA Astrophysics Data System (ADS)

    Harder, Hauke; Macholl, Sven; Mäder, Heinrich; Fusina, Luciano; Ozier, Irving

    2010-03-01

    For the principal isotopologue N14S32F193 of thiazyl trifluoride in the degenerate fundamental state (v5=1), the hyperfine structure has been investigated in the Q-branch spectrum between 8 and 26.5 GHz using microwave Fourier transform waveguide spectrometers with a resolution limit of ≈30 kHz. In addition to l-type doubling spectra and l-type resonance transitions with (Δk=Δl=±2), perturbation-allowed spectra were measured with Δ(k-l)=±3,±6. The range in J was from 13 to 61; for the lower states, kl=-3,-2,-1,0,+1. For all the transitions, the hyperfine patterns observed are predicted to be doublets when only the nitrogen quadrupole Hamiltonian HQN is taken into account. Doublets were indeed measured for transitions with ΓRV=A1↔A2, where ΓRV is the rovibrational symmetry. However, when ΓRV=E↔E, triplets and quartets were observed in addition to doublets. These anomalous hyperfine patterns are shown to be due to the (Δk=±1) and (Δk=±2) matrix elements of the fluorine spin-rotation Hamiltonian HSRF characterized by the fluorine spin-rotation constants c(1)=(1)/(2)(cxz+czx*) and c(2)=(1)/(2)(cxx-cyy), respectively. These terms in HSRF lift the parity degeneracy for ΓRV=E. The rovibrational Hamiltonian HRV was adopted from an earlier partner study [S. Macholl , J. Phys. Chem. A 113, 668 (2009)]. A good fit to the hyperfine data was obtained with a standard deviation of 3.1 kHz. In the fitting process, 12 rovibrational parameters were varied, while the remaining constants in HRV were left at the values of Macholl In addition, six hyperfine parameters were determined: four in HQN, and two in HSRF. It was found that |c(1)|=7.48(24) kHz and |c(2)|=2.423(22) kHz. This determination of c(1) is the first to be reported based on frequency measurements. In all the previous detections of parity doubling where the splittings were accounted for quantitatively, the levels involved had K=|k|=1 in studies of the ground vibrational state or G≡|k-l|=1 in

  2. Topological Nodal-Line Superfluid in Spin-Orbit Coupled Cold Atomic Systems

    NASA Astrophysics Data System (ADS)

    He, Wen-Yu; Xu, Dong-Hui; Zhou, Tong; Law, K. T.; Hong Kong University of Science; Technology Collaboration

    Topological nodal line superconductivity or superfluidity is a fascinating topological gapless phase which hosts bulk Weyl ring degeneracy in the quasiparticle excitation spectrum and supports Majorana zero bound modes with a large density of states at the edge. In this work, based on the experimental realized 1D spin orbit coupling, we show the emergence of topological nodal line superfluid phase in Fermionic atoms trapped in 3D cubic optical lattice when the s wave pairing field is introduced through Feshbach resonance between the two atomic hyperfine spin states. The nodal line degeneracy is further found to evolve into Weyl nodes once another component of spin orbit coupling field enters to break the chiral symmetry. The momentum resolved radio frequency spectroscopy is suggested to manifest the topological nodal line superfluid phase.

  3. Microwave measurements of cobalt and nitrogen quadrupole coupling in Co(CO)3NO

    NASA Astrophysics Data System (ADS)

    Kukolich, S. G.; Roehrig, M. A.; Haubrich, S. T.; Shea, J. A.

    1991-01-01

    J=2→3, 3→4, 4→5, and 5→6 transitions in the oblate symmetric top molecule cobalt tricarbonyl nitrosyl were measured using a Flygare-Balle type pulsed beam microwave spectrometer. K=0 and K=3 transitions were observed for J=3→4 and 4→5. Hyperfine structure due to 59Co and 14N nuclear quadrupole coupling interactions was well resolved. The measured quadrupole coupling strengths are eQqcc (59Co)=35.14(30) MHz and eQqcc (14N)=-1.59(10). Measured rotation and distortion constants are B0=1042.1590(4) MHz and Dj =0.17(8) kHz. The measured B value is 4% smaller than the B value calculated from electron diffraction data. Spin-rotation and a quadrupole distortion term were also obtained for 59Co.

  4. Experimental investigation of the hyperfine spectra of Pr I-lines: Discovery of new fine structure levels with high angular momentum

    NASA Astrophysics Data System (ADS)

    Siddiqui, Imran; Khan, Shamim; Windholz, Laurentius

    2014-05-01

    We present 66 even and 58 odd parity newly discovered fine structure levels of Pr I with high angular momentum: J = 15/2, 17/2 and 19/2 and 21/2. Spectral lines in the range 4200 Å to 7500 Å were experimentally investigated using laser induced fluorescence spectroscopy in a hollow cathode discharge lamp. The levels were discovered by analysis of the recorded hyperfine patterns of the investigated transitions. More than 800 spectral lines could be classified with help of these levels. Supplementary material in the form of one pdf file available from the Journal web page at http://dx.doi.org/10.1140/epjd/e2014-50025-7

  5. Precision Measurement of the Hyperfine Structure of Laser-Cooled Radioactive {sup 7}Be{sup +} Ions Produced by Projectile Fragmentation

    SciTech Connect

    Okada, K.; Wada, M.; Nakamura, T.; Takamine, A.; Schury, P.; Ishida, Y.; Sonoda, T.; Kanai, Y.; Kojima, T. M.; Lioubimov, V.; Ogawa, M.; Yamazaki, Y.; Yoshida, A.; Kubo, T.; Katayama, I.; Ohtani, S.; Wollnik, H.; Schuessler, H. A.

    2008-11-21

    The ground state hyperfine splitting of {sup 7}Be{sup +} has been measured by laser-microwave double-resonance spectroscopy in the online rf trap of RIKEN's slow RI-beam facility. Be ions produced by projectile fragmentation of {sup 13}C at {approx_equal}1 GeV were thermalized in a rf ion guide gas cell and subsequently laser cooled in the ion trap to {approx_equal}1 {mu}eV. This 10{sup 15}-fold reduction of the kinetic energy allows precision spectroscopy of these ions. A magnetic hfs constant of A=-742.772 28(43) MHz was measured for {sup 7}Be{sup +}, from which a nuclear magnetic moment of {mu}{sub I}=-1.399 28(2){mu}{sub N} was deduced.

  6. Hyperfine, rotational, and Zeeman structure of the lowest vibrational levels of the {sup 87}Rb{sub 2} (1) {sup 3{Sigma}}{sub g}{sup +} state

    SciTech Connect

    Takekoshi, T.; Lang, F.; Strauss, C.; Denschlag, J. Hecker; Lysebo, Marius; Veseth, Leif

    2011-06-15

    We present the results of an experimental and theoretical study of the electronically excited (1){sup 3{Sigma}}{sub g}{sup +} state of {sup 87}Rb{sub 2} molecules. The vibrational energies are measured for deeply bound states from the bottom up to v{sup '}=15 using laser spectroscopy of ultracold Rb{sub 2} Feshbach molecules. The spectrum of each vibrational state is dominated by a 47-GHz splitting into 0{sub g}{sup -} and 1{sub g} components caused mainly by a strong second-order spin-orbit interaction. Our spectroscopy fully resolves the rotational, hyperfine, and Zeeman structure of the spectrum. We are able to describe this structure to the first order using a simplified effective Hamiltonian.

  7. Hyperfine structure of high-L states in 143,145i by atomic-beam laser-rf double resonance

    NASA Astrophysics Data System (ADS)

    Childs, W. J.

    1991-07-01

    The atomic-beam laser-rf double-resonance technique has been used to study the hyperfine structure (hfs) of the metastable 7L5-11 and 7K4 states of the 4f45d6s configuration in 143,145i. Four zero-field intervals were measured in each state and the results used to assign the conventional hfs constants A and B. Comparison of the results with predictions of the Sandars-Beck model allowed evaluation of the relevant single-electron radial hfs integrals. These are compared with earlier results from the Nd i atomic ground term and with extrapolations from other rare-earth elements. The unusually large orbital-angular-momentum values (L=7 and 8 for the states studied) do not appear to have introduced any anomalous effects. Ab initio calculations are not yet feasible for the complex 4f45d6s levels studied.

  8. Hyperfine structure constants and isotope shift of the levels of the configuration 4 f 6 5 d 6 s 2 in Eu I

    NASA Astrophysics Data System (ADS)

    Elantkowska, M.; Bernard, A.; Dembczyński, J.; Ruczkowski, J.

    1993-06-01

    The hyperfine structure (hfs) and the isotope shift (IS) of transitions between metastable levels of the configuration 4 f 7 5 d 6 s and levels of the configuration 4 f 6 5 d 6 s 2 of151Eu and153Eu were studied by means of the high resolution laser-atomic-beam technique. New data for the hfs in151Eu and153Eu were obtained as well as new and more accurate for the IS between151Eu and153Eu. The measured hfs constants A and B of the 4 f 6 5 d 6 s 2 configuration allow to perform a parametric analysis using the Sandars and Beck theory. The value of the Sternheimer correction is also disscused.

  9. Hyperfine structure of the (5d+6s)3 configuration of 139 i: New measurements and ab initio multiconfigurational Dirac-Fock calculations

    NASA Astrophysics Data System (ADS)

    Childs, W. J.; Nielsen, U.

    1988-01-01

    The atomic-beam laser-rf double-resonance method has been used to measure precisely the dipole and quadrupole hyperfine structure (hfs) of 11 levels of the 5d26s configuration and four levels of the 5d3 configuration of 139La i. The results, together with earlier results for lower-lying levels, are compared in detail with new multiconfiguration Dirac-Fock (MCDF) ab initio calculations. The agreement is good to fair overall, but is poor in some areas. The comparison yields new insights and suggests areas in which the theoretical approach must be improved. In particular, the theory underestimates the importance of contact hfs in the 5d26s configuration by 25-40 %. In addition, there is at present no self-consistent way in the MCDF approach to take account of the large core polarization observed in the 5d3 4F term.

  10. Energy, fine structure, hyperfine structure, and radiative transition rates of the high-lying multi-excited states for B-like neon

    NASA Astrophysics Data System (ADS)

    Zhang, Chun Mei; Chen, Chao; Sun, Yan; Gou, Bing Cong; Shao, Bin

    2015-04-01

    The Rayleigh-Ritz variational method with multiconfiguration interaction wave functions is used to obtain the energies of high-lying multi-excited quartet states 1 s 22 s2 pnl and 1 s 22 p 2 nl 4Pe,o ( n ≥ 2) in B-like neon, including the mass polarization and relativistic corrections. The fine structure and hyperfine structure of the excited quartet states for this system are investigated. Configuration structures of the high-lying multi-excited series are further identified by relativistic corrections and fine structure splittings. The transition rates and wavelengths are also calculated. Calculated wavelengths include the quantum electrodynamic effects. The results are compared with other theoretical and experimental data in the literature.

  11. Rotational and hyperfine analysis of the E2Π1/2-X2Δ3/2 electronic transition of TaO

    NASA Astrophysics Data System (ADS)

    Christopher, Casey R.; Lee, Stephanie Y.; Gwandu, Francis B.; Matsumoto, Andrew J.; Knurr, Benjamin J.; Mahle, Thomas K.; Morrow, Zachary W.; Varberg, Thomas D.

    2014-07-01

    We have recorded the E2Π1/2-X2Δ3/2 (0, 0) and (1, 0) bands of TaO at sub-Doppler resolution by intermodulated fluorescence spectroscopy. The data were fitted using a Hamiltonian expressed in a Hund's case (c) basis set, leading to accurate values for the rotational, lambda-doubling and hyperfine constants of the upper state, which could be definitively assigned as 2Π1/2 for the first time. The E2Π1/2 state has an energy of T0 = 15876.5764(2) cm-1 and a vibrational interval of ΔG1/2 = 925.3164(3) cm-1.

  12. Silicon quantum processor with robust long-distance qubit coupling

    NASA Astrophysics Data System (ADS)

    Tosi, Guilherme; Mohiyaddin, Fahd A.; Tenberg, Stefanie; Rahman, Rajib; Klimeck, Gerhard; Morello, Andrea

    Recent demonstration of high-fidelity quantum operations using donors in silicon has ignited an urge in scaling up these systems to a multi-qubit device. However, multi-qubit operations and long-distance donor coupling remain a formidable challenge. We will present a novel scalable design for a silicon quantum processor that allows for long-distance fast 2-qubit gates and does not require precise donor placement. Quantum information is encoded into either the nuclear-spin or the flip-flop states of electron and nucleus. It can be manipulated by biasing the electron wavefunction to be shared between donor and interface, in such a way that the hyperfine interaction strongly depends on electric fields. The qubits are spaced by hundreds of nanometers and coupled through direct electric dipole interactions and/or photonic links. All operations are performed at second-order clock transitions, preserving the qubits' outstanding coherence times. A large number of qubits can then be interconnected in a network robust against errors. Prototypical devices are fabricated to demonstrate the processor's basic units

  13. The magnetic behavior of the intermetallic compound NdMn{sub 2}Ge{sub 2} studied by magnetization and hyperfine interactions measurements

    SciTech Connect

    Bosch-Santos, B. Carbonari, A. W.; Cabrera-Pasca, G. A.; Saxena, R. N.; Freitas, R. S.

    2015-05-07

    The magnetic behavior of the intermetallic compound NdMn{sub 2}Ge{sub 2} was investigated by bulk magnetization measurements and measurements of hyperfine interactions using perturbed γ–γ angular correlation (PAC) spectroscopy. Magnetization measurements indicate the presence of four magnetic transitions associated with the Mn and Nd magnetic sublattices. At high temperatures, magnetic measurements show a change in the slope of the magnetization due to an antiferromagnetic transition around T{sub N} ∼ 425 K and a well defined ferromagnetic transition at T{sub C} ∼ 320 K. Moreover, at ∼210 K a peak is observed in the magnetization curve, which is assigned to the reorientation of the Mn spin, and at ∼25 K an increase in the magnetic moment is also observed, which is ascribed to the ordering of Nd ions. PAC measurements using {sup 140}La({sup 140}Ce) and {sup 111}In({sup 111}Cd) probe nuclei allowed the determination of the temperature dependence of the magnetic hyperfine field (B{sub hf}) at Nd and Mn sites, respectively. PAC results with {sup 111}Cd probe nuclei at Mn sites show that the dependence of B{sub hf} with temperature follows the expected behavior for the host magnetization associated with the magnetic ordering of Mn ions. From these results, the antiferromagnetic transition followed by a ferromagnetic ordering is clearly observed. PAC results with {sup 140}Ce probe nuclei at Nd sites, however, showed a strong deviation from the Brillouin function, which is attributed to the Ce 4f-electron contribution to B{sub hf}.

  14. Detection and characterization of hyperfine-shifted resonances in the proton nuclear magnetic resonance spectrum of Anabaena 7120 ferredoxin at high magnetic fields.

    PubMed

    Skjeldal, L; Westler, W M; Markley, J L

    1990-05-01

    This paper presents previously unobserved signals in the 1H NMR spectra of oxidized and reduced [2Fe-2S]-ferredoxin from Anabaena 7120 detected at 400, 500, and 600 MHz. The signals shifted to low field exhibited longitudinal relaxation (T1) values in the range of 100-400 microseconds and line widths in the range of 1-10 kHz (at 400 MHz), and the chemical shifts of all signals showed strong temperature dependence. Although the line widths were smaller at lower magnetic fields, the resolution was better at higher magnetic fields. In the oxidized state, a broad signal was detected at 37 ppm, which corresponds to at least 6 protons, and whose chemical shift exhibits positive temperature dependence. This signal also was found in oxidized ferredoxin reconstituted in 2H2O, which excludes the signal as arising from solvent-exchangeable amide protons. In the reduced state, four signals detected between 90 and 140 ppm exhibited negative temperature dependence. These consisted of two pairs of signals, each pair having one component with half the linewidth of the other. On the basis of their chemical shifts, linewidths, longitudinal relaxation properties, and temperature dependence we assigned these resonances to four of the beta hydrogens of the ligated cysteines. Two solvent-exchangeable hyperfine-shifted signals were found in the reduced state; these are located upfield of the diamagnetic region. The low-field hyperfine resonances of half-reduced ferredoxin in the presence of sodium dithionite showed a self electron transfer exchange rate that was slow on the NMR scale as observed earlier (Chan, T., and Markley, J. L. (1983) Biochemistry 22, 5982-5987), but the exchange rate was accelerated in the presence of methyl viologen. PMID:2327800

  15. 1H nuclear-magnetic-resonance investigation of oxidized Fe4S4 ferredoxin from Thermotoga maritima. Hyperfine-shifted resonances, sequence-specific assignments and secondary structure.

    PubMed

    Wildegger, G; Bentrop, D; Ejchart, A; Alber, M; Hage, A; Sterner, R; Rösch, P

    1995-05-01

    The oxidized Fe4S4 ferredoxin from the hyperthermophilic bacterium Thermotoga maritima has been investigated by one- and two-dimensional NMR in order to characterize its hyperfine-shifted resonances originating from the cysteinyl cluster ligands and to assign its resonances in the diamagnetic shift range. The chemical shift and relaxation time pattern of the hyperfine-shifted signals is very similar to other oxidized Fe4S4 ferredoxins. A tentative sequence-specific assignment of these resonances according to a general pattern of chemical shift of cysteine protons versus sequence position of cluster ligand is presented. Furthermore, sequence-specific assignments for 85% of the amino acid residues that were obtained without any guidance by known X-ray structures of ferredoxins are given. They reveal the formation of at least two elements of secondary structure by the polypeptide chain of T. maritima ferredoxin: an alpha-helix comprising residues C43-D49 and a double-stranded antiparallel beta-sheet consisting of the N- and C-terminal parts of the protein. This folding pattern is very similar to that of the crystallographically characterized ferredoxin from the mesophile Desulfovibrio gigas [Kissinger, C.R., Sieker, L.C., Adman E.T. & Jensen, L.H. (1991) J. Mol. Biol. 219, 693-715] and therefore suggesting different mechanisms of stabilization for T. maritima ferredoxin and the ferredoxin from the hyperthermophilic archaeon Pyrococcus furiosus that was recently investigated by NMR [Teng, Q., Zhou, Z.H., Smith, E.T., Busse, S. C., Howard, J.B., Adams M.W.W. & La Mar, G.N. (1994) Biochemistry 33, 6316-6326]. PMID:7758460

  16. Magnetic hyperfine structure of the ground-state doublet in highly charged ions 89+,87+229Th and the Bohr-Weisskopf effect

    NASA Astrophysics Data System (ADS)

    Tkalya, E. V.; Nikolaev, A. V.

    2016-07-01

    Background: The search for new opportunities to investigate the low-energy level in the 229Th nucleus, which is nowadays intensively studied experimentally, has motivated us to theoretical studies of the magnetic hyperfine (MHF) structure of the 5 /2+ (0.0 eV) ground state and the low-lying 3 /2+ (7.8 eV) isomeric state in highly charged 89+229Th and 87+229Th ions. Purpose: The aim is to calculate, with the maximal precision presently achievable, the energy of levels of the hyperfine structure of the 229Th ground-state doublet in highly charged ions and the probability of radiative transitions between these levels. Methods: The distribution of the nuclear magnetization (the Bohr-Weisskopf effect) is accounted for in the framework of the collective nuclear model with Nilsson model wave functions for the unpaired neutron. Numerical calculations using precise atomic density functional theory methods, with full account of the electron self-consistent field, have been performed for the electron structure inside and outside the nuclear region. Results: The deviations of the MHF structure for the ground and isomeric states from their values in a model of a pointlike nuclear magnetic dipole are calculated. The influence of the mixing of the states with the same quantum number F on the energy of sublevels is studied. Taking into account the mixing of states, the probabilities of the transitions between the components of the MHF structure are calculated. Conclusions: Our findings are relevant for experiments with highly ionized 229Th ions in a storage ring at an accelerator facility.

  17. Spin structure of harmonically trapped one-dimensional atoms with spin-orbit coupling

    NASA Astrophysics Data System (ADS)

    Guan, Q.; Blume, D.

    2015-08-01

    We introduce a theoretical approach to determine the spin structure of harmonically trapped atoms with two-body zero-range interactions subject to an equal mixture of Rashba and Dresselhaus spin-orbit coupling created through Raman coupling of atomic hyperfine states. The spin structure of bosonic and fermionic two-particle systems with finite and infinite two-body interaction strength g is calculated. Taking advantage of the fact that the N -boson and N -fermion systems with infinitely large coupling strength g are analytically solvable for vanishing spin-orbit coupling strength kso and vanishing Raman coupling strength Ω , we develop an effective spin model that is accurate to second order in Ω for any kso and infinite g . The three- and four-particle systems are considered explicitly. It is shown that the effective spin Hamiltonian, which contains a Heisenberg exchange term and an anisotropic Dzyaloshinskii-Moriya exchange term, describes the transitions that these systems undergo with the change of kso as a competition between independent spin dynamics and nearest-neighbor spin interactions.

  18. Experimental realization of two-dimensional synthetic spin-orbit coupling in ultracold Fermi gases

    NASA Astrophysics Data System (ADS)

    Huang, Lianghui; Meng, Zengming; Wang, Pengjun; Peng, Peng; Zhang, Shao-Liang; Chen, Liangchao; Li, Donghao; Zhou, Qi; Zhang, Jing

    2016-06-01

    Spin-orbit coupling (SOC) is central to many physical phenomena, including fine structures of atomic spectra and topological phases in ultracold atoms. Whereas, in general, SOC is fixed in a system, laser-atom interaction provides a means to create and control synthetic SOC in ultracold atoms. Despite significant experimental progress in this area, two-dimensional (2D) synthetic SOC, which is crucial for exploring two- and three-dimensional topological phases, is lacking. Here, we report the experimental realization of 2D SOC in ultracold 40K Fermi gases using three lasers, each of which dresses one atomic hyperfine spin state. Through spin-injection radiofrequency (rf) spectroscopy, we probe the spin-resolved energy dispersions of the dressed atoms, and observe a highly controllable Dirac point created by the 2D SOC. These results constitute a step towards the realization of new topological states of matter.

  19. Full Controllability of a Singlet-Triplet Qubit Coupled to a Nuclear Spin Qubit

    NASA Astrophysics Data System (ADS)

    Baczewski, Andrew D.; Gamble, John King; Jacobson, N. Tobias; Muller, Richard P.; Nielsen, Erik; Carr, Stephen M.; Carroll, Malcolm S.; Curry, Matthew; Harvey-Collard, Patrick; Jock, Ryan M.; Rudolph, Martin

    Recent experimental developments indicate that it is possible to drive coherent singlet-triplet rotations in a MOS quantum dot coupled to a single nearby phosphorus donor through the electron-nucleus hyperfine interaction. With the addition of NMR, we propose that it is possible to achieve universal 2-qubit control spanning i.) an electronic singlet-triplet subspace of the dot, ii.) the spin-1/2 donor nucleus, and iii.) entangling operations between them. We will assess the practicality of such an approach given realistic experimental conditions and constraints, including a comparison of pulsed and RF control of the detuning between the donor and dot. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Security Administration under Contract DE-AC04-94AL85000.

  20. Biorhythm in Couple Counseling

    ERIC Educational Resources Information Center

    Araoz, Daniel L.

    1977-01-01

    Twelve couples in marital counseling were studied during 12 months on the basis of their biorhythms. For each couple a compatibility percentage was obtained. It was found that difficulties in their interaction correlated highly with dissonance in their biorhythms. (Author)

  1. The magnetic transition in ε-Fe{sub 2}O{sub 3} nanoparticles: Magnetic properties and hyperfine interactions from Mössbauer spectroscopy

    SciTech Connect

    Kohout, J. Závěta, K.; Kubániová, D.; Kmječ, T.; Kubíčková, L.; Brázda, P.; Klementová, M.; Šantavá, E.; Lančok, A.

    2015-05-07

    The nanoparticles of ε-Fe{sub 2}O{sub 3} enriched with {sup 57}Fe isotope in amorphous silica matrix were prepared by sol-gel technique starting from a single molecular precursor for both Fe{sub 2}O{sub 3} and silica. From the X-ray powder diffraction pattern ε-Fe{sub 2}O{sub 3} was identified as the major phase and α-Fe{sub 2}O{sub 3} and β-Fe{sub 2}O{sub 3} were observed as minor iron oxide phases. Using the log-normal distribution for fitting the experimental data from the TEM micrographs, the characteristic size of particles d{sub 0} ∼ 25 nm was derived. The rather high coercivity of ∼2.1 T at room temperature was confirmed for our nanoparticle system. From the dependences of magnetization on temperature a two-step magnetic transition spread between 100 K and 153 K was indicated. From the {sup 57}Fe Mössbauer spectra measured in the temperature range of 4.2–300 K, the hyperfine parameters for one tetrahedral and three octahedral sites of ε-Fe{sub 2}O{sub 3} structure were identified. The in-field spectra in the external magnetic fields up to 6 T were taken both above and below the indicated two-step magnetic transition. Their dependence on temperature and external magnetic field suggests that the first step in the temperature range of 153 K–130 K is related to the spin reorientation of the local magnetic moments in the magnetic sublattices and the second step in temperatures 130 K–100 K may be associated with the intermediate spin–high spin state transition of Fe{sup 3+} cation in the tetrahedral sublattice expressed in the change of the hyperfine magnetic field.

  2. Spatial spin-modulated structure and hyperfine interactions of 57Fe nuclei in multiferroics BiFe1- x T x O3 ( T = Sc, Mn; x = 0, 0.05)

    NASA Astrophysics Data System (ADS)

    Rusakov, V. S.; Pokatilov, V. S.; Sigov, A. S.; Matsnev, M. E.; Gapochka, A. M.; Kiseleva, T. Yu.; Komarov, A. E.; Shatokhin, M. S.; Makarova, A. O.

    2016-01-01

    The results of the Mössbauer studies on 57Fe nuclei in multiferroics BiFe1- x T x O3 ( T = Sc, Mn; x = 0, 0.05) in the temperature range of 5.2-300 K have been presented. The Mössbauer spectra have been analyzed in terms of the model of an incommensurate spatial spin-modulated structure of cycloid type. Information has been obtained about the effect of the substitution of Sc and Mn atoms for Fe atoms on the hyperfine parameters of the spectrum: the shift and the quadrupole shift of the Mössbauer line, the isotropic and anisotropic contributions to the hyperfine magnetic field, and also the parameter of anharmonicity of the spatial spin-modulated structure.

  3. The 57Fe hyperfine interactions in the iron bearing phases in different fragments of Chelyabinsk LL5 meteorite: a comparative study using Mössbauer spectroscopy with a high velocity resolution

    NASA Astrophysics Data System (ADS)

    Maksimova, A. A.; Oshtrakh, M. I.; Petrova, E. V.; Grokhovsky, V. I.; Semionkin, V. A.

    2015-04-01

    A comparative study of the 57Fe hyperfine interactions in iron bearing phases of Chelyabinsk LL5 ordinary chondrite fragments with different lithology was carried out using Mössbauer spectroscopy with a high velocity resolution. The obtained values of hyperfine parameters for the same iron bearing phases in different fragments demonstrated small variations. These differences were related to small variations in the Fe local microenvironments in both M1 and M2 sites in olivine and pyroxene, to deviation from stoichiometry in troilite with increase in Fe vacancies and to differences in Ni concentrations in α-Fe(Ni, Co) and γ-Fe(Ni, Co) phases in the metal grains. The obtained differences may indicate a breccia structure of Chelyabinsk LL5 ordinary chondrite.

  4. Implication for using heme methyl hyperfine shifts as indicators of heme seating as related to stereoselectivity in the catabolism of heme by heme oxygenase: in-plane heme versus axial his rotation.

    PubMed

    Ogura, Hiroshi; Evans, John P; de Montellano, Paul R Ortiz; La Mar, Gerd N

    2008-01-01

    The triple mutant of the solubilized, 265-residue construct of human heme oxygenase, K18E/E29K/R183E-hHO, has been shown to redirect the exclusive alpha-regioselectivity of wild-type hHO to primarily beta,delta-selectivity in the cleavage of heme (Wang, J., Evans, J. P., Ogura, H., La Mar, G. N., and Ortiz de Montellano, P. R. (2006) Biochemistry 45, 61-73). The 1H NMR hyperfine shift pattern for the substrate and axial His CbetaH's and the substrate-protein contacts of the cyanide-inhibited protohemin and 2,4-dimethyldeuterohemin complexes of the triple mutant have been analyzed in detail and compared to data for the WT complex. It is shown that protein contacts for the major solution isomers for both substrates in the mutant dictate approximately 90 degrees in-plane clockwise rotation relative to that in the WT. The conventional interpretation of the pattern of substrate methyl hyperfine shifts, however, indicates substrate rotations of only approximately 50 degrees . This paradox is resolved by demonstrating that the axial His25 imidazole ring also rotates counterclockwise with respect to the protein matrix in the mutant relative to that in the WT. The axial His25 CbetaH hyperfine shifts are shown to serve as independent probes of the imidazole plane orientation relative to the protein matrix. The analysis indicates that the pattern of heme methyl hyperfine shifts cannot be used alone to determine the in-plane orientation of the substrate as it relates to the stereospecificity of heme cleavage, without explicit consideration of the orientation of the axial His imidazole plane relative to the protein matrix. PMID:18078349

  5. Anisotropic Fermi Couplings due to Large Unquenched Orbital Angular Momentum: Q-band 1H, 14N and 11B ENDOR of bistrispyrazolylborate Co(II)

    PubMed Central

    Myers, William K.; Scholes, Charles P.; Tierney, David L.

    2009-01-01

    We report Q-band ENDOR of 1H, 14N, and 11B at the g|| extreme of the EPR spectrum of bistrispyrazolylborate Co(II), Co(Tp)2 and two structural analogs. This trigonally symmetric, high-spin (hs) S = 3/2 Co(II) complex shows large unquenched ground–state orbital angular momentum, which leads to highly anisotropic electronic g-values [g|| = 8.48, g⊥ = 1.02]. The large g-anisotropy is shown to result in large dipolar couplings near g|| and uniquely anisotropic 14N Fermi couplings, which arise from spin transferred to the nitrogen 2s orbital (2.2 %) via anti-bonding interactions with singly occupied metal dx2−y2 and dz2 orbitals. Large, well-resolved 1H and 11B dipolar couplings were also observed. Taken in concert with our previous X-band ENDOR measurements at g⊥ (Myers, et al, Inorg. Chem. 2008, 47, 6701–6710), the present data allow a detailed analysis of the dipolar hyperfine tensors of two of the four symmetry distinct protons in the parent molecule. In the substituted analogs, changes in hyperfine coupling due to altered metal-proton distances give further evidence of an anisotropic Fermi contact interaction. For the pyrazolyl 3H proton, the data indicate a 0.2 MHz anisotropic contact interaction and ~ 4 % transfer of spin away from Co(II). Dipolar coupling also dominates for the axial boron atoms, consistent with their distance from the Co(II) ion, and resolved 11B quadrupolar coupling showed ~ 30 % electronic inequivalence between the B-H and B-C sp3 bonds. This is the first comprehensive ENDOR study of any hs Co(II) species and lays the foundation for future development. PMID:19591466

  6. Measure synchronization in a spin-orbit-coupled bosonic Josephson junction

    NASA Astrophysics Data System (ADS)

    Wang, Wen-Yuan; Liu, Jie; Fu, Li-Bin

    2015-11-01

    We present measure synchronization (MS) in a bosonic Josephson junction with spin-orbit coupling. The two atomic hyperfine states are coupled by a Raman dressing scheme, and they are regarded as two orientations of a pseudo-spin-1 /2 system. A feature specific to a spin-orbit-coupled (SOC) bosonic Josephson junction is that the transition from non-MS to MS dynamics can be modulated by Raman laser intensity, even in the absence of interspin atomic interaction. A phase diagram of non-MS and MS dynamics as functions of Raman laser intensity and Josephson tunneling amplitude is presented. Taking into account interspin atomic interactions, the system exhibits MS breaking dynamics resulting from the competition between intraspin and interspin atomic interactions. When interspin atomic interactions dominate in the competition, the system always exhibits MS dynamics. For interspin interaction weaker than intraspin interaction, a window for non-MS dynamics is present. Since SOC Bose-Einstein condensates provide a powerful platform for studies on physical problems in various fields, the study of MS dynamics is valuable in researching the collective coherent dynamical behavior in a spin-orbit-coupled bosonic Josephson junction.

  7. Exchange coupling between silicon donors: The crucial role of the central cell and mass anisotropy

    NASA Astrophysics Data System (ADS)

    Pica, G.; Lovett, B. W.; Bhatt, R. N.; Lyon, S. A.

    2014-06-01

    Donors in silicon are now demonstrated as one of the leading candidates for implementing qubits and quantum information processing. Single qubit operations, measurements, and long coherence times are firmly established, but progress on controlling two qubit interactions has been slower. One reason for this is that the interdonor exchange coupling has been predicted to oscillate with separation, making it hard to estimate in device designs. We present a multivalley effective mass theory of a donor pair in silicon, including both a central cell potential and the effective mass anisotropy intrinsic in the Si conduction band. We are able to accurately describe the single donor properties of valley-orbit coupling and the spatial extent of donor wave functions, highlighting the importance of fitting measured values of hyperfine coupling and the orbital energy of the 1s levels. Ours is a simple framework that can be applied flexibly to a range of experimental scenarios, but it is nonetheless able to provide fast and reliable predictions. We use it to estimate the exchange coupling between two donor electrons and we find a smoothing of its expected oscillations, and predict a monotonic dependence on separation if two donors are spaced precisely along the [100] direction.

  8. Entangled states decoherence in coupled molecular spin clusters

    NASA Astrophysics Data System (ADS)

    Troiani, Filippo; Szallas, Attila; Bellini, Valerio; Affronte, Marco

    2010-03-01

    Localized electron spins in solid-state systems are widely investigated as potential building blocks of quantum devices and computers. While most efforts in the field have been focused on semiconductor low-dimensional structures, molecular antiferromagnets were recently recognized as alternative implementations of effective few-level spin systems. Heterometallic, Cr-based spin rings behave as effective spin-1/2 systems at low temperature and show long decoherence times [1]; besides, they can be chemically linked and magnetically coupled in a controllable fascion [2]. Here, we theoretically investigate the decoherence of the Bell states in such ring dimers, resulting from hyperfine interactions with nuclear spins. Based on a microscopic description of the molecules [3], we simulate the effect of inhomogeneous broadening, spectral diffusion and electron-nuclear entanglement on the electron-spin coherence, estimating the role of the different nuclei (and of possible chemical substitutions), as well as the effect of simple spin-echo sequences. References: [1] F. Troiani, et al., Phys. Rev. Lett. 94, 207208 (2005). [2] G. A. Timco, S: Carretta, F. Troiani et al., Nature Nanotech. 4, 173 (2009). [3] F. Troiani, V. Bellini, and M. Affronte, Phys. Rev. B 77, 054428 (2008).

  9. Structure and quadrupole coupling measurements on ClF3

    NASA Astrophysics Data System (ADS)

    Haubrich, S. T.; Roehrig, M. A.; Kukolich, S. G.

    1990-07-01

    Seventy-nine new microwave transitions for 35ClF3 and 37ClF3 in the 6-18 GHz range were measured using a Flygare-Balle-type spectrometer. Rotational transition frequencies were used to obtain ``effective'' structure parameters for the ground vibrational state zCl-F (along C2 axis)=1.5985(4) Å, rCl-F =1.700 73(5) Å and ΘF-Cl-F =87.48(4)°. Analysis of hyperfine structure due to chlorine quadrupole coupling and observed transition frequencies yield the following molecular parameters for 35ClF3: A=13 748.25(1) MHz, B=4611.719(2) MHz, C=3448.629(3) MHz, eQqaa=82.03(3) MHz, and eQqbb=65.35(2) MHz. Molecular parameters obtained for 37ClF3 are: A=13 653.54(1) MHz, B=4611.866(2) MHz, C=3442.719(4) MHz, eQqaa=64.66(4) MHz, and eQqbb=51.53(3) MHz.

  10. Perturbation on hyperfine-enhanced 141Pr nuclear spin dynamics associated with antiferroquadrupolar order in PrV2Al20

    NASA Astrophysics Data System (ADS)

    Ito, T. U.; Higemoto, W.; Sakai, A.; Tsujimoto, M.; Nakatsuji, S.

    2015-09-01

    The nature of multipolar order and hyperfine-enhanced (HE) 141Pr nuclear spin dynamics in PrV2Al20 was investigated using the muon spin relaxation technique. No explicit sign of time-reversal symmetry breaking was found below the multipolar order temperature TQ˜0.6 K in a zero applied field as anticipated on the basis of the antiferroquadrupolar (AFQ) order picture proposed by Sakai and Nakatsuji [J. Phys. Soc. Jpn. 80, 063701 (2011), 10.1143/JPSJ.80.063701]. Further evidence of the nonmagnetic ground state was obtained from the observation of HE 141Pr nuclear spin fluctuations in the MHz scale. A marked increase in the muon spin-lattice relaxation rate (1 /T1 ,μ) was observed below 1 K with decreasing temperature, which was attributed to the perturbation on the HE 141Pr nuclear spin dynamics associated with the development of AFQ correlations. The longitudinal field dependence of 1 /T1 ,μ revealed that the enhanced 141Pr nuclear spin accidentally has an effective gyromagnetic ratio close to that of the muon.

  11. Hyperfine transitions in ground state hydrogen-like {sup 165}Ho{sup 66+} and {sup 185,187}Re{sup 74+}

    SciTech Connect

    Crespo Lopez-Urrutia, J.R.; Beiersdorfer, P.; Savin, D.W.; Widmann, K.

    1997-02-01

    Spontaneous line emission due to the hyperfine splitting of the ground state of highly charged hydrogen-like ions excited by electron collisions was measured using an Electron Beam Ion Trap. The F=4 to F=3 transition of the 1s {sup 2}S{sub 1/2} configuration of {sup 165}Ho{sup 66+} was identified at (5726.4{plus_minus}1.5){Angstrom}. The F=3 to F=2 transition for the two isotopes {sup 185,187}Re{sup 74+} were found at (4512{plus_minus}2){Angstrom} and (4557{plus_minus}2){Angstrom}. We infer the nuclear dipole magnetic moment of {sup 165}Ho to be 4.1267(11) n.m., with five times higher accuracy than previous measurements. For {sup 185,187}Re we determine 3.153(2) n.m. and 3.184(2) n.m., respectively, in disagreement with a tabulated NMR measurement. {copyright} {ital 1997 American Institute of Physics.}

  12. The influence of hyperfine structure and isotope shift on the detection of Rb by 2 f-wavelength modulation diode laser absorption spectrometry—experimental verification of simulations

    NASA Astrophysics Data System (ADS)

    Gustafsson, Jörgen; Axner, Ove

    1998-12-01

    This work presents an experimental verification of a previously developed methodology for simulation of the 2 f-wavelength modulation diode laser absorption spectrometry technique (2 f-WM-DLAS) when the influence of hyperfine structure, isotope shift and collisional broadening and shift of an atomic transition is taken into account [J. Gustafsson, D. Rojas and O. Axner, Spectrochim. Acta, 52B, 1937-1953 (1997)]. The pilot element in the simulations was Rb, detected at the 780 nm 5s 2S 1/2-5p 2P 3/2 transition, in low-pressure cells and atmospheric-pressure reservoirs (e.g. graphite furnaces). This experimental investigation verifies that the simulations are able to predict, with good accuracy, experimental 2 f-WM signals from Rb atoms under both low-pressure, room-temperature conditions and atmospheric-pressure, high-temperature conditions. This implies that the previously published simulation methodology can be used for predicting and optimizing 2 f-WM signal strengths and shapes from Rb atoms (and thereby presumably also from other atoms) under a variety of pressure and temperature conditions.

  13. Improved V II Log(gf) Values, Hyperfine Structure Constants, and Abundance Determinations in the Photospheres of the Sun and Metal-poor Star HD 84937

    NASA Astrophysics Data System (ADS)

    Wood, M. P.; Lawler, J. E.; Den Hartog, E. A.; Sneden, C.; Cowan, J. J.

    2014-10-01

    New experimental absolute atomic transition probabilities are reported for 203 lines of V II. Branching fractions are measured from spectra recorded using a Fourier transform spectrometer and an echelle spectrometer. The branching fractions are normalized with radiative lifetime measurements to determine the new transition probabilities. Generally good agreement is found between this work and previously reported V II transition probabilities. Two spectrometers, independent radiometric calibration methods, and independent data analysis routines enable a reduction in systematic uncertainties, in particular those due to optical depth errors. In addition, new hyperfine structure constants are measured for selected levels by least squares fitting line profiles in the FTS spectra. The new V II data are applied to high resolution visible and UV spectra of the Sun and metal-poor star HD 84937 to determine new, more accurate V abundances. Lines covering a range of wavelength and excitation potential are used to search for non-LTE effects. Very good agreement is found between our new solar photospheric V abundance, log ɛ(V) = 3.95 from 15 V II lines, and the solar-system meteoritic value. In HD 84937, we derive [V/H] = -2.08 from 68 lines, leading to a value of [V/Fe] = 0.24.

  14. Hyperfine structure and magnetic properties of Zn doped Co{sub 2}Z hexaferrite investigated by high-field Mössbauer spectroscopy

    SciTech Connect

    Lim, Jung Tae; Kim, Chul Sung

    2015-05-07

    The polycrystalline samples of Ba{sub 3}Co{sub 2−x}Zn{sub x}Fe{sub 24}O{sub 41} (x = 0.0, 0.5, 1.0, 1.5, and 2.0) were synthesized by the standard solid-state-reaction method. Based on the XRD patterns analyzed by Rietveld refinement, the structure was determined to be single-phased hexagonal with space group of P6{sub 3}/mmc. With increasing Zn ion concentration, the unit cell volume (V{sub u}) of samples was increased, as the sites of Fe{sup 3+} ions changed from tetrahedral to octahedral sites. We have obtained zero-field Mössbauer spectra of all samples at various temperatures ranging from 4.2 to 750 K. The measured spectra below T{sub C} were analyzed with six distinguishable sextets due to the superposition of ten-sextets for Fe sites, corresponding to the Z-type hexagonal ferrite. Also, the hyperfine field (H{sub hf}) and electric quadrupole shift (E{sub Q}) have shown abrupt changes around spin transition temperature (T{sub S}). In addition, Mössbauer spectra of all samples at 4.2 K were taken with an applied field ranging from 0 to 50 kOe, which indicates the decrease in the canting angle between applied field and H{sub hf} of samples with increasing Zn concentration.

  15. Effect of heterovalent substitutions in yttrium chromite on the hyperfine interactions of 119Sn4+ studied by Mössbauer spectroscopy

    NASA Astrophysics Data System (ADS)

    Fabritchnyi, Pavel B.; Afanasov, Mikhail I.; Mezhuev, Evgeny M.; Wattiaux, Alain; Duttine, Mathieu; Labrugère, Christine

    2016-03-01

    In order to develop the 119Sn Mössbauer spectroscopic probe technique to study magnetically ordered materials, three Ca-substituted yttrium chromites, i.e. Y0.9Ca0.1CrO3, Y0.9Ca0.1Cr0.9Ti0.1O3 and Y0.8Ca0.2Cr0.8Ti0.2O3, doped with 0.3 atom-% Sn4+, were for the first time investigated. 119Sn Mössbauer spectra, recorded at 4.2 K, have allowed, through analysis of the magnetic hyperfine field values, probed by 119Sn nuclei, to gain insight into the local magnetically active surrounding of different Sn4+ ions. In all of these compounds, partial segregation of Sn4+ ions is revealed. In the case of Y0.9Ca0.1CrO3, neither highly oxidized Cr4+ nor Cr6+ species, expected to compensate for the Ca2+ positive charge deficit, is found in the vicinity of the 119Sn4+ probe. In the case of both studied Ti-containing chromites, 119Sn Mössbauer spectra have provided the original indirect evidence for the statistical distribution of Cr3+ and Ti4+ ions over the octahedral sites and permitted characterization of the occurring associates of Sn4+.

  16. Hyperfine structure and magnetic properties of Zn doped Co2Z hexaferrite investigated by high-field Mössbauer spectroscopy

    NASA Astrophysics Data System (ADS)

    Lim, Jung Tae; Kim, Chul Sung

    2015-05-01

    The polycrystalline samples of Ba3Co2-xZnxFe24O41 (x = 0.0, 0.5, 1.0, 1.5, and 2.0) were synthesized by the standard solid-state-reaction method. Based on the XRD patterns analyzed by Rietveld refinement, the structure was determined to be single-phased hexagonal with space group of P63/mmc. With increasing Zn ion concentration, the unit cell volume (Vu) of samples was increased, as the sites of Fe3+ ions changed from tetrahedral to octahedral sites. We have obtained zero-field Mössbauer spectra of all samples at various temperatures ranging from 4.2 to 750 K. The measured spectra below TC were analyzed with six distinguishable sextets due to the superposition of ten-sextets for Fe sites, corresponding to the Z-type hexagonal ferrite. Also, the hyperfine field (Hhf) and electric quadrupole shift (EQ) have shown abrupt changes around spin transition temperature (TS). In addition, Mössbauer spectra of all samples at 4.2 K were taken with an applied field ranging from 0 to 50 kOe, which indicates the decrease in the canting angle between applied field and Hhf of samples with increasing Zn concentration.

  17. Magnetic behavior of LaMn{sub 2}(Si{sub (1−x)}Ge{sub x}){sub 2} compounds characterized by magnetic hyperfine field measurements

    SciTech Connect

    Bosch-Santos, B. Carbonari, A. W.; Cabrera-Pasca, G. A.; Saxena, R. N.

    2014-05-07

    The temperature dependence of the magnetic hyperfine field (B{sub hf}) at Mn atom sites was measured in LaMn{sub 2}(Si{sub (1−x)}Ge{sub x}){sub 2}, with 0 ≤ x ≤ 1, compounds with perturbed γ−γ angular correlation spectroscopy using {sup 111}In({sup 111}Cd) as probe nuclei in the temperature range from 20 K to 480 K. The results show a transition from antiferromagnetic to ferromagnetic ordering for all studied compounds when Ge gradually replaces Si and allowed an accurate determination of the Néel temperature (T{sub N}) for each compound. It was observed that T{sub N} decreases when Ge concentration increases. Conversely, the Curie temperature increases with increase of Ge concentration. This remarkable change in the behavior of the transition temperatures is discussed in terms of the Mn-Mn distance and ascribed to a change in the exchange constant J{sub ex}.

  18. Hyperfine and magnetic properties of a Y{sub x}La{sub 1−x}FeO{sub 3} series (0 ≤ x ≤ 1)

    SciTech Connect

    Cristóbal, A.A.; Botta, P.M.; Bercoff, P.G.

    2015-04-15

    Highlights: • Y{sub x}La{sub 1−x}FeO{sub 3} (0 ≤ x ≤ 1) was synthesized by mechanochemistry. • Two magnetic contributions were identified in the series. • A paramagnetic state is associated with a fraction of the smallest particles. • A ferromagnetic state is attributed to the larger particles. • Annealing of samples favored the formation of Y{sub 3}Fe{sub 5}O{sub 12} impurities. - Abstract: A series of orthoferrites Y{sub x}La{sub 1−x}FeO{sub 3} in the entire range of composition was synthesized at room temperature by mechanochemical activation of oxide mixtures. Phase composition, structure and microstructure of the obtained powder materials were characterized by X-ray diffraction and field-emission scanning electron microscopy. Hyperfine interactions and magnetic properties were determined by Mössbauer spectroscopy, SQUID and vibrating sample magnetometry. Two magnetic contributions could be identified in the series of materials: a paramagnetic state, associated with a fraction of the smallest particles and a ferromagnetic state, attributed to the larger particles. The results showed that the relative proportion of both contributions is very dependent on x, the Y content of samples. From M vs T measurements, it was possible to estimate the blocking temperature distribution for the end members of the series. Annealing of samples produced the elimination of the superparamagnetic behavior and the formation of Y{sub 3}Fe{sub 5}O{sub 12} impurities.

  19. IMPROVED V II log(gf) VALUES, HYPERFINE STRUCTURE CONSTANTS, AND ABUNDANCE DETERMINATIONS IN THE PHOTOSPHERES OF THE SUN AND METAL-POOR STAR HD 84937

    SciTech Connect

    Wood, M. P.; Lawler, J. E.; Den Hartog, E. A.; Sneden, C.; Cowan, J. J. E-mail: jelawler@wisc.edu E-mail: chris@verdi.as.utexas.edu

    2014-10-01

    New experimental absolute atomic transition probabilities are reported for 203 lines of V II. Branching fractions are measured from spectra recorded using a Fourier transform spectrometer and an echelle spectrometer. The branching fractions are normalized with radiative lifetime measurements to determine the new transition probabilities. Generally good agreement is found between this work and previously reported V II transition probabilities. Two spectrometers, independent radiometric calibration methods, and independent data analysis routines enable a reduction in systematic uncertainties, in particular those due to optical depth errors. In addition, new hyperfine structure constants are measured for selected levels by least squares fitting line profiles in the FTS spectra. The new V II data are applied to high resolution visible and UV spectra of the Sun and metal-poor star HD 84937 to determine new, more accurate V abundances. Lines covering a range of wavelength and excitation potential are used to search for non-LTE effects. Very good agreement is found between our new solar photospheric V abundance, log ε(V) = 3.95 from 15 V II lines, and the solar-system meteoritic value. In HD 84937, we derive [V/H] = –2.08 from 68 lines, leading to a value of [V/Fe] = 0.24.

  20. Investigations of the ground-state hyperfine atomic structure and beta decay measurement prospects of {sup 21}Na with improved laser trapping techniques

    SciTech Connect

    Rowe, Mary A.

    1999-05-24

    This thesis describes an experiment in which a neutral atom laser trap loaded with radioactive {sup 21}Na was improved and then used for measurements. The sodium isotope (half-life=22 sec) is produced on line at the 88in cyclotron at Lawrence Berkeley National Laboratory. The author developed an effective magnesium oxide target system which is crucial to deliver a substantive beam of {sup 21}Na to the experiment. Efficient manipulation of the {sup 21}Na beam with lasers allowed 30,000 atoms to be contained in a magneto-optical trap. Using the cold trapped atoms, the author measured to high precision the hyperfine splitting of the atomic ground state of {sup 21}Na. She measured the 3S{sub 1/2}(F=1,m=0)-3S{sub 1/2}(F=2,m=0) atomic level splitting of {sup 21}Na to be 1,906,471,870{+-}200 Hz. Additionally, she achieved initial detection of beta decay from the trap and evaluated the prospects of precision beta decay correlation studies with trapped atoms.