Science.gov

Sample records for inelastic scattering effects

  1. Inelastic Scattering Form Factors

    1992-01-01

    ATHENA-IV computes form factors for inelastic scattering calculations, using single-particle wave functions that are eigenstates of motion in either a Woods-Saxon potential well or a harmonic oscillator well. Two-body forces of Gauss, Coulomb, Yukawa, and a sum of cut-off Yukawa radial dependences are available.

  2. Inelastic scattering in planetary atmospheres. I - The Ring effect, without aerosols

    NASA Technical Reports Server (NTRS)

    Kattawar, G. W.; Young, A. T.; Humphreys, T. J.

    1981-01-01

    The contribution of inelastic molecular scattering (Rayleigh-Brillouin and rotational Raman scattering) to the filling-in of Fraunhofer lines in the light of the blue sky is studied. Aerosol fluorescence is shown to be negligible, and aerosol scattering is ignored. The angular and polarization dependences of the filling-in detail for single scattering are discussed. An approximate treatment of multiple scattering, using a backward Monte Carlo technique, makes it possible to investigate the effects of the ground albedo. As the molecular scatterings alone produce more line-filling than is observed, it seems likely that aerosols dilute the effect by contributing unaltered sunlight to the observed spectra.

  3. Deep and shallow inelastic scattering

    SciTech Connect

    Ray, Heather

    2015-05-15

    In this session we focused on the higher energy deep and shallow inelastic particle interactions, DIS and SIS. DIS interactions occur when the energy of the incident particle beam is so large that the beam is able to penetrate the nucleons inside of the target nuclei. These interactions occur at the smallest level possible, that of the quark-gluon, or parton, level. SIS interactions occur in an intermediate energy range, just below the energy required for DIS interactions. The DIS cross section formula contains structure functions that describe our understanding of the underlying parton structure of nature. The full description of DIS interactions requires three structure functions: two may be measured in charged lepton or neutrino scattering, but one can only be extracted from neutrino DIS data. There are reasons to expect that the impact of nuclear effects could be different for neutrinos engaging in the DIS interaction, vs those felt by leptons. In fact, fits by the nCTEQ collaboration have found that the neutrino-Fe structure functions appear to differ from those extracted from lepton scattering data [1]. To better understand the global picture of DIS and SIS, we chose a three-pronged attack that examined recent experimental results, data fits, and latest theory predictions. Experimental results from neutrino and lepton scattering, as well as collider experiments, were presented.

  4. Deep inelastic scattering near the endpoint in soft-collinear effective theory

    SciTech Connect

    Chay, Junegone; Kim, Chul

    2007-01-01

    We apply the soft-collinear effective theory to deep inelastic scattering near the endpoint region. The forward scattering amplitude and the structure functions are shown to factorize as a convolution of the Wilson coefficients, the jet functions, and the parton distribution functions. The behavior of the parton distribution functions near the endpoint region is considered. It turns out that it evolves with the Altarelli-Parisi kernel even in the endpoint region, and the parton distribution function can be factorized further into a collinear part and the soft Wilson line. The factorized form for the structure functions is obtained by the two-step matching, and the radiative corrections or the evolution for each factorized part can be computed in perturbation theory. We present the radiative corrections of each factorized part to leading order in {alpha}{sub s}, including the zero-bin subtraction for the collinear part.

  5. First Search for the EMC Effect and Nuclear Shadowing in Neutrino Nucleus Deep Inelastic Scattering at MINERvA

    SciTech Connect

    Mousseau, Joel A.

    2015-01-01

    Decades of research in electron-nucleus deep inelastic scattering (DIS) have provided a clear picture of nuclear physics at high momentum transfer. While these effects have been clearly demonstrated by experiment, the theoretical explanation of their origin in some kinematic regions has been lacking. Particularly, the effects in the intermediate regions of Bjorken-x, anti-shadowing and the EMC effect have no universally accepted quantum mechanical explanation. In addition, these effects have not been measured systematically with neutrino-nucleus deep inelastic scattering, due to experiments lacking multiple heavy targets.

  6. Gate-opening effect in ZIF-8: the first experimental proof using inelastic neutron scattering.

    PubMed

    Casco, M E; Cheng, Y Q; Daemen, L L; Fairen-Jimenez, D; Ramos-Fernández, E V; Ramirez-Cuesta, A J; Silvestre-Albero, J

    2016-03-01

    The gate-opening phenomenon in ZIFs is of paramount importance to understand their behavior in industrial molecular separations. Here we show for the first time using in situ inelastic neutron scattering (INS) the swinging of the -CH3 groups and the imidazolate linkers in the prototypical ZIF-8 and ZIF-8@AC hybrid materials upon exposure to mild N2 pressure.

  7. Gate-opening effect in ZIF-8: the first experimental proof using inelastic neutron scattering.

    PubMed

    Casco, M E; Cheng, Y Q; Daemen, L L; Fairen-Jimenez, D; Ramos-Fernández, E V; Ramirez-Cuesta, A J; Silvestre-Albero, J

    2016-03-01

    The gate-opening phenomenon in ZIFs is of paramount importance to understand their behavior in industrial molecular separations. Here we show for the first time using in situ inelastic neutron scattering (INS) the swinging of the -CH3 groups and the imidazolate linkers in the prototypical ZIF-8 and ZIF-8@AC hybrid materials upon exposure to mild N2 pressure. PMID:26845644

  8. Polarization transfer in inelastic scattering and pionic models of the EMC effect

    SciTech Connect

    Carey, T.A.; Jones, K.W.; McClelland, J.B.; Moss, J.M.; Rees, L.B.; Tanaka, N.; Bacher, A.D.

    1985-01-01

    The aim of the experiment reported was to make a precise test of the enhanced pion field model in a medium-energy scattering experiment. The quantity probed is the spin-longitudinal response function, a measure of the nuclear pion density which is used explicitly in the pion-excess models of the EMC effect. The point of reference used is deuterium. The spin-dependent response functions for heavy targets and /sup 2/H are compared using identical experimental techniques. The technique of complete polarization transfer is used to separate the spin-longitudinal and spin-transverse response in the continuum. The experiment consisted of precise determinations of the polarization transfer coefficients for 500 MeV protons inelastically scattered from Pb, Ca, and /sup 2/H. The experiment utilized longitudinal, sideways, and normal polarized beams in conjunction with final polarization analysis from the focal-plane polarimeter of the high-resolution spectrometer. Quantities constructed from these data are the longitudinal and transverse spin-flip probabilities. Calculations were performed of the ratio of longitudinal to transverse response functions and of the EMC effect with the same model. No evidence was found for collectivity in the isovector spin-longitudinal response function. 10 refs. (LEW)

  9. Perturbative QCD effects observed in 490 GeV deep-inelastic muon scattering

    SciTech Connect

    Adams, M.R.; Aied, S.; Anthony, P.L.; Baker, M.D.; Bartlett, J.; Bhatti, A.A.; Braun, H.M.; Busza, W.; Conrad, J.M.; Coutrakon, G.; Davisson, R.; Derado, I.; Dhawan, S.K.; Dougherty, W.; Dreyer, T.; Dziunikowska, K.; Eckardt, V.; Ecker, U.; Erdmann, M.; Eskreys, A.; Figiel, J.; Gebauer, H.J.; Geesaman, D.F.; Gilman, R.; Green, M.C.; Haas, J.; Halliwell, C.; Hanlon, J.; Hantke, D.; Hughes, V.W.; Jackson, H.E.; Jaffe, D.E.; Jancso, G.; Jansen, D.M.; Kaufman, S.; Kennedy, R.D.; Kirk, T.; Kobrak, H.G.E.; Krzywdzinski, S.; Kunori, S.; Lord, J.J.; Lubatti, H.J.; McLeod, D.; Magill, S.; Malecki, P.; Manz, A.; Melanson, H.; Michael, D.G.; Mohr, W.; Montgomery, H.E.; Morfin, J.G.; Nickerson, R.B.; O'Day, S.; Olkiewicz, K.; Osborne, L.; Papavassiliou, V.; Pawlik, B.; Pipkin, F.M.; Ramberg, E.J.; Roeser, A.; Ryan, J.J.; Salgado, C.W.; Salvarani, A.; Schellman, H.; Schmitt, M.; Schmitz, N.; Schueler, K.P.; Skuja, A.; Snow, G.A.; Soeldner-Rembold, S.; Steinberg, P.H.; Stier, H.E.; Stopa, P.; Swanso

    1993-12-01

    Results on forward charged hadrons in 490 GeV deep-inelastic muon scattering are presented. The transverse momenta, azimuthal asymmetry, and energy flow of events with four or more forward charged hadrons are studied. The range of the invariant hadronic mass squared 300[lt][ital W][sup 2][lt]900 GeV[sup 2]/[ital c][sup 4] extends higher than previous deep-inelastic muon scattering experiments. Data are compared to the predictions of the Lund Monte Carlo model with perturbative QCD simulated by matrix elements, parton showers, and color dipole radiation. All of the QCD-based models are consistent with the data while a model without QCD processes is not. Correlations with the multiplicity-independent event variable [Pi][congruent][summation][vert bar][ital p][sub [ital T

  10. Electroweak higher-order effects and theoretical uncertainties in deep-inelastic neutrino scattering

    SciTech Connect

    Diener, K.-P.O.; Dittmaier, S.; Hollik, W.

    2005-11-01

    A previous calculation of electroweak O({alpha}) corrections to deep-inelastic neutrino scattering, as e.g. measured by NuTeV and NOMAD, is supplemented by higher-order effects. In detail, we take into account universal two-loop effects from {delta}{alpha} and {delta}{rho} as well as higher-order final-state photon radiation off muons in the structure function approach. Moreover, we make use of the recently released O({alpha})-improved parton distributions MRST2004QED and identify the relevant QED factorization scheme, which is DIS-like. As a technical by-product, we describe slicing and subtraction techniques for an efficient calculation of a new type of real corrections that are induced by the generated photon distribution. A numerical discussion of the higher-order effects suggests that the remaining theoretical uncertainty from unknown electroweak corrections is dominated by nonuniversal two-loop effects and is of the order 0.0003 when translated into a shift in sin{sup 2}{theta}{sub W}=1-M{sub W}{sup 2}/M{sub Z}{sup 2}. The O({alpha}) corrections implicitly included in the parton distributions lead to a shift of about 0.0004.

  11. Signatures of strong correlation effects in resonant inelastic x-ray scattering studies on cuprates

    NASA Astrophysics Data System (ADS)

    Li, Wan-Ju; Lin, Cheng-Ju; Lee, Ting-Kuo

    2016-08-01

    Recently, spin excitations in doped cuprates have been measured using resonant inelastic x-ray scattering. The paramagnon dispersions show the large hardening effect in the electron-doped systems and seemingly doping independence in the hole-doped systems, with the energy scales comparable to that of the antiferromagnetic (AFM) magnons. This anomalous hardening effect and the lack of softening were partially explained by using the strong-coupling t -J model but with a three-site term [Nat. Commun. 5, 3314 (2014), 10.1038/ncomms4314], although the hardening effect is already present even without the latter. By considering the t -t'-t''-J model and using the slave-boson mean-field theory, we obtain, via the spin-spin susceptibility, the spin excitations in qualitative agreement with the experiments. The doping-dependent bandwidth due to the strong correlation physics is the origin of the hardening effect. We also show that dispersions in the AFM regime, different from those in the paramagnetic (PM) regime, hardly vary with dopant density. These excitations are mainly collective in nature instead of particle-hole-like. We further discuss the interplay and different contributions of these two kinds of excitations in the PM phase and show that the dominance of the collective excitation increases with decreasing dopant concentrations.

  12. Inclusive inelastic scattering of heavy ions and nuclear correlations

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Townsend, Lawrence W.; Wilson, John W.; Khandelwal, Govind S.

    1990-01-01

    Calculations of inclusive inelastic scattering distributions for heavy ion collisions are considered within the high energy optical model. Using ground state sum rules, the inclusive projectile and complete projectile-target inelastic angular distributions are treated in both independent particle and correlated nuclear models. Comparisons between the models introduced are made for alpha particles colliding with He-4, C-12, and O-16 targets and protons colliding with O-16. Results indicate that correlations contribute significantly, at small momentum transfers, to the inelastic sum. Correlation effects are hidden, however, when total scattering distributions are considered because of the dominance of elastic scattering at small momentum transfers.

  13. Perturbative QCD effects observed in 490 GeV deep-inelastic muon scattering

    NASA Astrophysics Data System (ADS)

    Adams, M. R.; Aïd, S.; Anthony, P. L.; Baker, M. D.; Bartlett, J.; Bhatti, A. A.; Braun, H. M.; Busza, W.; Conrad, J. M.; Coutrakon, G.; Davisson, R.; Derado, I.; Dhawan, S. K.; Dougherty, W.; Dreyer, T.; Dziunikowska, K.; Eckardt, V.; Ecker, U.; Erdmann, M.; Eskreys, A.; Figiel, J.; Gebauer, H. J.; Geesaman, D. F.; Gilman, R.; Green, M. C.; Haas, J.; Halliwell, C.; Hanlon, J.; Hantke, D.; Hughes, V. W.; Jackson, H. E.; Jaffe, D. E.; Jancso, G.; Jansen, D. M.; Kaufman, S.; Kennedy, R. D.; Kirk, T.; Kobrak, H. G.; Krzywdzinski, S.; Kunori, S.; Lord, J. J.; Lubatti, H. J.; McLeod, D.; Magill, S.; Malecki, P.; Manz, A.; Melanson, H.; Michael, D. G.; Mohr, W.; Montgomery, H. E.; Morfin, J. G.; Nickerson, R. B.; O'day, S.; Olkiewicz, K.; Osborne, L.; Papavassiliou, V.; Pawlik, B.; Pipkin, F. M.; Ramberg, E. J.; Röser, A.; Ryan, J. J.; Salgado, C. W.; Salvarani, A.; Schellman, H.; Schmitt, M.; Schmitz, N.; Schüler, K. P.; Skuja, A.; Snow, G. A.; Söldner-Rembold, S.; Steinberg, P. H.; Stier, H. E.; Stopa, P.; Swanson, R. A.; Talaga, R.; Tentindo-Repond, S.; Trost, H.-J.; Venkataramania, H.; Wilhelm, M.; Wilkes, J.; Wilson, Richard; Wittek, W.; Wolbers, S. A.; Zhao, T.

    1993-12-01

    Results on forward charged hadrons in 490 GeV deep-inelastic muon scattering are presented. The transverse momenta, azimuthal asymmetry, and energy flow of events with four or more forward charged hadrons are studied. The range of the invariant hadronic mass squared 300inelastic muon scattering experiments. Data are compared to the predictions of the Lund Monte Carlo model with perturbative QCD simulated by matrix elements, parton showers, and color dipole radiation. All of the QCD-based models are consistent with the data while a model without QCD processes is not. Correlations with the multiplicity-independent event variable Π~=J||pT|| are studied. The relationship between the azimuthal asymmetry and transverse momentum of forward hadrons is also presented. The data are most consistent with intrinsic parton transverse momentum squared k2T of 0.25 GeV2/c2.

  14. Solution of a Simple Inelastic Scattering Problem

    ERIC Educational Resources Information Center

    Knudson, Stephen K.

    1975-01-01

    Provides an analytical solution of a model representing the collision of an atom with a harmonic oscillator, interacting via a repulsive square well potential. Presents results for various energies and strengths of inelastic scattering. (Author/CP)

  15. Measurement of partonic nuclear effects in deep-inelastic neutrino scattering using MINERvA

    DOE PAGESBeta

    Mousseau, J.

    2016-04-19

    Here, the MINERvA Collaboration reports a novel study of neutrino-nucleus charged-current deep inelastic scattering (DIS) using the same neutrino beam incident on targets of polystyrene, graphite, iron, and lead. Results are presented as ratios of C, Fe, and Pb to CH. The ratios of total DIS cross sections as a function of neutrino energy and flux-integrated differential cross sections as a function of the Bjorken scaling variable x are presented in the neutrino-energy range of 5–50 GeV. Based on the predictions of charged-lepton scattering ratios, good agreement is found between the data and prediction at medium x and low neutrino energy.more » However, the ratios appear to be below predictions in the vicinity of the nuclear shadowing region, x < 0.1. This apparent deficit, reflected in the DIS cross-section ratio at high Eν, is consistent with previous MINERvA observations [B. Tice (MINERvA Collaboration), Phys. Rev. Lett. 112, 231801 (2014).] and with the predicted onset of nuclear shadowing with the axial-vector current in neutrino scattering.« less

  16. Measurement of partonic nuclear effects in deep-inelastic neutrino scattering using MINERvA

    NASA Astrophysics Data System (ADS)

    Mousseau, J.; Wospakrik, M.; Aliaga, L.; Altinok, O.; Bellantoni, L.; Bercellie, A.; Betancourt, M.; Bodek, A.; Bravar, A.; Budd, H.; Cai, T.; Carneiro, M. F.; Christy, M. E.; Chvojka, J.; da Motta, H.; Devan, J.; Dytman, S. A.; Díaz, G. A.; Eberly, B.; Felix, J.; Fields, L.; Fine, R.; Gago, A. M.; Galindo, R.; Gallagher, H.; Ghosh, A.; Golan, T.; Gran, R.; Harris, D. A.; Higuera, A.; Hurtado, K.; Kiveni, M.; Kleykamp, J.; Kordosky, M.; Le, T.; Maher, E.; Manly, S.; Mann, W. A.; Marshall, C. M.; Martinez Caicedo, D. A.; McFarland, K. S.; McGivern, C. L.; McGowan, A. M.; Messerly, B.; Miller, J.; Mislivec, A.; Morfín, J. G.; Naples, D.; Nelson, J. K.; Norrick, A.; Nuruzzaman; Osta, J.; Paolone, V.; Park, J.; Patrick, C. E.; Perdue, G. N.; Rakotondravohitra, L.; Ramirez, M. A.; Ransome, R. D.; Ray, H.; Ren, L.; Rimal, D.; Rodrigues, P. A.; Ruterbories, D.; Schellman, H.; Schmitz, D. W.; Solano Salinas, C. J.; Tagg, N.; Tice, B. G.; Valencia, E.; Walton, T.; Wolcott, J.; Zavala, G.; Zhang, D.; Minerν A Collaboration

    2016-04-01

    The MINERvA Collaboration reports a novel study of neutrino-nucleus charged-current deep inelastic scattering (DIS) using the same neutrino beam incident on targets of polystyrene, graphite, iron, and lead. Results are presented as ratios of C, Fe, and Pb to CH. The ratios of total DIS cross sections as a function of neutrino energy and flux-integrated differential cross sections as a function of the Bjorken scaling variable x are presented in the neutrino-energy range of 5-50 GeV. Based on the predictions of charged-lepton scattering ratios, good agreement is found between the data and prediction at medium x and low neutrino energy. However, the ratios appear to be below predictions in the vicinity of the nuclear shadowing region, x <0.1 . This apparent deficit, reflected in the DIS cross-section ratio at high Eν, is consistent with previous MINERvA observations [B. Tice et al. (MINERvA Collaboration), Phys. Rev. Lett. 112, 231801 (2014).] and with the predicted onset of nuclear shadowing with the axial-vector current in neutrino scattering.

  17. Twist-four effects in deep inelastic neutrino scattering and sinStheta/sub w/

    SciTech Connect

    Fajfer, S.; Oakes, R.J.

    1985-07-01

    In addition to the standard perturbative QCD corrections to deep inelastic scattering, there are nonperturbative twist-four corrections which behave like 1/QS relative to the lnQS leading log corrections. We have calculated the twist-four, spin-one and spin-two corrections to sigma/sub NC/, sigma/sub CC/, R/sub nu/ and R/sub anti nu/ using the following procedure: The bilocal product of the weak currents is expanded into local operators using the Wilson operator product expansion. The coefficient functions obey the renormalization group equations and, neglecting the anomalous dimensions of the operators, were calculated using perturbative techniques. The nucleon matrix elements of the local operators can then be evaluated assuming some quark confinement model. We found that twist-four, spin-two corrections to the neutral current neutrino scattering decreases sinStheta/sub w/ by about 1%. Taking into account the twist-four, spin-two corrections for the charged current cross section, we found that they give a dominant contribution to the ratio R/sub nu/ and increased sinStheta/sub w/ by about 0.5%. We also have studied the model dependence of our results, and we have found that the twist-four, spin-two corrections to sinStheta/sub w/ are quite model dependent. The twist-four, spin-one corrections to the neutrino scattering were also calculated. These corrections come from two-quark, one-gluon operators and even at low QS their contribution was found to be considerably smaller than the twist-four, spin-two corrections.

  18. Parity-Violation in Deep Inelastic Scattering

    NASA Astrophysics Data System (ADS)

    Paschke, K. D.

    2009-08-01

    The completion of the planned 12 GeV upgrade at Jefferson Lab will open a new avenue for precision studies of the high-x structure of the nucleon through parity-violation in deeply-inelastic scattering (PV-DIS). PV-DIS would be a clean technique for studying quark-level charge symmetry violation, probing higher-twist effects and for a measurement of the structure function ratio d/u at high x. In addition to these topics in hadronic physics, these measurements would also provide access to a linear combination of the poorly measured axial electron-quark weak couplings C2u and C2d, thus provide an important test of the electroweak Standard Model.

  19. Parity violation in deep inelastic scattering

    SciTech Connect

    Souder, P.

    1994-04-01

    AA beam of polarized electrons at CEBAF with an energy of 8 GeV or more will be useful for performing precision measurements of parity violation in deep inelastic scattering. Possible applications include precision tests of the Standard Model, model-independent measurements of parton distribution functions, and studies of quark correlations.

  20. Neutron inelastic scattering by amino acids

    SciTech Connect

    Thaper, C.L.; Sinha, S.K.; Dasannacharya, B.A.

    1982-01-01

    Inelastic neutron scattering experiments on normal, N-deuterated glycine, normal and N-deuterated alanine, L-valine, L-tyrosine and, L-phenylalanine at 100 K, are reported. Coupling of the external modes to different hydrogens is discussed.

  1. Lattice modes in molecular crystals measured with nuclear inelastic scattering

    SciTech Connect

    Kohn, V. G.; Chumakov, A. I.; Rueffer, R.

    2006-03-01

    We reveal an important property of nuclear inelastic scattering in a molecular crystal with well-separated lattice and molecular modes: The presence of the molecular modes does not change the shape but merely rescales the lattice part of the energy dependence of nuclear inelastic scattering. Therefore, the density of states (DOS) of the lattice vibrations can be properly derived even from the lattice part of nuclear inelastic scattering alone. In this case, one has to substitute the mean recoil energy of a nucleus by the effective recoil energy of the molecule. In first approximation, the ratio of the recoil energies is close to the ratio of the nuclear and molecular masses. More precisely, it is given by the relative area of the lattice part in the entire DOS. The theoretical analysis is verified with numerical calculations for a model DOS and with the experimental data for the decamethyl ferrocene molecular crystal. More generally, the analysis is valid for any region of nuclear inelastic scattering around the central elastic peak with sufficiently narrow lines beyond it. Therefore, the demonstrated property of nuclear inelastic scattering allows for a much shorter measuring time in studies of lattice modes in molecular crystals, low-energy molecular modes in proteins, and in investigations of glass dynamics with molecular probes.

  2. Deep inelastic scattering near the Coulomb barrier

    SciTech Connect

    Gehring, J.; Back, B.; Chan, K.

    1995-08-01

    Deep inelastic scattering was recently observed in heavy ion reactions at incident energies near and below the Coulomb barrier. Traditional models of this process are based on frictional forces and are designed to predict the features of deep inelastic processes at energies above the barrier. They cannot be applied at energies below the barrier where the nuclear overlap is small and friction is negligible. The presence of deep inelastic scattering at these energies requires a different explanation. The first observation of deep inelastic scattering near the barrier was in the systems {sup 124,112}Sn + {sup 58,64}Ni by Wolfs et al. We previously extended these measurements to the system {sup 136}Xe + {sup 64}Ni and currently measured the system {sup 124}Xe + {sup 58}Ni. We obtained better statistics, better mass and energy resolution, and more complete angular coverage in the Xe + Ni measurements. The cross sections and angular distributions are similar in all of the Sn + Ni and Xe + Ni systems. The data are currently being analyzed and compared with new theoretical calculations. They will be part of the thesis of J. Gehring.

  3. Inelastic neutron scattering in valence fluctuation compounds

    SciTech Connect

    Jon M Lawrence

    2011-02-15

    The valence fluctuation compounds are rare earth intermetallics where hybridization of the nearly-localized 4f electrons with the conduction electrons leads to incorporation of the 4f's into the itinerant states. This hybridization slows down the conduction electrons and hence gives them a heavy effective mass, justifying application of the term 'heavy Fermion' (HF) to these materials. During the project period, we grew large single crystals of several such compounds and measured their properties using both standard thermodynamic probes and state-of-the-art inelastic neutron scattering. We obtained three main results. For the intermediate valence compounds CePd{sub 3} and YbAl{sub 3}, we showed that the scattering of neutrons by the fluctuations of the 4f magnetic moment does not have the momentum dependence expected for the itinerant heavy mass state; rather, the scattering is more typical of a localized spin fluctuation. We believe that incoherent scattering localizes the excitation. For the heavy Fermion compound Ce(Ni{sub 0.935}Pd{sub 0.065}){sub 2}Ge{sub 2}, which sits at a T = 0 critical point for transformation into an antiferromagnetic (AF) phase, we showed that the scattering from the AF fluctuations does not exhibit any of the divergences that are expected at a phase transition. We speculate that alloy disorder profoundly suppresses the growth of the fluctuating AF regions, leading to short range clusters rather than regions of infinite size. Finally, we explored the applicability of key concepts used to describe the behavior of rare earth heavy Fermions to uranium based HF compounds where the 5f electrons are itinerant as opposed to localized. We found that scaling laws relating the spin fluctuation energy measured in neutron scattering to the low temperature specific heat and susceptibility are valid for the uranium compounds, once corrections are made for AF fluctuations; however, the degeneracy of the high temperature moment is smaller than expected

  4. Nucleon-nucleon correlations and multiquark cluster effects in semi-inclusive deep inelastic lepton scattering off

    SciTech Connect

    Simula, S.

    1994-04-01

    Semi-inclusive deep inelastic lepton scattering off nuclei is investigated assuming that virtual boson absorption occurs on a hadronic cluster which can be either a two-nucleon correlated pair or a six-quark bag. The differences in the energy distribution of nucleons produced in backward and forward directions are analyzed both at x<1 and x>1.

  5. Heavy quark production in deep-inelastic scattering at HERA.

    SciTech Connect

    Harris, B. W.; Laenen, E.; Moch, S.; Smith, J.

    1999-06-02

    We discuss two topics in the production of heavy quarks in deep-inelastic scattering: the next-to-leading order Monte-Carlo HVQDIS and the next-to-leading logarithmic resummation of soft gluon effects, including estimates of next-to-next-to-leading order corrections therefrom.

  6. Quantum Chromodynamics and Deep Inelastic Scattering

    NASA Astrophysics Data System (ADS)

    Ellis, R. Keith

    2016-10-01

    This article first describes the parton model which was the precursor of the QCD description of hard scattering processes. After the discovery of QCD and asymptotic freedom, the first successful applications were to Deep Inelastic lepton-hadron scattering. The subsequent application of QCD to processes with two initial state hadrons required the understanding and proof of factorization. To take the fledgling theory and turn it into the robust calculational engine it has become today, required a number of technical and conceptual developments which will be described. Prospects for higher loop calculations are also reviewed.

  7. On rainbow scattering in inelastic molecular collisions

    SciTech Connect

    Thomas, Lowell D.

    1980-01-01

    The purpose of this letter is to call attention to a growing misinterpretation in the literature on rainbow scattering in inelastic molecular collisions. The importance of rainbow structures in the angular distributions of elastic scattering cross sections is well established. However, use of approximate cross section formulas has led to an incorrect classification of the types of rainbows which are possible. Actually, however, it is possible to identify two classes of rainbows. If the relevant distributions and classifications are clearly stated, there should be little chance of confusion,

  8. Deep-inelastic muon scattering from nuclei with hadron detection

    SciTech Connect

    Geesaman, D.; Jackson, H.; Kaufman, S.

    1995-08-01

    Deep-inelastic lepton scattering from nuclei provides a direct look at the quark structure of nuclear matter. These reactions revealed the first convincing evidence that the structure of nucleons is modified in the nuclear medium and had profound implications on the understanding of nuclear dynamics. FNAL experiment E665, using the 490-GeV muon beams at Fermi National Accelerator Laboratory, provides new information on the nuclear effects on nucleon properties by studying deep-inelastic muon scattering with coincident hadron detection. The high beam energy makes the experiment particularly suited to the study of the region of x < 0.1 (where x is the fraction of the momentum of the nucleon carried by the struck quark in the infinite momentum frame), and total center-of-mass hadronic energy > 25 GeV, where hard QCD processes are expected to become evident and there are little data from other deep-inelastic measurements.

  9. Inelastic electron scattering from a moving nucleon

    SciTech Connect

    Kuhn, S.E.; Griffioen, K.

    1994-04-01

    The authors propose to measure inelastically scattered electrons in coincidence with spectator protons emitted backwards relative to the virtual photon direction in the reaction d(e, e{prime}p{sub s})X. In a simple spectator model, the backward proton has equal and opposite momentum to the neutron before it is struck, allowing the authors to study the dependence on kinematics and off-shell behaviour of the electron-nucleon inelastic cross section. If the photon couples to a quark in a 6-quark bag, a different dependence of the cross section on the kinematic variables (x, Q{sup 2}, and p{sub s}) can be observed. This proposed experiment requires large acceptance and beam energies above 6 GeV. It is ideally suited for the CEBAF Large Acceptance Spectrometer (CLAS).

  10. A New Polyethylene Scattering Law Determined Using Inelastic Neutron Scattering

    SciTech Connect

    Lavelle, Christopher M; Liu, C; Stone, Matthew B

    2013-01-01

    Monte Carlo neutron transport codes such as MCNP rely on accurate data for nuclear physics cross-sections to produce accurate results. At low energy, this takes the form of scattering laws based on the dynamic structure factor, S (Q, E). High density polyethylene (HDPE) is frequently employed as a neutron moderator at both high and low temperatures, however the only cross-sections available are for T =300 K, and the evaluation has not been updated in quite some time. In this paper we describe inelastic neutron scattering measurements on HDPE at 5 and 300 K which are used to improve the scattering law for HDPE. We describe the experimental methods, review some of the past HDPE scattering laws, and compare computations using these models to the measured S (Q, E). The total cross-section is compared to available data, and the treatment of the carbon secondary scatterer as a free gas is assessed. We also discuss the use of the measurement itself as a scattering law via the 1 phonon approximation. We show that a scattering law computed using a more detailed model for the Generalized Density of States (GDOS) compares more favorably to this experiment, suggesting that inelastic neutron scattering can play an important role in both the development and validation of new scattering laws for Monte Carlo work.

  11. Inclusive Inelastic Electron Scattering from Nuclei

    SciTech Connect

    Fomin, Nadia

    2007-10-26

    Inclusive electron scattering from nuclei at large x and Q{sup 2} is the result of a reaction mechanism that includes both quasi-elastic scattering from nucleons and deep inelastic scattering from the quark consitituents of the nucleons. Data in this regime can be used to study a wide variety of topics, including the extraction of nuclear momentum distributions, the infiuence of final state interactions and the approach to y-scaling, the strength of nucleon-nucleon correlations, and the approach to x-scaling, to name a few. Selected results from the recent experiment E02-019 at the Thomas Jefferson National Accelerator Facility will be shown and their relevance discussed.

  12. CHEMICAL APPLICATIONS OF INELASTIC X-RAY SCATTERING

    SciTech Connect

    HAYASHI,H.; UDAGAWA,Y.; GILLET,J.M.; CALIEBE,W.A.; KAO,C.C.

    2001-08-01

    Inelastic x-ray scattering (IXS), complementary to other more established inelastic scattering probes, such as light scattering, electron scattering, and neutron scattering, is becoming an important experimental technique in the study of elementary excitations in condensed matters. Over the past decade, IXS with total energy resolution of few meV has been achieved, and is being used routinely in the study of phonon dispersions in solids and liquids as well as dynamics in disordered and biological systems. In the study of electronic excitations, IXS with total energy resolution on the order of 100 meV to 1 eV is gaining wider applications also. For example, IXS has been used to study collective excitations of valence electrons, single electron excitations of valence electrons, as well as core electron excitations. In comparison with the alternative scattering techniques mentioned above, IXS has several advantages. First, IXS probes the full momentum transfer range of the dielectric response of the sample, whereas light scattering is limited to very small momentum transfers, and electron scattering suffers the effects of multiple scattering at large momentum transfers. Second, since IXS measures the bulk properties of the sample it is not surface sensitive, therefore it does not require special preparation of the sample. The greater flexibility in sample conditions and environments makes IXS an ideal probe in the study of liquids and samples under extreme temperature, pressure, and magnetic field. Third, the tunability of synchrotron radiation sources enables IXS to exploit element specificity and resonant enhancement of scattering cross sections. Fourth, IXS is unique in the study of dynamics of liquids and amorphous solids because it can probe the particular region of energy-momentum transfer phase space, which is inaccessible to inelastic neutron scattering. On the other hand, the main disadvantages of IXS are the small cross sections and the strong absorption of

  13. Inelastic Scattering Of Electrons By Protons

    DOE R&D Accomplishments Database

    Cone, A. A.; Chen, K. W.; Dunning, J. R. Jr.; Hartwig, G.; Ramsey, N. F.; Walker, J. K.; Wilson, R.

    1966-12-01

    The inelastic scattering of electrons by protons has been measured at incident electron energies up to 5 BeV/c and momentum transfers q{sup 2}=4(BeV/c){sup 2}. Excitation of known nucleon resonances at M=1238, 1512, 1688 and possibly 1920 MeV have been observed. The calculations for the resonance at M=1238 MeV have been compared with calculations by Adler based on the dispersion theory of Chew, Goldberger, Low and Nambu. The agreement is good. Qualitative models are discussed for the other resonances.

  14. GiBUU and shallow inelastic scattering

    SciTech Connect

    Lalakulich, O.; Mosel, U.

    2015-05-15

    In this talk we shortly describe the physics contents of the GiBUU transport code, used to describe lepton scattering off nuclei. Particular attention will be given to validation of the GiBUU in pion-, electron- and photon-induced reactions, which serve as a benchmark for neutrino-induced ones. We mainly concentrate on those properties of benchmark reactions, which are relevant to the region of Shallow Inelastic Scattering (SIS). Our results in this region are presented for integrated and differential cross sections. Comparison with recent MINOS inclusive data, as well as predictions for the differential cross sections measurable in Minerνa and NoνA experiments are made.

  15. Inelastic scattering at the B K edge of hexagonal BN

    SciTech Connect

    Jia, J.J.; Callcott, T.A.; Zhou, L.

    1997-04-01

    Many recent soft x-ray fluorescence (SXF) studies have shown that inelastic scattering processes make important contributions to the observed spectra for excitation near the x-ray threshold. These effects are all attributed to a process, usually called an electronic Raman scattering (ERS) process, in which energy is lost to an electronic excitation. The theory has been described using second order perturbation theory by Tulkki and Aberg. In different materials, the detailed nature of the electronic excitation producing the energy loss may be very different. In crystalline Si, diamond and graphite, changes in spectral shape and dispersion of spectral features with variation of the excitation energy are observed, which are attributed to k conservation between the photoelectron generated in the excitation process and the valence hole remaining after the coupled emission process. Hence the process is strongly localized in k-space. In haxagonal boron nitride, which has a lattice and band structure very similar to graphite, inelastic scattering produces very different effects on the observed spectra. Here, the inelastic losses are coupled to a strong resonant elastic scattering process, in which the intermediate state is a localized core exciton and the final state is a localized valence exciton, so that the electronic excitation is strongly localized in real rather than reciprocal space.

  16. Field-theoretical description of deep inelastic scattering

    SciTech Connect

    Geyer, B.; Robaschik, D.; Wieczorek, E.

    1980-01-01

    The most important theoretical notions concerning deep inelastic scattering are reviewed. Topics discussed are the model-independent approach, which is based on the general principles of quantum field theory, the application of quantum chromodynamics to deep inelastic scattering, approaches based on the quark--parton model, the light cone algebra, and conformal invariance, and also investigations in the framework of perturbation theory.

  17. Medical applications of neutron inelastic scattering

    NASA Astrophysics Data System (ADS)

    Kehayias, Joseph J.; Banuk-Waitekus, Anathea; Valtuena, Silvia; Sheahan, Charles A.

    1999-10-01

    A sealed, D-T, pulsed neutron generator is used for the in vivo measurement of body carbon and oxygen by neutron inelastic scattering. The generator is operated at 10 KHz, at a neutron output of about 2 X 107 n/s/4(pi) . Gamma ray spectra are collected with two B4Ge3O12 crystal detectors. The measurements are used to measure fat and lean content and distribution in the body, with minimal radiation exposure (0.08 mSv). When combined with other measurements (such as total body potassium), this whole body scanning device provides us with the `quality of lean mass', a measurable outcome of treatments designed to improve nutritional status and function. The method is used in studies of human nutrition and for assessing the efficacy of new anti-obesity and anti-cachexia pharmaceuticals.

  18. Observation of the naive-T-odd Sivers effect in deep-inelastic scattering.

    PubMed

    Airapetian, A; Akopov, N; Akopov, Z; Aschenauer, E C; Augustyniak, W; Avetissian, A; Avetisyan, E; Bacchetta, A; Ball, B; Bianchi, N; Blok, H P; Böttcher, H; Bonomo, C; Borissov, A; Bryzgalov, V; Burns, J; Capiluppi, M; Capitani, G P; Cisbani, E; Ciullo, G; Contalbrigo, M; Dalpiaz, P F; Deconinck, W; De Leo, R; De Nardo, L; De Sanctis, E; Diefenthaler, M; Di Nezza, P; Dreschler, J; Düren, M; Ehrenfried, M; Elbakian, G; Ellinghaus, F; Elschenbroich, U; Fabbri, R; Fantoni, A; Felawka, L; Frullani, S; Gabbert, D; Gapienko, G; Gapienko, V; Garibaldi, F; Gharibyan, V; Giordano, F; Gliske, S; Hadjidakis, C; Hartig, M; Hasch, D; Hill, G; Hillenbrand, A; Hoek, M; Holler, Y; Hristova, I; Imazu, Y; Ivanilov, A; Jackson, H E; Jo, H S; Joosten, S; Kaiser, R; Keri, T; Kinney, E; Kisselev, A; Korotkov, V; Kozlov, V; Kravchenko, P; Lagamba, L; Lamb, R; Lapikás, L; Lehmann, I; Lenisa, P; Linden-Levy, L A; López Ruiz, A; Lorenzon, W; Lu, X-G; Lu, X-R; Ma, B-Q; Mahon, D; Makins, N C R; Manaenkov, S I; Manfré, L; Mao, Y; Marianski, B; Martinez de la Ossa, A; Marukyan, H; Miller, C A; Miyachi, Y; Movsisyan, A; Murray, M; Mussgiller, A; Nappi, E; Naryshkin, Y; Nass, A; Negodaev, M; Nowak, W-D; Pappalardo, L L; Perez-Benito, R; Reimer, P E; Reolon, A R; Riedl, C; Rith, K; Rosner, G; Rostomyan, A; Rubin, J; Ryckbosch, D; Salomatin, Y; Sanftl, F; Schäfer, A; Schnell, G; Schüler, K P; Seitz, B; Shibata, T-A; Shutov, V; Stancari, M; Statera, M; Steijger, J J M; Stenzel, H; Stewart, J; Stinzing, F; Taroian, S; Terkulov, A; Trzcinski, A; Tytgat, M; Vandenbroucke, A; van der Nat, P B; Van Haarlem, Y; Van Hulse, C; Varanda, M; Veretennikov, D; Vikhrov, V; Vilardi, I; Vogel, C; Wang, S; Yaschenko, S; Ye, H; Ye, Z; Yen, S; Yu, W; Zeiler, D; Zihlmann, B; Zupranski, P

    2009-10-01

    Azimuthal single-spin asymmetries of leptoproduced pions and charged kaons were measured on a transversely polarized hydrogen target. Evidence for a naive-T-odd, transverse-momentum-dependent parton distribution function is deduced from nonvanishing Sivers effects for pi(+), pi(0), and K(+/-), as well as in the difference of the pi(+) and pi(-) cross sections. PMID:19905623

  19. Simple model of bulk and surface excitation effects to inelastic scattering in low-energy electron beam irradiation of multi-walled carbon nanotubes

    SciTech Connect

    Kyriakou, Ioanna; Emfietzoglou, Dimitris; Garcia-Molina, Rafael; Abril, Isabel; Kostarelos, Kostas

    2011-09-01

    The effect of bulk and surface excitations to inelastic scattering in low-energy electron beam irradiation of multi-walled carbon nanotubes (MWNTs) is studied using the dielectric formalism. Calculations are based on a semiempirical dielectric response function for MWCNTs determined by means of a many-pole plasmon model with parameters adjusted to available experimental spectroscopic data under theoretical sum-rule constrains. Finite-size effects are considered in the context of electron gas theory via a boundary correction term in the plasmon dispersion relations, thus, allowing a more realistic extrapolation of the electronic excitation spectrum over the whole energy-momentum plane. Energy-loss differential and total inelastic scattering cross sections as a function of electron energy and distance from the surface, valid over the energy range {approx}50-30,000 eV, are calculated with the individual contribution of bulk and surface excitations separated and analyzed for the case of normally incident and escaping electrons. The sensitivity of the results to the various approximations for the spatial dispersion of the electronic excitations is quantified. Surface excitations are shown to have a strong influence upon the shape and intensity of the energy-loss differential cross section in the near surface region whereas the general notion of a spatially invariant inelastic mean free path inside the material is found to be of good approximation.

  20. Inelastic x-ray scattering at modest energy resolution

    SciTech Connect

    Finkelstein, K. D.; Tischler, J. Z.; Larson, B. C.

    1997-07-01

    We report results from the development of an inelastic scattering spectrometer designed to take advantage of high energy synchrotron radiation available at CHESS. The device allows a large increase of the effective scattering volume in the sample by permitting measurements to be made in an energy range up to 25 KeV. The highest useable energy appears limited by the efficiency of the analyzers under consideration. At 20 KeV a novel 4-bounce, sagittal focusing monochromator passes 10e11 photons/second with Darwin width limited energy resolution. In the scattering plane, the monochromator images the electron beam producing a small scattering source for the analyzing optics. Analyzer systems under study include a cooled mosaic crystal in para-focusing geometry, and an adjustable spherically bent silicon crystal respectively for parallel and point-by-point collection of the energy loss spectrum. This paper discusses the optical configurations presents results from our early measurements and suggests directions for improvements.

  1. Superconducting pairing in resonant inelastic x-ray scattering

    NASA Astrophysics Data System (ADS)

    Shi, Yifei; Benjamin, David; Demler, Eugene; Klich, Israel

    2016-09-01

    We develop a method to study the effect of the superconducting transition on the resonant inelastic x-ray scattering (RIXS) signal in superconductors with an order parameter with an arbitrary symmetry within a quasiparticle approach. As an example, we compare the direct RIXS signal below and above the superconducting transition for p -wave-type order parameters. For a p -wave order parameter with a nodal line, we show that, counterintuitively, the effect of the gap is most noticeable for momentum transfers in the nodal direction. This phenomenon may be naturally explained as a type of nesting effect.

  2. Pion inelastic scattering from sup 20 Ne

    SciTech Connect

    Burlein, M. . Dept. of Physics)

    1989-12-01

    Angular distributions for {sup 20}Ne({pi}{sup {plus minus}}, {pi}{sup {plus minus}}{prime}) were measured on the Energetic Pion Channel and Spectrometer (EPICS) at the Clinton P. Anderson Meson Physics Facility (LAMPF). Data were taken with both {pi}{sup {plus}} and {pi}{sup {minus}} over an angular range of 12{degree} to 90{degree} for T{sub {pi}}=180 MeV and with {pi}{sup +} from 15{degree} to 90{degree} for T{sub {pi}}=120 MeV. The data were analyzed using both the distorted-wave impulse approximation (DWIA) and the coupled-channels impulse approximation (CCIA) with collective transition densities. In addition, microscopic transition densities were used in the DWIA analysis for states in the lowest rotational bands. The transitions to the 6.73-MeV 0{sup +} and several 1{sup {minus}} states, including the states at 5.79 MeV and 8.71 MeV, were studied using several models for the transition density. Strong evidence for the importance of two-step routes in pion inelastic scattering was seen in several angular distributions, including the 5.79-MeV 1{sup {minus}}, the first three 4{sup +} states, and the 8.78-MeV 6{sup +}. 100 refs., 81 figs., 33 tabs.

  3. In situ measurement of inelastic light scattering in natural waters

    NASA Astrophysics Data System (ADS)

    Hu, Chuanmin

    Variation in the shape of solar absorption (Fraunhofer) lines are used to study the inelastic scattering in natural waters. In addition, oxygen absorption lines near 689nm are used to study the solar stimulated chlorophyll fluorescence. The prototype Oceanic Fraunhofer Line Discriminator (OFLD) has been further developed and improved by using a well protected fiber optic - wire conductor cable and underwater electronic housing. A Monte-Carlo code and a simple code have been modified to simulate the Raman scattering, DOM fluorescence and chlorophyll fluorescence. A series of in situ measurements have been conducted in clear ocean waters in the Florida Straits, in the turbid waters of Florida Bay, and in the vicinity of a coral reef in the Dry Tortugas. By comparing the reduced data with the model simulation results, the Raman scattering coefficient, b r with an excitation wavelength at 488nm, has been verified to be 2.6 × 10-4m-1 (Marshall and Smith, 1990), as opposed to 14.4 × 10- 4m-1 (Slusher and Derr, 1975). The wavelength dependence of b r cannot be accurately determined from the data set as the reported values (λ m-4 to λ m- 5) have an insignificant effect in the natural underwater light field. Generally, in clear water, the percentage of inelastic scattered light in the total light field at /lambda < 510nm is negligible for the whole water column, and this percentage increases with depth at /lambda > 510nm. At low concentrations (a y(/lambda = 380nm) less than 0.1m-1), DOM fluorescence plays a small role in the inelastic light field. However, chlorophyll fluorescence is much stronger than Raman scattering at 685nm. In shallow waters where a sea bottom affects the ambient light field, inelastic light is negligible for the whole visible band. Since Raman scattering is now well characterized, the new OFLD can be used to measure the solar stimulated in situ fluorescence. As a result, the fluorescence signals of various bottom surfaces, from coral to

  4. Elastic and inelastic scattering of He atoms from Bi(111)

    NASA Astrophysics Data System (ADS)

    Tamtögl, A.; Mayrhofer-Reinhartshuber, M.; Balak, N.; Ernst, W. E.; Rieder, K. H.

    2010-08-01

    Elastic and inelastic scattering of helium atoms has been used to study the Bi(111) surface. Sharp diffraction peaks are found with results in excellent agreement with previous structure determinations of the Bi(111) surface. The rather large first order peaks with respect to the zero order peak indicate a stronger surface corrugation than observed in helium scattering from other metallic surfaces. Time-of-flight spectra of scattered He atoms clearly reveal two inelastic scattering maxima, which allow a first report on phonon creation and annihilation events on the Bi(111) surface. An estimate of the group velocity shows that the phonon creation peak is likely to correspond to a Rayleigh mode.

  5. Elastic and inelastic scattering of neutrons on 238U nucleus

    NASA Astrophysics Data System (ADS)

    Capote, R.; Trkov, A.; Sin, M.; Herman, M. W.; Soukhovitskiĩ, E. Sh.

    2014-04-01

    Advanced modelling of neutron induced reactions on the 238U nucleus is aimed at improving our knowledge of neutron scattering. Capture and fission channels are well constrained by available experimental data and neutron standard evaluation. A focus of this contribution is on elastic and inelastic scattering cross sections. The employed nuclear reaction model includes - a new rotational-vibrational dispersive optical model potential coupling the low-lying collective bands of vibrational character observed in even-even actinides; - the Engelbrecht-Weidenmüller transformation allowing for inclusion of compound-direct interference effects; - and a multi-humped fission barrier with absorption in the secondary well described within the optical model for fission. Impact of the advanced modelling on elastic and inelastic scattering cross sections including angular distributions and emission spectra is assessed both by comparison with selected microscopic experimental data and integral criticality benchmarks including measured reaction rates (e.g. JEMIMA, FLAPTOP and BIG TEN). Benchmark calculations provided feedback to improve the reaction modelling. Improvement of existing libraries will be discussed.

  6. Quantum chromodynamics and deep-inelastic scattering

    SciTech Connect

    Buras, A.J.

    1980-08-01

    Moments of deep-inelastic structure functions, parton distributions and parton fragmentation functions are discussed in the context of Quantum Chromodynamics with particular emphasis put on higher order corrections. A brief discussion of higher twist contributions is also given.

  7. Focusing polycapillary to reduce parasitic scattering for inelastic x-ray measurements at high pressure

    SciTech Connect

    Chow, P. Xiao, Y. M.; Rod, E.; Bai, L. G.; Shen, G. Y.; Sinogeikin, S.; Gao, N.; Ding, Y.; Mao, H.-K.

    2015-07-15

    The double-differential scattering cross-section for the inelastic scattering of x-ray photons from electrons is typically orders of magnitude smaller than that of elastic scattering. With samples 10-100 μm size in a diamond anvil cell at high pressure, the inelastic x-ray scattering signals from samples are obscured by scattering from the cell gasket and diamonds. One major experimental challenge is to measure a clean inelastic signal from the sample in a diamond anvil cell. Among the many strategies for doing this, we have used a focusing polycapillary as a post-sample optic, which allows essentially only scattered photons within its input field of view to be refocused and transmitted to the backscattering energy analyzer of the spectrometer. We describe the modified inelastic x-ray spectrometer and its alignment. With a focused incident beam which matches the sample size and the field of view of polycapillary, at relatively large scattering angles, the polycapillary effectively reduces parasitic scattering from the diamond anvil cell gasket and diamonds. Raw data collected from the helium exciton measured by x-ray inelastic scattering at high pressure using the polycapillary method are compared with those using conventional post-sample slit collimation.

  8. Optical potentials for inelastic scattering from many-body targets.

    PubMed

    Cederbaum, L S

    2000-10-01

    The standard text book Green's function possesses a self-energy that is known to be an optical potential for elastic scattering. The introduction of an optical potential reduces the complex many-body scattering problem into a tractable one-body problem. In this paper inelastic Green's functions are introduced and discussed which possess self-energies that are optical potentials for inelastic scattering. If the projectile is indistinguishable from particles comprising the target, intriguing aspects arise even for noninteracting particles. PMID:11019269

  9. Dynamic color screening in diffractive deep inelastic scattering

    NASA Astrophysics Data System (ADS)

    Ingelman, Gunnar; Pasechnik, Roman; Werder, Dominik

    2016-05-01

    We present a novel Monte Carlo implementation of dynamic color screening via multiple exchanges of semisoft gluons as a basic QCD mechanism to understand diffractive electron-proton scattering at the HERA collider. Based on the kinematics of individual events in the standard QCD description of deep inelastic scattering at the parton level, which at low x is dominantly gluon initiated, the probability is evaluated for additional exchanges of softer gluons resulting in an overall color singlet exchange leading to a forward proton and a rapidity gap as the characteristic observables for diffractive scattering. The probability depends on the impact parameter of the soft exchanges and varies with the transverse size of the hard scattering subsystem and is therefore influenced by different QCD effects. We account for matrix elements and parton shower evolution either via conventional DGLAP log Q2 evolution with collinear factorization or CCFM small x evolution with k⊥ factorization and discuss the sensitivity to the gluon density distribution in the proton and the importance of large log x contributions. The overall result is, with only two model parameters which have theoretically motivated values, a satisfactory description of the observed diffractive cross section at HERA obtained in a wide kinematical range.

  10. Inelastic x-ray scattering at modest energy resolution

    SciTech Connect

    Finkelstein, K.D.; Larson, B.C.

    1997-07-01

    We report results from the development of an inelastic scattering spectrometer designed to take advantage of high energy synchrotron radiation available at CHESS. The device allows a large increase of the effective scattering volume in the sample by permitting measurements to be made in an energy range up to 25 KeV. The highest useable energy appears limited by the efficiency of the analyzers under consideration. At 20 KeV a novel 4-bounce, sagittal focusing monochromator passes 10e11 photons/second with Darwin width limited energy resolution. In the scattering plane, the monochromator images the electron beam producing a small scattering source for the analyzing optics. Analyzer systems under study include a cooled mosaic crystal in para-focusing geometry, and an adjustable spherically bent silicon crystal respectively for parallel and point-by-point collection of the energy loss spectrum. This paper discusses the optical configurations presents results from our early measurements and suggests directions for improvements. {copyright} {ital 1997 American Institute of Physics.}

  11. Particle production at small-x in deep inelastic scattering

    NASA Astrophysics Data System (ADS)

    Wu, Dajing

    The properties of small-x QCD are studied in this dissertation. One of the most interesting features of small-x physics is gluon saturation effect and to obtain direct evidence of this effect has been of great theoretical and experimental interest. We focus on deep inelastic scattering off heavy nucleus which may provide the first evidence of gluon saturation. Our results might be put into test in future by Electron-Ion Collider(EIC). We studied transverse momentum spectrum in gluon production and analyzed the result in different regimes of nuclear matter, dilute nucleus and saturated nucleus included. We first studied diffractive gluon production in small- x DIS, which itself is an excellent probe to detect gluon distribution inside nucleus. We then made an investigation on inclusive gluon production in DIS and, specifically, tried to understand the contribution from momentum conservation.

  12. A model independent approach to inelastic dark matter scattering

    NASA Astrophysics Data System (ADS)

    Barello, G.; Chang, Spencer; Newby, Christopher A.

    2014-11-01

    We present a model independent analysis of inelastic dark matter transitions at direct detection experiments by modifying the elastic methodology of Fitzpatrick et al. By analyzing the kinematics of inelastic transitions, we find the relevant variables to describe these scattering processes, the primary change being a modification of the v→⊥ variable. Taking this into account, we list the relevant scattering matrix elements and modify the Mathematica package of Anand et al. to calculate the necessary form factors. As an application, we determine the matrix elements of inelastic scattering for spin transitions between a fermion to fermion, scalar to vector, and scalar to scalar. Finally, we consider fits to the DAMA/LIBRA annual modulation signal for the magnetic inelastic dark matter scenario as well as a model independent scan over relativistic operators, constraining them with limits from direct detection experiments. In the magnetic inelastic dark matter scenario or if the dark matter couples through relativistic operators involving only protons, we find that experiments with xenon and germanium targets can have consistently small rates. However, limits from iodine experiments are much more constraining, leaving small regions of allowed parameter space. We point out that existing uncertainties in the iodine quenching factor strongly affects the constraints, motivating further study to pin down the correct values.

  13. Energy dependence of pion inelastic scattering from sup 208 Pb

    SciTech Connect

    Oakley, D.S. Lewis and Clark College, Portland, Oregon ); Peterson, R.J. ); Seestrom, S.J.; Morris, C.L.; Plum, M.A. ); Zumbro, J.D. ); Williams, A.L.; Bryan, M.A.; McDonald, J.W.; Moore, C.F. )

    1991-11-01

    Differential cross sections were measured for pion elastic and inelastic scattering from {sup 208}Pb at {ital T}{sub {pi}}=120 and 250 MeV. Energy-dependent neutron- and proton-transition matrix elements for a range of excited states were extracted and tested for consistency, using several structure models.

  14. Benchmarking the inelastic neutron scattering soil carbon method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The herein described inelastic neutron scattering (INS) method of measuring soil carbon was based on a new procedure for extracting the net carbon signal (NCS) from the measured gamma spectra and determination of the average carbon weight percent (AvgCw%) in the upper soil layer (~8 cm). The NCS ext...

  15. In-situ soil carbon analysis using inelastic neutron scattering

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In situ soil carbon analysis using inelastic neutron scattering (INS) is based on the emission of 4.43 MeV gamma rays from carbon nuclei excited by fast neutrons. This in-situ method has excellent potential for easily measuring soil carbon since it does not require soil core sampling and processing ...

  16. Inelastic neutron scattering from carbon, iron, yttrium and lead

    NASA Astrophysics Data System (ADS)

    Gustavsson, Cecilia; Blomgren, Jan; Hellesen, Carl; Öhrn, Angelica; Pomp, Stephan

    2012-02-01

    Double-differential cross sections and angular distributions of inelastic neutron scattering on 12C, 56Fe, 89Y and 208Pb have been measured at 96 MeV at The Svedberg Laboratory, Uppsala, Sweden. Results on elastic neutron scattering at 96 MeV from these nuclei have been reported previously [1-3]. To obtain the inelastic cross sections, a forward-folding technique has been applied. A physically reasonable trial spectrum has been folded with the response function of the detector system and the output has been compared with the experimental data. To create the trial spectrum, a Gaussian has been used for the elastic part and the PRECO code [4-7] for the inelastic part. Other models were tested for the pre-equilibrium contribution and the method was found to be model independent. The response function of the detector setup has been obtained experimentally at the smallest possible angle, in this case at 9 deg. The resulting preliminary inelastic scattering data cover an excitation energy range up to 45 MeV and the angular intervals 28 to 58 degrees for 12C, 26 to 65 degrees for 56Fe and 26 to 52 degrees for 89Y and 208Pb. The preliminary results are discussed and compared to several model codes as well as existing experimental data for (n,n'x), (n,p'x) and (p,p'x). Possible improvements of the analysis are also discussed.

  17. Inelastic x-ray scattering from polycrystalline materials at low momentum transfer

    SciTech Connect

    Bosak, Alexey; Krisch, Michael; Fischer, Irmengard; Huotari, Simo; Monaco, Giulio

    2007-02-01

    The inelastic x-ray scattering from polycrystalline materials at low momentum transfer is analyzed with respect to the orientation-averaged acoustic phonon dispersion and the relationship between the derived sound velocities and their corresponding macroscopic entities. The effect of texturing on the sound dispersion is discussed and illustrated using the examples of hcp cobalt and hexagonal graphite. Our theoretical considerations are supported by experimental results and emphasize the importance to carefully consider the effects of elastic anisotropy when data obtained by inelastic x-ray scattering are compared or confronted with macroscopic measurements.

  18. Solar-stimulated inelastic light scattering in clear seawater

    NASA Astrophysics Data System (ADS)

    Hu, Chuanmin; Voss, Kenneth J.

    1997-02-01

    Solar Fraunhofer lines are used as indicators of the inelastic light scattering in the sea water. Data from both in-shore and off-shore are presented and compared with results of theoretical modeling. Very good agreement is found between the modeled and measured proportion of inelastic to elastically scattered and direct light at 589 nm when the Raman scattering coefficient of Marshall and Smith is used, as opposed to that of Slusher and Derr. At 656 nm the agreement is not as good, indicating possible interference from other sources such a Chlorophyll fluorescence. Recent work has extended the measurements of include smaller absorption lines, such as 689 nm, where significant filling has been measured at the surface due to the Chlorophyll fluorescence. This technique allows the natural fluorescence to be measured, even at the surface where there is still a significant amount of direct solar light.

  19. DEEPLY INELASTIC SCATTERING OFF NUCLEI AT RHIC.

    SciTech Connect

    VENUGOPALAN, R.

    2001-09-14

    In this talk, we discussed the physics case for an eA collider. We emphasized the novel physics that might be studied at small x. The interesting physics at intermediate x's has been discussed elsewhere [3]. Plans for an electron-ion collider include, as a major part of the program, the possibility of doing polarized electron-polarized proton/light ion scattering. A discussion of the combined case for high energy electron nucleus and polarized electron-polarized proton scattering will be published separately [66].

  20. Conversion method of powder inelastic scattering data for one-dimensional systems

    SciTech Connect

    Tomiyasu, Dr. Keisuke; Fujita, Prof. Masaki; Kolesnikov, Alexander I; Bewley, Robert I.; Bull, Dr. Martyn J.; Bennington, Dr. Stephen M.

    2009-01-01

    Extracting dispersive magnetic excitations from inelastic neutron scattering data usually requires large single crystals. We present a simple yet powerful method for extracting such information from polycrystalline or powder data for one-dimensional systems. We demonstrate the effectiveness of this data treatment by extracting dispersion curves from powder inelastic neutron scattering data on the one-dimensional spin-half systems: CuGeO3 and Rb2Cu2Mo3O12. For many such materials it is not possible to grow sufficiently large crystals and this method offers a quick and efficient way to study their magnetic excitations.

  1. Measurement of proton inelastic scattering cross sections on fluorine

    NASA Astrophysics Data System (ADS)

    Chiari, M.; Caciolli, A.; Calzolai, G.; Climent-Font, A.; Lucarelli, F.; Nava, S.

    2016-10-01

    Differential cross-sections for proton inelastic scattering on fluorine, 19F(p,p')19F, from the first five excited levels of 19F at 110, 197, 1346, 1459 and 1554 keV were measured for beam energies from 3 to 7 MeV at a scattering angle of 150° using a LiF thin target (50 μg/cm2) evaporated on a self-supporting C thin film (30 μg/cm2). Absolute differential cross-sections were calculated with a method not dependent on the absolute values of collected beam charge and detector solid angle. The validity of the measured inelastic scattering cross sections was then tested by successfully reproducing EBS spectra collected from a thick Teflon (CF2) target. As a practical application of these measured inelastic scattering cross sections in elastic backscattering spectroscopy (EBS), the feasibility of quantitative light element (C, N and O) analysis in aerosol particulate matter samples collected on Teflon by EBS measurements and spectra simulation is demonstrated.

  2. Modern Techniques for Inelastic Thermal Neutron Scattering Analysis

    NASA Astrophysics Data System (ADS)

    Hawari, A. I.

    2014-04-01

    A predictive approach based on ab initio quantum mechanics and/or classical molecular dynamics simulations has been formulated to calculate the scattering law, S(κ⇀,ω), and the thermal neutron scattering cross sections of materials. In principle, these atomistic methods make it possible to generate the inelastic thermal neutron scattering cross sections of any material and to accurately reflect the physical conditions of the medium (i.e, temperature, pressure, etc.). In addition, the generated cross sections are free from assumptions such as the incoherent approximation of scattering theory and, in the case of solids, crystalline perfection. As a result, new and improved thermal neutron scattering data libraries have been generated for a variety of materials. Among these are materials used for reactor moderators and reflectors such as reactor-grade graphite and beryllium (including the coherent inelastic scattering component), silicon carbide, cold neutron media such as solid methane, and neutron beam filters such as sapphire and bismuth. Consequently, it is anticipated that the above approach will play a major role in providing the nuclear science and engineering community with its needs of thermal neutron scattering data especially when considering new materials where experimental information may be scarce or nonexistent.

  3. Neutron inelastic scattering spectrum of footballene C{sub 60}

    SciTech Connect

    Coulombeau, C.; Jobic, H.; Bernier, P.

    1992-01-09

    The authors report results of a neutron inelastic scattering study of C{sub 60}. They prepared a 1.63 g sample, and using the ISIS pulsed neutron source at the Rutherford Appleton Laboratory, obtained spectral scans at 25K using a crystal analyzer. Of the 46 calculated nondegenerate frequencies in the vibrational spectrum, they have located 28 of them, including all the optically observed lines.

  4. Jet production in deep inelastic scattering at HERA

    SciTech Connect

    Sutton, M. R.

    2006-04-11

    A number of the most recent results from the wealth of precision HERA data on high transverse energy jet production in deep inelastic scattering are reviewed. These measurements are confronted with predictions from next-to-leading order (NLO) Quantum Chromodynamics and allow the extraction of the strong coupling constant, {alpha}s, and have been used in QCD fits of the parton distribution functions in the proton.

  5. UB Matrix Implementation for Inelastic Neutron Scattering Experiments

    SciTech Connect

    Lumsden, Mark D; Robertson, Lee; Yethiraj, Mohana

    2005-01-01

    The UB matrix approach has been extended to handle inelastic neutron scattering experiments with differing k{sub i} and k{sub f}. We have considered the typical goniometer employed on triple-axis and time-of-flight spectrometers. Expressions are derived to allow for calculation of the UB matrix and for converting from observables to Q-energy space. In addition, we have developed appropriate modes for calculation of angles for a specified Q-energy position.

  6. Alpha inelastic scattering and cluster structures in {sup 24}Mg

    SciTech Connect

    Kawabata, T.; Ishiguro, Y.; Nozawa, Y.; Tomida, N.; Yokota, N.; Adachi, T.; Fujiwara, M.; Hatanaka, K.; Tamii, A.; Yasuda, Y.; Zenihiro, J.; Itoh, M.; Takahashi, T.; Yoshida, H. P.; Maeda, Y.; Miyasako, H.; Saito, T.; Matsubara, H.; Sasamoto, Y.; Tokieda, H.

    2011-05-06

    The alpha inelastic scattering from {sup 24}Mg was measured to obtain the isoscalar natural-parity excitation strengths and to search for the {alpha}-condensed states. The multipole decomposition analysis for the measured cross sections was performed. The strength distributions for the {Delta}L = 0-3 were successfully obtained and the possible candidates for the {alpha}-condensed states around the {sup 16}O core were found.

  7. Resonant Inelastic X-ray Scattering in Correlated Electron Systems

    NASA Astrophysics Data System (ADS)

    Kim, Young-June

    2006-03-01

    Extremely bright photons generated at the new generation of synchrotron light sources have made a huge impact on various scientific disciplines ranging from biology to materials science. One of the exciting new developments is the use of x-rays in the field of solid-state spectroscopy. Inelastic x-ray scattering, analogous to the well-known inelastic neutron scattering, is a powerful tool for studying momentum-dependent electronic excitations and phonons. In particular, resonant inelastic x-ray scattering in the hard x-ray regime has been widely utilized to study the momentum dependence of various electronic excitations in strongly correlated electron systems. For example, by tuning the incident photon energy to the Cu K-edge, one can gain a large intensity enhancement as well as element specific knowledge of the electronic excitations in various copper oxide compounds. Most of the work to date has been focused on the charge-transfer excitation between the bonding and antibonding molecular orbitals, the excitation across the Mott gap, and crystal field excitations between the d-orbitals. Recent improvements in instrumentation have allowed us to observe a new mode in the mid-infrared frequency region. We will discuss the momentum dependence of these excitations in prototypical cuprate superconductors, La2-xSrxCuO4, and also examine the evolution of such excitations as charge carriers are doped into the system.

  8. Resonant inelastic x-ray scattering in a Mott insulator

    NASA Astrophysics Data System (ADS)

    Pakhira, Nandan; Freericks, J. K.; Shvaika, A. M.

    2012-09-01

    We calculate the resonant inelastic x-ray scattering (RIXS) response in a Mott insulator, which is described by the Falicov-Kimball model. The model can be solved exactly within the single site dynamical mean-field theory (DMFT) approximation and the RIXS response can also be calculated accurately up to a local background correction. We find that on resonance the RIXS response is greatly enhanced. The response systematically evolves from a single-peak structure, arising due to relaxation processes within the lower Hubbard band, to a two-peak structure, arising due to relaxation processes within the upper Hubbard band and across the Mott gap into the lower Hubbard band. This occurs as we vary the incident photon frequency to allow excitations from the lower Hubbard band to the upper Hubbard band. The charge transfer excitations are found to disperse monotonically as we go from the center of the Brillouin zone towards the zone corner. These correlation-induced features have been observed by Hasan [Science0036-807510.1126/science.288.5472.1811 288, 1811 (2000)] and many other experimentalists in RIXS measurements over various transition-metal oxide compounds. They are found to be robust and survive even for large Auger lifetime broadening effects that can mask the many-body effects by smearing out spectral features. As a comparison, we also calculate the dynamic structure factor for this model, which is proportional to the nonresonant part of the response, and does not show these specific signatures.

  9. Ultrathin aluminum sample cans for single crystal inelastic neutron scattering

    SciTech Connect

    Stone, Matthew B; Loguillo, Mark; Abernathy, Douglas L

    2011-01-01

    Single crystal inelastic neutron scattering measurements are often performed using a sample environment for controlling sample temperature. One difficulty associated with this is establishing appropriate thermal coupling from the sample to the temperature controlled portion of the sample environment. This is usually accomplished via a sample can which thermally couples the sample environment to the sample can and the sample can to the sample via an exchange gas. Unfortunately, this can will contribute additional background signal to ones measurement. We present here the design of an ultrathin aluminum sample can based upon established technology for producing aluminum beverage cans. This design minimizes parasitic sample can scattering. Neutron scattering measurements comparing a machined sample can to our beverage can design clearly indicate a large reduction in scattering intensity and texture when using the ultrathin sample can design. We also examine the possibility of using standard commercial beverage cans as sample cans.

  10. Ultrathin aluminum sample cans for single crystal inelastic neutron scattering

    NASA Astrophysics Data System (ADS)

    Stone, M. B.; Loguillo, M. J.; Abernathy, D. L.

    2011-05-01

    Single crystal inelastic neutron scattering measurements are often performed using a sample environment for controlling sample temperature. One difficulty associated with this is establishing appropriate thermal coupling from the sample to the temperature controlled portion of the sample environment. This is usually accomplished via a sample can which thermally couples the sample environment to the sample can and the sample can to the sample via an exchange gas. Unfortunately, this can will contribute additional background signal to one's measurement. We present here the design of an ultrathin aluminum sample can based upon established technology for producing aluminum beverage cans. This design minimizes parasitic sample can scattering. Neutron scattering measurements comparing a machined sample can to our beverage can design clearly indicate a large reduction in scattering intensity and texture when using the ultrathin sample can design. We also examine the possibility of using standard commercial beverage cans as sample cans.

  11. Resource Letter on Stimulated Inelastic X-ray Scattering at an XFEL

    SciTech Connect

    Patterson, Bruce D.; /SLAC

    2010-09-02

    At sufficient X-ray intensity, stimulated effects in inelastic scattering will become important. These coherent, non-linear optical phenomena may be used to impulsively produce a high degree of collective excitation in, for example, correlated electron materials, suitable for performing ultrafast time-resolved spectroscopy. This Resource Letter collects information on fundamental aspects of stimulated X-ray scattering and evaluates the prospect for successful experiments at a present or future X-ray free electron laser (XFEL) facility.

  12. Inelastic pion scattering by /sup 13/C at low energies

    SciTech Connect

    Mitchell, J.H.

    1987-03-01

    Angular distributions for inelastically scattered pions were obtained for several states in /sup 13/C at an incident energy of 65 MeV. The data include results from both ..pi../sup +/ and ..pi../sup -/ measurements. In addition, ..pi../sup -/ measurements were made at T/sub ..pi../ = 50 MeV at one angle to give a two point fixed-q excitation function. The data are compared to theory and the data of others. As might be expected, medium corrections are shown to be considerably more important at low energies than at resonance. This is true for inelastic transitions of multipolarity 0,2 and 3. Parameters derived from an analysis of elastic pion scattering and SCX data also provide an adequate description of the inelastic transitions. The charge asymmetry in the cross sections for the 9/2/sup +/ state that was seen at resonance persists at these energies. This result is consistent with an impulse approximation treatment of the spin-flip amplitude. This is true even though the incoming energy of the pions is far below the range where the validity of an impulse treatment is expected. 65 refs., 45 figs.

  13. Effect of magnetism on lattice dynamics in SrFe2As2 using high-resolution inelastic x-ray scattering

    NASA Astrophysics Data System (ADS)

    Murai, N.; Fukuda, T.; Kobayashi, T.; Nakajima, M.; Uchiyama, H.; Ishikawa, D.; Tsutsui, S.; Nakamura, H.; Machida, M.; Miyasaka, S.; Tajima, S.; Baron, A. Q. R.

    2016-01-01

    Phonon spectra of detwinned SrFe2As2 crystals, as measured by inelastic x-ray scattering, show clear anisotropy accompanying the magnetostructural transition at 200 K. We model the mode splitting using magnetic DFT calculations, including a phenomenological reduction in force-constant anisotropy that can be attributed to magnetic fluctuations. This serves as a starting point for a general model of phonons in this material applicable to both the antiferromagnetically ordered phase and the paramagnetic phase. Using this model, the measured splitting in the magnetic phase below TN, and the measured phonon linewidth, we set a lower bound on the mean magnetic fluctuation frequency above TN at 210 K.

  14. Elastic and Inelastic Scattering of Neutrons using a CLYC array

    NASA Astrophysics Data System (ADS)

    Brown, Tristan; Doucet, E.; Chowdhury, P.; Lister, C. J.; Wilson, G. L.; Devlin, M.; Mosby, S.

    2015-10-01

    CLYC scintillators, which have dual neutron and gamma response, have recently ushered in the possibility of fast neutron spectroscopy without time-of-flight (TOF). A 16-element array of 1'' x 1'' 6Li-depleted CLYC crystals, where pulse-shape-discrimination is achieved via digital pulse processing, has been commissioned at UMass Lowell. In an experiment at LANSCE, high energy neutrons were used to bombard 56Fe and 238U targets, in order to measure elastic and inelastic neutron scattering cross sections as a function of energy and angle with the array. The array is placed very close to the targets for enhanced geometrical solid angles for scattered neutrons compared to standard neutron-TOF measurements. A pulse-height spectrum of scattered neutrons in the detectors is compared to the energy of the incident neutrons, which is measured via the TOF of the pulsed neutrons from the source to the detectors. Recoil corrections are necessary to combine the energy spectra from all the detectors to obtain angle-integrated elastic and inelastic cross-sections. The detection techniques, analysis procedures and results will be presented. Supported by NNSA-SSAA program through DOE Grant DE-NA00013008.

  15. Studies of toxic aerosols via elastic and inelastic light scattering

    SciTech Connect

    Foss, W.; Li, W.; Allen, T.M.; Blair, D.S.; Davis, E.J. )

    1993-02-01

    Evaporation rates and chemical characteristics of potentially toxic aerosols have been determined by elastic and inelastic light-scattering measurements. The aerosol systems examined were a commercial catalyst consisting of a mixture of stannous octanoate (SNO) and 2-ethylhexanoic acid (EHA) and droplets emitted from open tanks of chromic acid solutions used for anodizing aluminum. The heavy metals contained in these aerosols represent a danger to the workplace if such materials are inhaled. Nanogram amounts of the solutions were studied by suspending single microdroplets in electrodynamic balances in a flow of air to measure evaporation rates and to obtain Raman spectra. Elastic scattering data include phase functions and morphological resonance spectra from which droplet sizes are determined. The inelastic light-scattering data or Raman spectra provide molecular vibrational bond information. It was found that EHA spectra agree with bulk data in the literature, and that SNO Raman spectra, which are not available in the literature, are consistent with infrared spectra for bulk SNO. At room temperature the vapor pressure of SNO is on the order of 0.01 Pa while that of EHA is on the order of 0.1 Pa. Raman data for the residue of evaporated chromic acid solutions show the presence of chromium oxides (Cr[sup 6+] compounds), surfactants, and bound (nonvolatile) water. 31 refs., 14 figs.

  16. Rotationally inelastic gas--surface scattering: HCl from Au(111)

    SciTech Connect

    Lykke, K.R.; Kay, B.D. )

    1990-02-15

    A quantum-resolved molecular beam--surface scattering study of HCl scattered from Au(111) is described. The HCl is detected in a quantum-resolved manner via (2+1) resonant enhanced multiphoton ionization (REMPI). Greater than 85% of the incident HCl molecules are in a single-quantum state ({ital v}=0, {ital J}=0) with a narrow velocity distribution ({Delta}{upsilon}/{upsilon}{lt}0.10). The scattered HCl is strongly peaked about the specular angle, and both its final velocity and rotational distributions are indicative of direct inelastic scattering. The scattered rotational distributions exhibit features characteristic of rotational rainbows and have a mean rotational energy that displays a bilinear dependence upon the incident normal kinetic energy and surface temperature. The final velocity distributions are largely insensitive to the rotational level and indicate that the energy loss to phonons is small ({lt}20%). Analysis of the scattered data indicates an orientation-averaged attractive well depth of {similar to}5 kcal/mol for the HCl--Au(111) interaction.

  17. Reprint of : Photon correlations generated by inelastic scattering in a one-dimensional waveguide coupled to three-level systems

    NASA Astrophysics Data System (ADS)

    Fang, Yao-Lung L.; Baranger, Harold U.

    2016-08-01

    We study photon correlations generated by scattering from three-level systems (3LS) in one dimension. The two systems studied are a 3LS in a semi-infinite waveguide (3LS plus a mirror) and two 3LS in an infinite waveguide (double 3LS). Our two-photon scattering approach naturally connects photon correlation effects with inelastically scattered photons; it corresponds to input-output theory in the weak-probe limit. At the resonance where electromagnetically induced transparency (EIT) occurs, we find that no photons are scattered inelastically and hence there are no induced correlations. Slightly away from EIT, the total inelastically scattered flux is large, being substantially enhanced due to the additional interference paths. This enhancement carries over to the two-photon correlation function, which exhibits non-classical behavior such as strong bunching with a very long time-scale. The long time scale originates from the slow-light effect associated with EIT.

  18. Photon correlations generated by inelastic scattering in a one-dimensional waveguide coupled to three-level systems

    NASA Astrophysics Data System (ADS)

    Fang, Yao-Lung L.; Baranger, Harold U.

    2016-04-01

    We study photon correlations generated by scattering from three-level systems (3LS) in one dimension. The two systems studied are a 3LS in a semi-infinite waveguide (3LS plus a mirror) and two 3LS in an infinite waveguide (double 3LS). Our two-photon scattering approach naturally connects photon correlation effects with inelastically scattered photons; it corresponds to input-output theory in the weak-probe limit. At the resonance where electromagnetically induced transparency (EIT) occurs, we find that no photons are scattered inelastically and hence there are no induced correlations. Slightly away from EIT, the total inelastically scattered flux is large, being substantially enhanced due to the additional interference paths. This enhancement carries over to the two-photon correlation function, which exhibits non-classical behavior such as strong bunching with a very long time-scale. The long time scale originates from the slow-light effect associated with EIT.

  19. Inelastic X-ray Scattering from Shocked Liquid Deuterium

    SciTech Connect

    Regan, S. P.; Falk, K.; Gregori, G.; Radha, P. B.; Hu, S. X.; Boehly, T. R.; Crowley, B.; Glenzer, S. H.; Landen, O.; Gericke, D. O.; Doeppner, T.; Meyerhofer, D. D.; Murphy, C. D.; Sangster, T. C.; Vorberger, J.

    2012-12-28

    The Fermi-degenerate plasma conditions created in liquid deuterium by a laser-ablation—driven shock wave were probed with noncollective, spectrally resolved, inelastic x-ray Thomson scattering employing Cl Lyα line emission at 2.96 keV. Thus, these first x-ray Thomson scattering measurements of the microscopic properties of shocked deuterium show an inferred spatially averaged electron temperature of 8±5 eV, an electron density of 2.2(±0.5)×1023 cm-3, and an ionization of 0.8 (-0.25, +0.15). Our two-dimensional hydrodynamic simulations using equation-of-state models suited for the extreme parameters occurring in inertial confinement fusion research and planetary interiors are consistent with the experimental results.

  20. Inelastic X-ray Scattering from Shocked Liquid Deuterium

    DOE PAGESBeta

    Regan, S. P.; Falk, K.; Gregori, G.; Radha, P. B.; Hu, S. X.; Boehly, T. R.; Crowley, B.; Glenzer, S. H.; Landen, O.; Gericke, D. O.; et al

    2012-12-28

    The Fermi-degenerate plasma conditions created in liquid deuterium by a laser-ablation—driven shock wave were probed with noncollective, spectrally resolved, inelastic x-ray Thomson scattering employing Cl Lyα line emission at 2.96 keV. Thus, these first x-ray Thomson scattering measurements of the microscopic properties of shocked deuterium show an inferred spatially averaged electron temperature of 8±5 eV, an electron density of 2.2(±0.5)×1023 cm-3, and an ionization of 0.8 (-0.25, +0.15). Our two-dimensional hydrodynamic simulations using equation-of-state models suited for the extreme parameters occurring in inertial confinement fusion research and planetary interiors are consistent with the experimental results.

  1. Inelastic Proton Scattering on 21Na in Inverse Kinematics

    NASA Astrophysics Data System (ADS)

    Austin, Roby

    2009-10-01

    R.A.E. Austin, R. Kanungo, S. Reeve, Saint Mary's University; D.G. Jenkins, C.Aa.Diget, A. Robinson, A.G. Tuff, O. Roberts, University of York, UK; P.J. Woods, T. Davinson, G. J. Lotay, University of Edinburgh; C.-Y. Wu, Lawrence Livermore National Laboratory; H. Al Falou, G.C. Ball, M. Djongolov, A. Garnsworthy, G. Hackman, J.N. Orce, C.J. Pearson, S. Triambak, S.J. Williams, TRIUMF; C. Andreiou, D.S. Cross, N. Galinski, R. Kshetri, Simon Fraser University; C. Sumithrarachchi, M.A. Schumaker, University of Guelph; M.P. Jones, S.V. Rigby, University of Liverpool; D. Cline, A. Hayes, University of Rochester; T.E. Drake, University of Toronto; We describe an experiment and associated technique [1] to measure resonances of interest in astrophysical reactions. At the TRIUMF ISAC-II radioactive beam accelerator facility in Canada, particles inelastically scattered in inverse kinematics are detected with Bambino, a δE-E silicon telescope spanning 15-40 degrees in the lab. We use the TIGRESS to detect gamma rays in coincidence with the charged particles to cleanly select inelastic scattering events. We measured resonances above the alpha threshold in ^22Mg of relevance to the rate of break-out from the hot-CNO cycle via the reaction ^ 18Ne(α,p)^21Na. [1] PJ Woods et al. Rex-ISOLDE proposal 424 Cern (2003).

  2. Inelastic proton scattering of Sn isotopes studied with GRETINA

    NASA Astrophysics Data System (ADS)

    Campbell, Christopher

    2014-03-01

    The chain of semi-magic Sn nuclei, with many stable isotopes, has been a fertile ground for experimental and theoretical studies. Encompassing a major neutron shell from N = 50 to 82, the properties and structure of these nuclei provided important data for the development of the pairing-plus-quadrupole model. Recent experimental information on B(E2) for 106,108,110,112Sn came as a surprise as it indicated a larger collectivity than the predicted parabolic trend of quadrupole collectivity. These data, instead, show an unexpectedly flat trend even as the number of valence particles is reduced from 12 to 6. To fully understand how collectivity is evolving in these isotopes, 108,110,112Sn have been studied using thick-target, inelastic proton scattering with GRETINA tagging inelastic scattering events by detecting gamma-rays from the prompt decay of states excited in the reaction. We will present the trend of 2 + excitation cross-sections, the deduced quadrupole deformation parameters, and observations of other low-lying collective states. Comparison of these (p,p') quadrupole deformation parameters with B(E2) data will provide new insights into the relative importance of proton and neutron contributions to collectivity in these nuclei. GRETINA was funded by the US DOE - Office of Science. Operation of the array at NSCL is supported by NSF under Cooperative Agreement PHY-1102511(NSCL) and DOE under grant DE-AC02-05CH11231(LBNL).

  3. Experimental measurements with Monte Carlo corrections and theoretical calculations of neutron inelastic scattering cross section of 115In

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Xiao, Jun; Luo, Xiaobing

    2016-10-01

    The neutron inelastic scattering cross section of 115In has been measured by the activation technique at neutron energies of 2.95, 3.94, and 5.24 MeV with the neutron capture cross sections of 197Au as an internal standard. The effects of multiple scattering and flux attenuation were corrected using the Monte Carlo code GEANT4. Based on the experimental values, the 115In neutron inelastic scattering cross sections data were theoretically calculated between the 1 and 15 MeV with the TALYS software code, the theoretical results of this study are in reasonable agreement with the available experimental results.

  4. Elastic and inelastic light scattering of colloidal particles

    NASA Astrophysics Data System (ADS)

    Kerker, M.

    1985-06-01

    The project has been primarily concerned with both theoretical and experimental aspects of surface enhanced scattering. The theory has been extended to include concentric spherical particles, the effect of surface coverage, enhancement of coherent anti-Stokes Raman scattering and the effect of dielectric cavities. The experimental work included SERS (Surface Enhanced Raman Scattering) from citrate on silver hydrosols, surface enhanced resonance Raman scattering (SERRS) for dabsylaspartate on silver hydrosols, silver organosols and roughened silver electrodes, the effect of aggregates on SERS. In addition there have been ancillary studies dealing with absorption and luminescence by dye coated silver particles, analysis of biological cells by flow fluorimetry, and electromagnetic scattering by magnetic particles.

  5. Inelastic light scattering spectroscopy in Si/SiGe nanostructures: Strain, chemical composition and thermal properties

    NASA Astrophysics Data System (ADS)

    Tsybeskov, L.; Mala, S. A.; Wang, X.; Baribeau, J.-M.; Wu, X.; Lockwood, D. J.

    2016-11-01

    We present a review of recent studies of inelastic light scattering spectroscopy in two types of Si/SiGe nanostructures: planar superlattices and cluster (dot) multilayers including first- and second-order Raman scattering, polarized Raman scattering and low-frequency inelastic light scattering associated with folded acoustic phonons. The results are used in semi-quantitative analysis of chemical composition, strain and thermal conductivity in these technologically important materials for electronic and optoelectronic devices.

  6. Inelastic neutron scattering on the high-frequency ultrasound in single crystals

    NASA Astrophysics Data System (ADS)

    Iolin, E.; Farago, B.; Mezei, F.; Raitman, E.; Rusevich, L.

    We have observed, for the first time, inelastic neutron scattering from the phonons externally excited in single crystals. We have used ultrasonic transducers (50-200 MHz) for the excitation and neutron spin-echo spectroscopy for observing acoustic phonons. This allowed us to trace evolution of the elastic Bragg intensity I(0) and of the phonon harmonics up to the seventh order as a function of the excitation power. In contrast to the common belief, we have found that in perfect Si ultrasound does not seriously increase I(0), but an apparent increase in the Bragg intensity is entirely due to the onset of inelastic scattering. At the highest power we observed a cross-over to a chaotic phonon behavior. In deformed Si I(0) strongly decreases at a low acoustic power. The same effect could be observed in KBr and graphite crystals where the ultrasonic field made the entire mosaic blocks vibrate.

  7. Highly efficient beamline and spectrometer for inelastic soft X-ray scattering at high resolution.

    PubMed

    Lai, C H; Fung, H S; Wu, W B; Huang, H Y; Fu, H W; Lin, S W; Huang, S W; Chiu, C C; Wang, D J; Huang, L J; Tseng, T C; Chung, S C; Chen, C T; Huang, D J

    2014-03-01

    The design, construction and commissioning of a beamline and spectrometer for inelastic soft X-ray scattering at high resolution in a highly efficient system are presented. Based on the energy-compensation principle of grating dispersion, the design of the monochromator-spectrometer system greatly enhances the efficiency of measurement of inelastic soft X-rays scattering. Comprising two bendable gratings, the set-up effectively diminishes the defocus and coma aberrations. At commissioning, this system showed results of spin-flip, d-d and charge-transfer excitations of NiO. These results are consistent with published results but exhibit improved spectral resolution and increased efficiency of measurement. The best energy resolution of the set-up in terms of full width at half-maximum is 108 meV at an incident photon energy tuned about the Ni L3-edge.

  8. Bessel-Weighted Asymmetries in Semi Inclusive Deep Inelastic Scattering

    SciTech Connect

    D. Boer, L. Gamberg, B.U. Musch, A. Prokudin

    2011-10-01

    The concept of weighted asymmetries is revisited for semi-inclusive deep inelastic scattering. We consider the cross section in Fourier space, conjugate to the outgoing hadron's transverse momentum, where convolutions of transverse momentum dependent parton distribution functions and fragmentation functions become simple products. Individual asymmetric terms in the cross section can be projected out by means of a generalized set of weights involving Bessel functions. Advantages of employing these Bessel weights are that they suppress (divergent) contributions from high transverse momentum and that soft factors cancel in (Bessel-) weighted asymmetries. Also, the resulting compact expressions immediately connect to previous work on evolution equations for transverse momentum dependent parton distribution and fragmentation functions and to quantities accessible in lattice QCD. Bessel weighted asymmetries are thus model independent observables that augment the description and our understanding of correlations of spin and momentum in nucleon structure.

  9. An inelastic neutron scattering study of dietary phenolic acids.

    PubMed

    Marques, M Paula M; Batista de Carvalho, Luís A E; Valero, Rosendo; Machado, Nelson F L; Parker, Stewart F

    2014-04-28

    The conformational preferences and hydrogen-bonding motifs of several potential chemopreventive hydroxycinnamic derivatives were determined by inelastic neutron scattering spectroscopy. The aim is to understand their recognized beneficial activity and establish reliable structure-activity relationships for these types of dietary phytochemicals. A series of phenolic acids with different hydroxyl/methoxyl ring substitution patterns were studied: trans-cinnamic, p-coumaric, m-coumaric, trans-caffeic and ferulic acids. Their INS spectra were completely assigned by theoretical calculations performed at the Density Functional Theory level, for the isolated molecule, dimeric centrosymmetric species and the solid (using plane-wave expansion approaches). Access to the low energy vibrational region of the spectra enabled the identification of particular modes associated with intermolecular hydrogen-bonding interactions, which are the determinants of the main conformational preferences and antioxidant capacity of these systems.

  10. Inelastic X-ray Scattering Studies of Zeolite Collapse

    SciTech Connect

    Greaves, G. Neville; Kargl, Florian; Ward, David; Holliman, Peter; Meneau, Florian

    2009-01-29

    In situ inelastic x-ray scattering (IXS) experiments have been used to probe heterogeneity and deformability in zeolte Y as this thermally collapses to a high density amorphous (HDA) aluminosilicate phase. The Landau-Placzek ratio R{sub LP} falls slowly as amorphisation advances, increasing in the later stages of collapse clearly showing how homogeneity improves non-linearly--behaviour linked closely with the decline in molar volume V{sub Molar}. The Brillouin frequency {omega}{sub Q} also decreases with amorphisation in a similar fashion, signifying a non-uniform decrease in the speed of sound v{sub l}. All of these changes with zeolite amorphisation infer formation of an intermediate low density amorphous (LDA) phase. This low entropy or 'perfect glass' has mechanical properties which are closer to the zeolite rather to the HDA glass--notably a very small value of Poisson's Ratio signifying unusually low resistance to deformation.

  11. Resonance Region Structure Functions and Parity Violating Deep Inelastic Scattering

    SciTech Connect

    Carl E. Carlson, Benjamin C. Rislow

    2012-04-01

    The primary motive of parity violating deep inelastic scattering experiments has been to test the standard model, particularly the axial couplings to the quarks, in the scaling region. The measurements can also test for the validity of models for the off-diagonal structure functions $F_{1,2,3}^{\\gamma Z}(x,Q^2)$ in the resonance region. The off-diagonal structure functions are important for the accurate calculation of the $\\gamma Z$-box correction to the weak charge of the proton. Currently, with no data to determine $F_{1,2,3}^{\\gamma Z}(x,Q^2)$ directly, models are constructed by modifying existing fits to electromagnetic data. We present the asymmetry value for deuteron and proton target predicted by several different $F_{1,2,3}^{\\gamma Z}(x,Q^2)$ models, and demonstrate that there are notable disagreements.

  12. Dirac Calculations for Proton Inelastic Scattering at Intermediate Energies

    NASA Astrophysics Data System (ADS)

    El-Nohy, N. A.; El-Hammamy, M. N.; Aly, N. E.; Abdel-Moneim, A. M.; Hamza, A. F.

    2016-09-01

    Relativistic proton inelastic scattering from different targets (16O, 24Mg, 28Si, 40Ca, 54Fe, 58Ni, 90Zr, 154Sm, 176Yb, and 208Pb) at intermediate energies is analyzed in the framework of phenomenological optical potentials based on the Dirac formalism. Parameters of the Dirac phenomenological potential with Woods Saxon (WS) shape are obtained. The first order vibrational collective model with one phonon is used to calculate the transition optical potentials to the first low-lying excited state (2+) of the investigated target nuclei. Also, the variation of deformation length (δ) with energy and mass number is studied. It is noticed that the deformation length increases slightly with energy at intermediate range.

  13. Inelastic neutron scattering from damped collective vibrations of macromolecules

    NASA Astrophysics Data System (ADS)

    Kneller, Gerald R.

    2000-11-01

    The present article describes the theory of neutron scattering from harmonically vibrating molecules in the framework of classical Langevin and Smoluchowski dynamics. For both levels of description, the input quantities are a positive definite matrix of force constants and a positive definite friction matrix. Starting from the Fokker-Planck equation of the Ornstein-Uhlenbeck process, the intermediate scattering functions for coherent and incoherent scattering as well as related static correlation functions are derived. It is demonstrated that the Langevin description on a coarse-grained time scale is identical with the Smoluchowski description if friction dominates. Inelastic neutron spectra are discussed in terms of the coherent and incoherent dynamic structure factors and the vibrational density of states. It is shown that incorporating friction on the atomic level is not equivalent to broadening the lines of the corresponding normal mode spectrum. The theory is applicable to low frequency and large amplitude motions of macromolecules as proteins and DNA. Vibrations at higher frequencies can be treated as long as they can be described in the classical approximation.

  14. Intrinsic Gilbert Damping in Metallic Ferromagnets in Ballistic Regime and the Effect of Inelastic Electron Scattering from Magnetic Moments: A Time Dependent Keldysh Green Function Approach

    NASA Astrophysics Data System (ADS)

    Mahfouzi, Farzad; Kioussis, Nicholas

    Gilbert damping in metallic ferromagnets is mainly governed by the exchange coupling between the electrons and the magnetic degree of freedom, where the time dependent evolution of the magnetization leads to the excitation of electrons and loss of energy as a result of flow of spin and charge currents. However, it turns out that when the magnetization evolves slowly in time, in the presence of spin-orbit interaction (SOI), the resonant electronic excitations has a major contribution to the damping which leads to infinite result in ballistic regime. In this work we consider the inelastic spin-flip scattering of electrons from the magnetic moments and show that in the presence of SOI it leads to the relaxation of the excited electrons. We show that in the case of clean crystal systems such scattering leads to a linear dependence of the Gilbert on the SOI strength and in the limit of diffusive systems we get the Gilbert damping expression obtained from Kambersky's Fermi breathing approach. This research was supported by NSF-PREM Grant No. DMR-1205734

  15. Inelastic Scattering of H+CO: Influence of Renner-Teller Coupling

    NASA Astrophysics Data System (ADS)

    Ndengue, Steve Alexandre; Dawes, Richard

    2016-06-01

    Carbon monoxide is after molecular hydrogen the second most abundant molecule in the interstellar medium (ISM) and also an important molecule for processes occurring in the atmosphere, and hydrocarbon combustion. The rate coefficients of CO in collision with dominant species like H, H_2, He, etc are common keys to understand the CO emission spectrum or to model combustion chemistry processes. The inelastic scattering of H+CO has indeed been intensively studied in the past decades, using mainly the so-called WKS PES developed by Werner et al or recently a modified version by Song et al. Though the spectroscopic agreement of the WKS surface with experiment is known to be quite good, there is no experimental evidence that the dynamics of the system is correctly reproduced by the surface. We will present in this talk new results on a set of HCO surfaces of the ground and the excited Renner-Teller coupled electronic states with the principal objective of studying the influence of the Renner-Teller coupling on the inelastic scattering of H+CO. Our calculations done using the MCTDH algorithm cover the 0-2 eV energy range and allow one to interpret the effect of the Renner-Teller coupling on the rovibrational inelastic scattering. Additionally, vibrational bound and resonance state calculations on this new PES and comparisons with available experimental data will be presented.

  16. Compact turnkey focussing neutron guide system for inelastic scattering investigations

    NASA Astrophysics Data System (ADS)

    Brandl, G.; Georgii, R.; Dunsiger, S. R.; Tsurkan, V.; Loidl, A.; Adams, T.; Pfleiderer, C.; Böni, P.

    2015-12-01

    We demonstrate the performance of a compact neutron guide module which boosts the intensity in inelastic neutron scattering experiments by approximately a factor of 40. The module consists of two housings containing truly curved elliptic focussing guide elements, positioned before and after the sample. The advantage of the module lies in the ease with which it may be reproducibly mounted on a spectrometer within a few hours, on the same timescale as conventional sample environments. It is particularly well suited for samples with a volume of a few mm3, thus enabling the investigation of materials which to date would have been considered prohibitively small or samples exposed to extreme environments, where there are space constraints. We benchmark the excellent performance of the module by measurements of the structural and magnetic excitations in single crystals of model systems. In particular, we report the phonon dispersion in the simple element lead. We also determine the magnon dispersion in the spinel ZnCr2Se4 (V = 12.5 mm3), where strong magnetic diffuse scattering at low temperatures evolves into distinct helical order.

  17. Elastic and inelastic scattering of neutrons from 56Fe

    NASA Astrophysics Data System (ADS)

    Ramirez, Anthony Paul; McEllistrem, M. T.; Liu, S. H.; Mukhopadhyay, S.; Peters, E. E.; Yates, S. W.; Vanhoy, J. R.; Harrison, T. D.; Rice, B. G.; Thompson, B. K.; Hicks, S. F.; Howard, T. J.; Jackson, D. T.; Lenzen, P. D.; Nguyen, T. D.; Pecha, R. L.

    2015-10-01

    The differential cross sections for elastic and inelastic scattered neutrons from 56Fe have been measured at the University of Kentucky Accelerator Laboratory (www.pa.uky.edu/accelerator) for incident neutron energies between 2.0 and 8.0 MeV and for the angular range 30° to 150°. Time-of-flight techniques and pulse-shape discrimination were employed for enhancing the neutron energy spectra and for reducing background. An overview of the experimental procedures and data analysis for the conversion of neutron yields to differential cross sections will be presented. These include the determination of the energy-dependent detection efficiencies, the normalization of the measured differential cross sections, and the attenuation and multiple scattering corrections. Our results will also be compared to evaluated cross section databases and reaction model calculations using the TALYS code. This work is supported by grants from the U.S. Department of Energy-Nuclear Energy Universities Program: NU-12-KY-UK-0201-05, and the Donald A. Cowan Physics Institute at the University of Dallas.

  18. Self Organizing Maps for use in Deep Inelastic Scattering

    NASA Astrophysics Data System (ADS)

    Askanazi, Evan

    2015-04-01

    Self Organizing Maps are a type of artificial neural network that has been proven to be particularly useful in solving complex problems in neural biology, engineering, robotics and physics. We are attempting to use the Self Organizing Map to solve problems and probe phenomenological patterns in subatomic physics, specifically in Deep Inelastic Scattering (DIS). In DIS there is a cross section in electron hadron scattering that is dependent on the momentum fraction x of the partons in the hadron and the momentum transfer of the virtual photon exchanged. There is a soft cross part of this cross section that currently can only be found through experimentation; this soft part is comprised of Structure Functions which in turn are comprised of the Parton Distribution Functions (PDFs). We aim to use the Self Organizing Process, or SOP, to take theoretical models of these PDFs and fit it to the previous, known data. The SOP will also be used to probe the behavior of the PDFs in particular at large x values, in order to observe how they congregate. The ability of the SOPto take multidimensional data and convert it into two dimensional output is anticipated to be particularly useful in achieving this aim.

  19. Compact turnkey focussing neutron guide system for inelastic scattering investigations

    SciTech Connect

    Brandl, G.; Georgii, R.; Dunsiger, S. R.; Tsurkan, V.; Loidl, A.; Adams, T.; Pfleiderer, C.; Böni, P.

    2015-12-21

    We demonstrate the performance of a compact neutron guide module which boosts the intensity in inelastic neutron scattering experiments by approximately a factor of 40. The module consists of two housings containing truly curved elliptic focussing guide elements, positioned before and after the sample. The advantage of the module lies in the ease with which it may be reproducibly mounted on a spectrometer within a few hours, on the same timescale as conventional sample environments. It is particularly well suited for samples with a volume of a few mm{sup 3}, thus enabling the investigation of materials which to date would have been considered prohibitively small or samples exposed to extreme environments, where there are space constraints. We benchmark the excellent performance of the module by measurements of the structural and magnetic excitations in single crystals of model systems. In particular, we report the phonon dispersion in the simple element lead. We also determine the magnon dispersion in the spinel ZnCr{sub 2}Se{sub 4} (V = 12.5 mm{sup 3}), where strong magnetic diffuse scattering at low temperatures evolves into distinct helical order.

  20. Opportunities in Inelastic Neutron Scattering at Oak Ridge National Laboratory

    NASA Astrophysics Data System (ADS)

    Granroth, Garrett E.

    2007-11-01

    The Spallation Neutron Source (SNS) and the High Flux Isotope Reactor (HFIR) are the two world class neutron scattering user facilities located at Oak Ridge National Laboratory. Inelastic scattering instruments designed to optimally utilize their source are either in, or will soon enter, the user program. The HFIR has three thermal and plans for two cold, neutron triple axis spectrometers in the user program. These instruments examine localized regions of Q and φ space with tunable resolution. The spectrometers at the SNS cover broad ranges of Q and φ space. The BASIS instrument, in the user program, uses near backscattering analyzer crystals to provide 3μeV φ resolution. The ARCS thermal to epithermal neutron spectrometer is in commissioning and the Cold Neutron Chopper Spectrometer will enter commissioning soon. These instruments provide moderate, tunable resolution, and detector coverage out to 140^o. The SEQUOIA spectrometer, complete in 2008, is the fine resolution complement of ARCS. The finest resolution is provided by the Spin-Echo spectrometer; complete in 2009. The HYSPEC spectrometer, available in 2011, will provide polarized capabilities and optimized flux for neutrons of thermal energies. Finally, the Vision chemical spectrometer will use crystal analyzers to access φ in the epithermal range. These instruments, along with representative science to be performed on each, will be presented.

  1. Molecular-dynamics study of ionic motions and neutron inelastic scattering in α-AgI

    NASA Astrophysics Data System (ADS)

    Chiarotti, Guido L.; Jacucci, G.; Rahman, A.

    1986-11-01

    Contrary to the current interpretation of inelastic-neutron-scattering data on α-AgI, molecular-dynamics calculations show that inelastic neutron scattering is dominated by coherent scattering from Ag+ ions. The calculations agree with the available data. Ag+ ions diffuse by jumps between tetrahedral sites, the consequences being in complete accord with the Chudley-Elliot model only if the full geometrical complexity of these sites is included. Phonon modes due to I- motions are predicted for certain wave vectors.

  2. Nonlinear inelastic electron scattering revealed by plasmon-enhanced electron energy-loss spectroscopy

    NASA Astrophysics Data System (ADS)

    Xu, Chun Kai; Liu, Wen Jie; Zhang, Pan Ke; Li, Meng; Zhang, Han Jun; Xu, Ke Zun; Luo, Yi; Chen, Xiang Jun

    2014-10-01

    Electron energy-loss spectroscopy is a powerful tool for identifying the chemical composition of materials. It relies mostly on the measurement of inelastic electrons, which carry specific atomic or molecular information. Inelastic electron scattering, however, has a very low intensity, often orders of magnitude weaker than that of elastically scattered electrons. Here, we report the observation of enhanced inelastic electron scattering from silver nanostructures, the intensity of which can reach up to 60% of its elastic counterpart. A home-made scanning probe electron energy-loss spectrometer was used to produce highly localized plasmonic excitations, significantly enhancing the strength of the local electric field of silver nanostructures. The intensity of inelastic electron scattering was found to increase nonlinearly with respect to the electric field generated by the tip-sample bias, providing direct evidence of nonlinear electron scattering processes.

  3. Measurement of parity-violating asymmetry in electron-deuteron inelastic scattering

    DOE PAGESBeta

    Wang, D.; Pan, K.; Subedi, R.; Ahmed, Z.; Allada, K.; Aniol, K. A.; Armstrong, D. S.; Arrington, J.; Bellini, V.; Beminiwattha, R.; et al

    2015-04-01

    The parity-violating asymmetries between a longitudinally-polarized electron beam and an unpolarized deuterium target have been measured recently. The measurement covered two kinematic points in the deep inelastic scattering region and five in the nucleon resonance region. We provide here details of the experimental setup, data analysis, and results on all asymmetry measurements including parity-violating electron asymmetries and those of inclusive pion production and beam-normal asymmetries. The parity-violating deep-inelastic asymmetries were used to extract the electron-quark weak effective couplings, and the resonance asymmetries provided the first evidence for quark-hadron duality in electroweak observables. These electron asymmetries and their interpretation were publishedmore » earlier, but are presented here in more detail.« less

  4. Measurement of parity-violating asymmetry in electron-deuteron inelastic scattering

    SciTech Connect

    Wang, D.; Pan, K.; Subedi, R.; Ahmed, Z.; Allada, K.; Aniol, K. A.; Armstrong, D. S.; Arrington, J.; Bellini, V.; Beminiwattha, R.; Benesch, J.; Benmokhtar, F.; Bertozzi, W.; Camsonne, A.; Canan, M.; Cates, G. D.; Chen, J.-P.; Chudakov, E.; Cisbani, E.; Dalton, M. M.; de Jager, C. W.; De Leo, R.; Deconinck, W.; Deng, X.; Deur, A.; Dutta, C.; Fassi, L. El; Erler, J.; Flay, D.; Franklin, G. B.; Friend, M.; Frullani, S.; Garibaldi, F.; Gilad, S.; Giusa, A.; Glamazdin, A.; Golge, S.; Grimm, K.; Hafidi, K.; Hansen, J.-O.; Higinbotham, D. W.; Holmes, R.; Holmstrom, T.; Holt, R. J.; Huang, J.; Hyde, C. E.; Jen, C. M.; Jones, D.; Kang, Hoyoung; King, P. M.; Kowalski, S.; Kumar, K. S.; Lee, J. H.; LeRose, J. J.; Liyanage, N.; Long, E.; McNulty, D.; Margaziotis, D. J.; Meddi, F.; Meekins, D. G.; Mercado, L.; Meziani, Z.-E.; Michaels, R.; Mihovilovic, M.; Muangma, N.; Mesick, K. E.; Nanda, S.; Narayan, A.; Nelyubin, V.; Nuruzzaman, none; Oh, Y.; Parno, D.; Paschke, K. D.; Phillips, S. K.; Qian, X.; Qiang, Y.; Quinn, B.; Rakhman, A.; Reimer, P. E.; Rider, K.; Riordan, S.; Roche, J.; Rubin, J.; Russo, G.; Saenboonruang, K.; Saha, A.; Sawatzky, B.; Shahinyan, A.; Silwal, R.; Sirca, S.; Souder, P. A.; Suleiman, R.; Sulkosky, V.; Sutera, C. M.; Tobias, W. A.; Urciuoli, G. M.; Waidyawansa, B.; Wojtsekhowski, B.; Ye, L.; Zhao, B.; Zheng, X.

    2015-04-01

    The parity-violating asymmetries between a longitudinally-polarized electron beam and an unpolarized deuterium target have been measured recently. The measurement covered two kinematic points in the deep inelastic scattering region and five in the nucleon resonance region. We provide here details of the experimental setup, data analysis, and results on all asymmetry measurements including parity-violating electron asymmetries and those of inclusive pion production and beam-normal asymmetries. The parity-violating deep-inelastic asymmetries were used to extract the electron-quark weak effective couplings, and the resonance asymmetries provided the first evidence for quark-hadron duality in electroweak observables. These electron asymmetries and their interpretation were published earlier, but are presented here in more detail.

  5. Phonon dynamics and inelastic neutron scattering of sodium niobate

    NASA Astrophysics Data System (ADS)

    Mishra, S. K.; Gupta, M. K.; Mittal, R.; Zbiri, M.; Rols, S.; Schober, H.; Chaplot, S. L.

    2014-05-01

    Sodium niobate (NaNbO3) exhibits an extremely complex sequence of structural phase transitions in the perovskite family and therefore provides an excellent model system for understanding the mechanism of structural phase transitions. We report temperature dependence of inelastic neutron scattering measurements of phonon densities of states in sodium niobate. The measurements are carried out in various crystallographic phases of this material at various temperatures from 300 to 1048 K. The phonon spectra exhibit peaks centered on 19, 37, 51, 70, and 105 meV. Interestingly, the peak near 70 meV shifts significantly towards lower energy with increasing temperature, while the other peaks do not exhibit any appreciable shift. The phonon spectra at 783 K show prominent change and become more diffusive as compared to those at 303 K. In order to better analyze these features, we have performed first-principles lattice dynamics calculations based on the density functional theory. The computed phonon density of states is found to be in good agreement with the experimental data. Based on our calculation we are able to assign the characteristic Raman modes in the antiferroelectric phase, which are due to the folding of the T (ω = 95 cm-1) and Δ (ω = 129 cm-1) points of the cubic Brillouin zone, to the A1g symmetry.

  6. Amorphous polymorphis in ice investigated by inelastic neutron scattering

    NASA Astrophysics Data System (ADS)

    Schober, H.; Koza, M.; Tölle, A.; Fujara, F.; Angell, C. A.; Böhmer, R.

    High-density I lda and low-density I lda amorphous have been investigated by inelastic neutron scattering (INS) with emphasis on the energy window from 0.5 to 20 meV. At variance with earlier measurements the spectra in the I lda phase show a simple ω2 behaviour in the acoustic region and the temperature dependence is found to be harmonic. I lda converts with a strongly temperature-dependent rate towards I lda ice. We have investigated in detail the time evolution of both the static and dynamic response functions at several temperatures. Elastic small-angle signals indicate the presence of strong heterogeneties at the early stages of the conversion process. At least two different time scales are present in the transition. The structural changes are reflected in the frequency distribution. The first peak in the phonon density-of-states softens appreciably when going from I lda to I lda. In the acoustic region there is evidence that I lda is softer than both I lda and crystalline cubic ice I c. No signs of a fast ps process related to melting can be detected in the dynamics.

  7. Semi-Inclusive Pion Electroproduction in Deep Inelastic Scattering

    NASA Astrophysics Data System (ADS)

    Gohn, Wesley; Avakian, Harut; Joo, Kyungseon; Ungaro, Maurizio

    2010-02-01

    Measurements of pion electro-production in semi-inclusive deep inelastic scattering (SIDIS) have been performed. Data were taken with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab using a 5.498 GeV longitudinally polarized electron beam and an unpolarized liquid hydrogen target during the E1-f run period in 2003. All three pion channels (&+circ;, 0̂ and &-circ;) were measured simultaneously over a large range of kinematics(Q^2 1-4 GeV^2 and x 0.1-0.5). Preliminary results from our study of single-spin azimuthal asymmetries from all three pion channels as functions of x, z, and PT, from which ALU^sinφ is extracted, will be presented, as will preliminary measurements of AUU^cosφ and AUU^cos2φ in the charged pion channels. This new high statistical data could provide access to transverse-momentum dependent parton distribution functions (TMD's), which are thought to be important in understanding of the physics underlying the spin structure of the nucleon. )

  8. Inelastic-impurity-scattering-induced spin texture and topological transitions in surface electron waves

    NASA Astrophysics Data System (ADS)

    Fransson, J.

    2015-09-01

    Inelastic scattering off magnetic impurities in a spin-chiral two-dimensional electron gas, e.g., the Rashba system, is shown to generate topological changes in the spin texture of the electron waves emanating from the scattering center. While elastic scattering gives rise to a purely in-plane spin texture for an in-plane magnetic scattering potential, out-of-plane components emerge upon activation of inelastic scattering processes. This property leads to a possibility to make controlled transitions between trivial and nontrivial topologies of the spin texture.

  9. Inelastic neutron scattering from single crystal Zn under high pressure

    NASA Astrophysics Data System (ADS)

    Morgan, J. G.; von Dreele, R. B.; Wochner, P.; Shapiro, S. M.

    1996-07-01

    Inelastic neutron-scattering experiments have been performed for single crystals of Zn under pressures up to 8.8 GPa at 300 K. The phonon modes q/qmax=ξ=0.075 and ξ=0.10 were measured in the transverse acoustic branch Σ3, where q=0 corresponds with the elastic constant C44. The phonon energy showed a substantial hardening with increasing pressure. The experimental data below 6.8 GPa for ξ=0.075 yield a constant Grüneisen mode γi=-lnωi/lnV of 2.25 in good agreement with a previous calculation [H. Ledbetter, Phys. Status Solidi B 181, 81 (1994)]. Above 6.8 GPa, there is a very rapid increase of γi which is indicative of the presence of a giant Kohn anomaly. This rapid divergence at high pressure indicates that a phonon softening may occur at pressures higher than 8.8 GPa caused by the collapse of the giant Kohn anomaly via an electronic topological transition (ETT). In an earlier Mössbauer Zn study at 4 K [W. Potzel et al., Phys. Rev. Lett. 74, 1139 (1994)], a drastic drop of the Lamb-Mössbauer factor was observed at 6.6 GPa, which was interpreted as being due to phonon softening, indicating this ETT had occurred. This paper also compares the compressibility data for single crystal Zn and Zn powder using neutron scattering. The results were found to be similar to an earlier x-ray Zn powder experiment [O. Schulte et al., High Pressure Res. 6, 169 (1991)].

  10. Multiparticle production in deep inelastic lepton scattering and soft proton proton collisions

    SciTech Connect

    Werner, K.

    1987-06-01

    We demonstrate how the theoretical knowledge about multiparticle production in deep inelastic lepton scattering can be incorporated into a multistring model for low p/sub t/ proton proton collisions. 25 refs., 8 figs.

  11. Fine structure of inelastic electron scattering cross-section spectra for MN

    NASA Astrophysics Data System (ADS)

    Parshin, A. S.; Igumenov, A. Yu; Mikhlin, Yu L.; Pchelyakov, O. P.; Zhigalov, V. S.

    2016-04-01

    The comparative analysis of the reflection electron energy loss spectra and the inelastic electron scattering cross-section spectra for Mn was carried out. It is shown that inelastic electron scattering cross-section spectra have certain advantages in the study of the interaction of electrons with the substance as compared to the electron energy loss spectra. The inelastic electron scattering cross section spectra fine structure was analysed by fitting the experimental spectra using the 3 parameters Lorentzian-type formula of Tougaard. This method was used for the quantitative analysis of the contributions of various loss processes in the inelastic electron scattering cross section spectra, determination of the loss peaks energies and origin.

  12. Calibration and absolute normalization procedure of a new Deep Inelastic Neutron Scattering spectrometer

    NASA Astrophysics Data System (ADS)

    Rodríguez Palomino, L. A.; Blostein, J. J.; Dawidowski, J.

    2011-08-01

    We describe the calibration process of a new Deep Inelastic Neutron Scattering (DINS) spectrometer, recently implemented at the Bariloche Electron LINAC (Argentina), consisting in the determination of the incident neutron spectrum, dead-time and electronic delay of the data acquisition line, and detector bank efficiency. For this purpose, samples of lead, polyethylene and graphite of different sizes were employed. Their measured spectra were corrected by multiple scattering, attenuation and detector efficiency effects, by means of an ad hoc Monte Carlo code. We show that the corrected spectra are correctly scaled with respect to the scattering power of the tested materials within a 2% of experimental error, thus allowing us to define an experimental constant that links the arbitrary experimental scale (number of recorded counts per monitor counts) with the involved cross-sections. The present work also serves to analyze the existence of possible sources of systematic errors.

  13. Possibility of detecting triple gluon coupling and Adler-Bell-Jackiw anomaly in polarized deep inelastic scattering

    SciTech Connect

    Lam, C.S.; Li, B.A.

    1980-05-01

    A way to detect experimentally the existence of triple gluon coupling and the Adler-Bell-Jackiw anomaly is to measure the Q/sup 2/-dependence of polarized deep inelastic scattering. These effects lead to a ln ln Q/sup 2/ term which we calculate by introducing a new gluon operator in the Wilson expansion.

  14. Reactive and Inelastic Scattering Dynamics of Hyperthermal Oxygen Atoms on a Liquid Hydrocarbon Surface

    NASA Astrophysics Data System (ADS)

    Minton, Timothy K.

    2004-03-01

    The saturated hydrocarbon liquid, squalane (2,6,10,15,19,23-hexamethyltetracosane), was used as a target surface for model studies of hyperthermal O-atom reactions with a hydrocarbon surface. Beams containing hyperthermal O(^3P) atoms at average translational energies of 3.0 or 5.2 eV were directed at a continuously refreshed squalane surface, and products that scattered from the surface were monitored with a rotatable mass spectrometer detector. Inelastically scattered O and reactively scattered OH and H_2O have been detected, and the dynamical behavior of these products has been characterized. Both the reactive and nonreactive channels were found to occur through thermal and nonthermal processes, with the nonthermal processes dominating. The initial step leading to formation of OH and H_2O products is believed to be H-atom abstraction to form OH. The direct inelastic scattering of O and the direct H-atom abstraction to form OH occur through gas-phase-like collisions, which may be described by a kinematic picture similar to that used to describe scattering in crossed-beams experiments. This kinematic picture allows the determination of the effective surface mass encountered by the incident O atom, the atom-surface collision energy in the center-of-mass (c.m.) frame, and the fraction of the c.m. collision energy that goes into translation of the scattered gaseous product and the recoiling surface fragment. Center-of-mass velocity-flux maps for scattered OH indicate either single-collision events through a largely collinear O-H-C transition state or multiple-collision events in which OH, likely formed by a stripping mechanism, scatters inelastically from the surface. Further studies are underway to investigate experimentally the dynamics of a possible carbon-containing product (OCH_3) that is predicted by theory to be formed (in addition to OH and H_2O) in the hyperthermal reaction of O(^3P) with a hydrocarbon surface.

  15. Nuclear dependence of structure functions in the shadowing region of deep inelastic scattering

    SciTech Connect

    Berger, E.L.; Qiu, Jianwei

    1988-07-27

    A discussion of nuclear shadowing in deep inelastic lepton scattering is presented. We show that the parton recombination model suggests that shadowing should begin to occur at larger values of Bjorken x as A increases. This expectation as well as that of weak dependence on Q/sup 2/, and the trend of the x dependence of the shadowing phenomenon are consistent with recent data. Shadowing at small x is combined with nuclear bound state effects, responsible for nuclear dependence at larger x, to provide description of the A dependence of the structure function for the entire range of x. 21 refs., 5 figs.

  16. Spherical momentum distribution of the protons in hexagonal ice from modeling of inelastic neutron scattering data

    NASA Astrophysics Data System (ADS)

    Flammini, D.; Pietropaolo, A.; Senesi, R.; Andreani, C.; McBride, F.; Hodgson, A.; Adams, M. A.; Lin, L.; Car, R.

    2012-01-01

    The spherical momentum distribution of the protons in ice is extracted from a high resolution deep inelastic neutron scattering experiment. Following a recent path integral Car-Parrinello molecular dynamics study, data were successfully interpreted in terms of an anisotropic Gaussian model, with a statistical accuracy comparable to that of the model independent scheme used previously, but providing more detailed information on the three dimensional potential energy surface experienced by the proton. A recently proposed theoretical concept is also employed to directly calculate the mean force from the experimental neutron Compton profile, and to evaluate the accuracy required to unambiguously resolve and extract the effective proton potential from the experimental data.

  17. Spherical momentum distribution of the protons in hexagonal ice from modeling of inelastic neutron scattering data.

    PubMed

    Flammini, D; Pietropaolo, A; Senesi, R; Andreani, C; McBride, F; Hodgson, A; Adams, M A; Lin, L; Car, R

    2012-01-14

    The spherical momentum distribution of the protons in ice is extracted from a high resolution deep inelastic neutron scattering experiment. Following a recent path integral Car-Parrinello molecular dynamics study, data were successfully interpreted in terms of an anisotropic Gaussian model, with a statistical accuracy comparable to that of the model independent scheme used previously, but providing more detailed information on the three dimensional potential energy surface experienced by the proton. A recently proposed theoretical concept is also employed to directly calculate the mean force from the experimental neutron Compton profile, and to evaluate the accuracy required to unambiguously resolve and extract the effective proton potential from the experimental data. PMID:22260600

  18. Resonant inelastic x-ray scattering at the limit of subfemtosecond natural lifetime

    SciTech Connect

    Marchenko, T.; Journel, L.; Marin, T.; Guillemin, R.; Carniato, S.; Simon, M.; Zitnik, M.; Kavcic, M.; Bucar, K.; Mihelic, A.; Hoszowska, J.; Cao, W.

    2011-04-14

    We present measurements of the resonant inelastic x-ray scattering (RIXS) spectra of the CH{sub 3}I molecule in the hard-x-ray region near the iodine L{sub 2} and L{sub 3} absorption edges. We show that dispersive RIXS spectral features that were recognized as a fingerprint of dissociative molecular states can be interpreted in terms of ultrashort natural lifetime of {approx}200 attoseconds in the case of the iodine L-shell core-hole. Our results demonstrate the capacity of the RIXS technique to reveal subtle dynamical effects in molecules with sensitivity to nuclear rearrangement on a subfemtosecond time scale.

  19. Parity-violating deep-inelastic electron-deuteron scattering: Higher twist and parton angular momentum

    NASA Astrophysics Data System (ADS)

    Seng, Chien-Yeah; Ramsey-Musolf, Michael J.

    2013-07-01

    We study the effect of parton angular momentum on the twist-four correction to the left-right asymmetry in the electron-deuteron parity-violating deep-inelastic scattering (PVDIS). We show that this higher-twist correction is transparent to the dynamics of parton angular momentum needed to account for the Sivers and Boer-Mulders functions and spin-independent parton distribution functions. A sufficiently precise measurement of the PVDIS asymmetry may, thus, provide additional information about the parton dynamics responsible for nucleon spin.

  20. Inelastic scattering in condensed matter with high intensity Moessbauer radiation

    NASA Astrophysics Data System (ADS)

    Yelon, W. B.; Schupp, G.

    1991-05-01

    We give a progress report for the work which has been carried out in the last three years with DOE support. A facility for high-intensity Moessbauer scattering is not fully operational at the University of Missouri Research Reactor (MURR) as well as a facility at Purdue, using special isotopes produced at MURR. High precision, fundamental Moessbauer effect studies have been carried out using Bragg scattering filters to suppress unwanted radiation. These have led to a Fourier transform method for describing Moessbauer effect (ME) lineshape and a direct method of fitting ME data to the convolution integral. These methods allow complete correction for source resonance self absorption and the accurate representation of interference effects that add an asymmetric component to the ME lines. We have begun applying these techniques to attenuated ME sources whose central peak has been attenuated by stationary resonant absorbers, to make a novel independent determination of interference parameters and line-shape behavior in the resonance asymptotic region. This analysis is important to both fundamental ME studies and to scattering studies for which a deconvolution is essential for extracting the correct recoilless fractions and interference parameters. A number of scattering studies have been successfully carried out including a study of the thermal diffuse scattering in Si, which led to an analysis of the resolution function for gamma-ray scattering. Also studied was the anharmonic motion in Na metal and the charge density wave satellite reflection Debye-Waller factor in TaS2, which indicate phason rather than phonon behavior. Using a specially constructed sample cell which enables us to vary temperatures from -10 C to 110 C, we have begun quasielastic diffusion studies in viscous liquids and current results are summarized. Included are the temperature and Q dependence of the scattering in pentadecane and diffusion in glycerol.

  1. Elastic and inelastic neutron scattering from /sup 27/Al at 11, 14, and 17 MeV

    SciTech Connect

    Whisnant, C.S.; Dave, J.H.; Gould, C.R.

    1984-11-01

    Fast neutron scattering cross sections have been measured for /sup 27/Al using a neutron time-of-flight facility. Angular distributions were measured at angles from 20/sup 0/ to 160/sup 0/ in 5/sup 0/ increments, at incident neutron energies of 11, 14, and 17 MeV. Data are presented for elastic scattering and for inelastic scattering to the sum of the 0.84 and 1.01 MeV states, the 2.21 MeV state, and the sum of the 2.73, 2.98, and 3.00 MeV states. After correcting for compound nucleus effects, the elastic scattering cross sections are well reproduced by the spherical optical model using a linear energy dependence in the real well depth. The inelastic data are interpreted with a coupled channels calculation and the excited core model.

  2. Analytic expressions for the inelastic scattering and energy loss of electron and proton beams in carbon nanotubes

    SciTech Connect

    Emfietzoglou, D.; Kyriakou, I.; Garcia-Molina, R.; Abril, I.; Kostarelos, K.

    2010-09-15

    We have determined ''effective'' Bethe coefficients and the mean excitation energy of stopping theory (I-value) for multiwalled carbon nanotubes (MWCNTs) and single-walled carbon nanotube (SWCNT) bundles based on a sum-rule constrained optical-data model energy loss function with improved asymptotic properties. Noticeable differences between MWCNTs, SWCNT bundles, and the three allotropes of carbon (diamond, graphite, glassy carbon) are found. By means of Bethe's asymptotic approximation, the inelastic scattering cross section, the electronic stopping power, and the average energy transfer to target electrons in a single inelastic collision, are calculated analytically for a broad range of electron and proton beam energies using realistic excitation parameters.

  3. Born Hartree Bethe approximation in the theory of inelastic electron molecule scattering

    NASA Astrophysics Data System (ADS)

    Kretinin, I. Yu; Krisilov, A. V.; Zon, B. A.

    2008-11-01

    We propose a new approximation in the theory of inelastic electron atom and electron molecule scattering. Taking into account the completeness property of atomic and molecular wavefunctions, considered in the Hartree approximation, and using Bethe's parametrization for electronic excitations during inelastic collisions via the mean excitation energy, we show that the calculation of the inelastic total integral cross-sections (TICS), in the framework of the first Born approximation, involves only the ground-state wavefunction. The final analytical formula obtained for the TICS, i.e. for the sum of elastic and inelastic ones, contains no adjusting parameters. Calculated TICS for electron scattering by light atoms and molecules (He, Ne, and H2) are in good agreement within the experimental data; results show asymptotic coincidence for heavier ones (Ar, Kr, Xe and N2).

  4. Inelastic X-ray scattering from 6H-SiC

    SciTech Connect

    Macrander, A.T.; Blasdell, B.; Montano, P.A. |; Kao, C.C.

    1995-07-01

    The authors have studied electronic excitations in 6H-SiC using inelastic x-ray scattering. Inelastic scattering spectra were measured at momentum transfers ranging from 0.47 {angstrom}{sup {minus}1} to 2.00 {angstrom}{sup {minus}1} along the c-axis in the hexagonal lattice, i.e. , along [00{center_dot}1], and from 0.67 {angstrom}{sup {minus}1} to 2.00 {angstrom}{sup {minus}1} along the a-axis, i.e., alone, [10{center_dot}0]. Comparison of the two sets of data reveals an orientation dependence of the spectra, except for a characteristic peak at 22--23 eV that occurs for both directions at low Q. This peak has also been observed in electron energy loss spectroscopy studies and is identified as a bulk plasmon. The orientation dependence of the other spectral features is indicative of band structure effects. These data were obtained using a Ge(444) analyzer in a near backscattering geometry.

  5. Parity Violation Inelastic Scattering Experiments at 6 GeV and 12 GeV Jefferson Lab

    SciTech Connect

    Sulkosky, Vincent A.; et. al.,

    2015-03-01

    We report on the measurement of parity-violating asymmetries in the deep inelastic scattering and nucleon resonance regions using inclusive scattering of longitudinally polarized electrons from an unpolarized deuterium target. The effective weak couplings C$_{2q}$ are accessible through the deep-inelastic scattering measurements. Here we report a measurement of the parity-violating asymmetry, which yields a determination of 2C$_{2u}$ - C$_{2d}$ with an improved precision of a factor of five relative to the previous result. This result indicates evidence with 95% confidence that the 2C$_{2u}$ - C$_{2d}$ is non-zero. This experiment also provides the first parity-violation data covering the whole resonance region, which provide constraints on nucleon resonance models. Finally, the program to extend these measurements at Jefferson Lab in the 12 GeV era using the Solenoidal Large Intensity Device was also discussed.

  6. Dynamics of electron-phonon scattering: crystal- and angular-momentum transfer probed by resonant inelastic x-ray scattering.

    PubMed

    Beye, M; Hennies, F; Deppe, M; Suljoti, E; Nagasono, M; Wurth, W; Föhlisch, A

    2009-12-01

    Experimentally, we observe angular-momentum transfer in electron-phonon scattering, although it is commonly agreed that phonons transfer mostly linear momentum. Therefore, the incorporation of angular momentum to describe phonons is necessary already for simple semiconductors and bears significant implications for the formation of new quasiparticles in correlated functional materials. Separation of linear and angular-momentum transfer in electron-phonon scattering is achieved by highly selective excitations on the femtosecond time scale of resonant inelastic x-ray scattering.

  7. Comparative analysis of characteristic electron energy loss spectra and inelastic scattering cross-section spectra of Fe

    NASA Astrophysics Data System (ADS)

    Parshin, A. S.; Igumenov, A. Yu.; Mikhlin, Yu. L.; Pchelyakov, O. P.; Zhigalov, V. S.

    2016-05-01

    The inelastic electron scattering cross section spectra of Fe have been calculated based on experimental spectra of characteristic reflection electron energy loss as dependences of the product of the inelastic mean free path by the differential inelastic electron scattering cross section on the electron energy loss. It has been shown that the inelastic electron scattering cross-section spectra have certain advantages over the electron energy loss spectra in the analysis of the interaction of electrons with substance. The peaks of energy loss in the spectra of characteristic electron energy loss and inelastic electron scattering cross sections have been determined from the integral and differential spectra. It has been shown that the energy of the bulk plasmon is practically independent of the energy of primary electrons in the characteristic electron energy loss spectra and monotonically increases with increasing energy of primary electrons in the inelastic electron scattering cross-section spectra. The variation in the maximum energy of the inelastic electron scattering cross-section spectra is caused by the redistribution of intensities over the peaks of losses due to various excitations. The inelastic electron scattering cross-section spectra have been analyzed using the decomposition of the spectra into peaks of the energy loss. This method has been used for the quantitative estimation of the contributions from different energy loss processes to the inelastic electron scattering cross-section spectra of Fe and for the determination of the nature of the energy loss peaks.

  8. Miscibility gap and phonon thermodynamics of Fe-Au alloys studied by inelastic neutron scattering and nuclear-resonant inelastic x-ray scattering

    SciTech Connect

    Muñoz, Jorge A.; Fultz, Brent

    2015-07-23

    Recent measurements of the phonon spectra of several Au-rich alloys of face-centered-cubic Fe-Au using inelastic neutron scattering and nuclear-resonant inelastic x-ray scattering are summarized. The Wills-Harrison model, accounting for charge transfer upon alloying, is used to explain the observed negative excess vibrational entropy of mixing, which increases the miscibility gap temperature in the system by an estimated maximum of 550 K and we adjudicate to a charge transfer from the Fe to the Au atoms that results in an increase in the electron density in the free-electron-like states and in stronger sd-hybridization. When Au is the solvent, this softens the Fe–Fe bonds but stiffens the Au–Au and Au–Fe bonds which results in a net stiffening relative to the elemental components.

  9. Miscibility gap and phonon thermodynamics of Fe-Au alloys studied by inelastic neutron scattering and nuclear-resonant inelastic x-ray scattering

    NASA Astrophysics Data System (ADS)

    Muñoz, Jorge A.; Fultz, Brent

    2015-07-01

    Recent measurements of the phonon spectra of several Au-rich alloys of face-centered-cubic Fe-Au using inelastic neutron scattering and nuclear-resonant inelastic x-ray scattering are summarized. The Wills-Harrison model, accounting for charge transfer upon alloying, is used to explain the observed negative excess vibrational entropy of mixing, which increases the miscibility gap temperature in the system by an estimated maximum of 550 K and we adjudicate to a charge transfer from the Fe to the Au atoms that results in an increase in the electron density in the free-electron-like states and in stronger sd-hybridization. When Au is the solvent, this softens the Fe-Fe bonds but stiffens the Au-Au and Au-Fe bonds which results in a net stiffening relative to the elemental components.

  10. A maximally informative version of inelastic scattering of electromagnetic waves by Langmuir waves

    SciTech Connect

    Erofeev, V. I.

    2015-09-15

    The concept of informativeness of nonlinear plasma physics scenarios is explained. Natural ideas of developing highly informative models of plasma kinetics are spelled out. A maximally informative version of inelastic scattering of electromagnetic waves by Langmuir waves in a weakly turbulent inhomogeneous plasma is developed with consideration of possible changes in wave polarization. In addition, a new formula for wave drift in spatial positions and wave vectors is derived. New scenarios of the respective wave drift and inelastic scattering are compared with the previous visions. The results indicate the need for further revision of the traditional understanding of nonlinear plasma phenomena.

  11. Enhanced Thermoelectric Power in Graphene: Violation of the Mott Relation by Inelastic Scattering.

    PubMed

    Ghahari, Fereshte; Xie, Hong-Yi; Taniguchi, Takashi; Watanabe, Kenji; Foster, Matthew S; Kim, Philip

    2016-04-01

    We report the enhancement of the thermoelectric power (TEP) in graphene with extremely low disorder. At high temperature we observe that the TEP is substantially larger than the prediction of the Mott relation, approaching to the hydrodynamic limit due to strong inelastic scattering among the charge carriers. However, closer to room temperature the inelastic carrier-optical-phonon scattering becomes more significant and limits the TEP below the hydrodynamic prediction. We support our observation by employing a Boltzmann theory incorporating disorder, electron interactions, and optical phonons. PMID:27081996

  12. Enhanced Thermoelectric Power in Graphene: Violation of the Mott Relation by Inelastic Scattering

    NASA Astrophysics Data System (ADS)

    Ghahari, Fereshte; Xie, Hong-Yi; Taniguchi, Takashi; Watanabe, Kenji; Foster, Matthew S.; Kim, Philip

    2016-04-01

    We report the enhancement of the thermoelectric power (TEP) in graphene with extremely low disorder. At high temperature we observe that the TEP is substantially larger than the prediction of the Mott relation, approaching to the hydrodynamic limit due to strong inelastic scattering among the charge carriers. However, closer to room temperature the inelastic carrier-optical-phonon scattering becomes more significant and limits the TEP below the hydrodynamic prediction. We support our observation by employing a Boltzmann theory incorporating disorder, electron interactions, and optical phonons.

  13. New inelastic process of phonon scattering by rotons

    SciTech Connect

    Pogorelov, L.A.; Sobolev, V.I.

    1983-11-01

    A new inelastic process has been discovered that determines the kinetics of superfluid helium at elevated pressures. The process involves absorption (emission) of phonons by rotons owing to the dispersion of the roton energy. Rotons moving at maximum velocity are shown to play an essential role in this process. The form of the roton dispersion relation proposed permits a good description of the kinetic processes and the results of direct measurements of the energy spectrum.

  14. An alternative scheme of angular-dispersion analyzers for high-resolution medium-energy inelastic X-ray scattering.

    PubMed

    Huang, Xian Rong

    2011-11-01

    The development of medium-energy inelastic X-ray scattering optics with meV and sub-meV resolution has attracted considerable efforts in recent years. Meanwhile, there are also concerns or debates about the fundamental and feasibility of the involved schemes. Here the central optical component, the back-reflection angular-dispersion monochromator or analyzer, is analyzed. The results show that the multiple-beam diffraction effect together with transmission-induced absorption can noticeably reduce the diffraction efficiency, although it may not be a fatal threat. In order to improve the efficiency, a simple four-bounce analyzer is proposed that completely avoids these two adverse effects. The new scheme is illustrated to be a feasible alternative approach for developing meV- to sub-meV-resolution inelastic X-ray scattering spectroscopy.

  15. State-to-state inelastic and reactive molecular beam scattering from surfaces

    SciTech Connect

    Lykke, K.R. ); Kay, B.D. )

    1990-01-01

    Resonantly enhanced multiphoton ionization (REMPI) laser spectroscopic and molecular beam-surface scattering techniques are coupled to study inelastic and reactive gas-surface scattering with state-to-state specificity. Rotational, vibrational, translational and angular distributions have been measured for the inelastic scattering of HCI and N {sub 2} from Au(111). In both cases the scattering is direct-inelastic in nature and exhibits interesting dynamical features such as rotational rainbow scattering. In an effort to elucidate the dynamics of chemical reactions occurring on surfaces we have extended our quantum-resolved scattering studies to include the reactive scattering of a beam of gas phase H-atoms from a chlorinated metal surface M-CI. The nascent rotational and vibrational distributions of the HCI product are determined using REMPI. The thermochemistry for this reaction on Au indicates that the product formation proceeding through chemisorbed H-atoms is slightly endothermic while direct reaction of a has phase H-atom with M-CI is highly exothermic (ca. 50 kcal/mole). Details of the experimental techniques, results and implications regarding the scattering dynamics are discussed. 55 ref., 8 fig.

  16. Parity Violation in Deep Inelastic Scattering at JLab 6 GeV

    SciTech Connect

    Xiaochao Zheng

    2006-05-16

    The parity-violating asymmetry in e-$^2$H deep inelastic scattering (DIS) can be used to extract the weak neutral-current coupling constants $C_{2q}$. A measurement of this asymmetry at two $Q^2$ values is planned at Jefferson Lab. Results from this experiment will provide a value of $2C_{2u}-C_{2d}$ to a precision of $\\pm 0.03$, a factor of eight improvement over our current knowledge. If all hadronic effects can be understood, this results will provide information on possible extensions of the Standard Model, complementary to other experiments dedicated to new physics searches. Presented here are the physics motivation, experimental setup, potential hadronic effects and their implications, and the future of PV DIS at Jefferson Lab.

  17. Parity violation in deep inelastic scattering at JLab 6 GeV.

    SciTech Connect

    Zheng, X.; Arrington, J.; Geesaman, D. F.; Hafidi, K.; Holt, R. J.; Jackson, H. E.; Potterveld, D. H.; Reimer, P. E.; Schulte, E.; Zeidman, B.; Physics

    2007-01-01

    The parity-violating asymmetry in e-2H deep inelastic scattering (DIS) can be used to extract the weak neutral-current coupling constants C 2q . A measurement of this asymmetry at two Q 2 values is planned at Jefferson Lab. Results from this experiment will provide a value of 2C 2u - C 2d to a precision of {+-}0.03, a factor of eight improvement over our current knowledge. If all hadronic effects can be understood, this result will provide information on possible extensions of the Standard Model, complementary to other experiments dedicated to new physics searches. Presented here are the physics motivation, experimental setup, potential hadronic effects and their implications, and the future of PV DIS at Jefferson Lab.

  18. Phenomenological analysis of azimuthal asymmetries in unpolarized semi-inclusive deep inelastic scattering

    NASA Astrophysics Data System (ADS)

    Barone, V.; Boglione, M.; Gonzalez Hernandez, J. O.; Melis, S.

    2015-04-01

    We present a phenomenological analysis of the cos ϕ and cos 2 ϕ asymmetries in unpolarized semi-inclusive deep inelastic scattering, based on the recent multidimensional data released by the COMPASS and HERMES collaborations. In the transverse-momentum-dependent framework, valid at relatively low transverse momenta, these asymmetries arise from intrinsic transverse momentum and transverse spin effects, and from their correlations. The role of the Cahn and Boer-Mulders effects in both azimuthal moments is explored up to order 1 /Q . As the kinematics of the present experiments is dominated by the low-Q2 region, higher-twist contributions turn out to be important, affecting the results of our fits.

  19. Concentration dependence of vibrational properties of bioprotectant/water mixtures by inelastic neutron scattering.

    PubMed

    Magazù, S; Migliardo, F; Ramirez-Cuesta, A J

    2007-02-22

    Neutron scattering has been demonstrated to be a powerful tool for characterizing the structure and dynamics of biological molecules and for investigating the physical and chemical mechanisms of biophysical processes. The aim of the present work is to investigate by inelastic neutron scattering (INS) the vibrational behaviour of a class of bioprotectant systems, such as homologous disaccharides, trehalose, maltose and sucrose, in water mixtures. INS measurements have been performed on trehalose/H2O, maltose/H2O and sucrose/H2O mixtures at very low temperature as a function of concentration by using the thermal original spectrometer with cylindrical analyzers (TOSCA) spectrometer at the ISIS Facility (DRAL, UK). The findings allow the analyses of the vibrational features of the INS spectra in order to study the effect of disaccharides on the H2O hydrogen-bonded tetrahedral network. The obtained neutron scattering findings point out that disaccharides, and in particular trehalose, have a destructuring effect on the water tetrahedral network, as emphasized by the analysis of the librational modes region from 50 to 130 meV energy transfer. On the other hand, the analysis of the bending modes region (130-225 meV) shows a locally ordered structure in the disaccharide/H2O mixtures.Finally, the observed experimental evidences are linked to the different bioprotective effectiveness of disaccharides as a function of concentration.

  20. Lattice dynamics and molecular rotations in solid hydrogen deuteride: Inelastic neutron scattering study

    NASA Astrophysics Data System (ADS)

    Colognesi, D.; Formisano, F.; Ramirez-Cuesta, A. J.; Ulivi, L.

    2009-04-01

    In the present paper we report inelastic neutron scattering measurements on solid low-pressure hydrogen deuteride at three different temperatures (between 4.5 and 15.6 K) using the time-of-flight spectrometers BRISP at ILL (France) and TOSCA-II at ISIS, RAL (UK). The measured double-differential cross sections give access to the proton component of the HD self-inelastic structure factor. Processed BRISP data were employed to verify the applicability of the generalized Young and Koppel model to solid HD in our kinematic range and to obtain the mean-square displacement of the molecular centers of mass. In addition, a large broadening of the first two rotational peaks was observed. A reasonable result for the density of phonon states from TOSCA-II data has been obtained, although a rigorous extraction was not possible, due to the overlap among the various spectral components. The intensity loss in the extracted density of phonon states was interpreted as the effect the phonon-roton resonance in solid hydrogen deuteride. Finally the two Bose-corrected moments of the HD phonon spectrum, related to the molecular mean-square displacement and mean kinetic energy, were simulated through a path integral Monte Carlo code. The former quantity was compared to the mentioned experimental estimates.

  1. Inelastic Neutron Scattering Studies of the Dynamics of Glass-Forming Materials in Confinement

    NASA Astrophysics Data System (ADS)

    Zorn, Reiner

    2015-03-01

    The study of the dynamics of glass-forming liquids in nanoscopic confinement may contribute to the understanding of the glass transition. Especially, the question of a cooperativity length scale may be addressed. In this presentation, results obtained by inelastic neutron scattering are presented. The first experiments were done to study the α relaxation of glass-forming liquids and polymers in nanoporous silica. Neutron scattering is a suitable method to study such composite materials because the scattering of the liquid component can be emphasized by proper choice of isotopes. By combining time-of-flight spectroscopy and backscattering spectroscopy it is possible to cover the large dynamical range spanned by the dynamics of glass-forming materials. The experiments demonstrated a broadening of the spectrum of relaxation times with faster as well as slower components compared to the bulk. In later experiments `soft' confinement in a microemulsion was used to reduce surface effects. In this system a definite acceleration of the dynamics was observed. In all cases the glass-specific fast vibrational dynamics (boson peak) was also studied, revealing a characteristic confinement dependence which allows conclusions on its nature. Finally, studies were carried out on polymers by neutron spin echo spectroscopy with the aim of observing the confinement effect on polymer specific dynamics (Rouse motion). These studies showed that a comparatively simple model is able to explain the deviation from bulk behavior.

  2. Resonant inelastic hard x-ray scattering with diced analyzer crystals and position-sensitive detectors

    SciTech Connect

    Huotari, S.; Albergamo, F.; Vanko, Gy.; Verbeni, R.; Monaco, G.

    2006-05-15

    A novel design of a high-resolution spectrometer is proposed for emission spectroscopy and resonant inelastic hard x-ray scattering applications. The spectrometer is based on a Rowland circle geometry with a diced analyzer crystal and a position-sensitive detector. The individual flat crystallites of the diced analyzer introduce a well-defined linear position-energy relationship within the analyzer focus. This effect can be exploited to measure emission spectra with an unprecedented resolution. For demonstration, a spectrometer was constructed using a diced Si(553) analyzer working at the Cu K edge with an intrinsic resolution of 60 meV. With the proposed design, spectrometers operating at the K edges of 3d transition metals can have intrinsic resolutions below 100 meV even with analyzer crystals not working in Bragg-backscattering conditions.

  3. Collective dynamics in fully hydrated phospholipid bilayers studied by inelastic x-ray scattering.

    PubMed

    Chen, S H; Liao, C Y; Huang, H W; Weiss, T M; Bellisent-Funel, M C; Sette, F

    2001-01-22

    The short wavelength density fluctuation of DLPC (dilaurylphosphatidylcholine) bilayers close to full hydration has been studied by the inelastic x-ray scattering technique below and above the main transition temperature. The analysis based on a generalized three effective eigenmode theory allows us to construct the dispersion relation of the high frequency sound mode for the first time. The marked softening of the excitation near k = 14 nm(-1), corresponding to the lipid chain-chain correlation peak in the structure factor, in the L(alpha) phase implies prevalent occurrences of short-wavelength in-plane motions of lipid chains that might be of importance for transportation of small molecules across membranes. PMID:11177926

  4. Hot background” of the mobile inelastic neutron scattering system for soil carbon analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The problem of gamma spectrum peaks identification arises when conducting soil carbon (and other elements) analysis using the mobile inelastic neutron scattering (MINS) system. Some gamma spectrum peaks could be associated with radioisotopes appearing due to neutron activation of both the MINS syste...

  5. Application of Geant4 simulation for analysis of soil carbon inelastic neutron scattering measurements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inelastic neutron scattering (INS) was applied to determine soil carbon content. Due to non-uniform soil carbon depth distribution, the correlation between INS signals with some soil carbon content parameter is not obvious; however, a proportionality between INS signals and average carbon weight per...

  6. Monte-Carlo simulation of soil carbon measurements by inelastic neutron scattering

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Measuring soil carbon is critical for assessing the potential impact of different land management practices on carbon sequestration. The inelastic neutron scattering (INS) of fast neutrons (with energy around 14 MeV) on carbon-12 nuclei produces gamma rays with energy of 4.43 MeV; this gamma flux ca...

  7. Longitudinal Polarization of {lambda} and {lambda}-bar Hyperons in Deep-Inelastic Scattering at COMPASS

    SciTech Connect

    Sapozhnikov, M. G.

    2007-06-13

    The longitudinal polarization of {lambda} and {lambda}-bar hyperons produced in deep-inelastic scattering of 160 GeV/c polarized positive muons is studied in the COMPASS (CERN NA58) experiment. Preliminary results on the longitudinal polarization of {lambda} and {lambda}-bar from data collected during the 2003 run are presented.

  8. Polarised HIGH-Q2 Deep Inelastic Scattering at Hera-Ii

    NASA Astrophysics Data System (ADS)

    Nagano, K.

    2005-04-01

    The cross sections for neutral and charged-current deep inelastic scattering with longitudinally polarised e+p collisions were first measured at a luminosity-averaged positive polarisation of about 30% and at a negative polarisation of about -40%. The parity-violating nature of the weak charged-current interaction was clearly observed, which is the first direct measurement at large energies.

  9. Reply to comment by Thomas on ''On rainbow scattering in inelastic molecular collisions''

    SciTech Connect

    Bowman, J.M.; Lee, K.T.

    1981-02-15

    The comments of Thomas/sup 1/ on the location of rainbows in inelastic molecular scattering of Ref. 2 are discussed and evaluated. It is contended that more insight into the nature of reainbows in rotatinally inelstic collisions is obtained by using the arguments in ref. 2. (AIP)

  10. Probing the Structure of Ionic Liquid Surfaces by Rotationally and Electronically Inelastic Scattering of no

    NASA Astrophysics Data System (ADS)

    Ziemkiewicz, M. P.; Zutz, A.; Nesbitt, D. J.

    2012-06-01

    Room temperature ionic liquids (RTIL’s) are a highly diverse class of materials with many potential technological applications. They are candidates for use in advanced electrolytes, green solvents, and supported liquid membranes for CO_2 sequestration. We present studies where inelastic scattering of high or low velocity nitric oxide provides insight into the microscopic structure of these complex surfaces. As an open shell diatomic, jet-cooled NO [^2π1/2(J = 0.5)] features both molecular and electronic collision dynamics as seen by probing scattered rotational and spin-orbit distributions respectively. These studies show substantial variation in degree of rotational and electronic excitation as ionic liquid identity is varied. Also, surface heating is found to have a strong effect on scattered spin-orbit branching, possibly due to the dependence of surface structure on temperature. This is discussed in terms of a picture where the electronic degree of freedom may serve as a sensitive measure of the cationic versus anionic nature of the top few layers of this material.

  11. Inelastic and reactive scattering of hyperthermal atomic oxygen from amorphous carbon

    NASA Technical Reports Server (NTRS)

    Minton, Timothy K.; Nelson, Christine M.; Brinza, David E.; Liang, Ranty H.

    1991-01-01

    The reaction of hyperthermal oxygen atoms with an amorphous carbon-13 surface was studied using a modified universal crossed molecular beams apparatus. Time-of-flight distributions of inelastically scattered O-atoms and reactively scattered CO-13 and CO2-13 were measured with a rotatable mass spectrometer detector. Two inelastic scattering channels were observed, corresponding to a direct inelastic process in which the scattered O-atoms retain 20 to 30 percent of their initial kinetic energy and to a trapping desorption process whereby O-atoms emerge from the surface at thermal velocities. Reactive scattering data imply the formation of two kinds of CO products, slow products whose translational energies are determined by the surface temperature and hyperthermal (Approx. 3 eV) products with translational energies comprising roughly 30 percent of the total available energy (E sub avl), where E sub avl is the sum of the collision energy and the reaction exothermicity. Angular data show that the hyperthermal CO is scattered preferentially in the specular direction. CO2 product was also observed, but at much lower intensities than CO and with only thermal velocities.

  12. Simultaneous, noninvasive observation of elastic scattering, fluorescence and inelastic scattering as a monitor of blood flow and hematocrit in human fingertip capillary beds

    NASA Astrophysics Data System (ADS)

    Chaiken, Joseph; Goodisman, Jerry; Deng, Bin; Bussjager, Rebecca J.; Shaheen, George

    2009-09-01

    We report simultaneous observation of elastic scattering, fluorescence, and inelastic scattering from in vivo near-infrared probing of human skin. Careful control of the mechanical force needed to obtain reliable registration of in vivo tissue with an appropriate optical system allows reproducible observation of blood flow in capillary beds of human volar side fingertips. The time dependence of the elastically scattered light is highly correlated with that of the combined fluorescence and Raman scattered light. We interpret this in terms of turbidity (the impeding effect of red blood cells on optical propagation to and from the scattering centers) and the changes in the volume percentages of the tissues in the irradiated volume with normal homeostatic processes. By fitting to a model, these measurements may be used to determine volume fractions of plasma and RBCs.

  13. Precise QCD Predictions for the Production of Dijet Final States in Deep Inelastic Scattering.

    PubMed

    Currie, James; Gehrmann, Thomas; Niehues, Jan

    2016-07-22

    The production of two-jet final states in deep inelastic scattering is an important QCD precision observable. We compute it for the first time to next-to-next-to-leading order (NNLO) in perturbative QCD. Our calculation is fully differential in the lepton and jet variables and allows one to impose cuts on the jets in both the laboratory and the Breit frame. We observe that the NNLO corrections are moderate in size, except at kinematical edges, and that their inclusion leads to a substantial reduction of the scale variation uncertainty on the predictions. Our results will enable the inclusion of deep inelastic dijet data in precision phenomenology studies. PMID:27494466

  14. Precise QCD Predictions for the Production of Dijet Final States in Deep Inelastic Scattering

    NASA Astrophysics Data System (ADS)

    Currie, James; Gehrmann, Thomas; Niehues, Jan

    2016-07-01

    The production of two-jet final states in deep inelastic scattering is an important QCD precision observable. We compute it for the first time to next-to-next-to-leading order (NNLO) in perturbative QCD. Our calculation is fully differential in the lepton and jet variables and allows one to impose cuts on the jets in both the laboratory and the Breit frame. We observe that the NNLO corrections are moderate in size, except at kinematical edges, and that their inclusion leads to a substantial reduction of the scale variation uncertainty on the predictions. Our results will enable the inclusion of deep inelastic dijet data in precision phenomenology studies.

  15. Diffractive limit approach to elastic scattering and inelastic diffraction of high-energy hadrons

    NASA Astrophysics Data System (ADS)

    Małecki, Andrzej

    1996-09-01

    An approach to inelastic diffraction based on the concept of equivalence of diffractive states is developed. In the classical description of Good and Walker, the inelastic diffraction originates from the diversity of elastic scattering amplitudes in the initial and final state Δt. We consider a multichannel correction, accounting for intermediate transitions inside the equivalence class. This correction can be factorized yielding the diffraction amplitude in the form NΔt, to be taken in the ``diffractive limit'' N-->∞, Δt-->0 such that NΔt is finite. We analyze elastic scattering and the inclusive inelastic diffraction cross sections for p-p and p-p>¯ collisions, in the range of c.m. energy √s=20-1800 GeV. We claim that the angular distribution of the inclusive inelastic diffraction at small momentum transfers is determined by elastic scattering in the transition region between the forward peak and the minimum. This is successfully verified in experiment. The detailed comparison with the Good-Walker description, with emphasis on the advantages of our approach, is presented.

  16. Accurate Calculations of Rotationally Inelastic Scattering Cross Sections Using Mixed Quantum/Classical Theory.

    PubMed

    Semenov, Alexander; Babikov, Dmitri

    2014-01-16

    For computational treatment of rotationally inelastic scattering of molecules, we propose to use the mixed quantum/classical theory, MQCT. The old idea of treating translational motion classically, while quantum mechanics is used for rotational degrees of freedom, is developed to the new level and is applied to Na + N2 collisions in a broad range of energies. Comparison with full-quantum calculations shows that MQCT accurately reproduces all, even minor, features of energy dependence of cross sections, except scattering resonances at very low energies. The remarkable success of MQCT opens up wide opportunities for computational predictions of inelastic scattering cross sections at higher temperatures and/or for polyatomic molecules and heavier quenchers, which is computationally close to impossible within the full-quantum framework.

  17. Inelastic scattering of NO from Ag(111): Internal state, angle, and velocity resolved measurements

    SciTech Connect

    Rettner, C.T.; Kimman, J.; Auerbach, D.J. )

    1991-01-01

    We have determined the velocity distributions of individual quantum states of NO scattering from Ag(111) at specific scattering angles {theta}{sub {ital f}} using molecular beam techniques to control the incidence energy {ital E}{sub {ital i}} and angle {theta}{sub {ital i}}. We find that the mean energies of scattered species {ital E}{sub {ital f}} depend weakly on {theta}{sub {ital f}} at low collision energies, but become increasingly independent of this parameter as {ital E}{sub {ital i}} approaches 1.0 eV. This is true for all final rotation states {ital J}. The previously reported insensitivity of the final kinetic energy to {ital J} is found to apply at all scattering angles, so that {ital E}{sub {ital f}} vs {theta}{sub {ital f}} curves for high {ital J} fall only slightly below those for low {ital J}. This system is highly translationally inelastic at high incidence energies, with up to 55% of {ital E}{sub {ital i}} being lost to phonons at {ital E}{sub {ital i}}=1.0 eV. Angular distributions are relatively insensitive to {ital J} at low {ital E}{sub {ital i}} , but for high {ital E}{sub {ital i}} the peak flux is found to shift away from the surface normal as {ital E}{sub {ital i}} increases. The effect of the surface temperature only becomes apparent at low incidence energies. A search for supernumerary rotational rainbows reveals no discernible oscillations even for the lowest surface temperatures. We believe that these supernumerary oscillations may be damped by surface corrugation'' effects for this system. Discussion focuses on the observed anticorrelation between kinetic energy transfer to phonons and to rotation, the extent to which parallel momentum is conserved in this system, and energy-angle scaling laws for energy transfer.

  18. Study of Low Energy Electron Inelastic Scattering Mechanisms Using Spin Sensitive Techniques

    NASA Astrophysics Data System (ADS)

    Hsu, Hongbing

    1995-01-01

    Spin sensitive electron spectroscopies were used to study low energy electron inelastic scattering from metal surfaces and thin films. In these experiments, a beam of spin polarized electrons from a GaAs source is directed on the sample surface, and the spin polarization and intensity are measured as a function of energy loss and scattering angle by a Mott electron polarimeter coupled with a concentric hemispherical energy analyzer. Systematic studies of the angular dependence of inelastically scattered electrons were conducted on a Cu(100) surface, and Mo/Cu(100), non-magnetized Fe/Cu(100), and Co/Cu(100) films. The polarization and intensity of scattered electrons were measured as function of energy loss and scattering angle. Further studies were also conducted on Ag(100) surface and amorphous Cu/Ag(100) films. From the experimental results, the angular distributions of dipole and impact scattered electrons can be determined individually and both are found to peak in the specular scattering direction. Preliminary studies were conducted on magnetized Co/Cu(100) films. The spin dependent scattering intensity asymmetry was measured, with a clearly observable peak at energy loss of ~1 eV, which coincides with the band splitting. The polarizations of secondary electrons produced by an unpolarized primary beam were also measured. The polarizations can be related to the band polarization of magnetized cobalt films.

  19. Elastic and inelastic scattering of positrons in gases and solids

    NASA Technical Reports Server (NTRS)

    Mcgowan, J. W.

    1972-01-01

    Three apparatuses were designed and built: The first, which is now operative, was designed to study the details of positron thermalization in solids and the subsequent emission of the low energy positrons from moderating foils; The second apparatus now under test is a positron bottle similar in design to an electron trap. It was built to store positrons at a fixed energy and to look at the number of stored positrons (storage time) as a function of a scattering gas in the vacuum chamber. The third apparatus is a crossed beam apparatus where positron-, alkali scattering will be studied. Much of the apparatus is now under test with electrons.

  20. Fully quantum state-resolved inelastic scattering of NO(X) + Kr: Differential cross sections and product rotational alignment

    SciTech Connect

    Brouard, M. Chadwick, H.; Gordon, S. D. S.; Hornung, B.; Nichols, B.; Kłos, J.; Aoiz, F. J.; Stolte, S.

    2014-10-28

    Fully quantum state selected and resolved inelastic scattering of NO(X) by krypton has been investigated. Initial Λ-doublet state selection is achieved using an inhomogeneous hexapole electric field. Differential cross sections and even-moment polarization dependent differential cross sections have been obtained at a collision energy of 514 cm{sup −1} for both spin-orbit and parity conserving and changing collisions. Experimental results are compared with those obtained from quantum scattering calculations and are shown to be in very good agreement. Hard shell quantum scattering calculations are also performed to determine the effects of the different parts of the potential on the scattering dynamics. Comparisons are also made with the NO(X) + Ar system.

  1. Fully quantum state-resolved inelastic scattering of NO(X) + Kr: differential cross sections and product rotational alignment.

    PubMed

    Brouard, M; Chadwick, H; Gordon, S D S; Hornung, B; Nichols, B; Kłos, J; Aoiz, F J; Stolte, S

    2014-10-28

    Fully quantum state selected and resolved inelastic scattering of NO(X) by krypton has been investigated. Initial Λ-doublet state selection is achieved using an inhomogeneous hexapole electric field. Differential cross sections and even-moment polarization dependent differential cross sections have been obtained at a collision energy of 514 cm(-1) for both spin-orbit and parity conserving and changing collisions. Experimental results are compared with those obtained from quantum scattering calculations and are shown to be in very good agreement. Hard shell quantum scattering calculations are also performed to determine the effects of the different parts of the potential on the scattering dynamics. Comparisons are also made with the NO(X) + Ar system. PMID:25362298

  2. Final-state interactions in inclusive deep-inelastic scattering from the deuteron

    DOE PAGESBeta

    Cosyn, Wim; Melnitchouk, Wally; Sargsian, Misak M.

    2014-01-16

    We explore the role of final-state interactions (FSI) in inclusive deep-inelastic scattering from the deuteron. Relating the inclusive cross section to the deuteron forward virtual Compton scattering amplitude, a general formula for the FSI contribution is derived in the generalized eikonal approximation, utilizing the diffractive nature of the effective hadron-nucleon interaction. The calculation uses a factorized model with a basis of three resonances with mass W~<2 GeV and a continuum contribution for larger W as the relevant set of effective hadron states entering the final-state interaction amplitude. The results show sizeable on-shell FSI contributions for Bjorken x ~> 0.6 andmore » Q2 < 10 GeV2 increasing in magnitude for lower Q2, but vanishing in the high-Q2 limit due to phase space constraints. The off-shell rescattering contributes at x ~> 0.8 and is taken as an uncertainty on the on-shell result.« less

  3. Toroidal silicon polarization analyzer for resonant inelastic x-ray scattering

    NASA Astrophysics Data System (ADS)

    Gao, Xuan; Casa, Diego; Kim, Jungho; Gog, Thomas; Li, Chengyang; Burns, Clement

    2016-08-01

    Resonant Inelastic X-ray Scattering (RIXS) is a powerful probe for studying electronic excitations in materials. Standard high energy RIXS measurements do not measure the polarization of the scattered x-rays, which is unfortunate since it carries information about the nature and symmetry of the excitations involved in the scattering process. Here we report the fabrication of thin Si-based polarization analyzers with a double-concave toroidal surface, useful for L-edge RIXS studies in heavier atoms such as the 5-d transition metals.

  4. Toroidal silicon polarization analyzer for resonant inelastic x-ray scattering.

    PubMed

    Gao, Xuan; Casa, Diego; Kim, Jungho; Gog, Thomas; Li, Chengyang; Burns, Clement

    2016-08-01

    Resonant Inelastic X-ray Scattering (RIXS) is a powerful probe for studying electronic excitations in materials. Standard high energy RIXS measurements do not measure the polarization of the scattered x-rays, which is unfortunate since it carries information about the nature and symmetry of the excitations involved in the scattering process. Here we report the fabrication of thin Si-based polarization analyzers with a double-concave toroidal surface, useful for L-edge RIXS studies in heavier atoms such as the 5-d transition metals. PMID:27587100

  5. Measurement of high energy resolution inelastic proton scattering at and close to zero degrees

    NASA Astrophysics Data System (ADS)

    Tamii, A.; Fujita, Y.; Matsubara, H.; Adachi, T.; Carter, J.; Dozono, M.; Fujita, H.; Fujita, K.; Hashimoto, H.; Hatanaka, K.; Itahashi, T.; Itoh, M.; Kawabata, T.; Nakanishi, K.; Ninomiya, S.; Perez-Cerdan, A. B.; Popescu, L.; Rubio, B.; Saito, T.; Sakaguchi, H.; Sakemi, Y.; Sasamoto, Y.; Shimbara, Y.; Shimizu, Y.; Smit, F. D.; Tameshige, Y.; Yosoi, M.; Zenhiro, J.

    2009-07-01

    Measurements of inelastic proton scattering with high energy resolution at forward scattering angles including 0∘ are described. High-resolution halo-free beams were accelerated by the cyclotron complex at the Research Center for Nuclear Physics. Instrumental background events were minimized using the high-quality beam. The remaining instrumental background events were eliminated by applying a background subtraction method. As a result, clean spectra were obtained even for a heavy target nucleus such as Pb208. A high energy resolution of 20 keV (FWHM) and a scattering angle resolution of ±0.6∘ were achieved at an incident proton energy of 295 MeV.

  6. Toroidal silicon polarization analyzer for resonant inelastic x-ray scattering.

    PubMed

    Gao, Xuan; Casa, Diego; Kim, Jungho; Gog, Thomas; Li, Chengyang; Burns, Clement

    2016-08-01

    Resonant Inelastic X-ray Scattering (RIXS) is a powerful probe for studying electronic excitations in materials. Standard high energy RIXS measurements do not measure the polarization of the scattered x-rays, which is unfortunate since it carries information about the nature and symmetry of the excitations involved in the scattering process. Here we report the fabrication of thin Si-based polarization analyzers with a double-concave toroidal surface, useful for L-edge RIXS studies in heavier atoms such as the 5-d transition metals.

  7. Inelastic scattering in condensed matter with high intensity Moessbauer radiation

    SciTech Connect

    Yelon, W.B.; Schupp, G.

    1993-02-01

    The QUEGS facility at MURR has produced a number of new results and demonstrated the range of potential applications of high resolution, high intensity Moessbauer scattering. This work has been carried out by both MU and Purdue researchers and includes published results on Na, W, pentadecane, polydimethylsiloxane and other systems, manuscripts submitted on alkali halides (Phys. Rev. B) and accurate Moessbauer lineshape measurements (Phys. Rev. C), and manuscripts in preparation on glycerol, NiAl and Moessbauer spectra obtained by modulating a scattering crystal. Recently, new collaborations have been initiated which will substantially enhance our efforts. These are with W. Steiner (Vienna), G. Coddens (Saclay), and R. D. Taylor (Los Alamos). Steiner is experienced with Fe-57 Moessbauer scattering, while Coddens specializes in quasielastic neutron scattering; both of these areas naturally complement our work. R. D. Taylor has pioneered Moessbauer spectroscopy from the time of its discovery and has already made important contributions to our study of lattice dynamics and superconductivity for lead alloyed with small quantities of tin. At the same time, a significant instrument upgrade is underway, funded in part by the DOE-URIP program.

  8. CT14QED parton distribution functions from isolated photon production in deep inelastic scattering

    NASA Astrophysics Data System (ADS)

    Schmidt, Carl; Pumplin, Jon; Stump, Daniel; Yuan, C.-P.

    2016-06-01

    We describe the implementation of quantum electrodynamic (QED) evolution at leading order (LO) along with quantum chromodynamic (QCD) evolution at next-to-leading order (NLO) in the CTEQ-TEA global analysis package. The inelastic contribution to the photon parton distribution function (PDF) is described by a two-parameter ansatz, coming from radiation off the valence quarks, and based on the CT14 NLO PDFs. Setting the two parameters to be equal allows us to completely specify the inelastic photon PDF in terms of the inelastic momentum fraction carried by the photon, p0γ, at the initial scale Q0=1.295 GeV . We obtain constraints on the photon PDF by comparing with ZEUS data [S. Chekanov et al. (ZEUS Collaboration), Phys. Lett. B 687, 16 (2010)] on the production of isolated photons in deep inelastic scattering, e p →e γ +X . For this comparison we present a new perturbative calculation of the process that consistently combines the photon-initiated contribution with the quark-initiated contribution. Comparison with the data allows us to put a constraint at the 90% confidence level of p0γ≲0.14 % for the inelastic photon PDF at the initial scale of Q0=1.295 GeV in the one-parameter radiative ansatz. The resulting inelastic CT14QED PDFs will be made available to the public. In addition, we also provide CT14QEDinc PDFs, in which the inclusive photon PDF at the scale Q0 is defined by the sum of the inelastic photon PDF and the elastic photon distribution obtained from the equivalent photon approximation.

  9. Rotationally Inelastic Scattering of Quantum-State-Selected ND3 with Ar.

    PubMed

    Tkáč, Ondřej; Saha, Ashim K; Loreau, Jérôme; Parker, David H; van der Avoird, Ad; Orr-Ewing, Andrew J

    2015-06-11

    Rotationally inelastic scattering of ND3 with Ar is studied at mean collision energies of 410 and 310 cm(–1). In the experimental component of the study, ND3 molecules are prepared by supersonic expansion and subsequent hexapole state selection in the ground electronic and vibrational levels and in the jk(±) = 1(1) rotational level. A beam of state-selected ND3 molecules is crossed with a beam of Ar, and scattered ND3 molecules are detected in single final j′k′(±) quantum states using resonance enhanced multiphoton ionization spectroscopy. State-to-state differential cross sections for rotational-level changing collisions are obtained by velocity map imaging. The experimental measurements are compared with close-coupling quantum-mechanical scattering calculations performed using an ab initio potential energy surface. The computed DCSs agree well with the experimental measurements, confirming the high quality of the potential energy surface. The angular distributions are dominated by forward scattering for all measured final rotational and vibrational inversion symmetry states. This outcome is in contrast to our recent results for inelastic scattering of ND3 with He, where we observed significant amount of sideways and backward scattering for some final rotational levels of ND3. The differences between He and Ar collision partners are explained by differences in the potential energy surfaces that govern the scattering dynamics.

  10. State-to-state inelastic scattering of Stark-decelerated OH radicals with Ar atoms.

    PubMed

    Scharfenberg, Ludwig; Kłos, Jacek; Dagdigian, Paul J; Alexander, Millard H; Meijer, Gerard; van de Meerakker, Sebastiaan Y T

    2010-09-28

    The Stark deceleration method exploits the concepts of charged particle accelerator physics to produce molecular beams with a tunable velocity. These tamed molecular beams offer interesting perspectives for precise crossed beam scattering studies as a function of the collision energy. The method has advanced sufficiently to compete with state-of-the-art beam methods that are used for scattering studies throughout. This is demonstrated here for the scattering of OH radicals (X(2)Pi(3/2), J = 3/2, f) with Ar atoms, a benchmark system for the scattering of open-shell molecules with atoms. Parity-resolved integral state-to-state inelastic scattering cross sections are measured at collision energies between 80 and 800 cm(-1). The threshold behavior and collision energy dependence of 13 inelastic scattering channels is accurately determined. Excellent agreement is obtained with the cross sections predicted by close-coupling scattering calculations based on the most accurate ab initio OH + Ar potential energy surfaces to date. PMID:20657906

  11. Vibrational dynamics of plant light-harvesting complex LHC II investigated by quasi- and inelastic neutron scattering

    NASA Astrophysics Data System (ADS)

    Golub, Maksym; Irrgang, Klaus-Dieter; Rusevich, Leonid; Pieper, Jörg

    2015-01-01

    Vibrational dynamics of the light-harvesting complex II (LHC II) from spinach was investigated by quasi- and inelastic neutron scattering (QENS and INS) at three different temperatures of 80, 160, and 285 K. QENS/INS spectra of solubilised LHC II and of the corresponding buffer solution were obtained separately and exhibit characteristic inelastic features. After subtraction of the buffer contribution, the INS spectrum of LHC II reveals a distinct Boson peak at ˜ 2.5 meV at 80 K that shifts towards lower energies if the temperature is increased to 285 K. This effect is interpreted in terms of a "softening" of the protein matrix along with the dynamical transition at ˜ 240 K. Our findings indicate that INS is a valuable method to obtain the density of vibrational states not only at cryogenic, but also at physiological temperatures.

  12. Producing a compound Nucleus via Inelastic Scattering: The 90Zr(alpha,alpha')90Zr* Case

    SciTech Connect

    Escher, J E; Dietrich, F S

    2008-05-23

    In a Surrogate reaction a compound nucleus is produced via a direct reaction (pickup, stripping, or inelastic scattering). For a proper application of the Surrogate approach it is necessary to predict the resulting angular momentum and parity distribution in the compound nucleus. A model for determining these distributions is developed for the case of inelastic alpha scattering off a spherical nucleus. The focus is on obtaining a first, simple description of the direct-reaction process that produces the compound nucleus and on providing the basis for a more complete treatment of the problem. The approximations employed in the present description are discussed and the extensions required for a more rigorous treatment of the problem are outlined. To illustrate the formalism, an application to {sup 90}Zr({alpha},{alpha}{prime}){sup 90}Zr* is presented.

  13. D^* production in deep-inelastic scattering at low Q^2

    SciTech Connect

    Jung, Andreas W.; /Fermilab

    2011-07-01

    Inclusive production of D* mesons in deep-inelastic scattering at HERA is studied in the range 5 < Q{sup 2} < 100 GeV{sup 2} of the photon virtuality and 0.02 < y < 0.70 of the inelasticity of the scattering process. The visible range for the D* meson is p{sub T} (D*) > 1.25 GeV and |{eta}(D*)| < 1.8. The data were taken with the H1 detector in the years 2004 to 2007 and correspond to an integrated luminosity of 347 pb{sup -1}. Single and double differential cross sections are measured. The results are compared to QCD predictions.

  14. Inelastic scattering of 72,74Ni off a proton target

    NASA Astrophysics Data System (ADS)

    Cortés, M. L.; Doornenbal, P.; Obertelli, A.; Pietralla, N.; Werner, V.; Authelet, G.; Baba, H.; Calvet, D.; Château, F.; Corsi, A.; Delbart, A.; Gheller, J.-M.; Gillibert, A.; Isobe, T.; Lapoux, V.; Louchart, C.; Matsushita, M.; Momiyama, S.; Motobayashi, T.; Niikura, M.; Otsu, H.; Péron, C.; Peyaud, A.; Pollacco, E. C.; Roussé, J.-Y.; Sakurai, H.; Santamaria, C.; Sasano, M.; Shiga, Y.; Takeuchi, S.; Taniuchi, R.; Uesaka, T.; Wang, H.; Yoneda, K.; Browne, F.; Chung, L. X.; Dombradi, Zs; Franchoo, S.; Giacoppo, F.; Gottardo, A.; Hadynska-Klek, K.; Korkulu, Z.; Koyama, S.; Kubota, Y.; Lee, J.; Lettmann, M.; Lozeva, R.; Matsui, K.; Miyazaki, T.; Nishimura, S.; Olivier, L.; Ota, S.; Patel, Z.; Sahin, E.; Shand, C. M.; Söderström, P.-A.; Stefan, I.; Steppenbeck, D.; Sumikama, T.; Suzuki, D.; Vajta, Zs; Wu, J.; Xu, Z.

    2016-06-01

    Inelastic scattering of 72,74Ni off a proton target was performed at RIBF, RIKEN, Japan. The isotopes were produced by the fission of 238U on a thick Beryllium target and were then selected and identified on an event-by-event basis using the BigRIPS separator. Selected isotopes were focused onto the liquid hydrogen target of the MINOS device and gamma rays from the reactions were measured with the DALI2 array. The energy of the ions in the middle of the target was 213 MeV/u. Outgoing particles were identified using the ZeroDegree spectrometer. Here, we report on the current status of the data analysis and preliminary results for the proton inelastic scattering cross sections for both isotopes.

  15. Self-dynamics of hydrogen gas as probed by means of inelastic neutron scattering

    NASA Astrophysics Data System (ADS)

    Guarini, Eleonora; Orecchini, Andrea; Formisano, Ferdinando; Demmel, Franz; Petrillo, Caterina; Sacchetti, Francesco; Bafile, Ubaldo; Barocchi, Fabrizio

    2005-12-01

    The neutron double-differential cross-section of molecular hydrogen at low density has been measured at two rather low scattering angles and different final neutron energies by means of three-axis spectrometry. This first inelastic scattering determination of the single-particle roto-translational dynamics of room temperature H2 allows for a detailed test of the theoretical modelling of the spectral line-shapes of such a fundamental molecule, performed by referring both to a careful quantum-mechanical treatment and to a simpler semi-classical approximation. A comprehensive report on the neutron measurements and data analysis is presented, along with an overview of the theories used for comparison with the experimental results. An encouraging picture of the present capabilities in the calculation of the true dynamic response of hydrogen gas to slow and thermal neutrons is obtained, opening new perspectives for accurate data calibration in inelastic neutron spectroscopy, with special relevance for small-angle experiments.

  16. Resonant Inelastic X-Ray Scattering Response of the Kitaev Honeycomb Model

    NASA Astrophysics Data System (ADS)

    Halász, Gábor B.; Perkins, Natalia B.; van den Brink, Jeroen

    2016-09-01

    We calculate the resonant inelastic X-ray scattering (RIXS) response of the Kitaev honeycomb model, an exactly solvable quantum-spin-liquid model with fractionalized Majorana and flux excitations. We find that the fundamental RIXS channels, the spin-conserving (SC) and the non-spin-conserving (NSC) ones, do not interfere and give completely different responses. SC-RIXS picks up exclusively the Majorana sector with a pronounced momentum dispersion, whereas NSC-RIXS also creates immobile fluxes, thereby rendering the response only weakly momentum dependent, as in the spin structure factor measured by inelastic neutron scattering. RIXS can therefore pick up the fractionalized excitations of the Kitaev spin liquid separately, making it a sensitive probe to detect spin-liquid character in potential material incarnations of the Kitaev honeycomb model.

  17. Multi-jet production rates in deep-inelastic muon-proton scattering

    SciTech Connect

    Salgado, C.W. )

    1992-02-01

    Measurements of forward multi-jet production rates in deep-inelastic muon-proton scattering are presented. Data were taken with a 490 GeV muon beam incident on a hydrogen target. Jets were defined using the JADE jet finding algorithm. The measured rates are presented as function of W, the hadronic center-of-mass energy and the jet resolution parameter, [ital y][sub [ital cut

  18. Toward a QCD analysis of jet rates in deep-inelastic Muon-Proton scattering

    SciTech Connect

    Salgado, C.W.; E665 Collaboration

    1993-08-01

    Measurements of multi-jet production rates in deep-inelastic Muon-Proton scattering at Fermilab-E665 are presented. Jet rates defined by the JADE clustering algorithm are compared to perturbative Quantum chromodynamics (PQCD) and different Monte Carlo model predictions. The applicability of the jet-parton duality hypothesis is studied. We obtain hadronic jet rates which are approximately a factor of two higher than PQCD predictions at the parton level. Possible causes for this discrepancy are discussed.

  19. Differences between the deformed-potential and folding-model descriptions of inelastic nuclear scattering

    SciTech Connect

    Hnizdo, V. )

    1994-08-01

    The differences between the deformed-potential and folding-model descriptions of inelastic nuclear scattering, attention to which has been called recently by Beene, Horen, and Satchler [Phys. Rev. C 48, 3128 (1993)], were pointed out already some time ago by contrasting the rules of equal deformation lengths and equal normalized multipole moments for the optical potential and the underlying nucleon distribution of the excited nucleus.

  20. Test of factorization in diffractive deep inelastic scattering and photoproduction at HERA

    SciTech Connect

    Polifka, Richard

    2015-04-10

    The QCD factorization theorem in diffraction is tested by comparing diffractive jet production data to QCD predictions based on fits to inclusive diffractive cross section data. H1 measured dijet production with a leading proton detected in the Very Forward Proton Spectrometer (VFPS), both in deep-inelastic scattering and in photoproduction. The DIS measurements are complemented by measurements of dijet production with an associated rapidity gap and in a data sample selected with a leading proton in the Forward Proton Spectrometer (FPS)

  1. Structure and dynamics of cadmium telluride studied by x-ray and inelastic neutron scattering

    SciTech Connect

    Niedziela, Jennifer L; Stone, Matthew B

    2014-01-01

    We present a combined study of density functional theory, x-ray diffraction, and inelastic neutron scattering examining the temperature dependent structure and lattice dynamics of commercially available cadmium telluride. A subtle change in the structure is evinced near 80~K, which manifests also in the measured phonon density of states. There is no change to the long-range ordered structure. The implications of the change in relation to structural defects are discussed.

  2. Structure and dynamics of cadmium telluride studied by x-ray and inelastic neutron scattering

    SciTech Connect

    Niedziela, J. L.; Stone, M. B.

    2014-09-08

    We present a combined study of density functional theory, x-ray diffraction, and inelastic neutron scattering examining the temperature dependent structure and lattice dynamics of commercially available cadmium telluride. A subtle change in the structure is evinced near 80 K, which manifests also in the measured phonon density of states. There is no change to the long-range ordered structure. The implications of the change in relation to structural defects are discussed.

  3. "Hot background" of the mobile inelastic neutron scattering system for soil carbon analysis.

    PubMed

    Kavetskiy, Aleksandr; Yakubova, Galina; Prior, Stephen A; Torbert, H Allen

    2016-01-01

    The problem of gamma spectrum peak identification arises when conducting soil carbon analysis using the inelastic neutron scattering (INS) system. Some spectral peaks could be associated with radioisotopes appearing due to neutron activation of both the measurement system and soil samples. The investigation of "hot background" gamma spectra from the construction materials, whole measurement system, and soil samples over time showed that activation of (28)Al isotope can contribute noticeable additions to the soil neutron stimulated gamma spectra. PMID:26595773

  4. Anomalous vibrational modes in acetanilide as studied by inelastic neutron scattering

    NASA Astrophysics Data System (ADS)

    Barthes, Mariette; Eckert, Juegen; Johnson, Susanna W.; Moret, Jacques; Swanson, Basil I.; Unkefer, Clifford J.

    1992-10-01

    A study of the anomalous modes in acetanilide and five deuterated derivatives by incoherent inelastic neutron scattering is reported. These data show that the dynamics of the amide and methyl groups influence each other. In addition, the anomalous temperature behaviour of the NH out-of-plane bending mode is confirmed. These observations suggest that the self-trapping mechanism in ACN may be more complex than hitherto assumed.

  5. Measurements of transverse momentum in semi-inclusive deep-inelastic scattering at CLAS

    SciTech Connect

    K.A. Griffioen

    2012-12-01

    With mounting experimental evidence that only a small fraction of the proton's spin comes from the spins of its quarks and gluons, the quest for orbital angular momentum has begun. The parton distributions relevant to this depend on transverse quark momenta. Recent CLAS semi-inclusive deep-inelastic scattering measurements probe these new transverse-momentum-dependent parton distributions using longitudinally polarized beams and targets and detecting {pi}{sup +},{pi}{sup -} and {pi}{sup 0} in the final state.

  6. Shadowing in the muon-xenon inelastic scattering cross section at 490 GeV

    NASA Astrophysics Data System (ADS)

    Adams, M. R.; Aïd, S.; Anthony, P. L.; Baker, M. D.; Bartlett, J.; Bhatti, A. A.; Braun, H. M.; Busza, W.; Carroll, T. J.; Conrad, J. M.; Coutrakon, G.; Davisson, R.; Derado, I.; Dhawan, S. K.; Dougherty, W.; Dreyer, T.; Dziunikowska, K.; Eckardt, V.; Ecker, U.; Erdmann, M.; Eskreys, A.; Fang, G.; Figiel, J.; Gebauer, H. J.; Geesaman, D. F.; Gilman, R.; Green, M. C.; Haas, J.; Halliwell, C.; Hanlon, J.; Hantke, D.; Hughes, V. W.; Jackson, H. E.; Jaffe, D. E.; Jancso, G.; Jansen, D. M.; Kaufman, S.; Kennedy, R. D.; Kirk, T.; Kobrak, H. G. E.; Krzywdzinski, S.; Kunori, S.; Lord, J. J.; Lubatti, H. J.; McLeod, D.; Magill, S.; Malecki, P.; Manz, A.; Melanson, H.; Michael, D. G.; Mohr, W.; Montgomery, H. E.; Morfin, J. G.; Nickerson, R. B.; O'Day, S.; Olkiewicz, K.; Osborne, L.; Papavassiliou, V.; Pawlik, B.; Pipkin, F. M.; Ramberg, E. J.; Röser, A.; Ryan, J. J.; Salgado, C.; Salvarani, A.; Schellman, H.; Schmitt, M.; Schmitz, N.; Schüler, K. P.; Seyerlein, H. J.; Skuja, A.; Snow, G. A.; Söldner-Rembold, S.; Steinberg, P. H.; Stier, H. E.; Stopa, P.; Swanson, R. A.; Talaga, R.; Tentindo-Repond, S.; Trost, H.-J.; Venkataramania, H.; Vidal, M.; Wilhelm, M.; Wilkes, J.; Wilson, Richard; Wittek, W.; Wolbers, S. A.; Zhao, T.; Fermilab E665 Collaboration

    1992-08-01

    Inelastic scattering of 490 GeV μ + from deuterium and xenon nuclei has been studied for xBj> s.001. The ratio of the xenon/deuterium cross section per nucleon is observed to vary with xBj, with a depletion in the kinematic range 0.001 < xBj < 0.025 which exhibits no significant Q2 dependence. An electromagnetic calorimeter was used to verify the radiative corrections.

  7. Analysis of inelastic x-ray scattering spectra of low-temperature water

    PubMed

    Liao; Chen; Sette

    2000-02-01

    We analyze a set of high-resolution inelastic x-ray scattering (IXS) spectra from H2O measured at T=259, 273, and 294 K using two different phenomenological models. Model I, called the "dynamic cage model," combines the short time in-cage dynamics described by a generalized Enskog kinetic theory with a long-time cage relaxation dynamics described by an alpha relaxation. This model is appropriate for supercooled water where the cage effect is dominant and the existence of an alpha relaxation is evident from molecular-dynamics (MD) simulation data of extended simple point charge (SPC/E) model water. Model II is essentially a generalized hydrodynamic theory called the "three effective eigenmode theory" by de Schepper et al. 11. This model is appropriate for normal liquid water where the cage effect is less prominent and there is no evidence of the alpha relaxation from the MD data. We use the model I to analyze IXS data at T=259 K (supercooled water). We successfully extract the Debye-Waller factor, the cage relaxation time from the long-time dynamics, and the dispersion relation of high-frequency sound from the short time dynamics. We then use the model II to analyze IXS data at all three temperatures, from which we are able to extract the relaxation rate of the central mode and the damping of the sound mode as well as the dispersion relation for the high-frequency sound. It turns out that the dispersion relations extracted from the two models at their respective temperatures agree with each other giving the high-frequency sound speed of 2900+/-300 m/s. This is to be compared with a slightly higher value reported previously, 3200+/-320 m/s, by analyzing similar IXS data with a phenomenological-damped harmonic oscillator model 22. This latter model has traditionally been used exclusively for the analysis of inelastic scattering spectra of water. The k-dependent sound damping and central mode relaxation rate extracted from our model analyses are compared with the known

  8. Inelastic cross sections for positron scattering from atomic hydrogen

    SciTech Connect

    Weber, M.; Hofmann, A.; Raith, W.; Sperber, W.; Jacobsen, F.; Lynn, K.G.

    1994-12-31

    Positronium formation (Ps) cross sections for positrons impinging on atomic hydrogen were measured in the impact energy range from 13eV to 255eV at the High Intensity Positron (HIP) beam at Brookhaven National Laboratory (BNL). The Ps-formation cross section was found to rise rapidly from the threshold at 6.8eV to a maximum value of (2.98 {plus_minus} 0.18) {times} 10{sup {minus}16} cm{sup 2} for {approx} 15eV positrons. By 75eV it drops below the detection limit of 0.17 {times} 10{sup {minus}16} cm{sup 2} which is the present level of statistical uncertainty. The experiment was modified to enable the measurement of doubly differential scattering cross sections.

  9. Polarized lepton deep-inelastic scattering from few-nucleon targets

    NASA Astrophysics Data System (ADS)

    Woloshyn, R. M.

    1989-06-01

    The structure functions for deep-inelastic scattering of polarized leptons from polarized few-nucleon targets (nucleon, 2H, 3He) are calculated in a parton model. Spin-dependent quark distributions constructed along the lines of Carlitz-Kaur model are used. The asymmetry for scattering from polarized 3He is small in magnitude and dominated by the neutron contribution. For 2H, cancellation between proton and neutron contributions leads to a very small asymmetry below x≈0.1. Otherwise the asymmetry is large but dominated by the proton.

  10. AdS Black Disk Model for Small-x Deep Inelastic Scattering

    NASA Astrophysics Data System (ADS)

    Cornalba, Lorenzo; Costa, Miguel S.; Penedones, João

    2010-08-01

    Using the approximate conformal invariance of QCD at high energies we consider a simple anti-de Sitter black disk model to describe saturation in deep inelastic scattering. Deep inside saturation the structure functions have the same power law scaling, FT˜FL˜x-ω, where ω is related to the expansion rate of the black disk with energy. Furthermore, the ratio FL/FT is given by the universal value (1+ω)/(3+ω), independently of the target. For γ*-γ* scattering at high energies we obtain explicit expressions and ratios for the total cross sections of transverse and longitudinal photons in terms of the single parameter ω.

  11. Longitudinal-Transverse Separation of Deep-Inelastic Scattering at Low Q² on Nucleons and Nuclei

    SciTech Connect

    Tvaskis, Vladas

    2004-12-09

    Since the early experiments at SLAC, which discovered the nucleon substructure and led to the development of the quark parton model, deep inelastic scattering (DIS) has been the most powerful tool to investigate the partonic substructure of the nucleon. After about 30 years of experiments with electron and muon beams the nucleon structure function F{sub 2}(x,Q{sup 2}) is known with high precision over about four orders of magnitude in x and Q{sup 2}. In the region of Q{sup 2} > 1 (GeV/c){sup 2} the results of the DIS measurements are interpreted in terms of partons (quarks and gluons). The theoretical framework is provided in this case by perturbative Quantum Chromo Dynamics (pQCD), which includes scaling violations, as described by the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) equations. The description starts to fail when Q{sup 2} becomes of the order of 1 (GeV/c){sup 2}, where non-perturbative effects (higher-twist effects), which are still not fully understood, become important (non-pQCD). The sensitivity for order-n twist effects increases with decreasing Q{sup 2}, since they include a factor 1/(Q{sup 2}{sup n}) (n {ge} 1).

  12. Bose condensate in superfluid sup 4 He and momentum distributions by deep inelastic scattering

    SciTech Connect

    Silver, R.N. ); Sokol, P.E. . Dept. of Physics)

    1989-01-01

    There are several reasons for the high interest in the recent experimental and theoretical progress in understanding deep inelastic neutron scattering from liquid {sup 4}He: it tests the fundamental London hypothesis of a connection between superfluidity and Bose condensation; it provides a quantitative test of ab-initio calculational methods for all systems with strong correlations which are the focus of current quantum many-body research; and it establishes the range of validity of deep inelastic scattering as a method for measuring momentum distributions. In this paper we introduce the concepts of impulse approximation in more detail, we describe recent progress in the theory for final state corrections to the impulse approximation, we present quantitative predictions for neutron scattering experiments, we compare with recent high energy pulsed neutron source experiments on liquid {sup 4}He by P. Sokol and colleagues as well as other attempts to extract the Bose condensate fraction from the neutron scattering data, and we discuss the implications of this progress for future momentum distribution experiments in other systems such as liquid {sup 3}He and quasi-elastic electron nucleus scattering. 42 refs., 23 figs.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  14. On the fine structure of spectra of the inelastic-electron-scattering cross section and the Si surface parameter

    SciTech Connect

    Parshin, A. S. Igumenov, A. Yu.; Mikhlin, Yu. L.; Pchelyakov, O. P.; Nikiforov, A. I.; Timofeev, V. A.

    2015-04-15

    Reflection electron-energy loss spectra are obtained for a series of Si samples with different crystallographic orientations, prepared under different technological conditions. Using the experimental spectra, the electron energy loss dependences of the product of the mean inelastic free path and differential inelastic electron scattering cross section are calculated. A new technique is suggested for analyzing the spectra of inelastic electron scattering cross section by simulating experimental spectra with the use of the three-parameter Tougaard universal cross section functions. The results of the simulation are used to determine the nature of loss peaks and to calculate the surface parameter.

  15. Azimuthal distributions of charged hadrons, pions, and kaons produced in deep-inelastic scattering off unpolarized protons and deuterons

    NASA Astrophysics Data System (ADS)

    Airapetian, A.; Akopov, N.; Akopov, Z.; Aschenauer, E. C.; Augustyniak, W.; Avakian, R.; Avetissian, A.; Avetisyan, E.; Belostotski, S.; Blok, H. P.; Borissov, A.; Bowles, J.; Bryzgalov, V.; Burns, J.; Capiluppi, M.; Cisbani, E.; Ciullo, G.; Contalbrigo, M.; Dalpiaz, P. F.; Deconinck, W.; De Leo, R.; De Nardo, L.; De Sanctis, E.; Diefenthaler, M.; Di Nezza, P.; Düren, M.; Elbakian, G.; Ellinghaus, F.; Fantoni, A.; Felawka, L.; Frullani, S.; Gapienko, G.; Gapienko, V.; Garibaldi, F.; Gavrilov, G.; Gharibyan, V.; Giordano, F.; Gliske, S.; Golembiovskaya, M.; Hadjidakis, C.; Hartig, M.; Hasch, D.; Hillenbrand, A.; Hoek, M.; Holler, Y.; Hristova, I.; Imazu, Y.; Ivanilov, A.; Jackson, H. E.; Jo, H. S.; Joosten, S.; Kaiser, R.; Karyan, G.; Keri, T.; Kinney, E.; Kisselev, A.; Korotkov, V.; Kozlov, V.; Kravchenko, P.; Krivokhijine, V. G.; Lagamba, L.; Lapikás, L.; Lehmann, I.; Lenisa, P.; López Ruiz, A.; Lorenzon, W.; Ma, B.-Q.; Mahon, D.; Makins, N. C. R.; Manaenkov, S. I.; Manfré, L.; Mao, Y.; Marianski, B.; Martinez de la Ossa, A.; Marukyan, H.; Miller, C. A.; Miyachi, Y.; Movsisyan, A.; Murray, M.; Nappi, E.; Naryshkin, Y.; Nass, A.; Negodaev, M.; Nowak, W.-D.; Pappalardo, L. L.; Perez-Benito, R.; Petrosyan, A.; Raithel, M.; Reimer, P. E.; Reolon, A. R.; Riedl, C.; Rith, K.; Rosner, G.; Rostomyan, A.; Rubin, J.; Ryckbosch, D.; Salomatin, Y.; Sanftl, F.; Schäfer, A.; Schnell, G.; Schüler, K. P.; Seitz, B.; Shibata, T.-A.; Stancari, M.; Statera, M.; Steijger, J. J. M.; Stewart, J.; Stinzing, F.; Terkulov, A.; Truty, R. M.; Trzcinski, A.; Tytgat, M.; Vandenbroucke, A.; Van Haarlem, Y.; Van Hulse, C.; Veretennikov, D.; Vikhrov, V.; Vilardi, I.; Wang, S.; Yaschenko, S.; Ye, Z.; Yen, S.; Yu, W.; Zagrebelnyy, V.; Zeiler, D.; Zihlmann, B.; Zupranski, P.

    2013-01-01

    The azimuthal cos⁡ϕ and cos⁡2ϕ modulations of the distribution of hadrons produced in unpolarized semi-inclusive deep-inelastic scattering of electrons and positrons off hydrogen and deuterium targets have been measured in the HERMES experiment. For the first time these modulations were determined in a four-dimensional kinematic space for positively and negatively charged pions and kaons separately, as well as for unidentified hadrons. These azimuthal dependences are sensitive to the transverse motion and polarization of the quarks within the nucleon via, e.g., the Cahn, Boer-Mulders and Collins effects.

  16. Pygmy dipole resonance in 124Sn populated by inelastic scattering of 17O

    NASA Astrophysics Data System (ADS)

    Pellegri, L.; Bracco, A.; Crespi, F. C. L.; Leoni, S.; Camera, F.; Lanza, E. G.; Kmiecik, M.; Maj, A.; Avigo, R.; Benzoni, G.; Blasi, N.; Boiano, C.; Bottoni, S.; Brambilla, S.; Ceruti, S.; Giaz, A.; Million, B.; Morales, A. I.; Nicolini, R.; Vandone, V.; Wieland, O.; Bazzacco, D.; Bednarczyk, P.; Bellato, M.; Birkenbach, B.; Bortolato, D.; Cederwall, B.; Charles, L.; Ciemala, M.; De Angelis, G.; Désesquelles, P.; Eberth, J.; Farnea, E.; Gadea, A.; Gernhäuser, R.; Görgen, A.; Gottardo, A.; Grebosz, J.; Hess, H.; Isocrate, R.; Jolie, J.; Judson, D.; Jungclaus, A.; Karkour, N.; Krzysiek, M.; Litvinova, E.; Lunardi, S.; Mazurek, K.; Mengoni, D.; Michelagnoli, C.; Menegazzo, R.; Molini, P.; Napoli, D. R.; Pullia, A.; Quintana, B.; Recchia, F.; Reiter, P.; Salsac, M. D.; Siebeck, B.; Siem, S.; Simpson, J.; Söderström, P.-A.; Stezowski, O.; Theisen, Ch.; Ur, C.; Valiente Dobon, J. J.; Zieblinski, M.

    2014-11-01

    The γ decay from the high-lying states of 124Sn was measured using the inelastic scattering of 17O at 340 MeV. The emitted γ rays were detected with high resolution with the AGATA demonstrator array and the scattered ions were detected in two segmented ΔE- E silicon telescopes. The angular distribution was measured both for the γ rays and the scattered 17O ions. An accumulation of E1 strength below the particle threshold was found and compared with previous data obtained with (γ ,γ‧) and (α ,α‧ γ) reactions. The present results of elastic scattering, and excitation of E2 and E1 states were analysed using the DWBA approach. From this comprehensive description the isoscalar component of the 1- excited states was extracted. The obtained values are based on the comparison of the data with DWBA calculations including a form factor deduced using a microscopic transition density.

  17. Inelastic and Reactive Scattering Dynamics of Hyperthermal Oxygen Atoms on Ionic Liquid Surfaces: [emim][NTf2] and [C12mim][NTf2

    NASA Astrophysics Data System (ADS)

    Wu, Bohan; Zhang, Jianming; Minton, Timothy K.; McKendrick, Kenneth G.; Slattery, John M.; Yockel, Scott; Schatz, George C.

    2011-05-01

    Collisions of hyperthermal oxygen atoms, with an average translational energy of 520 kJ mol-1, on continuously refreshed ionic liquids, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([emim][NTf2]) and 1-dodecyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([C12mim][NTf2]), were studied with the use of a beam-surface scattering technique. Time-of-flight and angular distributions of inelastically scattered O and reactively scattered OH and H2O were collected for various angles of incidence with the use of a rotatable mass spectrometer detector. For both O and OH, two distinct scattering processes were identified, which can be empirically categorized as thermal and non-thermal. Non-thermal scattering is more probable for both O and OH products. The observation of OH confirms that at least some reactive sites, presumably alkyl groups, must be exposed at the surface. The ionic liquid with the longer alkyl chain, [C12mim][NTf2], is substantially more reactive than the liquid with the shorter alkyl chain, [emim][NTf2], and proportionately much more so than would be predicted simply from stoichiometry based on the number of abstractable hydrogen atoms. Molecular dynamics models of these surfaces shed light on this change in reactivity. The scattering behavior of O is distinctly different from that of OH. However, no such differences between inelastic and reactive scattering dynamics have been seen in previous work on pure hydrocarbon liquids, in particular the benchmark, partially branched hydrocarbon, squalane (C30H62). The comparison between inelastic and reactive scattering dynamics indicates that inelastic scattering from the ionic liquid surfaces takes place predominantly at non-reactive sites that are effectively stiffer than the reactive alkyl chains, with a higher proportion of collisions sampling such sites for [emim][NTf2] than for [C12mim][NTf2].

  18. Recent Advances in Development and Applications of the Mixed Quantum/Classical Theory for Inelastic Scattering.

    PubMed

    Babikov, Dmitri; Semenov, Alexander

    2016-01-28

    A mixed quantum/classical approach to inelastic scattering (MQCT) is developed in which the relative motion of two collision partners is treated classically, and the rotational and vibrational motion of each molecule is treated quantum mechanically. The cases of molecule + atom and molecule + molecule are considered including diatomics, symmetric-top rotors, and asymmetric-top rotor molecules. Phase information is taken into consideration, permitting calculations of elastic and inelastic, total and differential cross sections for excitation and quenching. The method is numerically efficient and intrinsically parallel. The scaling law of MQCT is favorable, which enables calculations at high collision energies and for complicated molecules. Benchmark studies are carried out for several quite different molecular systems (N2 + Na, H2 + He, CO + He, CH3 + He, H2O + He, HCOOCH3 + He, and H2 + N2) in a broad range of collision energies, which demonstrates that MQCT is a viable approach to inelastic scattering. At higher collision energies it can confidently replace the computationally expensive full-quantum calculations. At low collision energies and for low-mass systems results of MQCT are less accurate but are still reasonable. A proposal is made for blending MQCT calculations at higher energies with full-quantum calculations at low energies. PMID:26618533

  19. Recent Advances in Development and Applications of the Mixed Quantum/Classical Theory for Inelastic Scattering.

    PubMed

    Babikov, Dmitri; Semenov, Alexander

    2016-01-28

    A mixed quantum/classical approach to inelastic scattering (MQCT) is developed in which the relative motion of two collision partners is treated classically, and the rotational and vibrational motion of each molecule is treated quantum mechanically. The cases of molecule + atom and molecule + molecule are considered including diatomics, symmetric-top rotors, and asymmetric-top rotor molecules. Phase information is taken into consideration, permitting calculations of elastic and inelastic, total and differential cross sections for excitation and quenching. The method is numerically efficient and intrinsically parallel. The scaling law of MQCT is favorable, which enables calculations at high collision energies and for complicated molecules. Benchmark studies are carried out for several quite different molecular systems (N2 + Na, H2 + He, CO + He, CH3 + He, H2O + He, HCOOCH3 + He, and H2 + N2) in a broad range of collision energies, which demonstrates that MQCT is a viable approach to inelastic scattering. At higher collision energies it can confidently replace the computationally expensive full-quantum calculations. At low collision energies and for low-mass systems results of MQCT are less accurate but are still reasonable. A proposal is made for blending MQCT calculations at higher energies with full-quantum calculations at low energies.

  20. A multiplexed high-resolution imaging spectrometer for resonant inelastic soft X-ray scattering spectroscopy.

    PubMed

    Warwick, Tony; Chuang, Yi De; Voronov, Dmitriy L; Padmore, Howard A

    2014-07-01

    The optical design of a two-dimensional imaging soft X-ray spectrometer is described. A monochromator will produce a dispersed spectrum in a narrow vertical illuminated stripe (∼2 µm wide by ∼2 mm tall) on a sample. The spectrometer will use inelastically scattered X-rays to image the extended field on the sample in the incident photon energy direction (vertical), resolving the incident photon energy. At the same time it will image and disperse the scattered photons in the orthogonal (horizontal) direction, resolving the scattered photon energy. The principal challenge is to design a system that images from the flat-field illumination of the sample to the flat field of the detector and to achieve sufficiently high spectral resolution. This spectrometer provides a completely parallel resonant inelastic X-ray scattering measurement at high spectral resolution (∼30,000) over the energy bandwidth (∼5 eV) of a soft X-ray absorption resonance.

  1. High resolution measurement of neutron inelastic scattering cross-sections for 23Na

    NASA Astrophysics Data System (ADS)

    Rouki, C.; Archier, P.; Borcea, C.; De Saint Jean, C.; Drohé, J. C.; Kopecky, S.; Moens, A.; Nankov, N.; Negret, A.; Noguère, G.; Plompen, A. J. M.; Stanoiu, M.

    2012-04-01

    The neutron inelastic scattering cross-section of 23Na has been measured in response to the relevant request of the OECD-NEA High Priority Request List, which requires a target uncertainty of 4% in the energy range up to 1.35 MeV for the development of sodium-cooled fast reactors. The measurement was performed at the GELINA facility with the Gamma Array for Inelastic Neutron Scattering (GAINS), featuring eight high purity germanium detectors. The setup is installed at a 200 m flight path from the neutron source and provides high resolution measurements using the (n,n'γ)-technique. The sample was an 80 mm diameter metallic sodium disk prepared at IRMM. Transitions up to the seventh excited state were observed and the differential gamma cross-sections at 110° and 150° were measured, showing mostly isotropic gamma emission. From these the gamma production, level and inelastic cross-sections were determined for neutron energies up to 3838.9 keV. The results agree well with the existing data and the evaluated nuclear data libraries in the low energies, and provide new experimental points in the little studied region above 2 MeV. Following a detailed review of the methodology used for the gamma efficiency calibrations and flux normalization of GAINS data, an estimated total uncertainty of 2.2% was achieved for the inelastic cross-section integrals over the energy ranges 0.498-1.35 MeV and 1.35-2.23 MeV, meeting the required targets.

  2. Laser-assisted inelastic scattering of electrons by helium atoms

    NASA Astrophysics Data System (ADS)

    Agueny, H.; Makhoute, A.; Dubois, A.; Ajana, I.; Rahali, G.

    2015-07-01

    The differential cross section for electron-impact excitation of helium atoms in the presence of a linearly polarized laser field is calculated. The interaction of the laser field with both the projectile electron and the target atom is treated in a fully nonperturbative way, while the electron-atom interaction is treated within the first Born approximation. We are interested in studying two cases where the photon energy of the laser field is chosen to be far from resonance and when it matches with 2 1S ⟶2 1P and 3 1S ⟶3 1P transition frequencies. The agreement between perturbative and nonperturbative results is good, except close to the resonance where the perturbative cross sections diverge while the nonperturbative ones predict no maximum of the cross sections. Another interesting effect is the presence of an avoided crossing of the Floquet pseudoenergies at resonance.

  3. Pygmy dipole resonance in 140Ce via inelastic scattering of 17O

    NASA Astrophysics Data System (ADS)

    Krzysiek, M.; Kmiecik, M.; Maj, A.; Bednarczyk, P.; Bracco, A.; Crespi, F. C. L.; Lanza, E. G.; Litvinova, E.; Paar, N.; Avigo, R.; Bazzacco, D.; Benzoni, G.; Birkenbach, B.; Blasi, N.; Bottoni, S.; Brambilla, S.; Camera, F.; Ceruti, S.; Ciemała, M.; de Angelis, G.; Désesquelles, P.; Eberth, J.; Farnea, E.; Gadea, A.; Giaz, A.; Görgen, A.; Gottardo, A.; Grebosz, J.; Hess, H.; Isocarte, R.; Jungclaus, A.; Leoni, S.; Ljungvall, J.; Lunardi, S.; Mazurek, K.; Menegazzo, R.; Mengoni, D.; Michelagnoli, C.; Milion, B.; Morales, A. I.; Napoli, D. R.; Nicolini, R.; Pellegri, L.; Pullia, A.; Quintana, B.; Recchia, F.; Reiter, P.; Rosso, D.; Salsac, M. D.; Siebeck, B.; Siem, S.; Söderström, P.-A.; Ur, C.; Valiente-Dobon, J. J.; Wieland, O.; Ziebliński, M.

    2016-04-01

    The γ decay from the high-lying states of 140Ce excited via inelastic scattering of 17O at a bombarding energy of 340 MeV was measured using the high-resolution AGATA-demonstrator array in coincidence with scattered ions detected in two segmented Δ E -E silicon detectors. Angular distributions of scattered ions and emitted γ rays were measured, as well as their differential cross sections. The excitation of 1- states below the neutron separation energy is similar to the one obtained in reactions with the α isoscalar probe. The comparison between the experimental differential cross sections and the corresponding predictions using the distorted-wave Born approximation allowed us to extract the isoscalar component of identified 1- pygmy states. For this analysis the form factor obtained by folding microscopically calculated transition densities and optical potentials was used.

  4. Cross-Section Measurements for Elastic and Inelastic Scattering of Neutrons from Noble Gases

    NASA Astrophysics Data System (ADS)

    Macmullin, Sean; Kidd, Mary; Tornow, Werner; Howell, Calvin; Brown, Michael; Henning, Reyco

    2010-11-01

    Neutron backgrounds are a significant concern to experiments that attempt to directly detect Weakly Interacting Massive Particle (WIMP) dark matter. Recoil nuclei produced by neutron elastic scattering can mimic WIMP signatures. There is insufficient experimental data available for the scattering cross-sections of neutrons with noble gases (Ne, Ar, Xe), which are candidate target materials for such experiments. Neutron elastic and inelastic scattering from neon of natural abundance was investigated at the Triangle Universities Nuclear Laboratory at neutron energies relevant to (α,n) and low-energy spallation neutron backgrounds in these experiments. The differential cross-section was measured using a time-of-flight technique at neutron energies of 8.0 and 5.0 MeV. Details of the experimental technique and current status of measurements will be presented.

  5. X-ray induced dimerization of cinnamic acid: Time-resolved inelastic X-ray scattering study

    PubMed Central

    Inkinen, Juho; Niskanen, Johannes; Talka, Tuomas; Sahle, Christoph J.; Müller, Harald; Khriachtchev, Leonid; Hashemi, Javad; Akbari, Ali; Hakala, Mikko; Huotari, Simo

    2015-01-01

    A classic example of solid-state topochemical reactions is the ultraviolet-light induced photodimerization of α-trans-cinnamic acid (CA). Here, we report the first observation of an X-ray-induced dimerization of CA and monitor it in situ using nonresonant inelastic X-ray scattering spectroscopy (NRIXS). The time-evolution of the carbon core-electron excitation spectra shows the effects of two X-ray induced reactions: dimerization on a short time-scale and disintegration on a long time-scale. We used spectrum simulations of CA and its dimerization product, α-truxillic acid (TA), to gain insight into the dimerization effects. From the time-resolved spectra, we extracted component spectra and time-dependent weights corresponding to CA and TA. The results suggest that the X-ray induced dimerization proceeds homogeneously in contrast to the dimerization induced by ultraviolet light. We also utilized the ability of NRIXS for direct tomography with chemical-bond contrast to image the spatial progress of the reactions in the sample crystal. Our work paves the way for other time-resolved studies on chemical reactions using inelastic X-ray scattering. PMID:26568420

  6. X-ray induced dimerization of cinnamic acid: Time-resolved inelastic X-ray scattering study

    NASA Astrophysics Data System (ADS)

    Inkinen, Juho; Niskanen, Johannes; Talka, Tuomas; Sahle, Christoph J.; Müller, Harald; Khriachtchev, Leonid; Hashemi, Javad; Akbari, Ali; Hakala, Mikko; Huotari, Simo

    2015-11-01

    A classic example of solid-state topochemical reactions is the ultraviolet-light induced photodimerization of α-trans-cinnamic acid (CA). Here, we report the first observation of an X-ray-induced dimerization of CA and monitor it in situ using nonresonant inelastic X-ray scattering spectroscopy (NRIXS). The time-evolution of the carbon core-electron excitation spectra shows the effects of two X-ray induced reactions: dimerization on a short time-scale and disintegration on a long time-scale. We used spectrum simulations of CA and its dimerization product, α-truxillic acid (TA), to gain insight into the dimerization effects. From the time-resolved spectra, we extracted component spectra and time-dependent weights corresponding to CA and TA. The results suggest that the X-ray induced dimerization proceeds homogeneously in contrast to the dimerization induced by ultraviolet light. We also utilized the ability of NRIXS for direct tomography with chemical-bond contrast to image the spatial progress of the reactions in the sample crystal. Our work paves the way for other time-resolved studies on chemical reactions using inelastic X-ray scattering.

  7. Monte Carlo Calculation of Thermal Neutron Inelastic Scattering Cross Section Uncertainties by Sampling Perturbed Phonon Spectra

    NASA Astrophysics Data System (ADS)

    Holmes, Jesse Curtis

    Nuclear data libraries provide fundamental reaction information required by nuclear system simulation codes. The inclusion of data covariances in these libraries allows the user to assess uncertainties in system response parameters as a function of uncertainties in the nuclear data. Formats and procedures are currently established for representing covariances for various types of reaction data in ENDF libraries. This covariance data is typically generated utilizing experimental measurements and empirical models, consistent with the method of parent data production. However, ENDF File 7 thermal neutron scattering library data is, by convention, produced theoretically through fundamental scattering physics model calculations. Currently, there is no published covariance data for ENDF File 7 thermal libraries. Furthermore, no accepted methodology exists for quantifying or representing uncertainty information associated with this thermal library data. The quality of thermal neutron inelastic scattering cross section data can be of high importance in reactor analysis and criticality safety applications. These cross sections depend on the material's structure and dynamics. The double-differential scattering law, S(alpha, beta), tabulated in ENDF File 7 libraries contains this information. For crystalline solids, S(alpha, beta) is primarily a function of the material's phonon density of states (DOS). Published ENDF File 7 libraries are commonly produced by calculation and processing codes, such as the LEAPR module of NJOY, which utilize the phonon DOS as the fundamental input for inelastic scattering calculations to directly output an S(alpha, beta) matrix. To determine covariances for the S(alpha, beta) data generated by this process, information about uncertainties in the DOS is required. The phonon DOS may be viewed as a probability density function of atomic vibrational energy states that exist in a material. Probable variation in the shape of this spectrum may be

  8. Neutron Inelastic Scattering Mechanism and Measurement of Neutron Asymmetry Using Time of Flight Technique

    SciTech Connect

    Al Azzawe, A. J. M.

    2007-02-14

    Inelastic scattering is an essential reaction for other nuclear reactions to detect the optical model and compound nucleus formation within the range of (0.4- 5.0) MeV neutron incident energy by using time of flight technique. The time of flight system (TOFS) installed on the horizontal channel reactor RRA has been used to measure the asymmetry of scattered fast neutrons, when data acquisition and system control were recorded event by event by HP - computer via CAMAC system. Eight NE 213 neutron counters were used in order to detect neutron inelastic scattering in the forward direction (4 neutron counters at 0 deg. angle) and in the backward direction (4 neutron counters at 180 deg. angle) to measure the asymmetry of fast neutron. Each neutron counter was 50cm in length and 8cm in diameter, viewed by two (58 - DVP) photomultiplier tubes. The contribution of direct interaction to the compound nucleus formation was deduced from the asymmetry in the neutron detection at the same direction of these eight neutron counters. A time resolution of 8.2 ns between the eight neutron counters and one of the two Ge(Li) detectors has been obtained.

  9. The SEXTANTS beamline at SOLEIL: a new facility for elastic, inelastic and coherent scattering of soft X-rays

    NASA Astrophysics Data System (ADS)

    Sacchi, M.; Jaouen, N.; Popescu, H.; Gaudemer, R.; Tonnerre, J. M.; Chiuzbaian, S. G.; Hague, C. F.; Delmotte, A.; Dubuisson, J. M.; Cauchon, G.; Lagarde, B.; Polack, F.

    2013-03-01

    SEXTANTS is a new SOLEIL beamline dedicated to soft X-ray scattering techniques. The beamline, covering the 50-1700 eV energy range, features two Apple-II undulators for polarization control and a fixed-deviation monochromator. Two branch-lines host three end-stations for elastic, inelastic and coherent scattering experiments.

  10. Deep Inelastic Scattering results from the first year of HERA operation

    SciTech Connect

    Magill, S.R.

    1993-12-31

    The first year of operation of the HERA electron-proton collider has resulted in Deep Inelastic Scattering (DIS) Physics results from both the H1 and ZEUS experiments. Reported here are the H1 and ZEUS measurements of the proton structure function F{sub 2} at higher Q{sup 2} and lower x than previously reported from fixed target experiments. Also included are the results of QCD studies on hadronic final states and jets, and the observation of high Q{sup 2} charged current events from both experiments. Finally, the observation of events with large rapidity gaps by the ZEUS collaboration is also reported.

  11. Jet production in deep-inelastic muon scattering at 490 GeV

    SciTech Connect

    Melanson, H.L.

    1993-06-01

    Measurements of jet rates in deep-inelastic muon scattering are presented. The JADE algorithm is used to define jets in the kinematic region 9 < W < 33 GeV. Data taken on a proton target are analyzed within the QCD framework, with the goal of extracting [alpha][sub s]. Results on the Q[sup 2] dependence of the average transverse momentum of jets are used to demonstrate the running of the strong coupling constant [alpha][sub s]. In addition, first measurements of the production of jets from heavy nuclei in the region x[sub B[sub j

  12. The application of inelastic neutron scattering to investigate the interaction of methyl propanoate with silica.

    PubMed

    McFarlane, Andrew R; Geller, Hannah; Silverwood, Ian P; Cooper, Richard I; Watkin, David J; Parker, Stewart F; Winfield, John M; Lennon, David

    2016-06-29

    A modern industrial route for the manufacture of methyl methacrylate involves the reaction of methyl propanoate and formaldehyde over a silica-supported Cs catalyst. Although the process has been successfully commercialised, little is known about the surface interactions responsible for the forward chemistry. This work concentrates upon the interaction of methyl propanoate over a representative silica. A combination of infrared spectroscopy, inelastic neutron scattering, DFT calculations, X-ray diffraction and temperature-programmed desorption is used to deduce how the ester interacts with the silica surface. PMID:27182815

  13. Inelastic electron scattering in the high-Tc compound YBa2Cu3O7-x

    NASA Astrophysics Data System (ADS)

    Tarrio, C.; Schnatterly, S. E.

    1988-07-01

    We have carried out inelastic electron scattering transmission measurements on the high-Tc compound YBa2Cu3O7-x in the energy range 1-100 eV. We have directly observed the free-electron plasma peak at 1.1 eV in addition to the bound electron plasmon at 25.5 eV. The interband threshold is at 2.1 eV, above which the material behaves as a typical oxide insulator.

  14. A low-temperature sample mount for an inelastic electron scattering spectrometer

    NASA Astrophysics Data System (ADS)

    Tarrio, C.; Schnatterly, S. E.; Benitez, E. L.

    1990-10-01

    A continuously operable low-temperature (10-20 K) sample mount for a solid-state inelastic electron scattering spectrometer is described. The cooling is achieved by a closed-cycle gas phase He refrigerator. Because the entire sample chamber is at a potential of 300 kV, it must be isolated from ground, requiring computer automation for positioning, and insulating plumbing for the helium. The motion control has a detachable coupling that allows for complete thermal isolation from room temperature. Details and problems encountered in the design are described.

  15. Inelastic neutron scattering study of light-induced dynamics of a photosynthetic membrane system

    SciTech Connect

    Furrer, A.; Stoeckli, A.

    2010-01-15

    Inelastic neutron scattering was employed to study photoeffects on the molecular dynamics of membranes of the photosynthetic bacterium Rhodopseudomonas viridis. The main photoactive parts of this biomolecular system are the chlorophyll molecules whose dynamics were found to be affected under illumination by visible light in a twofold manner. First, vibrational modes are excited at energies of 12(2) and 88(21) cm{sup -1}. Second, a partial 'freezing' of rotational modes is observed at energies of 1.2(3) and 2.9(5) cm{sup -1}. These results are attributed to a possible coupling between molecular motions and particular mechanisms in the photosynthetic process.

  16. High-frequency collective excitations in molten and glassy Te studied by inelastic neutron scattering

    SciTech Connect

    Ruiz-Martin, M. D.; Jimenez-Ruiz, M.; Bermejo, F. J.

    2006-03-01

    The spectra of collective excitations of liquid and glassy tellurium have been studied by means of inelastic neutron scattering. Here we report on the dynamics of liquid Te as measured at two different temperatures, just above melting (T{sub m}=723 K) and at {approx}1000 K as well as the glass that is studied at room temperature. Estimates for the velocity of propagating excitations for both temperatures have been obtained from the experimental data, and a contrasting behavior is found with respect to anomalies shown by the adiabatic sound velocity measured by ultrasound methods. The origin of such differences is finally discussed.

  17. Resonant inelastic x-ray scattering studies of the organic semiconductor copper phthalocyanine

    SciTech Connect

    Kodituwakku, C. N.; Burns, C. A.; Said, A. H.; Sinn, H.; Wang, X.; Gog, T.; Casa, D. M.; Tuel, M.; Western Michigan Univ.; DESY, Hasylab

    2008-01-01

    We report resonant inelastic x-ray scattering (RIXS) measurements on polycrystalline and single crystal samples of the organic semiconductor {beta}-copper phthalocyanine (CuPc) as well as time dependent density functional theory calculations of the electronic properties of the CuPc molecule. Resonant and nonresonant excitations were measured along the three crystal axes with 120 meV resolution. We observe molecular excitations as well as charge-transfer excitons along certain crystal directions and compare our data with the calculations. Our results demonstrate that RIXS is a powerful tool for studying excitons and other electronic excitations in organic semiconductors.

  18. Transverse inelastic electron scattering from the deuteron at high momentum transfers

    SciTech Connect

    Bosted, P.E.; Arnold, R.G.; Benton, D.; Clogher, L.; DeChambrier, G.; Katramatou, A.T.; Lambert, J.; Lung, A.; Petratos, G.G.; Rahbar, A.; and others

    1988-11-20

    Cross sections for 180/sup 0/ inelastic electron scattering from the deuteron were measured from the break-up threshold to beyond the quasielastic peak for incident beam energies between 0.7 and 1.3 GeV, corresponding to 0.75less than or equal toQ/sup 2/less than or equal to2.75 (GeV/c)/sup 2/. The data are in reasonable agreement with nonrelativistic models that include final-state interactions are meson exchange currents.

  19. Hydration structures near finite-sized nanoscopic objects reconstructed using inelastic x-ray scattering measurements.

    PubMed

    Coridan, Robert H; Schmidt, Nathan W; Lai, Ghee Hwee; Wong, Gerard C L

    2009-10-21

    Recent work has shown that it is possible to use high resolution dynamical structure factor S(q,ω) data measured with inelastic x-ray scattering to reconstruct the Green's function of water, which describes its dynamical density response to a point charge. Here, we generalize this approach and describe a strategy for reconstructing hydration behavior near simple charge distributions with excluded volumes, with the long term goal of engaging hydration processes in complex molecular systems. We use this Green's function based imaging of dynamics method to generate hydration structures and show that they are consistent with those of well-studied model systems.

  20. Elastic modulus of supercooled liquid and hot solid silicon measured by inelastic X-ray scattering

    SciTech Connect

    Alatas, A.; Said, A. H.; Sinn, H.; Alp, E. E.; Kodituwakku, C. N.; Reinhart, B.; Saboungi, M. -L.; Price, D. L.

    2005-12-01

    We measured the dynamical structure factors of supercooled-liquid and hot-solid silicon by inelastic X-ray scattering at the same temperature, 1620 K. Two significant changes in the averaged longitudinal sound velocities and in the longitudinal modulus are observed. We, first observe a different longitudinal modulus in the polycrystalline hot-solid silicon compared to the extrapolated value obtained from the single-crystal measurement. Furthermore, this reduction of the modulus may be a precursor of the semiconductor-to-metal transition. Second, the increase in the longitudinal modulus in the liquid upon supercooling is consistent with an increase in the degree of the directional bonding.

  1. Spin-Ml and El responses of nuclei probed by proton inelastic scattering

    NASA Astrophysics Data System (ADS)

    Tamii, Atsushi; Matsubara, Hiroaki

    2014-12-01

    We pick up two studies on the nuclear responses from the recent experiments of high-resolution proton inelastic scattering at the Research Center for Nuclear Physics, Osaka University; 1) study of the nuclear symmetry and the neutron skin thickness by the measurement of energy electric dipole (El) response of 208Pb, and 2) study of the tensor correlation in the ground state by the measurement of the spin-Ml responses of even-even self-conjugate nuclei in the sd-shell nuclei.

  2. First measurements of jet production rates in deep-inelastic lepton-proton scattering

    SciTech Connect

    Adams, M.R.; Aied, S.; Anthony, P.L.; Baker, M.D.; Bartlett, J.; Bhatti, A.A.; Braun, H.M.; Busza, W.; Conrad, J.M.; Coutrakon, G.; Davisson, R.; Derado, I.; Dhawan, S.K.; Dougherty, W.; Dreyer, T.; Dziunikowska, K.; Eckardt, V.; Ecker, U.; Erdmann, M.; Eskreys, A.; Figiel, J.; Gebauer, H.J.; Geesaman, D.F.; Gilman, R.; Green, M.C.; Haas, J.; Halliwell, C.; Hanlon, J.; Hantke, D.; Hughes, V.W.; Jackson, H.E.; Jaffe, D.E.; Jancso, G.; Jansen, D.M.; Kaufman, S.; Kennedy, R.D.; Kobrak, H.G.E.; Krzywdzinski, S.; Kunori, S.; Lord, J.J.; Lubatti, H.J.; McLeod, D.; Magill, S.; Malecki, P.; Manz, A.; Michael, D.G.; Mohr, W.; Montgomery, H.E.; Morfin, J.G.; Nickerson, R.B.; O'Day, S.; Olkiewicz, K.; Osborne, L.; Papavassiliou, V.; Pawlik, B.; Pipkin, F.M.; Ramberg, E.J.; Roeser, A.; Ryan, J.; Salgado, C.W.; Salvarani, A.; Schellman, H.; Schmitz, N.; Schueler, K.P.; Seyerlein, H.J.; Skuja, A.; Snow, G.A.; Soeldner-Rembold, S.; Steinberg, P.H.; Stier, H.E.; Stopa, P.; Swanson, R.A.; Talaga, R.; T

    1992-08-17

    The first measurements of forward multijet rates in deep-inelastic lepton scattering are presented. Data were taken with a 490-GeV muon beam incident on a hydrogen target. The jets were defined using the GADE algorithm. The measured rates are presented as a function of the jet resolution parameter {ital y}{sub cut}, and as a function of the virtual-photon--proton center-of-momentum energy {ital W}, in the range 13{le}{ital W}{le}33 GeV. Comparisons are made to the predictions of the Lund Monte Carlo programs and good agreement is obtained when QCD corrections are included in the model.

  3. First measurements of jet production rates in deep-inelastic lepton-proton scattering

    NASA Astrophysics Data System (ADS)

    Adams, M. R.; Aïd, S.; Anthony, P. L.; Baker, M. D.; Bartlett, J.; Bhatti, A. A.; Braun, H. M.; Busza, W.; Conrad, J. M.; Coutrakon, G.; Davisson, R.; Derado, I.; Dhawan, S. K.; Dougherty, W.; Dreyer, T.; Dziunikowska, K.; Eckardt, V.; Ecker, U.; Erdmann, M.; Eskreys, A.; Figiel, J.; Gebauer, H. J.; Geesaman, D. F.; Gilman, R.; Green, M. C.; Haas, J.; Halliwell, C.; Hanlon, J.; Hantke, D.; Hughes, V. W.; Jackson, H. E.; Jaffe, D. E.; Jancso, G.; Jansen, D. M.; Kaufman, S.; Kennedy, R. D.; Kobrak, H. G.; Krzywdzinski, S.; Kunori, S.; Lord, J. J.; Lubatti, H. J.; McLeod, D.; Magill, S.; Malecki, P.; Manz, A.; Michael, D. G.; Mohr, W.; Montgomery, H. E.; Morfin, J. G.; Nickerson, R. B.; O'day, S.; Olkiewicz, K.; Osborne, L.; Papavassiliou, V.; Pawlik, B.; Pipkin, F. M.; Ramberg, E. J.; Röser, A.; Ryan, J.; Salgado, C. W.; Salvarani, A.; Schellman, H.; Schmitz, N.; Schüler, K. P.; Seyerlein, H. J.; Skuja, A.; Snow, G. A.; Söldner-Rembold, S.; Steinberg, P. H.; Stier, H. E.; Stopa, P.; Swanson, R. A.; Talaga, R.; Tentindo-Repond, S.; Trost, H.-J.; Venkataramania, H.; Vidal, M.; Wilhelm, M.; Wilkes, J.; Wilson, Richard; Wittek, W.; Wolbers, S. A.; Zhao, T.

    1992-08-01

    The first measurements of forward multijet rates in deep-inelastic lepton scattering are presented. Data were taken with a 490-GeV muon beam incident on a hydrogen target. The jets were defined using the gade algorithm. The measured rates are presented as a function of the jet resolution parameter ycut, and as a function of the virtual-photon-proton center-of-momentum energy W, in the range 13<=W<=33 GeV. Comparisons are made to the predictions of the Lund Monte Carlo programs and good agreement is obtained when QCD corrections are included in the model.

  4. Energy calibration of a high-resolution inelastic x-ray scattering spectrometer

    SciTech Connect

    Verbeni, Roberto; D'Astuto, Matteo; Krisch, Michael; Lorenzen, Maren; Mermet, Alain; Monaco, Giulio; Requardt, Herwig; Sette, Francesco

    2008-08-15

    The energy scale of a triple-axis x-ray spectrometer with meV energy resolution based on perfect silicon crystal optics is calibrated, utilizing the most recent determination of the silicon lattice parameter and its thermal expansion coefficient and recording the dispersion of longitudinal acoustic and optical phonons in a diamond single crystal and the molecular vibration mode in liquid nitrogen. Comparison of the x-ray results with previous inelastic neutron and Raman scattering results as well as with ab initio phonon dispersion calculations yields an overall agreement better than 2%.

  5. A pressure cell for nonresonant inelastic x-ray scattering studies of gas phases

    SciTech Connect

    Minzer, M.; Bradley, J. A.; Musgrave, R.; Seidler, G. T.; Skilton, A.

    2008-08-15

    We report the design and performance of a gas-phase sample cell for measurements of momentum transfer (q) dependent nonresonant inelastic x-ray scattering (NRIXS). NRIXS measurements from He gas at 2 MPa (20 bars) readily demonstrate dipole-allowed and dipole-forbidden final states for two-electron excitations. Direct comparison of gas-phase NRIXS measurements with the corresponding nonresonant electron energy loss spectroscopy results (EELS) will be a valuable method for characterizing systematic errors in either technique for studies that require absolute normalization of the double differential cross section.

  6. Inelastic X-ray scattering experiments on B[subscript 4]C under high static pressures

    SciTech Connect

    Kumar, Ravhi S.; Dandekar, Dattatraya; Leithe-Jasper, Andres; Tanaka, Takaho; Xiao, Yuming; Chow, Paul; Nicol, Malcolm F.; Cornelius, Andrew L.

    2010-05-04

    Boron K-edge inelastic X-ray scattering experiments were performed on clean B{sub 4}C and shock impact recovered boron carbide up to 30 GPa and at ambient temperature to understand the pressure induced bonding changes. The spectral features corresponding to the boron site in the interlinking chain remained unchanged up to 30 GPa. The results of our experiments indicate that pressure induces less distortion to the boron sites and the local amorphization observed in the previous reports are due to the rearrangement of carbon atoms under extreme conditions without affecting the boron environment.

  7. Novel rhenium gasket design for nuclear resonant inelastic x-ray scattering at high pressure

    SciTech Connect

    Tanis, Elizabeth A.; Giefers, Hubertus; Nicol, Malcolm F.

    2008-02-15

    For the first time, a highly absorbing element, rhenium, has been proven to be a strong, reliable, and safe gasket material for achieving high pressure in nuclear resonant inelastic x-ray scattering (NRIXS) experiments. Rhenium foil was cut into rectangular slices and in order to reduce absorption, the elevated imprint due to preindenting of the gasket is removed using electrical discharge machining. By utilizing this novel gasket design, transmission losses were mitigated while performing NRIXS experiments conducted on the {sup 119}Sn and {sup 57}Fe Moessbauer isotopes.

  8. Measurement of the Parity-Violating Asymmetry in Deep Inelastic Scattering at JLab 6 GeV

    SciTech Connect

    Wang, Diancheng

    2013-12-01

    The parity-violating asymmetry in deep inelastic scattering (PVDIS) offers us a useful tool to study the weak neutral couplings and the hadronic structure of the nucleon, and provides high precision tests on the Standard Model. During the 6 GeV PVDIS experiment at the Thomas Jefferson National Accelerator Facility, the parity-violating asymmetries A{sub PV} of a polarized electron beam scattering off an unpolarized deuteron target in the deep inelastic scattering region were precisely measured at two Q2 values of 1.1 and 1.9 (GeV/c)2. The asymmetry at Q2=1.9 (GeV/c)2 can be used to extract the weak coupling combination 2C2u - C2d, assuming the higher twist effect is small. The extracted result from this measurement is in good agreement with the Standard Model prediction, and improves the precision by a factor of five over previous data. In addition, combining the asymmetries at both Q2 values provides us extra knowledge on the higher twist effects. The parity violation asymmetries in the resonance region were also measured during this experiment. These results are the first APV data in the resonance region beyond the Δ (1232). They provide evidence that the quark hadron duality works for APV at the (10-15)% level, and set constraints on nucleon resonance models that are commonly used for background calculations to other parity-violating electron scattering measurements.

  9. Resonant inelastic light scattering and photoluminescence in isolated nc-Si/SiO{sub 2} quantum dots

    SciTech Connect

    Bairamov, F. B. Toporov, V. V.; Poloskin, E. D.; Bairamov, H.; Roeder, C.; Sprung, C.; Bohmhammel, K.; Seidel, J.; Irmer, G.; Lashkul, A.; Laehderanta, E.; Song, Y. W.

    2013-05-15

    Observation at the room temperature the spectra of the resonant inelastic light scattering by the spatially confined optical phonons as well as the excitonic luminescence caused by confinement effects in the ensemble of isolated quantum dots (QDs) nc-Si/SiO{sub 2} is reported. It is shown that the samples investigated are high purity and high crystalline perfection quality nc-Si/SiO{sub 2} QDs without amorphous phase {alpha}-Si and contaminants. Comparison between the experimental data obtained and phenomenological model of the strong space confinement of optical phonons revealed the need of the more accurate form of the weighted function for the confinement of optical phonons. It is shown that simultaneous detection of the inelastic light scattering by the confinement of phonons and the excitonic luminescence spectra by the confined electron-hole pairs in the nc-Si/SiO{sub 2} QDs allows selfconsistently to determine more accurate values of the diameter of the nc-Si/SiO{sub 2} QDs.

  10. A scaler-based data acquisition system for measuring parity-violating asymmetry in deep inelastic scattering

    NASA Astrophysics Data System (ADS)

    Subedi, R.; Wang, D.; Pan, K.; Deng, X.; Michaels, R.; Reimer, P. E.; Shahinyan, A.; Wojtsekhowski, B.; Zheng, X.

    2013-10-01

    An experiment that measured the parity-violating asymmetries in deep inelastic scattering was completed at the Thomas Jefferson National Accelerator Facility in experimental Hall A. From these asymmetries, a combination of the quark weak axial charge could be extracted with a factor of five improvement in precision over world data. To achieve this, asymmetries at the 10-4 level needed to be measured at event rates up to 600 kHz and the high pion background typical to deep inelastic scattering experiments needed to be rejected efficiently. A specialized data acquisition (DAQ) system with intrinsic particle identification (PID) was successfully developed and used: the pion contamination in the electron samples was controlled at the order of 2×10-4 or below with an electron efficiency of higher than 91% during most of the production period of the experiment, the systematic uncertainty in the measured asymmetry due to DAQ deadtime was below 0.5%, and the statistical quality of the asymmetry measurement agreed with the Gaussian distribution to over five orders of magnitudes. The DAQ system is presented here with an emphasis on its design scheme, the achieved PID performance, deadtime effect and the capability of measuring small asymmetries.

  11. A scaler-based data acquisition system for measuring parity-violating asymmetry in deep inelastic scattering

    SciTech Connect

    Subedi, Ramesh R.; Wang, Diancheng; Pan, Kai; Deng, Xiaoyan; Michaels, Robert W.; Shahinyan, Albert; Wojtsekhowski, Bogdan B.; Zheng, Xiaochao

    2013-10-01

    An experiment that measured the parity violating asymmetries in deep inelastic scattering was completed at the Thomas Jefferson National Accelerator Facility in experimental Hall A. From these asymmetries, a combination of the quark weak axial charge could be extracted with a factor of five improvement in precision over world data. To achieve this, asymmetries at the 10^-4 level needed to be measured at event rates up to 500 kHz and the high pion background typical to deep inelastic scattering experiments needed to be rejected efficiently. A specialized data acquisition (DAQ) system with intrinsic particle identification (PID) was successfully developed and used: The pion contamination in the electron samples was controlled at the order of 2 × 10^-4 or below with an electron efficiency of higher than 91% throughout the production period of the experiment, the systematic uncertainty in the measured asymmetry due to DAQ deadtime was below 0.2%, and the statistical quality of the asymmetry measurement agreed with the Gaussian distribution to over five orders of magnitudes. The DAQ system is presented here with an emphasis on its design scheme, the achieved PID performance, deadtime effect and the capability of measuring small asymmetries.

  12. Distorted spin dependent spectral function of {sup 3}He and semi-inclusive deep inelastic scattering processes

    SciTech Connect

    Kaptari, Leonya P.; Del Dotto, Alessio; Pace, Emanuele; Salme, Giovanni; Scopetta, Sergio

    2014-03-01

    The spin dependent spectral function, relevant to describe polarized electron scattering off polarized {sup 3}He, is studied, within the Plane Wave Impulse Approximation and taking into account final state interaction effects (FSI). In particular, the case of semi-inclusive deep inelastic scattering (SiDIS) is considered, evaluating the FSI of the hadronizing quark with the nuclear remnants. It is shown that particular kinematical regions can be selected to minimize the latter effects, so that parton distributions in the neutron can be accessed. On the other side, in the regions where FSI dominates, the considered reactions can elucidate the mechanism of hadronization of quarks during the propagation in the nuclear medium. It is shown that the obtained spin dependent spectral function can be directly applied to investigate the SiDIS reaction e-vector + {sup 3}He-vector to h+X, where the hadron h originates from the current fragmentation. Experiments of this type are being performed at JLab to extract neutron transverse momentum dependent parton distributions. As a case study, a different SiDIS process, with detection of slow (A-1) systems in the final state, is considered in more details, in order to establish when nuclear structure effects and FSI can be distinguished from elementary reactions on quasi-free nucleons. It is argued that, by a proper choice of kinematics, the origin of nuclear effects in polarized DIS phenomena and the details of the interaction between the hadronizing quark and the nuclear medium can be investigated at a level which is not reachable in inclusive deep inelastic scattering.

  13. Resonances in rotationally inelastic scattering of NH3 and ND3 with H2.

    PubMed

    Ma, Qianli; van der Avoird, Ad; Loreau, Jérôme; Alexander, Millard H; van de Meerakker, Sebastiaan Y T; Dagdigian, Paul J

    2015-07-28

    We present theoretical studies on the scattering resonances in rotationally inelastic collisions of NH3 and ND3 molecules with H2 molecules. We use the quantum close-coupling method to compute state-to-state integral and differential cross sections for the NH3/ND3-H2 system for collision energies between 5 and 70 cm(-1), using a previously reported potential energy surface [Maret et al., Mon. Not. R. Astron. Soc. 399, 425 (2009)]. We identify the resonances as shape or Feshbach resonances. To analyze these, we use an adiabatic bender model, as well as examination at the scattering wave functions and lifetimes. The strength and width of the resonance peaks suggest that they could be observed in a crossed molecular beam experiment involving a Stark-decelerated NH3 beam.

  14. Selectivity in the inelastic rotational scattering of hydrogen molecules from graphite

    NASA Astrophysics Data System (ADS)

    Rutigliano, Maria; Pirani, Fernando

    2016-11-01

    The inelastic scattering of hydrogen molecules in well-defined roto-vibrational states, impinging a graphite surface from sub-thermal up to hyper-thermal collision energies, has been investigated by using a new Potential Energy Surface, formulated in terms of a recently proposed Improved Lennard Jones model, suitable to describe non-covalent interactions in the full space of the configurations. The collision dynamics is studied by a semiclassical method. The focus has been on behaviour of molecules initially in low-medium lying roto-vibrational states, for which, under the assumed conditions, initial vibrational state is in general preserved during the collision. For the rotational relaxation, some selectivities in the final state formation have been characterized. They are emerging especially at low collision energies, where the scattering is manly driven by the attractive forces controlling the physical adsorption. The rotational and vibrational accommodation coefficients have been evaluated and found to be in agreement with those reported in literature.

  15. Band Structure of Helimagnons in MnSi Resolved by Inelastic Neutron Scattering.

    PubMed

    Kugler, M; Brandl, G; Waizner, J; Janoschek, M; Georgii, R; Bauer, A; Seemann, K; Rosch, A; Pfleiderer, C; Böni, P; Garst, M

    2015-08-28

    A magnetic helix realizes a one-dimensional magnetic crystal with a period given by the pitch length λh. Its spin-wave excitations-the helimagnons-experience Bragg scattering off this periodicity, leading to gaps in the spectrum that inhibit their propagation along the pitch direction. Using high-resolution inelastic neutron scattering, the resulting band structure of helimagnons was resolved by preparing a single crystal of MnSi in a single magnetic-helix domain. At least five helimagnon bands could be identified that cover the crossover from flat bands at low energies with helimagnons basically localized along the pitch direction to dispersing bands at higher energies. In the low-energy limit, we find the helimagnon spectrum to be determined by a universal, parameter-free theory. Taking into account corrections to this low-energy theory, quantitative agreement is obtained in the entire energy range studied with the help of a single fitting parameter.

  16. Inelastic x-ray scattering studies on dynamic structure factor of polymeric liquid Se under pressure

    SciTech Connect

    Inui, Masanori; Kajihara, Yukio; Kimura, Koji; Matsuda, Kazuhiro; Ohara, Koji; Tsutsui, Satoshi; Ishikawa, Daisuke

    2015-08-17

    Inelastic X-ray scattering measurements at 25 MPa using synchrotron radiation were carried out for semiconducting liquid Se at high temperatures up to 1673 K. The excitation energy of the acoustic mode disperses approximately 10-50 % faster than the ultrasonic sound velocity in the observed temperature range while the ultrasonic sound rapidly slows down with increasing temperature. We carried out X-ray scattering measurements and found that the average coordination number at 1673 K is 1.3, indicating that the high temperature liquid consists of short chain molecules. These results suggest that weakening of the interatomic interaction is correlated with breaking of polymeric chain molecules.

  17. Ground state potential energy surfaces around selected atoms from resonant inelastic x-ray scattering

    NASA Astrophysics Data System (ADS)

    Schreck, Simon; Pietzsch, Annette; Kennedy, Brian; Såthe, Conny; Miedema, Piter S.; Techert, Simone; Strocov, Vladimir N.; Schmitt, Thorsten; Hennies, Franz; Rubensson, Jan-Erik; Föhlisch, Alexander

    2016-01-01

    Thermally driven chemistry as well as materials’ functionality are determined by the potential energy surface of a systems electronic ground state. This makes the potential energy surface a central and powerful concept in physics, chemistry and materials science. However, direct experimental access to the potential energy surface locally around atomic centers and to its long-range structure are lacking. Here we demonstrate how sub-natural linewidth resonant inelastic soft x-ray scattering at vibrational resolution is utilized to determine ground state potential energy surfaces locally and detect long-range changes of the potentials that are driven by local modifications. We show how the general concept is applicable not only to small isolated molecules such as O2 but also to strongly interacting systems such as the hydrogen bond network in liquid water. The weak perturbation to the potential energy surface through hydrogen bonding is observed as a trend towards softening of the ground state potential around the coordinating atom. The instrumental developments in high resolution resonant inelastic soft x-ray scattering are currently accelerating and will enable broad application of the presented approach. With this multidimensional potential energy surfaces that characterize collective phenomena such as (bio)molecular function or high-temperature superconductivity will become accessible in near future.

  18. Ground state potential energy surfaces around selected atoms from resonant inelastic x-ray scattering

    PubMed Central

    Schreck, Simon; Pietzsch, Annette; Kennedy, Brian; Såthe, Conny; Miedema, Piter S.; Techert, Simone; Strocov, Vladimir N.; Schmitt, Thorsten; Hennies, Franz; Rubensson, Jan-Erik; Föhlisch, Alexander

    2016-01-01

    Thermally driven chemistry as well as materials’ functionality are determined by the potential energy surface of a systems electronic ground state. This makes the potential energy surface a central and powerful concept in physics, chemistry and materials science. However, direct experimental access to the potential energy surface locally around atomic centers and to its long-range structure are lacking. Here we demonstrate how sub-natural linewidth resonant inelastic soft x-ray scattering at vibrational resolution is utilized to determine ground state potential energy surfaces locally and detect long-range changes of the potentials that are driven by local modifications. We show how the general concept is applicable not only to small isolated molecules such as O2 but also to strongly interacting systems such as the hydrogen bond network in liquid water. The weak perturbation to the potential energy surface through hydrogen bonding is observed as a trend towards softening of the ground state potential around the coordinating atom. The instrumental developments in high resolution resonant inelastic soft x-ray scattering are currently accelerating and will enable broad application of the presented approach. With this multidimensional potential energy surfaces that characterize collective phenomena such as (bio)molecular function or high-temperature superconductivity will become accessible in near future. PMID:26821751

  19. Ground state potential energy surfaces around selected atoms from resonant inelastic x-ray scattering.

    PubMed

    Schreck, Simon; Pietzsch, Annette; Kennedy, Brian; Såthe, Conny; Miedema, Piter S; Techert, Simone; Strocov, Vladimir N; Schmitt, Thorsten; Hennies, Franz; Rubensson, Jan-Erik; Föhlisch, Alexander

    2016-01-01

    Thermally driven chemistry as well as materials' functionality are determined by the potential energy surface of a systems electronic ground state. This makes the potential energy surface a central and powerful concept in physics, chemistry and materials science. However, direct experimental access to the potential energy surface locally around atomic centers and to its long-range structure are lacking. Here we demonstrate how sub-natural linewidth resonant inelastic soft x-ray scattering at vibrational resolution is utilized to determine ground state potential energy surfaces locally and detect long-range changes of the potentials that are driven by local modifications. We show how the general concept is applicable not only to small isolated molecules such as O2 but also to strongly interacting systems such as the hydrogen bond network in liquid water. The weak perturbation to the potential energy surface through hydrogen bonding is observed as a trend towards softening of the ground state potential around the coordinating atom. The instrumental developments in high resolution resonant inelastic soft x-ray scattering are currently accelerating and will enable broad application of the presented approach. With this multidimensional potential energy surfaces that characterize collective phenomena such as (bio)molecular function or high-temperature superconductivity will become accessible in near future.

  20. Crystal Dynamics of (delta) fcc Pu-Ga by High Resolution Inelastic X-Ray Scattering

    SciTech Connect

    Wong, J; Krisch, M; Farber, D; Occelli, F; Xu, R; Chiang, T C; Clatterbuck, D; Schwartz, A J; Wall, M; Boro, C

    2004-09-28

    We have used a microbeam on large grain sample concept to carry out an inelastic x-ray scattering experiment to map the full phonon dispersion curves of an fcc {delta}-phase Pu-Ga alloy. This approach obviates experimental difficulties with conventional inelastic neutron scattering due to the high absorption cross section of the common {sup 239}Pu isotope and the non-availability of large (mm size) single crystal materials for Pu and its alloys. A classical Born von-Karman force constant model was used to model the experimental results, and no less than 4th nearest neighbor interactions had to be included to account for the observation. Several unusual features including, a large elastic anisotropy, a small shear elastic modulus, (C{sub 11}-C{sub 12})/2, a Kohn-like anomaly in the T{sub 1}[011] branch, and a pronounced softening of the T[111] branch towards the L point in the Brillouin are found. These features can be related to the phase transitions of plutonium and to strong coupling between the crystal structure and the 5f valence instabilities. Our results represent the first full phonon dispersions ever obtained for any Pu-bearing material, thus ending a 40-year quest for this fundamental data. The phonon data also provide a critical test for theoretical treatments of highly correlated 5f electron systems as exemplified by recent dynamical mean field theory (DMFT) calculations for {delta}-plutonium.

  1. Multiferroic phase of doped delafossite CuFeO2 identified using inelastic neutron scattering

    SciTech Connect

    Haraldsen, Jason T; Ye, Feng; Fishman, Randy Scott; Fernandez-Baca, Jaime A; Yamaguchi, Y.; Kimura, K.; Kimura, T.

    2010-01-01

    Multiferroic materials allow the electric polarization to be controlled by switching the direction of magnetic ordering and consequently offer prospects for many new technological applications [1 4]. Because multiferroic behavior has been found in materials that exhibit complex (non-collinear and incommensurate) magnetic order, it is essential to know the spin arrangement of the ground states in these materials [4 9]. In many cases, elastic neutron scattering measurements alone are not sufficient to distinguish among several potential complex magnetic states. We report inelastic neutron scattering (INS) measurements that provide a distinct dynamical fingerprint for the multiferroic ground state of 3.5% Ga-doped CuFeO2. The complex ground state is stabilized by the displacement of the oxygen atoms [10], which are also responsible for the multiferroic coupling predicted by Arima [8]. By comparing the observed and calculated spectrum of spin excitations, we conclude that the magnetic ground state is a distorted screwtype spin configuration. The exchange interactions that stabilize this structure are consistent with those obtained from inelastic measurements [11, 12] on undoped CuFeO2.

  2. Inelastic scattering of OH radicals from organic liquids: isolating the thermal desorption channel.

    PubMed

    King, Kerry L; Paterson, Grant; Rossi, Giovanni E; Iljina, Marija; Westacott, Robin E; Costen, Matthew L; McKendrick, Kenneth G

    2013-08-21

    Inelastic scattering of OH radicals from liquid surfaces has been investigated experimentally. An initially translationally and rotationally hot distribution of OH was generated by 193 nm photolysis of allyl alcohol. These radicals were scattered from an inert reference liquid, perfluorinated polyether (PFPE), and from the potentially reactive hydrocarbon liquids squalane (C30H62, 2,6,10,15,19,23-hexamethyltetracosane) and squalene (C30H50, trans-2,6,10,15,19,23-hexamethyltetracosa-2,6,10,14,18,22-hexaene). The scattered OH v = 0 products were detected by laser-induced fluorescence. Strong correlations were observed between the translational and rotational energies of the products. The high-N levels are translationally hot, consistent with a predominantly direct, impulsive scattering mechanism. Impulsive scattering also populates the lower-N levels, but a component of translationally relaxed OH, with thermal-desorption characteristics, can also be seen clearly for all three liquids. More of this translationally and rotationally relaxed OH survives from squalane than from squalene. Realistic molecular dynamics simulations confirm that double-bond sites are accessible at the squalene surface. This supports the proposition that relaxed OH may be lost on squalene via an addition mechanism.

  3. Understanding inelastically scattered neutrons from water on a time-of-flight small-angle neutron scattering (SANS) instrument

    NASA Astrophysics Data System (ADS)

    Do, Changwoo; Heller, William T.; Stanley, Christopher; Gallmeier, Franz X.; Doucet, Mathieu; Smith, Gregory S.

    2014-02-01

    It is generally assumed by most of the small-angle neutron scattering (SANS) user community that a neutron's energy is unchanged during SANS measurements. Here, the scattering from water, specifically light water, was measured on the EQ-SANS instrument, a time-of-flight (TOF) SANS instrument located at the Spallation Neutron Source of Oak Ridge National Laboratory. A significant inelastic process was observed in the TOF spectra of neutrons scattered from water. Analysis of the TOF spectra from the sample showed that the scattered neutrons have energies consistent with room-temperature thermal energies (~20 meV) regardless of the incident neutron's energy. With the aid of Monte Carlo particle transport simulations, we conclude that the thermalization process within the sample results in faster neutrons that arrive at the detector earlier than expected based on the incident neutron energies. This thermalization process impacts the measured SANS intensities in a manner that will ultimately be sample- and temperature-dependent, necessitating careful processing of the raw data into the SANS cross-section.

  4. Coulomb Corrections in Deep Inelastic Scattering and the Nuclear Dependence of R =σL /σT

    NASA Astrophysics Data System (ADS)

    Gaskell, David

    2011-04-01

    Measurements of Deep Inelastic structure functions from nuclei are typically performed at very high energies, hence effects from the Coulombic acceleration or deceleration of the incident and scattered lepton due to additional protons in a heavy nucleus are typically ignored. However, re-analysis of data taken at SLAC from experiments E140 and E139 indicates that the effect of including Coulomb corrections, while not large, is non-zero and impacts the extracted results non-trivially. In particular, there is a significant impact when these data are used to extrapolate the magnitude of the EMC effect to nuclear matter. In addition, the conclusion from E140 that there is no evidence for a nuclear dependence of R =σL /σT is thrown into question. When combined with recent data from Jefferson Lab, RA -RD at x = 0 . 5 is found to differ from zero by two σ.

  5. Elastic and inelastic neutron scattering cross sections for fission reactor applications

    NASA Astrophysics Data System (ADS)

    Hicks, S. F.; Chakraborty, A.; Combs, B.; Crider, B. P.; Downes, L.; Girgis, J.; Kersting, L. J.; Kumar, A.; Lueck, C. J.; McDonough, P. J.; McEllistrem, M. T.; Peters, E. E.; Prados-Estevz, F. M.; Schniederjan, J.; Sidwell, L.; Sigillito, A. J.; Vanhoy, J. R.; Watts, D.; Yates, S. W.

    2013-04-01

    Nuclear data important for the design and development of the next generation of light-water reactors and future fast reactors include neutron elastic and inelastic scattering cross sections on important structural materials, such as Fe, and on coolant materials, such as Na. These reaction probabilities are needed since neutron reactions impact fuel performance during irradiations and the overall efficiency of reactors. While neutron scattering cross sections from these materials are available for certain incident neutron energies, the fast neutron region, particularly above 2 MeV, has large gaps for which no measurements exist, or the existing uncertainties are large. Measurements have been made at the University of Kentucky Accelerator Laboratory to measure neutron scattering cross sections on both Fe and Na in the region where these gaps occur and to reduce the uncertainties on scattering from the ground state and first excited state of these nuclei. Results from measurements on Fe at incident neutron energies between 2 and 4 MeV will be presented and comparisons will be made to model calculations available from data evaluators.

  6. Rotationally inelastic scattering of methyl radicals with Ar and N{sub 2}

    SciTech Connect

    Tkáč, Ondřej; Orr-Ewing, Andrew J.; Ma, Qianli; Dagdigian, Paul J.; Stei, Martin

    2015-01-07

    The rotationally inelastic scattering of methyl radical with Ar and N{sub 2} is examined at collision energies of 330 ± 25 cm{sup −1} and 425 ± 50 cm{sup −1}, respectively. Differential cross sections (DCSs) were measured for different final n′ rotational levels (up to n′ = 5) of the methyl radicals, averaged over k′ sub-levels, using a crossed molecular beam machine with velocity map imaging. For Ar as a collision partner, we present a newly constructed ab initio potential energy surface and quantum mechanical scattering calculations of state-resolved DCSs. These computed DCSs agree well with the measurements. The DCSs for both Ar and N{sub 2} collision partners are strongly forward peaked for all spectroscopic lines measured. For scattering angles below 60°, the theoretical CD{sub 3}–Ar DCSs show diffraction oscillations that become less pronounced as n′ increases, but these oscillations are not resolved experimentally. Comparisons are drawn with our recently reported DCSs for scattering of methyl radicals with He atoms.

  7. Stokes-anti-Stokes correlation in the inelastic scattering of light by matter and generalization of the Bose-Einstein population function

    NASA Astrophysics Data System (ADS)

    Parra-Murillo, Carlos A.; Santos, Marcelo F.; Monken, Carlos H.; Jorio, Ado

    2016-03-01

    The Stokes and anti-Stokes components in the inelastic scattering of light are related to phonon statistics and have been broadly used to measure temperature and phonon lifetimes in different materials. However, correlation between the components is expected to change the Stokes/anti-Stokes intensity ratio, imposing corrections to the broadly used Bose-Einstein statistics. In this work the excitation power dependence of these scattering processes is theoretically described by an effective Hamiltonian that includes correlation between the Stokes and the anti-Stokes events. The model is used to fit available experimental results in three-dimensional diamond and two-dimensional graphene, showing that the phenomenon can significantly increase in the low-dimensional system under specific resonance conditions. By setting the scientific basis for the Stokes-anti-Stokes correlated phenomenon, the use of the Bose-Einstein population function to determine the inelastic scattering is generalized, providing a model to predict the conversion of optical phonons into heat or light, according to coupling constants and decay rates. The model applies to inelastic scattering in general.

  8. The simultaneous measurement of energy and linear polarization of the scattered radiation in resonant inelastic soft x-ray scattering

    SciTech Connect

    Braicovich, L. Minola, M.; Dellea, G.; Ghiringhelli, G.; Le Tacon, M.; Moretti Sala, M.; Morawe, C.; Peffen, J.-Ch.; Yakhou, F.; Brookes, N. B.; Supruangnet, R.

    2014-11-15

    Resonant Inelastic X-ray Scattering (RIXS) in the soft x-ray range is an element-specific energy-loss spectroscopy used to probe the electronic and magnetic excitations in strongly correlated solids. In the recent years, RIXS has been progressing very quickly in terms of energy resolution and understanding of the experimental results, but the interpretation of spectra could further improve, sometimes decisively, from a full knowledge of the polarization of incident and scattered photons. Here we present the first implementation, in a high resolution soft-RIXS spectrometer used to analyze the scattered radiation, of a device allowing the measurement of the degree of linear polarization. The system, based on a graded W/B{sub 4}C multilayer mirror installed in proximity of the CCD detector, has been installed on the AXES spectrometer at the ESRF (European Synchrotron Radiation Facility); it has been fully characterized and it has been used for a demonstration experiment at the Cu L{sub 3} edge on a high-T{sub c} superconducting cuprate. The loss in efficiency suffered by the spectrometer equipped with this test facility was a factor 17.5. We propose also a more advanced version, suitable for a routine use on the next generation of RIXS spectrometers and with an overall efficiency up to 10%.

  9. Polarized Electron - Polarized Deuteron Deep-Inelastic Scattering in Electron-Ion Collider with Tagging

    NASA Astrophysics Data System (ADS)

    Sargsian, Misak; Cosyn, Wim; Weiss, Christian

    2015-10-01

    For the past several years there have been an intensive research and development for the possible electron-ion collider that will be able to probe deep inelastic processes at unprecedentedly high energies in eA channel. One of the important advantages of the collider kinematics in DIS processes is the possibility for an unambiguous separation of hadrons emerging from DIS and hadrons fragmenting from the target nucleus. This creates a unique possibility for tagging the interacting nucleon with the recoil slow fragments in the DIS process. The situation is most clean for the deuteron target in which case the recoil particle is a nucleon. In addition, the possibility of having polarized deuteron beams will create unprecedented opportunities in probing polarization degrees of freedom for parton distributions in the interacting bound nucleon. In this work we develop a theoretical framework for the polarized electron-polarized deuteron deep inelastic scattering in which the recoil nucleon is detected in the target fragmentation region. Two main contributions for which theoretical models are developed are the plane-wave impulse approximation, in which no reinteractions are taking place between the final state products of DIS and the recoil nucleon.

  10. Differential and integral cross sections for the rotationally inelastic scattering of methyl radicals with H2 and D2

    NASA Astrophysics Data System (ADS)

    Tkáč, Ondřej; Ma, Qianli; Rusher, Cassandra A.; Greaves, Stuart J.; Orr-Ewing, Andrew J.; Dagdigian, Paul J.

    2014-05-01

    Comparisons are presented of experimental and theoretical studies of the rotationally inelastic scattering of CD3 radicals with H2 and D2 collision partners at respective collision energies of 680 ± 75 and 640 ± 60 cm-1. Close-coupling quantum-mechanical calculations performed using a newly constructed ab initio potential energy surface (PES) provide initial-to-final CD3 rotational level (n, k → n', k') integral and differential cross sections (ICSs and DCSs). The DCSs are compared with crossed molecular beam and velocity map imaging measurements of angular scattering distributions, which serve as a critical test of the accuracy of the new PES. In general, there is very good agreement between the experimental measurements and the calculations. The DCSs for CD3 scattering from both H2 and D2 peak in the forward hemisphere for n' = 2-4 and shift more to sideways and backward scattering for n' = 5. For n' = 6-8, the DCSs are dominated by backward scattering. DCSs for a particular CD3 n → n' transition have a similar angular dependence with either D2 or H2 as collision partner. Any differences between DCSs or ICSs can be attributed to mass effects because the PES is unchanged for CD3-H2 and CD3-D2 collisions. Further comparisons are drawn between the CD3-D2 scattering and results for CD3-He presented in our recent paper [O. Tkáč, A. G. Sage, S. J. Greaves, A. J. Orr-Ewing, P. J. Dagdigian, Q. Ma, and M. H. Alexander, Chem. Sci. 4, 4199 (2013)]. These systems have the same reduced mass, but are governed by different PESs.

  11. Evolution of thermodynamic properties and inelastic neutron scattering intensities for spin-1/2 antiferromagnetic quantum rings

    NASA Astrophysics Data System (ADS)

    Haraldsen, Jason T.

    2016-08-01

    This study examines the increasing complexity in the magnetic properties of small n =3 ,4 ,5 ,and 6 spin-1/2 quantum rings. Using an exact diagonalization of the isotropic Heisenberg Hamiltonian with nearest and next-nearest neighbor interactions, the energy eigenstates, magnetic specific heat capacity, magnetic susceptibility, and inelastic neutron scattering structure factors are determined for variable next-nearest neighbor interactions. Here, it is shown that the presence of spin exchange symmetry breaking, multiple ground states, and nonzero total spin ground states can greatly complicate the energy eigenstates and excitations for these systems. Overall, the energy eigenstates and structure factor intensities are presented in closed form, while the thermodynamic properties detail the effect of a crossing interaction in the rings. The goal of this work is to provide insight into the evolution of the magnetic properties and spin excitations within these systems.

  12. Nuclear resonant inelastic X-ray scattering at high pressure and low temperature

    DOE PAGESBeta

    Bi, Wenli; Zhao, Jiyong; Lin, Jung -Fu; Jia, Quanjie; Hu, Michael Y.; Jin, Changqing; Ferry, Richard; Yang, Wenge; Struzhkin, Viktor; Alp, E. Ercan

    2015-01-01

    In this study, a new synchrotron radiation experimental capability of coupling nuclear resonant inelastic X-ray scattering with the cryogenically cooled high-pressure diamond anvil cell technique is presented. The new technique permits measurements of phonon density of states at low temperature and high pressure simultaneously, and can be applied to studies of phonon contribution to pressure- and temperature-induced magnetic, superconducting and metal–insulator transitions in resonant isotope-bearing materials. In this report, a pnictide sample, EuFe2As2, is used as an example to demonstrate this new capability at beamline 3-ID of the Advanced Photon Source, Argonne National Laboratory. A detailed description of the technicalmore » development is given. The Fe-specific phonon density of states and magnetism from the Fe sublattice in Eu57Fe2As2 at high pressure and low temperature were derived by using this new capability.« less

  13. Study of mixed-symmetry excitations in 96Ru via inelastic proton-scattering

    NASA Astrophysics Data System (ADS)

    Hennig, A.; Spieker, M.; Werner, V.; Ahn, T.; Anagnostatou, V.; Cooper, N.; Derya, V.; Elvers, M.; Endres, J.; Goddard, P.; Heinz, A.; Hughes, R. O.; Ilie, G.; Mineva, M. N.; Pickstone, S. G.; Petkov, P.; Radeck, D.; Ross, T.; Savran, D.; Zilges, A.

    2015-02-01

    Mixed-symmetry states of octupole (L = 3) and hexadecapole (L = 4) character have been recently proposed in the N = 52 isotones 92 Zr and 94Mo, based on strong M1 transitions to the lowest-lying 3- and 4+ states, respectively. In order to investigate similar excitations in the heaviest stable N = 52 isotone 96Ru, two inelastic proton-scattering experiments have been performed at the Wright Nuclear Structure Laboratory (WNSL), Yale University, USA and the Institute for Nuclear Physics, University of Cologne, Germany. From the combined data of both experiments, absolute E1, M1, and E2 transition strengths were extracted, allowing for the identification of candidates for MS octupole and hexadecapole states. The structure of the low-lying 4+ states is investigated by means of sdg-IBM-2 calculations.

  14. Beam spin asymmetries from semi-inclusive pion electroproduction in deep inelastic scattering

    SciTech Connect

    Gohn, W.; Joo, K.; Ungaro, M.; Avakian, H.

    2009-08-04

    Measurements of beam-spin asymmetries from semi-inclusive pion electro-production in deep inelastic scattering (DIS) have been performed. Data were taken with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab using a 5.7 GeV longitudinally polarized electron beam and an unpolarized liquid hydrogen target. All three pion channels ({pi}{sup +}, {pi}{sup 0} and {pi}{sup -}) were measured simultaneously over a large range of kinematics at the intermediate Q{sup 2} range (Q{sup 2}{approx_equal}1-3 GeV{sup 2}). We present our preliminary studies of single-spin azimuthal asymmetries of the two charged pion channels as functions of z and P{sub T}. This new high statistical data will provide important means of studying physics underlying the spin structure of the nucleon.

  15. Jet production in deep-inelastic muon scattering at 490 GeV

    SciTech Connect

    Melanson, H.L.; E665 Collaboration

    1993-06-01

    Measurements of jet rates in deep-inelastic muon scattering are presented. The JADE algorithm is used to define jets in the kinematic region 9 < W < 33 GeV. Data taken on a proton target are analyzed within the QCD framework, with the goal of extracting {alpha}{sub s}. Results on the Q{sup 2} dependence of the average transverse momentum of jets are used to demonstrate the running of the strong coupling constant {alpha}{sub s}. In addition, first measurements of the production of jets from heavy nuclei in the region x{sub B{sub j}} > 0.001 are discussed. Initial results indicate a suppression in the rate of two forward jets in carbon, calcium and lead as compared to deuterium. All results presented are preliminary.

  16. Multi-jet production rates in deep-inelastic muon-proton scattering

    SciTech Connect

    Salgado, C.W.

    1992-10-01

    Measurements of forward multi-jet production rates in deep-inelastic muonproton scattering are presented. Data were taken with a 490 GeV muon beam incident on a hydrogen target. Jets were defined using the JADE jet finding algorithm. The measured rates are presented as function of W, the hadronic center-of-mass energy and the jet resolution parameter, y[sub cut], in energies up to W=33 GeV. Good agreement is found in comparisons with predictions of the QCD-inspired Lund Monte Carlo models. Non-perturbative QCD production mechanisms, inside the Lund Model, can not reproduce the results for energies greater than W [approx equal] 20 GeV. Sensitivities of the jet rate measurements to the low x (x [approx equal] 0.02) gluon content of the nucleon and the evolution of [alpha][sub s], are studied.

  17. Multi-jet production rates in deep-inelastic muon-proton scattering

    SciTech Connect

    Salgado, C.W.; E665 Collaboration

    1992-10-01

    Measurements of forward multi-jet production rates in deep-inelastic muonproton scattering are presented. Data were taken with a 490 GeV muon beam incident on a hydrogen target. Jets were defined using the JADE jet finding algorithm. The measured rates are presented as function of W, the hadronic center-of-mass energy and the jet resolution parameter, y{sub cut}, in energies up to W=33 GeV. Good agreement is found in comparisons with predictions of the QCD-inspired Lund Monte Carlo models. Non-perturbative QCD production mechanisms, inside the Lund Model, can not reproduce the results for energies greater than W {approx_equal} 20 GeV. Sensitivities of the jet rate measurements to the low x (x {approx_equal} 0.02) gluon content of the nucleon and the evolution of {alpha}{sub s}, are studied.

  18. Study of the microdynamics of liquid lithium and lithium-hydrogen melt by inelastic neutron scattering

    SciTech Connect

    Blagoveshchenskii, N. M.; Morozov, V. A.; Novikov, A. G.; Pashnev, M. A. Savostin, V. V.; Shimkevich, A. L.

    2007-05-15

    The frequency spectra of vibrations of Li atoms at temperatures of 22, 227, 397, and 557 deg. C and the lithium-hydrogen melt (98 at % {sup 7}Li, 2 at % H) at 557 deg. C have been obtained from the experimental neutron inelastic scattering data. On the basis of the frequency spectra, the temperature dependences of the mean-square displacement of Li atoms, the mean-square amplitudes of atomic vibrations, and the velocity autocorrelation function of atoms have been calculated. The speed of sound in liquid lithium has been estimated within the Debye model. The frequency spectra of lithium-hydrogen melt and solid lithium hydride are compared. A generalized frequency spectrum of vibrations of hydrogen atoms in lithium-hydrogen melt is obtained.

  19. Implications of resonant inelastic x-ray scattering data for theoretical models of cuprates

    NASA Astrophysics Data System (ADS)

    Chen, Wei; Sushkov, Oleg P.

    2013-11-01

    There are two commonly discussed points of view in theoretical description of cuprate superconductors: (i) Cuprates can be described by the modified t-J model; (ii) overdoped cuprates are close to the regime of normal Fermi liquid (NFL). We argue that recent resonant inelastic x-ray scattering data challenge both points. While the modified t-J model describes well the strongly underdoped regime, it fails to describe high energy magnetic excitations when approaching optimal doping. This probably indicates failure of the Zhang-Rice singlet picture. In the overdoped regime the momentum-integrated spin structure factor S(ω) has the same intensity and energy distribution as that in an undoped parent compound. This implies that the entire spin spectral sum rule is saturated at ω≈2J, while in an NFL the spectral weight should saturate only at the total bandwidth which is much larger than 2J.

  20. Nitric oxide heme interactions in nitrophorin 7 investigated by nuclear inelastic scattering

    NASA Astrophysics Data System (ADS)

    Auerbach, H.; Faus, I.; Rackwitz, S.; Wolny, J. A.; Walker, F. A.; Chumakov, A. I.; Ogata, H.; Knipp, M.; Schünemann, V.

    2014-04-01

    Nitrophorins (NPs) occur in the blood-sucking insect Rhodnius prolixus. These proteins use ferric heme to store nitric oxide (NO) in the salivary glands of the insects and transport it to the victim's tissues, resulting in vasodilation and reduced blood coagulation. In this work we present a nuclear inelastic scattering (NIS) study in order to characterize the iron-NO interaction in the isoform nitrophorin 7 (NP7). The NIS data obtained for NP7 complexed with NO show a strong band at ˜589 cm-1 which is due to modes with significant Fe-NO stretching and bending character. Another conspicuous feature is a significant peak at ˜280 cm-1 in the region where the heme modes occur. Based on a hybrid calculation method, which uses density functional theory and molecular mechanics, the band at ˜280 cm-1 is assigned to heme modes with substantial doming character.

  1. General Helicity Formalism for Polarized Semi-Inclusive Deep Inelastic Scattering

    SciTech Connect

    Anselmino, M; Boglione, M; D’Alesio, U; Melis, S; Murgia, F; Nocera, E R; Prokudin, A

    2011-06-01

    We study polarized Semi-Inclusive Deep Inelastic Scattering (SIDIS) processes, within the QCD parton model and a factorization scheme, taking into account all transverse motions, of partons inside the initial proton and of hadrons inside the fragmenting partons. We use the helicity formalism. The elementary interactions are computed at LO with non collinear exact kinematics, which introduces phases in the expressions of their helicity amplitudes. Several Transverse Momentum Dependent (TMD) distribution and fragmentation functions appear and contribute to the cross sections and to spin asymmetries. Our results agree with those obtained with different formalisms, showing the consistency of our approach. The full expression for single and double spin asymmetries is derived. Simplified, explicit analytical expressions, convenient for phenomenological studies, are obtained assuming a factorized Gaussian dependence on intrinsic momenta for the TMDs.

  2. Inelastic neutron scattering spectra of alkali metal (Na, K) bifluorides: The harmonic overtone of v3

    NASA Astrophysics Data System (ADS)

    Waddington, Thomas C.; Howard, Joseph; Brierley (in part), Keith P.; Tomkinson, John

    1982-01-01

    Inelastic neutron scattering spectra of MFHF (M  Na and K) have been measured up to energy transfers of ca. 4000 cm -1 Both 0 → 1 and 0 → 2 transitions of the bending ( v2), and antisymmetric stretching ( v3) modes were observed. A normal harmonic (i.e. no quartic contribution) model for the dynamics of the bifluoride ion is entirely consistent with our observations. Evidence of phonon dispersion was observed in the band shape of v3, but no structure attributable to the LO mode could be found. The similarity of the band shapes of v3 for both NaFHF and KFHF is interpreted in terms of a very short range coupling mechanism.

  3. The inelastic neutron scattering spectrum of chromous acid at high energy transfers

    NASA Astrophysics Data System (ADS)

    Tomkinson, J.; Taylor, A. D.; Howard, J.; Eckert, J.; Goldstone, J. A.

    1985-02-01

    The inelastic incoherent neutron scattering spectrum of chromous acid, at 77 K, is presented. It is dominated by the intense bending mode at 1254 cm-1 with some modes at lower frequencies showing indications of dispersion. The antisymmetric stretch νas(OHS) {‖1>-‖2>} was assigned to a broad band centered at ˜2050 cm-1, significantly displaced for the IR assignment (1650 cm-1). The breadth of the band is due to the dispersion, and kinematic coupling, that is anticipated for this compound. These new data allows us to fit chromous acid more clearly into the general trend of hydrogen bonded compounds. Chromous acid compares very well in its overall INS spectrum with the isomorphous sodium bifluoride, except that the kinematic coupling between νas(OHO) and the symmetric stretch does not occur in this compound.

  4. Inelastic x-ray scattering measurements of phonon dynamics in URu2Si2

    DOE PAGESBeta

    Gardner, D. R.; Bonnoit, C. J.; Chisnell, R.; Said, A. H.; Leu, B. M.; Williams, Travis J.; Luke, G. M.; Lee, Y. S.

    2016-02-11

    In this paper, we study high-resolution inelastic x-ray scattering measurements of the acoustic phonons of URu2Si2. At all temperatures, the longitudinal acoustic phonon linewidths are anomalously broad at small wave vectors revealing a previously unknown anharmonicity. The phonon modes do not change significantly upon cooling into the hidden order phase. In addition, our data suggest that the increase in thermal conductivity in the hidden order phase cannot be driven by a change in phonon dispersions or lifetimes. Hence, the phonon contribution to the thermal conductivity is likely much less significant compared to that of the magnetic excitations in the lowmore » temperature phase.« less

  5. Inelastic neutron scattering study of water in hydrated LTA-type zeolites.

    PubMed

    Corsaro, Carmelo; Crupi, Vincenza; Majolino, Domenico; Parker, Stewart F; Venuti, Valentina; Wanderlingh, Ulderico

    2006-01-26

    The vibrational dynamics of water molecules encapsulated in synthetic Na-A and Mg-exchanged A zeolites were studied versus temperature by inelastic neutron scattering (INS) measurements (30-1200 cm(-1)) as a function of the induced ion-exchange percentage by using the indirect geometry tof spectrometer TOSCA at the ISIS pulse neutron facility (RAL, UK). The experimental INS spectra were compared with those of ice Ih to characterize the structural changes induced by confinement on the H2O hydrogen-bonded network. We observed, after increasing the Mg2+ content, a tendency of water molecules to restore the bulklike arrangements together with more hindered dynamics. These results are confirmed by the analysis of the evaluated one-phonon amplitude-weighted proton vibrational density of states aimed, in particular, to follow the evolution of the water molecules librational mode region.

  6. Cold-collision-shift cancellation and inelastic scattering in a Yb optical lattice clock

    SciTech Connect

    Ludlow, A. D.; Lemke, N. D.; Sherman, J. A.; Oates, C. W.; Quemener, G.; Stecher, J. von; Rey, A. M.

    2011-11-15

    Recently, p-wave cold collisions were shown to dominate the density-dependent shift of the clock transition frequency in a {sup 171}Yb optical lattice clock. Here we demonstrate that by operating such a system at the proper excitation fraction, the cold-collision shift is canceled below the 5x10{sup -18} fractional frequency level. We report inelastic two-body loss rates for {sup 3} P{sub 0} -{sup 3} P{sub 0} and {sup 1} S{sub 0} -{sup 3} P{sub 0} scattering. We also measure interaction shifts in an unpolarized atomic sample. Collision measurements for this spin-1/2 {sup 171}Yb system are relevant for high-performance optical clocks as well as strongly interacting systems for quantum information and quantum simulation applications.

  7. Quasi elastic and inelastic neutron scattering study of vitamin C aqueous solutions

    NASA Astrophysics Data System (ADS)

    Migliardo, F.; Branca, C.; Magazù, S.; Migliardo, P.; Coppolino, S.; Villari, A.; Micali, N.

    2002-02-01

    In this paper, new results obtained by quasi elastic and inelastic neutron scattering experiments performed on vitamin C ( L-ascorbic acid)/H 2O mixtures are reported. The data analysis of the QENS measurements, by a separation of the diffusive dynamics of hydrated L-ascorbic acid from that of water, furnishes quantitative evidences of a random jump diffusion motion of vitamin C and shows that the water dynamics is strongly affected by the presence of L-ascorbic acid. Concerning the INS experiment, we are able, through the behaviour of neutron spectra across the glass transition temperature ( T g≈233 K for the vitamin C/water system), to collocate the investigated system in the Angell “strong-fragile” scheme.

  8. Neutron Inelastic Scattering Measurements for Na, Ge, Zr, Mo and U

    NASA Astrophysics Data System (ADS)

    Bacquias, A.; Dessagne, Ph.; Kerveno, M.; Rudolf, G.; Plompen, A. J. M.; Drohé, J. C.; Rouki, C.; Nankov, N.; Nyman, M.; Borcea, C.; Negret, A.; Archier, P.; De Saint Jean, C.; Noguère, G.; Vaglio-Gaudard, C.; Koning, A.; Domula, A.; Zuber, K.; Leal, L. C.

    2014-05-01

    Studies for advanced reactor systems such as sodium-cooled fast reactors designed for recycling of high level waste, accelerator driven systems for transmutation, and systems envisioning the use of the Th/U fuel cycle impose tight requirements on nuclear data for accurate predictions of their operation and safety characteristics. Among the identified needs established by sensitivity studies, neutron inelastic scattering on the main structural materials and actinides and some (n,xn) cross sections for actinides feature prominently. Prompt-gamma spectroscopy and time-of-flight techniques were used to measure (n,xnγ) cross-sections of interest. Experiments were performed at the GELINA neutron time-of-flight facility of IRMM. Results for 235U and 23Na are briefly recalled; pertaining theoretical discussions are mentioned to explain observations concerning 238U. The status of studies on 76Ge, Zr and Mo is also reported.

  9. Kohn anomaly in MgB2 by inelastic X-ray scattering.

    PubMed

    Baron, A Q R; Uchiyama, H; Tanaka, Y; Tsutsui, S; Ishikawa, D; Lee, S; Heid, R; Bohnen, K-P; Tajima, S; Ishikawa, T

    2004-05-14

    We study phonons in MgB2 using inelastic x-ray scattering (1.6 and 6 meV resolution). We clearly observe the softening and broadening of the crucial E(2g) mode through the Kohn anomaly along GammaM, in excellent agreement with ab initio calculations. Low temperature measurements (just above and below T(c)) show negligible changes for the momentum transfers investigated and no change in the E(2g) mode at A between room temperature and 16 K. We report the presence of a longitudinal mode along GammaA near in energy to the E(2g) mode that is not predicted by theory.

  10. Refined model of the {Fe9} magnetic molecule from low-temperature inelastic neutron scattering studies

    SciTech Connect

    Engelhardt, Larry; Demmel, Franz; Luban, Marshall; Timco, Grigore A; Tuna, Floriana; Winpenny, Richard E

    2014-06-01

    We present a refined model of the {Fe9} tridiminished icosahedron magnetic molecule system. This molecule was originally modeled as being composed of two ({Fe3} and {Fe6}) clusters, with the Fe3+ ions within each cluster being coupled via exchange interactions, but with no coupling between the clusters. The present inelastic neutron scattering (INS) measurements were used to probe the low-lying energy spectrum of {Fe9}, and these results demonstrate that the previously published model of two uncoupled clusters is incomplete. To achieve agreement between the experiment and theory, we have augmented the model with relatively small exchange coupling between the clusters. A combination of Lanczos matrix diagonalization and quantum Monte Carlo simulations have been used to achieve good agreement between the experimental data and the improved model of the full {Fe9} system despite the complexity of this model (with Hilbert space dimension >107).

  11. Longitudinal polarization of hyperon and antihyperon in semi-inclusive deep-inelastic scattering

    SciTech Connect

    Zhou Shanshan; Chen Ye; Liang Zuotang; Xu Qinghua

    2009-05-01

    We make a detailed study of the longitudinal polarization of hyperons and antihyperons in semi-inclusive deep-inelastic lepton-nucleon scattering. We present the numerical results for spin transfer in quark fragmentation processes, and analyze the possible origins for a difference between the polarization for hyperon and that for the corresponding antihyperon. We present the results obtained in the case that there is no asymmetry between sea and antisea distribution in the nucleon as well as those obtained when such an asymmetry is taken into account. We compare the results with the available data such as those from COMPASS and make predictions for future experiments including those at even higher energies such as at eRHIC.

  12. Sivers asymmetries for inclusive pion and kaon production in deep-inelastic scattering

    SciTech Connect

    Ellis, John; Hwang, Dae Sung; Kotzinian, Aram

    2009-10-01

    We calculate the Sivers distribution functions induced by the final-state interaction due to one-gluon exchange in diquark models of a nucleon structure, treating the cases of scalar and axial-vector diquarks with both dipole and Gaussian form factors. We use these distribution functions to calculate the Sivers single-spin asymmetries for inclusive pion and kaon production in deep-inelastic scattering. We compare our calculations with the results of HERMES and COMPASS, finding good agreement for {pi}{sup +} production at HERMES, and qualitative agreement for {pi}{sup 0} and K{sup +} production. Our predictions for pion and kaon production at COMPASS could be probed with increased statistics. The successful comparison of our calculations with the HERMES data constitutes prima facie evidence that the quarks in the nucleon have some orbital angular momentum in the infinite-momentum frame.

  13. Undergraduate research using γ-ray spectroscopy following inelastic neutron scattering

    NASA Astrophysics Data System (ADS)

    Hicks, Sally F.; Vanhoy, J. R.

    2007-08-01

    Undergraduate students at the University of Dallas (UD) have played a significant role in the investigations of the low-lying collective nuclear excitations observed in the Z = 52 isotopes. These studies were undertaken using γ-ray spectroscopy following inelastic neutron scattering at the University of Kentucky Low-Energy Nuclear Accelerator Facility. Of particular importance in these investigations is the ability to measure γ-ray Doppler shifts in order to extract lifetimes of excited levels ranging from a few fs to 1 ps. UD students have been actively involved in all aspects of the research from operation of the modified CN Van de Graaff accelerator to comparisons of experimental results with model calculations. An overview of undergraduate involvement in this research will be presented, as well as the most recent results of their investigations.

  14. Anomalous vibrational modes in acetanilide: A F. D. S. incoherent inelastic neutron scattering study

    SciTech Connect

    Barthes, M.; Moret, J. ); Eckert, J.; Johnson, S.W.; Swanson, B.I.; Unkefer, C.J. )

    1991-01-01

    The origin of the anomalous infra-red and Raman modes in acetanilide (C{sub 6}H{sub 5}NHCOCH{sub 3}, or ACN), remains a subject of considerable controversy. One family of theoretical models involves Davydov-like solitons nonlinear vibrational coupling, or polaronic'' localized modes. An alternative interpretation of the extra-bands in terms of a Fermi resonance was proposed and recently the existence of slightly non-degenerate hydrogen atom configurations in the H-bond was suggested as an explanation for the anomalies. In this paper we report some new results on the anomalous vibrational modes in ACN that were obtained by inelastic incoherent neutron scattering (INS).

  15. Performance of spherically focusing Ge(444) backscattering analyzers for inelastic x-ray scattering

    SciTech Connect

    Macrander, A.T.; Kushnir, V.I.; Blasdell, R.C. )

    1995-02-01

    A spectrometer designed for use as an undulator source and having targeted resolutions of 0.01 eV in one mode of use and 0.2 eV in another will operate at the APS. We report here on analyzers that we have constructed for use on this spectrometer for 0.2 eV resolution. We have tested them at NSLS beamline X21 using focused wiggler radiation and at the Cornell high energy synchrotron source (CHESS) using radiation from the CHESS-ANL undulator. Analyzers were constructed by gluing and pressing 90-mm-diam, (111) oriented Ge wafers into concave glass forms having a radius near 1 m. An overall inelastic scattering resolution of 0.3 eV using the (444) reflection was demonstrated at CHESS. Recent results at X21 revealed a useful diameter of 74 mm at an 87[degree] Bragg angle.

  16. Performance of spherically focusing Ge(444) backscattering analyzers for inelastic x-ray scattering

    SciTech Connect

    Macrander, A.T.; Kushnir, V.I.; Blasdell, R.C.

    1994-08-01

    A spectrometer designed to use an undulator source and having targeted resolutions of 0.01 eV in one mode of use and 0.2 eV in another will operate at the APS. We report here on analyzers that we have, constructed for use on this spectrometer for 0.2-eV resolution. We have tested them at NSLS beamline X21 using focused wiggler radiation and at CHESS using radiation from the CHESS-ANL undulator. Analyzers were constructed by gluing and pressing 90-mm-diameter, (111) oriented Ge wafers into concave glass forms having a radius near 1 m. An overall inelastic scattering resolution of 0.3 eV using the (444) reflection was demonstrated at CHESS. Recent results at X21 revealed a useful diameter of 74 mm at an 870 Bragg angle.

  17. Inelastic neutron scatter iron concentrations of the moon from orbital gamma ray data

    NASA Technical Reports Server (NTRS)

    Davis, P. A., Jr.; Bielefeld, M. J.

    1981-01-01

    The considered investigation is concerned with the relation between KREEP and thermal neutron flux depression. The Fe(n, n-prime gamma) concentrations of selected lunar regions were calculated by energy-band analysis of the 0.803-0.872 MeV band. The result of the investigation will be used to evaluate the reliability of the previously determined Fe(n, gamma) values. A 0.803-0.872 MeV band was isolated from the Apollo 15 and 16 orbital gamma ray spectra. Preliminary regression analysis of regional ground truth count rates and Fe concentrations showed this energy interval to be optimum for the 0.8467 MeV inelastic scatter (n, n-prime gamma)Fe peak.

  18. Acoustic phonons in chrysotile asbestos probed by high-resolution inelastic x-ray scattering

    SciTech Connect

    Mamontov, Eugene; Vakhrushev, S. B.; Kumzerov, Yu. A,; Alatas, A.

    2009-01-01

    Acoustic phonons in an individual, oriented fiber of chrysotile asbestos (chemical formula Mg{sub 3}Si{sub 2}O{sub 5}(OH){sub 4}) were observed at room temperature in the inelastic x-ray measurement with a very high (meV) resolution. The x-ray scattering vector was aligned along [1 0 0] direction of the reciprocal lattice, nearly parallel to the long axis of the fiber. The latter coincides with [1 0 0] direction of the direct lattice and the axes of the nano-channels. The data were analyzed using a damped harmonic oscillator model. Analysis of the phonon dispersion in the first Brillouin zone yielded the longitudinal sound velocity of (9200 {+-} 600) m/s.

  19. Diffusive and inelastic scattering in ballistic-electron-emission spectroscopy and ballistic-electron-emission microscopy

    SciTech Connect

    Lee, E.Y.; Turner, B.R.; Schowalter, L.J.

    1993-07-01

    Ballistic-electron-emission microscopy (BEEM) of Au/Si(001) n type was done to study whether elastic scattering in the Au overlayer is dominant. It was found that there is no dependence of the BEEM current on the relative gradient of the Au surface with respect to the Si interface, and this demonstrates that significant elastic scattering must occur in the Au overlayer. Ballistic-electron-emission spectroscopy (BEES) was also done, and, rather than using the conventional direct-current BEES, alternating-current (ac) BEES was done on Au/Si and also on Au/PtSi/Si(001) n type. The technique of ac BEES was found to give linear threshold for the Schottky barrier, and it also clearly showed the onset of electron-hole pair creation and other inelastic scattering events. The study of device quality PtSi in Au/PtSi/Si(001) yielded an attenuation length of 4 nm for electrons of energy 1 eV above the PtSi Fermi energy. 20 refs., 5 figs.

  20. Spin Currents Carried by Spinons in XXZ Spin Chains: Signatures in Polarized Inelastic Neutron Scattering

    NASA Astrophysics Data System (ADS)

    English, Leonard Patrick; Braun, Hans-Benjamin; Kulda, Jiri

    2015-03-01

    Quantum spin chains serve as a paradigm for exploring truly quantum phenomena, with spinons being the elementary excitations. Motivated by compounds such as CsCoBr3 and CsCoCl3, we focus on the Ising-like antiferromagnetic Heisenberg XXZ model (spin-1/2). Here we present theoretical results for the total inelastic scattering cross section of spin-polarized neutrons in the presence of an external magnetic field, which is applied transverse to the Ising direction. In particular, we identify the spin current associated with spinons and their corresponding signatures in the neutron scattering cross section. The presence of a transverse magnetic field no longer allows for reliance on Stotz as a conserved quantity, which has traditionally been assumed in this context. As a striking consequence, we find that the spinons carry a non-vanishing spin current, even in the limit of infinitesimal fields. Our results are shown to be in good agreement with experimental neutron scattering data on CsCoBr3.

  1. In situ determination of soil carbon pool by inelastic neutron scattering: Comparison with dry combustion

    SciTech Connect

    Wielopolski, L.; Mitra, S.; Chatterjee, A.; Lal, R.

    2011-01-01

    There is a well-documented need for new in situ technologies for elemental analysis of soil, particularly for carbon (C), that overcome the limitations of the currently established chemical method by dry combustion (DC). In this work, we evaluated the concordance between the new INS (inelastic neutron scattering) technology and the DC method. The comparisons were carried out in the high C content (30-40%) organic soils of Willard, Ohio (4 sites), in natural forest in Willard, Ohio (1 site), and in a watershed pasture, with an {approx} 10{sup o} slope, in Coshocton, Ohio (5 sites). In addition to these stationary measurements, the organic soil and the pasture were continuously scanned with the inelastic neutron scattering (INS) system to obtain the transects mean C value. Both types of measurements, INS and DC, registered a decline in the surface density of C along transects in the watershed and in the organic soil. Similarly, both recorded a drop in C in the organic soil of about 0.16%. In the pastureland, declines in C levels of 0.08% and 0.10% were observed, respectively, by DC and INS. Combining the results from the three sites yielded a very satisfactory correlation between the INS- and DC-responses, with a regression coefficient, r{sup 2}, value of about 0.99. This suggests the possibility of establishing a universal regression line for various soil types. In addition, we demonstrated the ability of INS to measure the mean value over transect. In organic soil the mean value of an INS scan agreed, {approx} 0.5%, with the mean values of the DC analysis, whereas large discrepancy between these two was recorded in the pastureland. Overall, the various trends observed in C measurements by INS concurred with those determined by the DC method, so enhancing the confidence in the new INS technology.

  2. Jet rates from deep inelastic muon scattering in the W range of 15 to 35 GeV

    SciTech Connect

    Salgado, C.

    1991-08-01

    Production rates of forward jets in deep inelastic muon scattering are studied using the JADE jet finding algorithm. The evolution of di-jet rates with W is compared to QCD first order predictions in the W range of 15 to 25 GeV. 7 refs., 3 figs.

  3. Unpolarised TMD Distribution and Fragmentation Functions from recent HERMES and COMPASS Semi-inclusive Deep Inelastic Scattering Multiplicities

    SciTech Connect

    Prokudin, Alexey; Anselmino, Mauro; Boglione, Mariaelena; Melis, Stefano; Gonzalez, J. O.

    2014-10-01

    The unpolarised transverse momentum dependent distribution and fragmentation functions (TMDs) are extracted from HERMES and COMPASS experimental measurements of semi- inclusive deep inelastic scattering multiplicities for charged hadron production. A simple factorised functional form of the TMDs is adopted, with a Gaussian dependence on the intrinsic transverse momentum, which turns out to be quite adequate in shape.

  4. Study of M1 and E1 excitations by high-resolution proton inelastic scattering measurement at forward angles

    SciTech Connect

    Tamii, A.; Adachi, T.; Hatanaka, K.; Hashimoto, H.; Kaneda, T.; Matsubara, H.; Okamura, H.; Sakemi, Y.; Shimizu, Y.; Tameshige, Y.; Yosoi, M.; Carter, J.; Dozono, M.; Fujita, H.; Fujita, Y.; Itoh, M.; Kawabata, T.; Nakanishi, K.; Sasamoto, Y.; Neumann-Cosel, P. von

    2007-06-13

    Experimental technique for measuring proton inelastic scattering with high-resolution at 295 MeV and at forward angles including zero degrees is described. The method is useful for extracting spin part of the M1 strength via nuclear excitation as well as E1 strength via Coulomb excitation. An excitation energy resolution of 20 keV, good scattering angle resolution, and low background condition have been achieved. The experimental technique was applied for several sd and pf shell nuclei.

  5. Low energy excitations in iridates studied with Resonant Inelastic X-ray Scattering

    NASA Astrophysics Data System (ADS)

    Liu, Xuerong

    2013-03-01

    In the iridium oxides, the strong spin-orbit coupling (SOC) of the 5d iridium electrons entangles the orbital and spin degrees of freedom, providing opportunities for exotic magnetic states with highly anisotropic exchange interactions. At the same time, the spatially extended 5d electrons are expected to have much stronger hybridization with the oxygen 2p orbitals, comparing with that in 3d transition element compounds. Both factors make crystal symmetry and local environment crucial in determining the electronic and magnetic properties of the iridates. We present here our resonant inelastic X-ray scattering (RIXS) studies of a number of octahedrally coordinated iridates with special structures, exploring these effects. In particular, for the 1-D spin 1/2 chain compound, Sr3CuIrO6, the wavefunction of the hole in the t2g manifold was reconstructed based on the RIXS spectra. Our results show that it is significantly modified from the isotropic shape expected for Jeff = 1 / 2 states in the strong SOC limit, due to the distortion of the oxygen octahedral cage. This distortion is comparable to, or smaller than, that present in most iridates and thus this work emphasizes the importance of local symmetry for the iridate families. Further, the magnetic excitations of this material were also measured. A large gap of ~30 meV, was found, comparable to the magnetic dispersion bandwidth. This is in contrast to the gapless dispersion expected for linear chain with isotropic Heisenberg exchange interaction. We also studied Na4Ir3O8 which has a hyperkagome lattice, and is a candidate quantum spin liquid. Here, a low energy continuum is observed below the d-d excitations. Optical conductivity measurements performed on the same sample and polarization dependence of the RIXS signal suggest that these excitations are magnetic in origin, agreeing with the spin-liquid state prediction. The work at Brookhaven was supported by the U.S. Department of Energy, Division of Materials Science

  6. Vibrational dynamics in dendridic oligoarylamines by Raman spectroscopy and incoherent inelastic neutron scattering.

    PubMed

    Kulszewicz-Bajer, Irena; Louarn, Guy; Djurado, David; Skorka, Lukasz; Szymanski, Marek; Mevellec, Jean Yves; Rols, Stephane; Pron, Adam

    2014-05-15

    Vibrational dynamics in triarylamine dendrimers was studied in a complementary way by Raman and infrared (IR) spectroscopies and incoherent inelastic neutron scattering (IINS). Three molecules were investigated, namely, unsubstituted triarylamine dendrimer of the first generation and two dendrimers of the first and second generation, substituted in the crown with butyl groups. To facilitate the assignment of the observed IR and Raman modes as well as the IINS peaks, vibrational models, based on the general valence force field method (GVFF), were calculated for all three compounds studied. A perfect consistency between the calculated and experimental results was found. Moreover, an important complementarity of the vibrational spectroscopies and IINS was established for the investigated dendrimers. The IINS peaks originating mainly from the C-H motions were not restricted by particular selection rules and only dependent on the IINS cross section. To the contrary, Raman and IR bands were imposed by the selection rules and the local geometry of the dendrimers yielding mainly C-C and C-N deformation modes with those of C-H nature of much lower intensity. Raman spectroscopy was also applied to the studies of the oxidation of dendrimers to their cationic forms. A strong Raman resonance effect was observed, since the spectra of the studied compounds, registered at different levels of their oxidation, strongly depended on the position of the excitation line with respect to their electronic spectrum. In particular, the blue (458 nm) excitation line turned out to be insensitive toward the cationic forms yielding very limited spectral information. To the contrary, the use of the red (647 nm) and infrared (1064 nm) excitation lines allowed for an unambiguous monitoring of the spectral changes in dendrimers oxidized to nominally monocationic and tricationic states. The analysis of oxidation-induced spectral changes in the tricationic state indicated that the charge storage

  7. Rotationally inelastic scattering of ND3 with H2 as a probe of the intermolecular potential energy surface

    NASA Astrophysics Data System (ADS)

    Tkáč, Ondřej; Saha, Ashim K.; Loreau, Jérôme; Ma, Qianli; Dagdigian, Paul J.; Parker, David H.; van der Avoird, Ad; Orr-Ewing, Andrew J.

    2015-12-01

    Differential cross sections (DCSs) are reported for rotationally inelastic scattering of ND3 with H2, measured using a crossed molecular beam apparatus with velocity map imaging (VMI). ND3 molecules were quantum-state selected in the ground electronic and vibrational levels and, optionally, in the j±k = 11- rotation-inversion level prior to collisions. Inelastic scattering of state-selected ND3 with H2 was measured at the mean collision energy of 580 cm-1 by resonance-enhanced multiphoton ionisation spectroscopy and VMI of ND3 in selected single final j'±k' levels. Comparison of experimental DCSs with close-coupling quantum-mechanical scattering calculations serves as a test of a recently reported ab initio potential energy surface. Calculated integral cross sections reveal the propensities for scattering into various final j'±k' levels of ND3 and differences between scattering by ortho and para H2. Integral and differential cross sections are also computed at a mean collision energy of 430 cm-1 and compared to our recent results for inelastic scattering of state-selected ND3 with He.

  8. Dynamics of H2 adsorbed in porous materials as revealed by computational analysis of inelastic neutron scattering spectra.

    PubMed

    Pham, Tony; Forrest, Katherine A; Space, Brian; Eckert, Juergen

    2016-06-29

    The inelastic scattering of neutrons from adsorbed H2 is an effective and highly sensitive method for obtaining molecular level information on the type and nature of H2 binding sites in porous materials. While these inelastic neutron scattering (INS) spectra of the hindered rotational and translational excitations on the adsorbed H2 contain a significant amount of information, much of this can only be reliably extracted by means of a detailed analysis of the spectra through the utilization of models and theoretical calculations. For instance, the rotational tunneling transitions observed in the INS spectra can be related to a value for the barrier to rotation for the adsorbed H2 with the use of a simple phenomenological model. Since such an analysis is dependent on the model, it is far more desirable to use theoretical methods to compute a potential energy surface (PES), from which the rotational barriers for H2 adsorbed at a particular site can be determined. Rotational energy levels and transitions for the hindered rotor can be obtained by quantum dynamics calculations and compared directly with experiment with an accuracy subject only to the quality of the theoretical PES. In this paper, we review some of the quantum and classical mechanical calculations that have been performed on H2 adsorbed in various porous materials, such as clathrate hydrates, zeolites, and metal-organic frameworks (MOFs). The principal aims of these calculations have been the interpretation of the INS spectra for adsorbed H2 along with the extraction of atomic level details of its interaction with the host. We describe calculations of the PES used for two-dimensional quantum rotation as well as rigorous five-dimensional quantum coupled translation-rotation dynamics, and demonstrate that the combination of INS measurements and computational modeling can provide important and detailed insights into the molecular mechanism of H2 adsorption in porous materials. PMID:27160665

  9. Dynamics of H2 adsorbed in porous materials as revealed by computational analysis of inelastic neutron scattering spectra.

    PubMed

    Pham, Tony; Forrest, Katherine A; Space, Brian; Eckert, Juergen

    2016-06-29

    The inelastic scattering of neutrons from adsorbed H2 is an effective and highly sensitive method for obtaining molecular level information on the type and nature of H2 binding sites in porous materials. While these inelastic neutron scattering (INS) spectra of the hindered rotational and translational excitations on the adsorbed H2 contain a significant amount of information, much of this can only be reliably extracted by means of a detailed analysis of the spectra through the utilization of models and theoretical calculations. For instance, the rotational tunneling transitions observed in the INS spectra can be related to a value for the barrier to rotation for the adsorbed H2 with the use of a simple phenomenological model. Since such an analysis is dependent on the model, it is far more desirable to use theoretical methods to compute a potential energy surface (PES), from which the rotational barriers for H2 adsorbed at a particular site can be determined. Rotational energy levels and transitions for the hindered rotor can be obtained by quantum dynamics calculations and compared directly with experiment with an accuracy subject only to the quality of the theoretical PES. In this paper, we review some of the quantum and classical mechanical calculations that have been performed on H2 adsorbed in various porous materials, such as clathrate hydrates, zeolites, and metal-organic frameworks (MOFs). The principal aims of these calculations have been the interpretation of the INS spectra for adsorbed H2 along with the extraction of atomic level details of its interaction with the host. We describe calculations of the PES used for two-dimensional quantum rotation as well as rigorous five-dimensional quantum coupled translation-rotation dynamics, and demonstrate that the combination of INS measurements and computational modeling can provide important and detailed insights into the molecular mechanism of H2 adsorption in porous materials.

  10. Inelastic electron scattering in amorphous silicon nitride and aluminum oxide with multiple-scattering corrections

    NASA Astrophysics Data System (ADS)

    Livins, Peteris; Aton, T.; Schnatterly, S. E.

    1988-09-01

    Electron-energy-loss measurements for an amorphous chemical-vapor-deposited silicon nitride film and evaporated sapphire in the broad energy range 1-200 eV are investigated. A method, not requiring the zero-loss peak, to remove the multiple scattering is discussed, applied, and the optical constants obtained. An Elliot-type model used with aluminum oxide gives a valence-exciton binding energy of 1.36+/-0.2 eV with a band gap of 9.8+/-0.2 eV. The unexpected strength of the nitrogen 2s transition is noted in silicon nitride.

  11. Differential cross-sections for elastic and inelastic electron scattering from fundamental polyatomic molecules

    NASA Astrophysics Data System (ADS)

    Khakoo, Murtadha A.

    2011-10-01

    The near-threshold scattering of electrons from polyatomic molecules of fundamental interest, e.g. water, primary alcohols and ring molecules e.g. furan, benzene are important in plasma fuel processes, plasmas used in biological processes e.g. in the treatment of skin diseases, astrophysical plasmas, etc. The determination of cross-sections for such molecules has gathered impetus because of the increasing number of applications industrial plasma and biomedical processes and the need to understand and model these complex processes. It is now possible to determine accurate differential cross-sections for electron scattering from these polyatomic molecules. We will present recent normalized, absolute low energy electron scattering differential cross-sections for near-threshold elastic and inelastic scattering from water, primary alcohols, furan and benzene using a well-tested electron spectrometer apparatus. We will also compare our results with those of other experiments and available theoretical models, which show an encouragingly overall improved picture in terms of agreement between the different research groups. Funded by the National Science Foundation Research in an Undergraduate Institution Grant #s 0653452 and 1135203. This work was done collaboratively with Drs. V. Mckoy and C. Winstead, Caltech, USA (National Science Foundation Grant # 0653396 and Office of Basic Energy Sciences, US DOE Grant) and Dr. M. C. A. Lopes, U. Fed. de Juiz de Fora, Minas Gerais, Brazil; Dr. M. H. F. Bettega, U. Fed. do Parana, Curitiba, Brazil Drs. R. F. da Costa and M. A. P. Lima, Universidade Estadual de Campinas UNICAMP and CTBE, Campinas, Brazil (CNPq, FAPESP, FAPEMG, Finep, CENAPAD-SP and CAPES grants). Funded by US-NSF Grant #s 0653452 and 1135203.

  12. A combined analysis of SLAC experiments on deep inelastic e-p and e-d scattering

    SciTech Connect

    Whitlow, L.W.; Bodek, A.; deBarbaro, P.; Dasu, S.; Harada, H.; Krasny, M.W.; Lang, K.; Riordan, E.M.; Rock, S.; Arnold, R.; Benton, D.; Bosted, P.; Button-Shafer, J.; deChambrier, G.; Clogher, L.; Lung, A.; Szalata, Z.M.; Alster, J.; Debebe, B.; Hicks, R.; Dietrich, F.; Van Bibber, K.; Filippone, B.; Jourdan, J.; Milner, R.; McKeown, R.; Potterveld, D.; Walker, R.C.; Gearhart, R.; Para, A.

    1989-08-01

    We report recent work on the extraction of R = {sigma}{sub L}/{sigma}{sub T} and the structure function F{sub 2} over a large kinematic range, which is based on a reanalysis of deep inelastic {var_epsilon} {minus} p and {var_epsilon} {minus} d scattering cross sections measured at SLAC between 1970 and 1985. All these data were corrected for radiative effects using improved versions of external and internal radiative correction procedures. The data from seven individual experiments were normalized to those from the recent high-precision SLAC experiment E140. We find that R{sub p} = R{sub d}, as expected in QCD. The value of R is higher than predicted by QCD even when target-mass effects are included. This difference indicates that additional dynamical higher-twist effects may be present. The structure functions F{sub 2}p and F{sub 2}d were also extracted from the full data sets of normalized cross sections using an empirical fit to R. These structure functions were then compared with data from the CERN muon scattering experiments BCDMS and EMC. We find that our data are consistent with the EMC data, if the latter are multiplied by a normalization factor of 1.07. No single, uniform normalization factor can be applied to the BCDMS data that will bring them into agreement with the SLAC data in the region of overlap.

  13. A combined analysis of SLAC experiments on deep inelastic e-p and e-d scattering

    SciTech Connect

    Whitlow, L.W. ); Bodek, A.; deBarbaro, P.; Dasu, S.; Harada, H.; Krasny, M.W.; Lang, K.; Riordan, E.M. ); Rock, S.; Arnold, R.; Benton, D.; Bosted, P.; Button-Shafer, J.; deChambrier, G.; Clogher, L.; Lung, A.; Szalata, Z.M. ); Alster, J. ); Debebe, B.; Hicks, R. (Massach

    1989-08-01

    We report recent work on the extraction of R = {sigma}{sub L}/{sigma}{sub T} and the structure function F{sub 2} over a large kinematic range, which is based on a reanalysis of deep inelastic {var epsilon} {minus} p and {var epsilon} {minus} d scattering cross sections measured at SLAC between 1970 and 1985. All these data were corrected for radiative effects using improved versions of external and internal radiative correction procedures. The data from seven individual experiments were normalized to those from the recent high-precision SLAC experiment E140. We find that R{sub p} = R{sub d}, as expected in QCD. The value of R is higher than predicted by QCD even when target-mass effects are included. This difference indicates that additional dynamical higher-twist effects may be present. The structure functions F{sub 2}p and F{sub 2}d were also extracted from the full data sets of normalized cross sections using an empirical fit to R. These structure functions were then compared with data from the CERN muon scattering experiments BCDMS and EMC. We find that our data are consistent with the EMC data, if the latter are multiplied by a normalization factor of 1.07. No single, uniform normalization factor can be applied to the BCDMS data that will bring them into agreement with the SLAC data in the region of overlap.

  14. Inelastic electron and Raman scattering from the collective excitations in quantum wires: Zero magnetic field

    NASA Astrophysics Data System (ADS)

    Kushwaha, Manvir S.

    2013-04-01

    The nanofabrication technology has taught us that an m-dimensional confining potential imposed upon an n-dimensional electron gas paves the way to a quasi-(n-m)-dimensional electron gas, with m ⩽ n and 1 ⩽ n, m ⩽ 3. This is the road to the (semiconducting) quasi-n dimensional electron gas systems we have been happily traversing on now for almost two decades. Achieving quasi-one dimensional electron gas (Q-1DEG) [or quantum wire(s) for more practical purposes] led us to some mixed moments in this journey: while the reduced phase space for the scattering led us believe in the route to the faster electron devices, the proximity to the 1D systems left us in the dilemma of describing it as a Fermi liquid or as a Luttinger liquid. No one had ever suspected the potential of the former, but it took quite a while for some to convince the others on the latter. A realistic Q-1DEG system at the low temperatures is best describable as a Fermi liquid rather than as a Luttinger liquid. In the language of condensed matter physics, a critical scrutiny of Q-1DEG systems has provided us with a host of exotic (electronic, optical, and transport) phenomena unseen in their higher- or lower-dimensional counterparts. This has motivated us to undertake a systematic investigation of the inelastic electron scattering (IES) and the inelastic light scattering (ILS) from the elementary electronic excitations in quantum wires. We begin with the Kubo's correlation functions to derive the generalized dielectric function, the inverse dielectric function, and the Dyson equation for the dynamic screened potential in the framework of Bohm-Pines' random-phase approximation. These fundamental tools then lead us to develop methodically the theory of IES and ILS for the Q-1DEG systems. As an application of the general formal results, which know no bounds regarding the subband occupancy, we compute the density of states, the Fermi energy, the full excitation spectrum [comprised of intrasubband and

  15. Inelastic electron and Raman scattering from the collective excitations in quantum wires

    NASA Astrophysics Data System (ADS)

    Kushwaha, Manvir

    2014-03-01

    The nanofabrication technology has taught us that an m-dimensional confining potential imposed upon an n-dimensional electron gas paves the way to a quasi-(n- m)-dimensional electron gas, with m <= n and 1 <= n , m <= 3 . This is the road to the (semiconducting) quasi- n dimensional electron gas systems we have been happily traversing on now for almost two decades. Achieving quasi-one dimensional electron gas (Q-1DEG) led us to some mixed moments in this journey: while the reduced phase space for the scattering led us believe in the route to the faster electron devices, the proximity to the 1D systems left us in the dilemma of describing it as a Fermi liquid or as a Luttinger liquid. No one had ever suspected the potential of the former, but it took quite a while for some to convince the others on the latter. A realistic Q-1DEG system at the low temperatures is best describable as a Fermi liquid rather than as a Luttinger liquid. This has motivated us to employ the Bohm-Pines' full RPA to develop a systematic methodology for the inelastic electron and light scattering from the collective (plasmon) excitations in Q-1DEG [or quantum wires]. We will discuss in detail the results published in AIP Advances 3, 042103 (2013).

  16. Inelastic x-ray scattering in vicinity of xenon L{sub 3} edge

    SciTech Connect

    Zitnik, M.; Kavcic, M.; Bucar, K.; Mihelic, A.; Stuhec, M.; Kokalj, J.; Szlachetko, J.

    2007-09-15

    A series of x-ray emission spectra of xenon in the region of L{sub 3}M{sub 5,4}(L{alpha}{sub 1,2}) and L{sub 3}N{sub 5,4}(L{beta}{sub 2,15}) lines were recorded along the polarization direction of the incoming photons with energies ranging from 4779.4 to 4804.4 eV. A combination of monochromatic photon beam and high resolution x-ray spectrometer resulted in the experimental broadening of 1 eV allowing the observation of resonantly enhanced and narrowed emission lines from the decay of [2p{sub 3/2}]nd,ns states. The measured spectra are decomposed into the continuum and resonant contributions to determine their relative emission strengths and the energies of the lowest resonant excitations converging to the L{sub 3} edge. The calculated differential cross section for inelastically scattered photons is compared to the measured data. Each of the resonant states is described by a single relativistic configuration in the frame of the Dirac-Fock model, and the continuum contribution to the scattered light is evaluated within the Caldwell-Zare approach, which neglects anisotropic interaction of the ejected electron with the ion.

  17. Phonon density of states in nanocrystalline Si1-xGex explored by inelastic neutron scattering

    NASA Astrophysics Data System (ADS)

    Wilson, Stephen; Dhital, Chetan; Ren, Zhifeng; Abernathy, Doug

    2012-02-01

    Recently there have been significant advances in the efficiencies of traditional thermoelectric compounds gained via the creation of thermoelectric nanocomposites possessing substantially reduced thermal conductivity relative to their bulk counterparts [1,2]. The dramatic reduction in the heat transport of these nanocomposites is often attributed to the increased interface scattering of phonons or induced surface/boundary modes; however notably little work has been put worth into exploring the detailed changes in the phonon density of states in many of these functional nanocomposite samples. Here we present inelastic neutron scattering measurements exploring the phonon density of states in a series of Si1-xGex thermoelectric nanocomposites. The evolution of the phonon spectral weight distribution and linewidths as a function of Ge-doping will be discussed and compared to the known bulk phonon density of states in this system. [4pt] [1] Giri Joshi et al., Nano Letters 8, 4670 (2008). [0pt] [2] X. Wang et al., App. Phys. Lett. 93, 193121 (2008).

  18. Band Structure of Helimagnons in MnSi Resolved by Inelastic Neutron Scattering.

    PubMed

    Kugler, M; Brandl, G; Waizner, J; Janoschek, M; Georgii, R; Bauer, A; Seemann, K; Rosch, A; Pfleiderer, C; Böni, P; Garst, M

    2015-08-28

    A magnetic helix realizes a one-dimensional magnetic crystal with a period given by the pitch length λh. Its spin-wave excitations-the helimagnons-experience Bragg scattering off this periodicity, leading to gaps in the spectrum that inhibit their propagation along the pitch direction. Using high-resolution inelastic neutron scattering, the resulting band structure of helimagnons was resolved by preparing a single crystal of MnSi in a single magnetic-helix domain. At least five helimagnon bands could be identified that cover the crossover from flat bands at low energies with helimagnons basically localized along the pitch direction to dispersing bands at higher energies. In the low-energy limit, we find the helimagnon spectrum to be determined by a universal, parameter-free theory. Taking into account corrections to this low-energy theory, quantitative agreement is obtained in the entire energy range studied with the help of a single fitting parameter. PMID:26371678

  19. Diffractive deep inelastic scattering in an AdS/CFT inspired model: A phenomenological study

    SciTech Connect

    Betemps, M. A.; Goncalves, V. P.; Santana Amaral, J. T. de

    2010-05-01

    The analytical treatment of the nonperturbative QCD dynamics is one of the main open questions of the strong interactions. Currently, it is only possible to get some qualitative information about this regime considering other QCD-like theories, as, for example, the N=4 super Yang-Mills theory, where one can perform calculations in the nonperturbative limit of large 't Hooft coupling using the anti-de Sitter space/conformal field theory (AdS/CFT). Recently, the high energy scattering amplitude was calculated in the AdS/CFT approach, applied to deep-inelastic scattering and confronted with the F{sub 2} HERA data. In this work we extend the nonperturbative AdS/CFT inspired model for diffractive processes and compare its predictions with a perturbative approach based on the Balitsky-Kovchegov equation. We demonstrate that the AdS/CFT inspired model is not able to describe the current F{sub 2}{sup D(3)} HERA data and predicts a similar behavior to that from the Balitsky-Kovchegov equation in the range 10{sup -7} < or approx. x{sub P} < or approx. 10{sup -4}. At smaller values of x{sub P} the diffractive structure function is predicted to be energy independent.

  20. Hydrophobic hydration of tert-butyl alcohol studied by Brillouin light and inelastic ultraviolet scattering

    NASA Astrophysics Data System (ADS)

    Lupi, L.; Comez, L.; Masciovecchio, C.; Morresi, A.; Paolantoni, M.; Sassi, P.; Scarponi, F.; Fioretto, D.

    2011-02-01

    The longitudinal viscosity of diluted water-tert-butyl alcohol solutions in the 10 GHz frequency region has been measured by means of Brillouin light scattering and inelastic ultraviolet scattering. The main advantage of our hypersonic investigation compared to more traditional ultrasonic measurements is that in the gigahertz frequency range slow relaxation processes involving the alcohol dynamics are completely unrelaxed, so that the measured viscosity mainly originates from the hydrogen bond restructuring of water. In contrast with previous determinations, we estimate an activation energy which is independent from the alcohol mole fraction up to X = 0.1, and comparable to that of bulk water. A simple two-component model is used to describe the steep increase of viscosity with increasing alcohol mole fraction, and a retardation factor 1.7 ± 0.2 is found between the relaxation times of hydration and bulk water. These findings endorse a dynamic scenario where the slowing down of hydration water is mainly due to a reduction of configurational entropy and does not involve an arrested, icelike, dynamics.

  1. {sup {bold 6}}Li(vector)+{sup {bold 12}}C inelastic scattering at 30 and 50 MeV

    SciTech Connect

    Kerr, P.L.; Kemper, K.W.; Green, P.V.; Mohajeri, K.; Myers, E.G.; Schmidt, B.G.; Hnizdo, V.

    1996-09-01

    A complete set of analyzing powers (AP`s), {ital iT}{sub 11}, {ital T}{sub 20}, {ital T}{sub 21}, and {ital T}{sub 22}, for 50 MeV {sup 12}C({sup 6}Li(vector),{sup 6}Li) elastic scattering and inelastic scattering to the {sup 12}C(2{sup +}, 4.44 MeV), {sup 12}C(0{sup +}, 7.65 MeV), and {sup 12}C(3{sup {minus}}, 9.64 MeV) states over the center-of-mass (c.m.) angular range 10{degree}{endash}115{degree} is reported. In addition, cross sections for the excited states 3{sup +}(2.18 MeV), 2{sup +}(4.31 MeV), and 1{sup +}(5.65 MeV) of {sup 6}Li were measured by using the inverse-kinematics reaction {sup 6}Li({sup 12}C,{sup 12}C) at 100 MeV. A combined analysis of the new 50 MeV data and previous 30 MeV data has been carried out using the coupled-channels (CC) code FRESCO. The CC calculations use an optical potential with double-folded (DF) real central, Woods-Saxon imaginary central, and Thomas real spin-orbit (SO) potentials. Calculations include reorientation terms and coupling to the first three excited states of {sup 6}Li and the first two nonzerospin states of {sup 12}C. The {sup 6}Li coupling strengths were fixed by the measured {sup 6}Li excited-state cross sections. The elastic-scattering cross sections and A.P.`s are described well. The need for an explicit SO potential is apparent in the elastic and inelastic-scattering AP`s {ital iT}{sub 11}, more so at 30 MeV than at 50 MeV. The rank-2 AP`s up to 50{degree} c.m. arise mainly from ground-state reorientation effects. The DF potential normalization constant {ital N} approaches unity for the 50 MeV data. At both energies, the {sup 12}C(2{sup +}) cross sections are underestimated at large angles, and the description of the {sup 12}C(3{sup {minus}}) cross sections is poor in detail. The {sup 12}C(3{sup {minus}}) AP`s and the {sup 12}C(2{sup +}) {ital iT}{sub 11} are not reproduced at either energy. {copyright} {ital 1996 The American Physical Society.}

  2. Resonant inelastic light scattering studies in the fractional quantum Hall regime, and of phase transitions in relaxor ferroelectrics

    NASA Astrophysics Data System (ADS)

    Dujovne, Irene

    This dissertation presents inelastic light scattering results that probe low energy physics in quantum liquids and in materials with novel contemporary applications. Two areas are considered: (a) low-lying excitations in two dimensional structures under the extreme conditions that occur in the fractional quantum Hall regime (FQH), (b) low energy vibrational modes in relaxor ferroelectrics. In the FQH regime we concentrate in the region 1/2 ≥ nu ≥ 1/3. We discovered new spin-flip excitations that provide insight into composite fermions (CF) energy level spacings and interactions. In the filling factor region 2/5 ≥ nu ≥ 1/3 we uncover new excitations that extend to filling factors between the main fractions of the FQH effect and can be associated to transitions between different CF Landau levels. These results provide information on residual interactions between the CFs. We find that residual interactions are not negligible and could lead to novel behaviors. An analysis of the density dependence of CF energy levels at filling factors nu = 1/3 and nu = 2/5 based on simple energy level models is presented. The main assumptions are that the splitting between quasiparticle levels and spin reversal energies are proportional to the Coulomb energy. Energy level structures of CF quasiparticles are also probed by means of light scattering experiments with spin-flip excitations at nu = 3/7 and nu = 4/9. Measurements of spin excitations in the limit of nu → 1/2 uncover a delicate balance between spin reversal and Fermi energies. The interactions are exposed in low-lying spin-flip excitations that have marked sensitivity to the state of spin polarization of the system when nu → 1/2. We are able to determine the boundaries between full and partial spin polarization, these, together with the observation of spin-flip rotons reveal spin reversal energies much larger than the bare Zeeman splitting. Inelastic light scattering by optical phonons (Raman scattering) in

  3. Anharmonic lattice dynamics of Ag2O studied by inelastic neutron scattering and first-principles molecular dynamics simulations

    SciTech Connect

    Lan, Tian; Li, Chen; Niedziela, Jennifer L; Smith, Hillary; Abernathy, Douglas L; Rossman, George; Fultz, B.

    2014-01-01

    Inelastic neutron scattering measurements on silver oxide (Ag2O) with the cuprite structure were performed at temperatures from 40 to 400 K, and Fourier transform far-infrared spectra were measured from 100 to 300 K. The measured phonon densities of states and the infrared spectra showed unusually large energy shifts with temperature, and large linewidth broadenings. First principles molecular dynamics (MD) calculations were performed at various temperatures, successfully accounting for the negative thermal expansion (NTE) and local dynamics. Using the Fourier-transformed velocity autocorrelation method, the MD calculations reproduced the large anharmonic effects of Ag2O, and were in excellent agreement with the neutron scattering data. The quasiharmonic approximation (QHA) was less successful in accounting for much of the phonon behavior. The QHA could account for some of the NTE below 250 K, although not at higher temperatures. Strong anharmonic effects were found for both phonons and for the NTE. The lifetime broadenings of Ag2O were explained by anharmonic perturbation theory, which showed rich interactions between the Ag-dominated modes and the O-dominated modes in both up- and down-conversion processes.

  4. Inelastic neutron scattering and molecular simulation of the dynamics of interlayer water in smectite clay minerals

    SciTech Connect

    Cygan, Randall T.; Daemen, Luke L.; Ilgen, Anastasia G.; Krumhansl, James L.; Nenoff, Tina M.

    2015-11-16

    The study of mineral–water interfaces is of great importance to a variety of applications including oil and gas extraction, gas subsurface storage, environmental contaminant treatment, and nuclear waste repositories. Understanding the fundamentals of that interface is key to the success of those applications. Confinement of water in the interlayer of smectite clay minerals provides a unique environment to examine the interactions among water molecules, interlayer cations, and clay mineral surfaces. Smectite minerals are characterized by a relatively low layer charge that allows the clay to swell with increasing water content. Montmorillonite and beidellite varieties of smectite were investigated to compare the impact of the location of layer charge on the interlayer structure and dynamics. Inelastic neutron scattering of hydrated and dehydrated cation-exchanged smectites was used to probe the dynamics of the interlayer water (200–900 cm–1 spectral region) and identify the shift in the librational edge as a function of the interlayer cation. Molecular dynamics simulations of equivalent phases and power spectra, derived from the resulting molecular trajectories, indicate a general shift in the librational behavior with interlayer cation that is generally consistent with the neutron scattering results for the monolayer hydrates. Both neutron scattering and power spectra exhibit librational structures affected by the location of layer charge and by the charge of the interlayer cation. Furthermore, divalent cations (Ba2+ and Mg2+) characterized by large hydration enthalpies typically exhibit multiple broad librational peaks compared to monovalent cations (Cs+ and Na+), which have relatively small hydration enthalpies.

  5. Inelastic neutron scattering and molecular simulation of the dynamics of interlayer water in smectite clay minerals

    DOE PAGESBeta

    Cygan, Randall T.; Daemen, Luke L.; Ilgen, Anastasia G.; Krumhansl, James L.; Nenoff, Tina M.

    2015-11-16

    The study of mineral–water interfaces is of great importance to a variety of applications including oil and gas extraction, gas subsurface storage, environmental contaminant treatment, and nuclear waste repositories. Understanding the fundamentals of that interface is key to the success of those applications. Confinement of water in the interlayer of smectite clay minerals provides a unique environment to examine the interactions among water molecules, interlayer cations, and clay mineral surfaces. Smectite minerals are characterized by a relatively low layer charge that allows the clay to swell with increasing water content. Montmorillonite and beidellite varieties of smectite were investigated to comparemore » the impact of the location of layer charge on the interlayer structure and dynamics. Inelastic neutron scattering of hydrated and dehydrated cation-exchanged smectites was used to probe the dynamics of the interlayer water (200–900 cm–1 spectral region) and identify the shift in the librational edge as a function of the interlayer cation. Molecular dynamics simulations of equivalent phases and power spectra, derived from the resulting molecular trajectories, indicate a general shift in the librational behavior with interlayer cation that is generally consistent with the neutron scattering results for the monolayer hydrates. Both neutron scattering and power spectra exhibit librational structures affected by the location of layer charge and by the charge of the interlayer cation. Furthermore, divalent cations (Ba2+ and Mg2+) characterized by large hydration enthalpies typically exhibit multiple broad librational peaks compared to monovalent cations (Cs+ and Na+), which have relatively small hydration enthalpies.« less

  6. Deep inelastic neutron scattering from orthorhombic ordered HCl: Short-time proton dynamics and anomalous neutron cross sections

    SciTech Connect

    Senesi, R.; Colognesi, D.; Pietropaolo, A.; Abdul-Redah, T.

    2005-08-01

    Deep inelastic neutron scattering measurements from orthorhombic ordered HCl are presented and analyzed in order to clarify the problem of an anomalous deficit in the neutron-proton cross section found in previous experiments on various materials. A reliable model for the HCl short-time single-particle dynamics, including atomic vibrational anisotropies and deviations from the impulsive approximation, is set up. The model HCl response function is transformed into simulated time-of-flight spectra, taking carefully into account the effects of instrumental resolution and the filter absorption profile used for neutron energy analysis. Finally, the experimental values of the anomalous reduction factor for the neutron-proton cross section are extracted by comparing simulated and experimental data. Results show a 34% reduction of the H cross section, varying with the scattering angle in a range centered at 53 deg. In addition, the same approximate procedure used in earlier studies is also employed, providing results in reasonable agreement with the more rigorous ones, and confirming the substantial reliability of the past work on this subject.

  7. Interplay of the elastic and inelastic channels in the 16O+27Al scattering at Elab = 280 MeV

    NASA Astrophysics Data System (ADS)

    Cappuzzello, F.; Nicolosi, D.; Linares, R.; Oliveira, J. R. B.; Lubian, J.; Agodi, C.; Carbone, D.; Cavallaro, M.; de Faria, P. N.; Foti, A.; Rodrigues, M. R. D.

    2016-06-01

    Recent data indicated a nuclear rainbow-like pattern in the elastic scattering of 16O + 27Al at E_{lab}=100 MeV that arises from couplings of the ground to the low-lying states of the 27Al nucleus. Similar effect was identified in the elastic angular distribution of 16O + 12C at E_{lab}=281 and 330 MeV. These experiments show a crucial role of microscopic details of nuclear structure in the elastic scattering of heavy ions at energies well above the Coulomb barrier. In this work we investigate the 16O + 27Al system at E_{lab}=280 MeV for which a coupled channel calculation predicts a pronounced nuclear rainbow-like structure. Obtained experimental data show evidences of an important coupling of the elastic channel to the inelastic. Coupled channel calculations reproduce the experimental angular distributions when a re-normalization factor on the real part of the optical potential is introduced. A proper theoretical approach still requires a high degree of accuracy for the nuclear structure models and new tools to deal with collective excitations.

  8. Quantum scattering studies of electronically inelastic collisions of N + 2(X 2Sigma + g, A 2Pi u) with He

    NASA Astrophysics Data System (ADS)

    Berning, Andreas; Werner, Hans-Joachim

    1994-02-01

    The potential energy surfaces (PESs) of the three lowest electronic states of the system N+2+He have been computed using accurate multiconfiguration-reference configuration (MRCI) wave functions and a large basis set. The approach of the He atom leads to nonadiabatic mixing of the A 2Πu(A') and X 2Σ+g(A') states of N+2. The three adiabatic interaction potentials have been transformed into a set of four diabatic potentials, one of which describes the collision-induced nonadiabatic coupling between the two A' states. The computed potentials have been fitted to analytical functions and used in quantum scattering calculations for electronically inelastic transitions between individual rovibrational levels of the A 2Πu and the X 2Σ+g states of N+2. Our results are compared to transitions observed experimentally by Katayama and co-workers between the rotational levels of the A,v=3 and 4 and X,v=6, 7, and 8 vibrational manifolds. In general, good agreement is found for transitions between nearly isoenergetic vibrational states. However, for transitions which traverse large energy gaps, we obtained cross sections which are several orders of magnitude smaller than experimentally observed. Inclusion of the vibrational degree of freedom of the N+2 molecule in the scattering calculations was found to have only an insignificant effect on the transition probabilities.

  9. Measurement of unpolarized differential cross section of semi-inclusive deep-inelastic scattering on a 3He target

    NASA Astrophysics Data System (ADS)

    Yan, Xuefei; Jefferson Lab E06-010 Collaboration

    2015-10-01

    Jefferson Lab experiment E06-010 was performed with 5.9 GeV polarized e- beam on a transversely polarized 3He target. The produced hadrons at semi-inclusive deep-inelastic scattering (SIDIS) kinematics were detected in the high-resolution spectrometer (HRS) in coincidence with the scattered electrons detected by the BigBite spectrometer. The kinematic coverage focuses on the valence quark region, x = 0.1 to 0.4, at Q2 = 1 to 3 (GeV/c)2. Previous analysis effort has been focused on extracting single-spin asymmetry (SSA) and double-spin asymmetry (DSA) related to various TMDs such as Transversity, Sivers, Pretzelosity and Transverse Helicity (g1Tq). The extracted unpolarized differential cross section will put important constraints on the Cahn effect of SIDIS and the Boer-Mulders function. In this talk we will present new results on extracted unpolarized differential cross section of SIDIS in channels e- + 3He --> e-' + π+/- + X. A dedicated study of the acceptance of HRS and BigBite spectrometers, as well as updated study of the efficiencies and particle contamination in the experiment allowed us to control systematic uncertainties to an acceptable level. This work is supported in part by the US Department of Energy under Contract Numbers DE-FG02-03ER41231.

  10. Vibration-induced inelastic effects in the electron transport through multisite molecular bridges.

    PubMed

    Zimbovskaya, Natalya A; Kuklja, Maija M

    2009-09-21

    We theoretically analyzed inelastic effects in the electron transport through molecular junctions originating from electron-vibron interactions. The molecular bridge was simulated by a periodical chain of identical hydrogenlike atoms with the nearest neighbors interaction thus providing a set of energy states for the electron tunneling. To avoid difficulties inevitably arising when advanced computational techniques are employed to study inelastic electron transport through multilevel bridges, we propose and develop a semiphenomenological approach. The latter is based on Buttiker's dephasing model within the scattering matrix formalism. We apply the proposed approach to describe features associated with electron energy transfer to vibrational phonons that appear in the second derivative of the current in the junction with respect to the bias voltage. In the particular case of a single level bridge our results agree with those obtained by proper calculations carried out within the nonequilibrium Green's functions method indicating the usefulness of the suggested approach.

  11. High-resolution inelastic x-ray scattering to study the high-frequency atomic dynamics of disordered systems

    NASA Astrophysics Data System (ADS)

    Monaco, Giulio

    2008-06-01

    The use of momentum-resolved inelastic x-ray scattering with meV energy resolution to study the high-frequency atomic dynamics in disordered systems is here reviewed. The typical realization of this experiment is described together with some common models used to interpret the measured spectra and to extract parameters of interest for the investigation of disordered systems. With the help of some selected examples, the present status of the field is discussed. Particular attention is given to those results which are still open for discussion or controversial, and which will require further development of the technique to be fully solved. Such an instrumental development seems nowadays possible at the light of recently proposed schemes for advanced inelastic x-ray scattering spectrometers. To cite this article: G. Monaco, C. R. Physique 9 (2008).

  12. Observation of isoscalar multipole strengths in exotic doubly-magic 56Ni in inelastic α scattering in inverse kinematics

    NASA Astrophysics Data System (ADS)

    Bagchi, S.; Gibelin, J.; Harakeh, M. N.; Kalantar-Nayestanaki, N.; Achouri, N. L.; Akimune, H.; Bastin, B.; Boretzky, K.; Bouzomita, H.; Caamaño, M.; Càceres, L.; Damoy, S.; Delaunay, F.; Fernández-Domínguez, B.; Fujiwara, M.; Garg, U.; Grinyer, G. F.; Kamalou, O.; Khan, E.; Krasznahorkay, A.; Lhoutellier, G.; Libin, J. F.; Lukyanov, S.; Mazurek, K.; Najafi, M. A.; Pancin, J.; Penionzhkevich, Y.; Perrot, L.; Raabe, R.; Rigollet, C.; Roger, T.; Sambi, S.; Savajols, H.; Senoville, M.; Stodel, C.; Suen, L.; Thomas, J. C.; Vandebrouck, M.; Van de Walle, J.

    2015-12-01

    The Isoscalar Giant Monopole Resonance (ISGMR) and the Isoscalar Giant Dipole Resonance (ISGDR) compression modes have been studied in the doubly-magic unstable nucleus 56Ni. They were measured by inelastic α-particle scattering in inverse kinematics at 50 MeV/u with the MAYA active target at the GANIL facility. The centroid of the ISGMR has been obtained at Ex = 19.1 ± 0.5 MeV. Evidence for the low-lying part of the ISGDR has been found at Ex = 17.4 ± 0.7 MeV. The strength distribution for the dipole mode shows similarity with the prediction from the Hartree-Fock (HF) based random-phase approximation (RPA) [1]. These measurements confirm inelastic α-particle scattering as a suitable probe for exciting the ISGMR and the ISGDR modes in radioactive isotopes in inverse kinematics.

  13. Ultrahigh-Energy Neutrino-Nucleon Deep-Inelastic Scattering and the Froissart Bound

    SciTech Connect

    Illarionov, Alexey Yu.; Kniehl, Bernd A.; Kotikov, Anatoly V.

    2011-06-10

    We present a simple formula for the total cross section {sigma}{sup {nu}}N of neutral- and charged-current deep-inelastic scattering of ultrahigh-energy neutrinos on isoscalar nuclear targets, which is proportional to the structure function F{sub 2}{sup {nu}}N(M{sub V}{sup 2}/s,M{sub V}{sup 2}), where M{sub V} is the intermediate-boson mass and s is the square of the center-of-mass energy. The coefficient in front of F{sub 2}{sup {nu}}N(x,Q{sup 2}) depends on the asymptotic low-x behavior of F{sub 2}{sup {nu}}N. It contains an additional lns term if F{sub 2}{sup {nu}}N scales with a power of ln(1/x). Hence, an asymptotic low-x behavior F{sub 2}{sup {nu}}N{proportional_to}ln{sup 2}(1/x), which is frequently assumed in the literature, already leads to a violation of the Froissart bound on {sigma}{sup {nu}}N.

  14. Dynamics of confined water reconstructed from inelastic x-ray scattering measurements of bulk response functions

    NASA Astrophysics Data System (ADS)

    Coridan, Robert H.; Schmidt, Nathan W.; Lai, Ghee Hwee; Abbamonte, Peter; Wong, Gerard C. L.

    2012-03-01

    Nanoconfined water and surface-structured water impacts a broad range of fields. For water confined between hydrophilic surfaces, measurements and simulations have shown conflicting results ranging from “liquidlike” to “solidlike” behavior, from bulklike water viscosity to viscosity orders of magnitude higher. Here, we investigate how a homogeneous fluid behaves under nanoconfinement using its bulk response function: The Green's function of water extracted from a library of S(q,ω) inelastic x-ray scattering data is used to make femtosecond movies of nanoconfined water. Between two confining surfaces, the structure undergoes drastic changes as a function of surface separation. For surface separations of ≈9 Å, although the surface-associated hydration layers are highly deformed, they are separated by a layer of bulklike water. For separations of ≈6 Å, the two surface-associated hydration layers are forced to reconstruct into a single layer that modulates between localized “frozen’ and delocalized “melted” structures due to interference of density fields. These results potentially reconcile recent conflicting experiments. Importantly, we find a different delocalized wetting regime for nanoconfined water between surfaces with high spatial frequency charge densities, where water is organized into delocalized hydration layers instead of localized hydration shells, and are strongly resistant to `freezing' down to molecular distances (<6 Å).

  15. Characterization of ammonia adsorption on ruthenium sulfide: Identification of amino species by inelastic neutron scattering

    SciTech Connect

    Jobic, H.; Lacroix, M.; Decamp, T.

    1995-12-01

    The interaction of ammonia with the surface of a model ruthenium sulfide catalyst has been investigated using conventional adsorption measurements, temperature programmed desorption and inelastic neutron scattering. This work has provided evidence that the amount and also the nature of adsorbed species vary with the sulfur to metal ratio of the solid. On the unreduced sample, ammonia interacts weakly with the solid and ammonium ions are not observed. On the partially desulfurized catalyst, the chemisorption of ammonia is dissociative. The NH{sub 2} fragment is bonded to a coordinatively unsaturated ruthenium ion formed upon reduction of the solid while the proton is trapped by a sulfur anion leading to the formation of SH groups. It was previously shown that hydrogen adsorption also involves unsaturated sites. Adsorption of ND{sub 3} on a hydrogen-covered surface provokes a desorption of HD indicating that a competition of adsorption occurs between hydrogen and ammonia. This result explains why ammonia generally acts as a poison for hydrogenation, hydrodenitrogenation, and hydrodesulfurization reactions. 33 refs., 11 figs., 2 tabs.

  16. Magnetic spectra in the tridiminished-icosahedron {Fe9} nanocluster by inelastic neutron scattering

    SciTech Connect

    Vaknin, David; Demmel, Franz

    2014-05-01

    Inelastic neutron scattering (INS) experiments under applied magnetic field at low temperatures show detailed low-lying magnetic excitations in the so-called tridiminshed iron icosahedron magnetic molecule. The magnetic molecule consists of nine iron Fe3+ (s=5/2) and three phosphorous atoms that are situated on the 12 vertices of a nearly perfect icosahedron. The three phosphorous atoms form a plane that separates the iron cluster into two weakly coupled three- and six-ion fragments, {Fe3} and {Fe6}, respectively. The magnetic field INS results exhibit an S=1/2 ground state expected from a perfect equilateral triangle of the {Fe3} triad with a powder averaged g value =2.00. Two sets of triplet excitations whose temperature and magnetic field dependence indicate an S=0 ground state with two nondegenerate S=1 states are attributed to the {Fe6} fragment. The splitting may result from a finite coupling between the two fragments, single-ion anisotropy, antisymmetric exchange couplings, or from magnetic frustration of its triangular building blocks.

  17. Inelastic x-ray scattering of dense solid oxygen: Evidence for intermolecular bonding

    SciTech Connect

    Meng, Yue; Eng, Peter J.; Tse, John S.; Shaw, Dawn M.; Hu, Michael Y.; Shu, Jinfu; Gramsch, Stephen A.; Kao, Chichang; Hemley, Russell J.; Mao, Ho-kwang

    2008-08-14

    The detailing of the intermolecular interactions in dense solid oxygen is essential for an understanding of the rich polymorphism and remarkable properties of this element at high pressure. Synchrotron inelastic x-ray scattering measurements of oxygen K-edge excitations to 38 GPa reveal changes in electronic structure and bonding on compression of the molecular solid. The measurements show that O{sub 2} molecules interact predominantly through the half-filled 1{pi}{sub g}* orbital <10 GPa. Enhanced intermolecular interactions develop because of increasing overlap of the 1{pi}{sub g}* orbital in the low-pressure phases, leading to electron delocalization and ultimately intermolecular bonding between O{sub 2} molecules at the transition to the {epsilon}-phase. The {epsilon}-phase, which consists of (O{sub 2}){sub 4} clusters, displays the bonding characteristics of a closed-shell system. Increasing interactions between (O{sub 2}){sub 4} clusters develop upon compression of the {epsilon}-phase, and provide a potential mechanism for intercluster bonding in still higher-pressure phases.

  18. Partially coherent wavefront propagation simulations for inelastic x-ray scattering beamline including crystal optics

    NASA Astrophysics Data System (ADS)

    Suvorov, Alexey; Cai, Yong Q.; Sutter, John P.; Chubar, Oleg

    2014-09-01

    Up to now simulation of perfect crystal optics in the "Synchrotron Radiation Workshop" (SRW) wave-optics computer code was not available, thus hindering the accurate modelling of synchrotron radiation beamlines containing optical components with multiple-crystal arrangements, such as double-crystal monochromators and high-energy-resolution monochromators. A new module has been developed for SRW for calculating dynamical diffraction from a perfect crystal in the Bragg case. We demonstrate its successful application to the modelling of partially-coherent undulator radiation propagating through the Inelastic X-ray Scattering (IXS) beamline of the National Synchrotron Light Source II (NSLS-II) at Brookhaven National Laboratory. The IXS beamline contains a double-crystal and a multiple-crystal highenergy- resolution monochromator, as well as complex optics such as compound refractive lenses and Kirkpatrick-Baez mirrors for the X-ray beam transport and shaping, which makes it an excellent case for benchmarking the new functionalities of the updated SRW codes. As a photon-hungry experimental technique, this case study for the IXS beamline is particularly valuable as it provides an accurate evaluation of the photon flux at the sample position, using the most advanced simulation methods and taking into account parameters of the electron beam, details of undulator source, and the crystal optics.

  19. Parity Violating Deep Inelastic Electron Scattering from the Deuteron at 6 GeV

    SciTech Connect

    Pan, Kai

    2013-02-01

    An experiment that measured the parity violating (PV) asymmetry Ad in e-2H deep inelastic scattering (DIS) at Q2 ~ 1.10 and 1.90 (GeV/c)2 and xB ~ 0.3 was completed in experimental Hall A at the Thomas Jefferson National Accelerator Facility. The asymmetry can be used to extract the neutral weak coupling combination (2C2u-C2d), providing a factor of five to six improvement over the current world data. To achieve this precision, asymmetries of the 10-4 level needed to be measured at event rates up to 500 kHz with high electron detection efficiency and high pion background rejection capability. A specialized scaler-based counting data acquisition system (DAQ) with hardware-based particle identification was successfully implemented. The statistical quality of the asymmetry measurement agreed with the Gaussian distribution to over five orders of magnitudes and the experimental goal of 3-4% statistical uncertainty was achieved. The design and performance of the new DAQ system is presented with the preliminary asymmetry results given in the end.

  20. ''Inelastic Neutron Scattering and Periodic Density Functional Studies of Hydrogen Bonded Structures''

    SciTech Connect

    Bruce S. Hudson

    2004-10-27

    This project is directed at a fundamental understanding of hydrogen bonding, the primary reversible interaction leading to defined geometries, networks and supramolecular aggregates formed by organic molecules. Hydrogen bonding is still not sufficiently well understood that the geometry of such supramolecular aggregates can be predicted. In the approach taken existing quantum chemical methods capable of treating periodic solids have been applied to hydrogen bonded systems of known structure. The equilibrium geometry for the given space group and packing arrangement were computed and compared to that observed. The second derivatives and normal modes of vibration will then be computed and from this inelastic neutron scattering (INS) spectra were computed using the normal mode eigenvectors to compute spectral intensities. Appropriate inclusion of spectrometer line width and shape was made in the simulation and overtones, combinations and phonon wings were be included. These computed spectra were then compared with experimental results obtained for low-temperature polycrystalline samples at INS spectrometers at several facilities. This procedure validates the computational methodology for describing these systems including both static and dynamic aspects of the material. The resulting description can be used to evaluate the relative free energies of two or more proposed structures and so ultimately to be able to predict which structure will be most stable for a given building block.

  1. Reaction intermediates in the catalytic Gif-type oxidation from nuclear inelastic scattering

    NASA Astrophysics Data System (ADS)

    Rajagopalan, S.; Asthalter, T.; Rabe, V.; Laschat, S.

    2016-12-01

    Nuclear inelastic scattering (NIS) of synchrotron radiation, also known as nuclear resonant vibrational spectroscopy (NRVS), has been shown to provide valuable insights into metal-centered vibrations at Mössbauer-active nuclei. We present a study of the iron-centered vibrational density of states (VDOS) during the first step of the Gif-type oxidation of cyclohexene with a novel trinuclear Fe3(μ 3-O) complex as catalyst precursor. The experiments were carried out on shock-frozen solutions for different combinations of reactants: Fe3(μ 3-O) in pyridine solution, Fe3(μ 3-O) plus Zn/acetic acid in pyridine without and with addition of either oxygen or cyclohexene, and Fe3(μ 3-O)/Zn/acetic acid/pyridine/cyclohexene (reaction mixture) for reaction times of 1 min, 5 min, and 30 min. The projected VDOS of the Fe atoms was calculated on the basis of pseudopotential density functional calculations. Two possible reaction intermediates were identified as [Fe(III)(C5H5N)2(O2CCH3)2]+ and Fe(II)(C5H5N)4(O2CCH3)2, yielding evidence that NIS (NRVS) allows to identify the presence of iron-centered intermediates also in complex reaction mixtures.

  2. Inelastic neutron scattering study on boson peaks of imidazolium-based ionic liquids

    DOE PAGESBeta

    Kofu, Maiko; Inamura, Yasuhiro; Podlesnyak, Andrey A.; Ehlers, Georg; Yamamuro, Osamu; Moriya, Yosuke

    2015-07-26

    Low energy excitations of 1-alkyl-3-methylimidazolium ionic liquids (ILs) have been investigated by means of neutron spectroscopy. In the spectra of inelastic scattering, a broad excitation peak referred to as a “boson peak” appeared at 1–3 meV in all of the ILs measured. The intensity of the boson peak was enhanced at the Q positions corresponding to the diffraction peaks, reflecting the in-phase vibrational nature of the boson peak. Furthermore the boson peak energy (EBP) was insensitive to the length of the alkyl-chain but changed depending on the radius of the anion. From the correlation among EBP, the anion radius, andmore » the glass transition temperature Tg, we conclude that both EBP and Tg in ILs are predominantly governed by the inter-ionic Coulomb interaction which is less influenced by the alkyl-chain length. Furthermore, we also found that the EBP is proportional to the inverse square root of the molecular weight as observed in molecular glasses.« less

  3. Inelastic neutron scattering study on boson peaks of imidazolium-based ionic liquids

    SciTech Connect

    Kofu, Maiko; Inamura, Yasuhiro; Podlesnyak, Andrey A.; Ehlers, Georg; Yamamuro, Osamu; Moriya, Yosuke

    2015-07-26

    Low energy excitations of 1-alkyl-3-methylimidazolium ionic liquids (ILs) have been investigated by means of neutron spectroscopy. In the spectra of inelastic scattering, a broad excitation peak referred to as a “boson peak” appeared at 1–3 meV in all of the ILs measured. The intensity of the boson peak was enhanced at the Q positions corresponding to the diffraction peaks, reflecting the in-phase vibrational nature of the boson peak. Furthermore the boson peak energy (EBP) was insensitive to the length of the alkyl-chain but changed depending on the radius of the anion. From the correlation among EBP, the anion radius, and the glass transition temperature Tg, we conclude that both EBP and Tg in ILs are predominantly governed by the inter-ionic Coulomb interaction which is less influenced by the alkyl-chain length. Furthermore, we also found that the EBP is proportional to the inverse square root of the molecular weight as observed in molecular glasses.

  4. Momentum space saturation model for deep inelastic scattering and single inclusive hadron production

    NASA Astrophysics Data System (ADS)

    Basso, E. A. F.; Gay Ducati, M. B.; de Oliveira, E. G.

    2011-08-01

    We show how the Santana Amaral-Gay Ducati-Betemps-Soyez (AGBS) model, originally developed for deep inelastic scattering applied to HERA data on the proton structure function, can also describe the RHIC data on single inclusive hadron yield for d+Au and p+p collisions through a new simultaneous fit. The single inclusive hadron production is modeled through the color glass condensate, which uses the quark (and gluon) condensate amplitudes in momentum space. The AGBS model is also a momentum space model based on the asymptotic solutions of the Balitsky-Kovchegov equation, although a different definition of the Fourier transform is used. This aspect is overcome, and a description entirely in transverse momentum of both processes arises for the first time. The small difference between the simultaneous fit and the one for HERA data alone suggests that the AGBS model describes very well both kinds of processes and thus emerges as a good tool to investigate the inclusive hadron production data. We use this model for predictions at LHC energies, which agrees very well with available experimental data.

  5. Inelastic neutron scattering study of Pt(II) complexes displaying anticancer properties.

    PubMed

    de Carvalho, Luís A E Batista; Marques, M Paula M; Martin, Christine; Parker, Stewart F; Tomkinson, John

    2011-05-01

    The well-known platinum(II) chemotherapeutic drugs cisplatin [cis-(NH(3))(2)PtCl(2)] and carboplatin [Pt(NH(3))(2)C(6)O(4)H(6)], as well as the analogous transplatin [trans-(NH(3))(2)PtCl(2)], were studied by inelastic neutron scattering (INS) spectroscopy, coupled to quantum mechanical methods, and some ancillary work with X-ray diffraction on powders. An assignment of the experimental spectra was carried out based on the calculated INS transition frequencies and intensities (at the DFT level), thereby achieving a good correspondence between the calculated and observed data. Unusually good-quality INS spectra were obtained from about 250 mg, which is the smallest sample of a hydrogenous compound for which a successful INS interpretation has been reported. The knowledge of the local configuration of this kind of complexes is essential for an accurate understanding of their activity, which will pave the way for the rational design of novel third-generation drugs comprising cisplatin- and carboplatin-like moieties. PMID:21523878

  6. Inelastic Neutron Scattering on Multiferroics NdFe3(BO3)4

    NASA Astrophysics Data System (ADS)

    Hayashida, Shohei; Soda, Minoru; Itoh, Shinichi; Yokoo, Tetsuya; Ohgushi, Kenya; Kawana, Daichi; Masuda, Takatsugu

    Inelastic neutron scattering experiment is performed on single crystals of multiferroics NdFe3(11BO3)4 to explore the magnetic excitations. Fe-centered dispersive excitation with the band width of 5 meV is observed along the crystallographic c∗ direction and that of 3 meV is along the a∗ direction. The energy gap of 0.57 meV due to an axial-type anisotropy is ob- served at the AF zone center. The energy of Nd-centered flat excitation is 1 meV. Furthermore, anticrossing of the Fe- and Nd-centered excitations is observed, meaning the existence of the f -d coupling, i.e., the interaction between the Nd3+ and Fe3+ moments. Spin-wave analysis on the observed neutron spectrum revealed the underlying magnetic Hamiltonian in NdFe3(11BO3)4. Discussion on the axial-type anisotropy in the ab - plane based on the magnetic model leads to the conclusion that the anisotropy of the Nd3+ ion plays a main role in the determination of the structures of both magnetic moment and electric polarization in NdFe3(BO3)4.

  7. Resonant inelastic x-ray scattering as a band structure probe of high-temperature superconductors

    NASA Astrophysics Data System (ADS)

    Kanasz-Nagy, Marton; Shi, Yifei; Klich, Israel; Demler, Eugene

    I will analyze recent resonant inelastic x-ray scattering (RIXS) experimental data on YBa2Cu3O6 + x [Minola et al., Phys. Rev. Lett. 114, 217003 (2015)] within quasi-particle theory. This measurement has been performed with the incoming photon energy detuned at several values from the resonance maximum, and, surprisingly, the data shows much weaker dependence on detuning than expected from recent measurements on a different cuprate superconductor, Bi2Sr2CuO6 + x [Guarise et al., Nat. Commun. 5, 5760 (2014)]. I will demonstrate, that this discrepancy, originally attributed to collective magnetic excitations, can be understood in terms of the differences between the band structures of these materials. We found good agreement between theory and experiment over a large range of dopings [M. Kanasz-Nagy et al., arXiv:1508.06639]. Moreover, I will demonstrate that the RIXS signal depends sensitively on excitations at energies well above the Fermi surface, that are inaccessible to traditionally used band structure probes, such as angle-resolved photoemission spectroscopy. This makes RIXS a powerful probe of band structure, not suffering from surface preparation problems and small sample sizes, making it potentially applicable to a wide range of materials. The work of M. K.-N. was supported by the Harvard-MIT CUA, NSF Grant No. DMR-1308435, AFOSR Quantum Simulation MURI, the ARO-MURI on Atomtronics, and ARO MURI Quism program.

  8. Nuclear resonant inelastic x-ray scattering: Methodology and extraction of vibrational properties of minerals

    NASA Astrophysics Data System (ADS)

    Hu, M. Y.; Alp, E. E.; Bi, W.; Sturhahn, W.; Toellner, T. S.; Zhao, J.

    2013-12-01

    Nuclear resonant inelastic x-ray scattering (NRIXS) is a synchrotron radiation based experimental method [1]. Since its introduction almost 20 years ago [2], NRIXS has found an expanding range of applications of studying lattice dynamics in condensed matter physics, materials science, high-pressure research, geosciences, and biophysics. After the first high pressure application in geophysics of measuring sound velocity of iron up to 153 GPa [3], it has become a widely used method to investigate deep earth compositions through sound velocity measurements [4,5]. Thermodynamic properties are also explored, in particular Grueneisen parameters [6]. Later, it was realized that isotope fractionaton factors can be derived from NRIXS measurements [7,8]. Sum rules and moments of NRIXS is a critical part of this methodology [9,10]. We will discuss this and in general the data analysis of NRIXS which enables the above mentioned applications. [1] Alp et al. Hyperfine Interactions 144/145, 3 (2002) [2] Sturhahn et al., PRL 74, 3832 (1995) [3] Mao et al., Science 292, 914 (2001) [4] Hu et al., PRB 67, 094304 (2003) [5] Sturhahn & Jackson, GSA special paper 421 (2007) [6] Murphy et al., Geophys. Res. Lett. 38, L24306 (2011) [7] Polyakov, Science 323, 912 (2009) [8] Dauphas et al., Geochimica et Cosmochimica Acta 94, 254 (2012) [9] Lipkin, PRB 52, 10073 (1995) [10] Hu et al., PRB 87, 064301 (2013)

  9. A new method to derive electronegativity from resonant inelastic x-ray scattering

    SciTech Connect

    Carniato, S.; Journel, L.; Guillemin, R.; Piancastelli, M. N.; Simon, M.; Stolte, W. C.; Lindle, D. W.

    2012-10-14

    Electronegativity is a well-known property of atoms and substituent groups. Because there is no direct way to measure it, establishing a useful scale for electronegativity often entails correlating it to another chemical parameter; a wide variety of methods have been proposed over the past 80 years to do just that. This work reports a new approach that connects electronegativity to a spectroscopic parameter derived from resonant inelastic x-ray scattering. The new method is demonstrated using a series of chlorine-containing compounds, focusing on the Cl 2p{sup -1}LUMO{sup 1} electronic states reached after Cl 1s{yields} LUMO core excitation and subsequent KL radiative decay. Based on an electron-density analysis of the LUMOs, the relative weights of the Cl 2p{sub z} atomic orbital contributing to the Cl 2p{sub 3/2} molecular spin-orbit components are shown to yield a linear electronegativity scale consistent with previous approaches.

  10. Structural and dynamical properties of chlorinated hydrocarbons studied with resonant inelastic x-ray scattering

    NASA Astrophysics Data System (ADS)

    Bohinc, R.; Žitnik, M.; Bučar, K.; Kavčič, M.; Carniato, S.; Journel, L.; Guillemin, R.; Marchenko, T.; Kawerk, E.; Simon, M.; Cao, W.

    2016-04-01

    We present a theoretical and experimental study of resonant inelastic x-ray scattering on a large group of chlorinated hydrocarbons: CH3Cl, CH2Cl2, CHCl3, CCl4, CH3CH2Cl, ClCH2CH2Cl, CH3CHCl2, CH3CCl3, C2H2Cl2-iso, C2H2Cl2-cis, C2H2Cl2-trans, and C6H5Cl. Differences in structural and dynamical properties of the molecules generated by diverse chemical environments are observed in the measured Cl(Kα) spectral maps as well as in the Cl(K) total fluorescence yield spectra. The energy position, relative intensity, and the width of the Franck-Condon distribution of low-lying σ∗ and π∗ resonances are extracted by a fitting procedure taking into account the experimental broadening. The theoretical values obtained with the transition potential and Δ Kohn-Sham methods are in good agreement with the experimental parameters indicating subtle differences due to variations in the molecular structure.

  11. Nuclear resonant inelastic X-ray scattering at high pressure and low temperature

    SciTech Connect

    Bi, Wenli; Zhao, Jiyong; Lin, Jung -Fu; Jia, Quanjie; Hu, Michael Y.; Jin, Changqing; Ferry, Richard; Yang, Wenge; Struzhkin, Viktor; Alp, E. Ercan

    2015-01-01

    In this study, a new synchrotron radiation experimental capability of coupling nuclear resonant inelastic X-ray scattering with the cryogenically cooled high-pressure diamond anvil cell technique is presented. The new technique permits measurements of phonon density of states at low temperature and high pressure simultaneously, and can be applied to studies of phonon contribution to pressure- and temperature-induced magnetic, superconducting and metal–insulator transitions in resonant isotope-bearing materials. In this report, a pnictide sample, EuFe2As2, is used as an example to demonstrate this new capability at beamline 3-ID of the Advanced Photon Source, Argonne National Laboratory. A detailed description of the technical development is given. The Fe-specific phonon density of states and magnetism from the Fe sublattice in Eu57Fe2As2 at high pressure and low temperature were derived by using this new capability.

  12. Rotationally inelastic scattering of OH by molecular hydrogen: Theory and experiment

    SciTech Connect

    Schewe, H. Christian Meijer, Gerard; Ma, Qianli; Dagdigian, Paul J.; Vanhaecke, Nicolas; Wang, Xingan; Kłos, Jacek; Alexander, Millard H.; Meerakker, Sebastiaan Y. T. van de; Avoird, Ad van der

    2015-05-28

    We present an experimental and theoretical investigation of rotationally inelastic transitions of OH, prepared in the X{sup 2}Π, v = 0, j = 3/2 F{sub 1}f level, in collisions with molecular hydrogen (H{sub 2} and D{sub 2}). In a crossed beam experiment, the OH radicals were state selected and velocity tuned over the collision energy range 75–155 cm{sup −1} using a Stark decelerator. Relative parity-resolved state-to-state integral cross sections were determined for collisions with normal and para converted H{sub 2}. These cross sections, as well as previous OH–H{sub 2} measurements at 595 cm{sup −1} collision energy by Schreel and ter Meulen [J. Chem. Phys. 105, 4522 (1996)], and OH–D{sub 2} measurements for collision energies 100–500 cm{sup −1} by Kirste et al. [Phys. Rev. A 82, 042717 (2010)], were compared with the results of quantum scattering calculations using recently determined ab initio potential energy surfaces [Ma et al., J. Chem. Phys. 141, 174309 (2014)]. Good agreement between the experimental and computed relative cross sections was found, although some structure seen in the OH(j = 3/2 F{sub 1}f → j = 5/2 F{sub 1}e) + H{sub 2}(j = 0) cross section is not understood.

  13. Spin observables in inelastic proton-nucleus scattering at intermediate energy

    SciTech Connect

    Smith, R.D.

    1984-01-01

    This dissertation is a study of spin observables in inelastic proton-nucleus reactions for incident proton energies near 1 GeV. At this energy, the dominant reaction mechanisms are (1) quasi-free knockout of one or more nucleons, and (2) pion production through the resonance. The cross section due to quasi-free knockout can be reasonably well understood theoretically in a multiple scattering picture, which uses measured NN amplitudes as input. Calculations of this sort were carried out in reference (10) using scalar NN amplitudes parameterized as Gaussians. The author has extended this picture to include spin dependent NN amplitudes. This allows calculation of all the spin observables, Ay, DLL, DSS, DNN, DLS, and DSL, as well as the cross section dsigma/dOmegadp due to quasi-free knockout of one or more particles. The cross section and polarization Ay have been measured at the LAMPF High Resolution Spectrometer at T/sub L/ = 800 MeV on SC. The theoretical results agree well with the data in the quasi-free region. The results for the remaining spin observables provide predictions for experiments which can be performed at LAMPF. By comparing the calculations with the data, it may be possible to separate the contribution due to a quasi-free knockout, and see a signature of quasi-free production in the spin observables.

  14. Cross sections for inelastic meson-meson scattering via quark-antiquark annihilation

    NASA Astrophysics Data System (ADS)

    Shen, Zhen-Yu; Xu, Xiao-Ming; Weber, H. J.

    2016-08-01

    We study inelastic meson-meson scattering that is governed by quark-antiquark annihilation and creation involving a quark and an antiquark annihilating into a gluon, and subsequently the gluon creating another quark-antiquark pair. The resultant hadronic reactions include for I =1 : π π →ρ ρ , K K ¯→K*K¯*, K K¯*→K*K¯*, K*K ¯→K*K¯*, as well as π π →K K ¯, π ρ →K K¯*, π ρ →K*K ¯, and K K ¯→ρ ρ . In each reaction, one or two Feynman diagrams are involved in the Born approximation. We derive formulas for the unpolarized cross section, the transition amplitude, and the transition potential for quark-antiquark annihilation and creation. The unpolarized cross sections for the reactions are calculated at six temperatures, and prominent temperature dependence is found. It is due to differences among mesonic temperature dependence in hadronic matter.

  15. Raman and fluorescence characteristics of resonant inelastic X-ray scattering from doped superconducting cuprates

    DOE PAGESBeta

    Huang, H. Y.; Jia, C. J.; Chen, Z. Y.; Wohlfeld, K.; Moritz, B.; Devereaux, T. P.; Wu, W. B.; Okamoto, J.; Lee, W. S.; Hashimoto, M.; et al

    2016-01-22

    Measurements of spin excitations are essential for an understanding of spin-mediated pairing for superconductivity; and resonant inelastic X-ray scattering (RIXS) provides a considerable opportunity to probe high-energy spin excitations. However, whether RIXS correctly measures the collective spin excitations of doped superconducting cuprates remains under debate. Here we demonstrate distinct Raman- and fluorescence-like RIXS excitations of Bi1.5Pb0.6Sr1.54CaCu2O8+δ. Combining photon-energy and momentum dependent RIXS measurements with theoretical calculations using exact diagonalization provides conclusive evidence that the Raman-like RIXS excitations correspond to collective spin excitations, which are magnons in the undoped Mott insulators and evolve into paramagnons in doped superconducting compounds. In contrast,more » the fluorescence-like shifts are due primarily to the continuum of particle-hole excitations in the charge channel. Our results show that under the proper experimental conditions RIXS indeed can be used to probe paramagnons in doped high-Tc cuprate superconductors.« less

  16. Rotationally inelastic scattering of OH by molecular hydrogen: Theory and experiment

    NASA Astrophysics Data System (ADS)

    Schewe, H. Christian; Ma, Qianli; Vanhaecke, Nicolas; Wang, Xingan; Kłos, Jacek; Alexander, Millard H.; van de Meerakker, Sebastiaan Y. T.; Meijer, Gerard; van der Avoird, Ad; Dagdigian, Paul J.

    2015-05-01

    We present an experimental and theoretical investigation of rotationally inelastic transitions of OH, prepared in the X2Π, v = 0, j = 3/2 F1f level, in collisions with molecular hydrogen (H2 and D2). In a crossed beam experiment, the OH radicals were state selected and velocity tuned over the collision energy range 75-155 cm-1 using a Stark decelerator. Relative parity-resolved state-to-state integral cross sections were determined for collisions with normal and para converted H2. These cross sections, as well as previous OH-H2 measurements at 595 cm-1 collision energy by Schreel and ter Meulen [J. Chem. Phys. 105, 4522 (1996)], and OH-D2 measurements for collision energies 100-500 cm-1 by Kirste et al. [Phys. Rev. A 82, 042717 (2010)], were compared with the results of quantum scattering calculations using recently determined ab initio potential energy surfaces [Ma et al., J. Chem. Phys. 141, 174309 (2014)]. Good agreement between the experimental and computed relative cross sections was found, although some structure seen in the OH(j = 3/2 F1f → j = 5/2 F1e) + H2(j = 0) cross section is not understood.

  17. Rotationally inelastic scattering of OH by molecular hydrogen: Theory and experiment.

    PubMed

    Schewe, H Christian; Ma, Qianli; Vanhaecke, Nicolas; Wang, Xingan; Kłos, Jacek; Alexander, Millard H; van de Meerakker, Sebastiaan Y T; Meijer, Gerard; van der Avoird, Ad; Dagdigian, Paul J

    2015-05-28

    We present an experimental and theoretical investigation of rotationally inelastic transitions of OH, prepared in the X(2)Π, v = 0, j = 3/2 F1f level, in collisions with molecular hydrogen (H2 and D2). In a crossed beam experiment, the OH radicals were state selected and velocity tuned over the collision energy range 75-155 cm(-1) using a Stark decelerator. Relative parity-resolved state-to-state integral cross sections were determined for collisions with normal and para converted H2. These cross sections, as well as previous OH-H2 measurements at 595 cm(-1) collision energy by Schreel and ter Meulen [J. Chem. Phys. 105, 4522 (1996)], and OH-D2 measurements for collision energies 100-500 cm(-1) by Kirste et al. [Phys. Rev. A 82, 042717 (2010)], were compared with the results of quantum scattering calculations using recently determined ab initio potential energy surfaces [Ma et al., J. Chem. Phys. 141, 174309 (2014)]. Good agreement between the experimental and computed relative cross sections was found, although some structure seen in the OH(j = 3/2 F1f → j = 5/2 F1e) + H2(j = 0) cross section is not understood. PMID:26026450

  18. Incident-energy-dependent spectral weight of resonant inelastic x-ray scattering in doped cuprates

    NASA Astrophysics Data System (ADS)

    Tsutsui, Kenji; Tohyama, Takami

    2016-08-01

    We theoretically investigate the incident-photon energy ωi dependence of resonant inelastic x-ray scattering (RIXS) tuned for the Cu L edge in cuprate superconductors by using the exact diagonalization technique for a single-band Hubbard model. Depending on the value of core-hole Coulomb interaction in the intermediate state, RIXS for non-spin-flip channel shows either a ωi-dependent fluorescencelike or ωi-independent Raman-like behavior for hole doping. An analysis of x-ray absorption suggests that the core-hole Coulomb interaction is larger than on-site Coulomb interaction in the Hubbard model, resulting in a fluorescencelike behavior in RIXS consistent with recent RIXS experiments. A shift on the high-energy side of the center of spectral distribution is also predicted for electron-doped systems though spectral weight is small. Main structures in the spin-flip channel exhibit a Raman-like behavior as expected, accompanied with a fluorescencelike behavior with small intensity.

  19. Inelastic Scattering of CO with He: Polarization Dependent Differential State-to-State Cross Sections.

    PubMed

    Song, Lei; Groenenboom, Gerrit C; van der Avoird, Ad; Bishwakarma, Chandan Kumar; Sarma, Gautam; Parker, David H; Suits, Arthur G

    2015-12-17

    A joint theoretical and experimental study of state-to-state rotationally inelastic polarization dependent differential cross sections (PDDCSs) for CO (v = 0, j = 0, 1, 2) molecules colliding with helium is reported for collision energies of 513 and 840 cm(-1). In a crossed molecular beam experiment, velocity map imaging (VMI) with state-selective detection by (2 + 1) and (1 + 1') resonance enhanced multiphoton ionization (REMPI) is used to probe rotational excitation of CO due to scattering. By taking account of the known fractions of the j = 0, 1, and 2 states of CO in the rotationally cold molecular beam (Trot ≈ 3 K), close-coupling theory based on high-quality ab initio potential energy surfaces for the CO-He interaction is used to simulate the differential cross sections for the mixed initial states. With polarization-sensitive 1 + 1' REMPI detection and a direct analysis procedure described by Suits et al. ( J. Phys, Chem. A 2015 , 119 , 5925 ), alignment moments are extracted from the images and the latter are compared with images simulated by theory using the calculated DCS and alignment moments. In general, good agreement of theory with the experimental results is found, indicating the reliability of the experiment in reproducing state-to-state differential and polarization-dependent differential cross sections. PMID:26473516

  20. DATA REVIEW: A compilation of structure functions in deep inelastic scattering

    NASA Astrophysics Data System (ADS)

    Gehrmann, T.; Roberts, R. G.; Whalley, M. R.

    1999-12-01

    A compilation of all the available data on the unpolarized structure functions F2 and xF3, R = (icons/Journals/Common/sigma" ALT="sigma" ALIGN="TOP"/>L/icons/Journals/Common/sigma" ALT="sigma" ALIGN="TOP"/>T), the virtual photon asymmetries A1 and A2 and the polarized structure functions g1 and g2, from deep inelastic lepton scattering off protons, deuterium and nuclei is presented. The relevant experiments at CERN, DESY, Fermilab and SLAC from 1991, the date of our earlier review [1], to the present day are covered. A brief general theoretical introduction is given followed by the data presented both in tabular and graphical form and, for the F2 and xF3 data, the predictions based on the MRST98 and CTEQ4 parton distribution functions are also displayed. All the data in this review, together with data on a wide variety of other reactions, can be found in and retrieved from the Durham-RAL HEP Databases on the World-Wide-Web (http://durpdg.dur.ac.uk/HEPDATA)

  1. Excitations in a thin liquid {sup 4}He film from inelastic neutron scattering

    SciTech Connect

    Clements, B.E. |; Godfrin, H.; Krotscheck, E. |; Lauter, H.J.; Leiderer, P.; Passiouk, V. |; Tymczak, C.J.

    1996-05-01

    We perform a thorough analysis of the experimental dynamic structure function measured by inelastic neutron scattering for a low-temperature ({ital T}=0.65 K) four-layer liquid {sup 4}He film. The results are interpreted in light of recent theoretical calculations of the (nonvortex) excitations in thin liquid Bose films. The experimental system consists of four outer liquid layers, adsorbed to two solid inner {sup 4}He layers, which are themselves adsorbed to a graphite substrate. Relatively intense surface (ripplon) and bulklike modes are observed. The analysis of the experimental data gives strong evidence for still other modes and supports the long-standing theoretical predictions of layerlike modes (layer phonons) associated with excitations propagating primarily within the liquid layers comprising the film. The results of the analysis are consistent with the occurrence of level crossings between modes, and the existence of a layer modes for which the theory predicts will propagate in the vicinity of the solid-liquid interface. The theory and experiment agree on the detailed nature of the ripplon; its dispersion at low momenta, its fall off in intensity at intermediate momenta, and the level crossings at high momentum. Similar to experiment, the theory yields an intense mode in the maxon-roton region which is intrepreted as the formation of the bulklike excitation. {copyright} {ital 1996 The American Physical Society.}

  2. Crystal electric field excitations in quasicrystal approximant TbCd6 studied by inelastic neutron scattering

    NASA Astrophysics Data System (ADS)

    Das, Pinaki; Flint, R.; Kong, T.; Canfield, P. C.; Kreyssig, A.; Goldman, A. I.; de Boissieu, M.; Lory, P.-F.; Beutier, G.; Hiroto, T.

    All of the known quasicrystals with local moments exhibit frustration and spin glass-like behavior at low temperature. The onset of the spin freezing temperature is believed to be affected by the crystal electric field (CEF) splitting of the local moments. The quasicrystal approximant TbCd6 and its related icosahedral quasicrystal phase, i-Tb-Cd, form a set of model systems to explore how magnetism evolves from a conventional lattice (approximant phase) to an aperiodic quasicrystal. Though TbCd6 shows long-range antiferromagnetic ordering (TN = 24 K), only spin glass like behavior is observed in i-Tb-Cd with a spin freezing temperature of TF = 6 K. To investigate further, we have performed inelastic neutron scattering measurements on powder samples of TbCd6 and observed two distinct CEF excitations at low energies which points to a high degeneracy of the CEF levels related to the Tb surrounding with almost icosahedral symmetry. Work at Ames Laboratory was supported by the DOE, BES, Division of Materials Sciences & Engineering, under Contract No. DE-AC02-07CH11358. This research used resources at Institut Laue-Langevin, France.

  3. Collective dynamics of hydrated β-lactoglobulin by inelastic x-ray scattering.

    PubMed

    Yoshida, Koji; Hosokawa, Shinya; Baron, Alfred Q R; Yamaguchi, Toshio

    2010-10-01

    Inelastic x-ray scattering measurements of hydrated β-lactoglobulin (β-lg) were performed to investigate the collective dynamics of hydration water and hydrated protein on a picosecond time scale. Samples with different hydration levels h [=mass of water (g)/mass of protein (g)] of 0 (dry), 0.5, and 1.0 were measured at ambient temperature. The observed dynamical structure factor S(Q,ω)/S(Q) was analyzed by a model composed of a Lorentzian for the central peak and a damped harmonic oscillator (DHO) for the side peak. The dispersion relation between the excitation energy in the DHO model and the momentum transfer Q was obtained for the hydrated β-lg at both hydration levels, but no DHO excitation was found for the dry β-lg. The high-frequency sound velocity was similar to that previously observed in pure water. The ratio of the high-frequency sound velocity of hydrated β-lg to the adiabatic one of hydrated lysozyme (h=0.41) was estimated as ∼1.6 for h=0.5. The value is significantly smaller than that (∼2) of pure water that has the tetrahedral network structure. The present finding thus suggests that the tetrahedral network structure of water around the β-lg is partially disrupted by the perturbation from protein surface. These results are consistent with those reported from Brillouin neutron spectroscopy and molecular dynamics simulation studies of hydrated ribonuclease A. PMID:20942540

  4. Molecular Orbital Simulations of Metal 1s2p Resonant Inelastic X-ray Scattering.

    PubMed

    Guo, Meiyuan; Källman, Erik; Sørensen, Lasse Kragh; Delcey, Mickaël G; Pinjari, Rahul V; Lundberg, Marcus

    2016-07-28

    For first-row transition metals, high-resolution 3d electronic structure information can be obtained using resonant inelastic X-ray scattering (RIXS). In the hard X-ray region, a K pre-edge (1s→3d) excitation can be followed by monitoring the dipole-allowed Kα (2p→1s) or Kβ (3p→1s) emission, processes labeled 1s2p or 1s3p RIXS. Here the restricted active space (RAS) approach, which is a molecular orbital method, is used for the first time to study hard X-ray RIXS processes. This is achieved by including the two sets of core orbitals in different partitions of the active space. Transition intensities are calculated using both first- and second-order expansions of the wave vector, including, but not limited to, electric dipoles and quadrupoles. The accuracy of the approach is tested for 1s2p RIXS of iron hexacyanides [Fe(CN)6](n-) in ferrous and ferric oxidation states. RAS simulations accurately describe the multiplet structures and the role of 2p and 3d spin-orbit coupling on energies and selection rules. Compared to experiment, relative energies of the two [Fe(CN)6](3-) resonances deviate by 0.2 eV in both incident energy and energy transfer directions, and multiplet splittings in [Fe(CN)6](4-) are reproduced within 0.1 eV. These values are similar to what can be expected for valence excitations. The development opens the modeling of hard X-ray scattering processes for both solution catalysts and enzymatic systems. PMID:27398775

  5. Simulation of inelastic-scattering contributions to the irradiance field in the ocean: variation in Fraunhofer line depths.

    PubMed

    Ge, Y; Gordon, H R; Voss, K J

    1993-07-20

    Raman scattering and fluorescence are important processes in oceanic optics because of their influence on the natural light field in the water. Monte Carlo simulations are described that verify that measurements of the Fraunhofer line depth in the in-water irradiance can be used to separate the irradiance into elastic and inelastic components, i.e., components that are generated by elastic- and inelastic-scattering processes, respectively. Specifically, the upwelling and downwelling irradiances, including Raman scattering, are simulated for a variety of model oceans. The inherent optical properties of the ocean are derived from a bio-optical model in which the elastic-scattering and the absorption coefficients of the biological material depend only on the phytoplankton pigment concentration, C. The Fraunhofer line at 656 nm is found to fill in, i.e., disappear into, the background continuum rapidly with increasing depth. This indicates a rapid transition from a near-surface light field dominated by elastic s cattering to one composed of irradiance derived entirely from Raman scattering. Conversely the depth of the Fraunhofer line at 486 mm is nearly independent of depth in the water, indicating that Raman scattering never makes a significant contribution to the irradiance there. Between these two extremes, the lines at 518 and 589 nm show variations in line depths that depend significantly on C, e.g., at 518 nm the line fills in with increasing depth at low-C values but not at high-C values.

  6. Measurement of the structure function of the nearly free neutron using spectator tagging in inelastic 2H(e ,e'ps )X scattering with CLAS

    NASA Astrophysics Data System (ADS)

    Tkachenko, S.; Baillie, N.; Kuhn, S. E.; Zhang, J.; Arrington, J.; Bosted, P.; Bültmann, S.; Christy, M. E.; Fenker, H.; Griffioen, K. A.; Kalantarians, N.; Keppel, C. E.; Melnitchouk, W.; Tvaskis, V.; Adhikari, K. P.; Aghasyan, M.; Amaryan, M. J.; Anefalos Pereira, S.; Avakian, H.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A. S.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Cole, P. L.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dodge, G. E.; Doughty, D.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fleming, J. A.; Garillon, B.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Golovatch, E.; Gothe, R. W.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Hicks, K.; Ho, D.; Holtrop, M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Jo, H. S.; Keller, D.; Khandaker, M.; Kim, A.; Kim, W.; King, P. M.; Klein, A.; Klein, F. J.; Koirala, S.; Kubarovsky, V.; Kuleshov, S. V.; Lenisa, P.; Lewis, S.; Livingston, K.; Lu, H.; MacCormick, M.; MacGregor, I. J. D.; Markov, N.; Mayer, M.; McKinnon, B.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Moutarde, H.; Munoz Camacho, C.; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Pappalardo, L. L.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Phillips, J. J.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Protopopescu, D.; Puckett, A. J. R.; Rimal, D.; Ripani, M.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Schott, D.; Schumacher, R. A.; Seder, E.; Senderovich, I.; Sharabian, Y. G.; Simonyan, A.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Stepanyan, S.; Stepanyan, S. S.; Strauch, S.; Tang, W.; Ungaro, M.; Vlassov, A. V.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D.; Wei, X.; Weinstein, L. B.; Wood, M. H.; Zana, L.; Zonta, I.; CLAS Collaboration

    2014-04-01

    Background: Much less is known about neutron structure than that of the proton due to the absence of free neutron targets. Neutron information is usually extracted from data on nuclear targets such as deuterium, requiring corrections for nuclear binding and nucleon off-shell effects. These corrections are model dependent and have significant uncertainties, especially for large values of the Bjorken scaling variable x . As a consequence, the same data can lead to different conclusions, for example, about the behavior of the d quark distribution in the proton at large x . Purpose: The Barely Off-shell Nucleon Structure experiment at Jefferson Lab measured the inelastic electron-deuteron scattering cross section, tagging spectator protons in coincidence with the scattered electrons. This method reduces nuclear binding uncertainties significantly and has allowed for the first time a (nearly) model-independent extraction of the neutron structure function F2(x ,Q2) in the resonance and deep-inelastic regions. Method: A novel compact radial time projection chamber was built to detect protons with momentum between 70 and 150 MeV/c and over a nearly 4 π angular range. For the extraction of the free-neutron structure function F2n, spectator protons at backward angles (>100∘ relative to the momentum transfer) and with momenta below 100 MeV/c were selected, ensuring that the scattering took place on a nearly free neutron. The scattered electrons were detected with Jefferson Lab's CLAS spectrometer, with data taken at beam energies near 2, 4, and 5 GeV. Results: The extracted neutron structure function F2n and its ratio to the inclusive deuteron structure function F2d are presented in both the resonance and the deep-inelastic regions for momentum transfer squared Q2 between 0.7 and 5 GeV2/c2 , invariant mass W between 1 and 2.7 GeV/c2 , and Bjorken x between 0.25 and 0.6 (in the deep-inelastic scattering region). The dependence of the semi-inclusive cross section on the

  7. Charm-Quark Production in Deep-Inelastic Neutrino Scattering at Next-to-Next-to-Leading Order in QCD.

    PubMed

    Berger, Edmond L; Gao, Jun; Li, Chong Sheng; Liu, Ze Long; Zhu, Hua Xing

    2016-05-27

    We present a fully differential next-to-next-to-leading order calculation of charm-quark production in charged-current deep-inelastic scattering, with full charm-quark mass dependence. The next-to-next-to-leading order corrections in perturbative quantum chromodynamics are found to be comparable in size to the next-to-leading order corrections in certain kinematic regions. We compare our predictions with data on dimuon production in (anti)neutrino scattering from a heavy nucleus. Our results can be used to improve the extraction of the parton distribution function of a strange quark in the nucleon.

  8. Demonstrating Photoluminescence from Au is Electronic Inelastic Light Scattering of a Plasmonic Metal: The Origin of SERS Backgrounds

    PubMed Central

    2015-01-01

    Temperature-dependent surface-enhanced Raman scattering (SERS) is used to investigate the photoluminescence and background continuum always present in SERS but whose origin remains controversial. Both the Stokes and anti-Stokes background is found to be dominated by inelastic light scattering (ILS) from the electrons in the noble metal nanostructures supporting the plasmon modes. The anti-Stokes background is highly temperature dependent and is shown to be related to the thermal occupation of electronic states within the metal via a simple model. This suggests new routes to enhance SERS sensitivities, as well as providing ubiquitous and calibrated real-time temperature measurements of nanostructures. PMID:25734469

  9. Charm-Quark Production in Deep-Inelastic Neutrino Scattering at Next-to-Next-to-Leading Order in QCD.

    PubMed

    Berger, Edmond L; Gao, Jun; Li, Chong Sheng; Liu, Ze Long; Zhu, Hua Xing

    2016-05-27

    We present a fully differential next-to-next-to-leading order calculation of charm-quark production in charged-current deep-inelastic scattering, with full charm-quark mass dependence. The next-to-next-to-leading order corrections in perturbative quantum chromodynamics are found to be comparable in size to the next-to-leading order corrections in certain kinematic regions. We compare our predictions with data on dimuon production in (anti)neutrino scattering from a heavy nucleus. Our results can be used to improve the extraction of the parton distribution function of a strange quark in the nucleon. PMID:27284650

  10. Distributions of charged hadrons observed in deep-inelastic muon-deuterium scattering at 490 GeV

    NASA Astrophysics Data System (ADS)

    Adams, M. R.; Aïd, S.; Anthony, P. L.; Baker, M. D.; Bartlett, J.; Bhatti, A. A.; Braun, H. M.; Busza, W.; Conrad, J. M.; Coutrakon, G.; Davisson, R.; Derado, I.; Dhawan, S. K.; Dougherty, W.; Dreyer, T.; Dziunikowska, K.; Eckardt, V.; Ecker, U.; Erdmann, M.; Eskreys, A.; Figiel, J.; Gebauer, H. J.; Geesaman, D. F.; Gilman, R.; Green, M. C.; Haas, J.; Halliwell, C.; Hanlon, J.; Hantke, D.; Hughes, V. W.; Jackson, H. E.; Jaffe, D. E.; Jancso, G.; Jansen, D. M.; Kaufman, S.; Kennedy, R. D.; Kirk, T.; Kobrak, H. G. E.; Krzywdzinski, S.; Kunori, S.; Lord, J. J.; Lubatti, H. J.; McLeod, D.; Magill, S.; Malecki, P.; Manz, A.; Melanson, H.; Michael, D. G.; Mohr, W.; Montgomery, H. E.; Morfin, J. G.; Nickerson, R. B.; O'Day, S.; Olkiewicz, K.; Osborne, L.; Papavassiliou, V.; Pawlik, B.; Pipkin, F. M.; Ramberg, E. J.; Röser, A.; Ryan, J. J.; Salvarani, A.; Schellman, H.; Schmitt, M.; Schmitz, N.; Schüler, K. P.; Seyerlein, H. J.; Skuja, A.; Snow, G. A.; Söldner-Rembold, S.; Steinberg, P. H.; Stier, H. E.; Stopa, P.; Swanson, R. A.; Talaga, R.; Tentindo-Repond, S.; Trost, H.-J.; Vidal, M.; Wilhelm, M.; Wilkes, J.; Venkataramania, H.; Wilson, Richard; Wittek, W.; Wolbers, S. A.; Zhao, T.

    1991-11-01

    Longitudinal and transverse momentum spectra of final state hadrons produced in deep-inelastic muon-deuterium scattering at incident muon energy of 490 GeV have been measured up to a hadronic center of mass energy of 30 GeV. The longitudinal distributions agree well with data from earlier muon-nucleon scattering experiments; these distributions tend to increase in steepness as the center of mass energy increases. Comparisons with e+e- data at comparable center of mass energies indicate slight differences. The transverse momentum distributions show an increase in mean pT2 with an increase in the center of mass energy.

  11. Diffractive dijet production in deep inelastic scattering and photon-hadron collisions in the color glass condensate

    NASA Astrophysics Data System (ADS)

    Altinoluk, Tolga; Armesto, Néstor; Beuf, Guillaume; Rezaeian, Amir H.

    2016-07-01

    We study exclusive dijet production in coherent diffractive processes in deep inelastic scattering and real (and virtual) photon-hadron (γ (*)-h) collisions in the Color Glass Condensate formalism at leading order. We show that the diffractive dijet cross section is sensitive to the color-dipole orientation in the transverse plane, and is a good probe of possible correlations between the q q bar -dipole transverse separation vector r and the dipole impact parameter b. We also investigate the diffractive dijet azimuthal angle correlations and t-distributions in γ (*)-h collisions and show that they are sensitive to gluon saturation effects in the small-x region. In particular, we show that the t-distribution of diffractive dijet photo-production off a proton target exhibits a dip-type structure in the saturation region. This effect is similar to diffractive vector meson production. Besides, at variance with the inclusive case, the effect of saturation leads to stronger azimuthal correlations between the jets.

  12. A new self-filling mechanism of band gap in magnetically doped topological surface states: spin-flipping inelastic scattering

    NASA Astrophysics Data System (ADS)

    Wang, Rui-Qiang; Zheng, Shi-Han; Yang, Mou

    2016-09-01

    We investigate the influence of in-plane spin-exchange interactions on a topological insulator (TI) surface doped with nanomagnets under the second perturbation theory. We propose a novel self-filling mechanism of the surface-state band gap. It is found that when the out-of-plane exchange coupling favors an energy gap around the Dirac point, the in-plane component tends to suppress the induced gap, and even fill it completely. Our theory is based on the spin-flipping inelastic scattering, which creates a complex structure of self-energy, effectively modifying the band gap by renormalizing the magnetic moment and chemical potential. We explicitly analyze the filling effect in the electronic dispersion relation and density of states for different scenarios set by systemic parameters. This self-filling effect induced by spin-exchange coupling itself opens new perspectives for understanding of various magnetically doping phenomena on the TI materials and is expected to mediate the controversy concerning the magnetically doping induced gap.

  13. Quantum State-Resolved Reactive and Inelastic Scattering at Gas-Liquid and Gas-Solid Interfaces

    NASA Astrophysics Data System (ADS)

    Grütter, Monika; Nelson, Daniel J.; Nesbitt, David J.

    2012-06-01

    Quantum state-resolved reactive and inelastic scattering at gas-liquid and gas-solid interfaces has become a research field of considerable interest in recent years. The collision and reaction dynamics of internally cold gas beams from liquid or solid surfaces is governed by two main processes, impulsive scattering (IS), where the incident particles scatter in a few-collisions environment from the surface, and trapping-desorption (TD), where full equilibration to the surface temperature (T{TD}≈ T{s}) occurs prior to the particles' return to the gas phase. Impulsive scattering events, on the other hand, result in significant rotational, and to a lesser extent vibrational, excitation of the scattered molecules, which can be well-described by a Boltzmann-distribution at a temperature (T{IS}>>T{s}). The quantum-state resolved detection used here allows the disentanglement of the rotational, vibrational, and translational degrees of freedom of the scattered molecules. The two examples discussed are (i) reactive scattering of monoatomic fluorine from room-temperature ionic liquids (RTILs) and (ii) inelastic scattering of benzene from a heated (˜500 K) gold surface. In the former experiment, rovibrational states of the nascent HF beam are detected using direct infrared absorption spectroscopy, and in the latter, a resonace-enhanced multi-photon-ionization (REMPI) scheme is employed in combination with a velocity-map imaging (VMI) device, which allows the detection of different vibrational states of benzene excited during the scattering process. M. E. Saecker, S. T. Govoni, D. V. Kowalski, M. E. King and G. M. Nathanson Science 252, 1421, 1991. A. M. Zolot, W. W. Harper, B. G. Perkins, P. J. Dagdigian and D. J. Nesbitt J. Chem. Phys 125, 021101, 2006. J. R. Roscioli and D. J. Nesbitt Faraday Disc. 150, 471, 2011.

  14. Magnetic Transitions in Iron Porphyrin Halides by Inelastic Neutron Scattering and Ab Initio Studies of Zero-Field Splittings.

    PubMed

    Stavretis, Shelby E; Atanasov, Mihail; Podlesnyak, Andrey A; Hunter, Seth C; Neese, Frank; Xue, Zi-Ling

    2015-10-19

    Zero-field splitting (ZFS) parameters of nondeuterated metalloporphyrins [Fe(TPP)X] (X = F, Br, I; H₂TPP = tetraphenylporphyrin) have been directly determined by inelastic neutron scattering (INS). The ZFS values are D = 4.49(9) cm⁻¹ for tetragonal polycrystalline [Fe(TPP)F], and D = 8.8(2) cm⁻¹, E = 0.1(2) cm⁻¹ and D = 13.4(6) cm⁻¹, E = 0.3(6) cm⁻¹ for monoclinic polycrystalline [Fe(TPP)Br] and [Fe(TPP)I], respectively. Along with our recent report of the ZFS value of D = 6.33(8) cm⁻¹ for tetragonal polycrystalline [Fe(TPP)Cl], these data provide a rare, complete determination of ZFS parameters in a metalloporphyrin halide series. The electronic structure of [Fe(TPP)X] (X = F, Cl, Br, I) has been studied by multireference ab initio methods: the complete active space self-consistent field (CASSCF) and the N-electron valence perturbation theory (NEVPT2) with the aim of exploring the origin of the large and positive zero-field splitting D of the ⁶A₁ ground state. D was calculated from wave functions of the electronic multiplets spanned by the d⁵ configuration of Fe(III) along with spin–orbit coupling accounted for by quasi degenerate perturbation theory. Results reproduce trends of D from inelastic neutron scattering data increasing in the order from F, Cl, Br, to I. A mapping of energy eigenvalues and eigenfunctions of the S = 3/2 excited states on ligand field theory was used to characterize the σ- and π-antibonding effects decreasing from F to I. This is in agreement with similar results deduced from ab initio calculations on CrX₆³⁻ complexes and also with the spectrochemical series showing a decrease of the ligand field in the same directions. A correlation is found between the increase of D and decrease of the π- and σ-antibonding energies e(λ)(X) (λ = σ, π) in the series from X = F to I. Analysis of this correlation using second-order perturbation theory expressions in terms of angular overlap parameters rationalizes the

  15. Magnetic Transitions in Iron Porphyrin Halides by Inelastic Neutron Scattering and Ab-initio Studies of Zero-Field Splittings

    DOE PAGESBeta

    Stavretis, Shelby E.; Atanasov, Mihail; Podlesnyak, Andrey A.; Hunter, Seth C.; Neese, Frank; Xue, Zi-Ling

    2015-10-02

    Zero-field splitting (ZFS) parameters of nondeuterated metalloporphyrins [Fe(TPP)X] (X = F, Br, I; H2TPP = tetraphenylporphyrin) are determined by inelastic neutron scattering (INS). The ZFS values are D = 4.49(9) cm–1 for tetragonal polycrystalline [Fe(TPP)F], and D = 8.8(2) cm–1, E = 0.1(2) cm–1 and D = 13.4(6) cm–1, E = 0.3(6) cm–1 for monoclinic polycrystalline [Fe(TPP)Br] and [Fe(TPP)I], respectively. Along with our recent report of the ZFS value of D = 6.33(8) cm–1 for tetragonal polycrystalline [Fe(TPP)Cl], these data provide a rare, complete determination of ZFS parameters in a metalloporphyrin halide series. The electronic structure of [Fe(TPP)X] (X =more » F, Cl, Br, I) has been studied by multireference ab initio methods: the complete active space self-consistent field (CASSCF) and the N-electron valence perturbation theory (NEVPT2) with the aim of exploring the origin of the large and positive zero-field splitting D of the 6A1 ground state. D was calculated from wave functions of the electronic multiplets spanned by the d5 configuration of Fe(III) along with spin–orbit coupling accounted for by quasi degenerate perturbation theory. Results reproduce trends of D from inelastic neutron scattering data increasing in the order from F, Cl, Br, to I. A mapping of energy eigenvalues and eigenfunctions of the S = 3/2 excited states on ligand field theory was used to characterize the σ- and π-antibonding effects decreasing from F to I. This is in agreement with similar results deduced from ab initio calculations on CrX63- complexes and also with the spectrochemical series showing a decrease of the ligand field in the same directions. A correlation is found between the increase of D and decrease of the π- and σ-antibonding energies eλX (λ = σ, π) in the series from X = F to I. Analysis of this correlation using second-order perturbation theory expressions in terms of angular overlap parameters rationalizes the experimentally deduced trend

  16. Search for a reliable nucleic acid force field using neutron inelastic scattering and quantum mechanical calculations: Bases, nucleosides and nucleotides

    SciTech Connect

    Leulliot, Nicolas; Ghomi, Mahmoud; Jobic, Herve

    1999-06-15

    Neutron inelastic scattering (NIS), IR and Raman spectra of the RNA constituents: bases, nucleosides and nucleotides have been analyzed. The complementary aspects of these different experimental techniques makes them especially powerful for assigning the vibrational modes of the molecules of interest. Geometry optimization and harmonic force field calculations of these molecules have been undertaken by quantum mechanical calculations at several theoretical levels: Hartree-Fock (HF), Moller-plesset second-order perturbation (MP2) and Density Functional Theory (DFT). In all cases, it has been shown that HF calculations lead to insufficient results for assigning accurately the intramolecular vibrational modes. In the case of the nucleic bases, these discrepancies could be satisfactorily removed by introducing the correlation effects at MP2 level. However, the application of the MP2 procedure to the large size molecules such as nucleosides and nucleotides is absolutely impossible, taking into account the prohibitive computational time needed. On the basis of our results, the calculations at DFT levels using B3LYP exchange and correlation functional appear to be a cost-effective alternative in obtaining a reliable force field for the whole set of nucleic acid constituents.

  17. Naive time-reversal odd phenomena in semi-inclusive deep-inelastic scattering from light-cone constituent quark models

    SciTech Connect

    Barbara Pasquini, Peter Schweitzer

    2011-06-01

    We present results for leading-twist azimuthal asymmetries in semi-inclusive lepton-nucleon deep-inelastic scattering due to naively time-reversal odd transverse-momentum dependent parton distribution functions from the light-cone constituent quark model. We carefully discuss the range of applicability of the model, especially with regard to positivity constraints and evolution effects. We find good agreement with available experimental data from COMPASS and HERMES, and present predictions to be tested in forthcoming experiments at Jefferson Lab.

  18. Inelastic deformation and phenomenological modeling of aluminum including transient effect

    SciTech Connect

    Cho, C.W.

    1980-01-01

    A review was made of several phenomenological theories which have recently been proposed to describe the inelastic deformation of crystalline solids. Hart's deformation theory has many advantages, but there are disagreements with experimental deformation at stress levels below yield. A new inelastic deformation theory was proposed, introducing the concept of microplasticity. The new model consists of five deformation elements: a friction element representing a deformation element controlled by dislocation glide, a nonrecoverable plastic element representing the dislocation leakage rate over the strong dislocation barriers, a microplastic element representing the dislocation leakage rate over the weak barriers, a short range anelastic spring element representing the recoverable anelastic strain stored by piled-up dislocations against the weak barriers, and a long range anelastic spring element representing the recoverable strain stored by piled-up dislocations against the strong barriers. Load relaxation and tensile testing in the plastic range were used to determine the material parameters for the plastic friction elements. The short range and long range anelastic moduli and the material parameters for the kinetics of microplasticity were determined by the measurement of anelastic loops and by performing load relaxation tests in the microplastic region. Experimental results were compared with a computer simulation of the transient deformation behavior of commercial purity aluminum. An attempt was made to correlate the material parameters and the microstructure from TEM. Stability of material parameters during inelastic deformation was discussed and effect of metallurgical variables was examined experimentally. 71 figures, 5 tables.

  19. Techniques for inelastic x-ray scattering with {mu}eV resolution.

    SciTech Connect

    Rohlsberger, R.

    1998-10-23

    We introduce a novel type of spectrometer that provides a {micro}eV bandpass together with a tunability over a few meV. The technique relies on nuclear resonant scattering (Moessbauer effect) of synchrotrons radiation at the 14.4-keV resonance of {sup 57}Fe. Energy tuning is achieved by the Doppler effect in high speed rotary motion. The resonantly scattered monochromatic radiation is extracted by a polarization filtering technique or by spatial separation due to the ''nuclear lighthouse effect''.

  20. Transverse Target Moments of Dihadron Production in Semi-inclusive Deep Inelastic Scattering at HERMES

    NASA Astrophysics Data System (ADS)

    Gliske, Stephen V.

    Pseudo-scalar meson production in semi-inclusive deep inelastic scattering (SIDIS) at HERMES has provided essential information towards the understanding of the transverse momentum dependent structure of the proton. SIDIS dihadron (hadron pair) production also provides access to the structure of the proton and is complimentary to that provided by pseudo-scalars production, as the same parton distribution functions are involved. For example, while pion and kaon final states allow access to flavor combinations of the Sivers distribution function, SIDIS meson production (included in the K +K- dihadron sample) allows direct access to the Sivers function for the strange quarks. The Sivers function for strange quarks is also related to the orbital angular momentum of the gluons. In the SIDIS cross section, the distribution functions are integrated with fragmentation functions for the respective final states. These fragmentation functions yield information regarding the quark hadronization process. Of particular interest, the Lund/Artru model of fragmentation makes specific predictions regarding the relation between results for dihadron and pseudo-scalar meson production for certain transverse momentum dependent moments. This dissertation presents the first transverse momentum dependent (non-collinear) analysis of the transverse target moments in SIDIS dihadron production, extracting results from the 2002--2005 HERMES data set for pi +pi0, pi+pi-, pi -pi0 and K+ K- dihadrons. A new transverse momentum dependent Monte Carlo generator, TMDGen, is also introduced. Additionally, several theoretical developments have been completed, including a new partial wave analysis of the fragmentation functions, computation of the next-to-leading twist dihadron cross section, and the first model calculation for transverse momentum dependent dihadron fragmentation functions.

  1. Elastic and inelastic scattering of polarized protons from carbon-12 at 400, 600, and 700 MeV

    SciTech Connect

    Jones, K.W.

    1984-04-01

    Good resolution cross section and analyzing power (p vector, p') data for many states in /sup 12/C up to an excitation energy of 21 MeV and spanning a momentum transfer range of 0.3 to 2.1 fm/sup -1/ were obtained using the High Resolution Spectrometer at the Clinton P. Anderson Meson Physics Facility at incident beam energies of 398, 597, and 698 MeV. Optical model potentials were obtained from the elastic scattering data. Inelastic data were analyzed in the Distorted Wave Impulse Approximation using the Love-Franey effective nucleon-nucleon interaction. The energy dependent isoscalar natural parity cross sections were underestimated, while phase difficulties were encountered in fitting analyzing powers. The energy independent isovector natural parity cross sections were reasonably reproduced, but analyzing powers were not, the calculations yielding positive trends whereas the data are of opposite sign. The energy independent isoscalar and isovector unnatural parity cross sections were quite well reproduced up to moderate momentum transfers, and striking successes were observed for some analyzing power data. Systematics of energy dependence together with the results of the DWIA calculations permitted the assignment of spin, parity and isospin quantum numbers to states in the 18-21 MeV excitation region. 64 references.

  2. Structure of the low-lying 2/sup +/ states in /sup 14/C from inelastic pion scattering

    SciTech Connect

    Hayes, A.C.; Chakravarti, S.; Dehnhard, D.; Ellis, P.J.; Holtkamp, D.B.; Lung, L.; Seestrom-Morris, S.J.; Baer, H.; Morris, C.L.; Greene, S.J.; and others

    1988-04-01

    Differential cross sections for inelastic pion scattering from /sup 14/C measured at T/sub ..pi../ = 164 MeV, for the 2/sub 1//sup +/ and 2/sub 2//sup +/ states and an unresolved peak at 10.4 MeV, were analyzed by distorted-wave impulse approximation and coupled-channel calculations using transition densities derived from large scale shell model calculations. The pion and B(E2) data showed strong quenching of the isovector component for the 2/sub 1//sup +/ transition, which required different effective charges for the p and sd shells. The pion data for the 2/sub 2//sup +/ are an order of magnitude smaller than for the 2/sub 1//sup +/ state, and this was understood in terms of strong cancellations between the neutron and proton transition amplitudes. This transition was found to be very sensitive to details of the calculations. The 10.4 MeV data were consistent with the excitation of a 3/sup -/ state.

  3. Peripheral elastic and inelastic scattering of {sup 17,18}O on light targets at 12 MeV/nucleon

    SciTech Connect

    Carstoiu, F.; Al-Abdullah, T.; Gagliardi, C. A.; Trache, L.

    2015-02-24

    The elastic and inelastic scattering of {sup 17,18}O with light targets has been undertaken at 12 MeV/nucleon in order to determine the optical potentials needed for the transfer reaction {sup 13}C({sup 17}O,{sup 18}O){sup 12}C. Optical potentials in both incoming and outgoing channels have been determined in a single experiment. This transfer reaction was used to infer the direct capture rate to the {sup 17}F(p,γ){sup 18}Ne which is essential to estimate the production of {sup 18}F at stellar energies in ONe novae. We demonstrate the stability of the ANC method and OMP results using good quality elastic and inelastic scattering data with stable beams. The peripherality of our reaction is inferred from a semiclassical decomposition of the total scattering amplitude into barrier and internal barrier components. Comparison between elastic scattering of {sup 17}O, {sup 18}O and {sup 16}O projectiles is made.

  4. Transverse dynamics of water across the melting point: A parallel neutron and x-ray inelastic scattering study

    SciTech Connect

    Cunsolo A.; Kodituwakku C.; Bencivenga, F.; Frontzek, M.; Leu, b.M.; Said, A.H.

    2012-05-29

    Joint inelastic neutron and x-ray scattering measurements have been performed on heavy water across the melting point. The spectra bear clear evidence of low- and high-frequency inelastic shoulders related to transverse and longitudinal modes, respectively. Upon increasing the momentum transfer, the spectral shape evolves from a viscoelastic regime, where the low-frequency mode is clearly over-damped, toward an elastic one where its propagation becomes instead allowed. The crossover between the two regimes occurs whenever both the characteristic frequency and the linewidth of the low-frequency mode match the inverse of the structural relaxation time. Furthermore, we observe that the frequency of the transverse mode undergoes a discontinuity across the melting, whose extent reduces upon increasing the exchanged momentum.

  5. Theory of inelastic multiphonon scattering and carrier capture by defects in semiconductors: Application to capture cross sections

    NASA Astrophysics Data System (ADS)

    Barmparis, Georgios D.; Puzyrev, Yevgeniy S.; Zhang, X.-G.; Pantelides, Sokrates T.

    2015-12-01

    Inelastic scattering and carrier capture by defects in semiconductors are the primary causes of hot-electron-mediated degradation of power devices, which holds up their commercial development. At the same time, carrier capture is a major issue in the performance of solar cells and light-emitting diodes. A theory of nonradiative (multiphonon) inelastic scattering by defects, however, is nonexistent, while the theory for carrier capture by defects has had a long and arduous history. Here we report the construction of a comprehensive theory of inelastic scattering by defects, with carrier capture being a special case. We distinguish between capture under thermal equilibrium conditions and capture under nonequilibrium conditions, e.g., in the presence of an electrical current or hot carriers where carriers undergo scattering by defects and are described by a mean free path. In the thermal-equilibrium case, capture is mediated by a nonadiabatic perturbation Hamiltonian, originally identified by Huang and Rhys and by Kubo, which is equal to linear electron-phonon coupling to first order. In the nonequilibrium case, we demonstrate that the primary capture mechanism is within the Born-Oppenheimer approximation (adiabatic transitions), with coupling to the defect potential inducing Franck-Condon electronic transitions, followed by multiphonon dissipation of the transition energy, while the nonadiabatic terms are of secondary importance (they scale with the inverse of the mass of typical atoms in the defect complex). We report first-principles density-functional-theory calculations of the capture cross section for a prototype defect using the projector-augmented wave, which allows us to employ all-electron wave functions. We adopt a Monte Carlo scheme to sample multiphonon configurations and obtain converged results. The theory and the results represent a foundation upon which to build engineering-level models for hot-electron degradation of power devices and the performance

  6. Persistence of Covalent Bonding in Liquid Silicon Probed by Inelastic X-Ray Scattering

    NASA Astrophysics Data System (ADS)

    Okada, J. T.; Sit, P. H.-L.; Watanabe, Y.; Wang, Y. J.; Barbiellini, B.; Ishikawa, T.; Itou, M.; Sakurai, Y.; Bansil, A.; Ishikawa, R.; Hamaishi, M.; Masaki, T.; Paradis, P.-F.; Kimura, K.; Ishikawa, T.; Nanao, S.

    2012-02-01

    Metallic liquid silicon at 1787 K is investigated using x-ray Compton scattering. An excellent agreement is found between the measurements and the corresponding Car-Parrinello molecular dynamics simulations. Our results show persistence of covalent bonding in liquid silicon and provide support for the occurrence of theoretically predicted liquid-liquid phase transition in supercooled liquid states. The population of covalent bond pairs in liquid silicon is estimated to be 17% via a maximally localized Wannier function analysis. Compton scattering is shown to be a sensitive probe of bonding effects in the liquid state.

  7. Validity of generalized scattering equations and corresponding inelastic-cross-section expressions for comprehensive electron diffraction conditions

    NASA Astrophysics Data System (ADS)

    Allen, L. J.; Josefsson, T. W.

    1996-05-01

    Generalized scattering equations for electron diffraction in a crystalline environment have recently been derived with the assumption that the zeroth-order Laue zone (ZOLZ) lies parallel to the crystal surface (or alternatively that the zone axis is parallel to the crystal surface normal) [L. J. Allen and T. W. Josefsson, Phys. Rev. B 52, 3184 (1995)]. The contribution from higher-order Laue zones (HOLZ's) was not considered. We show that these scattering equations are in fact valid for general orientations of the ZOLZ with respect to the crystal surface, except for the specific case where the ZOLZ lies perpendicular to the surface. Furthermore, a widely applicable expression for the cross section for any type of inelastic scattering in a crystal is shown to be valid for any orientation of the ZOLZ and allows the inclusion of reflections in the HOLZ's.

  8. Direct observation of electronic and nuclear ground state splitting in external magnetic field by inelastic neutron scattering on oxidized ferrocene and ferrocene containing polymers

    NASA Astrophysics Data System (ADS)

    Appel, Markus; Frick, Bernhard; Elbert, Johannes; Gallei, Markus; Stühn, Bernd

    2015-01-01

    The quantum mechanical splitting of states by interaction of a magnetic moment with an external magnetic field is well known, e.g., as Zeeman effect in optical transitions, and is also often seen in magnetic neutron scattering. We report excitations observed in inelastic neutron spectroscopy on the redox-responsive polymer poly(vinylferrocene). They are interpreted as splitting of the electronic ground state in the organometallic ferrocene units attached to the polymer chain where a magnetic moment is created by oxidation. In a second experiment using high resolution neutron backscattering spectroscopy we observe the hyperfine splitting, i.e., interaction of nuclear magnetic moments with external magnetic fields leading to sub-μeV excitations observable in incoherent neutron spin-flip scattering on hydrogen and vanadium nuclei.

  9. Single-band model of resonant inelastic x-ray scattering by quasiparticles in high-T(c) cuprate superconductors.

    PubMed

    Benjamin, David; Klich, Israel; Demler, Eugene

    2014-06-20

    We show that a simple model of noninteracting quasiparticles accurately describes resonant inelastic x-ray scattering (RIXS) experiments in the hole-doped cuprate superconductors. Band structure alone yields signatures previously attributed to collective magnetic modes, such as the dispersing peaks and nontrivial polarization dependence found in several experiments. We conclude that RIXS data can be explained without positing the existence of magnetic excitations that persist with increasing doping. In so doing we develop a formalism for RIXS in itinerant electron systems that accounts for the positively charged core hole exactly and discover a mechanism by which the core hole produces polarization dependence mimicking that of a magnetic system. PMID:24996103

  10. Resonant inelastic soft x-ray scattering of CdS: a two-dimensional electronic structure map approach

    SciTech Connect

    Weinhardt, L.; Fuchs, O.; Fleszar, A.; Bar, M.; Blum, M.; Weigand, M.; Denlinger, J.D.; Yang, W.; Hanke, W.; Umbach, E.; Heske, C.

    2008-09-24

    Resonant inelastic x-ray scattering (RIXS) with soft x-rays is uniquely suited to study the elec-tronic structure of a variety of materials, but is currently limited by low (fluorescence yield) count rates. This limitation is overcome with a new high-transmission spectrometer that allows to measure soft x-ray RIXS"maps." The S L2,3 RIXS map of CdS is discussed and compared with density functional calculations. The map allows the extraction of decay channel-specific"absorp-tion spectra," giving detailed insight into the wave functions of occupied and unoccupied elec-tronic states.

  11. A setup for resonant inelastic soft x-ray scattering on liquids at free electron laser light sources

    SciTech Connect

    Kunnus, Kristjan; Schreck, Simon; Foehlisch, Alexander; Eckert, Sebastian; Beye, Martin; Suljoti, Edlira; Weniger, Christian; Wernet, Philippe; Kalus, Christian; Nordlund, Dennis; Zhang, Wenkai; Hartsock, Robert W.; Gaffney, Kelly J.; Schlotter, William F.; Turner, Joshua J.; Kennedy, Brian; and others

    2012-12-15

    We present a flexible and compact experimental setup that combines an in vacuum liquid jet with an x-ray emission spectrometer to enable static and femtosecond time-resolved resonant inelastic soft x-ray scattering (RIXS) measurements from liquids at free electron laser (FEL) light sources. We demonstrate the feasibility of this type of experiments with the measurements performed at the Linac Coherent Light Source FEL facility. At the FEL we observed changes in the RIXS spectra at high peak fluences which currently sets a limit to maximum attainable count rate at FELs. The setup presented here opens up new possibilities to study the structure and dynamics in liquids.

  12. The single particle dynamics of iodine in the Sachs-Teller regime: An inelastic x-ray scattering study

    SciTech Connect

    Izzo, M. G.; Bencivenga, F.; Di Fonzo, S.; Cunsolo, A.; Verbeni, R.; De Lorenzo, R. Gimenez

    2010-09-28

    The high frequency dynamics of liquid iodine has been investigated by deep inelastic x-ray scattering at exchanged wave-vectors (q) ranging from 2.5 to 15 A{sup -1}. The experimental data have been analyzed in the frame of the Sachs-Teller theory of the molecular spectrum while accounting for final state corrections to the lineshape. The performed data analysis carries insights on physical quantities as relevant as the mean rototranslational kinetic energy and the mean square Laplacian of the intermolecular potential. In both cases the measured values are consistent with corresponding theoretical expectations.

  13. Influence of magnetism on phonons in CaFe2As2 as seen via inelastic x-ray scattering

    SciTech Connect

    Hahn, S.E.; Lee, Y.; Ni, N.; Canfield, P.C.; Goldman, A.I.; McQueeney, R.J.; Harmon, B.N.; Alatas, A.; Leu, B.M.; Alp, E.E.; Chung, D.Y.; Todorov, I.S.; Kanatzidis, M.G.

    2009-06-19

    In the iron pnictides, the strong sensitivity of the iron magnetic moment to the arsenic position suggests a significant relationship between phonons and magnetism. We measured the phonon dispersion of several branches in the high-temperature tetragonal phase of CaFe{sub 2}As{sub 2} using inelastic x-ray scattering on single-crystal samples. These measurements were compared to ab initio calculations of the phonons. Spin-polarized calculations imposing the antiferromagnetic order present in the low-temperature orthorhombic phase dramatically improve agreement between theory and experiment. This is discussed in terms of the strong antiferromagnetic correlations that are known to persist in the tetragonal phase.

  14. Resonant inelastic X-ray scattering spectrometer with 25 meV resolution at the Cu K-edge.

    PubMed

    Ketenoglu, Didem; Harder, Manuel; Klementiev, Konstantin; Upton, Mary; Taherkhani, Mehran; Spiwek, Manfred; Dill, Frank Uwe; Wille, Hans Christian; Yavaş, Hasan

    2015-07-01

    An unparalleled resolution is reported with an inelastic X-ray scattering instrument at the Cu K-edge. Based on a segmented concave analyzer, featuring single-crystal quartz (SiO₂) pixels, the spectrometer delivers a resolution near 25 meV (FWHM) at 8981 eV. Besides the quartz analyzer, the performance of the spectrometer relies on a four-bounce Si(553) high-resolution monochromator and focusing Kirkpatrick-Baez optics. The measured resolution agrees with the ray-tracing simulation of an ideal spectrometer. The performance of the spectrometer is demonstrated by reproducing the phonon dispersion curve of a beryllium single-crystal.

  15. Resonant inelastic X-ray scattering spectrometer with 25meV resolution at the Cu K -edge

    DOE PAGESBeta

    Ketenoglu, Didem; Harder, Manuel; Klementiev, Konstantin; Upton, Mary; Taherkhani, Mehran; Spiwek, Manfred; Dill, Frank-Uwe; Wille, Hans-Christian; Yavaş, Hasan

    2015-06-27

    An unparalleled resolution is reported with an inelastic X-ray scattering instrument at the CuK-edge. Based on a segmented concave analyzer, featuring single-crystal quartz (SiO2) pixels, the spectrometer delivers a resolution near 25meV (FWHM) at 8981eV. Besides the quartz analyzer, the performance of the spectrometer relies on a four-bounce Si(553) high-resolution monochromator and focusing Kirkpatrick–Baez optics. The measured resolution agrees with the ray-tracing simulation of an ideal spectrometer. The performance of the spectrometer is demonstrated by reproducing the phonon dispersion curve of a beryllium single-crystal.

  16. Next-to-leading order weighted Sivers asymmetry in semi-inclusive deep inelastic scattering: three-gluon correlator

    SciTech Connect

    Dai, Lingyun; Prokudin, Alexei; Kang, Zhong-Bo; Vitev, Ivan

    2015-09-01

    We study the three-gluon correlation function contribution to the Sivers asymmetry in semi-inclusive deep inelastic scattering. We first establish the matching between the usual twist-3 collinear factorization approach and transverse momentum dependent factorization formalism for the moderate transverse momentum region. We then derive the so-called coefficient functions used in the usual TMD evolution formalism. Finally, we perform the next-to-leading order calculation for the transverse-momentum-weighted spin-dependent differential cross section, from which we identify the QCD collinear evolution of the twist-3 Qiu-Sterman function: the off-diagonal contribution from the three-gluon correlation functions.

  17. Encapsulation of paclitaxel into a bio-nanocomposite. A study combining inelastic neutron scattering to thermal analysis and infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Martins, Murillo L.; Orecchini, Andrea; Aguilera, Luis; Eckert, Juergen; Embs, Jan; Matic, Aleksander; Saeki, Margarida J.; Bordallo, Heloisa N.

    2015-01-01

    The anticancer drug paclitaxel was encapsulated into a bio-nanocomposite formed by magnetic nanoparticles, chitosan and apatite. The aim of this drug carrier is to provide a new perspective against breast cancer. The dynamics of the pure and encapsulated drug were investigated in order to verify possible molecular changes caused by the encapsulation, as well as to follow which interactions may occur between paclitaxel and the composite. Fourier transformed infrared spectroscopy, thermal analysis, inelastic and quasi-elastic neutron scattering experiments were performed. These very preliminary results suggest the successful encapsulation of the drug.

  18. Direct inelastic scattering of N/sub 2/ from Ag(111). I. Rotational populations and alignment

    SciTech Connect

    Sitz, G.O.; Kummel, A.C.; Zare, R.N.

    1988-08-15

    The rotational state populations and the quadrupole and hexadecapole alignment moments of N/sub 2/ scattered off clean Ag(111) are determined by resonance enhanced multiphoton ionization (REMPI). The scattered N/sub 2/ is found to be highly aligned with its rotational angular momentum vector J parallel to the surface. The degree of alignment is found to increase with increasing rotational excitation. We see less than perfect alignment at intermediate J values indicating that the surface is not completely flat. The alignment is relatively insensitive to incident energy, incident angle, or surface temperature T/sub s/. However, the rotational state population distributions show pronounced rainbows for higher incident energy and/or more grazing exit angle. The rotational state distributions are found to depend strongly on the final scattering angle at low T/sub s/; this effect is markedly reduced at higher T/sub s/. Time-of-flight measurements are used to determine the average velocity of the scattered N/sub 2/ as a function of rotational level. It is found that higher rotational excitation correlates with lower average velocity and that the incident molecules lose 20%--30% of their translational energy to the solid. No correlation is found between velocity and alignment. A comparison is made with published results for the NO/Ag(111) system and a variety of theoretical models found in the literature.

  19. Competition of Brazil nut effect, buoyancy, and inelasticity induced segregation in a granular mixture

    NASA Astrophysics Data System (ADS)

    Brito, R.; Soto, R.

    2009-12-01

    It has been recently reported that a granular mixture in which grains differ in their restitution coefficients presents segregation: the more inelastic particles sink to the bottom. When other segregation mechanisms as buoyancy and the Brazil nut effect are present, the inelasticity induced segregation can compete with them. First, a detailed analysis, based on numerical simulations of two dimensional systems, of the competition between buoyancy and the inelasticity induced segregation is presented, finding that there is a transition line in the parameter space that determines which mechanism is dominant. In the case of neutrally buoyant particles having different sizes the inelasticity induced segregation can compete with the Brazil nut effect (BNE). Reverse Brazil nut effect (RBNE) could be obtained at large inelasticities of the intruder. At intermediate values, BNE and RBNE coexist and large inelastic particles are found both near the bottom and at the top of the system.

  20. Measurement of the Target-Normal Single-Spin Asymmetry in Deep-Inelastic Scattering from the Reaction 3He{uparrow}(e,e')X

    SciTech Connect

    Katich, Joseph; Qian, Xin; Zhao, Yuxiang; Allada, Kalyan; Aniol, Konrad; Annand, John; Averett, Todd; Benmokhtar, Fatiha; Bertozzi, William; Bradshaw, Elliott; Bosted, Peter; Camsonne, Alexandre; Canan, Mustafa; Cates, Gordon; Chen, Chunhua; Chen, Jian-Ping; Chen, Wei; Chirapatpimol, Khem; Chudakov, Eugene; Cisbani, Evaristo; Cornejo, Juan; Cusanno, Francesco; Dalton, Mark; Deconinck, Wouter; De Jager, Cornelis; De Leo, Raffaele; Deng, Xiaoyan; Deur, Alexandre; Ding, Huaibo; Dolph, Peter; Dutta, Chiranjib; Dutta, Dipangkar; El Fassi, Lamiaa; Frullani, Salvatore; Gao, Haiyan; Garibaldi, Franco; Gaskell, David; Gilad, Gilad; Gilman, Ronald; Glamazdin, Oleksandr; Golge, Serkan; Guo, Lei; Hamilton, David; Hansen, Jens-Ole; Higinbotham, Douglas; Holmstrom, Timothy; Huang, Jijun; Huang, Min; Ibrahim Abdalla, Hassan; Iodice, Mauro; Jin, Ge; Jones, Mark; Kelleher, Aidan; Kim, Wooyoung; Kolarkar, Ameya; Korsch, Wolfgang; LeRose, John; Li, Xiaomei; Li, Y; Lindgren, Richard; Liyanage, Nilanga; Long, Elena; Lu, Hai-jiang; Margaziotis, Demetrius; Markowitz, Pete; Marrone, Stefano; McNulty, Dustin; Meziani, Zein-Eddine; Michaels, Robert; Moffit, Bryan; Munoz Camacho, Carlos; Nanda, Sirish; Narayan, Amrendra; Nelyubin, Vladimir; Norum, Blaine; Oh, Yoomin; Osipenko, Mikhail; Parno, Diana; Peng, Jen-chieh; Phillips, Sarah; Posik, Matthew; Puckett, Andrew; Qiang, Yi; Rakhman, Abdurahim; Ransome, Ronald; Riordan, Seamus; Saha, Arunava; Sawatzky, Bradley; Schulte, Elaine; Shahinyan, Albert; Hashemi Shabestari, Mitra; Sirca, Simon; Stepanyan, Stepan; Subedi, Ramesh; Sulkosky, Vincent; Tang, Liguang; Tobias, William; Urciuoli, Guido; Vilardi, Ignazio; Wang, Kebin; Wang, Y; Wojtsekhowski, Bogdan; Yan, X; Yao, Huan; Ye, Yunxiu; Ye, Z; Yuan, Lulin; Zhan, Xiaohui; Zhang, Yi; Zhang, Y -W; Zhao, Bo; Zheng, Xiaochao; Zhu, Lingyan; Zhu, Xiaofeng; Zong, Xing

    2014-07-01

    We report the first measurement of the target single-spin asymmetry in deep-inelastic scattering from the inclusive reaction 3He{uparrow}(e,e')X on a 3He gas target polarized normal to the lepton plane. Assuming time-reversal invariance, this asymmetry is strictly zero in the Born approximation. The experiment, conducted at Jefferson Lab using a 5.89 GeV electron beam, covers a range of 1.7effective nucleon polarization and measured proton-to-3He cross section ratios. The measured neutron asymmetries are negative with an average value of (−1.04+/-0.38)×10−2 for invariant mass W>2 GeV, which is non-zero at the 2.75sigma level. Theoretical calculations, which assume two-photon exchange with quasi-free quarks, predict a neutron asymmetry of O(10−4) when both photons couple to one quark, and O(10−2) for the photons coupling to different quarks. Our measured asymmetry agrees both in sign and magnitude with the prediction that uses input based on the Sivers transverse momentum distribution obtained from semi-inclusive deep-inelastic scattering.

  1. Inelastic cross sections for low-energy electrons in liquid water: exchange and correlation effects.

    PubMed

    Emfietzoglou, Dimitris; Kyriakou, Ioanna; Garcia-Molina, Rafael; Abril, Isabel; Nikjoo, Hooshang

    2013-11-01

    Low-energy electrons play a prominent role in radiation therapy and biology as they are the largest contributor to the absorbed dose. However, no tractable theory exists to describe the interaction of low-energy electrons with condensed media. This article presents a new approach to include exchange and correlation (XC) effects in inelastic electron scattering at low energies (below ∼10 keV) in the context of the dielectric theory. Specifically, an optical-data model of the dielectric response function of liquid water is developed that goes beyond the random phase approximation (RPA) by accounting for XC effects using the concept of the many-body local-field correction (LFC). It is shown that the experimental energy-loss-function of liquid water can be reproduced by including into the RPA dispersion relations XC effects (up to second order) calculated in the time-dependent local-density approximation with the addition of phonon-induced broadening in N. D. Mermin's relaxation-time approximation. Additional XC effects related to the incident and/or struck electrons are included by means of the vertex correction calculated by a modified Hubbard formula for the exchange-only LFC. Within the first Born approximation, the present XC corrections cause a significantly larger reduction (∼10-50%) to the inelastic cross section compared to the commonly used Mott and Ochkur approximations, while also yielding much better agreement with the recent experimental data for amorphous ice. The current work offers a manageable, yet rigorous, approach for including non-Born effects in the calculation of inelastic cross sections for low-energy electrons in liquid water, which due to its generality, can be easily extended to other condensed media.

  2. Advanced in-situ measurement of soil carbon content using inelastic neutron scattering

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Measurement and mapping of natural and anthropogenic variations in soil carbon stores is a critical component of any soil resource evaluation process. Emerging modalities for soil carbon analysis in the field is the registration of gamma rays from soil under neutron irradiation. The inelastic neutro...

  3. Resonances in rotationally inelastic scattering of NH{sub 3} and ND{sub 3} with H{sub 2}

    SciTech Connect

    Ma, Qianli; Dagdigian, Paul J.; Avoird, Ad van der Meerakker, Sebastiaan Y. T. van de; Loreau, Jérôme

    2015-07-28

    We present theoretical studies on the scattering resonances in rotationally inelastic collisions of NH{sub 3} and ND{sub 3} molecules with H{sub 2} molecules. We use the quantum close-coupling method to compute state-to-state integral and differential cross sections for the NH{sub 3}/ND{sub 3}–H{sub 2} system for collision energies between 5 and 70 cm{sup −1}, using a previously reported potential energy surface [Maret et al., Mon. Not. R. Astron. Soc. 399, 425 (2009)]. We identify the resonances as shape or Feshbach resonances. To analyze these, we use an adiabatic bender model, as well as examination at the scattering wave functions and lifetimes. The strength and width of the resonance peaks suggest that they could be observed in a crossed molecular beam experiment involving a Stark-decelerated NH{sub 3} beam.

  4. Application of the semiclassical perturbation (SCP) approximation to diffraction and rotationally inelastic scattering of atoms and molecules from surfaces

    SciTech Connect

    Hubbard, L.M.; Miller, W.H.

    1983-02-15

    The semiclassical perturbation (SCP) approximation of Miller and Smith (Phys. Rev. A 17, 17 (1978)) is applied to the scattering of atoms and molecules from crystal surfaces. Specifically, diffraction of He from LiF, and diffraction and rotationally inelastic scattering of H/sub 2/ from LiF are treated, and the SCP model is seen to agree well with earlier coupled-channel and quantum sudden calculations. These tests of the SCP model are all for ''soft'' interaction potentials, e.g., of the Lennard-Jones Devonshire variety, but it is also shown that the model behaves correctly in the limit of an impulsive hard-wall potential function. The SCP picture thus appears to have a wide range of validity for describing the dynamics of gas-surface collisions.

  5. Isospin Character of Low-Lying Pygmy Dipole States in Pb208 via Inelastic Scattering of O17 Ions

    NASA Astrophysics Data System (ADS)

    Crespi, F. C. L.; Bracco, A.; Nicolini, R.; Mengoni, D.; Pellegri, L.; Lanza, E. G.; Leoni, S.; Maj, A.; Kmiecik, M.; Avigo, R.; Benzoni, G.; Blasi, N.; Boiano, C.; Bottoni, S.; Brambilla, S.; Camera, F.; Ceruti, S.; Giaz, A.; Million, B.; Morales, A. I.; Vandone, V.; Wieland, O.; Bednarczyk, P.; Ciemała, M.; Grebosz, J.; Krzysiek, M.; Mazurek, K.; Zieblinski, M.; Bazzacco, D.; Bellato, M.; Birkenbach, B.; Bortolato, D.; Calore, E.; Cederwall, B.; Charles, L.; de Angelis, G.; Désesquelles, P.; Eberth, J.; Farnea, E.; Gadea, A.; Görgen, A.; Gottardo, A.; Isocrate, R.; Jolie, J.; Jungclaus, A.; Karkour, N.; Korten, W.; Menegazzo, R.; Michelagnoli, C.; Molini, P.; Napoli, D. R.; Pullia, A.; Recchia, F.; Reiter, P.; Rosso, D.; Sahin, E.; Salsac, M. D.; Siebeck, B.; Siem, S.; Simpson, J.; Söderström, P.-A.; Stezowski, O.; Theisen, Ch.; Ur, C.; Valiente-Dobón, J. J.

    2014-07-01

    The properties of pygmy dipole states in Pb208 were investigated using the Pb208(O17, O17'γ) reaction at 340 MeV and measuring the γ decay with high resolution with the AGATA demonstrator array. Cross sections and angular distributions of the emitted γ rays and of the scattered particles were measured. The results are compared with (γ, γ') and (p, p') data. The data analysis with the distorted wave Born approximation approach gives a good description of the elastic scattering and of the inelastic excitation of the 2+ and 3- states. For the dipole transitions a form factor obtained by folding a microscopically calculated transition density was used for the first time. This has allowed us to extract the isoscalar component of the 1- excited states from 4 to 8 MeV.

  6. Measurement of 56Fe activity produced in inelastic scattering of neutrons created by cosmic muons in an iron shield.

    PubMed

    Krmar, M; Jovančević, N; Nikolić, D

    2012-01-01

    We report on the study of the intensities of several gamma lines emitted after the inelastic scattering of neutrons in (56)Fe. Neutrons were produced via nuclear processes induced by cosmic muons in the 20tons massive iron cube placed at the Earth's surface and used as a passive shield for the HPGe detector. Relative intensities of detected gamma lines are compared with the results collected in the same iron shield by the use of the (252)Cf neutrons. Assessment against the published data from neutron scattering experiments at energies up to 14MeV is also provided. It allowed us to infer the qualitative information about the average energy of muon-created neutrons in the iron shield.

  7. Inelastic neutron scattering study of Ni-substituted Ce0.5Fe4Sb12 skutterudite compounds

    NASA Astrophysics Data System (ADS)

    Girard, L.; Adroja, D. T.; Chapon, L.; Taylor, J. W.; Viennois, R.; Ravot, D.; Paschen, S.

    2012-12-01

    An inelastic neutron scattering study of the filled and partially-filled skutterudite compounds RFe4Sb12 and R0.5Fe2.75Ni1.25Sb12 (where R = Ce and La) was carried out to understand the nature of the spin dynamics. Strong magnetic scattering was observed in Ce0.5Fe2.75Ni1.25Sb12 at ~ 5 meV. The integrated intensity of this peak does not follow the Ce3+ form factor, but exhibits a maximum at a momentum transfer (|Q|) of 2 Å-1. We attribute this feature to a Ce3+ crystal field excitation in the presence of magnetic exchange interactions. This picture is supported by thermodynamic and magnetic properties. Finally, we confirm the presence of a spin gap in CeFe4Sb12 suggested by our previous work.

  8. Inelastic collisional effect on a dilute granular shock layer with a heated wall.

    PubMed

    Yano, R; Suzuki, K

    2011-03-01

    The inelastic collisional effect on a shock layer of a dilute granular gas with a heated wall is numerically studied. To investigate the inelastic collisional effect via the gain term in the inelastic Boltzmann equation on the shock layer, an inelastic Bhatnagar-Gross-Krook (BGK) type equation, whose loss term is equivalent to that in the inelastic Boltzmann equation, is formulated on the basis of the kinetic theory of the granular gas. The inelastic BGK-type equation formulated for a hard-sphere particle is generalized to that for an inverse power law (IPL) molecule. Numerical results in a weakly inelastic regime confirm the nonequilirium contribution to the cooling rate, when the collision frequency depends on the particle velocity. The profile of the negative high-velocity tail of the distribution function in the generation regime of the shock wave obtained by the Direct Simulation Monte Carlo method is higher than that obtained by the proposed BGK-type equation when the collision frequency depends on the particle velocity because of the inelastic collisional effect via the gain term in the inelastic Boltzmann equation, which is not included in the proposed BGK-type equation. PMID:21437794

  9. Role of Inelastic Electron–Phonon Scattering in Electron Transport through Ultra-Scaled Amorphous Phase Change Material Nanostructures

    SciTech Connect

    Liu, Jie; Xu, Xu; Anantram, M.P.

    2014-09-01

    The electron transport through ultra-scaled amorphous phase change material (PCM) GeTe is investigated by using ab initio molecular dynamics, density functional theory, and non-equilibrium Green’s function, and the inelastic electron–phonon scattering is accounted for by using the Born approximation. It is shown that, in ultra-scaled PCM device with 6 nm channel length, < 4 % of the energy carried by the incident electrons from the source is transferred to the atomic lattice before reaching the drain, indicating that the electron transport is largely elastic. Our simulation results show that the inelastic electron–phonon scattering, which plays an important role to excite trapped electrons in bulk PCM devices, exerts very limited influence on the current density value and the shape of current–voltage curve of ultra-scaled PCM devices. The analysis reveals that the Poole–Frenkel law and the Ohm’s law, which are the governing physical mechanisms of the bulk PCM devices, cease to be valid in the ultra-scaled PCM devices.

  10. Antiproton-nucleus inelastic scattering and the spin-isospin dependence of the N anti N interaction

    SciTech Connect

    Dover, C.B.

    1985-01-01

    A general overview of the utility of antinucleon (anti N)-nucleus inelastic scattering studies is presented, emphasizing both the sensitivity of the cross sections to various components of the N anti N transition amplitudes and the prospects for the exploration of some novel aspects of nuclear structure. We start with an examination of the relation between NN and N anti N potentials, focusing on the coherences predicted for the central, spin-orbit and tensor components, and how these may be revealed by measurements of two-body spin observables. We next discuss the role of the nucleus as a spin and isospin filter, and show how, by a judicious choice of final state quantum numbers (natural or unnatural parity states, isospin transfer ..delta..T=0 or 1) and momentum transfer q, one can isolate different components of the N anti N transition amplitude. Various models for the N anti N interaction which give reasonable fits to the available two-body data are shown to lead to strikingly different predictions for certain spin-flip nuclear transitions. We suggest several possible directions for future anti N-nucleus inelastic scattering experiments at LEAR, for instance the study of spin observables which would be accessible with polarized anti N beams, charge exchange reactions, and higher resolution studies of the (anti p, anti p') reaction. We compare the antinucleon and the nucleon as a probe of nuclear modes of excitation. 34 refs.

  11. Electric dipole response of nuclei studied by proton inelastic scattering: neutron thickness, symmetry energy, and pygmy dipole resonance

    NASA Astrophysics Data System (ADS)

    Tamii, Atsushi; RCNP E282/E316/E326/E350/E376/E377 Collaboration

    2014-09-01

    Electric dipole (E1) responses of heavy nuclei have been studied by high-resolution measurement of proton inelastic scattering at forward angles including zero degrees. Here the proton scattering at 300 MeV is used as an electromagnetic probe to extract precisely the distribution of E1 reduced transition probability B(E1). The measurement has been done on various stable nuclei such as 208Pb, 120Sn, 90Zr, 154Sm, and 96Mo. The dipole polarizability and pygmy dipole resonance (PDR) strength has been extracted. Those quantities are considered to have strong correlations to the neutron skin thickness and the first order density dependence of the symmetry energy of the nuclear equation of state. We will present the experimental methods and highlights of the results as well as the preliminary ones of recent analyses. Electric dipole (E1) responses of heavy nuclei have been studied by high-resolution measurement of proton inelastic scattering at forward angles including zero degrees. Here the proton scattering at 300 MeV is used as an electromagnetic probe to extract precisely the distribution of E1 reduced transition probability B(E1). The measurement has been done on various stable nuclei such as 208Pb, 120Sn, 90Zr, 154Sm, and 96Mo. The dipole polarizability and pygmy dipole resonance (PDR) strength has been extracted. Those quantities are considered to have strong correlations to the neutron skin thickness and the first order density dependence of the symmetry energy of the nuclear equation of state. We will present the experimental methods and highlights of the results as well as the preliminary ones of recent analyses. JSPS No. 25105509.

  12. Magnetic Transitions in Iron Porphyrin Halides by Inelastic Neutron Scattering and Ab-initio Studies of Zero-Field Splittings

    SciTech Connect

    Stavretis, Shelby E.; Atanasov, Mihail; Podlesnyak, Andrey A.; Hunter, Seth C.; Neese, Frank; Xue, Zi-Ling

    2015-10-02

    Zero-field splitting (ZFS) parameters of nondeuterated metalloporphyrins [Fe(TPP)X] (X = F, Br, I; H2TPP = tetraphenylporphyrin) are determined by inelastic neutron scattering (INS). The ZFS values are D = 4.49(9) cm–1 for tetragonal polycrystalline [Fe(TPP)F], and D = 8.8(2) cm–1, E = 0.1(2) cm–1 and D = 13.4(6) cm–1, E = 0.3(6) cm–1 for monoclinic polycrystalline [Fe(TPP)Br] and [Fe(TPP)I], respectively. Along with our recent report of the ZFS value of D = 6.33(8) cm–1 for tetragonal polycrystalline [Fe(TPP)Cl], these data provide a rare, complete determination of ZFS parameters in a metalloporphyrin halide series. The electronic structure of [Fe(TPP)X] (X = F, Cl, Br, I) has been studied by multireference ab initio methods: the complete active space self-consistent field (CASSCF) and the N-electron valence perturbation theory (NEVPT2) with the aim of exploring the origin of the large and positive zero-field splitting D of the 6A1 ground state. D was calculated from wave functions of the electronic multiplets spanned by the d5 configuration of Fe(III) along with spin–orbit coupling accounted for by quasi degenerate perturbation theory. Results reproduce trends of D from inelastic neutron scattering data increasing in the order from F, Cl, Br, to I. A mapping of energy eigenvalues and eigenfunctions of the S = 3/2 excited states on ligand field theory was used to characterize the σ- and π-antibonding effects decreasing from F to I. This is in agreement with similar results deduced from ab initio calculations on CrX63- complexes and also with the spectrochemical series showing a decrease of the ligand field in the same directions. A correlation is found between the increase of D and decrease of the π- and σ-antibonding energies eλX (λ = σ, π) in the series from X = F to I. Analysis of this

  13. Hadron mass corrections in semi-inclusive deep-inelastic scattering

    SciTech Connect

    Guerrero Teran, Juan Vicente; Ethier, James J.; Accardi, Alberto; Casper, Steven W.; Melnitchouk, Wally

    2015-09-24

    We found that the spin-dependent cross sections for semi-inclusive lepton-nucleon scattering are derived in the framework of collinear factorization, including the effects of masses of the target and produced hadron at finite Q2. At leading order the cross sections factorize into products of parton distribution and fragmentation functions evaluated in terms of new, mass-dependent scaling variables. Furthermore, the size of the hadron mass corrections is estimated at kinematics relevant for current and future experiments, and the implications for the extraction of parton distributions from semi-inclusive measurements are discussed.

  14. Hadron mass corrections in semi-inclusive deep-inelastic scattering

    DOE PAGESBeta

    Guerrero Teran, Juan Vicente; Ethier, James J.; Accardi, Alberto; Casper, Steven W.; Melnitchouk, Wally

    2015-09-24

    We found that the spin-dependent cross sections for semi-inclusive lepton-nucleon scattering are derived in the framework of collinear factorization, including the effects of masses of the target and produced hadron at finite Q2. At leading order the cross sections factorize into products of parton distribution and fragmentation functions evaluated in terms of new, mass-dependent scaling variables. Furthermore, the size of the hadron mass corrections is estimated at kinematics relevant for current and future experiments, and the implications for the extraction of parton distributions from semi-inclusive measurements are discussed.

  15. Energy dissipation in heavy systems: the transition from quasi-elastic to deep-inelastic scattering

    SciTech Connect

    Rehm, K.E.; van den Berg, A.; Kolata, J.J.; Kovar, D.G.; Kutschera, W.; Rosner, G.; Stephans, G.S.F.; Yntema, J.L.; Lee, L.L.

    1984-01-01

    The interaction of medium mass projectiles (A = 28 - 64) with /sup 208/Pb has been studied using a split-pole spectrograph which allows single mass and charge identification. The reaction process in all systems studied so far is dominated by quasi-elastic neutron transfer reactions, especially at incident energies in the vicinity of the Coulomb barrier. In addition to the quasi-elastic component deep inelastic contributions are present in all reaction channels. The good mass and charge separation allows to generate Wilczynski plots for individual channels; for the system /sup 48/Ti + /sup 208/Pb we observe that the transition between the quasi-elastic and deep-inelastic reactions occurs around Q = -(30 to 35) MeV.

  16. Deuteron spin structure functions in the resonance and deep inelastic scattering regions

    SciTech Connect

    S.A. Kulagin; W. Melnitchouk

    2008-01-01

    We derive relations between spin-dependent nuclear and nucleon g1 and g2 structure functions within the nuclear impulse approximation, which are valid at all Q^2, and in both the resonance and deep inelastic regions. We apply the formalism to the specific case of the deuteron, which is often used as a source of neutron structure information, and compare the size of the nuclear corrections calculated using exact kinematics and using approximations applicable at large Q^2.

  17. Theoretical Calculations of Elastic and Inelastic Scattering of Electrons from Ar^+

    NASA Astrophysics Data System (ADS)

    Griffin, D. C.; Pindzola, M. S.; Shaw, J. A.; Badnell, N. R.

    1996-05-01

    We report on theoretical calculations of differential and partial cross sections for elastic scattering of electrons from Ar^+ and total cross sections for electron-impact excitation and ionization of Ar^+. The elastic scattering calculations are performed using the R-matrix method and are compared to measurements. The excitation cross sections are calculated using both the distorted-wave and the R-matrix close-coupling approximations, while the ionization cross sections are determined from the distorted-wave approximation, and include the effects of final-state correlation. The effects of core polarization and resonance contributions on the excitation cross sections are examined carefully. Rate coefficients for ionization and excitation to the levels of 3p^44p ^4D, together with radiative rates from the levels of 3p^44p ^4D to all possible lower levels, will be entered into the ADAS collisional-radiative modeling codes(H. P. Summers \\underlineADAS User's Manual), JET-IR(94)06. Work supported by the Department of Energy to generate density-dependent parameters for use in the interpretation of on-going emissivity measurements from tokamak plasmas.

  18. Inelastic x-ray scattering study of supercooled liquid and solid silicon.

    SciTech Connect

    Alatas, A.; Said, A.; Sinn, H.; Alp, E.E.; Kodituwakku, C.N.; Saboungi, M.L.; Price, D.L.; X-Ray Science Division; Western Michigan Univ.; Purdue Univ.; CRMD-CNRS; CRMHT-CNRS

    2006-01-01

    Momentum-resolved inelastic x-ray scattering (IXS) technique is one of the powerful methods for the study of dynamical properties of a given system even in extreme conditions like high temperature and high pressure. At the same time, experimental studies of physical and structural properties of liquids have multiplied in recent years with the advent of containerless techniques. These methods reduce the possibility of contamination of specimens and remove external nucleation sites. Therefore, by combining the IXS method with the levitation method, the dynamical properties of stable liquids up to 3000 K and supercooled phase of liquids can be studied. Silicon is a basic material in the semiconductor industry and has been the subject of a large amount of experimental and theoretical studies over a long time. In the crystalline phase at ambient conditions, silicon is a diamond-structured semiconductor, but upon melting it undergoes a semiconductor-to-metal transition accompanied by significant changes in the structure and density. The coordination number increases from 4 in the solid to about 6.5 in the liquid, and liquid density is increased by about 10%. The principal purpose of the present study was to determine silicon's elastic modulus from the measurement of averaged sound speed determined from IXS. The experiments were carried out at the Advanced Photon Source (APS) beamline 3-ID with a high-resolution monochromator consisting of two nested channel-cut crystals and four backscattering analyzer setups in the horizontal scattering plane 6 m from the sample. The requirements for very high energy resolution and the basic principles of such instrumentation are discussed elsewhere as referenced. The levitation apparatus was enclosed in a bell jar specially designed for backscattering geometry with a separation of 10 cm between the sample and the detector. Silicon spheres of 2 to 3 mm in diameter were suspended in an argon gas jet and heated with a 270 W CO{sub 2

  19. Rovibrational Levels and Inelastic Scattering of the H_2O-Ar Cluster in Full and Reduced Dimensionality

    NASA Astrophysics Data System (ADS)

    Ndengue, Steve Alexandre; Majumder, Moumita; Dawes, Richard; Gatti, Fabien; Meyer, Hans-Dieter

    2016-06-01

    The Water-Argon cluster is an important system of fundamental and practical interest. It is for example known to be one of the simplest systems capable of manifesting "hydrophobic interactions" and as such is an ideal candidate for the study of those interactions. On the fundamental level, it is a model system for the description of the intermolecular potential, rovibrational states and inelastic scattering of an atom and an asymmetric top van der Waal complex and thus may serve as a test to perform similar work on other systems. Additionally, the description of the H_2O-Ar intermolecular interaction is an important initial step to a deeper understanding of the static and dynamical properties of condensed phases such H_2O doped in large (Ar)_N clusters. We investigate in this work the H_2O-Ar cluster on a global potential energy surface recently generated. We thus compute the rovibrational energy levels of the cluster in the rigid rotor approximation and in full dimensionality using the MCTDH improved relaxation method and compare our results with available experimental measurements and previous calculations. Then, we present inelastic scattering cross-sections of H_2O+Ar collisions obtained in the rigid rotor approximation using time-independent method and time-dependent method, and compare where available results with previous calculations. Finally, we will discuss the extension of the scattering calculations to the full dimensional case and the prospect of studying rovibrational relaxation within accurate time-dependent quantum calculations on similar systems or clusters.

  20. NMscatt: a program for calculating inelastic scattering from large biomolecular systems using classical force-field simulations

    NASA Astrophysics Data System (ADS)

    Merzel, Franci; Fontaine-Vive, Fabien; Johnson, Mark R.

    2007-09-01

    Computational tools for normal mode analysis, which are widely used in physics and materials science problems, are designed here in a single package called NMscatt (Normal Modes & scattering) that allows arbitrarily large systems to be handled. The package allows inelastic neutron and X-ray scattering observables to be calculated, allowing comparison with experimental data produced at large scale facilities. Various simplification schemes are presented for analyzing displacement vectors, which are otherwise too complicated to understand in very large systems. Program summaryTitle of program:NMscatt Catalogue identifier:ADZA_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADZA_v1_0.html Program obtainable from:CPC Program Library, Queen's University of Belfast, N. Ireland Licensing provisions:no No. of lines in distributed program, including test data, etc.:573 535 No. of bytes in distributed program, including test data, etc.:4 516 496 Distribution format:tar.gz Programming language:FORTRAN 77 Computer:x86 PC Operating system:GNU/Linux, UNIX RAM:Depends on the system size to be simulated Word size:32 or 64 bits Classification:16.3 External routines:LAPACK Nature of problem: Normal mode analysis, phonons calculation, derivation of incoherent and coherent inelastic scattering spectra. Solution method: Full diagonalization (producing eigen-vectors and eigen-values) of dynamical matrix which is obtained from potential energy function derivation using finite difference method. Running time: About 7 hours per one k-point evaluation in sampling all modes dispersion curves for a system containing 3550 atoms in the unit cell on AMD Athlon 64 X2 Dual Core Processor 4200+.

  1. Some inelastic effects of thermal cycling on yttria-stabilized zirconia

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Mcdonald, G.; Bill, R. C.

    1982-01-01

    The effects of inelastic behavior of yttria-stabilized zirconia (YSZ) materials were analyzed. The results show these materials to be sensitive to small changes in temperature and are supported by measurements of inelastic behavior in disc and bar specimens at temperatures as low as 1010 C (1850 F). At higher thermomechanical loadings, the test specimens can deform to strains above 1 percent.

  2. Crystal field excitations in CeCu2Ge2: Revisited employing a single crystal and inelastic neutron scattering

    NASA Astrophysics Data System (ADS)

    Loewenhaupt, Michael; Faulhaber, Enrico; Schneidewind, Astrid; Deppe, Micha; Hradil, Klaudia

    2012-04-01

    The intermetallic compound, CeCu2Ge2, is the counterpart of the heavy-fermion superconductor CeCu2Si2. CeCu2Ge2 is a magnetically ordering (TN = 4.1K) Kondo lattice with a moderate Sommerfeld coefficient of 140 mJ/ molK2. Earlier inelastic neutron measurements on a polycrystalline sample revealed a doublet ground state and a quasi-quartet excited state at 16.5 meV, although a splitting of the 4f1 (J = 5/2) ground state multiplet into 3 doublets is expected from the point symmetry of the Ce3+ ions. We performed detailed inelastic neutron scattering experiments on a single crystal at the thermal triple-axis spectrometer PUMA at FRM II for different crystallographic directions. From our results we infer that the quasi-quartet, in fact, consists of two doublets at 17.0 and 18.3 meV which exhibit a strong directional dependence of their transition matrix elements to the ground state doublet. Finally, we will present a new set of crystal field parameters.

  3. Differential and integral cross sections for the rotationally inelastic scattering of methyl radicals with H{sub 2} and D{sub 2}

    SciTech Connect

    Tkáč, Ondřej; Orr-Ewing, Andrew J.; Ma, Qianli; Dagdigian, Paul J.; Rusher, Cassandra A.; Greaves, Stuart J.

    2014-05-28

    Comparisons are presented of experimental and theoretical studies of the rotationally inelastic scattering of CD{sub 3} radicals with H{sub 2} and D{sub 2} collision partners at respective collision energies of 680 ± 75 and 640 ± 60 cm{sup −1}. Close-coupling quantum-mechanical calculations performed using a newly constructed ab initio potential energy surface (PES) provide initial-to-final CD{sub 3} rotational level (n, k → n′, k′) integral and differential cross sections (ICSs and DCSs). The DCSs are compared with crossed molecular beam and velocity map imaging measurements of angular scattering distributions, which serve as a critical test of the accuracy of the new PES. In general, there is very good agreement between the experimental measurements and the calculations. The DCSs for CD{sub 3} scattering from both H{sub 2} and D{sub 2} peak in the forward hemisphere for n′ = 2–4 and shift more to sideways and backward scattering for n′ = 5. For n′ = 6–8, the DCSs are dominated by backward scattering. DCSs for a particular CD{sub 3} n → n′ transition have a similar angular dependence with either D{sub 2} or H{sub 2} as collision partner. Any differences between DCSs or ICSs can be attributed to mass effects because the PES is unchanged for CD{sub 3}−H{sub 2} and CD{sub 3}–D{sub 2} collisions. Further comparisons are drawn between the CD{sub 3}–D{sub 2} scattering and results for CD{sub 3}–He presented in our recent paper [O. Tkáč, A. G. Sage, S. J. Greaves, A. J. Orr-Ewing, P. J. Dagdigian, Q. Ma, and M. H. Alexander, Chem. Sci. 4, 4199 (2013)]. These systems have the same reduced mass, but are governed by different PESs.

  4. Numerical simulation of scattering of acoustic waves by inelastic bodies using hypersingular boundary integral equation

    SciTech Connect

    Daeva, S.G.; Setukha, A.V.

    2015-03-10

    A numerical method for solving a problem of diffraction of acoustic waves by system of solid and thin objects based on the reduction the problem to a boundary integral equation in which the integral is understood in the sense of finite Hadamard value is proposed. To solve this equation we applied piecewise constant approximations and collocation methods numerical scheme. The difference between the constructed scheme and earlier known is in obtaining approximate analytical expressions to appearing system of linear equations coefficients by separating the main part of the kernel integral operator. The proposed numerical scheme is tested on the solution of the model problem of diffraction of an acoustic wave by inelastic sphere.

  5. Resonant inelastic x-ray scattering study of charge excitations in superconducting and nonsuperconducting PrFeAsO₁₋y

    SciTech Connect

    Jarrige, I.; Nomura, T.; Ishii, K.; Gretarsson, H.; Kim, Y.-J.; Kim, J.; Upton, M.; Casa, D.; Gog, T.; Ishikado, M.; Fukuda, T.; Yoshida, M.; Hill, J. P.; Liu, X.; Hiraoka, N.; Tsuei, K. D.; Shamoto, S.

    2012-09-05

    We report the first observation by momentum-resolved resonant inelastic x-ray scattering of charge excitations in an iron-based superconductor and its parent compound, PrFeAsO₀.₇ and PrFeAsO, respectively, with two main results. First, using calculations based on a 16-band dp model, we show that the energy of the lowest-lying excitations, identified as dd interband transitions of dominant xz,yz orbital character, exhibits a dramatic dependence on electron correlation. This enables us to estimate the Coulomb repulsion U and Hund's coupling J, and to highlight the role played by J in these peculiar orbital-dependent electron correlation effects. Second, we show that short-range antiferromagnetic correlations, which are a prerequisite to the occurrence of these excitations at the Γ point, are still present in the superconducting state.

  6. Expressions for Form Factors for Inelastic Scattering and Charge Exchange in Plane-Wave, Distorted-Wave, and Coupled-Channels Reaction Formalisms

    SciTech Connect

    Dietrich, F S

    2006-09-25

    This document is intended to facilitate calculation of inelastic scattering and charge-exchange cross sections in a variety of reaction models, including the plane-wave and distorted-wave approximations and the full coupled-channels treatments. Expressions are given for the coupling potentials between the relevant channels in both coordinate and momentum space. In particular, it is expected that the plane-wave calculations should be useful as a check on the correctness of coupled-channels calculations. The Fourier transform methods used to calculate the plane-wave approximation cross sections are also intended to be used to generate the transition potentials for coupled-channels codes, using a folding model with local effective interactions. Specific expressions are given for calculating transition densities for the folding model in the random phase approximation (RPA).

  7. On the absence of a positive sound dispersion in the THz dynamics of glycerol: an inelastic x-ray scattering study

    SciTech Connect

    Cunsolo, Alessandro

    2012-10-23

    The high frequency transport properties of glycerol are derived from inelastic x-ray scattering spectra measured at different pressures and compared with ultrasound absorption data. As a result, the presence of two distinct relaxation processes is inferred: a slow one, occurring in the GHz window and having an essentially structural character, and a fast one, related instead to microscopic degrees of freedom. While the former originates a neat increase of the apparent, i.e. frequency-dependent, sound velocity, the latter induces no visible dispersive effects on the acoustic propagation. The observed behavior is likely paradigmatic of all glass formers near or below the melting and it is here discussed and explained in some detail.

  8. Inelastic x-ray scattering studies of phonons propagating along the axial direction of a DNA molecule having different counter-ion atmosphere.

    SciTech Connect

    Liu, Y.; Berti, D.; Baglioni, P.; Chen, S. H.; Alatas, A.; Sinn, H.; Said, A.; Alp, E. E.; Experimental Facilities Division; Massachusetts Inst. of Technology; Univ. of Florence

    2005-01-01

    Shear-aligned 40 wt% calf-thymus Na-DNA molecules in aqueous solutions are prepared in their liquid crystalline phases and studied by high resolution inelastic X-ray scattering (IXS). Measured IXS spectra are analyzed with the generalized three effective eigenmode (GTEE) theory. The phonon dispersion relations along the axial direction of DNA molecules with different MgCl2 concentrations are constructed and compared. It is found that the sound speed along the axial direction of DNA molecules varies only slightly, but the phonon dampening is greatly affected with the increase amount of MgCl{sub 2} concentration. Using the GTEE theory, we are able to extract the longitudinal viscosity in the hydrodynamic limit from the Q-dependence of a fitted parameter. We make a comprehensive review of the GTEE theory and discuss detailed analyses of IXS spectra taking into account finite energy resolution of the instrument.

  9. Determination of the gluon distribution function of the nucleon using energy-energy angular pattern in deep-inelastic muon-deuteron scattering

    NASA Astrophysics Data System (ADS)

    Adams, M. R.; Aïd, S.; Anthony, P. L.; Baker, M. D.; Bartlett, J.; Bhatti, A. A.; Braun, H. M.; Busza, W.; Carroll, T. J.; Conrad, J. M.; Coutrakon, G.; Davisson, R.; Derado, I.; Dhawan, S. K.; Dougherty, W.; Dreyer, T.; Dziunikowska, K.; Eckardt, V.; Ecker, U.; Erdmann, M.; Eskreys, A.; Figiel, J.; Gebauer, H. J.; Geesaman, D. F.; Gilman, R.; Green, M. C.; Haas, J.; Halliwell, C.; Hanlon, J.; Hantke, D.; Hughes, V. W.; Jackson, H. E.; Jancso, G.; Jansen, D. M.; Kaufman, S.; Kennedy, R. D.; Kirk, T.; Kobrak, H. G. E.; Krzywdzinski, S.; Kunori, S.; Lord, J. J.; Lubatti, H. J.; McLeod, D.; Magill, S.; Malecki, P.; Manz, A.; Melanson, H.; Michael, D. G.; Mohr, W.; Montgomery, H. E.; Morfin, J. G.; Nickerson, R. B.; O'Day, S.; Olkiewicz, K.; Osborne, L.; Papavassiliou, V.; Pawlik, B.; Pipkin, F. M.; Ramberg, E. J.; Röser, A.; Ryan, J. J.; Salgado, C. W.; Salvarani, A.; Schellman, H.; Schmitt, M.; Schmitz, N.; Schüler, K. P.; Seyerlein, H. J.; Skuja, A.; Snow, G. A.; Söldner-Rembold, S.; Steinberg, P. H.; Stier, H. E.; Stopa, P.; Swanson, R. A.; Talaga, R.; Tentindo-Repond, S.; Trost, H. J.; Venkataramania, H.; Wilhelm, M.; Wilkes, J.; Wilson, Richard; Wittek, W.; Wolbers, S. A.; Zhao, T.

    1996-03-01

    We have used the energy-energy angular pattern of hadrons in inelastic muon-deuteron scattering to study perturbative QCD effects and to extract the gluon distribution function ηG( η) of the nucleon, where η is the fractional momentum carried by the gluon. The data were taken with the E665 spectrometer using the Fermilab Tevatron muon beam with a mean beam energy of 490 GeV. We present ηG( η) for 0.005< η<0.05 and at an average Q 2 of 8 GeV2 using this new technique. We find that ηG( η) in this region can be described by ηG( η) α ηλ with λ=-0.87±0.09( stat.)±{0.37/0.32}( sys.). We compare our results to expectations from various parametrizations of the parton distribution function and also to results from HERA.

  10. Resonant inelastic x-ray scattering study of charge excitations in superconducting and nonsuperconducting PrFeAsO₁₋y

    DOE PAGESBeta

    Jarrige, I.; Nomura, T.; Ishii, K.; Gretarsson, H.; Kim, Y.-J.; Kim, J.; Upton, M.; Casa, D.; Gog, T.; Ishikado, M.; et al

    2012-09-05

    We report the first observation by momentum-resolved resonant inelastic x-ray scattering of charge excitations in an iron-based superconductor and its parent compound, PrFeAsO₀.₇ and PrFeAsO, respectively, with two main results. First, using calculations based on a 16-band dp model, we show that the energy of the lowest-lying excitations, identified as dd interband transitions of dominant xz,yz orbital character, exhibits a dramatic dependence on electron correlation. This enables us to estimate the Coulomb repulsion U and Hund's coupling J, and to highlight the role played by J in these peculiar orbital-dependent electron correlation effects. Second, we show that short-range antiferromagnetic correlations,more » which are a prerequisite to the occurrence of these excitations at the Γ point, are still present in the superconducting state.« less

  11. Resonant inelastic X-ray scattering spectrometer with 25 meV resolution at the Cu K-edge.

    PubMed

    Ketenoglu, Didem; Harder, Manuel; Klementiev, Konstantin; Upton, Mary; Taherkhani, Mehran; Spiwek, Manfred; Dill, Frank Uwe; Wille, Hans Christian; Yavaş, Hasan

    2015-07-01

    An unparalleled resolution is reported with an inelastic X-ray scattering instrument at the Cu K-edge. Based on a segmented concave analyzer, featuring single-crystal quartz (SiO₂) pixels, the spectrometer delivers a resolution near 25 meV (FWHM) at 8981 eV. Besides the quartz analyzer, the performance of the spectrometer relies on a four-bounce Si(553) high-resolution monochromator and focusing Kirkpatrick-Baez optics. The measured resolution agrees with the ray-tracing simulation of an ideal spectrometer. The performance of the spectrometer is demonstrated by reproducing the phonon dispersion curve of a beryllium single-crystal. PMID:26134800

  12. Neutron inelastic scattering measurements of low-energy phonons in the multiferroic BiFeO3

    SciTech Connect

    Schneeloch, John A.; Xu, Zhijun; Wen, Jinsheng; Gehring, P. M.; Stock, C.; Matsuda, Masaaki; Winn, Barry L.; Gu, Genda; Shapiro, Stephen M.; Birgeneau, R. J.; Ushiyama, T.; Yanagisawa, Y.; Tomioka, Y.; Ito, T.; Xu, Guangyong

    2015-02-10

    In this study, we present neutron inelastic scattering measurements of the low-energy phonons in single crystal BiFeO3. The dispersions of the three acoustic phonon modes (LA along [100], TA1 along [010], and TA2 along [110]) and two low-energy optic phonon modes (LO and TO1) have been mapped out between 300 and 700 K. Elastic constants are extracted from the phonon measurements. The energy linewidths of both TA phonons at the zone boundary clearly broaden when the system is warmed toward the magnetic ordering temperature TN=640 K. In conclusion, this suggests that the magnetic order and low-energy lattice dynamics in this multiferroic material are coupled.

  13. Neutron inelastic scattering measurements of low-energy phonons in the multiferroic BiFeO3

    DOE PAGESBeta

    Schneeloch, John A.; Xu, Zhijun; Wen, Jinsheng; Gehring, P. M.; Stock, C.; Matsuda, Masaaki; Winn, Barry L.; Gu, Genda; Shapiro, Stephen M.; Birgeneau, R. J.; et al

    2015-02-10

    In this study, we present neutron inelastic scattering measurements of the low-energy phonons in single crystal BiFeO3. The dispersions of the three acoustic phonon modes (LA along [100], TA1 along [010], and TA2 along [110]) and two low-energy optic phonon modes (LO and TO1) have been mapped out between 300 and 700 K. Elastic constants are extracted from the phonon measurements. The energy linewidths of both TA phonons at the zone boundary clearly broaden when the system is warmed toward the magnetic ordering temperature TN=640 K. In conclusion, this suggests that the magnetic order and low-energy lattice dynamics in thismore » multiferroic material are coupled.« less

  14. Inelastic Neutron Scattering and Molecular Dynamics Determination of the Interaction Potential in Liquid CD{sub 4}

    SciTech Connect

    Guarini, E.; Barocchi, F.

    2007-10-19

    Anisotropic interactions of liquid CD{sub 4} are studied in detail by comparison of inelastic neutron Brillouin scattering data with molecular dynamics simulations using up to four different models of the methane site-site potential. We demonstrate that the experimental dynamic structure factor S(Q,{omega}) acts as a highly discriminating quantity for possible interaction schemes. In particular, the Q evolution of the spectra enables a selective probing of the short- and medium-range features of the anisotropic potentials. We show that the preferential configuration of methane dimers at liquid densities can thus be discerned by analyzing the orientation-dependent model potential curves, in light of the experimental and simulation results.

  15. Quantum transport through a multilevel magnetic structure with multiple inelastic scattering in a magnetic field taken into account

    NASA Astrophysics Data System (ADS)

    Val'kov, V. V.; Aksenov, S. V.; Ulanov, E. A.

    2015-02-01

    We present a solution for the problem of quantum electron transport through a magnetic atom adsorbed inside a break junction with paramagnetic metal electrodes. In agreement with experimental data, it was assumed that the conduction electrons experience inelastic scattering by the adsorbate due to s-d(f)-exchange interaction. The Keldysh technique was employed to obtain a general expression describing a current through the multilevel structure at finite temperatures in terms of the nonequilibrium Green's function. The use of the atomic representation allowed to exactly account for the non-equidistant structure of the energy spectrum of a magnetic atom and to simplify substantially the application of the Wick theorem for construction of the nonequilibrium diagrammatic technique for the Hubbard operators. The calculation of the current-voltage characteristics of the magnetic adatom in the tunnel regime at low temperatures revealed the presence of regions with a negative differential conductance in a magnetic field.

  16. Resonant inelastic x-ray scattering study of charge excitations in La(2)CuO(4).

    PubMed

    Kim, Y J; Hill, J P; Burns, C A; Wakimoto, S; Birgeneau, R J; Casa, D; Gog, T; Venkataraman, C T

    2002-10-21

    We report a resonant inelastic x-ray scattering study of the dispersion relations of charge-transfer excitations in insulating La(2)CuO(4).. These data reveal two peaks, both of which show two-dimensional characteristics. The lowest energy excitation has a gap energy of approximately 2.2 eV at the zone enter, and a dispersion of approximately 1 eV. The spectral weight of this mode becomes dramatically smaller around (pi, pi). The second peak shows a smaller dispersion ( approximately 0.5 eV) with a zone-center energy of approximately 3.9 eV. We argue that these are both highly dispersive exciton modes damped by the presence of the electron-hole continuum.

  17. Inelastic X-ray Scattering Investigations of Lattice Dynamics in SmFeAsO1-xFy Superconductors

    SciTech Connect

    Hill, J.P.; Le Tacon, M.; Forrest, T.R.; Ruegg, Ch.; Bosak, A.; Noffsinger, J.; Walters, A.C.; Toulemonde, P.; Palenzona, A.; Zhigadlo, N.D.; Karpinski, J.; Krisch, M.; McMorrow, D.F.

    2010-05-23

    We report measurements of the phonon density of states as measured with inelastic x-ray scattering in SmFeAsO{sub 1-x}F{sub y} powders. An unexpected strong renormalization of phonon branches around 23 meV is observed as fluorine is substituted for oxygen. Phonon dispersion measurements on SmFeAsO{sub 1-x}F{sub y} single crystals allow us to identify the 21 meV A{sub 1g} in-phase (Sm,As) and the 26 meV B{sub 1g} (Fe,O) modes to be responsible for this renormalization, and may reaveal unusual electron-phonon coupling through the spin channel in iron-based superconductors.

  18. Communication: The H{sub 2}@C{sub 60} inelastic neutron scattering selection rule: Expanded and explained

    SciTech Connect

    Poirier, Bill

    2015-09-14

    Recently [M. Xu et al., J. Chem. Phys. 139, 064309 (2013)], an unexpected selection rule was discovered for the title system, contradicting the previously held belief that inelastic neutron scattering (INS) is not subject to any selection rules. Moreover, the newly predicted forbidden transitions, which emerge only in the context of coupled H{sub 2} translation-rotation (TR) dynamics, have been confirmed experimentally. However, a simple physical understanding, e.g., based on group theory, has been heretofore lacking. This is provided in the present paper, in which we (1) derive the correct symmetry group for the H{sub 2}@C{sub 60} TR Hamiltonian and eigenstates; (2) complete the INS selection rule, and show that the set of forbidden transitions is actually much larger than previously believed; and (3) evaluate previous theoretical and experimental results, in light of the new findings.

  19. Inelastic neutron scattering study of phonon density of states in nanostructured Si1 xGex thermoelectrics

    SciTech Connect

    Dhital, Chetan; Abernathy, Douglas L; Zhu, Gaohua; Ren, Zhifeng; Broido, D.; Wilson, Stephen D

    2012-01-01

    Inelastic neutron scattering measurements are utilized to explore relative changes in the generalized phonon density of states of nanocrystalline Si1 xGex thermoelectric materials prepared via ball-milling and hot-pressing techniques. Dynamic signatures of Ge clustering can be inferred from the data by referencing the resulting spectra to a density functional theoretical model assuming homogeneous alloying via the virtual-crystal approximation. Comparisons are also presented between as-milled Si nanopowder and bulk, polycrystalline Si where a preferential low-energy enhancement and lifetime broadening of the phonon density of states appear in the nanopowder. Negligible differences are however observed between the phonon spectra of bulk Si andhot-pressed, nanostructured Si samples suggesting that changes to the single-phonon dynamics above 4 meV play only a secondary role in the modified heat conduction of this compound.

  20. Probing single magnon excitations in Sr₂IrO₄ using O K-edge resonant inelastic x-ray scattering

    DOE PAGESBeta

    Liu, X.; Dean, M. P. M.; Liu, J.; Chiuzbaian, S. G.; Jaouen, N.; Nicolaou, A.; Yin, W. G.; Rayan Serrao, C.; Ramesh, R.; Ding, H.; et al

    2015-04-28

    Resonant inelastic X-ray scattering (RIXS) at the L-edge of transition metal elements is now commonly used to probe single magnon excitations. Here we show that single magnon excitations can also be measured with RIXS at the K-edge of the surrounding ligand atoms when the center heavy metal elements have strong spin-orbit coupling. This is demonstrated with oxygen K-edge RIXS experiments on the perovskite Sr₂IrO₄, where low energy peaks from single magnon excitations were observed. This new application of RIXS has excellent potential to be applied to a wide range of magnetic systems based on heavy elements, for which the L-edgemore » RIXS energy resolutions in the hard X-ray region is usually poor.« less

  1. Probing single magnon excitations in Sr₂IrO₄ using O K-edge resonant inelastic x-ray scattering

    SciTech Connect

    Liu, X.; Dean, M. P. M.; Liu, J.; Chiuzbaian, S. G.; Jaouen, N.; Nicolaou, A.; Yin, W. G.; Rayan Serrao, C.; Ramesh, R.; Ding, H.; Hill, J. P.

    2015-04-28

    Resonant inelastic X-ray scattering (RIXS) at the L-edge of transition metal elements is now commonly used to probe single magnon excitations. Here we show that single magnon excitations can also be measured with RIXS at the K-edge of the surrounding ligand atoms when the center heavy metal elements have strong spin-orbit coupling. This is demonstrated with oxygen K-edge RIXS experiments on the perovskite Sr₂IrO₄, where low energy peaks from single magnon excitations were observed. This new application of RIXS has excellent potential to be applied to a wide range of magnetic systems based on heavy elements, for which the L-edge RIXS energy resolutions in the hard X-ray region is usually poor.

  2. Vibrational Density of States of Strongly H-Bonded Interfacial Water: Insights from Inelastic Neutron Scattering and Theory

    SciTech Connect

    Wang, Hsiu-Wen; Dellostritto, Mark J; Kumar, Nitin; Kolesnikov, Alexander I; Kent, Paul R; Kubicki, James D.; Wesolowski, David J; Sofo, Jorge O.

    2014-01-01

    The vibrational dynamics of water and OH sorbed on SnO2 nanoparticles were probed with inelastic neutron scattering and analyzed with the assistance of ab-initio molecular dynamics. The combined analysis points to the existence of very strong hydrogen bonds at the surface with a formation enthalpy twice the average value for liquid water. This unusually large interaction results in (i) decoupling of the hydrated surface from the water system due to an epitaxially-induced screening layer, resulting in an apparent ice-like INS signal at multilayer coverage, (ii) splitting of OH wagging modes that can be used as an experimental indication of the strength of the surface hydrogen bonds, and (iii) high proton exchange rates and high degree of water dissociation at the interface. Our analysis provides general guidance into the tuning of surface hydrophobicity at the molecular level.

  3. Inelastic x-ray scattering measurements of phonon dispersion and lifetimes in PbTe1-x Se x alloys.

    PubMed

    Tian, Zhiting; Li, Mingda; Ren, Zhensong; Ma, Hao; Alatas, Ahmet; Wilson, Stephen D; Li, Ju

    2015-09-23

    PbTe1-x Se x alloys are of special interest to thermoelectric applications. Inelastic x-ray scattering determination of phonon dispersion and lifetimes along the high symmetry directions for PbTe1-x Se x alloys are presented. By comparing with calculated results based on the virtual crystal model calculations combined with ab initio density functional theory, the validity of virtual crystal model is evaluated. The results indicate that the virtual crystal model is overall a good assumption for phonon frequencies and group velocities despite the softening of transverse acoustic phonon modes along [1 1 1] direction, while the treatment of lifetimes warrants caution. In addition, phonons remain a good description of vibrational modes in PbTe1-x Se x alloys.

  4. Resonant inelastic X-ray scattering spectrometer with 25 meV resolution at the Cu K-edge

    PubMed Central

    Ketenoglu, Didem; Harder, Manuel; Klementiev, Konstantin; Upton, Mary; Taherkhani, Mehran; Spiwek, Manfred; Dill, Frank-Uwe; Wille, Hans-Christian; Yavaş, Hasan

    2015-01-01

    An unparalleled resolution is reported with an inelastic X-ray scattering instrument at the Cu K-edge. Based on a segmented concave analyzer, featuring single-crystal quartz (SiO2) pixels, the spectrometer delivers a resolution near 25 meV (FWHM) at 8981 eV. Besides the quartz analyzer, the performance of the spectrometer relies on a four-bounce Si(553) high-resolution monochromator and focusing Kirkpatrick–Baez optics. The measured resolution agrees with the ray-tracing simulation of an ideal spectrometer. The performance of the spectrometer is demonstrated by reproducing the phonon dispersion curve of a beryllium single-crystal. PMID:26134800

  5. Single transverse spin asymmetries in semi-inclusive deep inelastic scattering in a spin-1 diquark model

    NASA Astrophysics Data System (ADS)

    Kumar, Narinder; Dahiya, Harleen

    2015-04-01

    The observed results for the azimuthal single spin asymmetries (SSAs) of the proton, measured in the semi-inclusive deep inelastic scattering (SIDIS), can be explained by the final-state interaction (FSI) from the gluon exchange between the outgoing quark and the target spectator system. SSAs require a phase difference between two amplitudes coupling the target with opposite spins to the same final state. We have used the model of light front wave functions (LFWFs) consisting of a spin- system as a composite of a spin- fermion and a spin-1 vector boson to estimate the SSAs. The implications of such a model have been investigated in detail by considering different coupling constants. The FSIs also produce a complex phase which can be included in the LFWFs to calculate the Sivers and Boer-Mulders distribution functions of the nucleon.

  6. Surface Structure of Bi(111) from Helium Atom Scattering Measurements. Inelastic Close-Coupling Formalism

    PubMed Central

    2015-01-01

    Elastic and inelastic close-coupling (CC) calculations have been used to extract information about the corrugation amplitude and the surface vibrational atomic displacement by fitting to several experimental diffraction patterns. To model the three-dimensional interaction between the He atom and the Bi(111) surface under investigation, a corrugated Morse potential has been assumed. Two different types of calculations are used to obtain theoretical diffraction intensities at three surface temperatures along the two symmetry directions. Type one consists of solving the elastic CC (eCC) and attenuating the corresponding diffraction intensities by a global Debye–Waller (DW) factor. The second one, within a unitary theory, is derived from merely solving the inelastic CC (iCC) equations, where no DW factor is necessary to include. While both methods arrive at similar predictions for the peak-to-peak corrugation value, the variance of the value obtained by the iCC method is much better. Furthermore, the more extensive calculation is better suited to model the temperature induced signal asymmetries and renders the inclusion for a second Debye temperature for the diffraction peaks futile. PMID:26257838

  7. Measurement of the ratio {σ n}/{σ p} in inelastic muon-nucleon scattering at very low χ and Q2

    NASA Astrophysics Data System (ADS)

    Adams, M. R.; Aïd, S.; Anthony, P. L.; Baker, M. D.; Bartlett, J.; Bhatti, A. A.; Braun, H. M.; Busza, W.; Carroll, T. J.; Conrad, J. M.; Coutrakon, G.; Davisson, R.; Derado, I.; Dhawan, S. K.; Dougherty, W.; Dreyer, T.; Dziunikowska, K.; Eckardt, V.; Ecker, U.; Erdmann, M.; Eskreys, A.; Figiel, J.; Gebauer, H. J.; Geesaman, D. F.; Gilman, R.; Green, M. C.; Haas, J.; Halliwell, C.; Hanlon, J.; Hantke, D.; Hughes, V. W.; Jackson, H. E.; Jaffe, D. E.; Jancso, G.; Jansen, D. M.; Kaufman, S.; Kennedy, R. D.; Kirk, T.; Kobrak, H. G. E.; Krzywdzinski, S.; Kunori, S.; Lord, J. J.; Lubatti, H. J.; McLeod, D.; Magill, S.; Malecki, P.; Manz, A.; Melanson, H.; Michael, D. G.; Mohr, W.; Montgomery, H. E.; Morfin, J. G.; Nickerson, R. B.; O'Day, S.; Olkiewicz, K.; Osborne, L.; Papavassiliou, V.; Pawlik, B.; Pipkin, F. M.; Ramberg, E. J.; Röser, A.; Ryan, J. J.; Salvarani, A.; Schellman, H.; Schmitt, M.; Schmitz, N.; Schüler, K. P.; Seyerlein, H. J.; Skuja, A.; Snow, G. A.; Söldner-Rembold, S.; Steinberg, P. H.; Stier, H. E.; Stopa, P.; Swanson, R. A.; Talaga, R.; Tentindo-Repond, S.; Trost, H.-J.; Venkataramania, H.; Vidal, M.; Wilhelm, M.; Wilkes, J.; Wilson, Richard; Wittek, W.; Wolbers, S. A.; Zhao, T.; Fermilab E665 Collaboration

    1993-07-01

    We present results on the cross-section ratio for inelastic muon scattering on neutrons and protons as a function of Bjorken chi;. The data extend to χ values two orders of magnitude smaller than in previous measurements, down to 2×10 -5, for Q2>0.01 GeV 2. The ratio is consistent with unity throughout this new range.

  8. A crossed-beam study of the state-resolved dynamics of CH( X sup 2. Pi. )+D sub 2. I. The inelastic scattering channel

    SciTech Connect

    Macdonald, R.G.; Liu, K. )

    1990-08-15

    The state-to-state integral cross sections for the inelastic scattering of CH({ital X} {sup 2}{Pi}) and D{sub 2} to produce rotationally excited CH({ital X} {sup 2}{Pi}) product have been measured in a crossed-beam apparatus by the laser-induced fluorescence method. Two types of measurements were performed: (1) the translational energy dependence of an individual quantum state of the product and (2) the state distribution of the products at fixed and well-defined translational energy. For the inelastic scattering channel, the cross sections gradually increased from a dynamical threshold to a broad maximum and then slowly decreased as the translational energy increases. Evidence for multiple-impact rotational rainbows was found and a possible frequency-locking phenomenon between the two receding rotors resulted. Moderate orbital alignment was observed except for the highest rotational levels of the product. By comparing and contrasting the kinematically similar system CH({ital X} {sup 2}{Pi})+He, the influence of a strongly attractive potential energy surface on the inelastic scattering of CH+D{sub 2} was inferred. Combining the results of the inelastic scattering and the isotopic exchange channels (the following paper) provide an unprecedented look into the dynamics of collisions between CH({ital X} {sup 2}{Pi}) and D{sub 2}.

  9. Complete Electric and Magnetic Dipole Response of 208Pb from Zero-Degree Inelastic Proton Scattering

    NASA Astrophysics Data System (ADS)

    von Neumann-Cosel, P.

    2015-11-01

    Small-angle polarized proton scattering including 0° off 208Pb has been studied at the RCNP cyclotron with high energy resolution of the order of 25 keV (FWHM). The complete E1 strength distribution from 5 to 20 MeV could be extracted from the data and is found to agree well with available data. New E1 strength is found in the energy region above threshold inacessible in previous experiments. The total E1 polarizability as well as the properties of the pygmy dipole resonance could be determined with high precision providing important experimental constraints on the neutron skin thickness in 208Pb and the symmetry energy of neutron-rich matter. Additionally, information on the spin-M1 strength in 208Pb was obtained. Assuming dominance of the central spin-isospinflip part of the effective proton-nucleus interaction, the B(M1) transition strength can be derived. It corresponds well with data from electromagnetic probes indicating that the reaction can provide information on the poorly known spin-M1 resonance in heavy nuclei.

  10. Inelastic neutron scattering studies of Ge-76 and Se-76: relevance to neutrinoless double-beta decay

    SciTech Connect

    Crider, Ben; Peters, Erin; Ross, T.J.; McEllistrem, M; Prados-Estevez, F.; Allmond, James M; Vanhoy, J.R.; Yates, S.W.

    2015-01-01

    Inelastic neutron scattering measurements were performed at the University of Kentucky Accelerator Laboratory on enriched Ge-76 and Se-76 scattering samples. From measurements at incident neutron energies from 2.0 to 4.0 MeV, many new levels were identified and characterized in each nucleus; level lifetimes, transition probabilities, multipole mixing ratios, and other properties were determined. In addition, gamma-ray cross sections for the Ge-76(n,n'gamma) reaction were measured at neutron energies up to 5.0 MeV, with the goal of determining the cross sections of gamma rays in 2040-keV region, which corresponds to the region of interest in the neutrinoless double beta decay of Ge-76. Gamma rays from the three strongest branches from the 3952-keV level were observed, but the previously reported 2041-keV gamma ray was not. Population cross sections across the range of incident neutron energies were determined for the 3952-keV level, resulting in a cross section of similar to 0.1 mb for the 2041-keV branch using the previously determined branching ratios. Beyond this, the data from these experiments indicate that previously unreported gamma rays from levels in Ge-76 can be found in the 2039-keV region.

  11. Low-energy excitations and the fast process of polystyrene thin supported films studied by inelastic and quasielastic neutron scattering

    SciTech Connect

    Inoue, Rintaro; Kanaya, Toshiji; Nishida, Koji; Tsukushi, Itaru; Shibata, Kaoru

    2006-08-15

    We studied the low-energy excitations in the meV region as well as the picosecond fast process in polystyrene thin supported films using inelastic and quasielastic neutron scattering in a temperature range from 11 to 430 K, covering the bulk glass transition temperature T{sub g}. It was found that the mean square displacement decreased with the film thickness below and above the glass transition temperature T{sub g}, suggesting that the hardening occurs with decreasing the film thickness. Corresponding to the decrease in , it was also found that the density of phonon states G({omega}) decreased with film thickness. This decrease occurs mainly in the Debye mode while the contribution of the boson peak mode also decreases with the film thickness without changing the boson peak energy. As for the fast process, which appeared above at about 150 K as a quasielastic scattering, the fraction A{sub fast}(Q) decreased with the film thickness in a similar manner with the boson peak without changing the relaxation rate, suggesting a common origin for the boson peak and the fast process. These observations showing the hardening were well explained by assuming a hard dense layer at the interface, where the numbers of the boson peak mode as well as the fast process are less than the bulk state.

  12. Examination of higher-order twist contributions in parity-violating deep-inelastic electron-deuteron scattering

    NASA Astrophysics Data System (ADS)

    Mantry, Sonny; Ramsey-Musolf, Michael J.; Sacco, Gian Franco

    2010-12-01

    We show that parity-violating deep-inelastic scattering (PVDIS) of longitudinally polarized electrons from deuterium can in principle be a relatively clean probe of higher twist quark-quark correlations beyond the parton model. As first observed by Bjorken and Wolfenstein, the dominant contribution to the electron polarization asymmetry, proportional to the axial vector electron coupling, receives corrections at twist four from the matrix element of a single four-quark operator. We reformulate the Bjorken-Wolfenstein argument in a matter suitable for the interpretation of experiments planned at the Thomas Jefferson National Accelerator Facility (JLab). In particular, we observe that because the contribution of the relevant twist-four operator satisfies the Callan-Gross relation, the ratio of parity-violating longitudinal and transverse cross sections, RγZ, is identical to that for purely electromagnetic scattering, Rγ, up to perturbative and power-suppressed contributions. This result simplifies the interpretation of the asymmetry in terms of other possible novel hadronic and electroweak contributions. We use the results of MIT Bag Model calculations to estimate contributions of the relevant twist-four operator to the leading term in the asymmetry as a function of Bjorken x and Q2. We compare these estimates with possible leading twist corrections from violation of charge symmetry in the parton distribution functions.

  13. An infrared and inelastic neutron scattering spectroscopic investigation on the interaction of eta-alumina and methanol.

    PubMed

    McInroy, Alastair R; Lundie, David T; Winfield, John M; Dudman, Chris C; Jones, Peter; Parker, Stewart F; Taylor, Jon W; Lennon, D

    2005-08-21

    The industrially important interaction of methanol with an eta-alumina catalyst has been investigated by a combination of infrared spectroscopy (diffuse reflectance and transmission) and inelastic neutron scattering (INS) spectroscopy. The infrared and INS spectra together show that chemisorbed methoxy is the only surface species present. Confirmation of the assignments was provided by a periodic DFT calculation of methoxy on eta-alumina (110). The thermal conversion of adsorbed methoxy groups to form dimethylether was also followed by INS, with DFT calculations assisting assignments. An intense feature about 2600 cm(-1) was observed in the diffuse reflectance spectrum. This band is poorly described in the extensive literature on the alumina/methanol adsorption system and its observation raised the possibility of a new surface species existing on this particular catalyst surface. INS measurements established that the 2600 cm(-1) feature could be assigned to a combination band of the methyl rock with the methyl deformation modes. This assignment was reinforced by an analysis of the neutron scattering intensity at a particular energy as a function of momentum transfer, which confirmed this particular adsorbed methoxy feature to arise from a second order transition. Similar behaviour was observed in the model compound Al(OCH3)3. The anomalous infrared intensity of the 2600 cm(-1) peak in the diffuse reflectance spectrum is a consequence of the different absorption coefficients of the C-H stretch and the combination mode. The implications for catalyst studies are discussed.

  14. STUDY MAGNETIC EXCITATIONS IN DOPED TRANSITION METAL OXIDES USING INELASTIC NEUTRON SCATTERING

    SciTech Connect

    Dai, Pengcheng

    2014-02-18

    Understanding the interplay between magnetism and superconductivity continues to be a “hot” topic in modern condensed matter physics. The discovery of high-temperature superconductivity in iron-based materials in 2008 provided an unique opportunity to compare and contrast these materials with traditional high-Tc copper oxide superconductors. Neutron scattering plays an important role in determining the dynamical spin properties in these materials. This proposal is a continuation of previous DOE supported proposal. This report summarizes the final progress we have made over from May 2005 till Aug. 2013. Overall, we continue to carry out extensive neutron scattering experiments on Fe-based materials, focusing on understanding their magnetic properties. In addition, we have established a materials laboratory at UT that has allowed us to grow these superconductors. Because neutron scattering typically demands a large amount of samples, by growing these materials in our own laboratory, we can now pursuit neutron scattering experiments over the entire electronic phase diagram, focusing on regions of interests. The material synthesis laboratory at UT was established entirely with the support of DOE funding. This not only allowed us to carry out neutron scattering experiments, but also permit us to provide samples to other US/International collaborators for studying these materials.

  15. Direct inelastic scattering of N/sub 2/ from Ag(111). II. Orientation

    SciTech Connect

    Sitz, G.O.; Kummel, A.C.; Zare, R.N.; Tully, J.C.

    1988-08-15

    The orientation of the angular momentum of N/sub 2/ scattered from clean Ag(111) is determined by resonance-enhanced multiphoton ionization. The orientation is the net helicity or handedness of the sense of rotation, i.e., clockwise vs counterclockwise. The orientation of the scattered N/sub 2/ is measured along a direction perpendicular to the scattering plane. The degree and sign of the orientation is found to depend strongly on the final rotational quantum number J and on the final scattering angle. The results require that there are forces acting in the plane of the surface during the scattering. The observed behavior can be reproduced qualitatively by a conventional hard-cube, hard-ellipsoid model to which a tangential friction has been introduced to account for the in-plane forces. This produces a splitting of the rotational rainbow peak which leads to changes of sign of the orientation as a function of rotational quantum number. Thus, orientation measurements provide a unique probe of in-plane gas--surface forces.

  16. Gamma ray production cross section from energetic neutron inelastic scattering for methodical improvements in planetary gamma-ray spectroscopy

    SciTech Connect

    Castaneda, C.M.; Gearhart, R.; Sanii, B.; Englert, P.A.J.; Drake, D.M.; Reedy, R.C.

    1991-12-31

    Planetary Gamma ray spectroscopy can be used to chemically analyze the top soil from planets in future planetary missions. The production from inelastic neutron interaction plays an effective role in the determination on the C and H at the surface. The gamma ray production cross section from the strongest lines excited in the neutron bombardment of Fe have been measured by the use of a time analyzed quasi-mono-energetic neutron beam and a high purity germanium detector. The results from En=6.5, 32, 43, and 65 MeV are presented.

  17. Steric asymmetry and lambda-doublet propensities in state-to-state rotationally inelastic scattering of NO(2Π1/2) with He

    NASA Astrophysics Data System (ADS)

    de Lange, Marc J. L.; Stolte, Steven; Taatjes, Craig A.; Kłos, Jacek; Groenenboom, Gerrit C.; van der Avoird, Ad

    2004-12-01

    Relative integrated cross sections are measured for rotationally inelastic scattering of NO(2Π1/2), hexapole selected in the upper Λ-doublet level of the ground rotational state (j=0.5), in collisions with He at a nominal energy of 514 cm-1. Application of a static electric field E in the scattering region, directed parallel or antiparallel to the relative velocity vector v, allows the state-selected NO molecule to be oriented with either the N end or the O end towards the incoming He atom. Laser-induced fluorescence detection of the final state of the NO molecule is used to determine the experimental steric asymmetry, SA≡(σv↑↓E-σv↑↑E)/(σv↑↓E+σv↑↑E), which is equal to within a factor of (-1) to the molecular steric effect, Si→f≡(σHe→NO-σHe→ON)/(σHe→NO+σHe→ON). The dependence of the integral inelastic cross section on the incoming Λ-doublet component is also observed as a function of the final rotational (j'), spin-orbit (Ω'), and Λ-doublet (ɛ') state. The measured steric asymmetries are significantly larger than previously observed for NO-Ar scattering, supporting earlier proposals that the repulsive part of the interaction potential is responsible for the steric asymmetry. In contrast to the case of scattering with Ar, the steric asymmetry of NO-He collisions is not very sensitive to the value of Ω'. However, the Λ-doublet propensities are very different for [Ω=0.5(F1)→Ω'=1.5(F2)] and [Ω=0.5(F1)→Ω'=0.5(F1)] transitions. Spin-orbit manifold conserving collisions exhibit a propensity for parity conservation at low Δj, but spin-orbit manifold changing collisions do not show this propensity. In conjunction with the experiments, state-to-state cross sections for scattering of oriented NO(2Π) molecules with He atoms are predicted from close-coupling calculations on restricted coupled-cluster methods including single, double, and noniterated triple excitations [J. Klos, G. Chalasinski, M. T. Berry, R. Bukowski, and

  18. Numerical simulations for width fluctuations in compound elastic and inelastic scattering at low energies

    SciTech Connect

    Kawano, Toshihiko; Talou, Patrick

    2012-09-18

    The statistical theories - the Hauser-Feshbach model with the width fluctuation correction - play a central role in studying nuclear reactions in the fast energy region, hence the statistical model codes are essential for the nuclear data evaluations nowadays. In this paper, we revisit issues regarding the statistical model calculations in the fast energy range, such as the inclusion of the direct channels, and the energy averaged cross sections using different statistical assumptions. Although they have been discussed for a long time, we need more precise quantitative investigations to understand uncertainties coming from the models deficiencies in the fast energy range. For example, the partition of compound formation cross section into the elastic and inelastic channels depends on the elastic enhancement factor calculated from the statistical models. In addition, unitarity of S-matrix constrains this partition when the direct reactions are involved. Practically some simple assumptions, which many nuclear reaction model codes adopt, may work reasonably for the nuclear data evaluations. However, the uncertainties on the evaluated cross sections cannot go lower than the model uncertainty itself. We perform numerical simulations by generating the resonances using the R-matrix theory, and compare the energy (ensemble) averaged cross sections with the statistical theories, such as the theories of Moldauer, HRTW (Hofmann, Richert, Tepel, and Weidenmueller), KKM (Kawai-Kerman-McVoy), and GOE (Gaussian orthogonal ensemble).

  19. Formation of hydrogen atom in 2s state in proton-sodium inelastic scattering

    NASA Astrophysics Data System (ADS)

    Sabbah, A. Elkilany

    2015-03-01

    The inelastic collision of protons with sodium atoms are treated for the first time within the framework of the coupled-static and frozen core approximations. The method is used for calculating partial and total cross-sections with the assumption that only two channels (elastic and hydrogen formation in 2s state) are open. In each case, the calculations are carried out for seven values of the total angular momentum ℓ(0 ≤ ℓ ≤ 6). The target is described using the Clementi Roetti wave functions within the framework of the one valence electron model. We use Lipmann-Swinger equation to solve the derived equations of the problem, then apply an iterative numerical method to obtain the code of computer to calculate iterative partial cross-sections. This can be done through calculating the reactance matrix at different values of considered energies to obtain the transition matrix that gives partial and total cross sections. The present results for total hydrogen (2s state) formation cross sections are in agreement with results of other available ones in wide range of incident energy.

  20. Effects of Inelastic Collisions on Transport Cross Sections for Helium Atoms

    NASA Astrophysics Data System (ADS)

    Phelps, A. V.

    2002-10-01

    We review experimental and theoretical cross sections for elastic and inelastic collisions between ground state helium atoms from 0.01 eV to 10 keV. Pure elastic scattering is calculated using potentials from thermal transport coefficients, beam attenuation data, and theory. Inelastic collisions cause rapid decreases in measured elastic differential cross sections at angle times energy products greater than ˜ 3 degree keV for collision energies above 100 eV.(R. Morgenstern et al), J. Phys. B 4, L330 (1973); M. Barat et al, J. Phys. B 6, 1206 (1973); J. C. Brenot et al, Phys. Rev A 11, 1245 (1975). At these angles, the sum of the inelastic differential cross sections is roughly half theory for elastic scattering only. The inelastic collisions extrapolate to a 40 eV threshold and significantly decrease viscosity cross sections at higher energies. The change in total cross section is small. We correct the normalization of experimental ionization and excitation to theory.(V. Kempter, in The Physics of Electronic and Atomic Collisions), ed. by J. S. Risley and R. Geballe (U. Washington, Seattle, 1975) p. 327; J. P. Gauyacq, J. Phys. B 9, 3067 (1976).

  1. Vibrational properties and phonon anharmonicity in ZnS1-xSex: Inelastic neutron scattering, Raman scattering, X-ray diffraction measurements and lattice dynamical studies

    NASA Astrophysics Data System (ADS)

    Basak, Tista; Rao, Mala N.; Chaplot, S. L.; Salke, Nilesh; Rao, Rekha; Dhanasekaran, R.; Rajarajan, A. K.; Rols, S.; Mittal, R.; Jayakrishnan, V. B.; Sastry, P. U.

    2014-01-01

    Inelastic neutron scattering, Raman and X-ray diffraction measurements coupled with lattice dynamical calculations (employing a semi-empirical transferable potential model) have been carried out to gain a detailed understanding of the peculiar vibrational spectrum exhibited by the mixed crystal ZnS1-xSex. Raman scattering measurements performed over a varying range of temperature (100-800 K) and pressure (up to 13 GPa) have confirmed that the additional mode observed in the spectra are visible over the entire range of temperature and pressure. Correlation of the individual motions of atoms (obtained from computed total and partial phonon density of states) with the inelastic neutron scattering measurements (carried out over the entire Brillouin zone) have then indicated that the existence of the additional mode in ZnS1-xSex is due to the vibrations of the Se atom being in resonance with that of the S atom. Further, it has been shown that the presence of this additional mode can be tuned by varying the mass of the atom at the Se site. In addition, an analysis of bond-length distribution with increasing Se concentration have elucidated that bond-length spread is not responsible for the presence of the additional mode. An analysis of the peak shifts of the Raman modes with temperature and pressure indicate that the anharmonicity of the vibrational modes increases with increasing compositional disorder. This is attributed to the fact that increasing Se concentration gives rise to a distribution of bond-lengths in ZnS1-xSex, which is responsible for this compositional disorder induced anharmonicity. Our computations have thus revealed that mass of the anion is responsible for the presence of additional mode while bond-length distribution gives rise to the existence of compositional disorder induced anharmonicity in ZnS1-xSex. Further, it is observed that the contribution of explicit anharmonicity to the total anharmonicity becomes dominant at higher temperatures. This

  2. Nuclear Structure Relevant to Double-beta Decay: Studies of 76Ge and 76Se using Inelastic Neutron Scattering

    NASA Astrophysics Data System (ADS)

    Crider, Benjamin P.

    While neutrino oscillations indicate that neutrino flavors mix and that neutrinos have mass, they do not supply information on the absolute mass scale of the three flavors of neutrinos. Currently, the only viable way to determine this mass scale is through the observation of the theoretically predicted process of neutrinoless double-beta decay (0nubetabeta). This yet-to-be-observed decay process is speculated to occur in a handful of nuclei and has predicted half-lives greater than 1025 years. Observation of 0nubetabeta is the goal of several large-scale, multinational efforts and consists of detecting a sharp peak in the summed energies at the Q-value of the reaction. An exceptional candidate for the observation of 0nubetabeta is 76Ge, which offers an excellent combination of capabilities and sensitivities, and two such collaborations, MAJORANA and GERDA, propose tonne-scale experiments that have already begun initial phases using a fraction of the material. The absolute scale of the neutrino masses hinges on a matrix element, which depends on the ground-state wave functions for both the parent (76Ge) and daughter (76Se) nuclei in the 0nubetabeta decay and can only be calculated from nuclear structure models. Efforts to provide information on the applicability of these models have been undertaken at the University of Kentucky Accelerator Laboratory using gamma-ray spectroscopy following inelastic scattering reactions with monoenergetic, accelerator-produced fast neutrons. Information on new energy levels and transitions, spin and parity assignments, lifetimes, multipole mixing ratios, and transition probabilities have been determined for 76Se, the daughter of 76Ge 0nubetabeta, up to 3.0 MeV. Additionally, inaccuracies in the accepted level schemes have been addressed. Observation of 0nubetabeta requires precise knowledge of potential contributors to background within the region of interest, i.e., approximately 2039 keV for 76Ge. In addition to backgrounds

  3. Inelastic Scattering and Single and Double Charge Exchange Reactions Within the A=27 Isobaric Multiplet.

    NASA Astrophysics Data System (ADS)

    McKinzie, Matthew Gordon

    1995-01-01

    Angular distributions for the reactions ^{27}Al, ^{28 }Si(pi^{+/- },pi^{+/-} ) at T_pi = 180 MeV and an excitation function at theta_ {rm lab.} = 5^{ rm o} for the reaction ^{27}Al(pi^{+}, pi^{-})^{27}P were measured using the Energetic Pion Channel and Spectrometer at the Clinton P. Anderson Meson Physics Facility in Los Alamos, New Mexico. Angular distributions for the reaction ^{27}Al(n,p)^ {27}Mg were measured at T_ {rm N} = 198 MeV using the Medium Resolution Spectrometer at Canada's Tri-University Meson Facility in Vancouver, British Columbia. Multipole matrix elements were extracted in a macroscopic manner from the pion inelastic angular distributions using the distorted-wave impulse approximation and collective -model transition densities. Microscopic calculations of these extracted matrix elements and of the pion angular distributions were examined. Double charge exchange (DCX) excitation functions to the ^{27}P ground state and an excited state were measured at nine incident pion energies from T_pi = 100 to 293.4 MeV. The systematics of DCX excitation functions to low-lying states is reviewed in light of these data. Microscopic calculations of DCX for and near A = 27 are investigated. Double giant resonances in ^{27}P were observed at the three highest energies. The (n,p) charge exchange angular distributions were obtained for theta_{rm lab.} = 0^circ, 4^circ, 8^ circ, 12^circ, 18^circ and 24^ circ. The Gamow-Teller strength distribution was measured and compared to a microscopic calculation. The constant of proportionality between reduced transition probability and cross section (the unit cross section) was generalized and examined for configuration dependence. Data for higher spin-multipole isovector excitations are presented, including low-lying spin-isospin E2 strength and negative -parity giant resonances.

  4. Extracting paramagnon excitations from resonant inelastic x-ray scattering experiments

    NASA Astrophysics Data System (ADS)

    Lamsal, Jagat; Montfrooij, Wouter

    2016-06-01

    Resonant x-ray scattering experiments on high-temperature superconductors and related cuprates have revealed the presence of intense paramagnon scattering at high excitation energies, of the order of several hundred meV. The excitation energies appear to show very similar behavior across all compounds, ranging from magnetically ordered, via superconductors, to heavy fermion systems. However, we argue that this apparent behavior has been inferred from the data through model fitting which implicitly imposes such similarities. Using model fitting that is free from such restrictions, we show that the paramagnons are not nearly as well defined as has been asserted previously, and that some paramagnons might not represent propagating excitations at all. Our work indicates that the data published previously in the literature will need to be reanalyzed with proper models.

  5. The temperature dependence of inelastic light scattering from small particles for use in combustion diagnostic instrumentation

    NASA Technical Reports Server (NTRS)

    Cloud, Stanley D.

    1987-01-01

    A computer calculation of the expected angular distribution of coherent anti-Stokes Raman scattering (CARS) from micrometer size polystyrene spheres based on a Mie-type model, and a pilot experiment to test the feasibility of measuring CARS angular distributions from micrometer size polystyrene spheres by simply suspending them in water are discussed. The computer calculations predict a very interesting structure in the angular distributions that depends strongly on the size and relative refractive index of the spheres.

  6. Deep Inelastic Structure Functions from Electron Scattering on Hydrogen, Deuterium, and Iron at 0.6 GEV(2) <= Q('2) <= 30.0 GEV(2)

    NASA Astrophysics Data System (ADS)

    Whitlow, Larry W.

    1990-01-01

    We report the final results from experiment E140, a recent deep inelastic electron-deuterium and electron -iron scattering experiment at SLAC. In addition, we present the results of a combined global analysis of all SLAC deep inelastic electron-hydrogen and electron-deuterium cross section measurements between 1970 and 1983. Data from seven earlier experiments are re-radiatively corrected and normalized to experiment E140. We report extractions of R(x,Q^2) and F_2(x,Q ^2) for hydrogen and deuterium over the entire SLAC kinematic range:.06 <= x <=.90 and 0.6 <= Q^2 <= 30.0 (GeV^2). We find that R^{p} = R^{d}, as expected by QCD. Extracted values of R(x,Q^2) are significantly larger than predictions based on QCD and on QCD with the inclusion of kinematic target mass terms. This difference indicates that dynamical higher twist effects may be important in the SLAC kinematic range. A best fit empirical model of R(x,Q^2) is used to extract F_2 from each cross section measurement. These F_2 extractions are compared with F_2 data from EMC and BCDMS. Agreement is observed with EMC when the EMC data are multiplied by times 1.07. Agreement is observed with BCDMS over a limited range in x. The ratios of F_sp{2} {d}/F_sp{2}{p} are examined for Q^2 dependence. We observe a significant negative slope for x<= .6, and a significant positive slope above x>.7 , in excellent agreement with predictions based on QCD with the inclusion of kinematic target mass terms.

  7. ASPIN: An all spin scattering code for atom molecule rovibrationally inelastic cross sections

    NASA Astrophysics Data System (ADS)

    López-Durán, D.; Bodo, E.; Gianturco, F. A.

    2008-12-01

    We present in this work a new computational code for the quantum calculation of integral cross sections for atom-molecule (linear) scattering processes. The atom is taken to be structureless while the molecule can be in its singlet, doublet, or triplet spin states and can be treated as either a rigid rotor or a rovibrational target. All the relevant state-to-state integral cross sections, and their sums over final states, can be calculated with the present code, for which we also describe in detail the various component routines. Program summaryProgram title: ASPIN Catalogue identifier: AEBO_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEBO_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 99 596 No. of bytes in distributed program, including test data, etc.: 1 267 615 Distribution format: tar.gz Programming language: Fortran/MPI Computer: AMD OPTERON COMPUTING SYSTEMS, model TYAN GX28 (B2882) Operating system: SuSE LINUX Professional 9 RAM: 128 GB Classification: 2.6 External routines: LAPACK/BLAS Nature of problem: Scattering of a diatomic molecule in its Σ1, Σ2, or Σ3 spin states with an atom in its S1 state. Partial and integral cross sections. Solution method: The coupled channel equations that describe the scattering process are solved through the propagation of the reactance K matrix employing a modification of the Variable Phase Method [1-3]. Restrictions: Depending on the vib-rotational base used the problem may or may not fit into available RAM memory because all the runtime relevant quantities are stored on RAM memory instead of on disk. Additional comments: Both serial and parallel implementations of the program are provided. The CPC Librarian was not able to successfully run the parallel version. Running time: For simple and converged

  8. Covariant description of inelastic electron-deuteron scattering: predictions of the relativistic impulse approximation

    SciTech Connect

    J. Adam, Jr.; Franz Gross; Sabine Jeschonnek; Paul Ulmer; J.W. Van Orden

    2002-05-01

    Using the covariant spectator theory and the transversity formalism, the unpolarized, coincidence cross section for deuteron electrodisintegration, d(e, e'p)n, is studied. The relativistic kinematics are reviewed, and simple theoretical formulae for the relativistic impulse approximation (RIA) are derived and discussed. Numerical predictions for the scattering in the high Q{sup 2} region obtained from the RIA and five other approximations are presented and compared. We concluded that measurements of the unpolarized coincidence cross section and the asymmetry A{sub phi}, to an accuracy that will distinguish between different theoretical models, is feasible over most of the wide kinematic range accessible at Jefferson Lab.

  9. Inelastic electron scattering to negative parity states of /sup 24/Mg

    SciTech Connect

    Zarek, H.; Yen, S.; Pich, B.O.; Drake, T.E.; Williamson, C.F.; Kowalski, S.; Sargent, C.P.

    1984-05-01

    The electromagnetic form factors for the stronger transitions to negative parity states in /sup 24/Mg were measured for electron energies 90--280 MeV and scattering angles of 90/sup 0/ and 160/sup 0/. The isoscalar K/sup ..pi../ = 0/sup -/ and 3/sup -/ bands show form factors in agreement with open-shell random-phase approximation calculations, even though the parentages of these two bands are radically different. For the isovector negative parity states, a quenching of magnetic strength is observed; its origins are discussed.

  10. Inelastic p{sup 9}Be scattering and halo structure of the J{sup π} = 1/2{sup +} excited state of the {sup 9}Be nucleus

    SciTech Connect

    Zhusupov, M. A.; Ibraeva, E. T. Krassovitskiy, P. M.

    2015-01-15

    Differential cross sections for inelastic p{sup 9}Be scattering (to the J{sup α} = 1/2{sup +} level) were calculated on the basis of Glauber’s diffraction theory. The wave function for the {sup 9}Be nucleus in the three-particle 2αn model was used in this calculation. An expansion of this wave function in a series in Gaussian functions and the representation of the Glauber operator Ω in the form conjugate to the three-particle wave function make it possible to calculate analytically inelastic-scattering matrix elements. The differential cross section calculated by using the 2αn wave functions agrees well with available experimental data at E = 180 MeV.

  11. Medical applications of in vivo neutron inelastic scattering and neutron activation analysis: Technical similarities to detection of explosives and contraband

    NASA Astrophysics Data System (ADS)

    Kehayias, J. J.

    2001-07-01

    Nutritional status of patients can be evaluated by monitoring changes in elemental body composition. Fast neutron activation (for N and P) and neutron inelastic scattering (for C and O) are used in vivo to assess elements characteristic of specific body compartments. There are similarities between the body composition techniques and the detection of hidden explosives and narcotics. All samples have to be examined in depth and the ratio of elements provides a "signature" of the chemical of interest. The N/H and C/O ratios measure protein and fat content in the body. Similarly, a high C/O ratio is characteristic of narcotics and a low C/O together with a strong presence of N is a signature of some explosives. The available time for medical applications is about 20 min—compared to a few seconds for the detection of explosives—but the permitted radiation exposure is limited. In vivo neutron analysis is used to measure H, O, C, N, P, Na, Cl, and Ca for the study of the mechanisms of lean tissue depletion with aging and wasting diseases, and to investigate methods of preserving function and quality of life in the elderly.

  12. Role of adsorbed hydrogen species on ruthenium and molybdenum sulfides. Characterization by inelastic neutron scattering, thermoanalysis methods and model reactions

    SciTech Connect

    Lacroix, M.; Jobic, H.; Dumonteil, C.; Afanasiev, P.

    1996-12-31

    The interaction of hydrogen over unsupported MoS{sub 2} and RuS{sub 2} has been investigated as a function of the sulfur to metal ratio. On these solids the presence of sulfur deficient sites is required to generate an activity and to allow hydrogen chemisorption. The nature of the adsorbed species differs depending on the catalyst under investigation. On RuS{sub 2}, two types of hydrogen were evidenced by thermoflash desorption and inelastic neutron scattering: one was assigned to hydrogen adsorbed on surface sulfur anions while the other one is retained on coordinatively unsaturated ruthenium cations. By contrast, only SH groups were detected on MoS{sub 2}. ESR measurements have shown that a fraction of chemisorbed hydrogen induces a modification of the concentration of paramagnetic Mo(V) and Mo(III) species. Thus both solids behave differently towards an hydrogen atmosphere. RuS{sub 2} has a pseudometallic comportment whereas for MoS{sub 2} redox or acid base properties are involved.

  13. Structure of Alkali Borate Glasses at High Pressure: B and Li K-Edge Inelastic X-Ray Scattering Study

    SciTech Connect

    Lee, Sung Keun; Eng, Peter J.; Mao, Ho-kwang; Meng, Yue; Shu, Jinfu

    2008-06-16

    We report the first in situ boron K-edge inelastic x-ray scattering (IXS) spectra for alkali borate glasses (Li{sub 2}B{sub 4}O{sub 7}) at high pressure up to 30 GPa where pressure-induced coordination transformation from three-coordinated to four-coordinated boron was directly probed. Coordination transformation (reversible upon decompression) begins around 5 GPa and the fraction of four-coordinated boron increases with pressure from about 50% (at 1 atm) to more than 95% (at 30 GPa) with multiple densification mechanisms, evidenced by three distinct pressure ranges for (d{sup [4]}B/dP){sub T}. The lithium K-edge IXS spectrum for Li-borate glasses at 5 GPa shows IXS features similar to that at 1 atm, suggesting that the Li environment does not change much with pressure up to 5 GPa. These results provide improved understanding of the structure of low-z glass at high pressure.

  14. Magnetic model in multiferroic NdFe 3(BO 3)4 investigated by inelastic neutron scattering

    NASA Astrophysics Data System (ADS)

    Hayashida, S.; Soda, M.; Itoh, S.; Yokoo, T.; Ohgushi, K.; Kawana, D.; Rønnow, H. M.; Masuda, T.

    2015-08-01

    We performed inelastic neutron scattering measurements on single crystals of NdFe3(BO113 )4 to explore the magnetic excitations, to establish the underlying Hamiltonian, and to reveal the detailed nature of hybridization between the 4 f and 3 d magnetism. The observed spectra exhibiting a couple of key features, i.e., anticrossing of Nd and Fe excitations and anisotropy gap at the antiferromagnetic zone center, are explained by the magnetic model including spin interaction in the framework of weakly coupled Fe3 + chains, interaction between the Fe3 + and Nd3 + moments, and single-ion anisotropy derived from the Nd3 + crystal field. The combination of the measurements and calculations reveals that the hybridization between 4 f and 3 d magnetism propagates the local magnetic anisotropy of the Nd3 + moment to the Fe3 + network, leading to the determination of the bulk structure of both electric polarization and magnetic moment in the multiferroics of the spin-dependent metal-ligand hybridization type.

  15. Inelastic neutron scattering cross sections for Ge76 relevant to background in neutrinoless double- β decay experiments

    DOE PAGESBeta

    Crider, B. P.; Peters, E. E.; Allmond, J. M.; McEllistrem, M. T.; Prados-Estévez, F. M.; Ross, T. J.; Vanhoy, J. R.; Yates, S. W.

    2015-09-11

    The experimental signature in searches for the neutrinoless double- decay of 76Ge is a peak near 2039 keV in the spectrum. Given the low probability of the process, it is important that the background in this region be well understood. Moreover, inelastic scattering reactions with neutrons from muon-induced interactions and ( ,n) reactions in the surrounding materials or in the detector can provide contributions to the background. We also measured the production cross sections for rays from the 76Ge(n,n ) reaction in the 2039-keV region at incident neutron energies up to 4.9 MeV. In addition to determining that the crossmore » sections of a previously known 2040.7-keV ray from the 3952-keV level in 76 Ge are rather small, we find that a larger contribution arises from a 2037.5-keV ray which is attributed to a newly identified level at 3147 keV in 76Ge. Finally, a third contribution is also possible from another new level at 3577 keV. These results indicate that the 2039-keV region in 76Ge neutrinoless double- decay searches is more complex than was previously thought.« less

  16. Evaluation of the Doppler-Broadening of Gamma-Ray Spectra from Neutron Inelastic Scattering on Light Nuclei

    SciTech Connect

    Womble, Phillip C.; Barzilov, Alexander; Novikov, Ivan; Howard, Joseph; Musser, Jason

    2009-03-10

    Neutron-induced gamma-ray reactions are extensively used in the nondestructive analysis of materials and other areas where the information about the chemical composition of a substance is crucial. The common technique to find the intensity of the gamma ray is to fit gamma-ray line shape with an analytical function, for example, a Gaussian. However, the Gaussian fitting may fail if the gamma-ray peak is Doppler-broadened since this leads to the miscalculation of the area of the peak and, therefore, to misidentification of the material. Due to momentum considerations, Doppler-broadening occurs primarily with gamma rays from neutron-induced inelastic scattering reactions with light nuclei. The recoiling nucleus of interest must have excited states whose lifetimes are much smaller than the time of flight in the material. We have examined various light nuclei bombarded by 14 MeV neutrons to predict when the peak shape of a neutron-induced gamma ray emitted from these nuclei will be Doppler-broadened. We have found that nearly all the gamma rays from neutron-induced gamma-ray reactions on light elements (A<20) are Doppler-broadened with only a few exceptions. This means that utilization of resolution curves derived from isotopic sources or thermal neutron capture reactions have little value in the analysis.

  17. Identification of surface states on finely divided supported palladium catalysts by means of inelastic incoherent neutron scattering.

    PubMed

    Albers, Peter W; Krauter, Jürgen G E; Ross, D K; Heidenreich, Roland G; Köhler, Klaus; Parker, Stewart F

    2004-09-14

    The purpose of the present investigation was to utilize the inelastic incoherent neutron scattering (INS) technique to reveal changes at the surface of technical catalysts under the influence of hydrogen in gas/solid interactions and during chemical reactions in a liquid-phase process. The formation and the properties of supported palladium hydride and changes of the hydrogen-related surface chemistry of the corresponding activated carbon supports in 20% Pd/C catalysts after short-term and long-term hydrogen cycling at different hydrogen pressures and temperatures were studied. The spectra indicate that hydrogenation of the activated carbon support by hydrogen spillover occurs to, partly, give a material that strongly resembles a-C:H (amorphous hydrogenated carbon). Indications for different relaxation phenomena and long-range phase coherence inside of supported particles of palladium hydride compared to hydrogenated palladium black were obtained. A 5% Pd/C catalyst after use in C-C coupling reactions, the Heck reaction of bromobenzene and styrene to stilbenes, was also studied after subsequent solvent extraction. Evidence for a preferential adsorption and accumulation of cis-stilbene at the catalyst surface was obtained. INS allows identification of a certain isomer from a complex reaction mixture preferentially adsorbed at the surface of a finely divided industrial heterogeneous catalyst.

  18. Inelastic neutron scattering, Raman, vibrational analysis with anharmonic corrections, and scaled quantum mechanical force field for polycrystalline L-alanine

    NASA Astrophysics Data System (ADS)

    Williams, Robert W.; Schlücker, Sebastian; Hudson, Bruce S.

    2008-01-01

    A scaled quantum mechanical harmonic force field (SQMFF) corrected for anharmonicity is obtained for the 23 K L-alanine crystal structure using van der Waals corrected periodic boundary condition density functional theory (DFT) calculations with the PBE functional. Scale factors are obtained with comparisons to inelastic neutron scattering (INS), Raman, and FT-IR spectra of polycrystalline L-alanine at 15-23 K. Calculated frequencies for all 153 normal modes differ from observed frequencies with a standard deviation of 6 wavenumbers. Non-bonded external k = 0 lattice modes are included, but assignments to these modes are presently ambiguous. The extension of SQMFF methodology to lattice modes is new, as are the procedures used here for providing corrections for anharmonicity and van der Waals interactions in DFT calculations on crystals. First principles Born-Oppenheimer molecular dynamics (BOMD) calculations are performed on the L-alanine crystal structure at a series of classical temperatures ranging from 23 K to 600 K. Corrections for zero-point energy (ZPE) are estimated by finding the classical temperature that reproduces the mean square displacements (MSDs) measured from the diffraction data at 23 K. External k = 0 lattice motions are weakly coupled to bonded internal modes.

  19. Mapping the deformation in the "island of inversion": Inelastic scattering of 30Ne and 36Mg at intermediate energies

    NASA Astrophysics Data System (ADS)

    Doornenbal, P.; Scheit, H.; Takeuchi, S.; Aoi, N.; Li, K.; Matsushita, M.; Steppenbeck, D.; Wang, H.; Baba, H.; Ideguchi, E.; Kobayashi, N.; Kondo, Y.; Lee, J.; Michimasa, S.; Motobayashi, T.; Poves, A.; Sakurai, H.; Takechi, M.; Togano, Y.; Yoneda, K.

    2016-04-01

    The transition strengths of the first-excited 2+ states and deformation lengths of the nuclei 30Ne and 36Mg were determined via Coulomb- and nuclear-force-dominated inelastic scattering at intermediate energies. Beams of these exotic nuclei were produced at the RIKEN Radioactive Isotope Beam Factory and were incident on lead and carbon targets at energies above 200 MeV/u . Absolute excitation cross sections on the lead target yielded reduced transition probabilities of 0.0277(79) and 0.0528(121) e2b2 , while the measurements with the carbon target revealed nuclear deformation lengths of δN=1.98 (11) and 1.93(11) fm for 30Ne and 36Mg, respectively. Corresponding quadrupole deformation parameters of β2˜0.5 from the two probes were found comparable in magnitude, showing no indication for a reduction in deformation along isotopic and isotonic chains from 32Mg towards the neutron drip-line. Comparisons to shell-model calculations illustrate the importance of neutron excitations across the N =20 shell for 30Ne and suggest that shallow maximums of collectivity may occur around N =22 and 24 along the neon and magnesium isotopic chains, respectively.

  20. Inelastic neutron scattering study and magnetic excitations on the low-dimensional antiferromagnet α - Cu2V2O7

    NASA Astrophysics Data System (ADS)

    Gitgeatpong, Ganatee; Zhao, Yang; Qiu, Yiming; Matan, Kittiwit

    Magnetic excitations of the low-dimensional antiferromagnet α - Cu2V2O7 have been investigated using inelastic neutron scattering. The study reveals unusual commensurate splitting of magnetic excitation branches centered at a wave vector (0, +/- δ , 0) with δ = 0.25 away from a magnetic zone center, where a magnetic Bragg peak is observed. The energy gap of 0.75 meV at (0, +/- δ , 0) was found to decrease as a function of temperature and the magnetic excitations become diffusive and disappear above 35 K coincident with TN = 33.4 K. A recent experiment at the Multi Axis Crystal Spectrometer, MACS, to map the excitations over a large momentum space clearly shows the splitting of the dispersion at most of the allowed magnetic reflections. This commensurate splitting of the spin-wave-type excitations without the magnetic Bragg reflections at the same commensurate wave vectors has not yet been previously observed and remains unexplained. In the presentation, the experimental data will be shown and the possible explanation will also be discussed.

  1. Elastic and Inelastic Neutron Scattering with a C7LYC Array

    NASA Astrophysics Data System (ADS)

    Wilson, G. L.; Brown, T.; Chowdhury, P.; Doucet, E.; Lister, C. J.; D'Olympia, N.; Devlin, M.; Mosby, S.

    2015-10-01

    A scintillator array of 16 1'' ×1'' Cs2LiYCl6 (CLYC) detectors has been commissioned for low energy nuclear science. Standard CLYC crystals detect both gamma rays and neutrons rays with excellent pulse shape discrimination, with thermal neutrons detected via the 6Li(n, α)t reaction. Our discovery of spectroscopy-grade response of CLYC for fast neutrons via the 35Cl(n,p) reaction, with a pulse height resolution of under 10 % in the < 8 MeV range, led to our present array of 7Li enriched C7LYC detectors, where the large thermal neutron response is essentially eliminated. While the intrinsic efficiency of C7LYC for fast neutron detection is low, the array can be placed near the target since a long TOF arm is no longer needed for neutron energy measurement, thus recovering efficiency through increased solid angle coverage. The array was recently deployed at Los Alamos to test its capability in measuring differential scattering cross sections as a function of energy for 56Fe and 238U. The incident energy from a white neutron source was measured via TOF, and the scattered neutron energy via the pulse height. Techniques, analysis and first results will be discussed. Supported by the NNSA Stewardship Science Academic Alliance Program under Grant DE-NA00013008.

  2. Collimating Montel mirror as part of a multi-crystal analyzer system for resonant inelastic X-ray scattering.

    PubMed

    Kim, Jungho; Shi, Xianbo; Casa, Diego; Qian, Jun; Huang, XianRong; Gog, Thomas

    2016-07-01

    Advances in resonant inelastic X-ray scattering (RIXS) have come in lockstep with improvements in energy resolution. Currently, the best energy resolution at the Ir L3-edge stands at ∼25 meV, which is achieved using a diced Si(844) spherical crystal analyzer. However, spherical analyzers are limited by their intrinsic reflection width. A novel analyzer system using multiple flat crystals provides a promising way to overcome this limitation. For the present design, an energy resolution at or below 10 meV was selected. Recognizing that the angular acceptance of flat crystals is severely limited, a collimating element is essential to achieve the necessary solid-angle acceptance. For this purpose, a laterally graded, parabolic, multilayer Montel mirror was designed for use at the Ir L3-absorption edge. It provides an acceptance larger than 10 mrad, collimating the reflected X-ray beam to smaller than 100 µrad, in both vertical and horizontal directions. The performance of this mirror was studied at beamline 27-ID at the Advanced Photon Source. X-rays from a diamond (111) monochromator illuminated a scattering source of diameter 5 µm, generating an incident beam on the mirror with a well determined divergence of 40 mrad. A flat Si(111) crystal after the mirror served as the divergence analyzer. From X-ray measurements, ray-tracing simulations and optical metrology results, it was established that the Montel mirror satisfied the specifications of angular acceptance and collimation quality necessary for a high-resolution RIXS multi-crystal analyzer system. PMID:27359136

  3. Collimating Montel mirror as part of a multi-crystal analyzer system for resonant inelastic X-ray scattering.

    PubMed

    Kim, Jungho; Shi, Xianbo; Casa, Diego; Qian, Jun; Huang, XianRong; Gog, Thomas

    2016-07-01

    Advances in resonant inelastic X-ray scattering (RIXS) have come in lockstep with improvements in energy resolution. Currently, the best energy resolution at the Ir L3-edge stands at ∼25 meV, which is achieved using a diced Si(844) spherical crystal analyzer. However, spherical analyzers are limited by their intrinsic reflection width. A novel analyzer system using multiple flat crystals provides a promising way to overcome this limitation. For the present design, an energy resolution at or below 10 meV was selected. Recognizing that the angular acceptance of flat crystals is severely limited, a collimating element is essential to achieve the necessary solid-angle acceptance. For this purpose, a laterally graded, parabolic, multilayer Montel mirror was designed for use at the Ir L3-absorption edge. It provides an acceptance larger than 10 mrad, collimating the reflected X-ray beam to smaller than 100 µrad, in both vertical and horizontal directions. The performance of this mirror was studied at beamline 27-ID at the Advanced Photon Source. X-rays from a diamond (111) monochromator illuminated a scattering source of diameter 5 µm, generating an incident beam on the mirror with a well determined divergence of 40 mrad. A flat Si(111) crystal after the mirror served as the divergence analyzer. From X-ray measurements, ray-tracing simulations and optical metrology results, it was established that the Montel mirror satisfied the specifications of angular acceptance and collimation quality necessary for a high-resolution RIXS multi-crystal analyzer system.

  4. Excitation of the 4d shell in Sb, Te, and BaF2 with inelastic electron scattering: Collective or single particle?

    NASA Astrophysics Data System (ADS)

    Franck, Carl; Schnatterly, S. E.

    1982-06-01

    Simple models suggest that the momentum-transfer (q) dependence of inelastic electron scattering is sensitive to the difference between collective and single-particle behavior in atomic dynamics. We measured the energy centroid of the 4d continuum peak for 0

  5. Measurement of “pretzelosity” asymmetry of charged pion production in semi-inclusive deep inelastic scattering on a polarized He3 target

    DOE PAGESBeta

    Zhang, Y.; Qian, X.; Allada, K.; Dutta, C.; Huang, J.; Katich, J.; Wang, Y.; Aniol, K.; Annand, J. R. M.; Averett, T.; et al

    2014-11-24

    An experiment to measure single-spin asymmetries in semi-inclusive production of charged pions in deep-inelastic scattering on a transversely polarized ³He target was performed at Jefferson Lab in the kinematic region of 0.16 < x < 0.35 and 1.4 < Q² < 2.7 GeV². Our results show that both π± on 3He and on neutron pretzelosity asymmetries are consistent with zero within experimental uncertainties.

  6. Simultaneous extraction of transversity and Collins functions from new semi-inclusive deep inelastic scattering and e{sup +}e{sup -} data

    SciTech Connect

    Anselmino, Mauro; Boglione, Mariaelena; D'Alesio, Umberto; Melis, Stefano; Murgia, Francesco; Prokudin, Alexei

    2013-05-01

    We present a global re-analysis of the most recent experimental data on azimuthal asymmetries in semi-inclusive deep inelastic scattering, from the HERMES and COMPASS Collaborations, and in e{sup +}e{sup -} {yields} h{sub 1} h{sub 2} X processes, from the Belle Collaboration. The transversity and the Collins functions are extracted simultaneously, in the framework of a revised global analysis in which a new parameterisation of the unknown functions is also tested.

  7. [ital Q][sup 2] dependence of the average squared transverse energy of jets in deep-inelastic muon-nucleon scattering with comparison to perturbative QCD predictions

    SciTech Connect

    Adams, M.R.; Arndotied, S.; Anthony, P.L.; Baker, M.D.; Bartlett, J.; Bhatti, A.A.; Braun, H.M.; Busza, W.; Conrad, J.M.; Coutrakon, G.; Davisson, R.; Derado, I.; Dhawan, S.K.; Dougherty, W.; Dreyer, T.; Dziunikowska, K.; Eckardt, V.; Ecker, U.; Erdmann, M.; Eskreys, A.; Figiel, J.; Gebauer, H.J.; Geesaman, D.F.; Gilman, R.; Green, M.C.; Haas, J.; Halliwell, C.; Hanlon, J.; Hantke, D.; Hughes, V.W.; Jackson, H.E.; Jaffe, D.E.; Jancso, G.; Jansen, D.M.; Kaufman, S.; Kennedy, R.D.; Kirk, T.; Kobrak, H.G.E.; Krzywdzinski, S.; Kunori, S.; Lord, J.J.; Lubatti, H.J.; McLeod, D.; Magill, S.; Malecki, P.; Manz, A.; Melanson, H.; Michael, D.G.; Mohr, W.; Montgomery, H.E.; Morfin, J.G.; Nickerson, R.B.; O'Day, S.; Olkiewicz, K.; Osborne, L.; Papavassiliou, V.; Pawlik, B.; Pipkin, F.M.; Ramberg, E.J.; Roeser, A.; Ryan, J.J.; Salgado, C.W.; Salvarani, A.; Schellman, H.; Schmitt, M.; Schmitz, N.; Schueler, K.P.; Skuja, A.; Snow, G.A.; Soeldner-Rembold, S.; Steinberg, P.H.; Stier, H.E.; Stopa, P.; S

    1994-01-24

    The average squared transverse energy of jets in deep-inelastic muon-nucleon scattering is measured as a function of the momentum transfer squared ([ital Q][sup 2]), in the range 3[lt][ital Q][sup 2][lt]25 GeV[sup 2]. Perturbative QCD predicts that the average squared parton transverse energy will depend upon the strong coupling constant ([alpha][sub [ital S

  8. Study of deep inelastic scattering of polarized electrons off polarized deuterons

    SciTech Connect

    Kuriki, M.

    1996-03-01

    This thesis describes a 29GeV electron - nucleon scattering experiment carried out at Stanford Linear Accelerator Center (SLAC). Highly polarized electrons are scattered off a polarized ND{sub 3} target. Scattered electrons are detected by two spectrometers located in End Station A (ESA) at angles of 4.5{degrees} and 7{degrees} with respect to the beam axis. We have measured the spin structure function g{sub 1} of deuteron over the range of 0.029 < x < 0.8 and 1. 0 < Q{sup 2} < 12.0(GeV/c){sup 2}. This integral indicates a discrepancy of more than three standard deviations from the prediction of the Ellis-Jaffe sum rule, 0.068{+-}0.005 at Q{sup 2} = 3.0(GeV/c){sup 2} while our result of g{sub 1}{sup d} in good agreement with SMC results. Combined with g{sub 1} of the proton, the measurement of {integral}{sub 0}{sup 1}(g{sub 1}{sup d}-g{sub 1}{sup n}) is 0.169{+-}0.008. We also obtained the strong coupling constant at Q{sup 2} = 3.0(GeV/c){sup 2} to be 0.417{sub -0.110}{sup +0.086}, using the power correction for the sum rule up to third order of {alpha}{sub s}. This result is in agreement with the strong coupling constant {alpha}{sub s}(Q{sup 2}) = 3.0(GeV/c{sup 2}) obtained from various experiments. Using our deuteron results and the axial vector couplings of hyperon decays, the total quark polarization along the nucleon spin is found to be 0.286{+-}.055, implying that quarks carry only 30% of the nucleon spin. The strange sea quark polarization is also determined to be -0.101 {+-} .023. These measurements are in agreement with other experiments and provide the world`s most precise measurement of these quark polarizations. 80 refs., 151 figs., 23 tabs.

  9. Time reversal odd fragmentation functions in semi-inclusive deep inelastic lepton-hadron scattering

    SciTech Connect

    Mulders, P.J.; Levelt, J.

    1994-04-01

    In semi-inclusive scattering of polarized leptons from unpolarized hadrons, one can measure a time reversal odd structure function. It shows up as a sin({phi}) asymmetry of the produced hadrons. This asymmetry can be expressed as the product of a twist-three {open_quotes}hadron {r_arrow} quark{close_quotes} profile function and a time reversal odd twist-two {open_quotes}quark {r_arrow} hadron{close_quotes} fragmentation function. This fragmentation function can only be measured for nonzero transverse momenta of the produced hadron. Its appearance is a consequence of final state interactions between the produced hadron and the rest of the final state.

  10. Collision dynamics of symmetric top molecules: A comparison of the rotationally inelastic scattering of CD{sub 3} and ND{sub 3} with He

    SciTech Connect

    Tkáč, Ondřej; Orr-Ewing, Andrew J.; Dagdigian, Paul J.; Alexander, Millard H.; Onvlee, Jolijn; Avoird, Ad van der

    2014-04-07

    We compare rotationally inelastic scattering of deuterated methyl radicals (CD{sub 3}) and ammonia (ND{sub 3}) in collisions with helium using close-coupling quantum-mechanical scattering calculations performed with ab initio potential energy surfaces (PESs). The theoretical methods have been rigorously tested against angle-resolved experimental measurements obtained using crossed molecular beam apparatuses in combination with velocity map imaging [O. Tkáč, A. G. Sage, S. J. Greaves, A. J. Orr-Ewing, P. J. Dagdigian, Q. Ma, and M. H. Alexander, Chem. Sci. 4, 4199 (2013); O. Tkáč, A. K. Saha, J. Onvlee, C.-H. Yang, G. Sarma, C. K. Bishwakarma, S. Y. T. van de Meerakker, A. van der Avoird, D. H. Parker, and A. J. Orr-Ewing, Phys. Chem. Chem. Phys. 16, 477 (2014)]. Common features of the scattering dynamics of these two symmetric top molecules, one closed-shell and the other an open-shell radical, are identified and discussed. Two types of anisotropies in the PES influence the interaction of an atom with a nonlinear polyatomic molecule. The effects of these anisotropies can be clearly seen in the state-to-state integral cross sections out of the lowest CD{sub 3} rotational levels of each nuclear spin symmetry at a collision energy of 440 cm{sup −1}. Similarities and differences in the differential cross sections for the ND{sub 3}–He and CD{sub 3}–He systems can be linked to the coupling terms derived from the PESs which govern particular initial to final rotational level transitions.

  11. High-Energy-Resolution Inelastic Electron and Proton Scattering and the Multiphonon Nature of Mixed-Symmetry 2{sup +} States in {sup 94}Mo

    SciTech Connect

    Burda, O.; Kuhar, M.; Lenhardt, A.; Neumann-Cosel, P. von; Ponomarev, V. Yu.; Richter, A.; Wambach, J.; Botha, N.; Fearick, R. W.; Carter, J.; Sideras-Haddad, E.; Foertsch, S. V.; Neveling, R.; Smit, F. D.; Fransen, C.; Fujita, H.; Holt, J. D.; Pietralla, N.; Scholten, O.

    2007-08-31

    High-energy-resolution inelastic electron scattering (at the S-DALINAC) and proton scattering (at iThemba LABS) experiments permit a thorough test of the nature of proposed one- and two-phonon symmetric and mixed-symmetric 2{sup +} states of the nucleus {sup 94}Mo. The combined analysis reveals the one-phonon content of the mixed-symmetry state and its isovector character suggested by microscopic nuclear model calculations. The purity of two-phonon 2{sup +} states is extracted.

  12. Neutron capture and inelastic scattering cross sections for {sup 186}Os, {sup 187}Os, and {sup 189}Os and the Re-Os chronology

    SciTech Connect

    Segawa, M.; Nagai, Y.; Masaki, T.; Temma, Y.; Shima, T.; Mishima, K.; Igashira, M.; Goriely, S.; Koning, A.; Hilaire, S.

    2008-05-21

    We measured the neutron capture cross sections of {sup 186,187,189}Os taking for the first time their pulse height spectra for neutrons between 5 and 90 keV by means of an anti-Compton NaI(Tl) spectrometer. The neutron inelastic scattering cross section for {sup 187}Os as well as the neutron elastic scattering cross sections for {sup 186,187}Os were also observed with use of {sup 6}Li-glass scintillation detectors with a small systematic uncertainty.

  13. Theory of low energy excitations in resonant inelastic x-ray scattering for rare-earth systems: Yb compounds as typical examples

    NASA Astrophysics Data System (ADS)

    Kotani, A.

    2011-04-01

    Theoretical predictions are given for low energy excitations, such as crystal field excitations and Kondo resonance excitations, to be detected by high-resolution measurements of resonant inelastic x-ray scattering (RIXS) of rare-earth materials with Yb compounds as typical examples. Crystal field excitations in the Yb 3d RIXS of a Yb3+ ion in the cubic crystal field are formulated, and the calculation of RIXS spectra for YbN is done. Kondo resonance excitations revealed in the Yb 3d RIXS spectra are calculated for mixed-valence Yb compounds, Yb1-xLuxAl3, in the leading term approximation of the 1/Nf expansion method with a single impurity Anderson model. It is emphasized that the high-resolution RIXS with polarization dependence is a powerful tool to study the crystal field levels together with their symmetry and also the Kondo bound state in rare-earth compounds. Some in-depth discussions are given on the polarization effects of RIXS, including 4d and 2p RIXS spectra, the coherence effect of the Kondo bound states, and the importance of the high-resolution RIXS spectra for condensed matter physics under extreme conditions.

  14. Combined inelastic neutron scattering and solid-state DFT study of dynamics of hydrogen atoms in trioctahedral 1 M phlogopite

    NASA Astrophysics Data System (ADS)

    Smrčok, L'ubomír; Kolesnikov, Alexander I.; Rieder, Milan

    2012-10-01

    Inelastic neutron scattering (INS) was used to study the vibrational dynamics of the hydrogen atoms in natural trioctahedral phlogopite, K0.93Na0.03(Mg2.47Fe0.22Al0.16Fe0.04Tl0.06)[Si2.84Al1.16]O10OH1.71F0.28Cl0.01, within the 50-1,000 cm-1 energy range. The INS spectra collected using direct geometry spectrometer SEQUOIA (ORNL) were interpreted by means of the solid-state DFT calculations covering both normal mode analysis and molecular dynamics. To optimize the structure and to calculate the vibrational modes under harmonic approximation, both a hybrid PBE0 and the AM05 functional were used, while the molecular dynamics calculations (60 ps/1 fs) were performed only with the computationally less-demanding AM05 functional. The main contributions to the dominant band within ~750-550 cm-1 are symmetric and antisymmetric Mg-O-H bending modes, overlapping with the skeletal stretching and bending modes causing weaker secondary movements of H atoms of inner hydroxyl groups. Signatures of the Mg-O-H bending modes appear down to ~400 cm-1, where a region of octahedra deformation modes starts. These deformations cause just shallow movements of the hydrogen atoms and are mirrored by the modes with close vibrational energies. The region from ~330 cm-1 down to the low-energy end of the spectrum portrays induced vibrations of the H atoms caused by deformation of individual polyhedra, translational vibrations of the parts of the 2:1 layer relative one to another, and librational and translational vibrations of the layer. The main difference between the INS spectrum of dioctahedral Al-muscovite and trioctahedral Mg-phlogopite is that the Mg-O-H modes are all assigned to in-plane vibrations of the respective hydrogen atoms.

  15. Microfocusing options for the inelastic X-ray scattering beamline at sector 3 of the Advanced Photon Source.

    PubMed

    Alsmadi, A M; Alatas, A; Zhao, J Y; Hu, M Y; Yan, L; Alp, E E

    2014-05-01

    Synchrotron radiation from third-generation high-brilliance storage rings is an ideal source for X-ray microbeams. The aim of this paper is to describe a microfocusing scheme that combines both a toroidal mirror and Kirkpatrick-Baez (KB) mirrors for upgrading the existing optical system for inelastic X-ray scattering experiments at sector 3 of the Advanced Photon Source. SHADOW ray-tracing simulations without considering slope errors of both the toroidal mirror and KB mirrors show that this combination can provide a beam size of 4.5 µm (H) × 0.6 µm (V) (FWHM) at the end of the existing D-station (66 m from the source) with use of full beam transmission of up to 59%, and a beam size of 3.7 µm (H) × 0.46 µm (V) (FWHM) at the front-end of the proposed E-station (68 m from the source) with a transmission of up to 52%. A beam size of about 5 µm (H) × 1 µm (V) can be obtained, which is close to the ideal case, by using high-quality mirrors (with slope errors of less than 0.5 µrad r.m.s.). Considering the slope errors of the existing toroidal and KB mirrors (5 and 2.9 µrad r.m.s., respectively), the beam size grows to about 13.5 µm (H) × 6.3 µm (V) at the end of the D-station and to 12.0 µm (H) × 6.0 µm (V) at the front-end of the proposed E-station. The simulations presented here are compared with the experimental measurements that are significantly larger than the theoretical values even when slope error is included in the simulations. This is because of the experimental set-up that could not yet be optimized.

  16. Inelastic deformation and dislocation structure of a nickel alloy - Effects of deformation and thermal histories

    NASA Technical Reports Server (NTRS)

    Chan, K. S.; Page, R. A.

    1988-01-01

    Inelastic deformation behavior of the cast Ni-base alloy, B1900 + Hf, was investigated using data from step-temperature tensile tests and thermomechanical cyclic tests in the temperature ranges 538-760 C and 760-982 C. The deformation results were correlated with the dislocation structures of deformed specimens, identified by TEM. It was found that, in the 760-982 C temperature range, there are no thermal history effects in the inelastic deformation behavior of B1900 + Hf. In the 538-760 range, anomalous cyclic hardening and, possibly, thermal history effects were observed in thermomechanically deformed alloy, caused by sessile (010) dislocations in the gamma-prime phase.

  17. Resonant inelastic x-ray scattering of CeB[subscript 6] at the Ce L[subscript 1]- and L[subscript 3]-edges

    SciTech Connect

    Liu, Lijia; Sham, Tsun-Kong; Hayashi, Hisashi; Kanai, Noriko; Takehara, Yuki; Kawamura, Naomi; Mizumaki, Masaichiro; Gordon, Robert A.

    2012-11-01

    We report a resonant inelastic x-ray scattering (RIXS) study of crystalline CeB{sub 6}. Ce L{sub {alpha}1,2} RIXS was measured with excitation energies resonant with the Ce L{sub 3}-edge. A lifetime-broadening suppressed x-ray absorption near-edge structure (LBS-XANES), which successfully reproduced the L{sub {alpha}1,2} RIXS spectra over wide ranges of excitation and emission energies, was simulated using the SIM-RIXS program. A pre-edge structure in the LBS-XANES can be resolved, and many-body effects were suggested in the L{sub {alpha}1,2} RIXS around the Ce L{sub 3}-edge energy. No convincing signs of Ce (II) or Ce (IV) states were observed in the LBS-XANES. Ce L{sub {gamma}4} RIXS was measured at 302 K and 28 K with excitation energies across the Ce L{sub 1}-edge. The interactions of p-valence electrons between Ce and B{sub 6} were found to be considerably small, regardless of temperature. Thus, the electronic state of CeB{sub 6} was concluded to be suitably described as a nominally Ce(4f{sup 1}){sup 3+}(e{sup -})(B{sub 6}){sup 2-} system with some hybridization among all valence orbitals of Ce and B.

  18. High-Q{sup 2} neutral current cross sections in e{sup +}p deep inelastic scattering at {radical}(s)=318 GeV

    SciTech Connect

    2004-09-01

    Cross sections for e{sup +}p neutral current deep inelastic scattering have been measured at a center-of-mass energy of {radical}(s)=318 GeV with the ZEUS detector at HERA using an integrated luminosity of 63.2 pb{sup -1}. The double-differential cross section, d{sup 2}{sigma}/dxdQ{sup 2}, is presented for 200 GeV{sup 2}200 GeV{sup 2}. The effect of Z-boson-exchange is seen in d{sigma}/dx measured for Q{sup 2}>10 000 GeV{sup 2}. The data presented here were combined with ZEUS e{sup +}p neutral current data taken at {radical}(s)=300 GeV and the structure function F{sub 2}{sup em} was extracted. All results agree well with the predictions of the Standard Model.

  19. Heisenberg Model Analysis on Inelastic Powder Neutron Scattering Data Using Pure and K doped BaMn2 As2 samples

    NASA Astrophysics Data System (ADS)

    Ramazanoglu, Mehmet; Sapkota, A.; Pandey, A.; Johnston, D.; Goldman, Alan; Kreyssig, A.; Abernathy, D.; Niedziela, J.; Stone, M.; McQueeney, R. J.

    Low temperature powder inelastic neutron scattering measurements (INS) were performed on powders of Ba(1-x)KxMn2As2 with x=0(BMA),0.125 and 0.25. BMA is a G type antiferromagnet (AFM) which has local magnetic modulations bridging between the pnictide and cuprate superconductors. Hole doping (K) introduces more metallic behavior. The magnetic contribution to the intensities were retrieved by subtracting the estimated phonon background obtained at high momentum transfers from the raw. The resultant estimated magnetic intensities were analyzed by using damped harmonic oscillator model. The K doping effects create a broadening in the magnetic peak profiles consistent with expected weak FM fluctuations. We also analyzed the INS data using a powder integration routine which is based on J1-J2-Jz Heisenberg Model. The Monte Carlo integration technique is used to obtain the powder-averaged S(Q,E) for a series of Js. The representative values (with lowest chi-squared) obtained for BMA are in agreement with previous results. The values obtained for K doped samples were found in the close proximity to the parent ones. Overall we conclude that the original AFM structure seen in BMA retained its character even in the K doped samples with minimal differences. Work at Ames Laboratory is supported by USDOE under Contract No. DE-AC02-07CH11358 and Work at ITU is supported by TUBITAK 2232.

  20. X-ray edge singularity in resonant inelastic x-ray scattering (RIXS)

    NASA Astrophysics Data System (ADS)

    Markiewicz, Robert; Rehr, John; Bansil, Arun

    2013-03-01

    We develop a lattice model based on the theory of Mahan, Noziéres, and de Dominicis for x-ray absorption to explore the effect of the core hole on the RIXS cross section. The dominant part of the spectrum can be described in terms of the dynamic structure function S (q , ω) dressed by matrix element effects, but there is also a weak background associated with multi-electron-hole pair excitations. The model reproduces the decomposition of the RIXS spectrum into well- and poorly-screened components. An edge singularity arises at the threshold of both components. Fairly large lattice sizes are required to describe the continuum limit. Supported by DOE Grant DE-FG02-07ER46352 and facilitated by the DOE CMCSN, under grant number DE-SC0007091.

  1. Study of rlastic and inelastic {sup 11}B +α scattering and search for cluster states of enlarged radius in {sup 11}B

    SciTech Connect

    Danilov, A. N. Demyanova, A. S.; Dmitriev, S. V.; Ogloblin, A. A.; Belyaeva, T. L.; Goncharov, S. A.; Gurov, Yu. B.; Maslov, V. A.; Sobolev, Yu. G.; Trzaska, W.; Khlebnikov, S. V.; Heikkinen, P.; Julin, R.; Tyurin, G. P.; Burtebaev, N.; Zholdybayev, T.

    2015-09-15

    The differential cross sections for elastic and inelastic {sup 11}B + α scattering were measured at the alpha-particle energy of 65 MeV, the inelastic-scattering processes leading to the excitation of known states of {sup 11}B up to excitation energies of about 14 MeV. Data on elastic scattering were analyzed together with those that were published earlier for lower energies. The cross sections for inelastic scattering were analyzed on the basis of the distorted-wave method. A modified diffractionmodel was used to determine the root-mean-square radii of excited states. The radii of states whose excitation energies were below about 7MeV were found to agree with radius of the ground state to within 0.1 to 0.15 fm. This result complieswith the traditional idea that the low-lying states of {sup 11}B have a shell structure. The possibility that these states belong to the predicted rotational bands, which, if any, are truncated to three states, cannot be ruled out either. The majority of the observed highly excited states are distributed among four rotational bands. The moments of inertia of these bands are close; for the band based on the 3/2{sup −} state at E* = 8.56 MeV, they are even higher than those of the Hoyle state in the {sup 12}C nucleus. The measured radii of states associated with these bands of {sup 11}B are larger than the ground-state radius by 0.7 to 1.0 fm and are also close to the radius of the Hoyle state. The results of the present study agree with the existing predictions that the cluster structure of the {sup 11}B nucleus is diverse at high excitation energies. The hypothesis that the {sup 11}B nucleus features a “giant” state of size commensurate with those in heavy nuclei was not confirmed.

  2. Determination of the effective inelastic p anti-p cross-section for the D0 Run II luminosity measurement

    SciTech Connect

    Edwards, T.; Yacoob, S.; Andeen, T.; Begel, M.; Casey, B.C.K.; Partridge, R.; Schellman, H.; Sznajder, A.; /Rio de Janeiro State U.

    2004-11-01

    The authors determine the effective inelastic p{bar p} cross-section into the D0 Luminosity Monitor for all run periods prior to September 2004. This number is used to relate the measured inelastic collision rate to the delivered luminosity. The key ingredients are the inelastic p{bar p} cross-section, the Luminosity Monitor efficiency, and the modeling of kinematic distributions for various inelastic processes used to determine the detector acceptance. The resulting value is {sigma}{sub p{bar p},eff} = 46 {+-} 3 mb.

  3. Modeling non-harmonic behavior of materials from experimental inelastic neutron scattering and thermal expansion measurements

    DOE PAGESBeta

    Bansal, Dipanshu; Aref, Amjad; Dargush, Gary; Delaire, Olivier A.

    2016-07-20

    Based on thermodynamic principles, we derive expressions quantifying the non-harmonic vibrational behavior of materials, which are rigorous yet easily evaluated from experimentally available data for the thermal expansion coefficient and the phonon density of states. These experimentally-derived quantities are valuable to benchmark first-principles theoretical predictions of harmonic and non-harmonic thermal behaviors using perturbation theory, ab initio molecular-dynamics, or Monte-Carlo simulations. In this study, we illustrate this analysis by computing the harmonic, dilational, and anharmonic contributions to the entropy, internal energy, and free energy of elemental aluminum and the ordered compound FeSi over a wide range of temperature. Our results agreemore » well with previous data in the literature and provide an efficient approach to estimate anharmonic effects in materials.« less

  4. Inelastic scattering research at a 1 MW long pulse spallation neutron source

    SciTech Connect

    Carlile, C.J.

    1995-12-31

    The brief was, with respect to the LPSS bench mark design supplied (60 Hz, 1 MW, Imsec proton pulse, with a split, non-fissile target and 4 moderators in a flux trap geometry design), to identify a set of instruments, and to assess their performance with respect to existing spectrometers on other sources. Any modifications to the existing instruments which would make them more effective on the bench-mark source, or conversely, any modifications to the source bench-mark required by the proposed instruments were to be identified, as were any uncertainties in the estimated performances, or any R & D needed to make the proposed instruments viable. Any new instrument concepts specifically matched to the long pulse itself were to be identified and assessed. This process was to result in an indicative list of instruments for the source. A figure of around 10 spectrometers was to be aimed for.

  5. Modeling non-harmonic behavior of materials from experimental inelastic neutron scattering and thermal expansion measurements

    NASA Astrophysics Data System (ADS)

    Bansal, Dipanshu; Aref, Amjad; Dargush, Gary; Delaire, Olivier

    2016-09-01

    Based on thermodynamic principles, we derive expressions quantifying the non-harmonic vibrational behavior of materials, which are rigorous yet easily evaluated from experimentally available data for the thermal expansion coefficient and the phonon density of states. These experimentally-derived quantities are valuable to benchmark first-principles theoretical predictions of harmonic and non-harmonic thermal behaviors using perturbation theory, ab initio molecular-dynamics, or Monte-Carlo simulations. We illustrate this analysis by computing the harmonic, dilational, and anharmonic contributions to the entropy, internal energy, and free energy of elemental aluminum and the ordered compound \\text{FeSi} over a wide range of temperature. Results agree well with previous data in the literature and provide an efficient approach to estimate anharmonic effects in materials.

  6. Synergy of inelastic and elastic energy loss. Temperature effects and electronic stopping power dependence

    SciTech Connect

    Zarkadoula, Eva; Xue, Haizhou; Zhang, Yanwen; Weber, William J.

    2015-06-16

    A combination of an inelastic thermal spike model suitable for insulators and molecular dynamics simulations is used to study the effects of temperature and electronic energy loss on ion track formation, size and morphology in SrTiO3 systems with pre-existing disorder. We find temperature dependence of the ion track size. In addition, we find a threshold in the electronic energy loss for a given pre-existing defect concentration, which indicates a threshold in the synergy between the inelastic and elastic energy loss.

  7. Synergy of inelastic and elastic energy loss. Temperature effects and electronic stopping power dependence

    DOE PAGESBeta

    Zarkadoula, Eva; Xue, Haizhou; Zhang, Yanwen; Weber, William J.

    2015-06-16

    A combination of an inelastic thermal spike model suitable for insulators and molecular dynamics simulations is used to study the effects of temperature and electronic energy loss on ion track formation, size and morphology in SrTiO3 systems with pre-existing disorder. We find temperature dependence of the ion track size. In addition, we find a threshold in the electronic energy loss for a given pre-existing defect concentration, which indicates a threshold in the synergy between the inelastic and elastic energy loss.

  8. Computation of the ultraviolet absorption and electron inelastic scattering cross section of multishell fullerenes

    NASA Astrophysics Data System (ADS)

    Lucas, A. A.; Henrard, L.; Lambin, Ph.

    1994-01-01

    We develop a model in which the ultraviolet dielectric tensor of planar graphite is transported to the spherical geometry of a nanoscale multishell fullerene with a central cavity. This is accomplished by assigning to every point of the multishell fullerene a local dielectric tensor identical to that of graphite with its c axis aligned along the local radial direction. The dynamic, multipolar polarizabilities of the model fullerene are obtained from the exact solutions of the nonretarded Maxwell equations. The ultraviolet absorption spectrum of the hollow fullerene is calculated as a function of the ratio of the inner and outer radii. Comparisons of the theoretical absorption spectra with the 2175-Å interstellar extinction hump and with recent absorption measurements for synthetic multishell fullerenes indicate that the dielectric properties of graphite are qualitatively adequate for understanding the optical data. However, difficulties persist with both the astrophysical and laboratory absorption peaks which lead us to consider the possible role of multishell fullerene aggregation into small or large clusters. It is found that the effect of clustering is important and reduces but does not remove completely the quantitative difficulties of the graphitic multishell model. Finally theoretical electron-energy-loss spectra (EELS) of these structures with an empty or filled cavity are calculated from the multipolar polarizabilities of the model. The results indicate that spatially resolved EELS measurements should be ideally suited to study the dielectric properties of individual multishell fullerenes and to ascertain to what extent they differ from those of planar graphite.

  9. Inelastic electron scattering investigation of the Sb/GaAs(110) system

    SciTech Connect

    Annovi, G.; Betti, M.G.; del Pennino, U.; Mariani, C. )

    1990-06-15

    A high-resolution electron-energy-loss spectroscopy study of the Sb/({ital n}-type GaAs (110)) system grown at room temperature is presented. A very wide range of antimony coverages was exploited (from 0.02 to 200 monolayers). The amorphous-polycrystalline transition accompanied by the semiconductor-metal transition, taking place in the deposited overlayer, was brought into evidence through the analysis of the energy-loss structures related to the electronic and the vibrational excitations of the system in different energy-loss regions. In particular, the intensity change and the energy shift undergone by the substrate's Fuchs-Kliewer optical phonon, and the intensity modification of the dopant-induced free-carrier plasmon, marked a critical value for 15 monolayers coverage. The band-bending change upon antimony chemisorption has also been estimated from the plasmon-energy position, and an origin for the states inducing the Fermi-level pinning has been suggested. The evolution as a function of coverage of an electronic excitation proper of Sb, which shifts from 90 to 125 meV of loss energy, has been explained as being due to a size effect'' due to the varying overlayer thickness. This result has been obtained through the comparison of the experimental loss function with a model one. Moreover, the dielectric function of antimony has been determined in the 0.045--0.5-eV energy range. The high-resolution electron-energy-loss technique is also presented as a superb probe for the study of the electronic structure of narrow-band-gap surface and interface systems.

  10. New opportunities for quasielastic and inelastic neutron scattering at steady-state sources using mechanical selection of the incident and final neutron energy

    DOE PAGESBeta

    Mamantov, Eugene

    2015-06-12

    We propose a modification of the neutron wide-angle velocity selector (WAVES) device that enables inelastic (in particular, quasielastic) scattering measurements not relying on the neutron time-of-flight. The proposed device is highly suitable for a steady-state neutron source, somewhat similar to a triple-axis spectrometer, but with simultaneous selection of the incident and final neutron energy over a broad range of scattering momentum transfer. Both the incident and final neutron velocities are defined by the WAVES geometry and rotation frequency. The variable energy transfer is achieved through the natural variation of the velocity of the transmitted neutrons as a function of themore » scattering angle component out of the equatorial plane.« less

  11. New opportunities for quasielastic and inelastic neutron scattering at steady-state sources using mechanical selection of the incident and final neutron energy

    SciTech Connect

    Mamantov, Eugene

    2015-06-12

    We propose a modification of the neutron wide-angle velocity selector (WAVES) device that enables inelastic (in particular, quasielastic) scattering measurements not relying on the neutron time-of-flight. The proposed device is highly suitable for a steady-state neutron source, somewhat similar to a triple-axis spectrometer, but with simultaneous selection of the incident and final neutron energy over a broad range of scattering momentum transfer. Both the incident and final neutron velocities are defined by the WAVES geometry and rotation frequency. The variable energy transfer is achieved through the natural variation of the velocity of the transmitted neutrons as a function of the scattering angle component out of the equatorial plane.

  12. Measurement of single and double spin asymmetries in semi-inclusive deep-inelastic scattering on proton and deuteron

    NASA Astrophysics Data System (ADS)

    Koirala, Suman Bandhu

    The EG1-DVCS experiment with CLAS at Jefferson Lab collected semi-inclusive pion electro-production data on longitudinally polarized solid state NH3 and ND3 targets with longitudinally polarized electrons of approximately 6 GeV energy. Data on all three pion channels, pi +, pi-- and pi0, were collected simultaneously. The charged pions were identified by their time-of-flight information whereas the neutral pions were reconstructed from the invariant mass of two photons. The experiment covered a wide kinematic range: 1 GeV 2 ≤ Q2 ≤ 3.2 GeV2, 0.12 ≤ xB ≤ 0.48, 0.0 GeV ≤ Ph⊥ ≤ 1.0 GeV and 0.3 ≤ z ≤ 0.7. The beam single (ALU), target single (AUL) and beam-target double ( ALL) spin azimuthal asymmetries in semi-inclusive deep-inelastic scattering (SIDIS) off the proton and the deuteron extracted from the data are presented. The results of the azimuthal asymmetries for the proton are presented as a function of two variables: (xB, Ph⊥), (z, P h⊥) and (xB, z). Due to limited statistics, the azimuthal asymmetries for the deuteron are presented as a function of a single variable for the variables xB, z and Ph ⊥. Some theoretical and phenomenological predictions as well as earlier published results are compared with the results from this analysis. All the results are plotted and suitably tabulated for further analysis. The SIDIS azimuthal asymmetries are convolutions of fragmentation functions and transverse momentum dependent parton distribution functions (TMDs). The TMDs describe transverse momenta and spins of quarks and gluons inside nucleons. They open a window on the contribution of the orbital angular momentum of the quarks and gluons to the total spin of the nucleons. The results presented in this work are sensitive to these leading twist TMDs: f 1, g1, h⊥ 1L, and h⊥ 1. The significant precision of the results from this analysis will highly constrain the extractions of the associated TMDs which will substantially contribute towards further

  13. Carbonate-Bridged Lanthanoid Triangles: Single-Molecule Magnet Behavior, Inelastic Neutron Scattering, and Ab Initio Studies.

    PubMed

    Giansiracusa, Marcus J; Vonci, Michele; Van den Heuvel, Willem; Gable, Robert W; Moubaraki, Boujemaa; Murray, Keith S; Yu, Dehong; Mole, Richard A; Soncini, Alessandro; Boskovic, Colette

    2016-06-01

    Optimization of literature synthetic procedures has afforded, in moderate yield, homogeneous and crystalline samples of the five analogues Na11[{RE(OH2)}3CO3(PW9O34)2] (1-RE; RE = Y, Tb, Dy, Ho, and Er). Phase-transfer methods have allowed isolation of the mixed salts (Et4N)9Na2[{RE(OH2)}3CO3(PW9O34)2] (2-RE; RE = Y and Er). The isostructural polyanions in these compounds are comprised of a triangular arrangement of trivalent rare-earth ions bridged by a μ3-carbonate ligand and sandwiched between two trilacunary Keggin {PW9O34} polyoxometalate ligands. Alternating-current (ac) magnetic susceptibility studies of 1-Dy, 1-Er, and 2-Er reveal the onset of frequency dependence for the out-of-phase susceptibility in the presence of an applied magnetic field at the lowest measured temperatures. Inelastic neutron scattering (INS) spectra of 1-Ho and 1-Er exhibit transitions between the lowest-lying crystal-field (CF) split states of the respective J = 8 and (15)/2 ground-state spin-orbit multiplets of the Ho(III) and Er(III) ions. Complementary ab initio calculations performed for these two analogues allow excellent reproduction of the experimental magnetic susceptibility and low-temperature magnetization data and are in reasonable agreement with the experimental INS data. The ab initio calculations reveal that the slight difference in coordination environments of the three Ln(III) ions in each complex gives rise to differences in the CF splitting that are not insignificant. This theoretical result is consistent with the observation of multiple relaxation processes by ac magnetic susceptibility and the broadness of the measured INS peaks. The ab initio calculations also indicate substantial mixing of the MJ contributions to the CF split energy levels of each Ln(III) ion. Calculations indicate that the CF ground states of the Ho(III) centers in 1-Ho are predominantly comprised of contributions from small MJ, while those of the Er(III) centers in 1-Er are predominantly

  14. Metal-ligand Covalency of Iron Complexes from High-Resolution Resonant Inelastic X-ray Scattering

    PubMed Central

    Lundberg, Marcus; Kroll, Thomas; DeBeer, Serena; Bergmann, Uwe; Wilson, Samuel A.; Glatzel, Pieter; Nordlund, Dennis; Hedman, Britt; Hodgson, Keith O.; Solomon, Edward I.

    2013-01-01

    Data from Kα resonant inelastic X-ray scattering (RIXS) have been used to extract electronic structure information, i.e., the covalency of metal-ligand bonds, for four iron complexes using an experimentally based theoretical model. Kα RIXS involves resonant 1s → 3d excitation and detection of the 2p → 1s (Kα) emission. This two-photon process reaches similar final states as single-photon L-edge (2p → 3d) X-ray absorption spectroscopy (XAS), but involves only hard X-rays and can therefore be used to get high-resolution L-edge-like spectra for metal proteins, solution catalysts and their intermediates. To analyze the information content of Kα RIXS spectra, data have been collected for four characteristic σ-donor and π-backdonation complexes; ferrous tacn [FeII(tacn)2]Br2, ferrocyanide [FeII(CN)6]K4, ferric tacn [FeIII(tacn)2]Br3 and ferricyanide [FeIII(CN)6]K3. From these spectra metal-ligand covalencies can be extracted using a charge-transfer multiplet model, without previous information from the L-edge XAS experiment. A direct comparison of L-edge XAS and Kα RIXS spectra show that the latter reaches additional final states, e.g., when exciting into the eg (σ*) orbitals, and the splitting between final states of different symmetry provides an extra dimension that makes Kα RIXS a more sensitive probe of σ-bonding. Another key difference between L-edge XAS and Kα RIXS is the π-backbonding features in ferro- and ferricyanide that are significantly more intense in L-edge XAS compared to Kα RIXS. This shows that two methods are complimentary in assigning electronic structure. The Kα RIXS approach can thus be used as a stand-alone method, in combination with L-edge XAS for strongly covalent systems that are difficult to probe by UV/Vis spectroscopy, or as an extension to conventional absorption spectroscopy for a wide range of transition metal enzymes and catalysts. PMID:24131028

  15. Confirming a predicted selection rule in inelastic neutron scattering spectroscopy: the quantum translator-rotator H2 entrapped inside C60.

    PubMed

    Xu, Minzhong; Jiménez-Ruiz, Mónica; Johnson, Mark R; Rols, Stéphane; Ye, Shufeng; Carravetta, Marina; Denning, Mark S; Lei, Xuegong; Bačić, Zlatko; Horsewill, Anthony J

    2014-09-19

    We report an inelastic neutron scattering (INS) study of a H2 molecule encapsulated inside the fullerene C60 which confirms the recently predicted selection rule, the first to be established for the INS spectroscopy of aperiodic, discrete molecular compounds. Several transitions from the ground state of para-H2 to certain excited translation-rotation states, forbidden according to the selection rule, are systematically absent from the INS spectra, thus validating the selection rule with a high degree of confidence. Its confirmation sets a precedent, as it runs counter to the widely held view that the INS spectroscopy of molecular compounds is not subject to any selection rules. PMID:25279623

  16. The GALAXIES beamline at the SOLEIL synchrotron: inelastic X-ray scattering and photoelectron spectroscopy in the hard X-ray range.

    PubMed

    Rueff, J P; Ablett, J M; Céolin, D; Prieur, D; Moreno, Th; Balédent, V; Lassalle-Kaiser, B; Rault, J E; Simon, M; Shukla, A

    2015-01-01

    The GALAXIES beamline at the SOLEIL synchrotron is dedicated to inelastic X-ray scattering (IXS) and photoelectron spectroscopy (HAXPES) in the 2.3-12 keV hard X-ray range. These two techniques offer powerful complementary methods of characterization of materials with bulk sensitivity, chemical and orbital selectivity, resonant enhancement and high resolving power. After a description of the beamline components and endstations, the beamline capabilities are demonstrated through a selection of recent works both in the solid and gas phases and using either IXS or HAXPES approaches. Prospects for studies on liquids are discussed.

  17. Influence of magnetism on phonons in CaFe{sub 2}As{sub 2} as seen via inelastic x-ray scattering.

    SciTech Connect

    Hahn, S. E.; Lee, Y.; Ni, N.; Canfield, P. C.; Goldman, A. I.; McQueeney, R. J.; Harmon, B. N.; Alatas, A.; Leu, B. M.; Alp, E. E.; Chung, D. Y.; Todorov, I. S.; Kanatzidis, M. G.; Iowa State Univ.; Northwestern Univ.

    2009-01-01

    In the iron pnictides, the strong sensitivity of the iron magnetic moment to the arsenic position suggests a significant relationship between phonons and magnetism. We measured the phonon dispersion of several branches in the high-temperature tetragonal phase of CaFe{sub 2}As{sub 2} using inelastic x-ray scattering on single-crystal samples. These measurements were compared to ab initio calculations of the phonons. Spin-polarized calculations imposing the antiferromagnetic order present in the low-temperature orthorhombic phase dramatically improve agreement between theory and experiment. This is discussed in terms of the strong antiferromagnetic correlations that are known to persist in the tetragonal phase.

  18. Electronic Structure in Thin Film Organic Semiconductors Studied using Soft X-ray Emission and Resonant Inelastic X-ray Scattering

    SciTech Connect

    Zhang,Y.; Downes, J.; Wang, S.; Learmonth, T.; Plucinski, L.; Matsuura, A.; McGuinness, C.; Glans, P.; Bernardis, S.; et al.

    2006-01-01

    The electronic structure of thin films of the organic semiconductors copper and vanadyl (VO) phthalocyanine (Pc) has been measured using resonant soft X-ray emission spectroscopy and resonant inelastic X-ray scattering. For Cu-Pc we report the observation of two discrete states near E{sub F}. This differs from published photoemission results, but is in excellent agreement with density functional calculations. For VO-Pc, the vanadyl species is shown to be highly localized. Both dipole forbidden V 3d to V 3d*, and O 2p to V 3d* charge transfer transitions are observed, and explained in a local molecular orbital model.

  19. Snapshots of the fluctuating hydrogen bond network in liquid water on the sub-femtosecond timescale with vibrational resonant inelastic x-ray scattering.

    PubMed

    Pietzsch, A; Hennies, F; Miedema, P S; Kennedy, B; Schlappa, J; Schmitt, T; Strocov, V N; Föhlisch, A

    2015-02-27

    Liquid water molecules interact strongly with each other, forming a fluctuating hydrogen bond network and thereby giving rise to the anomalous phase diagram of liquid water. Consequently, symmetric and asymmetric water molecules have been found in the picosecond time average with IR and optical Raman spectroscopy. With subnatural linewidth resonant inelastic x-ray scattering (RIXS) at vibrational resolution, we take sub-femtosecond snapshots of the electronic and structural properties of water molecules in the hydrogen bond network. We derive a strong dominance of nonsymmetric molecules in liquid water in contrast to the gas phase on the sub-femtosecond timescale of RIXS and determine the fraction of highly asymmetrically distorted molecules.

  20. The GALAXIES beamline at the SOLEIL synchrotron: inelastic X-ray scattering and photoelectron spectroscopy in the hard X-ray range.

    PubMed

    Rueff, J P; Ablett, J M; Céolin, D; Prieur, D; Moreno, Th; Balédent, V; Lassalle-Kaiser, B; Rault, J E; Simon, M; Shukla, A

    2015-01-01

    The GALAXIES beamline at the SOLEIL synchrotron is dedicated to inelastic X-ray scattering (IXS) and photoelectron spectroscopy (HAXPES) in the 2.3-12 keV hard X-ray range. These two techniques offer powerful complementary methods of characterization of materials with bulk sensitivity, chemical and orbital selectivity, resonant enhancement and high resolving power. After a description of the beamline components and endstations, the beamline capabilities are demonstrated through a selection of recent works both in the solid and gas phases and using either IXS or HAXPES approaches. Prospects for studies on liquids are discussed. PMID:25537606