Coulomb Sturmians as a basis for molecular calculations
DEFF Research Database (Denmark)
Avery, John Scales; Avery, James Emil
2012-01-01
mathematical difficulty of evaluating interelectron repulsion integrals when exponential-type orbitals (ETOs) are used. In this paper we show that when many-centre Coulomb Sturmian ETOs are used as a basis, the most important integrals can be evaluated rapidly and accurately by means of the theory...
Przybytek, Michal; Helgaker, Trygve
2013-08-07
We analyze the accuracy of the Coulomb energy calculated using the Gaussian-and-finite-element-Coulomb (GFC) method. In this approach, the electrostatic potential associated with the molecular electronic density is obtained by solving the Poisson equation and then used to calculate matrix elements of the Coulomb operator. The molecular electrostatic potential is expanded in a mixed Gaussian-finite-element (GF) basis set consisting of Gaussian functions of s symmetry centered on the nuclei (with exponents obtained from a full optimization of the atomic potentials generated by the atomic densities from symmetry-averaged restricted open-shell Hartree-Fock theory) and shape functions defined on uniform finite elements. The quality of the GF basis is controlled by means of a small set of parameters; for a given width of the finite elements d, the highest accuracy is achieved at smallest computational cost when tricubic (n = 3) elements are used in combination with two (γ(H) = 2) and eight (γ(1st) = 8) Gaussians on hydrogen and first-row atoms, respectively, with exponents greater than a given threshold (αmin (G)=0.5). The error in the calculated Coulomb energy divided by the number of atoms in the system depends on the system type but is independent of the system size or the orbital basis set, vanishing approximately like d(4) with decreasing d. If the boundary conditions for the Poisson equation are calculated in an approximate way, the GFC method may lose its variational character when the finite elements are too small; with larger elements, it is less sensitive to inaccuracies in the boundary values. As it is possible to obtain accurate boundary conditions in linear time, the overall scaling of the GFC method for large systems is governed by another computational step-namely, the generation of the three-center overlap integrals with three Gaussian orbitals. The most unfavorable (nearly quadratic) scaling is observed for compact, truly three-dimensional systems
Directory of Open Access Journals (Sweden)
Yannis Tanoudis
2011-06-01
Full Text Available In the three-dimensional flat space, a classical Hamiltonian, which has five functionally independent integrals of motion, including the Hamiltonian, is characterized as superintegrable. Kalnins, Kress and Miller (J. Math. Phys. 48 (2007, 113518, 26 pages have proved that, in the case of nondegenerate potentials, i.e. potentials depending linearly on four parameters, with quadratic symmetries, posses a sixth quadratic integral, which is linearly independent of the other integrals. The existence of this sixth integral imply that the integrals of motion form a ternary quadratic Poisson algebra with five generators. The superintegrability of the generalized Kepler-Coulomb potential that was investigated by Verrier and Evans (J. Math. Phys. 49 (2008, 022902, 8 pages is a special case of superintegrable system, having two independent integrals of motion of fourth order among the remaining quadratic ones. The corresponding Poisson algebra of integrals is a quadratic one, having the same special form, characteristic to the nondegenerate case of systems with quadratic integrals. In this paper, the ternary quadratic associative algebra corresponding to the quantum Verrier-Evans system is discussed. The subalgebras structure, the Casimir operators and the the finite-dimensional representation of this algebra are studied and the energy eigenvalues of the nondegenerate Kepler-Coulomb are calculated.
Can Coulomb Sturmians Be Used as a Basis for N-Electron Molecular Calculations?
DEFF Research Database (Denmark)
Avery, John Scales; Avery, James Emil
2009-01-01
A method is proposed for using isoenergetic configurations formed from many-center Coulomb Sturmians as a basis for calculations on N-electron molecules. Such configurations are solutions to an approximate N-electron Schrödinger equation with a weighted potential, and they are thus closely...... analogous to the Goscinskian configurations that we have used previously to study atomic spectra. We show that when the method is applied to diatomic molecules, all of the relevant integrals are pure functions of the parameter s=kR, and therefore they can be evaluated once and for all and stored....
Effect of exact Coulomb-exchange calculations on band-head spectra of odd-proton nuclei
Directory of Open Access Journals (Sweden)
Koh Meng-Hock
2017-01-01
Full Text Available Previous calculations of band-head energy spectra of odd-mass heavy nuclei in the Hartree-Fock-plus-Bardeen-Cooper-Schrieffer (HF-BCS framework showed that the agreement with data is better for odd-neutron as compared to odd-proton nuclei. The reason for a poorer agreement with data for the latter have been ascribed to the possible usage of the Slater approximation in calculating the Coulomb-exchange term. In this work, we report the effect of exact Coulomb-exchange calculations on band-head energy spectra of two odd-proton nuclei (namely 237Np and 241Am as compared to the results obtained using the Slater approximation. We performed self-consistent blocking calculations while taking the breaking of time-reversal symmetry at the mean-field level into account due to the unpaired nucleon. The SkM* and SIII parametrizations of the Skyrme interaction have been employed to approximate the effective nucleon-nucleon interaction while a seniority force is used for the pairing channel. Contrary to what was expected, our preliminary results show no improvement on the band-head spectra as compared to data when the Coulomb-exchange term is calculated exactly.
Energy Technology Data Exchange (ETDEWEB)
Dimits, A M; Wang, C; Caflisch, R; Cohen, B I; Huang, Y
2008-08-06
We investigate the accuracy of and assumptions underlying the numerical binary Monte-Carlo collision operator due to Nanbu [K. Nanbu, Phys. Rev. E 55 (1997)]. The numerical experiments that resulted in the parameterization of the collision kernel used in Nanbu's operator are argued to be an approximate realization of the Coulomb-Lorentz pitch-angle scattering process, for which an analytical solution for the collision kernel is available. It is demonstrated empirically that Nanbu's collision operator quite accurately recovers the effects of Coulomb-Lorentz pitch-angle collisions, or processes that approximate these (such interspecies Coulomb collisions with very small mass ratio) even for very large values of the collisional time step. An investigation of the analytical solution shows that Nanbu's parameterized kernel is highly accurate for small values of the normalized collision time step, but loses some of its accuracy for larger values of the time step. Careful numerical and analytical investigations are presented, which show that the time dependence of the relaxation of a temperature anisotropy by Coulomb-Lorentz collisions has a richer structure than previously thought, and is not accurately represented by an exponential decay with a single decay rate. Finally, a practical collision algorithm is proposed that for small-mass-ratio interspecies Coulomb collisions improves on the accuracy of Nanbu's algorithm.
Calculation Of The Nanbu-Trubnikov Kernel: Implications For Numerical Modeling Of Coulomb Collisions
Energy Technology Data Exchange (ETDEWEB)
Dimits, A; Cohen, B I; Wang, C; Caflisch, R; Huang, Y
2009-07-02
We investigate the accuracy of and assumptions underlying the numerical binary Monte-Carlo collision operator due to Nanbu [K. Nanbu, Phys. Rev. E 55 (1997)]. The numerical experiments that resulted in Nanbu's parameterized collision kernel are approximate realizations of the Coulomb-Lorentz pitch-angle scattering process, for which an analytical solution is available. It is demonstrated empirically that Nanbu's collision operator quite accurately recovers the effects of Coulomb-Lorentz pitch-angle collisions, or processes that approximate these even for very large values of the collisional time step. An investigation of the analytical solution shows that Nanbu's parameterized kernel is highly accurate for small values of the normalized collision time step, but loses some of its accuracy for larger values of the time step. Finally, a practical collision algorithm is proposed that for small-mass-ratio Coulomb collisions improves on the accuracy of Nanbu's algorithm.
An algorithm for the calculation of the partial wave expansion of the Coulomb-distorted plane wave
Hornyak, I.; Kruppa, A. T.
2015-12-01
The partial wave expansion of the Coulomb-distorted plane wave is determined by the help of the complex generalized hypergeometric function 2F2(a , a ; a + l + 1 , a - l ; z) . An algorithm for the calculation of 2F2(a , a ; a + l + 1 , a - l ; z) is created and it is implemented as a FORTRAN-90 code. The code is fast and its accuracy is 14 significant decimal digits.
Energy Technology Data Exchange (ETDEWEB)
Djouder, M., E-mail: djouder-madjid@ummto.dz; Kermoun, F.; Mitiche, M. D.; Lamrous, O. [Laboratoire de Physique et Chimie Quantique, Université Mouloud Mammeri Tizi-Ouzou, BP 17 RP, 15000 Tizi-Ouzou (Algeria)
2016-01-15
Dust particles observed in universe as well as in laboratory and technological plasma devices are still under investigation. At low temperature, these particles are strongly negatively charged and are able to form a 2D or 3D coulomb crystal. In this work, our aim was to check the ideal gas law validity for a 2D single-layer dust crystal recently reported in the literature. For this purpose, we have simulated, using the molecular dynamics method, its thermodynamic properties for different values of dust particles number and confinement parameters. The obtained results have allowed us to invalidate the ideal gas behaviour and to propose an effective equation of state which assumes a near zero dust temperature. Furthermore, the value of the calculated sound velocity was found to be in a good agreement with experimental data published elsewhere.
An, W. F.; Lu, C. W.; Sun, S. Y.; Jia, X. F.
2015-08-01
The four-body modified Coulomb-Born approximation including the internuclear interaction (MCB-NN) with a full quantum-mechanical method, is applied to investigate single ionization of helium by 2 MeV/amu C6+ impact. The fully differential cross-sections (FDCS) are calculated for a variety of momentum transfers and ejected electron energies in the scattering plane. The obtained results are compared with the experimental data and the three-body distorted wave-eikonal initial state (3DW-EIS) results and we find that the magnitudes and the angular distribution of the FDCS is well reproduced by the MCB-NN theory for low ejected electron energy. Especially in the recoil region, the present MCB-NN results yield an excellent agreement with experiment.
Harb, Moussab
2013-12-05
We report a systematic study on the optoelectronic properties of Se-modified anatase TiO2 investigated by DFT (including the perturbation theory approach DFPT) within the screened coulomb hybrid HSE06 formalism to guarantee accurate band gap and electronic excitation predictions. Various selenium species at substitutional sites for O or Ti, at interstitial sites, as well as at mixed substitutional/interstitial sites are studied. Among the explored structures, Ti(1-2x)O2Se2x (containing Se4+ species), TiO(2-x)Sex (containing Se2- species), and TiO(2-x)Se2x (containing Se2 2- species) reveal significant enhanced visible-light optical absorption spectra with new absorption features appearing at 500, 600, and 690 nm, respectively. Our calculated spectra are found to be in good agreement with those obtained in available experimental works. The band gap narrowing in these materials originates from incorporation of newly occupied electronic levels within 0.5-1.5 eV above the original valence band of TiO 2, leading to new narrowed band gaps of 2.5, 2.0, and 1.8 eV respectively. Our calculations also reveal suitable band positions of Ti (1-2x)O2Se2x and TiO(2-x)Se x for overall water splitting, whereas TiO(2-x)Se 2x shows an unsuitable valence band position for the oxygen evolution reaction. In contrast, the localized electronic character of the new occupied states on the Se 4p orbitals and only on the O 2p orbitals linked to the Se species makes the holes mobility limited in this material and the recombination rate of charge carriers greatly increased in the bulk. © 2013 American Chemical Society.
Coulombic Transformation in Momentum Space
Yamaguchi, M.; Kamada, H.; Glöckle, W.
2013-08-01
We studied the Coulombic transformation of potential in momentum space. The Coulombic transformation is defined as a unitary transformation in momentum space, which is equivalent of the Coulomb-Fourier transformation in coordinate space. The analytic continuation scheme avoids the difficulty which is occurred from the singularity of the Coulomb wave function in momentum space. We adopted the point method to perform the analytic continuation. The validity of the new scheme is checked by comparing with the analytic solution for the Malfliet-Tjon potential. Numerical calculation of the integration was done by separating into four intervals. We demonstrate the high accuracy of our calculation.
Derrickson, J. H.; Dake, S.; Dong, B. L.; Eby, P. B.; Fountain, W. F.; Fuki, M.; Gregory, J. C.; Hayashi, T.; Iyono, A.; King, D. T.
1989-01-01
Recently, new calculations were made of the direct Coulomb pair cross section that rely less in arbitrary parameters. More accurate calculations of the cross section down to low pair energies were made. New measurements of the total direct electron pair yield, and the energy and angular distribution of the electron pairs in emulsion were made for O-16 at 60 and 200 GeV/amu at S-32 at 200 GeV/amu which give satisfactory agreement with the new calculations. These calculations and measurements are presented along with previous accelerator measurements made of this effect during the last 40 years. The microscope scanning criteria used to identify the direct electron pairs is described. Prospects for application of the pair method to cosmic ray energy measurements in the region 10 (exp 13) to 10 (exp 15) eV/amu are discussed.
Cocco, M.; Hainzl, S.; Woessner, J.; Enescu, B.; Catalli, F.; Lombardi, A.
2009-12-01
It is nowadays well established that both Coulomb stress perturbations and the rate- and state-dependent frictional response of fault populations are needed to model the spatial and temporal evolution of seismicity. This represents the most popular physics-based approach to forecast the rate of earthquake production and its performances have to be verified with respect to alternative statistical methods. Despite the numerous applications of Coulomb stress interactions, a rigorous validation of the forecasting capabilities is still missing. In this work, we use the Dieterich (1994) physics-based approach to simulate the spatio-temporal evolution of seismicity caused by stress changes applied to an infinite population of nucleating patches modelled through a rate- and state-dependent friction law. According to this model, seismicity rate changes depend on the amplitude of stress perturbation, the physical constitutive properties of faults (represented by the parameter Aσ), the stressing rate and the background seismicity rate of the study area. In order to apply this model in a predictive manner, we need to understand the variability of input physical model parameters and their correlations. We first discuss the impact of uncertainties in model parameters and, in particular, in computed coseismic stress perturbations on the seismicity rate changes forecasted through the frictional model. We aim to understand how the variability of Coulomb stress changes affects the correlation between predicted and observed changes in the rate of earthquake production. We use the aftershock activity following the 1992 M 7.3 Landers (California) earthquake as one of our case studies. We analyze the variability of stress changes resulting from the use of different published slip distributions. We find that the standard deviation of the uncertainty is of the same size as the absolute stress change and that their ratio, the coefficient of variation (CV), is approximately constant in
Fay, Temple H.
2012-01-01
Viscous damping is commonly discussed in beginning differential equations and physics texts but dry friction or Coulomb friction is not despite dry friction being encountered in many physical applications. One reason for avoiding this topic is that the equations involve a jump discontinuity in the damping term. In this article, we adopt an energy…
Lipparini, Filippo; Kirsch, Till; Köhn, Andreas; Gauss, Jürgen
2017-07-11
We combine internally contracted multireference coupled cluster theory with a four-component treatment of scalar-relativistic effects based on the spin-free Dirac-Coulomb Hamiltonian. This strategy allows for a rigorous treatment of static and dynamic correlation as well as scalar-relativistic effects, which makes it viable to describe molecules containing heavy transition elements. The use of a spin-free formalism limits the impact of the four-component treatment on the computational cost to the non-rate-determining steps of the calculations. We apply the newly developed method to the lowest singlet and triplet states of the monoxides of titanium, zirconium, and hafnium and show how the interplay between electronic correlation and relativistic effects explains the electronic structure of such molecules.
Cheng, Lan; Stopkowicz, Stella; Gauss, Jürgen
2013-12-07
A perturbative approach to compute second-order spin-orbit (SO) corrections to a spin-free Dirac-Coulomb Hartree-Fock (SFDC-HF) calculation is suggested. The proposed scheme treats the difference between the DC and SFDC Hamiltonian as perturbation and exploits analytic second-derivative techniques. In addition, a cost-effective scheme for incorporating relativistic effects in high-accuracy calculations is suggested consisting of a SFDC coupled-cluster treatment augmented by perturbative SO corrections obtained at the HF level. Benchmark calculations for the hydrogen halides HX, X = F-At as well as the coinage-metal fluorides CuF, AgF, and AuF demonstrate the accuracy of the proposed perturbative treatment of SO effects on energies and electrical properties in comparison with the more rigorous full DC treatment. Furthermore, we present, as an application of our scheme, results for the electrical properties of AuF and XeAuF.
Coulomb-oscillator duality and 5-dimensional Coulomb problem
Karayan, K H
2003-01-01
It is shown that the Hurwitz transformation connects the eight-dimensional oscillator problem with the five-dimensional Coulomb problem. The hyperspherical and parabolic coordinates are applied for analyzing the five-dimensional Coulomb problem. We calculate the spherical and parabolic bases for this system, derive the Park's and Tarter's representations for the coefficients of the spherical-parabolic and parabolic-spherical interbasis expansions
VISSER, O; VISSCHER, L; AERTS, PJC; NIEUWPOORT, WC
1992-01-01
We present results of all-electron molecular relativistic (Hartree-Fock-Dirac) and nonrelativistic (Hartree-Fock) calculations followed by a complete open shell configuration interaction (COSCI) calculation on an EuO6(9-) cluster in a Ba2GdNbO6 crystal. The results include the calculated energies of
Coulomb collisional relaxation process of ion beams in magnetized plasmas
Nishimura, Y.
2010-01-01
An orbit following code is developed to calculate ion beam trajectories in magnetized plasmas. The equation of motion (the Newton's equation) is solved including the Lorentz force term and Coulomb collisional relaxation term. Furthermore, a new algorithm is introduced by applying perturbation method regarding the collision term as a small term. The reduction of computation time is suggested.
Coulomb branch localization in quiver quantum mechanics
Energy Technology Data Exchange (ETDEWEB)
Ohta, Kazutoshi; Sasai, Yuya [Institute of Physics, Meiji Gakuin University,1518 Kamikurata-cho, Yokohama, 244-8539 (Japan)
2016-02-16
We show how to exactly calculate the refined indices of N=4U(1)×U(N) supersymmetric quiver quantum mechanics in the Coulomb branch by using the localization technique. The Coulomb branch localization is discussed from the viewpoint of both non-linear and gauged linear sigma models. A classification of fixed points in the Coulomb branch differs from one in the Higgs branch, but the derived indices completely agree with the results which were obtained by the localization in the Higgs branch. In the Coulomb branch localization, the refined indices can be written as a summation over different sets of the Coulomb branch fixed points. We also discuss a space-time picture of the fixed points in the Coulomb branch.
Directory of Open Access Journals (Sweden)
Staszczuk Anna
2016-06-01
Full Text Available The paper provides verification of 3D transient ground-coupled model to calculation of heat exchange between ground and typical one-storey, passive residential building. The model was performed with computer software WUFI®plus and carried out to estimate the indoor air temperatures during extending hot weather periods. For verifying the results of calculations performed by the WUFI®plus software, the most recent version of EnergyPlus software version was used. Comparison analysis of calculation results obtained with the two above mentioned calculation method was made for two scenarios of slab on ground constructions: without thermal insulation and with thermal insulation under the whole slab area. Comprehensive statistical analysis was done including time series analysis and descriptive statistics parameters.
Sanchez-Parcerisa, D.; Cortés-Giraldo, M. A.; Dolney, D.; Kondrla, M.; Fager, M.; Carabe, A.
2016-02-01
In order to integrate radiobiological modelling with clinical treatment planning for proton radiotherapy, we extended our in-house treatment planning system FoCa with a 3D analytical algorithm to calculate linear energy transfer (LET) in voxelized patient geometries. Both active scanning and passive scattering delivery modalities are supported. The analytical calculation is much faster than the Monte-Carlo (MC) method and it can be implemented in the inverse treatment planning optimization suite, allowing us to create LET-based objectives in inverse planning. The LET was calculated by combining a 1D analytical approach including a novel correction for secondary protons with pencil-beam type LET-kernels. Then, these LET kernels were inserted into the proton-convolution-superposition algorithm in FoCa. The analytical LET distributions were benchmarked against MC simulations carried out in Geant4. A cohort of simple phantom and patient plans representing a wide variety of sites (prostate, lung, brain, head and neck) was selected. The calculation algorithm was able to reproduce the MC LET to within 6% (1 standard deviation) for low-LET areas (under 1.7 keV μm-1) and within 22% for the high-LET areas above that threshold. The dose and LET distributions can be further extended, using radiobiological models, to include radiobiological effectiveness (RBE) calculations in the treatment planning system. This implementation also allows for radiobiological optimization of treatments by including RBE-weighted dose constraints in the inverse treatment planning process.
Sanchez-Parcerisa, D; Cortés-Giraldo, M A; Dolney, D; Kondrla, M; Fager, M; Carabe, A
2016-02-21
In order to integrate radiobiological modelling with clinical treatment planning for proton radiotherapy, we extended our in-house treatment planning system FoCa with a 3D analytical algorithm to calculate linear energy transfer (LET) in voxelized patient geometries. Both active scanning and passive scattering delivery modalities are supported. The analytical calculation is much faster than the Monte-Carlo (MC) method and it can be implemented in the inverse treatment planning optimization suite, allowing us to create LET-based objectives in inverse planning. The LET was calculated by combining a 1D analytical approach including a novel correction for secondary protons with pencil-beam type LET-kernels. Then, these LET kernels were inserted into the proton-convolution-superposition algorithm in FoCa. The analytical LET distributions were benchmarked against MC simulations carried out in Geant4. A cohort of simple phantom and patient plans representing a wide variety of sites (prostate, lung, brain, head and neck) was selected. The calculation algorithm was able to reproduce the MC LET to within 6% (1 standard deviation) for low-LET areas (under 1.7 keV μm(-1)) and within 22% for the high-LET areas above that threshold. The dose and LET distributions can be further extended, using radiobiological models, to include radiobiological effectiveness (RBE) calculations in the treatment planning system. This implementation also allows for radiobiological optimization of treatments by including RBE-weighted dose constraints in the inverse treatment planning process.
Bending of I-beam with the transvers shear effect included – FEM calculated
Energy Technology Data Exchange (ETDEWEB)
Grygorowicz, Magdalena; Lewiński, Jerzy [Poznan University of Technology, Institute of Applied Mechanics ul. Jana Pawła II No. 24, 60-138 Poznań POLAND (Poland)
2016-06-08
The paper is devoted to three-point bending of an I-beam with include of transvers shear effect. Numerical calculations were conducted independently with the use of the SolidWorks system and the multi-purpose software package ANSYS The results of FEM study conducted with the use of two systems were compared and presented in tables and figures.
Comparison of Two Prostate Cancer Risk Calculators that Include the Prostate Health Index
M.J. Roobol-Bouts (Monique); M.M. Vedder (Moniek); D. Nieboer (Daan); A. Houlgatte (Alain); S. Vincendeau (Sébastien); M. Lazzeri (Massimo); G. Guazzoni (Giorgio); C. Stephan (Carsten); A. Semjonow (Axel); A. Haese (Alexander); M. Graefen (Markus); E.W. Steyerberg (Ewout)
2015-01-01
textabstractBackground: Risk prediction models for prostate cancer (PCa) have become important tools in reducing unnecessary prostate biopsies. The Prostate Health Index (PHI) may increase the predictive accuracy of such models. Objectives: To compare two PCa risk calculators (RCs) that include PHI.
Hot DA white dwarf model atmosphere calculations: including improved Ni PI cross-sections
Preval, S. P.; Barstow, M. A.; Badnell, N. R.; Hubeny, I.; Holberg, J. B.
2017-02-01
To calculate realistic models of objects with Ni in their atmospheres, accurate atomic data for the relevant ionization stages need to be included in model atmosphere calculations. In the context of white dwarf stars, we investigate the effect of changing the Ni IV-VI bound-bound and bound-free atomic data on model atmosphere calculations. Models including photoionization cross-section (PICS) calculated with AUTOSTRUCTURE show significant flux attenuation of up to ˜80 per cent shortward of 180 Å in the extreme ultraviolet (EUV) region compared to a model using hydrogenic PICS. Comparatively, models including a larger set of Ni transitions left the EUV, UV, and optical continua unaffected. We use models calculated with permutations of these atomic data to test for potential changes to measured metal abundances of the hot DA white dwarf G191-B2B. Models including AUTOSTRUCTURE PICS were found to change the abundances of N and O by as much as ˜22 per cent compared to models using hydrogenic PICS, but heavier species were relatively unaffected. Models including AUTOSTRUCTURE PICS caused the abundances of N/O IV and V to diverge. This is because the increased opacity in the AUTOSTRUCTURE PICS model causes these charge states to form higher in the atmosphere, more so for N/O V. Models using an extended line list caused significant changes to the Ni IV-V abundances. While both PICS and an extended line list cause changes in both synthetic spectra and measured abundances, the biggest changes are caused by using AUTOSTRUCTURE PICS for Ni.
Lista, L
2004-01-01
A procedure to include the uncertainty on the background estimate for upper limit calculations using Poissonian sampling is presented for the case where a Gaussian assumption on the uncertainty can be made. Under that hypothesis an analytic expression of the likelihood is derived which can be written in terms of polynomials defined by recursion. This expression may lead to a significant speed up of computing applications that extract the upper limits using Toy Monte Carlo.
Coulomb dissociation of N,2120
Röder, Marko; Adachi, Tatsuya; Aksyutina, Yulia; Alcantara, Juan; Altstadt, Sebastian; Alvarez-Pol, Hector; Ashwood, Nicholas; Atar, Leyla; Aumann, Thomas; Avdeichikov, Vladimir; Barr, M.; Beceiro, Saul; Bemmerer, Daniel; Benlliure, Jose; Bertulani, Carlos; Boretzky, Konstanze; Borge, Maria J. G.; Burgunder, G.; Caamaño, Manuel; Caesar, Christoph; Casarejos, Enrique; Catford, Wilton; Cederkäll, Joakim; Chakraborty, S.; Chartier, Marielle; Chulkov, Leonid; Cortina-Gil, Dolores; Crespo, Raquel; Datta Pramanik, Ushasi; Diaz-Fernandez, Paloma; Dillmann, Iris; Elekes, Zoltan; Enders, Joachim; Ershova, Olga; Estrade, A.; Farinon, F.; Fraile, Luis M.; Freer, Martin; Freudenberger, M.; Fynbo, Hans; Galaviz, Daniel; Geissel, Hans; Gernhäuser, Roman; Göbel, Kathrin; Golubev, Pavel; Gonzalez Diaz, D.; Hagdahl, Julius; Heftrich, Tanja; Heil, Michael; Heine, Marcel; Heinz, Andreas; Henriques, Ana; Holl, Matthias; Ickert, G.; Ignatov, Alexander; Jakobsson, Bo; Johansson, Hâkan; Jonson, Björn; Kalantar-Nayestanaki, Nasser; Kanungo, Rituparna; Kelic-Heil, Aleksandra; Knöbel, Ronja; Kröll, Thorsten; Krücken, Reiner; Kurcewicz, J.; Kurz, Nikolaus; Labiche, Marc; Langer, Christoph; Le Bleis, Tudi; Lemmon, Roy; Lepyoshkina, Olga; Lindberg, Simon; Machado, Jorge; Marganiec, Justyna; Mostazo Caro, Magdalena; Movsesyan, Alina; Najafi, Mohammad Ali; Nilsson, Thomas; Nociforo, Chiara; Panin, Valerii; Paschalis, Stefanos; Perea, Angel; Petri, Marina; Pietri, S.; Plag, Ralf; Prochazka, A.; Rahaman, Md. Anisur; Rastrepina, Ganna; Reifarth, Rene; Ribeiro, Guillermo; Ricciardi, M. Valentina; Rigollet, Catherine; Riisager, Karsten; Rossi, Dominic; Sanchez del Rio Saez, Jose; Savran, Deniz; Scheit, Heiko; Simon, Haik; Sorlin, Olivier; Stoica, V.; Streicher, Branislav; Taylor, Jon; Tengblad, Olof; Terashima, Satoru; Thies, Ronja; Togano, Yasuhiro; Uberseder, Ethan; Van de Walle, J.; Velho, Paulo; Volkov, Vasily; Wagner, Andreas; Wamers, Felix; Weick, Helmut; Weigand, Mario; Wheldon, Carl; Wilson, G.; Wimmer, Christine; Winfield, J. S.; Woods, Philip; Yakorev, Dmitry; Zhukov, Mikhail; Zilges, Andreas; Zuber, Kai; R3B Collaboration
2016-06-01
Neutron-rich light nuclei and their reactions play an important role in the creation of chemical elements. Here, data from a Coulomb dissociation experiment on N,2120 are reported. Relativistic N,2120 ions impinged on a lead target and the Coulomb dissociation cross section was determined in a kinematically complete experiment. Using the detailed balance theorem, the 19N (n ,γ )20N and 20N (n ,γ ) 21N excitation functions and thermonuclear reaction rates have been determined. The 19 (n ,γ )20N rate is up to a factor of 5 higher at T <1 GK with respect to previous theoretical calculations, leading to a 10% decrease in the predicted fluorine abundance.
National Aeronautics and Space Administration — BRO will provide commercially available optics software that dependably calculates image plane irradiance to the precision required by TPF missions. Calculations...
Sample size calculations for randomised trials including both independent and paired data.
Yelland, Lisa N; Sullivan, Thomas R; Price, David J; Lee, Katherine J
2017-04-15
Randomised trials including a mixture of independent and paired data arise in many areas of health research, yet methods for determining the sample size for such trials are lacking. We derive design effects algebraically assuming clustering because of paired data will be taken into account in the analysis using generalised estimating equations with either an independence or exchangeable working correlation structure. Continuous and binary outcomes are considered, along with three different methods of randomisation: cluster randomisation, individual randomisation and randomisation to opposite treatment groups. The design effect is shown to depend on the intracluster correlation coefficient, proportion of observations belonging to a pair, working correlation structure, type of outcome and method of randomisation. The derived design effects are validated through simulation and example calculations are presented to illustrate their use in sample size planning. These design effects will enable appropriate sample size calculations to be performed for future randomised trials including both independent and paired data. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.
Brunelle, P; Sorensen, T S; Taeschler, C
2001-11-02
The structure of the camphenyl cation 1 has been studied in detail, using both experimental and computational approaches. Like others, we find only one structure on the camphenyl-isobornyl cation PE surface, but this single structure shows some unusual features. These include a very soft PE surface for movement along the C2-C6 axis (a nonbonding distance in a classical description of the cation), and a result of this is that very high computational methods (optimization at MP4 or QCI levels) are required in order to get structural minima that "fit" the experimental data. This PE surface has been probed computationally using fixed C2-C6 distances, and when one also calculates chemical shifts for these "fixed" structures, one sees calculated (13)C NMR chemical shifts for the C2 carbon that are hugely dependent on this fixed distance value, giving near-linear slopes of ca. 25 ppm/0.1 A distance change. Since this distance can vary over at least 0.6 A with relatively small calculated energy changes, there is a total range of ca. 150 ppm involved here. In a second part of this work, and in response to a recent paper in which the historic Meerwein "carbocation intermediate" proposal was rejected, we have calculated solvation energies (SCI-PCM method) for four carbocation systems, including 1. We find carbocation solvation energies (epsilon = 10 "solvent") of 45-53 kcal/mol, and where comparison can be made, the data correlate well with the literature. On the basis of these results, we re-affirm the Meerwein "carbocation" mechanism, but in order to accommodate only a single carbocation intermediate, we offer a description that amounts to a subtle variation of both the nonclassical ion proposal and Meerwein's "two cation" mechanism, namely that the camphenyl cation, 1, as a ground-state structure, can be described as only very weakly interacting in the C2-C6 bridging sense, but that the PE surface along this "bond" is so shallow that an energy input of only 4-6 kcal
A Coulomb-Like Off-Shell T-Matrix with the Correct Coulomb Phase Shift
Oryu, Shinsho; Watanabe, Takashi; Hiratsuka, Yasuhisa; Togawa, Yoshio
2017-03-01
We confirm the reliability of the well-known Coulomb renormalization method (CRM). It is found that the CRM is only available for a very-long-range screened Coulomb potential (SCP). However, such an SCP calculation in momentum space is considerably difficult because of the cancelation of significant digits. In contrast to the CRM, we propose a new method by using an on-shell equivalent SCP and the rest term. The two-potential theory with r-space is introduced, which defines fully the off-shell Coulomb amplitude.
Multi-reference approach to the calculation of photoelectron spectra including spin-orbit coupling
Grell, Gilbert; Winter, Bernd; Seidel, Robert; Aziz, Emad F; Aziz, Saadullah G; Kühn, Oliver
2015-01-01
X-ray photoelectron spectra provide a wealth of information on the electronic structure. The extraction of molecular details requires adequate theoretical methods, which in case of transition metal complexes has to account for effects due to the multi-configurational and spin-mixed nature of the many-electron wave function. Here, the Restricted Active Space Self-Consistent Field method including spin-orbit coupling is used to cope with this challenge and to calculate valence and core photoelectron spectra. The intensities are estimated within the frameworks of the Dyson orbital formalism and the sudden approximation. Thereby, we utilize an efficient computational algorithm that is based on a biorthonormal basis transformation. The approach is applied to the valence photoionization of the gas phase water molecule and to the core ionization spectrum of the $\\text{[Fe(H}_2\\text{O)}_6\\text{]}^{2+}$ complex. The results show good agreement with the experimental data obtained in this work, whereas the sudden approx...
Plasmons in Dimensionally Mismatched Coulomb Coupled Graphene Systems
DEFF Research Database (Denmark)
Badalyan, S. M.; Shylau, A. A.; Jauho, Antti-Pekka
2017-01-01
We calculate the plasmon dispersion relation for Coulomb coupled metallic armchair graphene nanoribbons and doped monolayer graphene. The crossing of the plasmon curves, which occurs for uncoupled 1D and 2D systems, is split by the interlayer Coulomb coupling into a lower and an upper plasmon...... by varying the system parameters and be used in plasmonic applications....
Evaluation of negative energy Coulomb (Whittaker) functions
Noble, C. J.
2004-05-01
This paper describes a code for evaluating exponentially decaying negative energy Coulomb functions and their first derivatives with respect to the radial variable. The functions, which correspond to Whittaker functions of the second kind, are obtained to high accuracy for a wide range of parameters using recurrence techniques. Program summaryTitle of program: whittaker_w Catalog identifier: ADSZ Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADSZ Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Computer: Cray T3E, Sun Ultra-5_10 sparc, Origin2000, Compaq EV67, IBM SP3, Toshiba 460CDT Operating systems under which the program has been tested: Windows NT4, Redhat Linux, SunOS 5.8 Programming language used: Fortran 95 Memory required to run with typical data: 500 KB Number of bytes in distributed program, including test data, etc.: 39728 Number of lines in distributed program, including test data, etc.: 2900 Distribution format: tar gzip file Nature of physical problem: The closed-channel components of the asymptotic radial wave function corresponding to electron or positron scattering by atomic or molecular ions may be expressed in terms of negative energy Coulomb functions. The scattering observables are obtained from S or T matrices which in turn are obtained by matching the radial and asymptotic wavefunctions at a finite radial point. Recent large scale scattering calculations have required accurate values of the Coulomb functions at smaller ρ values and larger negative η values than previous work. The present program is designed to extend the range of parameters for which the function may be calculated. Method of solution: Recurrence relations, power series expansion, numerical quadrature. Restrictions on the complexity of the problem: The program has been tested for the parameter ranges: 0< ρ⩽1000, | η|⩽120 and 0⩽ l⩽100. These ranges may, with appropriate scaling to avoid underflow and overflow, be
Energy Technology Data Exchange (ETDEWEB)
Carlen, Ida; Nikolopoulos, Anna; Isaeus, Martin (AquaBiota Water Research, Stockholm (SE))
2007-06-15
GIS grids (maps) of marine parameters were created using point data from previous site investigations in the Forsmark and Oskarshamn areas. The proportion of global radiation reaching the sea bottom in Forsmark and Oskarshamn was calculated in ArcView, using Secchi depth measurements and the digital elevation models for the respective area. The number of days per year when the incoming light exceeds 5 MJ/m2 at the bottom was then calculated using the result of the previous calculations together with measured global radiation. Existing modelled grid-point data on bottom and pelagic temperature for Forsmark were interpolated to create surface covering grids. Bottom and pelagic temperature grids for Oskarshamn were calculated using point measurements to achieve yearly averages for a few points and then using regressions with existing grids to create new maps. Phytoplankton primary production in Forsmark was calculated using point measurements of chlorophyll and irradiance, and a regression with a modelled grid of Secchi depth. Distribution of biomass of macrophyte communities in Forsmark and Oskarshamn was calculated using spatial modelling in GRASP, based on field data from previous surveys. Physical parameters such as those described above were used as predictor variables. Distribution of biomass of different functional groups of fish in Forsmark was calculated using spatial modelling based on previous surveys and with predictor variables such as physical parameters and results from macrophyte modelling. All results are presented as maps in the report. The quality of the modelled predictions varies as a consequence of the quality and amount of the input data, the ecology and knowledge of the predicted phenomena, and by the modelling technique used. A substantial part of the variation is not described by the models, which should be expected for biological modelling. Therefore, the resulting grids should be used with caution and with this uncertainty kept in mind. All
Stanke, Monika; Adamowicz, Ludwik
2014-10-01
We report very accurate calculations of the complete pure vibrational spectrum of the T2 molecule with an approach where the Born-Oppenheimer (BO) approximation is not assumed. As the considered states correspond to the zero total angular momentum, their non-BO wave functions are spherically symmetric and are expanded in terms of all-particle, one-center, spherically symmetric explicitly correlated Gaussian functions multiplied by even nonnegative powers of the internuclear distance. The nonrelativistic energies of the states obtained in the non-BO calculations are corrected for the relativistic effects of the order of α2 (where α is the fine structure constant) calculated as expectation values of the operators representing these effects.
Stanke, Monika; Adamowicz, Ludwik
2014-10-21
We report very accurate calculations of the complete pure vibrational spectrum of the T2 molecule with an approach where the Born-Oppenheimer (BO) approximation is not assumed. As the considered states correspond to the zero total angular momentum, their non-BO wave functions are spherically symmetric and are expanded in terms of all-particle, one-center, spherically symmetric explicitly correlated Gaussian functions multiplied by even nonnegative powers of the internuclear distance. The nonrelativistic energies of the states obtained in the non-BO calculations are corrected for the relativistic effects of the order of α(2) (where α is the fine structure constant) calculated as expectation values of the operators representing these effects.
Hybrid and Constrained Resolution-of-Identity Techniques for Coulomb Integrals.
Duchemin, Ivan; Li, Jing; Blase, Xavier
2017-03-14
The introduction of auxiliary bases to approximate molecular orbital products has paved the way to significant savings in the evaluation of four-center two-electron Coulomb integrals. We present a generalized dual space strategy that sheds a new light on variants over the standard density and Coulomb-fitting schemes, including the possibility of introducing minimization constraints. We improve in particular the charge- or multipole-preserving strategies introduced respectively by Baerends and Van Alsenoy that we compare to a simple scheme where the Coulomb metric is used for lowest angular momentum auxiliary orbitals only. We explore the merits of these approaches on the basis of extensive Hartree-Fock and MP2 calculations over a standard set of medium size molecules.
Garberoglio, Giovanni; Jankowski, Piotr; Szalewicz, Krzysztof; Harvey, Allan H
2014-07-28
We present a path-integral Monte Carlo procedure for the fully quantum calculation of the second molecular virial coefficient accounting for intramolecular flexibility. This method is applied to molecular hydrogen (H2) and deuterium (D2) in the temperature range 15-2000 K, showing that the effect of molecular flexibility is not negligible. Our results are in good agreement with experimental data, as well as with virials given by recent empirical equations of state, although some discrepancies are observed for H2 between 100 and 200 K.
Energy Technology Data Exchange (ETDEWEB)
Garberoglio, Giovanni, E-mail: garberoglio@fbk.eu [Interdisciplinary Laboratory for Computational Science (LISC), FBK-CMM and University of Trento, via Sommarive 18, I-38123 Povo (Italy); Jankowski, Piotr [Department of Quantum Chemistry, Faculty of Chemistry, Nicolaus Copernicus University, Gagarina 7, PL-87-100 Toruń (Poland); Szalewicz, Krzysztof [Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States); Harvey, Allan H. [Applied Chemicals and Materials Division, National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305-3337 (United States)
2014-07-28
We present a path-integral Monte Carlo procedure for the fully quantum calculation of the second molecular virial coefficient accounting for intramolecular flexibility. This method is applied to molecular hydrogen (H{sub 2}) and deuterium (D{sub 2}) in the temperature range 15–2000 K, showing that the effect of molecular flexibility is not negligible. Our results are in good agreement with experimental data, as well as with virials given by recent empirical equations of state, although some discrepancies are observed for H{sub 2} between 100 and 200 K.
Energy Technology Data Exchange (ETDEWEB)
Avancini, S.S.; Marinelli, J.R. [Universidade Federal de Santa Catarina Florianopolis, Depto de Fisica - CFM, Florianopolis (Brazil); Carlson, B.V. [Instituto Tecnologico de Aeronautica, Sao Jose dos Campos (Brazil)
2013-06-15
Relativistic models for finite nuclei contain spurious center-of-mass motion in most applications for the nuclear many-body problem, where the nuclear wave function is taken as a single Slater determinant within a space-fixed frame description. We use the Peierls-Yoccoz projection method, previously developed for relativistic approaches together with a reparametrization of the coupling constants that fits binding energies and charge radius and apply our results to calculate elastic electron scattering monopole charge form factors for light nuclei. (orig.)
Elastic scattering of sup 58 Ni+ sup 64 Ni near the Coulomb barrier
Energy Technology Data Exchange (ETDEWEB)
Stefanini, A.M.; Xu Jincheng; Corradi, L.; Montagnoli, G.; Moreno, H.; Nagashima, Y.; Mueller, L.; Narayanasamy, M.; Napoli, D.R.; Spolaore, P. (Istituto Nazionale di Fisica Nucleare, Padua (Italy). Lab. di Legnaro); Beghini, S.; Scarlassara, F.; Segato, G.F.; Soramel, F. (Padua Univ. (Italy). Dipt. di Fisica Istituto Nazionale di Fisica Nucleare, Padua (Italy)); Signorini, C. (Salerno Univ. (Italy). Dipt. di Fisica Istituto Nazionale di Fisica Nucleare, Padua (Italy)); Esbensen, H.; Landowne, S. (Argonne National Lab., IL (USA). Physics Div.); Pollarolo, G. (Turin Univ. (Italy). Dipt. di Fisica Istituto Nazionale di Fisica Nucleare, Turin (Italy))
1990-04-26
Elastic scattering angular distributions have been measured for {sup 58}Ni+{sup 64}Ni at three energies around the Coulomb barrier employing a new kinematic coincidence technique. The data are compared with the results of coupled-channels calculations including inelastic excitations as well as one- and two-neutron transfer reactions. The agreement is good and the calculations also agree well with the available transfer and fusion reaction data. (orig.).
Energy Technology Data Exchange (ETDEWEB)
Komninos, Yannis [Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vasileos Constantinou Avenue, Athens 11635 (Greece); Nicolaides, Cleanthes A [Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vasileos Constantinou Avenue, Athens 11635 (Greece)
2004-05-14
In continuation of our earlier work on the ab initio calculation of perturbed spectra and on a corresponding quantum defect theory (QDT), we discuss certain essential characteristics having to do with the unification of the continuous and the discrete spectra via the formal and practical construction of smooth quantities without invoking the pair of analytic forms of regular and irregular functions. The theory and its computational methodology are in the framework of configuration interaction (CI), and its structure shows how wavefunctions and properties of excited states of atoms and molecules can be computed provided one uses reliable zero-order basis functions, regardless of whether the relevant potential is, asymptotically, Coulombic or some other type. The mathematical connection with smooth reaction matrices in the discrete spectrum is demonstrated via the Mittag-Leffler theorem for the construction of analytic functions. We compare results for the quantum defects and fine structure from the present theory, as implemented by Komninos et al ( 1995 J. Phys. B: At. Mol. Opt. Phys. 28 2049 , 1996 J. Phys. B: At. Mol. Opt. Phys. 29 L193 ), of the Al spectra of {sup 2} D symmetry (strongly perturbed) and of {sup 2} F {sup o} symmetry (weakly perturbed), with the recently reported measurements on high-lying states ( Dyubko et al 2003 J. Phys. B: At. Mol. Opt. Phys. 36 3797 and 4827 ), as well as with those of Eriksson and Isberg (1963 Ark. Fys. 23 527) for the low-lying states. The comparison reveals for the first time very good agreement between theory and experiment for both series. In addition, predictions for the other states of the series are made. Previous computations of the quantum defects of the {sup 2} D spectrum, in general, do not agree among themselves while they deviate from the experimental values.
Microscopic age determination of human skeletons including an unknown but calculable variable
DEFF Research Database (Denmark)
Wallin, Johan Albert; Tkocz, Izabella; Kristensen, Gustav
1994-01-01
estimation, which includes the covariance matrix of four single equation residuals, improves the accuracy of age determination. The standard deviation, however, of age prediction remains 12.58 years. An experimental split of the data was made in order to demonstrate that the use of subgroups gives a false...
Lovato, Alessandro
2012-10-01
In this thesis, the ground state properties of nuclear matter, namely the energy per particle and the response to weak probes, are computed, studying the effects of three nucleon interactions. Both the variational approach, based on the formalism of correlated basis function, and the auxiliary field diffusion Monte Carlo method have been used. A scheme suitable to construct a density-dependent two-nucleon potential in correlated basis approach is discussed. The density dependent potential resulting from UIX three-nucleon force has been employed in auxiliary field diffusion Monte Carlo calculations that turned out to be in very good agreement with correlated basis variational results. Hence, the underbinding of symmetric nuclear matter has to be ascribed to deficiencies of the UXI potential. A comparative analysis of the equations of state of both pure neutron matter and symmetric nuclear matter obtained using a new generation of "chiral inspired" local three-body potentials has been performed. These potentials provide an excellent description of the properties of light nuclei, as well as of the neutron-deuteron doublet scattering length. The weak response of symmetric nuclear matter has been computed at three-body cluster level. Two-body effective interactions and one-body effective operators have been derived within the formalism of correlated basis functions. The inclusion of the three-body cluster term in the effective interaction allowed for a direct inclusion of the UIX three-nucleon potential. Moreover, the sizable unphysical dependence of the effective weak operator is removed once the three-body cluster term is taken into account.
Water dimer equilibrium constant calculation: a quantum formulation including metastable states.
Leforestier, Claude
2014-02-21
We present a full quantum evaluation of the water second virial coefficient B(T) based on the Takahashi-Imada second order approximation. As the associated trace T r[e(-βH(AB)) - e(-βH(0)(AB))] is performed in the coordinate representation, it does also include contribution from the whole continuum, i.e., resonances and collision pairs of monomers. This approach is compared to a Path Integral Monte Carlo evaluation of this coefficient by Schenter [J. Chem. Phys. 117, 6573 (2002)] for the TIP4P potential and shown to give extremely close results in the low temperature range (250-450 K) reported. Using a recent ab initio flexible potential for the water dimer, this new formulation leads to very good agreement with experimental values over the whole range of temperatures available. The virial coefficient is then used in the well known relation Kp(T) = -(B(T) - bM)/RT where the excluded volume bM is assimilated to the second virial coefficient of pure water monomer vapor and approximated from the inner repulsive part of the interaction potential. This definition, which renders bM temperature dependent, allows us to retrieve the 38 cm(3) mol(-1) value commonly used, at room temperature. The resulting values for Kp(T) are in agreement with available experimental data obtained from infrared absorption spectra of water vapor.
Water dimer equilibrium constant calculation: A quantum formulation including metastable states
Energy Technology Data Exchange (ETDEWEB)
Leforestier, Claude, E-mail: claude.leforestier@univ-montp2.fr [Institut Charles Gerhardt, CNRS 5253, CC 15.01, Université Montpellier II-CNRS, 34095 Montpellier Cedex 05 (France)
2014-02-21
We present a full quantum evaluation of the water second virial coefficient B(T) based on the Takahashi-Imada second order approximation. As the associated trace Tr[e{sup −βH{sub A}{sub B}}−e{sup −βH{sub A}{sub B}{sup o}}] is performed in the coordinate representation, it does also include contribution from the whole continuum, i.e., resonances and collision pairs of monomers. This approach is compared to a Path Integral Monte Carlo evaluation of this coefficient by Schenter [J. Chem. Phys. 117, 6573 (2002)] for the TIP4P potential and shown to give extremely close results in the low temperature range (250–450 K) reported. Using a recent ab initio flexible potential for the water dimer, this new formulation leads to very good agreement with experimental values over the whole range of temperatures available. The virial coefficient is then used in the well known relation K{sub p}(T) = −(B(T) − b{sub M})/RT where the excluded volume b{sub M} is assimilated to the second virial coefficient of pure water monomer vapor and approximated from the inner repulsive part of the interaction potential. This definition, which renders b{sub M} temperature dependent, allows us to retrieve the 38 cm{sup 3} mol{sup −1} value commonly used, at room temperature. The resulting values for K{sub p}(T) are in agreement with available experimental data obtained from infrared absorption spectra of water vapor.
Takayanagi, K.; Lipparini, E.
1995-07-01
The Dyson equation for the particle-hole Green's function, including Coulomb exchange matrix elements, has been solved exactly for a two-dimensional electron gas. Static and dynamic dielectric functions have been calculated and compared with normal random-phase-approximation and recent quantum Monte Carlo results.
Kinetic theory for strongly coupled Coulomb systems
Dufty, James; Wrighton, Jeffrey
2018-01-01
The calculation of dynamical properties for matter under extreme conditions is a challenging task. The popular Kubo-Greenwood model exploits elements from equilibrium density-functional theory (DFT) that allow a detailed treatment of electron correlations, but its origin is largely phenomenological; traditional kinetic theories have a more secure foundation but are limited to weak ion-electron interactions. The objective here is to show how a combination of the two evolves naturally from the short-time limit for the generator of the effective single-electron dynamics governing time correlation functions without such limitations. This provides a theoretical context for the current DFT-related approach, the Kubo-Greenwood model, while showing the nature of its corrections. The method is to calculate the short-time dynamics in the single-electron subspace for a given configuration of the ions. This differs from the usual kinetic theory approach in which an average over the ions is performed as well. In this way the effective ion-electron interaction includes strong Coulomb coupling and is shown to be determined from DFT. The correlation functions have the form of the random-phase approximation for an inhomogeneous system but with renormalized ion-electron and electron-electron potentials. The dynamic structure function, density response function, and electrical conductivity are calculated as examples. The static local field corrections in the dielectric function are identified in this way. The current analysis is limited to semiclassical electrons (quantum statistical potentials), so important quantum conditions are excluded. However, a quantization of the kinetic theory is identified for broader application while awaiting its detailed derivation.
DEFF Research Database (Denmark)
Mogensen, Lisbeth; Kristensen, Troels; Nguyen, T Lan T
2014-01-01
Greenhouse gas emissions (GHG) related to feed production is one of the hotspots in livestock production. The aim of this paper was to estimate the carbon footprint of different feedstuffs for dairy cattle using life cycle assessment (LCA). The functional unit was ‘1 kg dry matter (DM) of feed...... fodder crop, an individual production scheme was set up as the basis for calculating the carbon footprint (CF). In the calculations, all fodder crops were fertilized by artificial fertilizer based on the assumption that the environmental burden of using manure is related to the livestock production...... ready to feed’. Included in the study were fodder crops that are grown in Denmark and typically used on Danish cattle farms. The contributions from the growing, processing and transport of feedstuffs were included, as were the changes in soil carbon (soil C) and from land use change (LUC). For each...
Zheng, Jingjing; Mielke, Steven L.; Clarkson, Kenneth L.; Truhlar, Donald G.
2012-08-01
We present a Fortran program package, MSTor, which calculates partition functions and thermodynamic functions of complex molecules involving multiple torsional motions by the recently proposed MS-T method. This method interpolates between the local harmonic approximation in the low-temperature limit, and the limit of free internal rotation of all torsions at high temperature. The program can also carry out calculations in the multiple-structure local harmonic approximation. The program package also includes six utility codes that can be used as stand-alone programs to calculate reduced moment of inertia matrices by the method of Kilpatrick and Pitzer, to generate conformational structures, to calculate, either analytically or by Monte Carlo sampling, volumes for torsional subdomains defined by Voronoi tessellation of the conformational subspace, to generate template input files, and to calculate one-dimensional torsional partition functions using the torsional eigenvalue summation method. Catalogue identifier: AEMF_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEMF_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.: 77 434 No. of bytes in distributed program, including test data, etc.: 3 264 737 Distribution format: tar.gz Programming language: Fortran 90, C, and Perl Computer: Itasca (HP Linux cluster, each node has two-socket, quad-core 2.8 GHz Intel Xeon X5560 “Nehalem EP” processors), Calhoun (SGI Altix XE 1300 cluster, each node containing two quad-core 2.66 GHz Intel Xeon “Clovertown”-class processors sharing 16 GB of main memory), Koronis (Altix UV 1000 server with 190 6-core Intel Xeon X7542 “Westmere” processors at 2.66 GHz), Elmo (Sun Fire X4600 Linux cluster with AMD Opteron cores), and Mac Pro (two 2.8 GHz Quad-core Intel Xeon
Ionic Coulomb Blockade and Resonant Conduction in Biological Ion Channels
Kaufman, I Kh; Eisenberg, R S
2014-01-01
The conduction and selectivity of calcium/sodium ion channels are described in terms of ionic Coulomb blockade, a phenomenon based on charge discreteness and an electrostatic model of an ion channel. This novel approach provides a unified explanation of numerous observed and modelled conductance and selectivity phenomena, including the anomalous mole fraction effect and discrete conduction bands. Ionic Coulomb blockade and resonant conduction are similar to electronic Coulomb blockade and resonant tunnelling in quantum dots. The model is equally applicable to other nanopores.
Enhanced population of side band of {sup 155}Gd in heavy-ion Coulomb excitation
Energy Technology Data Exchange (ETDEWEB)
Oshima, Masumi; Hayakawa, Takehito; Hatsukawa, Yuichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] [and others
1998-03-01
In the Coulomb excitation of {sup 155}Gd with heavy projectiles, {sup 32}S, {sup 58}Ni and {sup 90}Zr, unexpectedly large enhancement of a positive-parity side band has been observed. This enhancement could not be reproduced by a Coulomb-excitation calculation taking into account the recommended upper limits of E1 or E3 transitions, which are compiled in the whole mass region, and is proportional to the electric field accomplished in the Coulomb-scattering process. (author)
Phase-function method for Coulomb-distorted nuclear scattering
Energy Technology Data Exchange (ETDEWEB)
Sett, G.C.; Laha, U.; Talukdar, B.
1988-09-21
The phase-function method is very effective in treating quantum mechanical scattering problems for short-range local potentials. We adapt the phase method to deal with Coulomb plus Graz non-local separable potentials and derive a closed-form expression for the scattering phase shift. Our approach to the problem circumvents in a rather natural way the typical difficulties of incorporating the Coulomb interaction in a nuclear phase-shift calculation. We demonstrate the usefulness of our constructed expression by means of a model calculation.
Energy Technology Data Exchange (ETDEWEB)
Pena, C.; Pellacani, F.; Macian Juan, R., E-mail: carlos.pena@ntech.mw.tum.de, E-mail: pellacani@ntech.mw.tum.de, E-mail: macian@ntech.mw.tum.de [Technische Universitaet Muenchen, Garching (Germany). Ntech Lehrstuhl fuer Nukleartechnik; Chiva, S., E-mail: schiva@emc.uji.es [Universitat Jaume I, Castellon de la Plana (Spain). Dept. de Ingenieria Mecanica y Construccion; Barrachina, T.; Miro, R., E-mail: rmiro@iqn.upv.es, E-mail: tbarrachina@iqn.upv.es [Universitat Politecnica de Valencia (ISIRYM/UPV) (Spain). Institute for Industrial, Radiophysical and Environmental Safety
2011-07-01
been developed for calculation and synchronization purposes. The data exchange is realized by means of the Parallel Virtual Machine (PVM) software package. In this contribution, steady-state and transient results of a quarter of PWR fuel assembly with cold water injection are presented and compared with obtained results from a RELAP5/PARCS v2.7 coupled calculation. A simplified model for the spacers has been included. A methodology has been introduced to take into account the pressure drop and the turbulence enhancement produced by the spacers. (author)
QCD Coulomb Gauge Approach to Exotic Hadrons
Cotanch, Stephen R.; General, Ignacio J.; Wang, Ping
2006-01-01
The Coulomb gauge Hamiltonian model is used to calculate masses for selected J^{PC} states consisting of exotic combinations of quarks and gluons: ggg glueballs (oddballs), q bar{q} g hybrid mesons and q bar{q} q bar{q} tetraquark systems. An odderon Regge trajectory is computed for the J^{--} glueballs with intercept much smaller than the pomeron, explaining its nonobservation. The lowest 1^{-+} hybrid meson mass is found to be just above 2.2 GeV while the lightest tetraquark state mass with...
Coulomb drag in multiwall armchair carbon nanotubes
DEFF Research Database (Denmark)
Lunde, A.M.; Jauho, Antti-Pekka
2004-01-01
We calculate the transresistivity rho(21) between two concentric armchair nanotubes in a diffusive multiwall carbon nanotube as a function of temperature T and Fermi level epsilon(F). We approximate the tight-binding band structure by two crossing bands with a linear dispersion near the Fermi...... surface. The cylindrical geometry of the nanotubes and the different parities of the Bloch states are accounted for in the evaluation of the effective Coulomb interaction between charges in the concentric nanotubes. We find a broad peak in rho(21) as a function of temperature at roughly T similar to 0.4T...
Energy Technology Data Exchange (ETDEWEB)
Breitschopf, Barbara [Fraunhofer Inst. for Systems and Innovation Research (Germany); Nathani, Carsten [Ruetter and Partner Socioeconomic Research and Consulting (Switzerland); Resch, Gustav [Vienna Univ. of Technology, Energy Economics Group (EEG) (Austria
2012-07-15
The EMPLOY project aimed to help achieve the IEA-RETD’s objective to 'empower policy makers and energy market actors through the provision of information, tools and resources' by underlining the economic and industrial impacts of renewable energy technology deployment and providing reliable methodological approaches for employment – similar to those available for the incumbent energy technologies. The EMPLOY project resulted in a comprehensive set of methodological guidelines for estimating the employment impacts of renewable energy deployment in a coherent, uniform and systematic way. Guidelines were prepared for four different methodological approaches. In the introduction section of the guidelines policy makers are guided in their choice for the most suited approach, depending on the policy questions to be answered, the data availability and budget. The guidelines were tested for the IEA-RETD member state countries and Tunisia. The results of these calculations are included in the annex to the guidelines.
Energy Technology Data Exchange (ETDEWEB)
David R. Farley
2010-08-19
A model has been developed to calculate the ground-state rotational populations of homonuclear diatomic molecules in kinetic gases, including the effects of electron-impact excitation, wall collisions, and gas feed rate. The equations are exact within the accuracy of the cross sections used and of the assumed equilibrating effect of wall collisions. It is found that the inflow of feed gas and equilibrating wall collisions can significantly affect the rotational distribution in competition with non-equilibrating electron-impact effects. The resulting steady-state rotational distributions are generally Boltzmann for N≥3, with a rotational temperature between the wall and feed gas temperatures. The N=0,1,2 rotational level populations depend sensitively on the relative rates of electron-impact excitation versus wall collision and gas feed rates.
Marsolat, F; De Marzi, L; Pouzoulet, F; Mazal, A
2016-01-21
In proton therapy, the relative biological effectiveness (RBE) depends on various types of parameters such as linear energy transfer (LET). An analytical model for LET calculation exists (Wilkens' model), but secondary particles are not included in this model. In the present study, we propose a correction factor, L sec, for Wilkens' model in order to take into account the LET contributions of certain secondary particles. This study includes secondary protons and deuterons, since the effects of these two types of particles can be described by the same RBE-LET relationship. L sec was evaluated by Monte Carlo (MC) simulations using the GATE/GEANT4 platform and was defined by the ratio of the LET d distributions of all protons and deuterons and only primary protons. This method was applied to the innovative Pencil Beam Scanning (PBS) delivery systems and L sec was evaluated along the beam axis. This correction factor indicates the high contribution of secondary particles in the entrance region, with L sec values higher than 1.6 for a 220 MeV clinical pencil beam. MC simulations showed the impact of pencil beam parameters, such as mean initial energy, spot size, and depth in water, on L sec. The variation of L sec with these different parameters was integrated in a polynomial function of the L sec factor in order to obtain a model universally applicable to all PBS delivery systems. The validity of this correction factor applied to Wilkens' model was verified along the beam axis of various pencil beams in comparison with MC simulations. A good agreement was obtained between the corrected analytical model and the MC calculations, with mean-LET deviations along the beam axis less than 0.05 keV μm(-1). These results demonstrate the efficacy of our new correction of the existing LET model in order to take into account secondary protons and deuterons along the pencil beam axis.
Norbury, John W.
Nuclear fission reactions induced by the electromagnetic field of relativistic nuclei are studied for energies relevant to present and future relativistic heavy ion accelerators. Cross sections are calculated for U-238 and Pu-239 fission induced by C-12, Si-28, Au-197, and U-238 projectiles. It is found that some of the cross sections can exceed 10 b.
Energy Technology Data Exchange (ETDEWEB)
Fang, Zongtang; Both, Johan; Li, Shenggang; Yue, Shuwen; Aprà, Edoardo; Keçeli, Murat; Wagner, Albert F.; Dixon, David A.
2016-08-09
The heats of formation and the normalized clustering energies (NCEs) for the group 4 and group 6 transition metal oxide (TMO) trimers and tetramers have been calculated by the Feller-Peterson-Dixon (FPD) method. The heats of formation predicted by the FPD method do not differ much from those previously derived from the NCEs at the CCSD(T)/aT level except for the CrO3 nanoclusters. New and improved heats of formation for Cr3O9 and Cr4O12 were obtained using PW91 orbitals instead of Hartree-Fock (HF) orbitals. Diffuse functions are necessary to predict accurate heats of formation. The fluoride affinities (FAs) are calculated with the CCSD(T) method. The relative energies (REs) of different isomers, NCEs, electron affinities (EAs), and FAs of (MO2)n ( M = Ti, Zr, Hf, n = 1 – 4 ) and (MO3)n ( M = Cr, Mo, W, n = 1 – 3) clusters have been benchmarked with 55 exchange-correlation DFT functionals including both pure and hybrid types. The absolute errors of the DFT results are mostly less than ±10 kcal/mol for the NCEs and the EAs, and less than ±15 kcal/mol for the FAs. Hybrid functionals usually perform better than the pure functionals for the REs and NCEs. The performance of the two types of functionals in predicting EAs and FAs is comparable. The B1B95 and PBE1PBE functionals provide reliable energetic properties for most isomers. Long range corrected pure functionals usually give poor FAs. The standard deviation of the absolute error is always close to the mean errors and the probability distributions of the DFT errors are often not Gaussian (normal). The breadth of the distribution of errors and the maximum probability are dependent on the energy property and the isomer.
Molecular integrals for slater type orbitals using coulomb sturmians
DEFF Research Database (Denmark)
Avery, James Emil; Avery, John Scales
2014-01-01
The use of Slater type orbitals in molecular calculations is hindered by the slowness of integral evaluation. In the present paper, we introduce a method for overcoming this problem by expanding STO's in terms of Coulomb Sturmians, for which the problem of evaluating molecular integrals rapidly has...
Intershell resistance in multiwall carbon nanotubes: A Coulomb drag study
DEFF Research Database (Denmark)
Lunde, Anders Mathias; Flensborg, Karsten; Jauho, Antti-Pekka
2005-01-01
We calculate the intershell resistance R-21 in a multiwall carbon nanotube as a function of temperature T and Fermi level epsilon(F) (e.g., a gate voltage), varying the chirality of the inner and outer tubes. This is done in a so-called Coulomb drag setup, where a current I-1 in one shell induces...... effects for the Coulomb drag between different tubes due to selection rules combined with mismatching of wave vector and crystal angular momentum conservation near the Fermi level. This gives rise to orders of magnitude changes in R-21 and even the sign of R-21 can change depending on the chirality...
Pouw, Maurice E; Peelen, L M; Moons, K G M; Kalkman, C J; Lingsma, H F
2013-10-21
To assess the consequences of applying different mortality timeframes on standardised mortality ratios of individual hospitals and, secondarily, to evaluate the association between in-hospital standardised mortality ratios and early post-discharge mortality rate, length of hospital stay, and transfer rate. Retrospective analysis of routinely collected hospital data to compare observed deaths in 50 diagnostic categories with deaths predicted by a case mix adjustment method. 60 Dutch hospitals. 1 228 815 patients discharged in the period 2008 to 2010. In-hospital standardised mortality ratio, 30 days post-admission standardised mortality ratio, and 30 days post-discharge standardised mortality ratio. Compared with the in-hospital standardised mortality ratio, 33% of the hospitals were categorised differently with the 30 days post-admission standardised mortality ratio and 22% were categorised differently with the 30 days post-discharge standardised mortality ratio. A positive association was found between in-hospital standardised mortality ratio and length of hospital stay (Pearson correlation coefficient 0.33; P=0.01), and an inverse association was found between in-hospital standardised mortality ratio and early post-discharge mortality (Pearson correlation coefficient -0.37; P=0.004). Applying different mortality timeframes resulted in differences in standardised mortality ratios and differences in judgment regarding the performance of individual hospitals. Furthermore, associations between in-hospital standardised mortality rates, length of stay, and early post-discharge mortality rates were found. Combining these findings suggests that standardised mortality ratios based on in-hospital mortality are subject to so-called "discharge bias." Hence, early post-discharge mortality should be included in the calculation of standardised mortality ratios.
Coulomb drag in quantum circuits.
Levchenko, Alex; Kamenev, Alex
2008-11-21
We study the drag effect in a system of two electrically isolated quantum point contacts, coupled by Coulomb interactions. Drag current exhibits maxima as a function of quantum point contacts gate voltages when the latter are tuned to the transitions between quantized conductance plateaus. In the linear regime this behavior is due to enhanced electron-hole asymmetry near an opening of a new conductance channel. In the nonlinear regime the drag current is proportional to the shot noise of the driving circuit, suggesting that the Coulomb drag experiments may be a convenient way to measure the quantum shot noise. Remarkably, the transition to the nonlinear regime may occur at driving voltages substantially smaller than the temperature.
Directory of Open Access Journals (Sweden)
R. Combescot
2017-11-01
Full Text Available We present a general approach for the solution of the three-body problem for a general interaction and apply it to the case of the Coulomb interaction. This approach is exact, simple, and fast. It makes use of integral equations derived from the consideration of the scattering properties of the system. In particular, this makes full use of the solution of the two-body problem, the interaction appearing only through the corresponding known T matrix. In the case of the Coulomb potential, we make use of a very convenient expression for the T matrix obtained by Schwinger. As a check, we apply this approach to the well-known problem of the helium atom ground state and obtain a perfect numerical agreement with the known result for the ground-state energy. The wave function is directly obtained from the corresponding solution. We expect our method to be, in particular, quite useful for the trion problem in semiconductors.
Bubin, Sergiy; Stanke, Monika; Adamowicz, Ludwik
2011-08-01
In this work we report very accurate variational calculations of the complete pure vibrational spectrum of the D2 molecule performed within the framework where the Born-Oppenheimer (BO) approximation is not assumed. After the elimination of the center-of-mass motion, D2 becomes a three-particle problem in this framework. As the considered states correspond to the zero total angular momentum, their wave functions are expanded in terms of all-particle, one-center, spherically symmetric explicitly correlated Gaussian functions multiplied by even non-negative powers of the internuclear distance. The nonrelativistic energies of the states obtained in the non-BO calculations are corrected for the relativistic effects of the order of α2 (where α = 1/c is the fine structure constant) calculated as expectation values of the operators representing these effects.
Bubin, Sergiy; Stanke, Monika; Adamowicz, Ludwik
2011-04-01
All 18 bound pure vibrational levels of the HD molecule have been calculated within the framework that does not assume the Born-Oppenheimer (BO) approximation. The nonrelativistic energies of the states have been corrected for the relativistic effects of the order of α2 (where α is the fine structure constant), calculated using the perturbation theory with the nonrelativistic non-BO wave functions being the zero-order approximation. The calculations were performed by expanding the non-BO wave functions in terms of one-center explicitly correlated Gaussian functions multiplied by even powers of the internuclear distance and by performing extensive optimization of the Gaussian nonlinear parameters. Up to 10 000 basis functions were used for each state.
One-Step Direct Return Method For Mohr-Coulomb Plasticity
DEFF Research Database (Denmark)
Clausen, Johan; Damkilde, Lars; Andersen, Lars
2004-01-01
A new return method for the Mohr-Coulomb yield criteria is presented. The idea is to transform the problem into the principal direction and thereby achieve very simple formulas for calculating the elastic return stresses.......A new return method for the Mohr-Coulomb yield criteria is presented. The idea is to transform the problem into the principal direction and thereby achieve very simple formulas for calculating the elastic return stresses....
Scattering of {sup 6}He at energies around the Coulomb barrier
Energy Technology Data Exchange (ETDEWEB)
Sanchez-BenItez, A M [Departamento de Fisica Aplicada, Universidad de Huelva, E-21071 Huelva (Spain); Escrig, D [Instituto de Estructura de la Materia, CSIC, E-28006 Madrid (Spain); Alvarez, M A G [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, E-41080 Sevilla (Spain)] [and others
2005-10-01
We have measured elastic cross sections of the scattering of {sup 6}He at E{sub Lab} = 14, 16, 17, 18 and 22 MeV on {sup 208}Pb in the angular ranges of 20 deg. - 64 deg. and 135 deg. - 170 deg. A significant amount of {sup 4}He events is found at energies well below the Coulomb barrier, that becomes dominant above it. Optical model calculations have been performed including a dynamic polarization potential. Very large imaginary diffuseness parameter is needed in order to describe the experimental distributions.
Analysis of Spent Nuclear Fuel Imaging Using Multiple Coulomb Scattering of Cosmic Muons
Chatzidakis, Stylianos; Choi, Chan K.; Tsoukalas, Lefteri H.
2016-12-01
Cosmic ray muons passing through matter lose energy from inelastic collisions with electrons and are deflected from nuclei due to multiple Coulomb scattering. The strong dependence of scattering on atomic number Z and the recent developments on position sensitive muon detectors indicate that multiple Coulomb scattering could be an excellent candidate for spent nuclear fuel imaging. Muons present significant advantages over existing monitoring and imaging techniques and can play a central role in monitoring nuclear waste and spent nuclear fuel stored in dense well shielded containers. The main purpose of this paper is to investigate the applicability of multiple Coulomb scattering for imaging of spent nuclear fuel dry casks stored within vertical and horizontal commercial storage dry casks. Calculations of muon scattering were performed for various scenarios, including vertical and horizontal fully loaded dry casks, half loaded dry casks, dry casks with one row of fuel assemblies missing, dry casks with one fuel assembly missing and empty dry casks. Various detector sizes (1.2 m ×1.2 m, 2.4 m ×2.4 m and 3.6 m ×3.6 m) and number of muons (105, 5 · 105, 106 and 107) were used to assess the effect on image resolution. The Point-of-Closest-Approach (PoCA) algorithm was used for the reconstruction of the stored contents. The results demonstrate that multiple Coulomb scattering can be used to successfully reconstruct the dry cask contents and allow identification of all scenarios with the exception of one fuel assembly missing. In this case, an indication exists that a fuel assembly is not present; however, the resolution of the imaging algorithm was not enough to identify exact location.
Ultrafast dynamics of Coulomb correlated excitons in GaAs quantum wells
Energy Technology Data Exchange (ETDEWEB)
Mycek, M.A. [Univ. of California, Berkeley, CA (United States). Dept. of Physics]|[Lawrence Berkeley National Lab., CA (United States). Materials Sciences Div.
1995-12-01
The author measures the transient nonlinear optical response of room temperature excitons in gallium arsenide quantum wells via multi-wave mixing experiments. The dynamics of the resonantly excited excitons is directly reflected by the ultrafast decay of the induced nonlinear polarization, which radiates the detected multi-wave mixing signal. She characterizes this ultrafast coherent emission in both amplitude and phase, using time- and frequency-domain measurement techniques, to better understand the role of Coulomb correlation in these systems. To interpret the experimental results, the nonlinear optical response of a dense medium is calculated using a model including Coulomb interaction. She contributes three new elements to previous theoretical and experimental studies of these systems. First, surpassing traditional time-integrated measurements, she temporally resolves the amplitude of the ultrafast coherent emission. Second, in addition to measuring the third-order four-wave mixing signal, she also investigates the fifth-order six-wave mixing response. Third, she characterizes the ultrafast phase dynamics of the nonlinear emission using interferometric techniques with an unprecedented resolution of approximately 140 attoseconds. The author finds that effects arising from Coulomb correlation dominate the nonlinear optical response when the density of excitons falls below 3 {times} 10{sup 11} cm{sup {minus}2}, the saturation density. These signatures of Coulomb correlation are investigated for increasing excitation density to gradually screen the interactions and test the validity of the model for dense media. The results are found to be qualitatively consistent with both the predictions of the model and with numerical solutions to the semiconductor Bloch equations. Importantly, the results also indicate current experimental and theoretical limitations, which should be addressed in future research.
Energy Technology Data Exchange (ETDEWEB)
Mohr, H. [Department of Physics, University of Surrey, Guildford, Surrey, GU2 5XH (United Kingdom)
1996-12-01
Electron beam induced current (EBIC) microscopy is a very powerful technique for revealing the electrical activity of defects in semiconductors. Gettering of impurities at defects has been observed previously after certain sample heat treatments, which resulted in altered contrast patterns and line scan profiles. Getter effects have been included in a numerical or analytical contrast simulation which employ the Monte Carlo method for generating the carrier distribution. We compare the findings with an observed white contrast at misfit dislocations in EBIC micrographs. {copyright} {ital 1996 American Institute of Physics.}
Thermal decay of Coulomb blockade oscillations
Idrisov, Edvin G.; Levkivskyi, Ivan P.; Sukhorukov, Eugene V.
2017-10-01
We study transport properties and the charge quantization phenomenon in a small metallic island connected to the leads through two quantum point contacts (QPCs). The linear conductance is calculated perturbatively with respect to weak tunneling and weak backscattering at QPCs as a function of the temperature T and gate voltage. The conductance shows Coulomb blockade (CB) oscillations as a function of the gate voltage that decay with the temperature as a result of thermally activated fluctuations of the charge in the island. The regimes of quantum T ≪EC and thermal T ≫EC fluctuations are considered, where EC is the charging energy of an isolated island. Our predictions for CB oscillations in the quantum regime coincide with previous findings by Furusaki and Matveev [Phys. Rev. B 52, 16676 (1995), 10.1103/PhysRevB.52.16676]. In the thermal regime the visibility of Coulomb blockade oscillations decays with the temperature as √{T /EC }exp(-π2T /EC) , where the exponential dependence originates from the thermal averaging over the instant charge fluctuations, while the prefactor has a quantum origin. This dependence does not depend on the strength of couplings to the leads. The differential capacitance, calculated in the case of a single tunnel junction, shows the same exponential decay, however the prefactor is linear in the temperature. This difference can be attributed to the nonlocality of the quantum effects. Our results agree with the recent experiment [Nature (London) 536, 58 (2016), 10.1038/nature19072] in the whole range of the parameter T /EC .
Lyutorovich, N.; Speth, J.; Avdeenkov, A.; Grümmer, F.; Kamerdzhiev, S.; Krewald, S.; Tselyaev, V. I.
2008-09-01
The Green’s function method in the Quasiparticle Time Blocking Approximation is applied to nuclear excitations in 132Sn and 208Pb. The calculations are performed self-consistently using a Skyrme interaction. The method combines the conventional RPA with an exact single-particle continuum treatment and considers in a consistent way the particle-phonon coupling. We reproduce not only the experimental values of low-and high-lying collective states but we also obtain fair agreement with the data of non-collective low-lying states that are strongly influenced by the particle-phonon coupling.
New insights into the application of the Coulomb model in real-time
Catalli, Flaminia; Chan, Chung-Han
2012-02-01
The Coulomb model for stress change estimation is considered one of the most powerful physics-based forecasting tools, even though its calculations are affected by uncertainties due to the large number of a priori assumptions needed. The aim of this paper is to suggest a straightforward and reliable strategy to apply the Coulomb model for real-time forecasting. This is done by avoiding all dispensable assumptions, thus reducing the corresponding uncertainties. We demonstrate that the depth at which calculations are made is a parameter of utmost importance and apply the Coulomb model to three sequences in different tectonic regimes: Umbria-Marche (normal), Landers (strike-slip), and Chi-Chi (thrust). In each case the results confirm that when applying the Coulomb model: (i) the depth of calculation plays a fundamental role; (ii) depth uncertainties are not negligible; (iii) the best forecast at a given location is obtained by selecting the maximum stress change over the whole seismogenic depth range.
Effect of Coulombic friction on spatial displacement statistics.
Menzel, Andreas M; Goldenfeld, Nigel
2011-07-01
The phenomenon of Coulombic friction enters the stochastic description of dry friction between two solids and the statistic characterization of vibrating granular media. Here we analyze the corresponding Fokker-Planck equation including both velocity and spatial components, exhibiting a formal connection to a quantum mechanical harmonic oscillator in the presence of a delta potential. Numerical solutions for the resulting spatial displacement statistics show a crossover from exponential to Gaussian displacement statistics. We identify a transient intermediate regime that exhibits multiscaling properties arising from the contribution of Coulombic friction. The possible role of these effects during observations in diffusion experiments is briefly discussed.
PREFACE: Strongly Coupled Coulomb Systems Strongly Coupled Coulomb Systems
Neilson, David; Senatore, Gaetano
2009-05-01
This special issue contains papers presented at the International Conference on Strongly Coupled Coulomb Systems (SCCS), held from 29 July-2 August 2008 at the University of Camerino. Camerino is an ancient hill-top town located in the Apennine mountains of Italy, 200 kilometres northeast of Rome, with a university dating back to 1336. The Camerino conference was the 11th in a series which started in 1977: 1977: Orleans-la-Source, France, as a NATO Advanced Study Institute on Strongly Coupled Plasmas (hosted by Marc Feix and Gabor J Kalman) 1982: Les Houches, France (hosted by Marc Baus and Jean-Pierre Hansen) 1986: Santa Cruz, California, USA (hosted by Forrest J Rogers and Hugh E DeWitt) 1989: Tokyo, Japan (hosted by Setsuo Ichimaru) 1992: Rochester, New York, USA (hosted by Hugh M Van Horn and Setsuo Ichimaru) 1995: Binz, Germany (hosted by Wolf Dietrich Kraeft and Manfred Schlanges) 1997: Boston, Massachusetts, USA (hosted by Gabor J Kalman) 1999: St Malo, France (hosted by Claude Deutsch and Bernard Jancovici) 2002: Santa Fe, New Mexico, USA (hosted by John F Benage and Michael S Murillo) 2005: Moscow, Russia (hosted by Vladimir E Fortov and Vladimir Vorob'ev). The name of the series was changed in 1996 from Strongly Coupled Plasmas to Strongly Coupled Coulomb Systems to reflect a wider range of topics. 'Strongly Coupled Coulomb Systems' encompasses diverse many-body systems and physical conditions. The purpose of the conferences is to provide a regular international forum for the presentation and discussion of research achievements and ideas relating to a variety of plasma, liquid and condensed matter systems that are dominated by strong Coulomb interactions between their constituents. Each meeting has seen an evolution of topics and emphases that have followed new discoveries and new techniques. The field has continued to see new experimental tools and access to new strongly coupled conditions, most recently in the areas of warm matter, dusty plasmas
Liu, Wei; Tan, Zhenyu; Zhang, Liming; Champion, Christophe
2017-03-01
In this work, direct DNA damage induced by low-energy electrons (sub-keV) is simulated using a Monte Carlo method. The characteristics of the present simulation are to consider the new mechanism of DNA damage due to dissociative electron attachment (DEA) and to allow determining damage to specific bases (i.e., adenine, thymine, guanine, or cytosine). The electron track structure in liquid water is generated, based on the dielectric response model for describing electron inelastic scattering and on a free-parameter theoretical model and the NIST database for calculating electron elastic scattering. Ionization cross sections of DNA bases are used to generate base radicals, and available DEA cross sections of DNA components are applied for determining DNA-strand breaks and base damage induced by sub-ionization electrons. The electron elastic scattering from DNA components is simulated using cross sections from different theoretical calculations. The resulting yields of various strand breaks and base damage in cellular environment are given. Especially, the contributions of sub-ionization electrons to various strand breaks and base damage are quantitatively presented, and the correlation between complex clustered DNA damage and the corresponding damaged bases is explored. This work shows that the contribution of sub-ionization electrons to strand breaks is substantial, up to about 40-70%, and this contribution is mainly focused on single-strand break. In addition, the base damage induced by sub-ionization electrons contributes to about 20-40% of the total base damage, and there is an evident correlation between single-strand break and damaged base pair A-T.
Planar density of vacuum charge induced by a supercritical Coulomb potential
Energy Technology Data Exchange (ETDEWEB)
Khalilov, V.R., E-mail: khalilov@phys.msu.ru; Mamsurov, I.V.
2017-06-10
Analytical expressions for the planar density of an induced vacuum charge are obtained in a strong Coulomb potential in coordinate space. Treatment is based on a self-adjoint extension approach for constructing of the Green's function of a charged fermion in an external electromagnetic field. Induced vacuum charge density is calculated and analyzed in subcritical and supercritical Coulomb potentials for massless and massive fermions. We argue that the virtual and so-called real vacuum polarizations contribute in an induced vacuum charge in a supercritical Coulomb potential. The behavior of the polarization vacuum charge density is investigated at long and short distances from the Coulomb center. The induced vacuum charge has a screening sign. Screening of a Coulomb impurity in graphene is briefly discussed. The real vacuum polarization charge density that acquires the quantum electrodynamics vacuum in a supercritical Coulomb potential due to the real vacuum polarization is calculated. It is shown that the vacuum charge densities essentially differ in massive and massless cases. We expect that our results can, as a matter of principle, be tested in graphene with a supercritical Coulomb impurity.
Planar density of vacuum charge induced by a supercritical Coulomb potential
Directory of Open Access Journals (Sweden)
V.R. Khalilov
2017-06-01
Full Text Available Analytical expressions for the planar density of an induced vacuum charge are obtained in a strong Coulomb potential in coordinate space. Treatment is based on a self-adjoint extension approach for constructing of the Green's function of a charged fermion in an external electromagnetic field. Induced vacuum charge density is calculated and analyzed in subcritical and supercritical Coulomb potentials for massless and massive fermions. We argue that the virtual and so-called real vacuum polarizations contribute in an induced vacuum charge in a supercritical Coulomb potential. The behavior of the polarization vacuum charge density is investigated at long and short distances from the Coulomb center. The induced vacuum charge has a screening sign. Screening of a Coulomb impurity in graphene is briefly discussed. The real vacuum polarization charge density that acquires the quantum electrodynamics vacuum in a supercritical Coulomb potential due to the real vacuum polarization is calculated. It is shown that the vacuum charge densities essentially differ in massive and massless cases. We expect that our results can, as a matter of principle, be tested in graphene with a supercritical Coulomb impurity.
Fast Electron Repulsion Integrals for Molecular Coulomb Sturmians
DEFF Research Database (Denmark)
Avery, James Emil
2013-01-01
of hyperspherical harmonics. A rudimentary software library has been implemented and preliminary benchmarks indicate very good performance: On average 40 ns, or approximately 80 clock cycles, per electron repulsion integral. This makes molecular Coulomb Sturmians competitive with Gaussian type orbitals in terms......A new method is presented for calculating interelectron repulsion integrals for molecular Coulomb Sturmian basis sets. This makes use of an expansion of densities in terms of 2k-Sturmians, and the interelectron repulsion integrals are then calculated by a method based on the theory...... of speed, and is three to four orders of magnitude faster than methods based on expanding the exponential type orbitals in Gaussians. A full software library will be made available during autumn 2013....
Coulomb displacement energies and isospin-nonconservation for fp-shell nuclei
Ormand, William; Kruse, Michael; Borwn, Alex; Hjorth-Jensen, Morten
2013-10-01
A new isospin nonconserving (INC) interaction for fp-shell nuclei is determined empirically by fitting to experimental Coulomb displacement energies. This interaction is based on the Coulomb interaction as well as charge-asymmetric and charge-dependent components in the nucleon-nucleon sector as found in realistic nucleon interactions such as CD-Bonn and effective field theory at N3LO. The INC components arising from the nucleon-nucleon interaction were determined through a renormalization procedure from a G-matrix calculation as well as many-body perturbation theory. The overall strength of these components is tuned to reproduce experimental b- and c-coefficients of the isosbaric mass multiplet equation. A new feture of this interaction is that where possible calculations were performed using the full fp-shell; made possible with recent advances in shell-model codes and high-performance computing. With this interaction, isospin-mixing effects in the fp-shell are estimated including a new calculation of isospin-mixing corrections for Fermi transitions in the fp-shell. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Lawrence Livermore National Security, LLC.
Coulomb crystallization in classical and quantum systems
Bonitz, Michael
2007-11-01
Coulomb crystallization occurs in one-component plasmas when the average interaction energy exceeds the kinetic energy by about two orders of magnitude. A simple road to reach such strong coupling consists in using external confinement potentials the strength of which controls the density. This has been succsessfully realized with ions in traps and storage rings and also in dusty plasma. Recently a three-dimensional spherical confinement could be created [1] which allows to produce spherical dust crystals containing concentric shells. I will give an overview on our recent results for these ``Yukawa balls'' and compare them to experiments. The shell structure of these systems can be very well explained by using an isotropic statically screened pair interaction. Further, the thermodynamic properties of these systems, such as the radial density distribution are discussed based on an analytical theory [3]. I then will discuss Coulomb crystallization in trapped quantum systems, such as mesoscopic electron and electron hole plasmas in coupled layers [4,5]. These systems show a very rich correlation behavior, including liquid and solid like states and bound states (excitons, biexcitons) and their crystals. On the other hand, also collective quantum and spin effects are observed, including Bose-Einstein condensation and superfluidity of bound electron-hole pairs [4]. Finally, I consider Coulomb crystallization in two-component neutral plasmas in three dimensions. I discuss the necessary conditions for crystals of heavy charges to exist in the presence of a light component which typically is in the Fermi gas or liquid state. It can be shown that their exists a critical ratio of the masses of the species of the order of 80 [5] which is confirmed by Quantum Monte Carlo simulations [6]. Familiar examples are crystals of nuclei in the core of White dwarf stars, but the results also suggest the existence of other crystals, including proton or α-particle crystals in dense matter
Coulomb form factors of odd-A nuclei within an axially deformed relativistic mean-field model
Liu, Jian; Xu, Chang; Wang, Shuo; Ren, Zhongzhou
2017-09-01
Background: The nuclear Coulomb form factor | FC(q) | 2 is a useful tool to study nuclear structure. For spherical nuclei, | FC(q) | 2 can be calculated by combining the spherical relativistic mean-field (RMF) model and the distorted wave Born approximation (DWBA) method. Purpose: In a previous paper, the axially deformed RMF model + DWBA method was successfully applied to study the Coulomb form factors of deformed even-even nuclei. In this paper, we further extend this method to study the Coulomb form factors of deformed odd-A nuclei. Method: First, the charge distributions of odd-A nuclei are calculated with the deformed RMF model and expanded into multipole components. Next, with the multipole moment charge distributions, the Coulomb multipoles C 0 , C 2 , and C 4 are calculated. Finally, by summing over Coulomb multipoles required, the Coulomb form factors of odd-A nuclei can be obtained. Results: For deformed odd-A nuclei, the theoretical Coulomb form factors calculated from the deformed RMF charge densities are in better agreement with the experimental data. For nuclei with J ≥1 , the diffraction minima of Coulomb form factors are much flatter, which is due to the contributions of quadrupole charge distributions. Conclusions: Results indicate that the axially deformed RMF model can give reasonable descriptions for multipole moment charge distributions of odd-A nuclei. The method in this paper can provide a useful guide for future experiments of electron scattering off exotic odd-A nuclei.
Coulomb dissociation of N-20,N-21
Roeder, Marko; Adachi, Tatsuya; Aksyutina, Yulia; Alcantara, Juan; Altstadt, Sebastian; Alvarez-Pol, Hector; Ashwood, Nicholas; Atar, Leyla; Aumann, Thomas; Avdeichikov, Vladimir; Barr, M.; Beceiro, Saul; Bemmerer, Daniel; Benlliure, Jose; Bertulani, Carlos; Boretzky, Konstanze; Borge, Maria J. G.; Burgunder, G.; Caamano, Manuel; Caesar, Christoph; Casarejos, Enrique; Catford, Wilton; Cederkall, Joakim; Chakraborty, S.; Chartier, Marielle; Chulkov, Leonid; Cortina-Gil, Dolores; Crespo, Raquel; Pramanik, Ushasi Datta; Diaz-Fernandez, Paloma; Dillmann, Iris; Elekes, Zoltan; Enders, Joachim; Ershova, Olga; Estrade, A.; Farinon, F.; Fraile, Luis M.; Freer, Martin; Freudenberger, M.; Fynbo, Hans; Galaviz, Daniel; Geissel, Hans; Gernhaeuser, Roman; Goebel, Kathrin; Golubev, Pavel; Diaz, D. Gonzalez; Hagdahl, Julius; Heftrich, Tanja; Heil, Michael; Heine, Marcel; Heinz, Andreas; Henriques, Ana; Holl, Matthias; Ickert, G.; Ignatov, Alexander; Jakobsson, Bo; Johansson, Hakan; Jonson, Bjorn; Kalantar-Nayestanaki, Nasser; Kanungo, Rituparna; Kelic-Heil, Aleksandra; Knoebel, Ronja; Kroell, Thorsten; Kruecken, Reiner; Kurcewicz, J.; Kurz, Nikolaus; Labiche, Marc; Langer, Christoph; Le Bleis, Tudi; Lemmon, Roy; Lepyoshkina, Olga; Lindberg, Simon; Machado, Jorge; Marganiec, Justyna; Mostazo Caro, Magdalena; Movsesyan, Alina; Najafi, Mohammad Ali; Nilsson, Thomas; Nociforo, Chiara; Panin, Valerii; Paschalis, Stefanos; Perea, Angel; Petri, Marina; Pietri, S.; Plag, Ralf; Prochazka, A.; Rahaman, Md. Anisur; Rastrepina, Ganna; Reifarth, Rene; Ribeiro, Guillermo; Ricciardi, M. Valentina; Rigollet, Catherine; Riisager, Karsten; Rossi, Dominic; del Rio Saez, Jose Sanchez; Savran, Deniz; Scheit, Heiko; Simon, Haik; Sorlin, Olivier; Stoica, V.; Streicher, Branislav; Taylor, Jon; Tengblad, Olof; Terashima, Satoru; Thies, Ronja; Togano, Yasuhiro; Uberseder, Ethan; Van de Walle, J.; Velho, Paulo; Volkov, Vasily; Wagner, Andreas; Wamers, Felix; Weick, Helmut; Weigand, Mario; Wheldon, Carl; Wilson, G.; Wimmer, Christine; Winfield, J. S.; Woods, Philip; Yakorev, Dmitry; Zhukov, Mikhail; Zilges, Andreas; Zuber, Kai
2016-01-01
Neutron-rich light nuclei and their reactions play an important role in the creation of chemical elements. Here, data from a Coulomb dissociation experiment on N-20,N-21 are reported. Relativistic N-20,N-21 ions impinged on a lead target and the Coulomb dissociation cross section was determined in a
Intersite Coulomb interaction and Heisenberg exchange
Eder, R; van den Brink, J.; Sawatzky, G.A
1996-01-01
Based on exact diagonalization results for small clusters we discuss the effect of intersite Coulomb repulsion in Mott-Hubbard or charge transfers insulators. Whereas the exchange constant J for direct exchange is enhanced by intersite Coulomb interaction, that for superexchange is suppressed. The
Energy Technology Data Exchange (ETDEWEB)
Nociforo, C. [Institut fuer Kernchemie, Johannes Gutenberg Universitaet, D-55099 Mainz (Germany)]. E-mail: nociforo@lns.infn.it; Jones, K.L.; Aumann, T.; Datta Pramanik, U.; Emling, H.; Geissel, H.; Hellstroem, M.; Leifels, Y.; Muenzenberg, G.; Suemmerer, K.; Weick, H.; Typel, S. [Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany); Khiem, L.H. [Institut fuer Kernchemie, Johannes Gutenberg Universitaet, D-55099 Mainz (Germany); Adrich, P. [Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany)]|[Instytut Fizyki, Uniwersytet Jagellonski, PL-30-059 Cracow (Poland); Carlson, B.V. [Instituto Tecnologico de Aeronautica, CTA, Sao Jose dos Campos (Brazil); Cortina-Gil, D. [Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany)]|[Universidad de Santiago de Compostela, E-15706 Santiago de Compostela (Spain); Elze, Th.W. [Institut fuer Kernphysik, Johann Wolfgang Goethe Universitaet, D-60486 Frankfurt (Germany); Kratz, J.V. [Institut fuer Kernchemie, Johannes Gutenberg Universitaet, D-55099 Mainz (Germany); Kulessa, R. [Instytut Fizyki, Uniwersytet Jagellonski, PL-30-059 Cracow (Poland); Lange, T. [Institut fuer Kernphysik, Johann Wolfgang Goethe Universitaet, D-60486 Frankfurt (Germany); Lenske, H. [Institut fuer Theoretische, Universitaet Giessen, D-35392 Giessen (Germany); Lubkiewicz, E. [Instytut Fizyki, Uniwersytet Jagellonski, PL-30-059 Cracow (Poland); Palit, R. [Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany)]|[Institut fuer Kernphysik, Johann Wolfgang Goethe Universitaet, D-60486 Frankfurt (Germany); Scheit, H. [Max-Planck Institut fuer Kernphysik, D-69029 Heidelberg (Germany); Simon, H. [Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany)]|[Institut fuer Kernphysik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany); Wajda, E.; Walus, W. [Instytut Fizyki, Uniwersytet Jagellonski, PL-30-059 Cracow (Poland)
2005-01-06
The ground-state structure of the near-drip-line nucleus {sup 23}O has been investigated in a one-neutron Coulomb breakup reaction. Differential cross sections d{sigma}/dE* for electromagnetic excitation of {sup 23}O projectiles (422 MeV/nucleon) incident on a lead target have been obtained from the measurement of the momenta of all breakup products including {gamma} rays. The analysis of the deduced dipole-transition probability into the continuum infers a 2s{sub 1/2}-bar O22(0{sup +}) ground state configuration with a spectroscopic factor of 0.77(10) and thus a ground-state spin I{sup {pi}}(O23)=1/2{sup +}, resolving earlier conflicting experimental findings. Final-state interaction is of significant influence, an effective reduced scattering length for low-energy p{sub 3/2} neutron scattering could be derived from the data.
Powerful Coulomb-drag thermoelectric engine
Daré, A.-M.; Lombardo, P.
2017-09-01
We investigate a thermoelectric nanoengine whose properties are steered by Coulomb interaction. The device whose design decouples charge and energy currents is made up of two interacting quantum dots connected to three different reservoirs. We show that, by tailoring the tunnel couplings, this setup can be made very attractive for energy-harvesting prospects, due to a delivered power that can be of the order of the quantum bound [R. S. Whitney, Phys. Rev. Lett. 112, 130601 (2014), 10.1103/PhysRevLett.112.130601; Entropy 18, 208 (2016), 10.3390/e18060208], with a concomitant fair efficiency. To unveil its properties beyond the sequential quantum master equation, we apply a nonequilibrium noncrossing approximation in the Keldysh Green's function formalism, and a quantum master equation that includes cotunneling processes. Both approaches are rather qualitatively similar in a large operating regime where sequential tunneling alone fails.
New insights into the application of the Coulomb model in real-time
Flaminia Catalli; C.-H. Chan
2012-01-01
The Coulomb model for stress change estimation is considered one of the most powerful physics-based forecasting tools, even though its calculations are affected by uncertainties due to the large number of a priori assumptions needed. The aim of this paper is to suggest a straightforward and reliable strategy to apply the Coulomb model for real-time forecasting. This is done by avoiding all dispensable assumptions, thus reducing the corresponding uncertainties. We demonstrate that the depth at...
Coulomb excitation of {sup 48}K
Energy Technology Data Exchange (ETDEWEB)
Siebeck, Burkhard; Blazhev, Andrey; Geibel, Kerstin; Hess, Herbert; Reiter, Peter; Seidlitz, Michael; Schneiders, David; Steinbach, Tim; Warr, Nigel [IKP, Universitaet zu Koeln (Germany); Bauer, Christopher [IKP, TU Darmstadt (Germany); Witte, Hilde de [KU Leuven (Belgium); Klintefjord, Malin [University of Oslo (Norway); Pakarinen, Janne [University of Jyvaeskylae (Finland); Rapisarda, Elisa [KU Leuven (Belgium); CERN, Genf (Switzerland); Scheck, Marcus [University of the West of Scotland, Paisley (United Kingdom); Voulot, Didier; Wenander, Frederik [CERN, Genf (Switzerland)
2016-07-01
Potassium isotopes in the direct vicinity of doubly-magic nuclei are of great interest and subject of recent shell model calculations. These show that the ground states of most K isotopes are dominated by a π0p0h configuration, while {sup 47}K and {sup 49}K have a major π2p2h contribution. However, the situation is not clear for the odd-odd isotope {sup 48}K, which shows a mixture between 0p0h and 2p2h. In order to study the coupling between the νp{sub 3/2}-shell and the πs{sub 1/2}-, πd{sub 3/2}-shells, transition matrix elements are deduced from a Coulomb excitation experiment performed with MINIBALL at REX-ISOLDE. A {sup 104}Pd target was irradiated by a radioactive {sup 48}K beam. γ rays of both target and projectile deexcitation have been observed. Those yields, together with available spectroscopic data, allow the detemination of transition matrix elements with GOSIA2. The new findings are compared to shell model calculations.
Energy Technology Data Exchange (ETDEWEB)
Stefanini, A.M.; Corradi, L.; Ackermann, D.; Facco, A.; Gramegna, F.; Moreno, H.; Mueller, L.; Napoli, D.R.; Prete, G.F.; Spolaore, P. (Ist. Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro); Beghini, S.; Fabris, D.; Montagnoli, G.; Nebbia, G.; Ruiz, J.A.; Segato, G.F.; Signorini, C.; Viesti, G. (Padua Univ. (Italy). Dipt. di Fisica Ist. Nazionale di Fisica Nucleare, Padua (Italy))
1992-10-19
Fusion cross sections and mean angular momenta have been measured for [sup 64]Ni + [sup 92,96]Zr around the Coulomb barrier. The results are presented and systematically compared with the predictions of a schematic coupled-channel model, demonstrating the need of more refined calculations including higher-order coupling effects, and/or other degrees of freedom, beyond the usual inelastic and quasi-elastic transfer channels. (orig.).
Bubin, Sergiy; Stanke, Monika; Molski, Marcin; Adamowicz, Ludwik
2010-07-01
In this work we report very accurate variational calculations of the two lowest vibrational states of the D2 and T2 molecules within the framework that does not assume the Born-Oppenheimer approximation. The non-relativistic energies of the states obtained in the non-BO calculations are corrected for the relativistic effects of the order of α2 calculated as expectation values of the operators representing these effects. The v=0→1 transition energy of D2 obtained in the calculations is compared with the transition frequency obtained from the experimental spectra. The comparison shows the need to include corrections higher than second-order in α to further improve the agreement between the theory and the experiment.
Large ion Coulomb crystals: A near-ideal medium for coupling optical cavity modes to matter
DEFF Research Database (Denmark)
Dantan, Aurélien; Albert, Magnus; Marler, Joan
2009-01-01
We present an investigation of the coherent coupling of various transverse field modes of an optical cavity to ion Coulomb crystals. The obtained experimental results, which include the demonstration of identical collective coupling rates for different transverse modes of a cavity field to ions...... in the same large Coulomb crystal, are in excellent agreement with theoretical predictions. The results furthermore suggest that Coulomb crystals in the future may serve as near-ideal media for high-fidelity multimode quantum information processing and communication purposes, including the generation...... and storage of single-photon qubits encoded in different transverse modes....
Limpanuparb, Taweetham; Milthorpe, Josh; Rendell, Alistair P
2014-10-30
Use of the modern parallel programming language X10 for computing long-range Coulomb and exchange interactions is presented. By using X10, a partitioned global address space language with support for task parallelism and the explicit representation of data locality, the resolution of the Ewald operator can be parallelized in a straightforward manner including use of both intranode and internode parallelism. We evaluate four different schemes for dynamic load balancing of integral calculation using X10's work stealing runtime, and report performance results for long-range HF energy calculation of large molecule/high quality basis running on up to 1024 cores of a high performance cluster machine. Copyright © 2014 Wiley Periodicals, Inc.
Optical conductivity of layered ruthenates. The role of spin-orbit coupling and Coulomb anisotropy
Energy Technology Data Exchange (ETDEWEB)
Sarvestani, Esmaeel; Zhang, Guoren; Gorelov, Evgeny; Pavarini, Eva [Institute for Advanced Simulation, Forschungszentrum Juelich (Germany)
2016-07-01
We use the combination of density functional theory and dynamical mean-field theory (LDA+DMFT) to calculate the optical conductivity of the layered ruthenates Sr{sub 2}RuO{sub 4} and Sr{sub 3}Ru{sub 2}O{sub 7}. The calculations are performed via linear response theory and Kubo's formalism. For Sr{sub 2}RuO{sub 4} two sets of interaction parameters, (U,J)=(2.3,0.4)eV and (3.1,0.7)eV, both commonly employed for ruthenates, are used. We show that including the spin-orbit coupling improves the agreement with experimental data. Finally, we analyze the effects of low-symmetry Coulomb interaction.
Seidlitz, M; Reiter, P; Bildstein, V; Blazhev, A; Bree, N; Bruyneel, B; Cederkall, J; Clement, E; Davinson, T; van Duppen, P; Ekstrom, A; Finke, F; Fraile, L M; Geibel, K; Gernhauser, R; Hess, H; Holler, A; Huyse, M; Ivanov, O; Jolie, J; Kalkuhler, M; Kotthaus, T; Krucken, R; Lutter, R; Piselli, E; Scheit, H; Stefanescu, I; van de Walle, J; Voulot, D; Warr, N; Wenander, F; Wiens, A
2011-01-01
The ground state properties of ^3^1Mg indicate a change of nuclear shape at N=19 with a deformed J^@p=1/2^+ intruder state as a ground state, implying that ^3^1Mg is part of the ''island of inversion''. The collective properties of excited states were the subject of a Coulomb excitation experiment at REX-ISOLDE, CERN, employing a radioactive ^3^1Mg beam. De-excitation @c-rays were detected by the MINIBALL @c-spectrometer in coincidence with scattered particles in a segmented Si-detector. The level scheme of ^3^1Mg was extended. Spin and parity assignment of the 945 keV state yielded 5/2^+ and its de-excitation is dominated by a strong collective M1 transition. Comparison of the transition probabilities of ^3^0^,^3^1^,^3^2Mg establishes that for th e N=19 magnesium isotope not only the ground state but also excited states are largely dominated by a deformed pf intruder configuration.
Diriken, J; Balabanski, D; Blasi, N; Blazhev, A; Bree, N; Cederkäll, J; Cocolios, T E; Davinson, T; Eberth, J; Ekström, A; Fedorov, D V; Fedosseev, V N; Fraille, L M; Franchoo, S; Georgiev, G; Gladnishki, K; Huyse, M; Ivanov, O V; Ivanov, V S; Iwanicki, V; Jolie, J; Konstantinopoulos, T; Kröll, Th; Krücken, R; Köster, U; Lagoyannis, A; Bianco, G Lo; Maierbeck, P; March, B A; Napiarkowski, P; Patronis, N; Pauwels, D; Reiter, P; Seliverstov, M; Sletten, G; Van de Walle, J; Van Duppen, P; Voulot, D; Walters, W B; Warr, N; Wenander, F; Wrzosek, K
2010-01-01
The B(E2; Ii ! If ) values for transitions in 71Ga and 73Ga were deduced from a Coulomb excitation experiment at the safe energy of 2.95 MeV/nucleon using post-accelerated beams of 71,73Ga at the REX-ISOLDE on-line isotope mass separator facility. The emitted gamma rays were detected by the MINIBALL-detector array and B(E2; Ii->If ) values were obtained from the yields normalized to the known strength of the 2+ -> 0+ transition in the 120Sn target. The comparison of these new results with the data of less neutron-rich gallium isotopes shows a shift of the E2 collectivity towards lower excitation energy when adding neutrons beyond N = 40. This supports conclusions from previous studies of the gallium isotopes which indicated a structural change in this isotopical chain between N = 40 and N = 42. Combined with recent measurements from collinear laser spectroscopy showing a 1/2- spin and parity for the ground state, the extracted results revealed evidence for a 1/2-; 3/2- doublet near the ground state in 73 31Ga...
Shakeoff Ionization near the Coulomb Barrier Energy
Sharma, Prashant; Nandi, T.
2017-11-01
We measure the projectile K x-ray spectra as a function of the beam energies around the Coulomb barrier in different collision systems. The energy is scanned in small steps around the barrier aiming to explore the nuclear effects on the elastically scattered projectile ions. The variation of the projectile x-ray energy with the ion-beam energies exhibits an unusual increase in between the interaction barrier and fusion barrier energies. This additional contribution to the projectile ionization can be attributed to the shakeoff of outer-shell electrons of the projectile ions due to the sudden nuclear recoil (˜10-21 sec ) caused by the attractive nuclear potential, which gets switched on near the interaction barrier energy. In the sudden approximation limit, the theoretical shakeoff probability calculation due to the nuclear recoil explains the observed data well. In addition to its fundamental interest, such processes can play a significant role in dark matter detection through the possible mechanism of x-ray emissions, where the weakly interacting massive particle-nucleus elastic scattering can lead to the nuclear-recoil-induced inner-shell vacancy creations. Furthermore, the present work may provide new prospects for atomic physics research at barrier energies as well as provide a novel technique to perform barrier distribution studies for two-body systems.
Mielke, Steven L; Dinpajooh, Mohammadhasan; Siepmann, J Ilja; Truhlar, Donald G
2013-01-07
We present a procedure to calculate ensemble averages, thermodynamic derivatives, and coordinate distributions by effective classical potential methods. In particular, we consider the displaced-points path integral (DPPI) method, which yields exact quantal partition functions and ensemble averages for a harmonic potential and approximate quantal ones for general potentials, and we discuss the implementation of the new procedure in two Monte Carlo simulation codes, one that uses uncorrelated samples to calculate absolute free energies, and another that employs Metropolis sampling to calculate relative free energies. The results of the new DPPI method are compared to those from accurate path integral calculations as well as to results of two other effective classical potential schemes for the case of an isolated water molecule. In addition to the partition function, we consider the heat capacity and expectation values of the energy, the potential energy, the bond angle, and the OH distance. We also consider coordinate distributions. The DPPI scheme performs best among the three effective potential schemes considered and achieves very good accuracy for all of the properties considered. A key advantage of the effective potential schemes is that they display much lower statistical sampling variances than those for accurate path integral calculations. The method presented here shows great promise for including quantum effects in calculations on large systems.
Prospective testing of Coulomb short-term earthquake forecasts
Jackson, D. D.; Kagan, Y. Y.; Schorlemmer, D.; Zechar, J. D.; Wang, Q.; Wong, K.
2009-12-01
Earthquake induced Coulomb stresses, whether static or dynamic, suddenly change the probability of future earthquakes. Models to estimate stress and the resulting seismicity changes could help to illuminate earthquake physics and guide appropriate precautionary response. But do these models have improved forecasting power compared to empirical statistical models? The best answer lies in prospective testing in which a fully specified model, with no subsequent parameter adjustments, is evaluated against future earthquakes. The Center of Study of Earthquake Predictability (CSEP) facilitates such prospective testing of earthquake forecasts, including several short term forecasts. Formulating Coulomb stress models for formal testing involves several practical problems, mostly shared with other short-term models. First, earthquake probabilities must be calculated after each “perpetrator” earthquake but before the triggered earthquakes, or “victims”. The time interval between a perpetrator and its victims may be very short, as characterized by the Omori law for aftershocks. CSEP evaluates short term models daily, and allows daily updates of the models. However, lots can happen in a day. An alternative is to test and update models on the occurrence of each earthquake over a certain magnitude. To make such updates rapidly enough and to qualify as prospective, earthquake focal mechanisms, slip distributions, stress patterns, and earthquake probabilities would have to be made by computer without human intervention. This scheme would be more appropriate for evaluating scientific ideas, but it may be less useful for practical applications than daily updates. Second, triggered earthquakes are imperfectly recorded following larger events because their seismic waves are buried in the coda of the earlier event. To solve this problem, testing methods need to allow for “censoring” of early aftershock data, and a quantitative model for detection threshold as a function of
Energy Technology Data Exchange (ETDEWEB)
Lee, Y.S.
1977-11-01
The effects of the 4f shell of electrons and the relativity of valence electrons are compared. The effect of 4f shell (lanthanide contraction) is estimated from the numerical Hartree-Fock (HF) calculations of pseudo-atoms corresponding to Hf, Re, Au, Hg, Tl, Pb and Bi without 4f electrons and with atomic numbers reduced by 14. The relativistic effect estimated from the numerical Dirac-Hartree-Fock (DHF) calculations of those atoms is comparable in the magnitude with that of the 4f shell of electrons. Both are larger for 6s than for 5d or 6p electrons. The various relativistic effects on valence electrons are discussed in detail to determine the proper level of the approximation for the valence electron calculations of systems with heavy elements. An effective core potential system has been developed for heavy atoms in which relativistic effects are included in the effective potentials.
Coulomb-Driven Relativistic Electron Beam Compression
Lu, Chao; Jiang, Tao; Liu, Shengguang; Wang, Rui; Zhao, Lingrong; Zhu, Pengfei; Xiang, Dao; Zhang, Jie
2018-01-01
Coulomb interaction between charged particles is a well-known phenomenon in many areas of research. In general, the Coulomb repulsion force broadens the pulse width of an electron bunch and limits the temporal resolution of many scientific facilities such as ultrafast electron diffraction and x-ray free-electron lasers. Here we demonstrate a scheme that actually makes use of the Coulomb force to compress a relativistic electron beam. Furthermore, we show that the Coulomb-driven bunch compression process does not introduce additional timing jitter, which is in sharp contrast to the conventional radio-frequency buncher technique. Our work not only leads to enhanced temporal resolution in electron-beam-based ultrafast instruments that may provide new opportunities in probing material systems far from equilibrium, but also opens a promising direction for advanced beam manipulation through self-field interactions.
Coulomb flux tube on the lattice
Chung, Kristian; Greensite, Jeff
2017-08-01
In Coulomb gauge a longitudinal electric field is generated instantaneously with the creation of a static quark-antiquark pair. The field due to the quarks is a sum of two contributions, one from the quark and one from the antiquark, and there is no obvious reason that this sum should fall off exponentially with distance from the sources. We show here, however, from numerical simulations in pure SU(2) lattice gauge theory, that the color Coulomb electric field does in fact fall off exponentially with transverse distance away from a line joining static quark-antiquark sources, indicating the existence of a color Coulomb flux tube, and the absence of long-range Coulomb dipole fields.
Coulomb's law in maximally symmetric spaces
Vakili, B.; Gorji, M. A.
2012-01-01
We study the modifications to the Coulomb's law when the background geometry is a $n$-dimensional maximally symmetric space, by using of the $n$-dimensional version of the Gauss' theorem. It is shown that some extra terms are added to the usual expression of the Coulomb electric field due to the curvature of the background space. Also, we consider the problem of existence of magnetic monopoles in such spaces and present analytical expressions for the corresponding magnetic fields and vector p...
Coulomb correction to elastic. alpha. -. alpha. scattering
Energy Technology Data Exchange (ETDEWEB)
Bera, P.K.; Jana, A.K.; Haque, N.; Talukdar, B. (Department of Physics, Visva-Bharati University, Santiniketan-731235, West Bengal, India (IN))
1991-02-01
The elastic {alpha}-{alpha} scattering is treated within the framework of a generalized phase-function method (GPFM). This generalization consists in absorbing the effect of Coulomb interaction in the comparison functions for developing the phase equation. Based on values of scattering phase shifts computed by the present method, it is concluded that the GPFM provides an uncomplicated approach to rigorous Coulomb correction in the {alpha}-{alpha} scattering.
Cavity QED experiments with ion Coulomb crystals
DEFF Research Database (Denmark)
Herskind, Peter Fønss; Dantan, Aurélien; Marler, Joan
2009-01-01
Cavity QED experimental results demonstrating collective strong coupling between ensembles of atomic ions cooled into Coulomb crystals and optical cavity fields have been achieved. Collective Zeeman coherence times of milliseconds have furthermore been obtained.......Cavity QED experimental results demonstrating collective strong coupling between ensembles of atomic ions cooled into Coulomb crystals and optical cavity fields have been achieved. Collective Zeeman coherence times of milliseconds have furthermore been obtained....
NNLL soft and Coulomb resummation for squark and gluino production at the LHC
Energy Technology Data Exchange (ETDEWEB)
Beneke, M. [Physik Department T31, Technische Universität München,James-Franck-Straße 1, D-85748 Garching (Germany); Piclum, J. [Theoretische Physik 1, Naturwissenschaftlich-Technische Fakultät, Universität Siegen,Walter-Flex-Straße 3, D-57068 Siegen (Germany); Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics,University of Bern, Sidlerstrasse 5, CH-3012 Bern (Switzerland); Schwinn, C. [Institut für Theoretische Teilchenphysik und Kosmologie, RWTH Aachen University,Sommerfeldstraße 16, D-52056 Aachen (Germany); Wever, C. [Institute of Nuclear Physics, NCSR “Demokritos' ,Patriarchou Gregoriou E. & Neapoleos street 27, GR 15310 Agia Paraskevi (Greece); Institute for Theoretical Particle Physics (TTP), Karlsruhe Institute of Technology,Engesserstraße 7, D-76128 Karlsruhe (Germany); Institute for Nuclear Physics (IKP), Karlsruhe Institute of Technology,Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)
2016-10-11
We present predictions for the total cross sections for pair production of squarks and gluinos at the LHC including a combined NNLL resummation of soft and Coulomb gluon effects. We derive all terms in the NNLO cross section that are enhanced near the production threshold, which include contributions from spin-dependent potentials and so-called annihilation corrections. The NNLL corrections at √s=13 TeV range from up to 20% for squark-squark production to 90% for gluino pair production relative to the NLO results and reduce the theoretical uncertainties of the perturbative calculation to the 10% level. Grid files with our numerical results are publicly available http://users.ph.tum.de/t31software/SUSYNNLL/.
Simulations of Coulomb systems confined by polarizable surfaces using periodic Green functions
dos Santos, Alexandre P.; Girotto, Matheus; Levin, Yan
2017-11-01
We present an efficient approach for simulating Coulomb systems confined by planar polarizable surfaces. The method is based on the solution of the Poisson equation using periodic Green functions. It is shown that the electrostatic energy arising from the surface polarization can be decoupled from the energy due to the direct Coulomb interaction between the ions. This allows us to combine an efficient Ewald summation method, or any other fast method for summing over the replicas, with the polarization contribution calculated using Green function techniques. We apply the method to calculate density profiles of ions confined between the charged dielectric and metal surfaces.
Femtosecond Studies Of Coulomb Explosion Utilizing Covariance Mapping
Card, D A
2000-01-01
The studies presented herein elucidate details of the Coulomb explosion event initiated through the interaction of molecular clusters with an intense femtosecond laser beam (≥1 PW/cm2). Clusters studied include ammonia, titanium-hydrocarbon, pyridine, and 7-azaindole. Covariance analysis is presented as a general technique to study the dynamical processes in clusters and to discern whether the fragmentation channels are competitive. Positive covariance determinations identify concerted processes such as the concomitant explosion of protonated cluster ions of asymmetrical size. Anti- covariance mapping is exploited to distinguish competitive reaction channels such as the production of highly charged nitrogen atoms formed at the expense of the protonated members of a cluster ion ensemble. This technique is exemplified in each cluster system studied. Kinetic energy analyses, from experiment and simulation, are presented to fully understand the Coulomb explosion event. A cutoff study strongly suggests that...
Triaxiality near the 110Ru ground state from Coulomb excitation
Directory of Open Access Journals (Sweden)
D.T. Doherty
2017-03-01
Full Text Available A multi-step Coulomb excitation measurement with the GRETINA and CHICO2 detector arrays was carried out with a 430-MeV beam of the neutron-rich 110Ru (t1/2=12 s isotope produced at the CARIBU facility. This represents the first successful measurement following the post-acceleration of an unstable isotope of a refractory element. The reduced transition probabilities obtained for levels near the ground state provide strong evidence for a triaxial shape; a conclusion confirmed by comparisons with the results of beyond-mean-field and triaxial rotor model calculations.
Imaging of Acoustic Waves in Piezoelectric Ceramics by Coulomb Coupling
Habib, Anowarul; Shelke, Amit; Pluta, Mieczyslaw; Kundu, Tribikram; Pietsch, Ullrich; Grill, Wolfgang
2012-07-01
The transport properties of bulk and guided acoustic waves travelling in a lead zirconate titanate (PZT) disc, originally manufactured to serve as ultrasonic transducer, have been monitored by scanned Coulomb coupling. The images are recorded by excitation and detection of ultrasound with local electric field probes via piezoelectric coupling. A narrow pulse has been used for excitation. Broadband coupling is achieved since neither mechanical nor electrical resonances are involved. The velocities of the traveling acoustic waves determined from the images are compared with characteristic velocities calculated from material properties listed by the manufacturer of the PZT plate.
Cabria, I.; López, M. J.; Alonso, J. A.
2017-06-01
Simulations of the hydrogen storage capacities of nanoporous carbons require an accurate treatment of the interaction of the hydrogen molecule with the graphite-like surfaces of the carbon pores, which is dominated by the dispersion forces. These interactions are described accurately by high level quantum chemistry methods, like the Coupled Cluster method with single and double excitations and a non-iterative correction for triple excitations (CCSD(T)), but those methods are computationally very expensive for large systems and for massive simulations. Density functional theory (DFT)-based methods that include dispersion interactions at different levels of complexity are less accurate, but computationally less expensive. In order to find DFT-methods that include dispersion interactions to calculate the physisorption of H2 on benzene and graphene, with a reasonable compromise between accuracy and computational cost, CCSD(T), Møller-Plesset second-order perturbation theory method, and several DFT-methods have been used to calculate the interaction energy curves of H2 on benzene and graphene. DFT calculations are compared with CCSD(T) calculations, in the case of H2 on benzene, and with experimental data, in the case of H2 on graphene. Among the DFT methods studied, the B97D, RVV10, and PBE+DCACP methods yield interaction energy curves of H2-benzene in remarkable agreement with the interaction energy curve obtained with the CCSD(T) method. With regards to graphene, the rev-vdW-DF2, PBE-XDM, PBE-D2, and RVV10 methods yield adsorption energies of the lowest level of H2 on graphene, very close to the experimental data.
Coulomb fission of a charged dust cloud in an afterglow plasma
Merlino, Robert; Meyer, John
2015-11-01
A dust cloud of 1 micron diameter silica microspheres was confined in a DC glow discharge dusty plasma in argon at a pressure of 100 mTorr (13 Pa). Laser sheet illumination and a fast video camera (2000 frames/s) was used to record the dynamics of this cloud following the switch-off of the plasma and confining forces. Due to the rapid decay of the plasma, and the substantial residual charge on the particles in the plasma afterglow, the cloud evolved under the mutual Coulomb repulsion forces. A variety of dynamic evolutions were observed with different clouds and under different conditions including, Coulomb explosion and expansion. In one case, the cloud underwent a Coulomb fission process, fragmenting into two clouds. Observations and analysis of this Coulomb fission event will be presented. Work supported by DOE.
Márquez Cruz, Antonio Marcial; Pacheco, Laura C.; Fernández Sanz, Javier
2017-01-01
We present in this work density functional theory calculations of the structural and electronic properties of (PbS)n nanoparticles with n=4-32. Particular care has been taken on the correct description of their electronic structure by using a hybrid functional including the spin-orbit coupling effects. We demonstrate that the bonding in PbS nanoparticles is quite different from bulk PbS as the six Pb-S bonds around a single Pb atom are found to have a different character while in bulk PbS all...
"Safe" Coulomb Excitation of $^{30}$Mg
Niedermaier, O; Bildstein, V; Boie, H; Fitting, J; Von Hahn, R; Köck, F; Lauer, M; Pal, U K; Podlech, H; Repnow, R; Schwalm, D; Alvarez, C; Ames, F; Bollen, G; Emhofer, S; Habs, D; Kester, O; Lutter, R; Rudolph, K; Pasini, M; Thirolf, P G; Wolf, B H; Eberth, J; Gersch, G; Hess, H; Reiter, P; Thelen, O; Warr, N; Weisshaar, D; Aksouh, F; Van den Bergh, P; Van Duppen, P; Huyse, M; Ivanov, O; Mayet, P; Van de Walle, J; Äystö, J; Butler, P A; Cederkäll, J; Delahaye, P; Fynbo, H O U; Fraile-Prieto, L M; Forstner, O; Franchoo, S; Köster, U; Nilsson, T; Oinonen, M; Sieber, T; Wenander, F; Pantea, M; Richter, A; Schrieder, G; Simon, H; Behrens, T; Gernhäuser, R; Kröll, T; Krücken, R; Münch, M M; Davinson, T; Gerl, J; Huber, G; Hurst, A; Iwanicki, J; Jonson, B; Lieb, P; Liljeby, L; Schempp, A; Scherillo, A; Schmidt, P; Walter, G
2005-01-01
We report on the first radioactive beam experiment performed at the recently commissioned REX-ISOLDE facility at CERN in conjunction with the highly efficient $\\gamma$ -spectrometer MINIBALL. Using $^{30}$Mg ions accelerated to an energy of 2.25MeV/u together with a thin $^{nat}$Ni target, Coulomb excitation of the first excited 2+ states of the projectile and target nuclei well below the Coulomb barrier was observed. From the measured relative de-excitation $\\gamma$ -ray yields the B(E2; 0$^{+}_{gs} \\rightarrow 2^{+}_{1}$) value of $^{30}$Mg was determined to be 241(31)$e^{2}$fm$^{4}$. Our result is lower than values obtained at projectile fragmenttion facilities using the intermediate-energy Coulomb excitation method and confirms that the theoretical conjecture that the neutron-rich magnesium isotope $^{30}$Mg lies still outside the "island of inversion".
Effects of large-angle Coulomb collisions on inertial confinement fusion plasmas.
Turrell, A E; Sherlock, M; Rose, S J
2014-06-20
Large-angle Coulomb collisions affect the rates of energy and momentum exchange in a plasma, and it is expected that their effects will be important in many plasmas of current research interest, including in inertial confinement fusion. Their inclusion is a long-standing problem, and the first fully self-consistent method for calculating their effects is presented. This method is applied to "burn" in the hot fuel in inertial confinement fusion capsules and finds that the yield increases due to an increase in the rate of temperature equilibration between electrons and ions which is not predicted by small-angle collision theories. The equilibration rate increases are 50%-100% for number densities of 10(30) m(-3) and temperatures around 1 keV.
Coulomb collisional effects on high energy particles in the presence of driftwave turbulence
Huang, B; Cheng, C Z
2013-01-01
High energy particles' behavior including fusion born alpha particles in an ITER like tokamak in the presence of background driftwave turbulence is investigated by an orbit following calculation. The background turbulence is given by the toroidal driftwave eigenmode combined with a random number generator. The transport level is reduced as the particle energy increase; the widths of the guiding center islands produced by the passing particles are inverse proportional to the square root of parallel velocities. On the other hand, the trapped particles are sensitive to $E \\times B$ drift at the banana tips whose radial displacement is larger for lower energy particles. Coulomb collisional effects are incorporated which modifies the transport process of the trapped high energy particles whose radial excursion resides in limited radial domains without collisions.
Testing the Coulomb stress triggering hypothesis for three recent megathrust earthquakes
Ishibe, Takeo; Ogata, Yosihiko; Tsuruoka, Hiroshi; Satake, Kenji
2017-12-01
We test the static Coulomb stress triggering hypothesis for three recent megathrust earthquakes (the 2004 Sumatra-Andaman earthquake, the 2010 Maule earthquake, and the 2011 Tohoku-Oki earthquake) using focal mechanism solutions for actual earthquakes as receiver faults to calculate Coulomb stress changes. For the 2004 Sumatra-Andaman and 2011 Tohoku-Oki earthquakes, the median values of the Coulomb stress changes for 100 consecutive earthquakes revealed temporal changes from approximately zero before the megathrust earthquake to significant positive values following the mainshock, followed by decay over time. Furthermore, the ratio of the number of positively to negatively stressed receiver faults increased after the megathrust. These results support the triggering hypothesis that the static stress changes imparted by megathrust earthquakes cause seismicity changes. This is in contrast to the results of a previous study that used optimally orientated receiver faults to calculate Coulomb stress changes, and this difference indicates the importance of considering the spatial and temporal heterogeneities of receiver fault distributions. For the 2010 Maule earthquake, however, the results are strongly dependent on fault-slip models. Since most receiver faults are concentrated in the mainshock source region, slip models significantly affect the computed Coulomb stress changes and sometimes cause anomalous stress concentrations along the edge of each sub-fault.
Gür, Mahmut; Muğlu, Halit; Çavuş, M. Serdar; Güder, Aytaç; Sayıner, Hakan S.; Kandemirli, Fatma
2017-04-01
A series of 1,3,4-thiadiazole derivatives including 2- and 3-methoxy cinnamic acids were synthesized, and their structures were elucidated by the UV, IR, 1H NMR, 13C NMR spectroscopies and elemental analysis. The UV and IR calculations of the molecules were performed by using B3LYP, HF and MP2 methods with selected 6-311++G(2d,2p), 6-311++G(3df,3pd) and cc-pvtz basis sets. Dipole moment, polarizability, chemical hardness/softness and electronegativity were also calculated and analyzed. Experimental FT-IR spectra and UV-Vis spectrum of the compounds were compared with theoretical data. Furthermore, antioxidant activities of the compounds were practised via different test methods such as 2,2-diphenyl-1-picryl-hydrazyl (DPPHrad), N,N-dimethyl-p-phenylenediamine (DMPDrad +), and 2,2‧-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTSrad +) scavenging activity assays. When compared with standards (BHA-Butylated hydroxyanisole, RUT-Rutin, and TRO-Trolox), it was observed that especially XIII and XIV which include methoxy groups at the o- and m-positions, respectively, had effective activities.
Coulomb drag in coherent mesoscopic systems
DEFF Research Database (Denmark)
Mortensen, Niels Asger; Flensberg, Karsten; Jauho, Antti-Pekka
2001-01-01
, such as the random matrix theory, or by numerical simulations. We show that Coulomb drag is sensitive to localized states, which usual transport measurements do not probe. For chaotic 2D systems we find a vanishing average drag, with a nonzero variance. Disordered 1D wires show a finite drag, with a large variance...
Coulomb drag in the mesoscopic regime
DEFF Research Database (Denmark)
Mortensen, N.A.; Flensberg, Karsten; Jauho, Antti-Pekka
2002-01-01
We present a theory for Coulomb drag between two mesoscopic systems which expresses the drag in terms of scattering matrices and wave functions. The formalism can be applied to both ballistic and disordered systems and the consequences can be studied either by numerical simulations or analytic...
Local simulation algorithms for Coulombic interactions
Indian Academy of Sciences (India)
Home; Journals; Pramana – Journal of Physics; Volume 64; Issue 6. Local simulation algorithms for Coulombic interactions. L Leverel F Alet J Rottler A C Maggs. Invited Talks:- Topic 7. Soft condensed matter (colloids, polymers, liquid crystals, microemulsions, foams, membranes, etc.) Volume 64 Issue 6 June 2005 pp ...
Interatomic Coulombic decay in helium nanodroplets
DEFF Research Database (Denmark)
Shcherbinin, Mykola; Laforge, Aaron; Sharma, Vandana
2017-01-01
Interatomic Coulombic decay (ICD) is induced in helium nanodroplets by photoexciting the n=2 excited state of He+ using XUV synchrotron radiation. By recording multiple-coincidence electron and ion images we find that ICD occurs in various locations at the droplet surface, inside the surface region...
Coulomb drag in coherent mesoscopic systems
DEFF Research Database (Denmark)
Mortensen, Asger; Flensberg, Karsten; Jauho, Antti-Pekka
2001-01-01
We present a theory for Coulomb drag between two mesoscopic systems. Our formalism expresses the drag in terms of scattering matrices and wave functions, and its range of validity covers both ballistic and disordered systems. The consequences can be worked out either by analytic means...
Coulomb drag in the mesoscopic regime
DEFF Research Database (Denmark)
Mortensen, N. Asger; Flensberg, Karsten; Jauho, Antti-Pekka
2002-01-01
We present a theory for Coulomb drug between two mesoscopic systems which expresses the drag in terms of scattering matrices and wave functions. The formalism can be applied to both ballistic and disordered systems and the consequences can be studied either by numerical simulations or analytic...
DEFF Research Database (Denmark)
Ruban, Andrei; Skriver, Hans Lomholt
2002-01-01
the Madelung potential energy of a random alloy in the single-site, mean-field approximation. The Madelung potential makes density-functional calculations by the conventional single-site, coherent potential approximation practically identical to the more rigorous LSGF supercell results obtained with a single...... of the alloy composition, lattice spacing, and crystal structure. A formalism which allows a consistent treatment of the screened Coulomb interactions within the single-site mean-field approximation is outlined. We also derive the contribution of the screened Coulomb interactions to the S-(2) formalism...
Ground-state configuration of neutron-rich Aluminum isotopes through Coulomb Breakup
Directory of Open Access Journals (Sweden)
Chakraborty S.
2014-03-01
Full Text Available Neutron-rich 34,35Al isotopes have been studied through Coulomb excitation using LAND-FRS setup at GSI, Darmstadt. The method of invariant mass analysis has been used to reconstruct the excitation energy of the nucleus prior to decay. Comparison of experimental CD cross-section with direct breakup model calculation with neutron in p3/2 orbital favours 34Al(g.s⊗νp3/2 as ground state configuration of 35Al. But ground state configuration of 34Al is complicated as evident from γ-ray spectra of 33Al after Coulomb breakup of 34Al.
Ground-state configuration of neutron-rich Aluminum isotopes through Coulomb Breakup
Chakraborty, S.; Datta Pramanik, U.; Aumann, T.; Beceiro, S.; Boretzky, K.; Caesar, C.; Carlson, B. V.; Catford, W. N.; Chatterjee, S.; Chartier, M.; Cortina-Gil, D.; De Angelis, G.; Gonzalez-Diaz, D.; Emling, H.; Diaz Fernandez, P.; Fraile, L. M.; Ershova, O.; Geissel, H.; Heil, M.; Jonson, B.; Kelic, A.; Johansson, H.; Kruecken, R.; Kroll, T.; Kurcewicz, J.; Langer, C.; Le Bleis, T.; Leifels, Y.; Munzenberg, G.; Marganiec, J.; Nociforo, C.; Najafi, A.; Panin, V.; Paschalis, S.; Pietri, S.; Plag, R.; Rahaman, A.; Reifarth, R.; Ricciardi, V.; Rossi, D.; Ray, J.; Simon, H.; Scheidenberger, C.; Typel, S.; Taylor, J.; Togano, Y.; Volkov, V.; Weick, H.; Wagner, A.; Wamers, F.; Weigand, M.; Winfield, J. S.; Yakorev, D.; Zoric, M.
2014-03-01
Neutron-rich 34,35Al isotopes have been studied through Coulomb excitation using LAND-FRS setup at GSI, Darmstadt. The method of invariant mass analysis has been used to reconstruct the excitation energy of the nucleus prior to decay. Comparison of experimental CD cross-section with direct breakup model calculation with neutron in p3/2 orbital favours 34Al(g.s)⊗νp3/2 as ground state configuration of 35Al. But ground state configuration of 34Al is complicated as evident from γ-ray spectra of 33Al after Coulomb breakup of 34Al.
Low rank factorization of the Coulomb integrals for periodic coupled cluster theory
Hummel, Felix; Grüneis, Andreas
2016-01-01
We study the decomposition of the Coulomb integrals of periodic systems into a tensor contraction of six matrices of which only two are distinct. We find that the Coulomb integrals can be well approximated in this form already with small matrices compared to the number of real space grid points. The cost of computing the matrices scales as O(N^4) using a regularized form of the alternating least squares algorithm. The studied factorization of the Coulomb integrals can be exploited to reduce the scaling of the computational cost of expensive tensor contractions appearing in the amplitude equations of coupled cluster methods with respect to system size. We apply the developed methodologies to calculate the adsorption energy of a single water molecule on a hexagonal boron nitride monolayer in a plane wave basis set and periodic boundary conditions.
Low rank factorization of the Coulomb integrals for periodic coupled cluster theory
Hummel, Felix; Tsatsoulis, Theodoros; Grüneis, Andreas
2017-03-01
We study a tensor hypercontraction decomposition of the Coulomb integrals of periodic systems where the integrals are factorized into a contraction of six matrices of which only two are distinct. We find that the Coulomb integrals can be well approximated in this form already with small matrices compared to the number of real space grid points. The cost of computing the matrices scales as O (N4) using a regularized form of the alternating least squares algorithm. The studied factorization of the Coulomb integrals can be exploited to reduce the scaling of the computational cost of expensive tensor contractions appearing in the amplitude equations of coupled cluster methods with respect to system size. We apply the developed methodologies to calculate the adsorption energy of a single water molecule on a hexagonal boron nitride monolayer in a plane wave basis set and periodic boundary conditions.
Single-photon Coulomb explosion of methanol using broad bandwidth ultrafast EUV pulses.
Luzon, Itamar; Jagtap, Krishna; Livshits, Ester; Lioubashevski, Oleg; Baer, Roi; Strasser, Daniel
2017-05-31
Single-photon Coulomb explosion of methanol is instigated using the broad bandwidth pulse achieved through high-order harmonics generation. Using 3D coincidence fragment imaging of one molecule at a time, the kinetic energy release (KER) and angular distributions of the products are measured in different Coulomb explosion (CE) channels. Two-body CE channels breaking either the C-O or the C-H bonds are described as well as a proton migration channel forming H2O(+), which is shown to exhibit higher KER. The results are compared to intense-field Coulomb explosion measurements in the literature. The interpretation of broad bandwidth single-photon CE data is discussed and supported by ab initio calculations of the predominant C-O bond breaking CE channel. We discuss the importance of these findings for achieving time resolved imaging of ultrafast dynamics.
Guthmuller, Julien
2016-02-01
Sum-over-state (SOS) expressions to simulate absorption spectroscopy and resonance Raman (RR) scattering including Franck-Condon (FC) and Herzberg-Teller (HT) effects are described. Starting from the general SOS method, several simplified SOS formulae are derived. In particular, within the so-called independent mode displaced harmonic oscillator model, it is shown that including the vibronic structure in the absorption and RR spectra only requires the calculation of FC overlap integrals of the type , where g, e, and v stand for the electronic ground state, excited state, and vibrational quantum number, respectively. Additionally, an approximation of the latter approach is introduced, referred as the simplified Φe method, in which the FC factors are neglected. This method is advantageous from the computational point of view and it is demonstrated that it reproduces the main characteristics of the more involved approaches. The merits and drawbacks of the different methods are discussed by applying them to the prototypical compound of Rhodamine 6G. Overall, this work intends to unravel and clarify some differences in the SOS theories of RR scattering.
Proton radiography, nuclear cross sections and multiple Coulomb scattering
Energy Technology Data Exchange (ETDEWEB)
Sjue, Sky K. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2015-11-04
The principles behind proton radiography including multiple Coulomb scattering are discussed for a purely imaginary square well nucleus in the eikonal approximation. It is found that a very crude model can reproduce the angular dependence of the cross sections measured at 24 GeV/c. The largest differences are ~3% for the 4.56 mrad data, and ~4% for the 6.68 mrad data. The prospect of understanding how to model deterministically high-energy proton radiography over a very large range of energies is promising, but it should be tested more thoroughly.
Efficient Finite Element Calculation of Nγ
DEFF Research Database (Denmark)
Clausen, Johan; Damkilde, Lars; Krabbenhøft, K.
2007-01-01
This paper deals with the computational aspects of the Mohr-Coulomb material model, in particular the calculation of the bearing capacity factor Nγfor a strip and a circular footing.......This paper deals with the computational aspects of the Mohr-Coulomb material model, in particular the calculation of the bearing capacity factor Nγfor a strip and a circular footing....
Simbuca, using a graphics card to simulate Coulomb interactions in a penning trap
Van Gorp, S; Friedag, P; De Leebeeck, V; Tandecki, M; Weinheimer, C; Breitenfeldt, M; Traykov, E; Severijn, N; Mader, J; Soti, G; Iitaka, T; Herlert, A; Wauters, F; Zakoucky, D; Kozlov, V; Roccia, S
2011-01-01
In almost all cases, N-body simulations are limited by the computation time available. Coulomb interaction calculations scale with O(N(2)) with N the number of particles. Approximation methods exist already to reduce the computation time to O(NlogN) although calculating the interaction still dominates the total simulation time. We present Simbuca, a simulation package for thousands of ions moving in a Penning trap which will be applied for the WITCH experiment. Simbuca uses the output of the Cunbody-1 library, which calculates the gravitational interaction between entities on a graphics card, and adapts it for Coulomb calculations. Furthermore the program incorporates three realistic buffer gas models, the possibility of importing realistic electric and magnetic fieldmaps and different order integrators with adaptive step size and error control. The software is released under the GNU General Public License and free for use. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.
Transfer reactions below the Coulomb barrier
Energy Technology Data Exchange (ETDEWEB)
Napoli, D.R.; Stefanini, A.M.; Million, B.; Narayanasamy, M.; Prete, G.; Spolaore, P.; Li Zichang (INFN, Legnaro (Italy) Lab. Nazionali, Legnaro (Italy)); Moreno Gonzalez, H. (INFN, Legnaro (Italy) Lab. Nazionali, Legnaro (Italy) Dept. de Fisica Atomica y Nuclear, Univ. Sevilla (Spain)); Pollarolo, G. (Univ. Turin (Italy) INFN, Turin (Italy)); Beghini, S.; Montagnoli, G.; Scarlassara, F.; Segato, G.F.; Signorini, C.; Soramel, F. (Univ. Padua (Italy) INFN, Padua (Italy)); Rapisarda, A. (INFN, Catania (Italy))
1993-03-01
We report here on the measurements of one-particle transfer cross sections and quasi-elastic scattering of [sup 32]Si+[sup 64]Ni at energies around and well below the Coulomb barrier. The experiment has been performed with the Legnaro Recoil Mass Spectrometer. We have measured the excitation function at [theta][sub cm]=170deg from E[sub lab]=68.3 to 92.4 MeV and the angular distribution at E[sub lab]=81.3 MeV from [theta][sub cm]=120deg to 170deg. The results have been analysed in the framework of the complex WKB theory and the semiclassical approach based on Coulomb trajectories. (orig.).
Coulomb center instability in bilayer graphene
Oriekhov, D. O.; Sobol, O. O.; Gorbar, E. V.; Gusynin, V. P.
2017-10-01
In the low-energy two-band as well as four-band continuum models, we study the supercritical charge instability in gapped bilayer graphene in the field of an impurity charge when the lowest-energy bound state dives into the hole continuum. It is found that the screening effects are crucially important in bilayer graphene. If they are neglected, then the critical value for the impurity charge tends to zero as the gap Δ vanishes. If the screened Coulomb interaction is considered, then the critical charge tends to a finite value for Δ →0 . The different scalings of the kinetic energy of quasiparticles and the Coulomb interaction with respect to the distance to the charged impurity ensure that the wave function of the electron bound state does not shrink toward the impurity as its charge increases. This results in the absence of the fall-to-center phenomenon in bilayer graphene although the supercritical charge instability is realized.
On the one-dimensional Coulomb problem
Energy Technology Data Exchange (ETDEWEB)
Jaramillo, Benjamin [Instituto de Fisica, Universidad de Guanajuato, Loma del Bosque 103, Fracc. Lomas del Campestre, CP 37150 Leon, Guanajuato (Mexico); Martinez-y-Romero, R.P. [Facultad de Ciencias, Universidad Nacional Autonoma de Mexico, Apartado Postal 21-267, CP 04000, Coyoacan, D.F. (Mexico); Nunez-Yepez, H.N. [Departamento Fisica, Universidad Autonoma Metropolitana-Iztapalapa, Apartado Postal 55-534, CP 09340, Iztapalapa, D.F. (Mexico); Salas-Brito, A.L., E-mail: asb@correo.azc.uam.m [Laboratorio de Sistemas Dinamicos, Departamento de Ciencias Basicas, Universidad Autonoma Metropolitana-Azcapotzalco, Apartado Postal 21-267, CP 04000, Coyoacan, D.F. (Mexico)
2009-12-28
We analyse the one-dimensional Coulomb problem (1DCP) pointing out some mistaken beliefs on it. We show that no eigenstates of even or odd parity can represent states of the system. The 1DCP exhibits a sort of spontaneous breaking of parity. We also show that a superselection rule operates in the system. Such rule explains some of its peculiarities. We build the superpotential associated to the 1DCP.
Coulomb dissociation studies for astrophysical thermonuclear reactions
Energy Technology Data Exchange (ETDEWEB)
Motobayashi, T. [Dept. of Physics, Rikkyo Univ., Toshima, Tokyo (Japan)
1998-06-01
The Coulomb dissociation method was applied to several radiative capture processes of astrophysical interest. The method has an advantage of high experimental efficiency, which allow measurements with radioactive nuclear beams. The reactions {sup 13}N(p,{gamma}){sup 14}O and {sup 7}Be(p,{gamma}){sup 8}B are mainly discussed. They are the key reaction in the hot CNO cycle in massive stars and the one closely related to the solar neutrino problem, respectively. (orig.)
Rollins, John C.; Stein, Ross S.
2010-01-01
The Gorda deformation zone, a 50,000 km2 area of diffuse shear and rotation offshore northernmost California, has been the site of 20 M ≥ 5.9 earthquakes on four different fault orientations since 1976, including four M ≥ 7 shocks. This is the highest rate of large earthquakes in the contiguous United States. We calculate that the source faults of six recent M ≥ 5.9 earthquakes had experienced ≥0.6 bar Coulomb stress increases imparted by earthquakes that struck less than 9 months beforehand. Control tests indicate that ≥0.6 bar Coulomb stress interactions between M ≥ 5.9 earthquakes separated by Mw = 7.3 Trinidad earthquake are consistent with the locations of M ≥ 5.9 earthquakes in the Gorda zone until at least 1995, as well as earthquakes on the Mendocino Fault Zone in 1994 and 2000. Coulomb stress changes imparted by the 1980 earthquake are also consistent with its distinct elbow-shaped aftershock pattern. From these observations, we derive generalized static stress interactions among right-lateral, left-lateral and thrust faults near triple junctions.
Farrance, Ian; Frenkel, Robert
2014-02-01
The Guide to the Expression of Uncertainty in Measurement (usually referred to as the GUM) provides the basic framework for evaluating uncertainty in measurement. The GUM however does not always provide clearly identifiable procedures suitable for medical laboratory applications, particularly when internal quality control (IQC) is used to derive most of the uncertainty estimates. The GUM modelling approach requires advanced mathematical skills for many of its procedures, but Monte Carlo simulation (MCS) can be used as an alternative for many medical laboratory applications. In particular, calculations for determining how uncertainties in the input quantities to a functional relationship propagate through to the output can be accomplished using a readily available spreadsheet such as Microsoft Excel. The MCS procedure uses algorithmically generated pseudo-random numbers which are then forced to follow a prescribed probability distribution. When IQC data provide the uncertainty estimates the normal (Gaussian) distribution is generally considered appropriate, but MCS is by no means restricted to this particular case. With input variations simulated by random numbers, the functional relationship then provides the corresponding variations in the output in a manner which also provides its probability distribution. The MCS procedure thus provides output uncertainty estimates without the need for the differential equations associated with GUM modelling. The aim of this article is to demonstrate the ease with which Microsoft Excel (or a similar spreadsheet) can be used to provide an uncertainty estimate for measurands derived through a functional relationship. In addition, we also consider the relatively common situation where an empirically derived formula includes one or more 'constants', each of which has an empirically derived numerical value. Such empirically derived 'constants' must also have associated uncertainties which propagate through the functional relationship
Farrance, Ian; Frenkel, Robert
2014-01-01
The Guide to the Expression of Uncertainty in Measurement (usually referred to as the GUM) provides the basic framework for evaluating uncertainty in measurement. The GUM however does not always provide clearly identifiable procedures suitable for medical laboratory applications, particularly when internal quality control (IQC) is used to derive most of the uncertainty estimates. The GUM modelling approach requires advanced mathematical skills for many of its procedures, but Monte Carlo simulation (MCS) can be used as an alternative for many medical laboratory applications. In particular, calculations for determining how uncertainties in the input quantities to a functional relationship propagate through to the output can be accomplished using a readily available spreadsheet such as Microsoft Excel. The MCS procedure uses algorithmically generated pseudo-random numbers which are then forced to follow a prescribed probability distribution. When IQC data provide the uncertainty estimates the normal (Gaussian) distribution is generally considered appropriate, but MCS is by no means restricted to this particular case. With input variations simulated by random numbers, the functional relationship then provides the corresponding variations in the output in a manner which also provides its probability distribution. The MCS procedure thus provides output uncertainty estimates without the need for the differential equations associated with GUM modelling. The aim of this article is to demonstrate the ease with which Microsoft Excel (or a similar spreadsheet) can be used to provide an uncertainty estimate for measurands derived through a functional relationship. In addition, we also consider the relatively common situation where an empirically derived formula includes one or more ‘constants’, each of which has an empirically derived numerical value. Such empirically derived ‘constants’ must also have associated uncertainties which propagate through the functional
N-Protonated Isomers and Coulombic Barriers to Dissociation of Doubly Protonated Ala8Arg
Haeffner, Fredrik; Irikura, Karl K.
2017-10-01
Collision-induced dissociation (or tandem mass spectrometry, MS/MS) of a protonated peptide results in a spectrum of fragment ions that is useful for inferring amino acid sequence. This is now commonplace and a foundation of proteomics. The underlying chemical and physical processes are believed to be those familiar from physical organic chemistry and chemical kinetics. However, first-principles predictions remain intractable because of the conflicting necessities for high accuracy (to achieve qualitatively correct kinetics) and computational speed (to compensate for the high cost of reliable calculations on such large molecules). To make progress, shortcuts are needed. Inspired by the popular mobile proton model, we have previously proposed a simplified theoretical model in which the gas-phase fragmentation pattern of protonated peptides reflects the relative stabilities of N-protonated isomers, thus avoiding the need for transition-state information. For singly protonated Ala n ( n = 3-11), the resulting predictions were in qualitative agreement with the results from low-energy MS/MS experiments. Here, the comparison is extended to a model tryptic peptide, doubly protonated Ala8Arg. This is of interest because doubly protonated tryptic peptides are the most important in proteomics. In comparison with experimental results, our model seriously overpredicts the degree of backbone fragmentation at N9. We offer an improved model that corrects this deficiency. The principal change is to include Coulombic barriers, which hinder the separation of the product cations from each other. Coulombic barriers may be equally important in MS/MS of all multiply charged peptide ions. [Figure not available: see fulltext.
Coulomb-stable triply charged diatomic: HeY3+
Wesendrup, Ralf; Pernpointner, Markus; Schwerdtfeger, Peter
1999-11-01
Accurate relativistic coupled-cluster calculations show that the triply charged species HeY3+ is a stable molecule and represents the lightest diatomic trication that does not undergo a Coulomb fragmentation into charged fragments. The diatomic potential-energy curve is approximated by an extended Morse potential, and vibrational-rotational constants for HeY3+ are predicted (Re=224.3 pm, D0=0.394 eV, ωe=437 cm-1, ωexe=15.8 cm-1, Be=0.877 cm-1). It is further shown that the He-Y3+ bond can basically be described as a charge-induced dipole interaction.
Multiple Coulomb excitation experiment of {sup 68}Zn
Energy Technology Data Exchange (ETDEWEB)
Koizumi, M. E-mail: koizumi@jball4.tokai.jaeri.go.jp; Seki, A.; Toh, Y.; Osa, A.; Utsuno, Y.; Kimura, A.; Oshima, M.; Hayakawa, T.; Hatsukawa, Y.; Katakura, J.; Matsuda, M.; Shizuma, T.; Czosnyka, T.; Sugawara, M.; Morikawa, T.; Kusakari, H
2004-01-12
Coulomb excitation experiment was carried out with a {sup 68}Zn beam bombarding a {sup nat}Pb target. Two E2 matrix elements and the quadrupole moment of the 2{sub 1}{sup +} state were newly derived with the least-squares search code GOSIA. The potential energy surface (PES) was calculated with the Nilsson-Strutinsky model, showing two shallow minima: the first minimum does not contain the 1g{sub 9/2} orbit below the Fermi surface, while the second minimum does. The ground state band and the intruder band seem to be constructed on the first and the second minimum, respectively. As for the ground state band, the asymmetric rotor model and the IBM in O(6) limit reproduced the experimental values rather well. The shallow PES may suggest instability of the shape. The ground state band structure may be explained assuming a soft triaxial deformation.
Kauweloa, Kevin I; Gutierrez, Alonso N; Stathakis, Sotirios; Papanikolaou, Niko; Mavroidis, Panayiotis
2016-07-01
A toolkit has been developed for calculating the 3-dimensional biological effective dose (BED) distributions in multi-phase, external beam radiotherapy treatments such as those applied in liver stereotactic body radiation therapy (SBRT) and in multi-prescription treatments. This toolkit also provides a wide range of statistical results related to dose and BED distributions. MATLAB 2010a, version 7.10 was used to create this GUI toolkit. The input data consist of the dose distribution matrices, organ contour coordinates, and treatment planning parameters from the treatment planning system (TPS). The toolkit has the capability of calculating the multi-phase BED distributions using different formulas (denoted as true and approximate). Following the calculations of the BED distributions, the dose and BED distributions can be viewed in different projections (e.g. coronal, sagittal and transverse). The different elements of this toolkit are presented and the important steps for the execution of its calculations are illustrated. The toolkit is applied on brain, head & neck and prostate cancer patients, who received primary and boost phases in order to demonstrate its capability in calculating BED distributions, as well as measuring the inaccuracy and imprecision of the approximate BED distributions. Finally, the clinical situations in which the use of the present toolkit would have a significant clinical impact are indicated. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.
DEFF Research Database (Denmark)
Biltoft-Jensen, Anja Pia; Saxholt, Erling; Knuthsen, Pia
Objective: Constantly updated food data that reflect the food supply, such as the recently published http://frida.fooddata.dk, is essential for recipe calculation in dietary assessment. The objective of this study was to compare the content of selected nutrients estimated by recipe calculation...... and chemical analysis of fast food based on data from http://frida.fooddata.dk. Materials and methods: New fast food data in http://frida.fooddata.dk was based on 135 samples of ready to eat fast foods as burgers and sandwiches collected from fast food outlets, separated into their recipe components which were...... weighed. Typical components were bread, French fries, vegetables, meat, and dressings. The fast foods were analyzed and the content of energy, protein, saturated fat, iron, thiamin, potassium and sodium were compared to recipe calculation. Wilcoxon Signed Rank test, Spearman correlation coefficients...
Cheng, X.
2016-12-01
After Lamjung Mw 7.8 earthquake in Nepal happened, rearrangement of stresses in the crust commonly leads to subsequent damaging earthquakes. We carry out a calculation to investigate the Coulomb stress changes in certain filed. Using models of regional faults designed according to south Tibet-Nepal structure, we present calculations of the coseismic stress changes that resulted from the 25 April, 2015 Lamjung earthquake and show some indicative significant stress increase. We use the Coulomb 3.3 model to estimate Coulomb stress and the calculations are conducted in an elastic half-space with uniform isotropic elastic medium. We set up receiver faults to be normal faults to the north of the seismogenic fault according to tectonic features. The results show that the aftershocks are associated with a zone of increased Coulomb stress caused by the main rupture, and the normal faults to the north of the seismogenic faults mainly have increased Coulomb stress, with the western normal faults having greater changes in Coulomb stress than the easternmost faults (cf. figure). This indicates greater risk from the western normal faults than from the easternmost faults, and we should pay attention to studying these normal faults in the future. As for seismogenic fault, which is considered as the Main Himalaya Thrust (MHT), the western part, at 10 20 km, has clearly higher Coulomb stress changes of values up to 0.1bar (0.01MPa). This indicates that the stress may have transferred to the west of the MHT more easily than to the east. This big event might have led to more sufficient rupture to the eastern part than to the west, which is useful for identifying potential future rupture zones and carrying out earthquake mitigation.
Rollins, J. C.; Ely, G. P.; Jordan, T. H.
2011-12-01
To study static stress interactions between faults in southern California and identify cases where one large earthquake could trigger another, we select fourteen M>7 events simulated by the SCEC/CME CyberShake project and calculate the Coulomb stress changes those events impart to major fault surfaces in the UCERF2 fault model for the region. CyberShake simulates between 6 and 32 slip distributions for each event at a slip sampling resolution of 1 km, and we calculate stress changes on fault surfaces at the same resolution, a level of detail which is unprecedented in studies of stress transfer and which allows us to study the way that variabilities in slip on the source can affect imparted stress changes. We find that earthquakes rupturing the southern San Andreas fault generally decrease Coulomb stress on right-lateral faults in the Los Angeles basin, while M>7 events on the San Jacinto, Elsinore, Newport-Inglewood and Palos Verdes faults generally decrease stress on parallel right-lateral faults but increase Coulomb stress on the Mojave or San Bernardino sections of the San Andreas. Stress interactions between strike-slip and thrust faults and between the San Andreas and Garlock faults depend on the rupture area of the source. Coulomb stress changes imparted by simulated SAF events to locations on the San Jacinto and Garlock faults within ~8 km of the San Andreas appear to be influenced more by the nearby distribution of high and low slip on the San Andreas than by the overall slip distribution across the entire rupture. Using a simplified model, we calculate that an area of no slip surrounded by high slip on a rupture imparts strong Coulomb stress increases ≤7 km to either side of the source fault, possibly explaining the apparent ~8-km range of influence of local slip on the San Andreas. Additionally, we devise a method for evaluating uncertainty values in Coulomb stress changes caused by uncertainties in the strike, dip and rake of the receiver fault. These
Liu, Jian; Xu, Chang; Ren, Zhongzhou
2017-04-01
Background: Combining the relativistic mean-field (RMF) model and distorted wave Born approximation (DWBA) method, Coulomb form factors for elastic electron scattering have been studied for several stable nuclei (208Pb, 40Ca, 32S, and 24Mg) with a methodology that can be extended to exotic nuclei. Purpose: Previous studies on nuclear Coulomb form factors by the RMF+DWBA method were mainly based on the spherical RMF model. This work aims to further extend the studies to the axially deformed RMF model. Method: The nuclear proton density distributions are first calculated by the deformed RMF model. Next, the axially deformed density distributions are expanded into multipole components. With the spherical ρ0 components, the Coulomb form factors of even-even nuclei are calculated by the DWBA method. Results: For spherical nuclei, the nuclear Coulomb form factors obtained with the deformed RMF model almost coincide with those from the spherical RMF model. For deformed nuclei, Coulomb form factors obtained with the deformed RMF model agree better with the experimental data at the diffraction minima and at high momentum transfers. Conclusions: Results indicate the proton densities calculated from the axially deformed RMF model are valid and reasonable. The electron-scattering experiments will soon be available for exotic nuclei, and the studies in this paper are helpful to interpret the experimental data of deformed exotic nuclei.
DEFF Research Database (Denmark)
Muniruzzaman, Muhammad; Rolle, Massimo
the capability of the proposed two-dimensional multicomponent approach to describe transport of charged species and to accurately capture the Coulombic interactions between the ions, which are clearly observed in the flow-through experiments. Furthermore, the model allowed us to directly quantify and visualize...... the ionic interactions by mapping the Coulombic cross-coupling between the dispersive fluxes of the charged species in the heterogeneous domains. The outcomes of this study are important in many subsurface applications including migration of contaminants and propagation of reaction fronts....
Realization of collective strong coupling with ion Coulomb crystals in an optical cavity
DEFF Research Database (Denmark)
Herskind, Peter Fønss; Dantan, Aurélien; Marler, Joan
2009-01-01
quantum-information-processing networks 11, 12 hence requires devices to efficiently couple photons and stationary qubits. Here, we present the first CQED experiments demonstrating that the collective strong-coupling regime 2 can be reached in the interaction between a solid in the form of an ion Coulomb...... crystal 16 and an optical field. The obtained coherence times are in the millisecond range and indicate that Coulomb crystals positioned inside optical cavities are promising for realizing a variety of quantum-information devices, including quantum repeaters 12 and quantum memories for light 17, 18...
Action principle for Coulomb collisions in plasmas
Hirvijoki, Eero
2015-01-01
In this letter we derive an action principle for Coulomb collisions in plasmas. Although no natural Lagrangian exists for the Landau-Fokker-Planck equation, an Eulerian variational formulation is found considering the system of partial differential equations that couple the distribution function and the Rosenbluth potentials. Exact conservation laws are derived after generalizing the energy-momentum stress tensor for second order Lagrangians and, in the case of a test-particle population in a given plasma background, the action principle is shown to correspond to the Langevin equation for individual particles. Being suitable for discretization, the presented action allows construction of variational integrators. Numerical implementation is left for a future study.
Resonances in the two centers Coulomb system
Energy Technology Data Exchange (ETDEWEB)
Seri, Marcello
2012-09-14
In this work we investigate the existence of resonances for two-centers Coulomb systems with arbitrary charges in two and three dimensions, defining them in terms of generalized complex eigenvalues of a non-selfadjoint deformation of the two-center Schroedinger operator. After giving a description of the bifurcation of the classical system for positive energies, we construct the resolvent kernel of the operators and we prove that they can be extended analytically to the second Riemann sheet. The resonances are then defined and studied with numerical methods and perturbation theory.
Nonequilibrium quantum thermodynamics in Coulomb crystals
Cosco, F.; Borrelli, M.; Silvi, P.; Maniscalco, S.; De Chiara, G.
2017-06-01
We present an in-depth study of the nonequilibrium statistics of the irreversible work produced during sudden quenches in proximity to the structural linear-zigzag transition of ion Coulomb crystals in 1+1 dimensions. By employing both an analytical approach based on a harmonic expansion and numerical simulations, we show the divergence of the average irreversible work in proximity to the transition. We show that the nonanalytic behavior of the work fluctuations can be characterized in terms of the critical exponents of the quantum Ising chain. Due to the technological advancements in trapped-ion experiments, our results can be readily verified.
The proton-proton scattering without Coulomb force renormalization
Directory of Open Access Journals (Sweden)
Glöckle W.
2010-04-01
Full Text Available We demonstrate numerically that proton-proton (pp scattering observables can be determined directly by standard short range methods using a screened pp Coulomb force without renormalization. We numerically investigate solutions of the 3-dimensional Lippmann-Schwinger (LS equation for an exponentially screened Coulomb potential. For the limit of large screening radii we conﬁrm analytically predicted properties for oﬀ-shell, half-shell and on-shell elements of the Coulomb t-matrix.
Coulomb implosion mechanism of negative ion acceleration in laser plasmas
Nakamura, T.; Fukuda, Y.; Yogo, A.; Tampo, M.; Kando, M.; Hayashi, Y.; Kameshima, T.; Pirozhkov, A. S.; Esirkepov, T. Zh.; Pikuz, T. A.; Faenov, A. Ya.; Daido, H.; Bulanov, S. V.
2008-01-01
Coulomb implosion mechanism of the negatively charged ion acceleration in laser plasmas is proposed. When a cluster target is irradiated by an intense laser pulse and the Coulomb explosion of positively charged ions occurs, the negative ions are accelerated inward. The maximum energy of negative ions is several times lower than that of positive ions. The theoretical description and Particle-in-Cell simulation of the Coulomb implosion mechanism and the evidence of the negative ion acceleration...
Correlated Coulomb drag in capacitively coupled quantum-dot structures
DEFF Research Database (Denmark)
Kaasbjerg, Kristen; Jauho, Antti-Pekka
2016-01-01
We study theoretically Coulomb drag in capacitively coupled quantum dots (CQDs) -- a biasdriven dot coupled to an unbiased dot where transport is due to Coulomb mediated energy transfer drag. To this end, we introduce a master-equation approach which accounts for higher-order tunneling (cotunneling......) processes as well as energy-dependent lead couplings, and identify a mesoscopic Coulomb drag mechanism driven by nonlocal multi-electron cotunneling processes. Our theory establishes the conditions for a nonzero drag as well as the direction of the drag current in terms of microscopic system parameters...... on Coulomb drag in CQD systems....
Transport Through a Coulomb Blockaded Majorana Nanowire
Zazunov, Alex; Egger, Reinhold; Yeyati, Alfredo Levy; Hützen, Roland; Braunecker, Bernd
In one-dimensional (1D) quantum wires with strong spin-orbit coupling and a Zeeman field, a superconducting substrate can induce zero-energy Majorana bound states located near the ends of the wire. We study electronic properties when such a wire is contacted by normal metallic or superconducting electrodes. A special attention is devoted to Coulomb blockade effects. We analyze the "Majorana single-charge transistor" (MSCT), i.e., a floating Majorana wire contacted by normal metallic source and drain contacts, where charging effects are important. We describe Coulomb oscillations in this system and predict that Majorana fermions could be unambiguously detected by the emergence of sideband peaks in the nonlinear differential conductance. We also study a superconducting variant of the MSCT setup with s-wave superconducting (instead of normal-conducting) leads. In the noninteracting case, we derive the exact current-phase relation (CPR) and find π-periodic behavior with negative critical current for weak tunnel couplings. Charging effects then cause the anomalous CPR I(\\varphi ) = Ic\\cos \\varphi, where the parity-sensitive critical current I c provides a signature for Majorana states.
Coulomb crystallization of highly charged ions.
Schmöger, L; Versolato, O O; Schwarz, M; Kohnen, M; Windberger, A; Piest, B; Feuchtenbeiner, S; Pedregosa-Gutierrez, J; Leopold, T; Micke, P; Hansen, A K; Baumann, T M; Drewsen, M; Ullrich, J; Schmidt, P O; López-Urrutia, J R Crespo
2015-03-13
Control over the motional degrees of freedom of atoms, ions, and molecules in a field-free environment enables unrivalled measurement accuracies but has yet to be applied to highly charged ions (HCIs), which are of particular interest to future atomic clock designs and searches for physics beyond the Standard Model. Here, we report on the Coulomb crystallization of HCIs (specifically (40)Ar(13+)) produced in an electron beam ion trap and retrapped in a cryogenic linear radiofrequency trap by means of sympathetic motional cooling through Coulomb interaction with a directly laser-cooled ensemble of Be(+) ions. We also demonstrate cooling of a single Ar(13+) ion by a single Be(+) ion-the prerequisite for quantum logic spectroscopy with a potential 10(-19) accuracy level. Achieving a seven-orders-of-magnitude decrease in HCI temperature starting at megakelvin down to the millikelvin range removes the major obstacle for HCI investigation with high-precision laser spectroscopy. Copyright © 2015, American Association for the Advancement of Science.
DEFF Research Database (Denmark)
weighed. Typical components were bread, French fries, vegetables, meat, and dressings. The fast foods were analyzed and the content of energy, protein, saturated fat, iron, thiamin, potassium and sodium were compared to recipe calculation. Wilcoxon Signed Rank test, Spearman correlation coefficients...... and Bland-Altman plots were used for comparing the two methods. Results: Overall there were differences between the chemical and recipe analysis for energy, protein, saturated fat and iron (P0.05). The error percentage was largest for saturated fat (28...
Energy Technology Data Exchange (ETDEWEB)
Lyutorovich, N. [Forschungszentrum Juelich, Institut fuer Kernphysik, Juelich (Germany); Institute of Physics S. Petersburg University, S. Petersburg (Russian Federation); Speth, J. [Forschungszentrum Juelich, Institut fuer Kernphysik, Juelich (Germany); Institute of Nuclear Physics, PAN, Cracow (Poland); Avdeenkov, A. [Forschungszentrum Juelich, Institut fuer Kernphysik, Juelich (Germany); Institute of Physics and Power Engineering, Obninsk (Russian Federation); Gruemmer, F.; Krewald, S. [Forschungszentrum Juelich, Institut fuer Kernphysik, Juelich (Germany); Kamerdzhiev, S. [Institute of Physics and Power Engineering, Obninsk (Russian Federation); Tselyaev, V.I. [Institute of Physics S. Petersburg University, S. Petersburg (Russian Federation)
2008-09-15
The Green's function method in the Quasiparticle Time Blocking Approximation is applied to nuclear excitations in {sup 132}Sn and {sup 208}Pb. The calculations are performed self-consistently using a Skyrme interaction. The method combines the conventional RPA with an exact single-particle continuum treatment and considers in a consistent way the particle-phonon coupling. We reproduce not only the experimental values of low-and high-lying collective states but we also obtain fair agreement with the data of non-collective low-lying states that are strongly influenced by the particle-phonon coupling. (orig.)
Coulomb singularity in the transverse momentum distribution for strong-field single ionization
Energy Technology Data Exchange (ETDEWEB)
Rudenko, A; Zrost, K; Ergler, Th; Voitkiv, A B; Najjari, B; Jesus, V L B de; Feuerstein, B; Schroeter, C D; Moshammer, R; Ullrich, J [Max-Planck-Institut fuer Kernphysik, D-69029 Heidelberg (Germany)
2005-06-14
We present high-resolution momentum distributions of ions and electrons created in single ionization of He, Ne and Ar targets by intense (0.15-2 PW cm{sup -2}) short-pulsed (25 fs) linearly polarized laser fields in the direction perpendicular to the polarization. Instead of a Gaussian shape predicted by standard tunnelling theory, the experimental data exhibit a sharp cusp-like peak at zero transverse momentum. The comparison of experimental data with (i) calculations performed within the strong-field approximation employing a Coulomb-Volkov wavefunction to model the final electron state and (ii) results of recent semiclassical calculations, shows that the 'cusp' appears due to the long-range Coulomb interaction between the emitted electron and the remaining ion. A similar structure was previously observed for ion-atom collisions. (letter to the editor)
Kornobis, Karina; Wong, Bryan M; Lodowski, Piotr; Jaworska, Maria; Andruniów, Tadeusz; Rudd, Kenneth; Kozlowski, Pawel M; 10.1021/jp110914y
2011-01-01
Time-dependent density functional theory (TD-DFT) and correlated ab initio methods have been applied to the electronically excited states of vitamin B12 (cyanocobalamin or CNCbl). Different experimental techniques have been used to probe the excited states of CNCbl, revealing many issues that remain poorly understood from an electronic structure point of view. Due to its efficient scaling with size, TD-DFT emerges as one of the most practical tools that can be used to predict the electronic properties of these fairly complex molecules. However, the description of excited states is strongly dependent on the type of functional used in the calculations. In the present contribution, the choice of a proper functional for vitamin B12 was evaluated in terms of its agreement with both experimental results and correlated ab initio calculations. Three different functionals, i.e. B3LYP, BP86, and LC-BLYP, were tested. In addition, the effect of relative contributions of DFT and HF to the exchange-correlation functional ...
Spatial mode effects in a cavity-EIT based quantum memory with ion Coulomb crystals
DEFF Research Database (Denmark)
Zangenberg, Kasper Rothe; Dantan, Aurelien Romain; Drewsen, Michael
2012-01-01
Quantum storage and retrieval of light in ion Coulomb crystals using cavity electromagnetically induced transparency are investigated theoretically. It is found that when both the control and the probe fields are coupled to the same spatial cavity mode, their transverse mode profile affects...... the quantum memory efficiency in a non-trivial way. Under such conditions, the control-field parameters and crystal dimensions that maximize the memory efficiency are calculated....
On the lattice dynamics of metallic hydrogen and other Coulomb systems
Beck, H.; Straus, D.
1975-01-01
Numerical results for the phonon spectra of metallic hydrogen and other Coulomb systems in cubic lattices are presented. In second order in the electron-ion interaction, the behavior of the dielectric function of the interacting electron gas for arguments around the seond Fermi harmonic leads to drastic Kohn anomalies and even to imaginary phonon frequencies. Third-order band-structure corrections are also calculated. Properties of self-consistent phonons and the validity of the adiabatic approximation are discussed.
Marashdeh, A.; Frankcombe, T.J.
2008-01-01
The dehydrogenation enthalpies of Ca(AlH4)2, CaAlH5, and CaH2+6LiBH4 have been calculated using density functional theory calculations at the generalized gradient approximation level. Harmonic phonon zero point energy (ZPE) corrections have been included using Parlinski’s direct method. The
Elastic scattering of 9Be+51V near the Coulomb barrier
Directory of Open Access Journals (Sweden)
Morales-Rivera J.C.
2016-01-01
Full Text Available Elastic scattering angular distributions for the 9Be+51V system were measured at three near Coulomb barrier energies, Elab = 16.35, 17.44 and 18.53 MeV. The data were analyzed by using a Semimicroscopic Optical Model. This combines a microscopic calculation of the mean-field double folding potential and a phenomenological construction of the dynamical polarization potential. The calculations reproduced the data very well and the total reaction cross sections were also calculated.
Cluster structure and Coulomb shift in two-center mirror systems
Nakao, M.; Umehara, H.; Sonoda, S.; Ebata, S.; Ito, M.
2017-11-01
The α + 14C elastic scattering and the nuclear structure of its compound systems, 18O = α + 14C, are analyzed on the basis of the semi-microscopic model. The α + 14C interaction potential is constructed from the double folding (DF) model with the effective nucleon-nucleon interaction of the density-dependent Michigan 3-range Yukawa. The DF potential is applied to the α+14C elastic scattering in the energy range of Eα/Aα = 5.5 8.8 MeV, and the observed differential cross sections are reasonably reproduced. The energy spectra of 18O are calculated by employing the orthogonality condition model (OCM) plus the absorbing boundary condition (ABC). The OCM + ABC calculation predicts the formation of the 0+ resonance around E = 3MeV with respect to the α threshold, which seems to correspond to the resonance identified in the recent experiment. We also apply the OCM + ABC calculation to the mirror system, such as 18Ne = α+14O, and the Coulomb shift of 18O - 18Ne is evaluated. We have found that the Coulomb shift is clearly reduced in the excited 0+ state due to the development of the α cluster structure. This result strongly supports that the Coulomb shift is a candidate of new probe to identify the clustering phenomena.
Energy Technology Data Exchange (ETDEWEB)
Fakir, H.; Gaede, S.; Mulligan, M.; Chen, J. Z. [Department of Physics, London Regional Cancer Program, London, Ontario N6A 4L6 (Canada)
2012-07-15
Purpose: To design a versatile, nonhomogeneous insert for the dose verification phantom ArcCHECK{sup Trade-Mark-Sign} (Sun Nuclear Corp., FL) and to demonstrate its usefulness for the verification of dose distributions in inhomogeneous media. As an example, we demonstrate it can be used clinically for routine quality assurance of two volumetric modulated arc therapy (VMAT) systems for lung stereotactic body radiation therapy (SBRT): SmartArc{sup Registered-Sign} (Pinnacle{sup 3}, Philips Radiation Oncology Systems, Fitchburg, WI) and RapidArc{sup Registered-Sign} (Eclipse{sup Trade-Mark-Sign }, Varian Medical Systems, Palo Alto, CA). Methods: The cylindrical detector array ArcCHECK{sup Trade-Mark-Sign} has a retractable homogeneous acrylic insert. In this work, we designed and manufactured a customized heterogeneous insert with densities that simulate soft tissue, lung, bone, and air. The insert offers several possible heterogeneity configurations and multiple locations for point dose measurements. SmartArc{sup Registered-Sign} and RapidArc{sup Registered-Sign} plans for lung SBRT were generated and copied to ArcCHECK{sup Trade-Mark-Sign} for each inhomogeneity configuration. Dose delivery was done on a Varian 2100 ix linac. The evaluation of dose distributions was based on gamma analysis of the diode measurements and point doses measurements at different positions near the inhomogeneities. Results: The insert was successfully manufactured and tested with different measurements of VMAT plans. Dose distributions measured with the homogeneous insert showed gamma passing rates similar to our clinical results ({approx}99%) for both treatment-planning systems. Using nonhomogeneous inserts decreased the passing rates by up to 3.6% in the examples studied. Overall, SmartArc{sup Registered-Sign} plans showed better gamma passing rates for nonhomogeneous measurements. The discrepancy between calculated and measured point doses was increased up to 6.5% for the nonhomogeneous
Yousfi, M.; Merbahi, N.; Reichert, F.; Petchanka, A.
2017-03-01
Measurements of breakdown voltage Vb, gas temperature Tg, and density N and the associated critical electric field Ecr/N are performed in hot dissociated SF6 highly diluted in argon and in hot dissociated SF6 mixed with PTFE (Polytetrafluoroethylene or C2F4) also highly diluted in argon. Gases are heated using a microwave source and optical emission spectroscopy is used for measurements of Tg and N while Vb is measured from a specific inter-electrode arrangement placed inside of the cell of the hot gas conditioning. The experimental Ecr/N data in the numerous considered cases of gas temperatures and compositions have been used to evaluate and validate the sets of the collision cross sections of the 11 species involved in hot dissociated SF6 (i.e., SF6, SF5, SF4, S2F2, SF3, SF2, SF, S2, F2, F, and S), the 13 additional species involved either in hot C2F4 or CF4 (C2F6, C2F4, C2F2, CF4, CF3, CF2, CF, F2, F and carbon species as C, C2, C3, C4) and also the 2 further species (CS and CS2) present only in the considered mixtures SF6 + C2F4. The fitted sets of collision cross sections of all these 26 species are then used without argon dilution in hot SF6 and hot SF6 + C2F4 mixtures to calculate and to analyze the Ecr/N data obtained for a wide range of gas temperature (up to 4000 K) and gas pressure (8 bar and more) using a rigorous multi-term solution of the Boltzmann equation for electron energy distribution function and standard calculations of hot gas composition for the species proportions. Such Ecr/N data have been then successfully used to evaluate from a Computational Fluid Dynamics model the switching capacity at terminal fault from a coupled simulation of the electrostatic field and the hot gas flow after current zero.
Antilocalization of Coulomb Blockade in a Ge-Si Nanowire
DEFF Research Database (Denmark)
Higginbotham, Andrew P.; Kuemmeth, Ferdinand; Larsen, Thorvald Wadum
2014-01-01
The distribution of Coulomb blockade peak heights as a function of magnetic field is investigated experimentally in a Ge-Si nanowire quantum dot. Strong spin-orbit coupling in this hole-gas system leads to antilocalization of Coulomb blockade peaks, consistent with theory. In particular, the peak...
Multiple Coulomb excitation of a {sup 76}Ge beam
Energy Technology Data Exchange (ETDEWEB)
Toh, Y. [Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan)]. E-mail: toh@jball4.tokai.jaeri.go.jp; Oshima, M.; Hayakawa, T.; Osa, A.; Koizumi, M.; Hatsukawa, Y.; Katakura, J.; Shinohara, N.; Matsuda, M. [Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan); Czosnyka, T. [Heavy Ion Laboratory, Warsaw University, Warsaw (Poland); Kusakari, H. [Chiba University, Inage-ku, Chiba (Japan); Sugawara, M. [Chiba Institute of Technology, Narashino, Chiba (Japan)
2001-07-01
A multiple Coulomb excitation experiment on a {sup 76}Ge beam was performed using a {sup nat}Pb target. The relative excitation probabilities were measured as a function of the projectile scattering-angle. 15 E2 matrix elements, including diagonal ones, for seven low-lying states were determined using the least-squares search code GOSIA. The expectation values of centroid for the magnitude of the intrinsic frame E2 properties show that the ground state is weakly deformed, while the shape of the 0{sub 2}{sup +} level is almost spherical. The 2{sub 2}{sup +} state is found to be a band head of the {gamma} vibrational band and the 4{sub 2}{sup +} state is a member of this band. (author)
Coulomb interaction effect in tilted Weyl fermion in two dimensions
Isobe, Hiroki; Nagaosa, Naoto
Weyl fermions with tilted linear dispersions characterized by several different velocities appear in some systems including the quasi-two-dimensional organic semiconductor α-(BEDT-TTF)2I3 and three-dimensional WTe2. The Coulomb interaction between electrons modifies the velocities in an essential way in the low energy limit, where the logarithmic corrections dominate. Taking into account the coupling to both the transverse and longitudinal electromagnetic fields, we derive the renormalization group equations for the velocities of the tilted Weyl fermions in two dimensions, and found that they increase as the energy decreases and eventually hit the velocity of light c to result in the Cherenkov radiation. Especially, the system restores the isotropic Weyl cone even when the bare Weyl cone is strongly tilted and the velocity of electrons becomes negative in certain directions.
Simplistic Coulomb Forces in Molecular Dynamics
DEFF Research Database (Denmark)
Hansen, Jesper Schmidt; Schrøder, Thomas; Dyre, J. C.
2012-01-01
measures for the convergence of the Wolf method to the Ewald summation method. The SF approximation is also tested for the SPC/Fw model of liquid water at room temperature, showing good agreement with both the Wolf and the particle mesh Ewald methods; this confirms previous findings [Fennell, C. J......In this paper we compare the Wolf method to the shifted forces (SF) method for efficient computer simulation of bulk systems with Coulomb forces, taking results from the Ewald summation and particle mesh Ewald methods as representing the true behavior. We find that for the Hansen–McDonald molten...... salt model the SF approximation overall reproduces the structural and dynamical properties as accurately as does the Wolf method. It is shown that the optimal Wolf damping parameter depends on the property in focus and that neither the potential energy nor the radial distribution function are useful...
Tabletop Nucleosynthesis Driven by Cluster Coulomb Explosion
Last, Isidore; Jortner, Joshua
2006-10-01
Coulomb explosion of completely ionized (CH4)n, (NH3)n, and (H2O)n clusters will drive tabletop nuclear reactions of protons with C6+12, N7+14, and O8+16 nuclei, extending the realm of nuclear reactions driven by ultraintense laser-heterocluster interaction. The realization for nucleosynthesis in exploding cluster beams requires complete electron stripping from the clusters (at laser intensities IM≥1019Wcm-2), the utilization of nanodroplets of radius 300 700 Å for vertical ionization, and the attainment of the highest energies for the nuclei (i.e., ˜30MeV for heavy nuclei and ˜3MeV for protons).
Relativistic Coulomb excitation of 88Kr
Moschner, K.; Blazhev, A.; Jolie, J.; Warr, N.; Boutachkov, P.; Bednarczyk, P.; Sieja, K.; Algora, A.; Ameil, F.; Bentley, M. A.; Brambilla, S.; Braun, N.; Camera, F.; Cederkäll, J.; Corsi, A.; Danchev, M.; DiJulio, D.; Fahlander, C.; Gerl, J.; Giaz, A.; Golubev, P.; Górska, M.; Grebosz, J.; Habermann, T.; Hackstein, M.; Hoischen, R.; Kojouharov, I.; Kurz, N.; Mǎrginean, N.; Merchán, E.; Möller, T.; Naqvi, F.; Nara Singh, B. S.; Nociforo, C.; Pietralla, N.; Pietri, S.; Podolyák, Zs.; Prochazka, A.; Reese, M.; Reiter, P.; Rudigier, M.; Rudolph, D.; Sava, T.; Schaffner, H.; Scruton, L.; Taprogge, J.; Thomas, T.; Weick, H.; Wendt, A.; Wieland, O.; Wollersheim, H.-J.
2016-11-01
To investigate the systematics of mixed-symmetry states in N =52 isotones, a relativistic Coulomb excitation experiment was performed during the PreSPEC campaign at the GSI Helmholtzzentrum für Schwerionenforschung to determine E 2 transition strengths to 2+ states of the radioactive nucleus 88Kr. Absolute transition rates could be measured towards the first and third 2+ states. For the latter a mixed-symmetry character is suggested on the basis of the indication for a strong M 1 transition to the fully symmetric 21+ state, extending the knowledge of the N =52 isotones below Z =40 . A comparison with the proton-neutron interacting boson model and shell-model predictions is made and supports the assignment.
Study on Coulomb explosions of ion mixtures
Boella, E; D'Angola, A; Coppa, G; Silva, L O
2015-01-01
The paper presents a theoretical work on the dynamics of Coulomb explosion for spherical nanoplasmas composed by two different ion species. Particular attention has been dedicated to study the energy spectra of the ions with the larger charge-to-mass ratio. The connection between the formation of shock shells and the energy spread of the ions has been the object of a detailed analysis, showing that under particular conditions the width of the asymptotic energy spectrum tends to become very narrow, which leads to a multi-valued ion phase-space. The conditions to generate a quasi mono-energetic ion spectrum have been rigorously demonstrated and verifed by numerical simulations, using a technique that, exploiting the spherical symmetry of the problem, allows one to obtain very accurate and precise results.
Coulomb dissociation of light unstable nuclei
Energy Technology Data Exchange (ETDEWEB)
Kido, Toshihiko [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Yabana, Kazuhiro; Suzuki, Yoshiyuki
1997-05-01
The aim of this study is that a simulation method applicable to the atomic nucleus with neutron halo structure developed till now is applied to a wider range unstable nucleus containing proton excess nucleus to also attribute understanding of nuclear reaction with interest in astronomical nuclear reaction. The proton dissociation energy in {sup 8}B nucleus is small value of 138 eV, which is thought to have a structure of proton at the most outer shell bound much weakly by core nucleus and spread in thinner thickness. For the coulomb excitation of such weak bound system, quantum theoretical and non-perturbational treatment is important. Therefore, 3-dimensional time-dependent Schroedinger equation on relative wave function of the core nucleus {sup 7}Be and halo proton p will be dissolved in time space and will execute a time developmental simulation. (G.K.)
Gauge Theories on the Coulomb Branch
Schwarz, John H.
We construct the world-volume action of a probe D3-brane in AdS5 × S5 with N units of flux. It has the field content, symmetries, and dualities of the U(1) factor of 𝒩 = 4 U(N + 1) super Yang-Mills theory, spontaneously broken to U(N) × U(1) by being on the Coulomb branch, with the massive fields integrated out. This motivates the conjecture that it is the exact effective action, called a highly effective action (HEA). We construct an SL(2, Z) multiplet of BPS soliton solutions of the D3-brane theory (the conjectured HEA) and show that they reproduce the electrically charged massive states that have been integrated out as well as magnetic monopoles and dyons. Their charges are uniformly spread on a spherical surface, called a soliton bubble, which is interpreted as a phase boundary.
Energy Technology Data Exchange (ETDEWEB)
Fazlali, Alireza; Koranian, Parvaneh [Arak University, Arak (Iran, Islamic Republic of); Beigzadeh, Reza [Islamic Azad University, Kermanshah (Iran, Islamic Republic of); Rahimi, Masoud [Razi University, Kermanshah (Iran, Islamic Republic of)
2013-09-15
A feed forward three-layer artificial neural network (ANN) model was developed for VLE prediction of ternary systems including ionic liquid (IL) (water+ethanol+1-butyl-3- methyl-imidazolium acetate), in a relatively wide range of IL mass fractions up to 0.8, with the mole fractions of ethanol on IL-free basis fixed separately at 0.1, 0.2, 0.4, 0.6, 0.8, and 0.98. The output results of the ANN were the mole fraction of ethanol in vapor phase and the equilibrium temperature. The validity of the model was evaluated through a test data set, which were not employed in the training case of the network. The performance of the ANN model for estimating the mole fraction and temperature in the ternary system including IL was compared with the non-random-two-liquid (NRTL) and electrolyte non-random-two- liquid (eNRTL) models. The results of this comparison show that the ANN model has a superior performance in predicting the VLE of ternary systems including ionic liquid.
Tiotsop, M.; Fotue, A. J.; Kenfack, S. C.; Fotsin, H. B.; Fai, L. C.
2016-09-01
In the following study, the time evolution of the quantum mechanical state of a magnetopolaron using the Pekar type variational method on the electric-LO-phonon was considered. A strong coupling of polaron in triangular RbCl quantum dot with Coulomb impurity was duly derived. The Eigen energies and the Eigen functions of the ground state and the first excited state were obtained respectively. The obtained system in a quantum dot was treated as a two-level quantum system qubit and the numerical calculations were performed. The relations of polaron life time, the probability density, the Coulomb binding parameter and the polar angle were derived.
Study of the elastic scattering of {sup 6}He on {sup 208}Pb at energies around the Coulomb barrier
Energy Technology Data Exchange (ETDEWEB)
Sanchez-Benitez, A.M. [Departamento de Fisica Aplicada, Universidad de Huelva, E-21071 Huelva (Spain); Centre de Recherches du Cyclotron, Universite Catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Escrig, D. [Instituto de Estructura de la Materia, CSIC, E-28006 Madrid (Spain); Alvarez, M.A.G.; Andres, M.V. [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, E-41080 Sevilla (Spain); Angulo, C. [Centre de Recherches du Cyclotron, Universite Catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Borge, M.J.G. [Instituto de Estructura de la Materia, CSIC, E-28006 Madrid (Spain); Cabrera, J. [Centre de Recherches du Cyclotron, Universite Catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Cherubini, S. [INFN Laboratori Nazionali del Sud, I-95123 Catania (Italy); Demaret, P. [Centre de Recherches du Cyclotron, Universite Catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Espino, J.M. [Dept. de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, E-41080 Sevilla (Spain); Figuera, P. [INFN Laboratori Nazionali del Sud, I-95123 Catania (Italy); Freer, M. [School of Physics and Astronomy, University of Birmingham, B15 2TT Birmingham (United Kingdom); Garcia-Ramos, J.E. [Departamento de Fisica Aplicada, Universidad de Huelva, E-21071 Huelva (Spain); Gomez-Camacho, J. [Dept. de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, E-41080 Sevilla (Spain); Gulino, M. [INFN Laboratori Nazionali del Sud, I-95123 Catania (Italy); Kakuee, O.R. [Van der Graaff Laboratory, Nuclear Research Centre, AEOI, PO Box 14155-1339, Tehran (Iran, Islamic Republic of); Martel, I. [Dept. de Fisica Aplicada, Universidad de Huelva, E-21071 Huelva (Spain)], E-mail: imartel@uhu.es; Metelko, C. [School of Physics and Astronomy, University of Birmingham, B15 2TT Birmingham (United Kingdom); Moro, A.M. [Dept. de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, E-41080 Sevilla (Spain)] (and others)
2008-04-15
The elastic scattering of {sup 6}He on {sup 208}Pb has been measured at laboratory energies of 14, 16, 18 and 22 MeV. These data were analyzed using phenomenological Woods-Saxon form factors and optical model calculations. A semiclassical polarization potential was used to study the effect of the Coulomb dipole polarizability. Evidence for long range absorption, partially arising from Coulomb dipole polarizability, is reported. The energy variation of the optical potential was found to be consistent with the dispersion relations which connect the real and imaginary parts of the potential.
Directory of Open Access Journals (Sweden)
Юрій Олексійович Кругляк
2016-01-01
Full Text Available Coulomb blocade in singlelectronics is discussed under the «bottom – up» approach of modern nanoelectronics. The first-principle methods for calculating the charging molecular energies and charge stability diagram of the benzene molecule single-electron transistor under the Coulomb blockade regime were applied using the density-functional theory for modeling molecular properties and continuum model to describe single-electron transistor environment as well as a self-consistent approach to treat the interaction between the molecule and the environment
Directory of Open Access Journals (Sweden)
Kaoru Miura
2011-01-01
Full Text Available We have investigated the role of the Ti–O Coulomb repulsions in the appearance of the ferroelectric state in BaTiO3 as well as the role of the Zn–O Coulomb repulsions in BiZn0.5Ti0.5O3, using a first-principles calculation with optimized structures. In tetragonal BaTiO3, it is found that the Coulomb repulsions between Ti 3s and 3p states and O 2s and 2p states have an important role for the appearance of Ti ion displacement. In BiZn0.5Ti0.5O3, on the other hand, the stronger Zn–O Coulomb repulsions, which are due to the 3s, 3p, and 3d (d10 states of the Zn ion, have more important role than the Ti–O Coulomb repulsions for the appearance of the tetragonal structure. Our suggestion is consistent with the other ferroelectric perovskite oxides ABO3 in the appearance of tetragonal structures as well as rhombohedral structures.
Coulomb Correlations Intertwined with Spin and Orbital Excitations in LaCoO3
Tomiyasu, K.; Okamoto, J.; Huang, H. Y.; Chen, Z. Y.; Sinaga, E. P.; Wu, W. B.; Chu, Y. Y.; Singh, A.; Wang, R.-P.; de Groot, F. M. F.; Chainani, A.; Ishihara, S.; Chen, C. T.; Huang, D. J.
2017-11-01
We carried out temperature-dependent (20-550 K) measurements of resonant inelastic x-ray scattering on LaCoO3 to investigate the evolution of its electronic structure across the spin-state crossover. In combination with charge-transfer multiplet calculations, we accurately quantified the renomalized crystal-field excitation energies and spin-state populations. We show that the screening of the effective on-site Coulomb interaction of 3 d electrons is orbital selective and coupled to the spin-state crossover in LaCoO3 . The results establish that the gradual spin-state crossover is associated with a relative change of Coulomb energy versus bandwidth, leading to a Mott-type insulator-to-metal transition.
Direct and resonant breakup of {sup 6}He on {sup 209}Bi near the Coulomb barrier
Energy Technology Data Exchange (ETDEWEB)
Kolata, J.J. [Physics Department, University of Notre Dame, Notre Dame, Indiana, 46556-5670 (United States)
2007-12-15
As part of a program to study reactions induced by the two-neutron halo nucleus {sup 6}He on high-Z targets, a neutron-{alpha} particle coincidence experiment was performed for {sup 6}He incident on a {sup 209}Bi target at an energy just above the Coulomb barrier. The experimental setup was optimized for the measurement of projectile breakup. Direct breakup, as well as breakup through the 2{sup +} excited state of {sup 6}He and also the {sup 5}He+n channel, could be distinguished. The total breakup cross section measured in this work compares well with a continuum-discretized coupled-channels calculation that assumes a 50% reduction in the B(E1) computed from a pure {sup 4}He+2n cluster configuration. The B(E2{up_arrow}) for Coulomb excitation of the 2{sup +} state in {sup 6}He was also determined. (Author)
Coulomb excitation of the two proton-hole nucleus $^{206}$Hg
We propose to use Coulomb excitation of the single magic two-proton-hole nucleus $^{206}$Hg. In a single-step excitation both the first 2$^{+}$ and the highly collective octupole 3$^{-}$ states will be populated. Thus, information on both quadrupole and octupole collectivity will be gained in this neutron-rich nucleus. Due to the high beam intensity, we will be able to observe multi-step Coulomb excitation as well, providing further test on theoretical calculations. The results will be used to improve the predictive power of the shell model for more exotic nuclei as we move to lighter N=126 nuclei. The experiment will use the new HIE-ISOLDE facility and the MINIBALL array, and will take advantage of the recently developed $^{206}$Hg beam from the molten lead target.
Study of the neutron rich sulfure isotope 43S through intermediate energy Coulomb excitation
Calinescu, S.; Cáceres, L.; Grévy, S.; Sohler, D.; Stanoiu, M.; Negoita, F.; Borcea, C.; Borcea, R.; Bowry, M.; Catford, W.; Dombradi, Z.; Franchoo, S.; Gillibert, R.; Thomas, J. C.; Kuti, I.; Lukyanov, S.; Lepailleur, A.; Mrazek, J.; Niikura, M.; Podolyak, Z.; Petrone, C.; Penionzhkevich, Y.; Roger, T.; Rotaru, F.; Sorlin, O.; Stefan, I.; Vajta, Z.; Wilson, E.
2013-02-01
The reduced transition probability B(E2: 3/2- 7/2-2) has been measured in 43S using Coulomb excitation at intermediate energy. The nucleus of interest was produced by fragmentation of a 48Ca beam at GANIL. The reaction products were separated in the LISE spectrometer. After Coulomb-excitation of 43S in a 208Pb target, the γ rays emitted inflight were detected by 64 BaF2 detectors of the Chǎteau de Cristal array. The preliminary value deduced for the reduced transition probability B(E2: 3/2-7/2-2) is in agreement with the predictions of the shell model calculations and supports a prolate-spherical shape coexistence in the 43S nucleus.
Thermoelectrics in Coulomb-coupled quantum dots: Cotunneling and energy-dependent lead couplings
Walldorf, Nicklas; Jauho, Antti-Pekka; Kaasbjerg, Kristen
2017-09-01
We study thermoelectric effects in Coulomb-coupled quantum-dot (CCQD) systems beyond lowest-order tunneling processes and the often applied wide-band approximation. To this end, we present a master-equation (ME) approach based on a perturbative T -matrix calculation of the charge and heat tunneling rates and transport currents. Applying the method to transport through a noninteracting single-level QD, we demonstrate excellent agreement with the Landauer-Büttiker theory when higher-order (cotunneling) processes are included in the ME. Next, we study the effect of cotunneling and energy-dependent lead couplings on the heat currents in a system of two CCQDs. We find that cotunneling processes (i) can dominate the off-resonant heat currents at low temperature and bias compared to the interdot interaction, and (ii) give rise to a pronounced reduction of the cooling power achievable with the recently demonstrated Maxwell's demon cooling mechanism. Furthermore, we demonstrate that the cooling power can be boosted significantly by carefully engineering the energy dependence of the lead couplings to filter out undesired transport processes. Our findings emphasize the importance of higher-order cotunneling processes as well as engineered energy-dependent lead couplings in the optimization of the thermoelectric performance of CCQD systems.
Modeling the self-similarity in complex networks based on Coulomb's law
Zhang, Haixin; Wei, Daijun; Hu, Yong; Lan, Xin; Deng, Yong
2016-06-01
Recently, self-similarity of complex networks have attracted much attention. Fractal dimension of complex network is an open issue. Hub repulsion plays an important role in fractal topologies. This paper models the repulsion among the nodes in the complex networks in calculation of the fractal dimension of the networks. Coulomb's law is adopted to represent the repulse between two nodes of the network quantitatively. A new method to calculate the fractal dimension of complex networks is proposed. The Sierpinski triangle network and some real complex networks are investigated. The results are illustrated to show that the new model of self-similarity of complex networks is reasonable and efficient.
Spectral broadening due to long-range Coulomb interactions in the molecular metal TTF-TCNQ
Energy Technology Data Exchange (ETDEWEB)
Koch, E.; Dolfen, A. [Inst. fuer Festkoerperforschung, Forschungszentrum Juelich (Germany); Cano-Cortes, L.; Merino, J. [Univ. Autonona de Madrid (Spain); Behler, J.; Reuter, K. [Fritz-Haber-Inst., Berlin (Germany); Delley, B. [Paul-Scherrer-Inst., Villigen (Switzerland)
2007-07-01
We employ density-functional theory to calculate realistic parameters for an extended Hubbard model of the molecular metal TTF-TCNQ. Considering both intra- and intermolecular screening in the crystal, we find that longer-range Coulomb interactions along the molecular stacks, as well as inter-stack coupling are of importance. Contrary to past belief, these terms do not lead to the formation of a Wigner lattice, but simply broaden the spectral function. We show how this can be understood already in perturbation theory. Moreover we calculate the effect of the nearest neighbor repulsion on the Luttinger parameter. (orig.)
On the Emergence of the Coulomb Forces in Quantum Electrodynamics
Directory of Open Access Journals (Sweden)
Jan Naudts
2017-01-01
Full Text Available A simple transformation of field variables eliminates Coulomb forces from the theory of quantum electrodynamics. This suggests that Coulomb forces may be an emergent phenomenon rather than being fundamental. This possibility is investigated in the context of reducible quantum electrodynamics. It is shown that states exist which bind free photon and free electron fields. The binding energy peaks in the long-wavelength limit. This makes it plausible that Coulomb forces result from the interaction of the electron/positron field with long-wavelength transversely polarized photons.
Coulomb implosion mechanism of negative ion acceleration in laser plasmas
Energy Technology Data Exchange (ETDEWEB)
Nakamura, T., E-mail: nakamura.tatsufumi@jaea.go.j [Kansai Photon Science Institute (JAEA), 8-1 Umemidai, Kizugawa, Kyoto 619-0215 (Japan); Fukuda, Y.; Yogo, A.; Tampo, M.; Kando, M.; Hayashi, Y.; Kameshima, T.; Pirozhkov, A.S.; Esirkepov, T.Zh.; Pikuz, T.A.; Faenov, A.Ya.; Daido, H.; Bulanov, S.V. [Kansai Photon Science Institute (JAEA), 8-1 Umemidai, Kizugawa, Kyoto 619-0215 (Japan)
2009-07-06
Coulomb implosion mechanism of the negatively charged ion acceleration in laser plasmas is proposed. When a cluster target is irradiated by an intense laser pulse and the Coulomb explosion of positively charged ions occurs, the negative ions are accelerated inward. The maximum energy of negative ions is several times lower than that of positive ions. We present the theoretical description and Particle-in-Cell simulation results of the Coulomb implosion mechanism, and show the evidence of the negative ion acceleration in the experiments on the high intensity laser pulse interaction with the cluster targets.
Relativistic Coulomb excitation of {sup 88}Kr
Energy Technology Data Exchange (ETDEWEB)
Moschner, Kevin; Blazhev, Andrey; Jolie, Jan; Warr, Nigel; Wendt, Andreas [IKP, Universitaet zu Koeln, 50937 Koeln (Germany); Collaboration: PreSPEC-Collaboration
2015-07-01
Within the scope of the PreSPEC campaign we performed a Coulomb-excitation experiment to determine absolute E2 transition strengths to 2{sup +} states in the radioactive nucleus {sup 88}Kr. The aim of our studies was to identify the one quadruple-phonon mixed-symmetry 2{sub MS}{sup +} state in order to extend our knowledge on these states to lighter N = 52 isotones and to track their evolution over different proton shells. The investigated ions were provided through projectile fission of a 650 MeV {sup 238}U beam on a primary target consisting of 0.6 g/cm{sup 2} {sup 9}Be and subsequent separation and identification of the reaction products via the FRS at GSI. The secondary target consisted of 0.4 g/cm{sup 2} {sup 197}Au. De-exciting γ radiation was detected by the PreSPEC array, consisting of 15 EUROBALL Cluster detectors. The Lund-York-Cologne-CAlorimeter LYCCA was used for particle identification after the secondary target. Absolute transition strengths of the transitions depopulating the 2{sup +}{sub 3} state in {sup 88}Kr which suggest the mixed symmetric character of this state are presented and discussed within the systematics of the N = 52 isotones.
Correlation functions of Coulomb branch operators
Energy Technology Data Exchange (ETDEWEB)
Gerchkovitz, Efrat [Weizmann Institute of Science,Rehovot 76100 (Israel); Gomis, Jaume [Perimeter Institute for Theoretical Physics,Waterloo, ON N2L 2Y5 (Canada); Ishtiaque, Nafiz [Perimeter Institute for Theoretical Physics,Waterloo, ON N2L 2Y5 (Canada); Department of Physics, University of Waterloo,Waterloo, ON N2L 3G1 (Canada); Karasik, Avner; Komargodski, Zohar [Weizmann Institute of Science,Rehovot 76100 (Israel); Pufu, Silviu S. [Joseph Henry Laboratories, Princeton University,Princeton, NJ 08544 (United States)
2017-01-24
We consider the correlation functions of Coulomb branch operators in four-dimensional N=2 Superconformal Field Theories (SCFTs) involving exactly one anti-chiral operator. These extremal correlators are the “minimal' non-holomorphic local observables in the theory. We show that they can be expressed in terms of certain determinants of derivatives of the four-sphere partition function of an appropriate deformation of the SCFT. This relation between the extremal correlators and the deformed four-sphere partition function is non-trivial due to the presence of conformal anomalies, which lead to operator mixing on the sphere. Evaluating the deformed four-sphere partition function using supersymmetric localization, we compute the extremal correlators explicitly in many interesting examples. Additionally, the representation of the extremal correlators mentioned above leads to a system of integrable differential equations. We compare our exact results with previous perturbative computations and with the four-dimensional tt{sup ∗} equations. We also use our results to study some of the asymptotic properties of the perturbative series expansions we obtain in N=2 SQCD.
Accelerated Monte Carlo Methods for Coulomb Collisions
Rosin, Mark; Ricketson, Lee; Dimits, Andris; Caflisch, Russel; Cohen, Bruce
2014-03-01
We present a new highly efficient multi-level Monte Carlo (MLMC) simulation algorithm for Coulomb collisions in a plasma. The scheme, initially developed and used successfully for applications in financial mathematics, is applied here to kinetic plasmas for the first time. The method is based on a Langevin treatment of the Landau-Fokker-Planck equation and has a rich history derived from the works of Einstein and Chandrasekhar. The MLMC scheme successfully reduces the computational cost of achieving an RMS error ɛ in the numerical solution to collisional plasma problems from (ɛ-3) - for the standard state-of-the-art Langevin and binary collision algorithms - to a theoretically optimal (ɛ-2) scaling, when used in conjunction with an underlying Milstein discretization to the Langevin equation. In the test case presented here, the method accelerates simulations by factors of up to 100. We summarize the scheme, present some tricks for improving its efficiency yet further, and discuss the method's range of applicability. Work performed for US DOE by LLNL under contract DE-AC52- 07NA27344 and by UCLA under grant DE-FG02-05ER25710.
Coulomb gas partition function of a layered loop model
Energy Technology Data Exchange (ETDEWEB)
Shimada, Hirohiko, E-mail: shimada@dice.c.u-tokyo.ac.j [Department of Basic Sciences, University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo 153-8902 (Japan)
2010-12-03
We consider a two-dimensional bi-layered loop model with a certain interlayer coupling and study its spectrum on a torus. Each layer consists of an O(n) model on a honeycomb lattice with periodic boundary conditions; these layers are stacked such that the links of the lattice intersect each other. A complex Boltzmann weight {lambda} with unit modulus is assigned to each intersection of two loops each from each layer. The model is reduced to an inhomogeneous vertex model at a special point of parameters. The continuum partition function is represented, based on the idea of the Coulomb gas, by a path integral over two compact bosonic fields. The modular invariance of the partition function follows naturally. Further, because of the topological nature of the interlayer coupling, the fluctuation of loops decomposes into a local and a global part. The existence of the latter leads to a sum over all the pairs of torus knots, which can be Poisson resummed by the Moebius inversion formula. This reveals the operator content of the theory. The multiplicity of each operator is explicitly given by a combination of two Ramanujan sums. We calculate each scaling dimension as a function of {lambda}. We present the flow of dimensions which connects the decoupled-O(1) models at {lambda} = 1 and the layered-O(1) model with the non-trivial coupling {lambda} = -1. The lower spectrum in the latter model is related to that of a known coset model.
Coulomb gas partition function of a layered loop model
Shimada, Hirohiko
2010-12-01
We consider a two-dimensional bi-layered loop model with a certain interlayer coupling and study its spectrum on a torus. Each layer consists of an O(n) model on a honeycomb lattice with periodic boundary conditions; these layers are stacked such that the links of the lattice intersect each other. A complex Boltzmann weight λ with unit modulus is assigned to each intersection of two loops each from each layer. The model is reduced to an inhomogeneous vertex model at a special point of parameters. The continuum partition function is represented, based on the idea of the Coulomb gas, by a path integral over two compact bosonic fields. The modular invariance of the partition function follows naturally. Further, because of the topological nature of the interlayer coupling, the fluctuation of loops decomposes into a local and a global part. The existence of the latter leads to a sum over all the pairs of torus knots, which can be Poisson resummed by the Möbius inversion formula. This reveals the operator content of the theory. The multiplicity of each operator is explicitly given by a combination of two Ramanujan sums. We calculate each scaling dimension as a function of λ. We present the flow of dimensions which connects the decoupled-O(1) models at λ = 1 and the layered-O(1) model with the non-trivial coupling λ = -1. The lower spectrum in the latter model is related to that of a known coset model.
Energy Technology Data Exchange (ETDEWEB)
Turrell, A.E., E-mail: a.turrell09@imperial.ac.uk; Sherlock, M.; Rose, S.J.
2015-10-15
Large-angle Coulomb collisions allow for the exchange of a significant proportion of the energy of a particle in a single collision, but are not included in models of plasmas based on fluids, the Vlasov–Fokker–Planck equation, or currently available plasma Monte Carlo techniques. Their unique effects include the creation of fast ‘knock-on’ ions, which may be more likely to undergo certain reactions, and distortions to ion distribution functions relative to what is predicted by small-angle collision only theories. We present a computational method which uses Monte Carlo techniques to include the effects of large-angle Coulomb collisions in plasmas and which self-consistently evolves distribution functions according to the creation of knock-on ions of any generation. The method is used to demonstrate ion distribution function distortions in an inertial confinement fusion (ICF) relevant scenario of the slowing of fusion products.
Analysis and results of the 104Sn Coulomb excitation experiment
Guastalla, G.; DiJulio, D. D.; Górska, M.; Cederkäll, J.; Boutachkov, P.; Golubev, P.; Pietri, S.; Grawe, H.; Nowacki, F.; Algora, A.; Ameil, F.; Arici, T.; Atac, A.; Bentley, M. A.; Blazhev, A.; Bloor, D.; Brambilla, S.; Braun, N.; Camera, F.; Domingo Pardo, C.; Estrade, A.; Farinon, F.; Gerl, J.; Goel, N.; Grȩbosz, J.; Habermann, T.; Hoischen, R.; Jansson, K.; Jolie, J.; Jungclaus, A.; Kojouharov, I.; Knoebel, R.; Kumar, R.; Kurcewicz, J.; Kurz, N.; Lalović, N.; Merchan, E.; Moschner, K.; Naqvi, F.; Nara Singh, B. S.; Nyberg, J.; Nociforo, C.; Obertelli, A.; Pfützner, M.; Pietralla, N.; Podolyák, Z.; Prochazka, A.; Ralet, D.; Reiter, P.; Rudolph, D.; Schaffner, H.; Schirru, F.; Scruton, L.; Swaleh, T.; Taprogge, J.; Wadsworth, R.; Warr, N.; Weick, H.; Wendt, A.; Wieland, O.; Winfield, J. S.; Wollersheim, H. J.
2014-09-01
The analysis of the Coulomb excitation experiment conducted on 104Sn required a strict selection of the data in order to reduce the large background present in the γ-ray energy spectra and identify the γ-ray peak corresponding to the Coulomb excitation events. As a result the B(E2; 0+ → 2+) value could be extracted, which established the downward trend towards 100Sn and therefore the robustness of the N=Z=50 core against quadrupole excitations.
Optically induced structural phase transitions in ion Coulomb crystals
DEFF Research Database (Denmark)
Horak, Peter; Dantan, Aurelien Romain; Drewsen, Michael
2012-01-01
We investigate numerically the structural dynamics of ion Coulomb crystals confined in a three-dimensional harmonic trap when influenced by an additional one-dimensional optically induced periodical potential. We demonstrate that transitions between thermally excited crystal structures, such as b......We investigate numerically the structural dynamics of ion Coulomb crystals confined in a three-dimensional harmonic trap when influenced by an additional one-dimensional optically induced periodical potential. We demonstrate that transitions between thermally excited crystal structures...
Xie, Hong-Yi; Foster, Matthew S.
2016-05-01
We study the electric and thermal transport of the Dirac carriers in monolayer graphene using the Boltzmann-equation approach. Motivated by recent thermopower measurements [F. Ghahari, H.-Y. Xie, T. Taniguchi, K. Watanabe, M. S. Foster, and P. Kim, Phys. Rev. Lett. 116, 136802 (2016), 10.1103/PhysRevLett.116.136802], we consider the effects of quenched disorder, Coulomb interactions, and electron-optical-phonon scattering. Via an unbiased numerical solution to the Boltzmann equation we calculate the electrical conductivity, thermopower, and electronic component of the thermal conductivity, and discuss the validity of Mott's formula and of the Wiedemann-Franz law. An analytical solution for the disorder-only case shows that screened Coulomb impurity scattering, although elastic, violates the Wiedemann-Franz law even at low temperature. For the combination of carrier-carrier Coulomb and short-ranged impurity scattering, we observe the crossover from the interaction-limited (hydrodynamic) regime to the disorder-limited (Fermi-liquid) regime. In the former, the thermopower and the thermal conductivity follow the results anticipated by the relativistic hydrodynamic theory. On the other hand, we find that optical phonons become non-negligible at relatively low temperatures and that the induced electron thermopower violates Mott's formula. Combining all of these scattering mechanisms, we obtain the thermopower that quantitatively coincides with the experimental data.
Testing refined shell-model interactions in the sd shell: Coulomb excitation of Na26
Siebeck, B; Blazhev, A; Reiter, P; Altenkirch, R; Bauer, C; Butler, P A; De Witte, H; Elseviers, J; Gaffney, L P; Hess, H; Huyse, M; Kröll, T; Lutter, R; Pakarinen, J; Pietralla, N; Radeck, F; Scheck, M; Schneiders, D; Sotty, C; Van Duppen, P; Vermeulen, M; Voulot, D; Warr, N; Wenander, F
2015-01-01
Background: Shell-model calculations crucially depend on the residual interaction used to approximate the nucleon-nucleon interaction. Recent improvements to the empirical universal sd interaction (USD) describing nuclei within the sd shell yielded two new interactions—USDA and USDB—causing changes in the theoretical description of these nuclei. Purpose: Transition matrix elements between excited states provide an excellent probe to examine the underlying shell structure. These observables provide a stringent test for the newly derived interactions. The nucleus Na26 with 7 valence neutrons and 3 valence protons outside the doubly-magic 16O core is used as a test case. Method: A radioactive beam experiment with Na26 (T1/2=1,07s) was performed at the REX-ISOLDE facility (CERN) using Coulomb excitation at safe energies below the Coulomb barrier. Scattered particles were detected with an annular Si detector in coincidence with γ rays observed by the segmented MINIBALL array. Coulomb excitation cross sections...
Renormalization of Coulomb interactions in a system of two-dimensional tilted Dirac fermions
Lee, Yu-Wen; Lee, Yu-Li
2018-01-01
We investigate the effects of long-ranged Coulomb interactions in a tilted Dirac semimetal in two dimensions by using the perturbative renormalization-group (RG) method. Depending on the magnitude of the tilting parameter, the undoped system can have either Fermi points (type I) or Fermi lines (type II). Previous studies usually performed the renormalization-group transformations by integrating out the modes with large momenta. This is problematic when the Fermi surface is open, like type-II Dirac fermions. In this work we study the effects of Coulomb interactions, following the spirit of Shankar [Rev. Mod. Phys. 66, 129 (1994), 10.1103/RevModPhys.66.129], by introducing a cutoff in the energy scale around the Fermi surface and integrating out the high-energy modes. For type-I Dirac fermions, our result is consistent with that of the previous work. On the other hand, we find that for type-II Dirac fermions, the magnitude of the tilting parameter increases monotonically with lowering energies. This implies the stability of type-II Dirac fermions in the presence of Coulomb interactions, in contrast with previous results. Furthermore, for type-II Dirac fermions, the velocities in different directions acquire different renormalization even if they have the same bare values. By taking into account the renormalization of the tilting parameter and the velocities due to the Coulomb interactions, we show that while the presence of a charged impurity leads only to charge redistribution around the impurity for type-I Dirac fermions, for type-II Dirac fermions, the impurity charge is completely screened, albeit with a very long screening length. The latter indicates that the temperature dependence of physical observables are essentially determined by the RG equations we derived. We illustrate this by calculating the temperature dependence of the compressibility and specific heat of the interacting tilted Dirac fermions.
Charged colloids, polyelectrolytes and biomolecules viewed as strongly coupled Coulomb systems
Löwen, H; Likos, C N; Blaak, R; Dzubiella, J; Jusufi, A; Hoffmann, N; Harreis, H M
2003-01-01
A brief review is given on recent studies of charged soft matter solutions, as modelled by the 'primitive' approach of strongly coupled Coulomb systems, where the solvent just enters as a dielectric background. These include charged colloids, biological macromolecules such as proteins and DNA, polyelectrolytes and polyelectrolyte stars. Also some original results are presented on colloid-polyelectrolyte complex formation near walls and on the anomalous fluid structure of polyelectrolyte stars as a function of increasing concentration.
Fusion and Direct Reactions of Halo Nuclei at Energies around the Coulomb Barrier
Keeley, N; Raabe, R; Sida, J L
2007-01-01
The present understanding of reaction processes involving light unstable nuclei at energies around the Coulomb barrier is reviewed. The effect of coupling to direct reaction channels on elastic scattering and fusion is investigated, with the focus on halo nuclei. A list of definitions of processes is given, followed by a review of the experimental and theoretical tools and information presently available. The effect of couplings on elastic scattering and fusion is studied with a series of model calculations within the coupled-channels framework. The experimental data on fusion are compared to "bare" no-coupling one-dimensional barrier penetration model calculations. On the basis of these calculations and comparisons with experimental data, conclusions are drawn from the observation of recurring features. The total fusion cross sections for halo nuclei show a suppression with respect to the "bare" calculations at energies just above the barrier that is probably due to single neutron transfer reactions. The dat...
Relativistic two-body Coulomb-Breit Hamiltonian in an external weak gravitational field
Caicedo, J. A.; Urrutia, L. F.
2011-11-01
A construction of the Coulomb-Breit Hamiltonian for a pair of fermions, considered as a quantum two-body system, immersed in an arbitrary background gravitational field described by Einstein's General Relativity is presented. Working with Fermi normal coordinates for a freely falling observer in a spacetime region where there are no background sources and ignoring the gravitational back-reaction of the system, the effective Coulomb-Breit Hamiltonian is obtained starting from the S-matrix element corresponding to the one-photon exchange between the charged fermionic currents. The contributions due to retardation are considered up to order (v / c) 2 and they are subsequently written as effective operators in the relativistic quantum mechanical Hilbert space of the system. The final Hamiltonian includes effects linear in the curvature and up to order (v / c) 2.
Relativistic two-body Coulomb-Breit Hamiltonian in an external weak gravitational field
Energy Technology Data Exchange (ETDEWEB)
Caicedo, J.A. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A. Postal 70-543, 04510 Mexico D.F. (Mexico); Urrutia, L.F., E-mail: urrutia@nucleares.unam.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A. Postal 70-543, 04510 Mexico D.F. (Mexico)
2011-11-03
A construction of the Coulomb-Breit Hamiltonian for a pair of fermions, considered as a quantum two-body system, immersed in an arbitrary background gravitational field described by Einstein's General Relativity is presented. Working with Fermi normal coordinates for a freely falling observer in a spacetime region where there are no background sources and ignoring the gravitational back-reaction of the system, the effective Coulomb-Breit Hamiltonian is obtained starting from the S-matrix element corresponding to the one-photon exchange between the charged fermionic currents. The contributions due to retardation are considered up to order (v/c){sup 2} and they are subsequently written as effective operators in the relativistic quantum mechanical Hilbert space of the system. The final Hamiltonian includes effects linear in the curvature and up to order (v/c){sup 2}.
Onset of collectivity in $^{96,98}$Sr studied via Coulomb excitation
Clement, E; Dijon, A; de France, G; Bastin, B; Blazhev, A; Bree, N; Butler, P; Delahaye, P; Ekstrom, A; Georgiev, G; Hasan, N; Iwanicki, J; Jenkins, D; Korten, W; Larsen, A C; Ljungvall, J; Moschner, K; Napiorkowski, P; Pakarinen, J; Petts, A; Renstrom, T; Seidlitz, M; Siem, S; Sotty, C; Srebrny, J; Stefanescu, I; Tveten, G M; Van de Walle, J; Warr, N; Wrzosek-Lipska, K; Zielinska, M; Bauer, C; Bruyneel, B; Butterworth, J; Fitzpatrick, C; Fransen, C; GernhäUser, R; Hess, H; Lutter, R; Marley, P; Reiter, P; Siebeck, B; Vermeulen, M; Wiens, A; De Witte, H
2014-01-01
A rapid onset of quadrupole deformation is known to occur around the neutron number 60 in the neutron-rich Zr and Sr isotopes. This shape change has made the neutron-rich A = 100 region an active area of experimental and theoretical studies for many decades now. We report in this contribution new experimental results in the neutron rich 96,98Sr investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility, CERN. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross section supporting the scenario of shape coexistence/change at N=60. Future perspectives are presented including the recent experimental campaign performed at ILL-Grenoble.
Coulomb excitation of neutron-rich $^{134-136}$Sn isotopes
We propose to study excited states in the isotopes $^{134,136}$Sn by $\\gamma$-ray spectroscopy following "safe" Coulomb excitation. The experiment aims to investigate the evolution of quadrupole collectivity beyond the magic shell closure at N = 82 by the determination of B(E2) values and electric quadrupole moments $\\mathcal{Q}_2$. Recent shell-model calculations using realistic interactions predict possible enhanced collectivity in neutron-rich regions. Evidence for this could be obtained by this experiment. Furthermore, the currently unknown excitation energies of the 2$^+_{1}$ and 4$^+_{1}$ states in $^{136}$Sn will be measured for the first time.
Efficient Modeling of Coulomb Interaction Effect on Exciton in Crystal-Phase Nanowire Quantum Dot
DEFF Research Database (Denmark)
Taherkhani, Masoomeh; Gregersen, Niels; Mørk, Jesper
2016-01-01
The binding energy and oscillation strength of the ground-state exciton in type-II quantum dot (QD) is calculated by using a post Hartree-Fock method known as the configuration interaction (CI) method which is significantly more efficient than conventional methods like ab initio method. We show t...... that the Coulomb interaction between electron and holes in these structures considerably affects the transition dipole moment which is the key parameter of optical quantum gating in STIRAP (stimulated Raman adiabatic passage) process for implementing quantum gates [1], [2]....
Analytic quantum-interference conditions in Coulomb corrected photoelectron holography
Maxwell, A. S.; Al-Jawahiry, A.; Lai, X. Y.; Figueira de Morisson Faria, C.
2018-02-01
We provide approximate analytic expressions for above-threshold ionization (ATI) transition probabilities and photoelectron angular distributions. These analytic expressions are more general than those existing in the literature and include the residual binding potential in the electron continuum propagation. They successfully reproduce the ATI side lobes and specific holographic structures such as the near-threshold fan-shaped pattern and the spider-like structure that extends up to relatively high photoelectron energies. We compare such expressions with the Coulomb quantum orbit strong-field approximation (CQSFA) and the full solution of the time-dependent Schrödinger equation for different driving-field frequencies and intensities, and provide an in-depth analysis of the physical mechanisms behind specific holographic structures. Our results shed additional light on what aspects of the CQSFA must be prioritized in order to obtain the key holographic features, and highlight the importance of forward scattered trajectories. Furthermore, we find that the holographic patterns change considerably for different field parameters, even if the Keldysh parameter is kept roughly the same.
The secondary supernova machine: Gravitational compression, stored Coulomb energy, and SNII displays
Clayton, Donald D.; Meyer, Bradley S.
2016-04-01
Radioactive power for several delayed optical displays of core-collapse supernovae is commonly described as having been provided by decays of 56Ni nuclei. This review analyses the provenance of that energy more deeply: the form in which that energy is stored; what mechanical work causes its storage; what conservation laws demand that it be stored; and why its release is fortuitously delayed for about 106 s into a greatly expanded supernova envelope. We call the unifying picture of those energy transfers the secondary supernova machine owing to its machine-like properties; namely, mechanical work forces storage of large increases of nuclear Coulomb energy, a positive energy component within new nuclei synthesized by the secondary machine. That positive-energy increase occurs despite the fusion decreasing negative total energy within nuclei. The excess of the Coulomb energy can later be radiated, accounting for the intense radioactivity in supernovae. Detailed familiarity with this machine is the focus of this review. The stored positive-energy component created by the machine will not be reduced until roughly 106 s later by radioactive emissions (EC and β +) owing to the slowness of weak decays. The delayed energy provided by the secondary supernova machine is a few × 1049 erg, much smaller than the one percent of the 1053 erg collapse that causes the prompt ejection of matter; however, that relatively small stored energy is vital for activation of the late displays. The conceptual basis of the secondary supernova machine provides a new framework for understanding the energy source for late SNII displays. We demonstrate the nuclear dynamics with nuclear network abundance calculations, with a model of sudden compression and reexpansion of the nuclear gas, and with nuclear energy decompositions of a nuclear-mass law. These tools identify excess Coulomb energy, a positive-energy component of the total negative nuclear energy, as the late activation energy. If the
Coulomb branch Hilbert series and Hall-Littlewood polynomials
Cremonesi, Stefano; Mekareeya, Noppadol; Zaffaroni, Alberto
2014-01-01
There has been a recent progress in understanding the chiral ring of 3d $\\mathcal{N}=4$ superconformal gauge theories by explicitly constructing an exact generating function (Hilbert series) counting BPS operators on the Coulomb branch. In this paper we introduce Coulomb branch Hilbert series in the presence of background magnetic charges for flavor symmetries, which are useful for computing the Hilbert series of more general theories through gluing techniques. We find a simple formula of the Hilbert series with background magnetic charges for $T_\\rho(G)$ theories in terms of Hall-Littlewood polynomials. Here $G$ is a classical group and $\\rho$ is a certain partition related to the dual group of $G$. The Hilbert series for vanishing background magnetic charges show that Coulomb branches of $T_\\rho(G)$ theories are complete intersections. We also demonstrate that mirror symmetry maps background magnetic charges to baryonic charges.
Use of Prandtl-Ishlinskii hysteresis operators for Coulomb friction modeling with presliding
Ruderman, Michael; Rachinskii, Dmitrii
2017-02-01
Prandtl-Ishlinskii stop-type hysteresis operators allow for modeling elasto-plasticity in the relative stress-strain coordinates including the saturation level of the residual constant-tension flow. This lies in direct equivalence to the force-displacement characteristics of nonlinear Coulomb friction, whose constant average value at unidirectional motion depends on the motion sign only, after the transient presliding phase at each motion reversal. In this work, we analyze and demonstrate the use of Prandtl-Ishlinskii operators for modeling the Coulomb friction with presliding phase. No viscous i.e. velocity-dependent component is considered at this stage, and the constant damping rate of the Coulomb friction is combined with the rate-independent losses of presliding hysteresis. The general case of Prandtl-Ishlinskii operator with a continuous distribution function is considered together with a finite elements case, which is useful for implementation in multiple applications. Finally, identification of parameters is addressed and discussed along with two experimental examples.
Lipparini, Filippo; Gauss, Jürgen
2016-09-13
We present an implementation of the complete active space-self-consistent field (CASSCF) method specifically designed to be used in four-component scalar relativistic calculations based on the spin-free Dirac-Coulomb (SFDC) Hamiltonian. Our implementation takes full advantage of the properties of the SFDC Hamiltonian that allow us to use real algebra and to exploit point-group and spin symmetry to their full extent while including in a rigorous way scalar relativistic effects in the treatment. The SFDC-CASSCF treatment is more expensive than its non-relativistic counterpart only in the orbital optimization step, while exhibiting the same computational cost for the rate-determining full configuration interaction part. The numerical aspects are discussed, and the capabilities of the SFDC-CASSCF methodology are demonstrated through a pilot application.
Hoffmann, Scott E.
2017-11-01
We calculate the nonrelativistic scattering of a wavepacket from a Coulomb potential and find deviations from the Rutherford formula in all cases. These generally occur only at low scattering angles, where they would be obscured by the part of the incident beam that emerges essentially unscattered. For a model experiment, the scattering of helium nuclei from a thin gold foil, we find the deviation region is magnified for low incident energies (in the keV range), so that a large shadow zone of low probability around the forward direction is expected to be measurable. From a theoretical perspective, the use of wavepackets makes partial wave analysis applicable to this infinite-range potential. It allows us to calculate the everywhere finite probability for a wavepacket to wavepacket transition and to relate this to the differential cross section. Time delays and advancements in the detection probabilities can be calculated. We investigate the optical theorem as applied to this special case.
A study of the evolution of the nuclear structure along the zinc isotopic chain close to the doubly magic nucleus $^{78}$Ni is proposed to probe recent shell-model calculations in this area of the nuclear chart. Excitation energies and connecting B(E2) values will be measured through multiple Coulomb excitation experiment with laser ionized purified beams of $^{74-80}$Zn from HIE ISOLDE. The current proposal request 30 shifts.
Vibrational motions in rotating nuclei studied by Coulomb excitations
Energy Technology Data Exchange (ETDEWEB)
Shimizu, Yoshifumi R. [Kyushu Univ., Fukuoka (Japan). Dept. of Physics
1998-03-01
As is well-known Coulomb excitation is an excellent tool to study the nuclear collective motions. Especially the vibrational excitations in rotating nuclei, which are rather difficult to access by usual heavy-ion fusion reactions, can be investigated in detail. Combined with the famous 8{pi}-Spectrometer, which was one of the best {gamma}-ray detector and had discovered some of superdeformed bands, such Coulomb excitation experiments had been carried out at Chalk River laboratory just before it`s shutdown of physics division. In this meeting some of the experimental data are presented and compared with the results of theoretical investigations. (author)
The structure of low-lying states in ${}^{140}$Sm studied by Coulomb excitation
Klintefjord, M.; Görgen, A.; Bauer, C.; Bello Garrote, F.L.; Bönig, S.; Bounthong, B.; Damyanova, A.; Delaroche, J.P.; Fedosseev, V.; Fink, D.A.; Giacoppo, F.; Girod, M.; Hoff, P.; Imai, N.; Korten, W.; Larsen, A.C.; Libert, J.; Lutter, R.; Marsh, B.A.; Molkanov, P.L.; Naïdja, H.; Napiorkowski, P.; Nowacki, F.; Pakarinen, J.; Rapisarda, E.; Reiter, P.; Renstrøm, T.; Rothe, S.; Seliverstov, M.D.; Siebeck, B.; Siem, S.; Srebrny, J.; Stora, T.; Thöle, P.; Tornyi, T.G.; Tveten, G.M.; Van Duppen, P.; Vermeulen, M.J.; Voulot, D.; Warr, N.; Wenander, F.; De Witte, H.; Zielińska, M.
2016-05-02
The electromagnetic structure of $^{140}$Sm was studied in a low-energy Coulomb excitation experiment with a radioactive ion beam from the REX-ISOLDE facility at CERN. The $2^+$ and $4^+$ states of the ground-state band and a second $2^+$ state were populated by multi-step excitation. The analysis of the differential Coulomb excitation cross sections yielded reduced transition probabilities between all observed states and the spectroscopic quadrupole moment for the $2_1^+$ state. The experimental results are compared to large-scale shell model calculations and beyond-mean-field calculations based on the Gogny D1S interaction with a five-dimensional collective Hamiltonian formalism. Simpler geometric and algebraic models are also employed to interpret the experimental data. The results indicate that $^{140}$Sm shows considerable $\\gamma$ softness, but in contrast to earlier speculation no signs of shape coexistence at low excitation energy. This work sheds more light on the onset of deformation and collectivit...
Coulomb excitation of neutron-rich odd-$A$ Cd isotopes
Reiter, P; Kruecken, R; Gernhaeuser, R A; Kroell, T; Leske, J; Marginean, N M
We propose to study excited states in the odd-${A}$ isotopes $^{123,125,127}$Cd by ${\\gamma}$-ray spectroscopy following "safe" Coulomb excitation. The experiment aims to determine the B(E2) values connecting excited states with the ground state as well as the long-lived (11/2$^{-}$) isomer. The proposed study profits from the unique capability of ISOLDE to produce beams containing Cd in the ground state or in the isomeric state. Our recent results on the neutron-rich even-A Cd nuclei appear to show that these nuclei may possess some collectivity beyond that calculated by modern shell-model predictions. Beyond-mean-field calculations also predict these nuclei to be weakly deformed. These facets are surprising considering their proximity to the doubly magic $^{132}$Sn. Coulomb-excitation studies of odd-${A}$ Cd isotopes may give a unique insight into the deformation-driving roles played by different orbits in this region. Such studies of the onset of collectivity become especially important in light of recent...
The simplest model for non-congruent fluid-fluid phase transition in Coulomb system
Stroev, Nikita
2015-01-01
The simplest model for non-congruent phase transition of gas-liquid type was developed in frames of modified model with no associations of a binary ionic mixture (BIM) on a homogeneous compressible ideal background (or non-ideal) electron gas /BIM($\\sim$)/. The analytical approximation for equation of state equation of state of Potekhin and Chabrier of fully ionized electron-ionic plasma was used for description of the ion-ion correlations (Coulomb non-ideality) in combination with ``linear mixture'' (LM) approximation. Phase equilibrium for the charged species was calculated according to the Gibbs-Guggenheim conditions. The presently considered BIM($\\sim$) model allows to calculate full set of parameters for phase boundaries of non-congruent variant of phase equilibrium and to study all features for this non-congruent phase transition realization in Coulomb system in comparison with the simpler (standard) forced-congruent evaporation mode. In particular, in BIM($\\sim$) there were reproduced two-dimensional r...
Structure of light neutron-rich nuclei through Coulomb dissociation
Indian Academy of Sciences (India)
pp. 535–544. Structure of light neutron-rich nuclei through Coulomb dissociation. U DATTA PRAMANIK, T AUMANN, D CORTINA, H EMLING, H GEISSEL, M HELL-. STR ¨OM, R HOLZMANN, N IWASA, Y LEIFELS, G M ¨UNZENBERG, M REJMUND,. C SCHEIDENBERGER, K S ¨UMMERER, A LEISTENSCHNEIDER. ½.
Spontaneous breakdown of PT symmetry in the complex Coulomb ...
Indian Academy of Sciences (India)
To rectify this problem, a U-shaped trajectory was proposed in ref. [11], in the complex plane, which was parametrized in terms of a real variable. With this, not only was it possible to restore the correct sign of the energy spectrum, but also scattering solutions of the PT -symmetric Coulomb problem could be described,.
Snippets of Physics-Perturbing Coulomb to Avoid Accidents!
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 6. Snippets of Physics - Perturbing Coulomb to Avoid Accidents! T Padmanabhan. Series Article Volume 14 Issue 6 June 2009 pp 622-629. Fulltext. Click here to view fulltext PDF. Permanent link:
Coulomb blockade and superuniversality of the theta angle
Burmistrov, I.S.; Pruisken, A.M.M.
2008-01-01
Based on the Ambegaokar-Eckern-Schön approach to the Coulomb blockade, we develop a complete quantum theory of the single electron transistor. We identify a previously unrecognized physical observable in the problem that, unlike the usual average charge on the island, is robustly quantized for any
A mean field approach to Coulomb blockade for a disordered ...
Indian Academy of Sciences (India)
The Coulomb blockade (CB) in quantum dots (QDs) is by now well documented. It has been used to guide the fabrication of single electron transistors. Even the most sophisticated techniques for synthesizing QDs (e.g. MOCVD/MBE) result in an assembly in which a certain amount of disorder is inevitable. On the other hand, ...
Relativistic Coulomb Green's function in $d$-dimensions
Lee, R. N.; Milstein, A. I.; Terekhov, I. S.
2011-01-01
Using the operator method, the Green's functions of the Dirac and Klein-Gordon equations in the Coulomb potential $-Z\\alpha/r$ are derived for the arbitrary space dimensionality $d$. Nonrelativistic and quasiclassical asymptotics of these Green's functions are considered in detail.
Chaos in a coulombic muffin-tin potential
Energy Technology Data Exchange (ETDEWEB)
Brandis, S. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik
1994-04-01
We study the two-dimensional classical scattering dynamics by a Muffin-Tin potential with 3 Coulomb singularities. A complete symbolic dynamics for the periodic orbits is derivd. The classical trajectories are shown to be hyperbolic everywhere in phase space and to carry no conjugate points. (orig.)
Electrostatic potential of phase boundary in Coulomb systems
Iosilevski, [No Value; Chigvintsev, A
Any interface boundary in an equilibrium system of Coulomb particles is accompanied by the existence of a finite difference in the average electrostatic potential through this boundary. This interface potential drop is a thermodynamic quantity. It depends on temperature only and does not depend on
Plasmon-mediated Coulomb drag between graphene waveguides
DEFF Research Database (Denmark)
Shylau, Artsem A.; Jauho, Antti-Pekka
2014-01-01
We analyze theoretically charge transport in Coulomb coupled graphene waveguides (GWGs). The GWGs are defined using antidot lattices, and the lateral geometry bypasses many technological challenges of earlier designs. The drag resistivity ρD, which is a measure of the many-particle interactions...
Coulomb crystallization in two-component quantum plasmas
Bonitz, M.; Filinov, V. S.; Levashov, P. R.; Fortov, V. E.; Fehske, H.
2006-10-01
Coulomb crystallization is a common phenomenon in trapped (non-neutral) plasmas. In a neutral plasma, however, it is hampered by recombination of electrons and ions. Known examples are ion Coulomb crystals in white dwarf and neutron stars. Here, we predict the conditions under which a Coulomb crystal of heavy particles (e.g. ions) can form in the presence of a degenerate delocalized background of light charges (e.g. electrons): the key requirement is the mass ratio has to exceed a critical value of about 80 [1]. This leads to the prediction of novel types of crystals e.g. in hydrogen and helium. Further, we predict that holes in semiconductors can spontaneously order into a regular lattice in materials with sufficiently flat valence bands. A unified phase diagram of Coulomb crystals in two-component systems is derived and verified by first-principe path-integral Monte Carlo simulations [1-3]. [1] M. Bonitz, V.S. Filinov, V.E. Fortov, P. Levashov, H. Fehske, Phys. Rev. Lett. 95, 235006 (2005), Phys. Rev. Focus, Dec 2005 [2] M. Bonitz, V.S. Filinov, V.E. Fortov, P. Levashov, H. Fehske, J. Phys. A: Math. Gen. 39, 4717 (2006) [3] M. Bonitz, V.S. Filinov, V.E. Fortov, P. Levashov, H. Fehske, Phys. Rev. E (2006)
Multicomponent ionic diffusion in porewaters: Coulombic effects revisited
Boudreau, B.P.; Meysman, F.J.R.; Middelburg, J.J.
2004-01-01
The diffusion of an ion in porewaters cannot occur independently of the other ions in solution as a result of Coulombic coupling, as well as from other effects not considered here. Unfortunately, a longstanding disagreement exists about the correct form and meaning of the equations that describe
Andreoiu, C; Paul, E S; Czosnyka, T; Hammond, N
2002-01-01
We propose to study the Coulomb excitation of a radioactive beam of $^{70}$Se at 2.2 MeV/u obtained from the REX-ISOLDE facility in order to determine the sign of the quadrupole moment and, hence, the sign of the quadrupole deformation. Calculations suggest a 33~\\% sensitivity in Coulomb excitation yield for a nickel target depending on whether the nuclear shape is oblate or prolate. Such a determination would provide compelling evidence for the presence of oblate shapes in the vicinity of N=Z=34.
Phonons in a magnetized Coulomb crystal of ions with polarizable electron background
Baiko, D. A.; Kozhberov, A. A.
2017-11-01
We have studied phonon modes of a body-centered cubic (bcc) Coulomb crystal of ions in the presence of a uniform magnetic field B taking into account the polarizability of the electron background (electron screening) described by the Thomas-Fermi formalism. For k ≫κTF (k and κTF are the phonon wavevector and Thomas-Fermi wavenumber, respectively), electron polarizability is not important. At k ≪κTF , the electron response results in a pronounced effect. One of the three available modes is acoustic. For orthogonal propagation ( k ⊥B ), its frequency Ω is independent of B and κTF . For k ∥B , Ω∝1 /κTF and is independent of B. Another mode is quadratic. Its frequency is ∝1 /(B κTF) for orthogonal propagation and ∝1 /B and independent of κTF for the parallel case. The third mode is optic with Ω≈ωB ( ωB is the ion cyclotron frequency). A general expression is derived for the dynamic matrix of a Coulomb crystal with a polarizable background and more than one ion in the primitive cell. It is employed for a study of a magnetized hexagonal close-packed Coulomb crystal. We have also presented an analysis of phonon polarization vectors in a magnetized bcc crystal with or without screening. The results obtained can be used for realistic calculations of electron-phonon scattering rates and electron thermal and electrical conductivities in neutron star crusts.
Directory of Open Access Journals (Sweden)
Rudziński Wojciech
2013-01-01
Full Text Available Spin-dependent tunneling through a quantum dot coupled to one ferromagnetic and one superconducting electrodes is studied in the Andreev reﬂection (AR regime. Electrical conductance is calculated within the nonequilibrium Green function technique. Eﬀects due to a competition between the Coulomb correlations on the dot and intradot spin-ﬂip processes are considered in the linear transport regime and for diﬀerent coupling strengths between the dot and the external electrodes. It is shown that when a coherent spin rotation is present on the dot, Coulomb interactions may lead to a signiﬁcant enhancement of the AR tunneling current and even to the perfect AR transmission. Origin of occurrence of a variety of the multipeak structure of the linear conductance is also discussed.
Evidence of Coulomb blockade behavior in a quasi-zero-dimensional quantum well on TiO2 surface.
Meunier, Vincent; Pan, M H; Moreau, F; Park, K T; Plummer, E W
2010-08-24
Line defects on the surface of rutile TiO(2)(110) form in pairs separated by 1.2 nm creating a quantum well. The well is effectively closed by the presence of two charged structures at both ends separated by a distance in the 10-20 nm range. As expected for quantum confinement a long period oscillatory feature of the local density of states is observed and attributed to the formation of discrete quantum states inside the system. It is at first glance surprising that the lowest energy quantum state of the well can be observed at room temperature. The properties of the quantum state cannot be explained in an independent-electron, band-like theory. Instead, electron-electron correlation must be included to give a satisfactory picture of the spatial distribution of the charge density. Theory predicts charging energies of 1.30 eV and 1.14 eV for quantum well lengths of 14 nm and 16 nm, respectively, in good agreement with a classical calculation and the size dependence of the capacitance. This observation opens up the possibility of experimentally imaging the transition from a Coulomb blockade localized in a zero-dimensional system to an independent-particle or band-like behavior in an extended one-dimensional system.
Evidence of Coulomb blockade behavior in a quasizero-dimensional quantum well on TiO2 surface
Energy Technology Data Exchange (ETDEWEB)
Meunier, Vincent [ORNL; Pan, Minghu [ORNL; Moreau, Frederick [ORNL; Park, Ken T. [University of Tennessee, Knoxville (UTK) & Baylor University, Waco; Plummer, E. Ward [Louisiana State University
2010-08-01
Line defects on the surface of rutile TiO{sub 2}(110) form in pairs separated by 1.2 nm creating a quantum well. The well is effectively closed by the presence of two charged structures at both ends separated by a distance in the 10-20 nm range. As expected for quantum confinement a long period oscillatory feature of the local density of states is observed and attributed to the formation of discrete quantum states inside the system. It is at first glance surprising that the lowest energy quantum state of the well can be observed at room temperature. The properties of the quantum state cannot be explained in an independent-electron, band-like theory. Instead, electron-electron correlation must be included to give a satisfactory picture of the spatial distribution of the charge density. Theory predicts charging energies of 1.30 eV and 1.14 eV for quantum well lengths of 14 nm and 16 nm, respectively, in good agreement with a classical calculation and the size dependence of the capacitance. This observation opens up the possibility of experimentally imaging the transition from a Coulomb blockade localized in a zero-dimensional system to an independent-particle or band-like behavior in an extended one-dimensional system.
Meana-Pañeda, Rubén; Truhlar, Donald G; Fernández-Ramos, Antonio
2011-03-07
We report a detailed theoretical study of the hydrogen abstraction reaction from methanol by atomic hydrogen. The study includes the analysis of thermal rate constants, branching ratios, and kinetic isotope effects. Specifically, we have performed high-level computations at the MC3BB level together with direct dynamics calculations by canonical variational transition state theory (CVT) with the microcanonically optimized multidimensional tunneling (μOMT) transmission coefficient (CVT/μOMT) to study both the CH(3)OH+H→CH(2)OH+H(2) (R1) reaction and the CH(3)OH+H→CH(3)O+H(2) (R2) reaction. The CVT/μOMT calculations show that reaction R1 dominates in the whole range 298≤T (K)≤2500 and that anharmonic effects on the torsional mode about the C-O bond are important, mainly at high temperatures. The activation energy for the total reaction sum of R1 and R2 reactions changes substantially with temperature and, therefore, the use of straight-line Arrhenius plots is not valid. We recommend the use of new expressions for the total R1 + R2 reaction and for the R1 and R2 individual reactions. © 2011 American Institute of Physics.
Coulomb and Nuclear Breakup at Low Energies: Scaling Laws
Directory of Open Access Journals (Sweden)
Hussein M. S.
2013-12-01
Full Text Available We report on a recent work on the low-energy behavior of the breakup cross section in so far as it has important role in the fusion of weakly bound and halo nuclei at near-barrier energies. We assess the way the nuclear component of this cross section scales with the target mass. In complete accord with previous finding at higher energies we verify that the low energy behavior of the breakup cross section for a given projectile and relative center of mass energy with respect to the Coulomb barrier height scales as the cubic root of the mass number of the target. Surprisingly we find that the Coulomb component of the breakup cross section at these low energies also obeys scaling, but with a linear dependence on the target charge. Our findings are important when planning for experiments involving these exotic nuclei.
Back to epicycles - relativistic Coulomb systems in velocity space
Ben-Ya'acov, Uri
2017-05-01
The study of relativistic Coulomb systems in velocity space is prompted by the fact that the study of Newtonian Kepler/Coulomb systems in velocity space, although less familiar than the analytic solutions in ordinary space, provides a much simpler (also more elegant) method. The simplicity and elegance of the velocity-space method derives from the linearity of the velocity equation, which is the unique feature of 1/r interactions for Newtonian and relativistic systems alike. The various types of possible trajectories are presented, their properties deduced from the orbits in velocity space, accompanied with illustrations. In particular, it is found that the orbits traversed in the relativistic velocity space (which is hyperbolic (H 3) rather than Euclidean) are epicyclic - circles whose centres also rotate - thus the title. Dedicated to the memory of J. D. Bekenstein - physicist, teacher and human
Conductance of a proximitized nanowire in the Coulomb blockade regime
van Heck, B.; Lutchyn, R. M.; Glazman, L. I.
2016-06-01
We identify the leading processes of electron transport across finite-length segments of proximitized nanowires and build a quantitative theory of their two-terminal conductance. In the presence of spin-orbit interaction, a nanowire can be tuned across the topological transition point by an applied magnetic field. Due to a finite segment length, electron transport is controlled by the Coulomb blockade. Upon increasing of the field, the shape and magnitude of the Coulomb blockade peaks in the linear conductance are defined, respectively, by Andreev reflection, single-electron tunneling, and resonant tunneling through the Majorana modes emerging after the topological transition. Our theory provides the framework for the analysis of experiments with proximitized nanowires [such as reported in S. M. Albrecht et al., Nature (London) 531, 206 (2016), 10.1038/nature17162] and identifies the signatures of the topological transition in the two-terminal conductance.
Coulomb repulsion in (TMTSF)2X and (TMTTF)2X
DEFF Research Database (Denmark)
Mortensen, Kell; Engler, E. M.
1985-01-01
On the basis of studies of transport properties of (TMTSF)2 X, (TMTTF)2X and their binary alloys the authors discuss the role of on-site Coulomb repulsion relative to the transfer integrals. In TMTTF-salts U/ta are believed to be large, resulting in a Hubbard gap, whereas U/ta in TMTSF-salts are ......On the basis of studies of transport properties of (TMTSF)2 X, (TMTTF)2X and their binary alloys the authors discuss the role of on-site Coulomb repulsion relative to the transfer integrals. In TMTTF-salts U/ta are believed to be large, resulting in a Hubbard gap, whereas U/ta in TMTSF...
An infinite family of superintegrable deformations of the Coulomb potential
Energy Technology Data Exchange (ETDEWEB)
Post, Sarah [Centre de recherches mathematiques, CP 6128 succ. Centre-Ville, Montreal, QC H3C 3J7 (Canada); Winternitz, Pavel, E-mail: post@CRM.UMontreal.C, E-mail: wintern@CRM.UMontreal.C [Centre de recherches mathematiques and Departement de mathematiques et de statistique, CP 6128 succ. Centre-Ville, Montreal, QC H3C 3J7 (Canada)
2010-06-04
We introduce a new family of Hamiltonians with a deformed Kepler-Coulomb potential dependent on an indexing parameter k. We show that this family is superintegrable for all rational k and compute the classical trajectories and quantum wavefunctions. We show that this system is related, via coupling constant metamorphosis, to a family of superintegrable deformations of the harmonic oscillator given by Tremblay, Turbiner and Winternitz. In doing so, we prove that all Hamiltonians with an oscillator term are related by coupling constant metamorphosis to systems with a Kepler-Coulomb term, both on Euclidean space. We also look at the effect of the transformation on the integrals of the motion, the classical trajectories and the wavefunctions, and give the transformed integrals explicitly for the classical system. (fast track communication)
An entropic form for NLFP with coulombic-like potential
Energy Technology Data Exchange (ETDEWEB)
Grassi, A., E-mail: agrassi@unict.it [Dipartimento di Scienze del Farmaco, Università di Catania, V.le A. Doria 6, 95125 Catania (Italy)
2012-01-30
Here it is proposed a new entropy form for which it is possible to obtain a stationary solution of the Non-Linear Fokker–Planck equation (NLFP) with coulombic-like potentials. The general properties of this new entropy form are shown and the results are compared with those obtained by other entropy forms. Finally, the behavior of the stationary solution in presence of two point charges is also shown. -- Highlights: ► In this Letter we have proposed a new form of entropy. ► Starting from this new entropy form a Non-Linear Fokker–Planck equation has been derived. ► The stationary solution of the Non-Linear Fokker–Planck equation is obtained by using an external coulombic-like potential. ► A comparison with other forms of entropies has been proposed in the case of a single or two point charges.
Structural phase transitions and topological defects in ion Coulomb crystals
Energy Technology Data Exchange (ETDEWEB)
Partner, Heather L. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Nigmatullin, Ramil [Institute of Quantum Physics, Ulm Univ., Ulm (Germany); Burgermeister, Tobias [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Keller, Jonas [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Pyka, Karsten [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Plenio, Martin B. [Center for Integrated Quantum Science and Technology, Ulm Univ., Ulm, (Germany):Institute for Theoretical Physics, Ulm Univ.,Ulm, (Germany); Retzker, Alex [Racah Institute of Physics, The Hebrew University of Jerusalem, Givat Ram (Israel); Zurek, Wojciech Hubert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); del Campo, Adolfo [Univ. of Massachusetts, Amherst, MA (United States). Dept. of Physics; Mehlstaubler, Tanja E. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)
2014-11-19
We use laser-cooled ion Coulomb crystals in the well-controlled environment of a harmonic radiofrequency ion trap to investigate phase transitions and defect formation. Topological defects in ion Coulomb crystals (kinks) have been recently proposed for studies of nonlinear physics with solitons and as carriers of quantum information. Defects form when a symmetry breaking phase transition is crossed non-adiabatically. For a second order phase transition, the Kibble-Zurek mechanism predicts that the formation of these defects follows a power law scaling in the rate of the transition. We demonstrate a scaling of defect density and describe kink dynamics and stability. We further discuss the implementation of mass defects and electric fields as first steps toward controlled kink preparation and manipulation.
Fumino, Koichi; Reimann, Sebastian; Ludwig, Ralf
2014-10-28
Ionic liquids are defined as salts composed solely of ions with melting points below 100 °C. These remarkable liquids have unique and fascinating properties and offer new opportunities for science and technology. New combinations of ions provide changing physical properties and thus novel potential applications for this class of liquid materials. To a large extent, the structure and properties of ionic liquids are determined by the intermolecular interaction between anions and cations. In this perspective we show that far infrared and terahertz spectroscopy are suitable methods for studying the cation-anion interaction in these Coulomb fluids. The interpretation of the measured low frequency spectra is supported by density functional theory calculations and molecular dynamics simulations. We present results for selected aprotic and protic ionic liquids and their mixtures with molecular solvents. In particular, we focus on the strength and type of intermolecular interaction and how both parameters are influenced by the character of the ions and their combinations. We show that the total interaction between cations and anions is a result of a subtle balance between Coulomb forces, hydrogen bonds and dispersion forces. For protic ionic liquids we could measure distinct vibrational modes in the low frequency spectra indicating clearly the cation-anion interaction characterized by linear and medium to strong hydrogen bonds. Using isotopic substitution we have been able to dissect frequency shifts related to pure interaction strength between cations and anions and to different reduced masses only. In this context we also show how these different types of interaction may influence the physical properties of ionic liquids such as the melting point, viscosity or enthalpy of vaporization. Furthermore we demonstrate that low frequency spectroscopy can also be used for studying ion speciation. Low vibrational features can be assigned to contact ion pairs and solvent separated
Band Gap, Excitons, and Coulomb Interaction in Solid C60
Lof, R.W.; Veenendaal, M.A. van; Jonkman, H.T.; Sawatzky, G.A.; Koopmans, H.
1992-01-01
The band gap of solid C60 is found to be 2.3 ± 0.1 eV. The on-site molecular C60 Coulomb interaction (U) as determined from the KVV C60 Auger spectrum is found to be 1.6 ± 0.2 eV. This value of U is shown to lead to Frenkel-type molecular excitons in the 1.5-2 eV range. These results lead us to
Stability characterizations of fixtured rigid bodies with Coulomb friction
Energy Technology Data Exchange (ETDEWEB)
PANG,J.S.; TRINKLE,JEFFREY C.
2000-02-15
This paper formally introduces several stability characterizations of fixtured three-dimensional rigid bodies initially at rest and in unilateral contact with Coulomb friction. These characterizations, weak stability and strong stability, arise naturally from the dynamic model of the system, formulated as a complementarity problem. Using the tools of complementarity theory, these characterizations are studied in detail to understand their properties and to develop techniques to identify the stability classifications of general systems subjected to known external loads.
Coulomb excitation of radioactive {sup 20,21}Na
Energy Technology Data Exchange (ETDEWEB)
Schumaker, M.A.; Svensson, C.E.; Bandyopadhyay, D.; Demand, G.A.; Finlay, P.; Green, K.L.; Grinyer, G.F.; Leach, K.G.; Phillips, A.A.; Wong, J. [Univ. of Guelph, Dept. of Physics, Guelph, Ontario (Canada); Cline, D.; Hayes, A.B.; Whitbeck, A. [Univ. of Rochester, Dept. of Physics and Astronomy, Rochester, NY (United States); Hackman, G.; Pearson, C.; Andreyev, A.; Ball, G.C.; Buchmann, L.; Churchman, R.; Cifarelli, F.; Lee, G.; Maharaj, R.; Morton, A.C.; Padilla-Rodal, E.; Ruiz, C.; Williams, S.J. [TRIUMF, Vancouver, British Columbia (Canada); Wu, C.Y.; Becker, J.A. [Lawrence Livermore National Lab., Livermore, CA (United States); Austin, R.A.E.; Gallant, A.T. [Saint Mary' s Univ., Dept. of Astronomy and Physics, Halifax, Nova Scotia (Canada); Boston, A.J.; Boston, H.C.; Cooper, R.J.; Dimmock, M.R.; Grint, A.N.; Harkness, L.J.; Nelson, L.; Nolan, P.J.; Scraggs, D.P. [Univ. of Liverpool, Dept. of Physics, Liverpool (United Kingdom); Cross, D.S.; Ressler, J.J.; Wan, J.M. [Simon Fraser Univ., Dept. of Chemistry, Burnaby, British Columbia (Canada); Dashdorj, D. [North Carolina State Univ., Dept. of Physics, Raleigh, NC (United States); Drake, T.E. [Univ. of Toronto, Dept. of Physics, Toronto, Ontario (Canada); Garrett, P.E. [Univ. of Guelph, Dept. of Physics, Guelph, Ontario (Canada); TRIUMF, Vancouver, British Columbia (Canada); Kanungo, R. [TRIUMF, Vancouver, British Columbia (Canada); Saint Mary' s Univ., Dept. of Astronomy and Physics, Halifax, Nova Scotia (Canada); Lisetskiy, A.F. [Univ. of Arizona, Dept. of Physics, Tucson, AZ (United States); Martin, J.P. [Universite de Montreal, Montreal, Quebec (Canada); Moisan, F.; Roy, R. [Universite de Laval, Laval, Quebec (Canada); Mythili, S. [TRIUMF, Vancouver, British Columbia (Canada); Univ. of British Columbia, Dept. of Physics and Astronomy, British Columbia (Canada); Newman, O. [TRIUMF, Vancouver, British Columbia (Canada); Univ. of Surrey, Guildford (United Kingdom)] [and others
2009-12-15
The low-energy structures of the radioactive nuclei {sup 20,21}Na have been examined using Coulomb excitation at the TRIUMF-ISAC radioactive ion beam facility. Beams of {proportional_to}5 x 10{sup 6} ions/s were accelerated to 1.7 MeV/A and Coulomb excited in a 0.5 mg/cm {sup 2} {sup nat}Ti target. Two TIGRESS HPGe clover detectors perpendicular to the beam axis were used for {gamma} -ray detection, while scattered nuclei were observed by the Si detector BAMBINO. For {sup 21}Na, Coulomb excitation from the 3/2{sup +} ground state to the first excited 5/2{sup +} state was observed, while for {sup 20}Na, Coulomb excitation was observed from the 2{sup +} ground state to the first excited 3{sup +} and 4{sup +} states. For both beams, B ({lambda} L) values were determined using the 2{sup +} {yields} 0{sup +} de-excitation in {sup 48}Ti as a reference. The resulting B(E2) arrow up and down value for {sup 21}Na is 137{+-}9 e{sup 2}fm{sup 4}, while the resulting B({lambda} L) arrow up and down values for {sup 20}Na are 55{+-}6 e{sup 2}fm{sup 4} for the 3{sup +} {yields} 2{sup +}, 35.7{+-}5.7 e{sup 2} fm{sup 4} for the 4{sup +} {yields} 2{sup +}, and 0.154{+-}0.030 {mu}{sub N}{sup 2} for the 4{sup +}{yields}3{sup +} transitions. This analysis significantly improves the measurement of the {sup 21}Na B(E2) value, and provides the first experimental determination of B({lambda} L) values for the proton dripline nucleus {sup 20}Na. (orig.)
National Oceanic and Atmospheric Administration, Department of Commerce — The Magnetic Field Calculator will calculate the total magnetic field, including components (declination, inclination, horizontal intensity, northerly intensity,...
Optimal reconfigurations of two-craft Coulomb formations along manifolds
Jones, Drew R.; Schaub, Hanspeter
2013-02-01
Coulomb formations refer to swarms of closely flying spacecraft, in which the net electric charge of each vehicle is controlled. Active charge control is central to this concept and enables a propulsion system with highly desirable characteristics, albeit with limited controllability. Numerous Coulomb formation equilibria have been derived, but to maintain and maneuver these configurations, some inertial thrust is required to supplement the nearly propellant-less charge control. In this work, invariant manifold theory is applied to two-craft Coulomb equilibria, which are admitted in a linearized two-body gravity model. The manifolds associated with these systems are analyzed for the first time, and are then utilized as part of a general procedure for formulating optimal reconfigurations. Specifically, uncontrolled flows along the manifolds are sought which provide near continuous transfers from one equilibrium to another. Control is then introduced to match continuity, while minimizing inertial thrusting. This methodology aims to exploit uncontrolled motions and charge control to realize the shape-changing ability of these formations, without large inertial control efforts. Some variations in formulating and parameterizing the optimal transfers are discussed, and analytical expressions are derived to aid in establishing control parameter limits, under certain assumptions. Numerical results are provided, as demonstrative examples of the optimization procedure, using relatively simple control approximations. Finally, Particle Swarm Optimization, a novel stochastic method, is used with considerable success to solve the numerically difficult parameter optimization problems.
Regularized friction and continuation: Comparison with Coulomb's law
Vigué, Pierre; Vergez, Christophe; Karkar, Sami; Cochelin, Bruno
2017-02-01
Periodic solutions of systems with friction are difficult to investigate because of the non-smooth nature of friction laws. This paper examines periodic solutions and most notably stick-slip, on a simple one-degree-of-freedom system (mass, spring, damper, and belt), with Coulomb's friction law, and with a regularized friction law (i.e. the friction coefficient becomes a function of relative speed, with a stiffness parameter). With Coulomb's law, the stick-slip solution is constructed step by step, which gives a usable existence condition. With the regularized law, the Asymptotic Numerical Method and the Harmonic Balance Method provide bifurcation diagrams with respect to the belt speed or normal force, and for several values of the regularization parameter. Formulations from the Coulomb case give the means of a comparison between regularized solutions and a standard reference. With an appropriate definition, regularized stick-slip motion exists, its amplitude increases with respect to the belt speed and its pulsation decreases with respect to the normal force.
Coulomb blockade phenomena observed in supported metallic nanoislands
Directory of Open Access Journals (Sweden)
Wolf-Dieter eSchneider
2013-09-01
Full Text Available The electron transport properties of single crystalline metallic nanostructures in the Coulomb blockade regime have been investigated by low-temperature scanning tunneling spectroscopy. To this end, nanoscale flat-top Pb islands with well-defined geometries are grown on NaCl-covered Ag(111 substrate. The tunneling spectra acquired at 4.6 K on the Pb nanoislands reflect the presence of single electron tunneling processes across the double-barrier tunnel junction (DBTJ. By a controlled change of the tip-island tunnel distance, the spectra display the characteristic evolution from Coulomb blockade (CB to Coulomb staircase (CS regime. Simulations within the semi-classical orthodox theory allow us to extract quantitatively the parameters characterizing the DBTJ, i. e., the resistances, capacitances, and the residual charge Q0. Manipulation of Q0 is achieved by controlled application of voltage pulses on the Pb islands. Moreover, under specific tunneling conditions, the influence of the tip-island junction on Q0 is revealed in topographic images of the Pb islands.
Jackson, M I; Hiley, M J; Yeadon, M R
2011-10-13
In the table contact phase of gymnastics vaulting both dynamic and static friction act. The purpose of this study was to develop a method of simulating Coulomb friction that incorporated both dynamic and static phases and to compare the results with those obtained using a pseudo-Coulomb implementation of friction when applied to the table contact phase of gymnastics vaulting. Kinematic data were obtained from an elite level gymnast performing handspring straight somersault vaults using a Vicon optoelectronic motion capture system. An angle-driven computer model of vaulting that simulated the interaction between a seven segment gymnast and a single segment vaulting table during the table contact phase of the vault was developed. Both dynamic and static friction were incorporated within the model by switching between two implementations of the tangential frictional force. Two vaulting trials were used to determine the model parameters using a genetic algorithm to match simulations to recorded performances. A third independent trial was used to evaluate the model and close agreement was found between the simulation and the recorded performance with an overall difference of 13.5%. The two-state simulation model was found to be capable of replicating performance at take-off and also of replicating key contact phase features such as the normal and tangential motion of the hands. The results of the two-state model were compared to those using a pseudo-Coulomb friction implementation within the simulation model. The two-state model achieved similar overall results to those of the pseudo-Coulomb model but obtained solutions more rapidly. Copyright © 2011 Elsevier Ltd. All rights reserved.
Scattering in a Coulomb potential: a velocity space point of view
Energy Technology Data Exchange (ETDEWEB)
Gonzalez V, A.; Guillaumin E, E. [Laboratorio de Sistemas Dinamicos. Departamento de Ciencias Basicas, Universidad Autonoma Metropolitana-Azcapotzalco. (Mexico); Nunez Y, H.N. [Instituto de Fisica Luis Rivera Terrazas, Benemerita Universidad Autonoma de Puebla. Puebla (Mexico); Salas B, A.L. [Departamento de Fisica, Facultad de Ciencias. Universidad Nacional Autonoma de Mexico, Mexico D.F. (Mexico)
1998-10-01
The unbounded motion of a particle in a Coulomb field is analyzed from the point of view of velocity space using both the hodograph and the properties of the Hamilton vector. Many features of the motion even the classical deflection function and the differential scattering cross section in velocity space follow from simple geometrical considerations, the standard Rutherford scattering formula in configuration space can then be simply obtained from them. We address the connection between initial conditions and the properties of the scattering orbits with the help of the Hamilton vector. We also discuss an approximate method for calculating the effect of a central perturbation on the properties of the hodograph and on the Rutherford differential scattering cross section. (Author)
Structure Effects in Collisions Induced by Halo and Weakly Bound Nuclei Around the Coulomb Barrier
Scuderi, V; Torresi, D; Fisichella, M; Borge, M J G; Randisi, G; Milin, M; Figuera, P; Raabe, R; Di Pietro, A; Amorini, F; Fraile, L M; Vidal, A M; Rizzo, F; Zadro, M; Gomez-Camacho, J; Pellegriti, M G; Papa, M; Jeppesen, H; Santonocito, D; Sanchez, E M R; Acosta, L; Tengblad, O; Lattuada, M; Musumarra, A; Scalia, G
2010-01-01
In this contribution, results concerning different reaction channels for the collisions induced by the three Be isotopes, Be-9,Be-10,Be-11, on a Zn-64 target at energies around the Coulomb barrier will be presented. The experiments with the radioactive Be-10,Be-11 beams were performed at REX-ISOLDE (CERN) whereas the experiment with the stable weakly bound Be-9 beam was performed at LNS Catania. Elastic scattering angular distributions have been measured for the three systems Be-9,Be-10,Be-11 + Zn-64 at the same center of mass energy. The angular distributions were analyzed with optical potentials and reaction cross sections were obtained from optical model calculations, performed with the code PTOLEMY. For the Be-11 + Zn-64 reaction, the break-up angular distribution was also measured.
Detassis, Fabrizio; Fritz, Lars; Grubinskas, Simonas
2017-11-01
Recently, the existence of Dirac/Weyl cones in three-dimensional systems has been demonstrated experimentally. While in high-energy physics the isotropy of the Dirac/Weyl cones is guaranteed by relativistic invariance, in condensed-matter systems corrections to this can occur, with one possible type being a tilt. In this paper, we study the effect of tilted Weyl cones in collective effects. We study both the optical conductivity as well as the polarization function. We also investigate the perturbative effect of long-range Coulomb interactions using a renormalization-group calculation. We find that the tilt is perturbatively renormalized towards zero and at low energies the system flows to an effectively untilted theory.
Thermoelectrics in Coulomb-coupled quantum dots: Cotunneling and energy-dependent lead couplings
DEFF Research Database (Denmark)
Walldorf, Nicklas; Jauho, Antti-Pekka; Kaasbjerg, Kristen
2017-01-01
-dependent lead couplings on the heat currents in a system of two CCQDs. We find that cotunneling processes (i) can dominate the off-resonant heat currents at low temperature and bias compared to the interdot interaction, and (ii) give rise to a pronounced reduction of the cooling power achievable...... with the recently demonstrated Maxwell’s demon coolingmechanism. Furthermore, we demonstrate that the cooling power can be boosted significantly by carefully engineering the energy dependence of the lead couplings to filter out undesired transport processes. Our findings emphasize the importance of higher......We study thermoelectric effects in Coulomb-coupled quantum-dot (CCQD) systems beyond lowest-order tunneling processes and the often applied wide-band approximation. To this end, we present a master-equation (ME) approach based on a perturbative T -matrix calculation of the charge and heat tunneling...
Microscopic study of {sup 6}He elastic scattering around the Coulomb barrier
Energy Technology Data Exchange (ETDEWEB)
Descouvemont, P. [Physique Nucléaire Théorique et Physique Mathématique, C.P. 229, Université Libre de Bruxelles (ULB), B 1050 Brussels (Belgium)
2016-07-07
We investigate {sup 6}He scattering on {sup 27}Al, {sup 58}Ni, {sup 120}Sn, and {sup 208}Pb in a microscopic version of the Continuum Discretized Coupled Channel (CDCC) method. We essentially focus on energies around the Coulomb barrier. The {sup 6}He nucleus is described by an antisymmetric 6-nucleon wave function, defined in the Resonating Group Method. The {sup 6}He continuum is simulated by square-integrable positive-energy states. The model does not depend on any adjustable parameter as it is based only on well known nucleon-target potentials. We show that experimental elastic cross sections are fairly well reproduced. The calculation suggests that breakup effects increase for high target masses. For a light system such as {sup 6}He+{sup 27}Al, breakup effects are small, and a single-channel approximation provides fair results.
Hellweg, Arnim; Rappoport, Dmitrij
2015-01-14
We report optimized auxiliary basis sets for use with the Karlsruhe segmented contracted basis sets including moderately diffuse basis functions (Rappoport and Furche, J. Chem. Phys., 2010, 133, 134105) in resolution-of-the-identity (RI) post-self-consistent field (post-SCF) computations for the elements H-Rn (except lanthanides). The errors of the RI approximation using optimized auxiliary basis sets are analyzed on a comprehensive test set of molecules containing the most common oxidation states of each element and do not exceed those of the corresponding unaugmented basis sets. During these studies an unsatisfying performance of the def2-SVP and def2-QZVPP auxiliary basis sets for Barium was found and improved sets are provided. We establish the versatility of the def2-SVPD, def2-TZVPPD, and def2-QZVPPD basis sets for RI-MP2 and RI-CC (coupled-cluster) energy and property calculations. The influence of diffuse basis functions on correlation energy, basis set superposition error, atomic electron affinity, dipole moments, and computational timings is evaluated at different levels of theory using benchmark sets and showcase examples.
Physics of the Non-Abelian Coulomb Phase
DEFF Research Database (Denmark)
Ryttov, Thomas A.; Shrock, Robert
2018-01-01
We consider a vectorial, asymptotically free SU($N_c$) gauge theory with $N_f$ fermions in a representation $R$ having an infrared (IR) fixed point. We calculate and analyze Pad\\'e approximants to scheme-independent series expansions for physical quantities at this IR fixed point, including...
Stanke, Monica; Bubin, Sergiy; Adamowicz, Ludwik
2009-06-01
Very accurate variational calculations of the fundamental pure vibrational transitions of the H3eH4e+ and L7iH+ ions are performed within the framework that does not assume the Born-Oppenheimer (BO) approximation. The non-BO wave functions expanded in terms of one-center explicitly correlated Gaussian functions multiplied by even powers of the internuclear distance are used to calculate the leading relativistic corrections. Up to 10000 Gaussian functions are used for each state. It is shown that the experimental H3eH4e+ fundamental transitions is reproduced within 0.06cm-1 by the calculations. A similar precision is expected for the calculated, but still unmeasured, fundamental transition of L7iH+ . Thus, three-electron diatomic systems are calculated with a similar accuracy as two-electron systems.
Abram, M.; Zegrodnik, M.; Spałek, J.
2017-09-01
In the first part of the paper, we study the stability of antiferromagnetic (AF), charge density wave (CDW), and superconducting (SC) states within the t-J-U-V model of strongly correlated electrons by using the statistically consistent Gutzwiller approximation (SGA). We concentrate on the role of the intersite Coulomb interaction term V in stabilizing the CDW phase. In particular, we show that the charge ordering appears only above a critical value of V in a limited hole-doping range δ. The effect of the V term on SC and AF phases is that a strong interaction suppresses SC, whereas the AF order is not significantly influenced by its presence. In the second part, separate calculations for the case of a pure SC phase have been carried out within an extended approach (the diagrammatic expansion for the Gutzwiller wave function, DE-GWF) in order to analyze the influence of the intersite Coulomb repulsion on the SC phase with the higher-order corrections included beyond the SGA method. The upper concentration for the SC disappearance decreases with increasing V, bringing the results closer to experiment. In appendices A and B we discuss the ambiguity connected with the choice of the Gutzwiller renormalization factors within the renormalized mean filed theory when either AF or CDW orders are considered. At the end, we overview briefly the possible extensions of the current models to put descriptions of the SC, AF, and CDW states on equal footing.
Mesoscopic Coulomb Blockade in a Quantum Dot with Two Open QPCs
Amasha, Sami; Rau, Ileana; Grobis, Michael; Potok, Ron; Shtrikman, Hadas; Goldhaber-Gordon, David
2009-03-01
A quantum dot consists of a confined droplet of electrons connected to an electron reservoir by two quantum point contacts (QPCs). When the conductance of each of these QPCs is less than 2e^2/h, the dot is in the closed regime and Coulomb Blockade effects dominate the transport properties. Open quantum dots, in which QPC conductances are 2e^2/h or above, are generally thought to be well-described by non-interacting electron theory. While Mesoscopic Coulomb Blockade (MCB) effects can occur in a quantum dot with one open and one closed QPC, these effects are expected to be absent for quantum dots with two open QPCs. We have investigated the transport properties of a 1.5 μm^2 and a 3 μm^2 lateral GaAs/AlGaAs quantum dot in the open regime and find a clear signature of MCB. We will discuss the dependence of MCB on various controllable parameters, including magnetic field, temperature, and bias.
Coulomb Excitation of a Neutron-Rich $^{88}$Kr Beam Search for Mixed Symmetry States
Andreoiu, C; Napiorkowski, P J; Iwanicki, J S
2002-01-01
We propose to use the ISOLDE/REX/MINIBALL/CD set-up to perform a Coulomb Excitation experiment with a $^{88}$Kr radioactive beam. The motivation includes a search for $Mixed$ $Symmetry$ states predicted by the IBM-2 model, gathering more spectroscopy data about the $^{88}$Kr nucleus and extending shape coexistence studies (performed previously by the proposers for neutron-deficient Kr isotopes) to the neutron-rich side. The proposed experiment will provide data complementary to the Coulomb Excitation of a relativistic $^{88}$Kr beam proposed by D. Tonev et al. for a RISING experiment. A total of 12 days of beam time is necessary for the experiment, equally divided into two runs. One run with a 2.2 MeV/A beam energy on a $^{48}$Ti target and a second run with the maximum available REX energy of 3.1 MeV/A on a $^{208}$Pb target are requested. Using either a UC$_{x}$ or ThC$_{x}$ fissioning primary target coupled with a plasma source by a cooled transfer line seems to be the best choice for the proposed experime...
Continuum RPA calculation of escape widths
Energy Technology Data Exchange (ETDEWEB)
Vertse, T. (Inst. of Nuclear Research, Hungarian Academy of Sciences, Debrecen (Hungary)); Curutchet, P.; Liotta, R.J. (Manne Siegbahn Inst. of Physics, Stockholm (Sweden)); Bang, J. (Niels Bohr Inst., Copenhagen (Denmark)); Giai, N. van (Inst. de Physique Nucleaire, 91 - Orsay (France))
1991-07-25
Particle-hole partial decay widths are calculated within the continuum RPA exactly, i.e. without any further approximation, in a square well plus Coulomb potential and using a separable residual interaction. The results are compared with the ones obtained by making pole expansions of the single-particle Green functions (Berggren and Mittag-Leffler). It is found that the Berggren and Mittag-Leffler expansions give results in good agreement with the 'exact' ones. (orig.).
Multiple Coulomb excitation experiment of sup 6 sup 6 Zn
Koizumi, M; Oshima, M; Osa, A; Kimura, A; Hatsukawa, Y; Shizuma, T; Hayakawa, T; Matsuda, M; Katakura, J; Seki, A; Czosnyka, T; Sugawara, M; Morikawa, T; Kusakari, H
2003-01-01
A Coulomb excitation experiment was carried out with a sup 6 sup 6 Zn beam bombarding a sup n sup a sup t Pb target. Four E2 matrix elements and the quadrupole moment of the 2 sub 1 sup + state were derived with the least-squares search code GOSIA. According to the B(E2) values, the ground band can be interpreted as a quasirotational band. It was found that the 2 sub 1 sup + level has a positive quadrupole moment, which may be interpreted as a soft triaxial deformation.
About the Absence of Exotics and the Coulomb Branch Formula
Del Zotto, Michele; Sen, Ashoke
2017-11-01
The absence of exotics is a conjectural property of the spectrum of BPS states of four-dimensional {N=2} supersymmetric QFT's. In this note we revisit the precise statement of this conjecture, and develop a general strategy that, if applicable, entails the absence of exotic BPS states. Our method is based on the Coulomb branch formula and on quiver mutations. In particular, we obtain the absence of exotic BPS states for all pure SYM theories with simple, simply-laced gauge group G, and, as a corollary, of infinitely many other lagrangian {N=2} theories.
Improving Student Understanding of Coulomb's Law and Gauss's Law
Singh, Chandralekha
2016-01-01
We discuss the development and evaluation of five research-based tutorials on Coulomb's law, superposition, symmetry and Gauss's Law to help students in the calculus-based introductory physics courses learn these concepts. We discuss the performance of students on the pre-/post-tests given before and after the tutorials in three calculus-based introductory physics courses. We also discuss the performance of students who used the tutorials and those who did not use it on a multiple-choice test which employs concepts covered in the tutorials.
Multiple Coulomb excitation experiment of {sup 66}Zn
Energy Technology Data Exchange (ETDEWEB)
Koizumi, M.; Toh, Y.; Oshima, M.; Osa, A.; Kimura, A.; Hatsukawa, Y.; Shizuma, T.; Hayakawa, T.; Matsuda, M.; Katakura, J. [Japan Atomic Energy Research Institute, Tokai, 319-1195, Ibaraki (Japan); Seki, A. [Japan Atomic Energy Research Institute, Tokai, 319-1195, Ibaraki (Japan); Graduate School of Science and Engineering, Ibaraki University, Bunkyo 2-1-1, Mito, 310-8512, Ibaraki (Japan); Czosnyka, T. [Heavy Ion Laboratory, Warsaw University, Pasteura 5a, 02-093, Warszawa (Poland); Sugawara, M. [Chiba Institute of Technology, Narashino, 275-0023, Chiba (Japan); Morikawa, T. [Kyushu University, Hakozaki, 812-8581, Fukuoka (Japan); Kusakari, H. [Chiba University, Inage-ku, 263-8522, Chiba (Japan)
2003-09-01
A Coulomb excitation experiment was carried out with a {sup 66}Zn beam bombarding a {sup nat}Pb target. Four E2 matrix elements and the quadrupole moment of the 2{sub 1}{sup +} state were derived with the least-squares search code GOSIA. According to the B(E2) values, the ground band can be interpreted as a quasirotational band. It was found that the 2{sub 1}{sup +} level has a positive quadrupole moment, which may be interpreted as a soft triaxial deformation. (orig.)
Hadronic correction to Coulomb potential between quarks and diquark structure
Energy Technology Data Exchange (ETDEWEB)
Xin-Heng, Guo [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Xue-Qian, Li; Peng-Nian, Shen [Academia Sinica, Beijing, BJ (China). Inst. of High Energy Physics; Chuang, Wang [Nankai Univ., TJ (China). Dept. of Physics
1997-07-01
We have studied the hadronic correction from the background pion fields due to the chiral symmetry breaking to the Coulomb potential that governs the short-distance behavior of the interactions between the bound quarks. The background fields are associated with the constituent quark mass. We find a modified form which favors the diquark structure. We also roughly estimate an influence of this correction on the phase shifts in nucleon scattering and find that it may cause an extra middle range attraction between nucleons which is expected. (author) 17 refs., 4 figs.
Nonlocal and nonlinear electrostatics of a dipolar Coulomb fluid.
Sahin, Buyukdagli; Ralf, Blossey
2014-07-16
We study a model Coulomb fluid consisting of dipolar solvent molecules of finite extent which generalizes the point-like dipolar Poisson-Boltzmann model (DPB) previously introduced by Coalson and Duncan (1996 J. Phys. Chem. 100 2612) and Abrashkin et al (2007 Phys. Rev. Lett. 99 077801). We formulate a nonlocal Poisson-Boltzmann equation (NLPB) and study both linear and nonlinear dielectric response in this model for the case of a single plane geometry. Our results shed light on the relevance of nonlocal versus nonlinear effects in continuum models of material electrostatics.
Phonon-mediated versus coulombic backaction in quantum dot circuits.
Harbusch, D; Taubert, D; Tranitz, H P; Wegscheider, W; Ludwig, S
2010-05-14
Quantum point contacts (QPCs) are commonly employed to detect capacitively the charge state of coupled quantum dots (QDs). An indirect backaction of a biased QPC onto a double QD laterally defined in a GaAs/AlGaAs heterostructure is observed. Energy is emitted by nonequilibrium charge carriers in the leads of the biased QPC. Part of this energy is absorbed by the double QD where it causes charge fluctuations that can be observed under certain conditions in its stability diagram. By investigating the spectrum of the absorbed energy, we find that both acoustic phonons and Coulomb interaction can be involved in the backaction, depending on the geometry and coupling constants.
"Coulombic Viscosity" In Granular Materials: Planetary and Astrophysical Implications
Marshall, J. R.
1999-09-01
The term "Coulombic viscosity" is introduced here to define an empirically observed phenomenon from experiments conducted in both microgravity, and in ground-based 1-g conditions. In the latter case, a sand attrition device was employed to test the longevity of aeolian materials by creating two intersecting grain-circulation paths or cells that would lead to most of the grain energy being expended on grain-to-grain collisions (simulating dune systems). In the areas in the device where gravitationally-driven grain-slurries recycled the sand, the slurries moved with a boundary-layer impeded motion down the chamber walls. Excessive electrostatic charging of the grains during these experiments was prevented by the use of an a.c. corona (created by a Tesla coil) through which the grains passed on every cycle. This created both positive and negative ions which neutralized the triboelectrically-generated grain charges. When the corona was switched on, the velocity of the wall-attached slurries increased by a factor of two as approximately determined by direct observation. What appeared to be a freely-flowing slurry of grains impeded only by intergranular mechanical friction, had obviously been significantly retarded in its motion by electrostatic forces between the grains; with the charging reduced, the grains were able to move past one another without a flow "viscosity" imposed by the Coulombic intergranular forces. A similar phenomenon was observed during microgravity experiments aboard Space Shuttle in USML-1 & USML-2 spacelabs where freely-suspended clouds of sand were being investigated for their potential to for-m aggregates. In this environment, the grains were also charged electrostatically (by natural processes prior to flight), but were free from the intervention of gravity in their interactions. The grains were dispersed into dense clouds by bursts of air turbulence and allowed to form aggregates as the ballistic and turbulent motions damped out. During this
Coulombic quantum liquids in spin-1/2 pyrochlores.
Savary, Lucile; Balents, Leon
2012-01-20
We develop a nonperturbative gauge mean field theory (gMFT) method to study a general effective spin-1/2 model for magnetism in rare earth pyrochlores. gMFT is based on a novel exact slave-particle formulation, and matches both the perturbative regime near the classical spin ice limit and the semiclassical approximation far from it. We show that the full phase diagram contains two exotic phases: a quantum spin liquid and a Coulombic ferromagnet, both of which support deconfined spinon excitations and emergent quantum electrodynamics. Phenomenological properties of these phases are discussed. © 2012 American Physical Society
Probing the decay mechanism of hot nuclei by Coulomb chronometry
Directory of Open Access Journals (Sweden)
Gruyer D.
2015-01-01
Full Text Available In this contribution, we propose a new Coulomb chronometer suitable for three-fragment exit channels. We use this chronometer to extract the evolution of the fragment emission time in 129Xe+catSn central collisions from 12 to 25 MeV/A bombarding energy. The involved time scale becomes compatible with simultaneous threefragment break-up above E* = 4.0 ± 0.5 MeV/A, which can be interpreted as the energy required for the onset of multifragmentation.
Structure effects in the reactions {sup 9,10,11}Be+{sup 64}Zn at the Coulomb barrier
Energy Technology Data Exchange (ETDEWEB)
Scuderi, V; Amorini, F; Fisichella, M; Lattuada, M; Pellegriti, M G; Randisi, G; Rizzo, F [Dipartimento di Fisica ed Astronomia Universita di Catania, Catania (Italy); Pietro, A Di; Figuera, P; Musumarra, A; Papa, M [INFN-Laboratori Nazionali del Sud and Sezione di Catania (Italy); Acosta, L; Martel, I; Perez-Bernal, F [Departamento de Fisica Aplicada Universidad de Huelva, Huelva (Spain); Borge, M J G [Instituto de Estructura de la Materia CSIC, Madrid (Spain); Fraile, L M; Jeppesen, H [CERN, Geneva (Switzerland); Gomez-Camacho, J [Departamento de Fisica Atomica Molecular Nuclear Universidad de Sevilla, Sevilla (Spain); Milin, M [Department of Physics Faculty of Science University of Zagreb, Zagreb (Croatia); Raabe, R, E-mail: scuderiv@lns.infn.it [Instituut voor Kern-en Stralingsfysica University of Leuven, Leuven (Belgium)
2011-01-01
Elastic scattering and direct reactions have been studied for the collisions induced by the three Beryllium isotopes {sup 9,10,11}Be, on a medium mass {sup 64}Zn target at energies around the Coulomb barrier. The elastic scattering angular distributions, measured for the three systems at the same center of mass energy, were analyzed within the Optical Model and reaction cross-sections were deduced from optical model calculations. For the {sup 11}Be induced reaction the transfer/break-up angular distribution was also extracted.
Harb, Moussab
2014-09-11
Relevant properties to visible-light overall water splitting reactions of perfect and self-defective bulk Ta3N5 semiconductor photocatalysts are investigated using accurate first-principles quantum calculations on the basis of density functional theory (DFT, including the perturbation theory DFPT) within the screened coulomb hybrid (HSE06) exchange-correlation formalism. Among the various explored self-defective structures, a strong stabilization is obtained for the configuration displaying a direct interaction between the created N- and Ta-vacancies. In the lowest-energy structure, each of the three created Ta-vacancies and the five created N-vacancies is found to be in aggregated disposition, leading to the formation of cages into the lattice. Although the calculated structural, electronic, and optical properties of the two materials are found to be very similar and in good agreement with available experimental works, their photocatalytic features for visible-light overall water splitting reactions show completely different behaviors. On the basis of calculated band edge positions relative to water redox potentials, the perfect Ta3N5 (calculated band gap of 2.2 eV) is predicted by HSE06 to be a good candidate only for H+ reduction while the self-defective Ta3N5 (calculated band gap of 2.0 eV) reveals suitable band positions for both water oxidation and H+ reduction similar to the experimental data reported on Ta3N5 powders. Its ability to reduce H+ is predicted to be lower than the perfect one. However, the strongly localized electronic characters of the valence band (VB) and conduction band (CB) edge states of the self-defective material only on the N 2p and Ta 5d orbitals surrounding the aggregated N- and Ta-vacancies are expected to strongly limit the probability of photogenerated carrier mobility through its crystal structure.
Room temperature Coulomb blockade mediated field emission via self-assembled gold nanoparticles
Wang, Fei; Fang, Jingyue; Chang, Shengli; Qin, Shiqiao; Zhang, Xueao; Xu, Hui
2017-02-01
Coulomb blockade mediated field-emission current was observed in single-electron tunneling devices based on self-assembled gold nanoparticles at 300 K. According to Raichev's theoretical model, by fixing a proper geometric distribution of source, island and drain, the transfer characteristics can be well explained through a combination of Coulomb blockade and field emission. Coulomb blockade and field emission alternately happen in our self-assembled devices. The Coulomb island size derived from the experimental data is in good agreement with the average size of the gold nanoparticles used in the device. The integrated tunneling can be adjusted via a gate electrode.
Sota, Shigetoshi; Tohyama, Takami; Brazovskii, Serguei
2012-02-01
The optical response of organic compounds has been attracting much attention. The one of the reasons is the huge non-linear and ultrafast optical response [K. Yamamoto et. al., J. Phys. Soc. Jpn. 77, 074709(2008)]. In order to investigate such optical properties, we carry out dynamical DMRG calculations to obtain optical responses in the 1/4-filled one-dimensional Hubbard model including the nearest neighbor Coulomb interaction and the alternating electron hopping. The charge gap [S. Nishimoto, M. Takahashi, and Y. Ohta, J. Phys. Soc. Jpn. 69, 1594(2000)] and the bound state [H. Benthien and E. Jeckelmann, Eur. Phys. J. B 44, 287(2005)] in this model have been discussed based on DMRG calculations. In the present study, we introduce an alternating on-site potential giving the polarization in the system into the dimerized Hubbard model, which breaks the reflection symmetry of the system. In this talk, we discuss the obtained linear and the 2nd order non-linear optical susceptibility in order to make a prediction for non-linear optical experiments in the future.
Energy Technology Data Exchange (ETDEWEB)
Sugawara, M. [Chiba Institute of Technology, Narashino, Chiba 275-0023 (Japan); Toh, Y.; Oshima, M.; Hayakawa, T.; Hatsukawa, Y.; Katakura, J.; Shinohara, N.; Matsuda, M. [Japan Atomic Energy Research Institute, Tokai, Ibaraki 319-1195 (Japan); Czosnyka, T. [Heavy Ion Laboratory, Warsaw University, Warsaw PL-02097 (Poland); Kusakari, H. [Chiba University, Inage-ku, Chiba 263-8522 (Japan); Morikawa, T. [Kyushu University, Hakozaki, Fukuoka 812-8581 (Japan); Seki, A.; Sakata, F. [Department of Mathematical Sciences, Ibaraki University, Mito, Ibaraki 310-8512 (Japan)
2003-03-01
Electromagnetic properties of the low-lying states in a {sup 70}Ge nucleus were studied through the multiple Coulomb excitation of a {sup 70}Ge beam with a {sup nat}Pb target. Relative {gamma}-ray intensities were measured as a function of emission angle relative to the scattered projectile. Sixteen E2 matrix elements, including diagonal ones, for 6 low-lying states have been determined using the least-squares search code GOSIA. The expectation values left angle Q{sup 2} right angle of 0{sub 1}{sup +} and 0{sub 2}{sup +} states in {sup 70}Ge are compared with those in {sup 72,} {sup 74,} {sup 76}Ge. Simple mixing calculations indicate that the 0 {sub 2}{sup +} states in {sup 70}Ge and {sup 72}Se can be treated as deformed intruder states. It is shown that the deformed intruder becomes the ground state in {sup 74}Kr. These interpretations of the 0 {sub 2}{sup +} states in this region are compared with the potential-energy surface calculations by the Nilsson-Strutinsky model, which allow to interpret the experimental results in a qualitative way from the theoretical point of view. (orig.)
A New Efficient Method for Calculation of Frenkel Exciton Parameters in Molecular Aggregates
Plötz, Per-Arno; Kühn, Oliver
2013-01-01
The Frenkel exciton Hamiltonian is at the heart of many simulations of excitation energy transfer in molecular aggregates. It separates the aggregate into Coulomb-coupled monomers. Here it is shown that the respective parameters, i.e. monomeric excitation energies and Coulomb couplings between transition densities, can be efficiently calculated using time-dependent tight-binding-based density functional theory (TD-DFTB). Specifically, Coulomb couplings are expressed in terms of self-consistently determined Mulliken transition charges. The determination of the sign of the coupling requires an additional super-molecule calculation. The approach is applied to two dimer systems. First, formaldehyde oxime for which a detailed comparison with standard DFT using the B3LYP and the PBE functionals is provided. Second, the Coulomb coupling is explored in dependence on the intermolecular coordinates for a perylene bisimide dimer. This provides structural evidence for the previously observed biphasic aggregation behavior...
Interatomic Coulombic decay cascades in multiply excited neon clusters
Nagaya, K.; Iablonskyi, D.; Golubev, N. V.; Matsunami, K.; Fukuzawa, H.; Motomura, K.; Nishiyama, T.; Sakai, T.; Tachibana, T.; Mondal, S.; Wada, S.; Prince, K. C.; Callegari, C.; Miron, C.; Saito, N.; Yabashi, M.; Demekhin, Ph. V.; Cederbaum, L. S.; Kuleff, A. I.; Yao, M.; Ueda, K.
2016-01-01
In high-intensity laser light, matter can be ionized by direct multiphoton absorption even at photon energies below the ionization threshold. However on tuning the laser to the lowest resonant transition, the system becomes multiply excited, and more efficient, indirect ionization pathways become operative. These mechanisms are known as interatomic Coulombic decay (ICD), where one of the species de-excites to its ground state, transferring its energy to ionize another excited species. Here we show that on tuning to a higher resonant transition, a previously unknown type of interatomic Coulombic decay, intra-Rydberg ICD occurs. In it, de-excitation of an atom to a close-lying Rydberg state leads to electron emission from another neighbouring Rydberg atom. Moreover, systems multiply excited to higher Rydberg states will decay by a cascade of such processes, producing even more ions. The intra-Rydberg ICD and cascades are expected to be ubiquitous in weakly-bound systems exposed to high-intensity resonant radiation. PMID:27917867
Coulomb Impurity Potential RbCl Quantum Pseudodot Qubit
Ma, Xin-Jun; Qi, Bin; Xiao, Jing-Lin
2015-08-01
By employing a variational method of Pekar type, we study the eigenenergies and the corresponding eigenfunctions of the ground and the first-excited states of an electron strongly coupled to electron-LO in a RbCl quantum pseudodot (QPD) with a hydrogen-like impurity at the center. This QPD system may be used as a two-level quantum qubit. The expressions of electron's probability density versus time and the coordinates, and the oscillating period versus the Coulombic impurity potential and the polaron radius have been derived. The investigated results indicate ① that the probability density of the electron oscillates in the QPD with a certain oscillating period of , ② that due to the presence of the asymmetrical potential in the z direction of the RbCl QPD, the electron probability density shows double-peak configuration, whereas there is only one peak if the confinement is a two-dimensional symmetric structure in the xy plane of the QPD, ③ that the oscillation period is a decreasing function of the Coulombic impurity potential, whereas it is an increasing one of the polaron radius.
Coulomb effects on pions produced in heavy-ion reactions
Energy Technology Data Exchange (ETDEWEB)
Sullivan, J.P.
1981-11-01
Double differential cross sections for the production of ..pi../sup +/ and ..pi../sup -/ near the velocity of the incident beam for pion lab angles less than 40 degrees are presented. The experimental apparatus and the techniques are discussed. Beams of /sup 20/Ne with E/A from 80 to 655 MeV and /sup 40/Ar with E/A = 535 MeV incident on Be, C, NaF, KC1, Cu, and U targets were used. A sharp peak in the ..pi../sup -/ spectrum and a depression in the ..pi../sup +/ spectrum were observed at zero degrees near the incident beam velocity. The effect is explained in terms of Coulomb interactions between the pions and fragments of the incident beam. Least squares fits to the data using the Coulomb correction formulas of Gyulassy and Kauffman and an effective projectile fragment charge are made. The relationship between these data and previously measured pion production and projectile fragmentation data is discussed. The data are also compared to some theoretical models. A simple expression is given for the differential cross section as a function of the projectile mass, target mass, and beam energy.
Super-Coulombic atom-atom interactions in hyperbolic media
Cortes, Cristian L.; Jacob, Zubin
2017-01-01
Dipole-dipole interactions, which govern phenomena such as cooperative Lamb shifts, superradiant decay rates, Van der Waals forces and resonance energy transfer rates, are conventionally limited to the Coulombic near-field. Here we reveal a class of real-photon and virtual-photon long-range quantum electrodynamic interactions that have a singularity in media with hyperbolic dispersion. The singularity in the dipole-dipole coupling, referred to as a super-Coulombic interaction, is a result of an effective interaction distance that goes to zero in the ideal limit irrespective of the physical distance. We investigate the entire landscape of atom-atom interactions in hyperbolic media confirming the giant long-range enhancement. We also propose multiple experimental platforms to verify our predicted effect with phonon-polaritonic hexagonal boron nitride, plasmonic super-lattices and hyperbolic meta-surfaces as well. Our work paves the way for the control of cold atoms above hyperbolic meta-surfaces and the study of many-body physics with hyperbolic media.
Coulomb dissociation reactions on molybdenum isotopes for astrophysics applications
Energy Technology Data Exchange (ETDEWEB)
Ershova, Olga
2012-03-09
Within the present work, photodissociation reactions on {sup 100}Mo, {sup 93}Mo and {sup 92}Mo isotopes were studied by means of the Coulomb dissociation method at the LAND setup at GSI. As a result of the analysis of the present experiment, integrated Coulomb excitation cross sections of the {sup 100}Mo({gamma},n), {sup 100}Mo({gamma},2n), {sup 93}Mo({gamma},n) and {sup 92}Mo({gamma},n) reactions were determined. A second important topic of the present thesis is the investigation of the efficiency of the CsI gamma detector. The data taken with the gamma calibration sources shortly after the experiment were used for the investigation. In addition, a test experiment in refined conditions was conducted within the framework of this thesis. Numerous GEANT3 simulations of the detector were performed in order to understand various aspects of its performance. As a result, the efficiency of the detector was determined to be approximately a factor of 2 lower than the efficiency expected from the simulation. (orig.)
Revealing the Coulomb interaction strength in a cuprate superconductor
Yang, S.-L.; Sobota, J. A.; He, Y.; Wang, Y.; Leuenberger, D.; Soifer, H.; Hashimoto, M.; Lu, D. H.; Eisaki, H.; Moritz, B.; Devereaux, T. P.; Kirchmann, P. S.; Shen, Z.-X.
2017-12-01
We study optimally doped Bi2Sr2Ca0.92Y0.08Cu2O8 +δ (Bi2212) using angle-resolved two-photon photoemission spectroscopy. Three spectral features are resolved near 1.5, 2.7, and 3.6 eV above the Fermi level. By tuning the photon energy, we determine that the 2.7-eV feature arises predominantly from unoccupied states. The 1.5- and 3.6-eV features reflect unoccupied states whose spectral intensities are strongly modulated by the corresponding occupied states. These unoccupied states are consistent with the prediction from a cluster perturbation theory based on the single-band Hubbard model. Through this comparison, a Coulomb interaction strength U of 2.7 eV is extracted. Our study complements equilibrium photoemission spectroscopy and provides a direct spectroscopic measurement of the unoccupied states in cuprates. The determined Coulomb U indicates that the charge-transfer gap of optimally doped Bi2212 is 1.1 eV.
Coulomb excitation of the odd-odd isotopes $^{106, 108}$In
Ekstrom, A; Blazhev, A; Van de Walle, J; Weisshaar, D; Zielinska, M; Tveten, G M; Marsh, B A; Siem, S; Gorska, M; Engeland, T; Hurst, A M; Cederkall, J; Finke, F; Iwanicki, J; Hjorth-Jensen, M; Davinson, T; Eberth, J; Sletten, G; Mierzejewski, J; Reiter, P; Warr, N; Butler, P A; Fahlander, C; Stefanescu, I; Koester, U; Ivanov, O; Wenander, F; Voulot, D
2010-01-01
The low-lying states in the odd-odd and unstable isotopes In-106,In-108 have been Coulomb excited from the ground state and the first excited isomeric state at the REX-ISOLDE facility at CERN. With the additional data provided here the pi g(9/2)(-1) circle times nu d(5/2) and pi g(9/2)(-1) circle times nu g7/2 multiplets have been re-analyzed and are modified compared to previous results. The observed gamma-ray de-excitation patterns were interpreted within a shell model calculation based on a realistic effective interaction. The agreement between theory and experiment is satisfactory and the calculations reproduce the observed differences in the excitation pattern of the two isotopes. The calculations exclude a 6(+) ground state in In-106. This is in agreement with the conclusions drawn using other techniques. Furthermore, based on the experimental results, it is also concluded that the ordering of the isomeric and ground state in In-108 is inverted compared to the shell model prediction. Limits on B(E2) val...
Burgess, C. P.; Hayman, Peter; Rummel, Markus; Williams, Matt; Zalavári, László
2017-07-01
We apply point-particle effective field theory (PPEFT) to compute the leading shifts due to finite-sized source effects in the Coulomb bound energy levels of a relativistic spinless charged particle. This is the analogue for spinless electrons of calculating the contribution of the charge-radius of the source to these levels, and our calculation disagrees with standard calculations in several ways. Most notably we find there are two effective interactions with the same dimension that contribute to leading order in the nuclear size, one of which captures the standard charge-radius contribution. The other effective operator is a contact interaction whose leading contribution to δE arises linearly (rather than quadratically) in the small length scale, ɛ, characterizing the finite-size effects, and is suppressed by ( Zα)5. We argue that standard calculations miss the contributions of this second operator because they err in their choice of boundary conditions at the source for the wave-function of the orbiting particle. PPEFT predicts how this boundary condition depends on the source's charge radius, as well as on the orbiting particle's mass. Its contribution turns out to be crucial if the charge radius satisfies ɛ ≲ ( Zα)2 a B , where a B is the Bohr radius, because then relativistic effects become important for the boundary condition. We show how the problem is equivalent to solving the Schrödinger equation with competing Coulomb, inverse-square and delta-function potentials, which we solve explicitly. A similar enhancement is not predicted for the hyperfine structure, due to its spin-dependence. We show how the charge-radius effectively runs due to classical renormalization effects, and why the resulting RG flow is central to predicting the size of the energy shifts (and is responsible for its being linear in the source size). We discuss how this flow is relevant to systems having much larger-than-geometric cross sections, such as those with large
Boschini, M.J.; Gervasi, M.; Giani, S.; Grandi, D.; Ivantchenko, V.; Pensotti, S.; Rancoita, P.G.; Tacconi, M.
2011-01-01
In the space environment, instruments onboard of spacecrafts can be affected by displacement damage due to radiation. The differential scattering cross section for screened nucleus--nucleus interactions - i.e., including the effects due to screened Coulomb nuclear fields -, nuclear stopping powers and non-ionization energy losses are treated from about 50\\,keV/nucleon up to relativistic energies.
Suzumura, Yoshikazu
2018-02-01
The nuclear magnetic resonance (NMR) shift, χα, at low temperatures is examined for massless Dirac electrons in the organic conductor, α-(BEDT-TTF)2I3, where α [= A (= A'), B, and C] denotes the sites of the four molecules in the unit cell. The Dirac cone exists within an energy of 0.01 eV between the conduction and valence bands. The magnetic response function is calculated by taking account of the long-range Coulomb interaction and electron doping. Calculating the interaction within the first order in the perturbation, the chemical potential is determined self-consistently, and the self-energy and vertex corrections are taken to satisfy the Ward identity. The site-dependent χα is calculated at low temperatures of 0.0002 χ B. The relevance of the shift to the experiment is discussed.
Electron self-energy calculation using a general multi-pole approximation
Soininen, J A; Shirley, E L
2003-01-01
We present a method for calculating the inverse of the dielectric matrix in a solid using a band Lanczos algorithm. The method produces a multi-pole approximation for the inverse dielectric matrix with an arbitrary number of poles. We discuss how this approximation can be used to calculate the screened Coulomb interaction needed for electron self-energy calculations in solids.
Efficient Finite Element Calculation of Ny
DEFF Research Database (Denmark)
Clausen, Johan; Damkilde, Lars; Krabbenhøft, K.
2007-01-01
The performance of a return mapping scheme for plasticity with linear yield planes in principal stress space is evaluated in relation to a Mohr-Coulomb material. For purely frictional materials this material model is known to cause problems in numerical calculations, but these problems are not ex...
Directory of Open Access Journals (Sweden)
Xu Cheng
2016-09-01
Full Text Available Abstract After M W 7.8 Nepal earthquake occurred, the rearrangement of stresses in the crust commonly leads to subsequent damaging earthquakes. We present the calculations of the coseismic stress changes that resulted from the 25th April event using models of regional faults designed according to south Tibet-Nepal structure, and show that some indicative significant stress increases. We calculate static stress changes caused by the displacement of a fault on which dislocations happen and an earthquake occurs. A M W 7.3 earthquake broke on 12 May at a distance of ~ 130 km SEE of the M W 7.8 earthquake, whose focus roughly located on high Coulomb stress change (CSC site. Aftershocks (first 15 days after the mainshock are associated with stress increase zone caused by the main rupture. We set receiver faults with specified strikes, dips, and rakes, on which the stresses imparted by the source fault are resolved. Four group normal faults to the north of the Nepal earthquake seismogenic fault were set as receiver faults and variant results followed. We provide a discussion on Coulomb stress transfer for the seismogenic fault, which is useful to identify potential future rupture zones.
Gribov horizon and the one-loop color-Coulomb potential
DEFF Research Database (Denmark)
Golterman, Maarten; Greensite, Jeffrey Paul; Peris, Santiago
2012-01-01
We recalculate the color-Coulomb potential to one-loop order, under the assumption that the effect of the Gribov horizon is to make (i) the transverse gluon propagator less singular and (ii) the color-Coulomb potential more singular than their perturbative behavior in the low-momentum limit...
A Simple And Efficient FEM-Implementation Of The Modified Mohr-Coulomb Criterion
DEFF Research Database (Denmark)
Clausen, Johan Christian; Damkilde, Lars
2006-01-01
This paper presents a conceptually simple finite element implementation of the combined elasto-plastic Mohr-Coulomb and Rankine material models, also known as Modified Mohr-Coulomb plasticity. The stress update is based on a return mapping scheme where all manipulations are carried out in princip...
Coulomb Interaction Effect in Weyl Fermions with Tilted Energy Dispersion in Two Dimensions
Isobe, Hiroki; Nagaosa, Naoto
2016-03-01
Weyl fermions with tilted linear dispersions characterized by several different velocities appear in some systems including the quasi-two-dimensional organic semiconductor α -(BEDT -TTF )2I3 and three-dimensional WTe2 . The Coulomb interaction between electrons modifies the velocities in an essential way in the low-energy limit, where the logarithmic corrections dominate. Taking into account the coupling to both the transverse and longitudinal electromagnetic fields, we derive the renormalization group equations for the velocities of the tilted Weyl fermions in two dimensions, and found that they increase as the energy decreases and eventually hit the speed of light c to result in the Cherenkov radiation. Especially, the system restores the isotropic Weyl cone even when the bare Weyl cone is strongly tilted and the velocity of electrons becomes negative in certain directions.
Energy Technology Data Exchange (ETDEWEB)
Zielinska, M. [CEA Saclay, IRFU/SPhN, Gif-sur-Yvette (France); Gaffney, L.P. [KU Leuven, Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); University of the West of Scotland, School of Engineering, Paisley (United Kingdom); Wrzosek-Lipska, K. [KU Leuven, Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); University of Warsaw, Heavy Ion Laboratory, Warsaw (Poland); Clement, E. [GANIL, Caen Cedex (France); Grahn, T.; Pakarinen, J. [University of Jyvaskylae, Department of Physics, Jyvaskylae (Finland); University of Helsinki, Helsinki Institute of Physics, Helsinki (Finland); Kesteloot, N. [KU Leuven, Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); SCK-CEN, Belgian Nuclear Research Centre, Mol (Belgium); Napiorkowski, P. [University of Warsaw, Heavy Ion Laboratory, Warsaw (Poland); Duppen, P. van [KU Leuven, Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); Warr, N. [Technische Universitaet Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany)
2016-04-15
With the recent advances in radioactive ion beam technology, Coulomb excitation at safe energies becomes an important experimental tool in nuclear-structure physics. The usefulness of the technique to extract key information on the electromagnetic properties of nuclei has been demonstrated since the 1960s with stable beam and target combinations. New challenges present themselves when studying exotic nuclei with this technique, including dealing with low statistics or number of data points, absolute and relative normalisation of the measured cross-sections and a lack of complementary experimental data, such as excited-state lifetimes and branching ratios. This paper addresses some of these common issues and presents analysis techniques to extract transition strengths and quadrupole moments utilising the least-squares fit code, GOSIA. (orig.)
Statistical mechanics of Coulomb gases as quantum theory on Riemann surfaces
Gulden, Tobias; Janas, Michael; Kamenev, Alex
2014-03-01
Statistical mechanics of 1D Coulomb gases may be mapped onto (in general) non-Hermitian quantum mechanics. We use this example to develop non-Hermitian instanton calculus. Treating momentum and coordinate as independent complex variables, constant energy manifolds are given by Riemann surfaces of genus g >= 1 . The actions along principal cycles on these surfaces obey an ODE in the moduli space of the Riemann surface known as the Picard-Fuchs equation. Solving the Picard-Fuchs equation yields semiclassical spectra as well as instanton effects such as width of Bloch bands (the latter determines energy barrier for charge transport). Both are shown to be in perfect agreement with numerical simulations. Applications include transport through biological ion channels as well as nanofluidics, e.g water filled nanotubes. The work was supported by NSF grant DMR1306734.
Linear-response theory of Coulomb drag in coupled electron systems
DEFF Research Database (Denmark)
Flensberg, Karsten; Hu, Ben Yu-Kuang; Jauho, Antti-Pekka
1995-01-01
We report a fully microscopic theory for the transconductivity, or, equivalently, the momentum transfer rate, of Coulomb coupled electron systems. We use the Kubo linear-response formalism and our main formal result expresses the transconductivity in terms of two fluctuation diagrams, which...... are topologically related but not equivalent to the Aslamazov-Larkin diagrams known from superconductivity. Results reported elsewhere are shown to be special cases of our general expression; specifically, we recover the Boltzmann equation result in the semiclassical clean limit and the memory function results...... for dirty systems with constant impurity scattering rates. Furthermore, we show that for energy-dependent relaxation times, the final result is not expressible in terms of standard density-response functions. Other results include (i) at T = 0, the frequency dependence of the transfer rate is found...
Ultra-high-ohmic microstripline resistors for Coulomb blockade devices
Lotkhov, Sergey V.
2013-06-01
In this paper, we report on the fabrication and low-temperature characterization of ultra-high-ohmic microstripline resistors made of a thin film of weakly oxidized titanium. Nearly linear voltage-current characteristics were measured at temperatures down to T ˜ 20 mK for films with sheet resistivities as high as ˜7 kΩ, i.e. about an order of magnitude higher than our previous findings for weakly oxidized Cr. Our analysis indicates that such an improvement can help to create an advantageous high-impedance environment for different Coulomb blockade devices. Further properties of the Ti film addressed in this work show the promise of low-noise behavior of the resistors when applied in different realizations of the quantum standard of current.
Coulomb impurity scattering in topological insulator thin films
Energy Technology Data Exchange (ETDEWEB)
Yin, Gen; Wickramaratne, Darshana; Lake, Roger K., E-mail: rlake@ee.ucr.edu [Department of Electrical Engineering, University of California, Riverside, California 92521 (United States); Zhao, Yuanyuan [Texas Center for Superconductivity and Department of Physics, University of Houston, Houston, Texas 77204 (United States)
2014-07-21
Inter-surface coupling in thin-film topological insulators can reduce the surface state mobility by an order of magnitude in low-temperature transport measurements. The reduction is caused by a reduction in the group velocity and an increased s{sub z} component of the surface-state spin which weakens the selection rule against large-angle scattering. An intersurface potential splits the degenerate bands into a Rashba-like bandstructure. This reduces the intersurface coupling, it largely restores the selection rule against large angle scattering, and the ring-shaped valence band further reduces backscattering by requiring, on average, larger momentum transfer for backscattering events. The effects of temperature, Fermi level, and intersurface potential on the Coulomb impurity scattering limited mobility are analyzed and discussed.
Coulomb-gas approach for boundary conformal field theory
Energy Technology Data Exchange (ETDEWEB)
Kawai, Shinsuke E-mail: kawai@thphys.ox.ac.uk
2002-05-20
We present a construction of boundary states based on the Coulomb-gas formalism of Dotsenko and Fateev. It is shown that Neumann-like coherent states on the charged bosonic Fock space provide a set of boundary states with consistent modular properties. Such coherent states are characterised by the boundary charges, which are related to the number of bulk screening operators through the charge neutrality condition. We illustrate this using the Ising model as an example, and show that all of its known consistent boundary states are reproduced in our formalism. This method applies to c<1 minimal conformal theories and provides an unified computational tool for studying boundary states of such theories.
The Coulomb Branch Formula for Quiver Moduli Spaces
Manschot, Jan; Sen, Ashoke
2014-01-01
In recent series of works, by translating properties of multi-centered supersymmetric black holes into the language of quiver representations, we proposed a formula that expresses the Hodge numbers of the moduli space of semi-stable representations of quivers with generic superpotential in terms of a set of invariants associated to `single-centered' or `pure-Higgs' states. The distinguishing feature of these invariants is that they are independent of the choice of stability condition. Furthermore they are uniquely determined by the $\\chi_y$-genus of the moduli space. Here, we provide a self-contained summary of the Coulomb branch formula, spelling out mathematical details but leaving out proofs and physical motivations.
Imaging of Coulomb-Driven Quantum Hall Edge States
Lai, Keji
2011-10-01
The edges of a two-dimensional electron gas (2DEG) in the quantum Hall effect (QHE) regime are divided into alternating metallic and insulating strips, with their widths determined by the energy gaps of the QHE states and the electrostatic Coulomb interaction. Local probing of these submicrometer features, however, is challenging due to the buried 2DEG structures. Using a newly developed microwave impedance microscope, we demonstrate the real-space conductivity mapping of the edge and bulk states. The sizes, positions, and field dependence of the edge strips around the sample perimeter agree quantitatively with the self-consistent electrostatic picture. The evolution of microwave images as a function of magnetic fields provides rich microscopic information around the ν=2 QHE state. © 2011 American Physical Society.
Gravitational Modification of the Coulomb-Breit Hamiltonian
Caicedo, José Alexander; Urrutia, Luis Fernando
2009-04-01
In the poster session we presented a short review of our first results in the construction of the Coulomb-Breit Hamiltonian for a pair of fermions immersed in a background gravitational field which is described by General Relativity. Here we present a resume of that construction. We make a special stress on the objectives and the hypothesis used, but there is no special attention on the explicit form of the results because actually there is an updated and optimised version of our work in the edition process for publication; however we mention some special characteristics of the effect of the background gravitational field on the quantum nature of the system composed by fermions and its electromagnetic field, particularly the possibility of the observation of centre of mass effects in matter interferometry experiments.
Quantum mechanics on phase space and the Coulomb potential
Campos, P.; Martins, M. G. R.; Vianna, J. D. M.
2017-04-01
Symplectic quantum mechanics (SMQ) makes possible to derive the Wigner function without the use of the Liouville-von Neumann equation. In this formulation of the quantum theory the Galilei Lie algebra is constructed using the Weyl (or star) product with Q ˆ = q ⋆ = q +iħ/2∂p , P ˆ = p ⋆ = p -iħ/2∂q, and the Schrödinger equation is rewritten in phase space; in consequence physical applications involving the Coulomb potential present some specific difficulties. Within this context, in order to treat the Schrödinger equation in phase space, a procedure based on the Levi-Civita (or Bohlin) transformation is presented and applied to two-dimensional (2D) hydrogen atom. Amplitudes of probability in phase space and the correspondent Wigner quasi-distribution functions are derived and discussed.
Electric and Magnetic Coulomb Potentials in the Deuteron
Directory of Open Access Journals (Sweden)
Bernard Schaeffer
2013-09-01
Full Text Available After one century of nuclear physics, the underlying fun- damental laws of nuclear physics are still missing. Bohr had found a formula for the H atom and another for the H2 molecule but no equivalent formula exists for the deuteron 2H. The only known Coulomb interaction in a nucleus by the mainstream nuclear physics is the long range repulsion between protons, forgetting that the neutron contains elec- tric charges with no net charge. The neutron is attracted by the proton in a way discovered two millenaries ago by the Greeks. This attraction is equilibrated by the repulsion between the opposite magnetic moments of the proton and of the neutron in the deuteron. The bare application of ge- ometry together with electric and magnetic Coulomb’s in- teractions accounts for the binding energy of the deuteron, without fitting, with only 4 per cent discrepancy, proving the electromagnetic nature of the nuclear energy.
National Oceanic and Atmospheric Administration, Department of Commerce — Declination is calculated using the current International Geomagnetic Reference Field (IGRF) model. Declination is calculated using the current World Magnetic Model...
Coulomb excitation of doubly magic $^{132}$Sn with MINIBALL at HIE-ISOLDE
We propose to study the vibrational first 2$^{+}$ and 3$^{-}$ states of the doubly magic nucleus $^{132}$ Sn via Coulomb excitation using the HIE-ISOLDE facility coupled with the highly efficient MINIBALL array. The intense $^{132}$Sn beam at ISOLDE, the high beam energy of HIE-ISOLDE, the high energy resolution and good efficiency of the MINIBALL provide a unique combination and favourable advantages to master this demanding measurement. Reliable B(E2;0$^{+}\\rightarrow$ 2$^{+}$) values for neutron deficient $^{106,108,110}$Sn were obtained with the MINIBALL at REX-ISOLDE. These measurements can be extended up to and beyond the shell closure at the neutron-rich side with $^{132}$Sn. The results on excited collective states in $^{132}$Sn will provide crucial information on 2p-2h cross shell configurations which are expected to be dominated by a strong proton contribution. Predictions are made within various large scale shell model calculations and new mean field calculations within the framework of different a...
Santhosh, K. P.; Sukumaran, Indu
2017-09-01
Half-life predictions have been performed for the proton emitters with Z >50 in the ground state and isomeric state using the Coulomb and proximity potential model for deformed nuclei (CPPMDN). The agreement of the calculated values with the experimental data made it possible to predict some proton emissions that are not verified experimentally yet. For a comparison, the calculations also are performed using other theoretical models, such as the Gamow-like model of Zdeb et al. [Eur. Phys. J. A 52, 323 (2016), 10.1140/epja/i2016-16323-7], the semiempirical relation of Hatsukawa et al. [Phys. Rev. C 42, 674 (1990), 10.1103/PhysRevC.42.674], and the CPPM of Santhosh et al. [Pramana 58, 611 (2002)], 10.1007/s12043-002-0019-2. The Geiger-Nuttall law, originally observed for α decay, studied for proton radioactivity is found to work well provided it is plotted for the isotopes of a given proton emitter nuclide with the same ℓ value. The universal curve is found to be valid for proton radioactivity also as we obtained a single straight line for all proton emissions irrespective of the parents. Through the analysis of the experimentally measured half-lives of 44 proton emitters, the study revealed that the present systematic study lends support to a unified description for studying α decay, cluster radioactivity, and proton radioactivity.
Recent developments in heavy-ion fusion reactions around the Coulomb barrier
Directory of Open Access Journals (Sweden)
Hagino K.
2016-01-01
Full Text Available The nuclear fusion is a reaction to form a compound nucleus. It plays an important role in several circumstances in nuclear physics as well as in nuclear astrophysics, such as synthesis of superheavy elements and nucleosynthesis in stars. Here we discuss two recent theoretical developments in heavy-ion fusion reactions at energies around the Coulomb barrier. The first topic is a generalization of the Wong formula for fusion cross sections in a single-channel problem. By introducing an energy dependence to the barrier parameters, we show that the generalized formula leads to results practically indistinguishable from a full quantal calculation, even for light symmetric systems such as 12C+12C, for which fusion cross sections show an oscillatory behavior. We then discuss a semi-microscopic modeling of heavy-ion fusion reactions, which combine the coupled-channels approach to the state-of-the-art nuclear structure calculations for low-lying collective motions. We apply this method to subbarrier fusion reactions of 58Ni+58Ni and 40Ca+58Ni systems, and discuss the role of anharmonicity of the low-lying vibrational motions.
Solving the three-body Coulomb breakup problem using exterior complex scaling
Energy Technology Data Exchange (ETDEWEB)
McCurdy, C.W.; Baertschy, M.; Rescigno, T.N.
2004-05-17
Electron-impact ionization of the hydrogen atom is the prototypical three-body Coulomb breakup problem in quantum mechanics. The combination of subtle correlation effects and the difficult boundary conditions required to describe two electrons in the continuum have made this one of the outstanding challenges of atomic physics. A complete solution of this problem in the form of a ''reduction to computation'' of all aspects of the physics is given by the application of exterior complex scaling, a modern variant of the mathematical tool of analytic continuation of the electronic coordinates into the complex plane that was used historically to establish the formal analytic properties of the scattering matrix. This review first discusses the essential difficulties of the three-body Coulomb breakup problem in quantum mechanics. It then describes the formal basis of exterior complex scaling of electronic coordinates as well as the details of its numerical implementation using a variety of methods including finite difference, finite elements, discrete variable representations, and B-splines. Given these numerical implementations of exterior complex scaling, the scattering wave function can be generated with arbitrary accuracy on any finite volume in the space of electronic coordinates, but there remains the fundamental problem of extracting the breakup amplitudes from it. Methods are described for evaluating these amplitudes. The question of the volume-dependent overall phase that appears in the formal theory of ionization is resolved. A summary is presented of accurate results that have been obtained for the case of electron-impact ionization of hydrogen as well as a discussion of applications to the double photoionization of helium.
Wu, Chengyin; Wu, Cong; Song, Di; Su, Hongmei; Xie, Xiguo; Li, Min; Deng, Yongkai; Liu, Yunquan; Gong, Qihuang
2014-04-14
We experimentally reconstructed the structure of the N2Ar van der Waals complex with the technique of laser-based channel-selected Coulomb explosion imaging. The internuclear distance between the N2 center of mass and the Ar atom, i.e., the length of the van der Waals bond, was determined to be 3.88 Å from the two-body explosion channels. The angle between the van der Waals bond and the N2 principal axis was determined to be 90° from the three-body explosion channels. The reconstructed structure was contrasted with our high level ab initio calculations. The agreement demonstrated the potential application of laser-based Coulomb explosion in imaging transient molecular structure, particularly for floppy van der Waals complexes, whose structures remain difficult to be determined by conventional spectroscopic methods.
Oryu, S.; Watanabe, T.; Hiratsuka, Y.; Kodama, A.; Togawa, Y.; Takeda, M.
2017-10-01
We propose an off-shell Coulomb-like amplitude with an on-shell phase shift that is accurate to within 9-10 digits. The full Coulomb amplitude is separated into the leading and the auxiliary amplitudes using “the two-potential theory”. The leading amplitude reproduces most of the on- and off-shell parts, while the auxiliary amplitude contributes mainly to the off-shell part and minimally to the on-shell part. We then review the three-body calculation method developed during the last four decades. A reminder to a threshold behavior investigation method is pointed out based on the three-body Faddeev equation. We discuss the Efimov physics and some extensions, which are recovered from our predictions. The method may suggest a promising technique to resolve the existing discrepancies between current experimental and theoretical values.
Chattopadhyaya, Mausumi; Sen, Sabyasachi; Alam, Md. Mehboob; Chakrabarti, Swapan
2014-02-01
The present study deals with the relative performance of the various density functional approaches in evaluating the band gap of polymer materials. Several density functional approximations that includes pure generalized gradient approximated (GGA) functional, meta-GGA, hybrid and range separated hybrid functionals have been used to evaluate the electrical band gap or transport gap of the studied polymers and compared with that obtained using Hubbard U corrected GGA functional (GGA+U). It has been observed that the experimental band gap of the polymers studied is satisfactorily reproducible when GGA+U approach is adopted. The band gap analyses further suggest that range separated hybrid functional, CAM-B3LYP, largely overestimates the band gap of all the polymers studied while the performance of hybrid B3LYP functional and other range separated hybrid functional like HSE is moderate. Better performance of the GGA+U method clearly indicates that short range coulomb correlation plays more significant role over the non-local Hartree-Fock (HF) exchange in determining the electrical band gap of polymer materials. It is also noticeable that the Hubbard U parameter used for the various polymers under consideration is relatively large, indicating the semi-empirical nature of the GGA+U level of calculations. The present finding will help us design new low band gap polymer through estimating band gap by the GGA+U method and this could be very useful for solar cell research.
Energy Technology Data Exchange (ETDEWEB)
Mueller-Heuser, G. [Ministerium fuer Umwelt, Raumordnung und Landwirtschaft des Landes Nordrhein-Westfalen, Duesseldorf (Germany); Altmann, B.R. [Deutsche Wissenschaftliche Gesellschaft fuer Erdoel, Erdgas und Kohle e.V., Hamburg (Germany); Arp, J. [Staatliches Umweltamt, Itzehoe (Germany); Schoenwald, H. [Landesamt fuer Gesundheit und Arbeitssicherheit des Landes Schleswig-Holstein, Itzehoe (Germany)
2000-09-01
Since the publication of DGMK Research Report 499 in October 1977 the knowledge of the technology for cleaning cruide oil tanks has improved, so that it appears possible that emissions of hydrocarbons less than 0,5 kg/m2 tank bottom area, according to the attached calculation examples, can be achieved. Secondary measures for cleaning crude oil tanks are currently under development so that further emission reductions of hydrocarbons up to 90% of the remaining emissions from working and evaporating can be expected. By increasing installation of double bottoms and time extension with regard to the inside inspections the number of the annual crude oil tank cleaning procedures is decreasing. The follow up of DGMK-Research Report 499 extensively describes the questions of work protection. An additional important item is the information of relevant authorities with a special paper for instructions. (orig.) [German] Seit dem Erscheinen der Erstausgabe des DGMK-Forschungsberichtes 499 im Oktober 1997 hat sich der Stand der Rohoeltankreinigungstechnik fortentwickelt, so dass Emissionen an Kohlenwasserstoffen {<=}0,5 kg je m{sup 2} Tankbodenflaeche nach den anliegenden Berechnungsbeispielen sicher einhaltbar erscheinen. Sekundaermassnahmen bei der Rohoeltankreinigung befinden sich gegenwaertig in der Entwicklung und lassen eine weitere Minderung der Kohlenwasserstoffemissionen bis zu 90% der verbleibenden Emission aus Verdraengung und Belueftung erwarten. Durch den zunehmenden Einbau von Doppelboeden sowie Fristverlaengerung in Bezug auf die Innenbesichtigungspflichten sinkt die Zahl der jaehrlichen Rohoeltankreinigungen. In der Fortschreibung des DGMK-Forschungsberichtes 499 wird auf die Belange des Arbeitsschutzes ausfuehrlich eingegangen. Ein weiterer wesentlicher Punkt ist die Mitteilung an die zustaendigen Behoerden, fuer die ein Formblatt mit Hinweisen erarbeitet worden ist. (orig.)
Zheng, Na; Xu, Hai-Bo
2015-10-01
An empirical numerical model that includes nuclear absorption, multiple Coulomb scattering and energy loss is presented for the calculation of transmission through thick objects in high energy proton radiography. In this numerical model the angular distributions are treated as Gaussians in the laboratory frame. A Monte Carlo program based on the Geant4 toolkit was developed and used for high energy proton radiography experiment simulations and verification of the empirical numerical model. The two models are used to calculate the transmission fraction of carbon and lead step-wedges in proton radiography at 24 GeV/c, and to calculate radial transmission of the French Test Object in proton radiography at 24 GeV/c with different angular cuts. It is shown that the results of the two models agree with each other, and an analysis of the slight differences is given. Supported by NSAF (11176001) and Science and Technology Developing Foundation of China Academy of Engineering Physics (2012A0202006)
Reaction study of {sup 11}Li on {sup 208}Pb target at energies close the Coulomb barrier
Energy Technology Data Exchange (ETDEWEB)
Cubero, Mario; Jose Borge, Maria; Tengblad, Olof; Alcorta, Martin; Madurga, Miguel [Instituto de Estructura de la Materia, Madrid (Spain); Camacho, Joaquin [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, Sevilla (Spain); Martel, Ismael [Departamento de Fisica Aplicada, Universidad de Huelva, Huelva (Spain); Walden, Pat [TRI-University Meson Facilities, University of British Columbia, Vancouver (Canada)
2009-07-01
In the past 20 years there has been interest among the nuclear physics community to study the exotic properties observed in halo nuclei such as {sup 11}Li. Recent theoretical calculations predicted a deviation of the elastic cross section from the standard Rutherford formula, expected due to the dipole structure formed by the {sup 9}Li core and the halo neutrons when passing near the strong Coulomb produced by the Pb target. To explore this effect, the scattering and breakup reactions of the two-neutron halo nucleus {sup 11}Li were measured at ISACII-TRIUMF. Data was obtained at energies around, below and above the Coulomb barrier, 2.7 MeV/u. We used a set of four telescopes with PAD silicon detectors behind in order to clearly identified all fragments in the full detection angles covering 10-140 degree.In this contribution we present the analysis of the {sup 9}Li scattering data that it is needed to understand the effect on the {sup 11}Li cross sections. We also present preliminary results of the {sup 11}Li scattering.
Filippone, Michele; Mora, Christophe
2012-09-01
We formulate a general approach for studying the low-frequency response of an interacting quantum dot connected to leads in the presence of oscillating gate voltages. The energy dissipated is characterized by the charge relaxation resistance, which under the loose assumption of Fermi liquid behavior at low energy, is shown to depend only on static charge susceptibilities. The predictions of the scattering theory are recovered in the noninteracting limit while the effect of interactions is simply to replace densities of states by charge susceptibilities in formulas. In order to substantiate the Fermi liquid picture in the case of a quantum RC geometry, we apply a renormalization group analysis and derive the low-energy Hamiltonian for two specific models: the Anderson and the Coulomb blockade models. The Anderson model is shown, using a field theoretical approach based on Barnes slave bosons, to map onto the Kondo model. We recover the well-known expression of the Kondo temperature for the asymmetric Anderson model and compute the charge susceptibility. The Barnes slave bosons are extended to the Coulomb blockade model where the renormalization-group analysis can be carried out perturbatively up to zero energy. All calculations agree with the Fermi liquid nature of the low-energy fixed point and satisfy the Friedel sum rule.
Coulomb scatter of diamagnetic dust particles in a cusp magnetic trap under microgravity conditions
Energy Technology Data Exchange (ETDEWEB)
Myasnikov, M. I., E-mail: miasnikovmi@mail.ru; D’yachkov, L. G.; Petrov, O. F.; Vasiliev, M. M., E-mail: mixxy@mail.ru; Fortov, V. E. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Savin, S. F.; Serova, E. O. [Korolev Rocket and Space Corporation Energia, ul. Lenina 4A (Russian Federation)
2017-02-15
The effect of a dc electric field on strongly nonideal Coulomb systems consisting of a large number (~10{sup 4}) of charged diamagnetic dust particles in a cusp magnetic trap are carried out aboard the Russian segment of the International Space Station (ISS) within the Coulomb Crystal experiment. Graphite particles of 100–400 μm in size are used in the experiments. Coulomb scatter of a dust cluster and the formation of threadlike chains of dust particles are observed experimentally. The processes observed are simulated by the molecular dynamics (MD) method.
Scholten, Robert; Speirs, Rory; Murphy, Dene; Torrance, Joshua; Thompson, Daniel; Sparkes, Benjamin; McCulloch, Andrew
2017-04-01
The CAEIS cold-atom electron/ion source, based on photoionisation of laser cooled atoms, provides a powerful tool for investigating fundamental physical processes. The very low temperature of the ions has allowed us to image intra-beam Coulomb effects with unprecedented detail. With ultrafast laser excitation and streak detection we can probe competing ionization processes, particularly via Rydberg states, including sequential excitation, multiphoton excitation, resonance-enhanced multiphoton excitation and two-color multiphoton excitation. Knowledge from these studies has enabled ultrafast single-shot diffractive electron imaging with atomic resolution using a CAEIS.
DEFF Research Database (Denmark)
Ruban, Andrei; Simak, S.I.; Korzhavyi, P.A.
2002-01-01
A quantitative description of the configurational part of the total energy of metallic alloys with substantial atomic size difference cannot be achieved in the atomic-sphere approximation: It needs to be corrected at least for the multipole-moment interactions in the Madelung part of the one......-electron potential and energy. In the case of a random alloy such interactions can be accounted for only by lifting the atomic-sphere and single-site approximations, in order to include the polarization due to local environment effects. Nevertheless, a simple parametrization of the screened Coulomb interactions...
Efficient Algorithms for Electrostatic Interactions Including Dielectric Contrasts
Directory of Open Access Journals (Sweden)
Christian Holm
2013-10-01
Full Text Available Coarse-grained models of soft matter are usually combined with implicit solvent models that take the electrostatic polarizability into account via a dielectric background. In biophysical or nanoscale simulations that include water, this constant can vary greatly within the system. Performing molecular dynamics or other simulations that need to compute exact electrostatic interactions between charges in those systems is computationally demanding. We review here several algorithms developed by us that perform exactly this task. For planar dielectric surfaces in partial periodic boundary conditions, the arising image charges can be either treated with the MMM2D algorithm in a very efficient and accurate way or with the electrostatic layer correction term, which enables the user to use his favorite 3D periodic Coulomb solver. Arbitrarily-shaped interfaces can be dealt with using induced surface charges with the induced charge calculation (ICC* algorithm. Finally, the local electrostatics algorithm, MEMD(Maxwell Equations Molecular Dynamics, even allows one to employ a smoothly varying dielectric constant in the systems. We introduce the concepts of these three algorithms and an extension for the inclusion of boundaries that are to be held fixed at a constant potential (metal conditions. For each method, we present a showcase application to highlight the importance of dielectric interfaces.
Sumy, Danielle F.; Cochran, Elizabeth S.; Keranen, Katie M.; Wei, Maya; Abers, Geoffrey A.
2014-01-01
In November 2011, a M5.0 earthquake occurred less than a day before a M5.7 earthquake near Prague, Oklahoma, which may have promoted failure of the mainshock and thousands of aftershocks along the Wilzetta fault, including a M5.0 aftershock. The M5.0 foreshock occurred in close proximity to active fluid injection wells; fluid injection can cause a buildup of pore fluid pressure, decrease the fault strength, and may induce earthquakes. Keranen et al. [2013] links the M5.0 foreshock with fluid injection, but the relationship between the foreshock and successive events has not been investigated. Here we examine the role of coseismic Coulomb stress transfer on earthquakes that follow the M5.0 foreshock, including the M5.7 mainshock. We resolve the static Coulomb stress change onto the focal mechanism nodal plane that is most consistent with the rupture geometry of the three M ≥ 5.0 earthquakes, as well as specified receiver fault planes that reflect the regional stress orientation. We find that Coulomb stress is increased, e.g., fault failure is promoted, on the nodal planes of ~60% of the events that have focal mechanism solutions, and more specifically, that the M5.0 foreshock promoted failure on the rupture plane of the M5.7 mainshock. We test our results over a range of effective coefficient of friction values. Hence, we argue that the M5.0 foreshock, induced by fluid injection, potentially triggered a cascading failure of earthquakes along the complex Wilzetta fault system.
Perturbation Calculation of two-electron interaction in the ground of ...
African Journals Online (AJOL)
The single-band Hubbard model was studied in one dimensional lattice system which consist only of two sites. The perturbation calculation accounts for the ground state energy and its wave functions .The exact and perturbation calculation are in agreement when the value of the on-site coulomb interaction U is equal to ...
Current correlators in the Coulomb branch of N=4 SYM
Brandhuber, A; Brandhuber, Andreas; Sfetsos, Konstadinos
2000-01-01
We study correlators of R-symmetry currents in the Coulomb branch of N = 4 supersymmetric gauge theory in the large-N limit, using the AdS/CFT correspondence. In particular, we consider gauge fields in the presence of gravity and scalar fields parameterizing the coset SL(6,R)/SO(6) in the context of five-dimensional gauged supergravity. From a ten-dimensional point of view these backgrounds correspond to continuous D3-brane distributions. We find the surprising result that all 2-point functions of gauge currents fall into the same universality class, irrespectively of whether they correspond to broken or unbroken symmetries. We show that the problem of finding the spectrum can be mapped into an equivalent Schroedinger problem for supersymmetric quantum mechanics. The corresponding potential is the supersymmetric partner of the potential arising in studies of the spectrum for massless scalars and transverse graviton fluctuations in these backgrounds and the associated spectra are also identical. We discuss in ...
Coulomb nuclear interference with deuterons in even palladium isotopes
Energy Technology Data Exchange (ETDEWEB)
Rodrigues, M.R.D.; Rodrigues, C.L.; Borello-Lewin, T.; Horodynski-Matsushigue, L.B.; Duarte, J. L.M. [Sao Paulo Univ., SP (Brazil); Ukita, G.M. [Universidade de Santo Amaro, SP (Brazil). Faculdade de Psicologia
2004-09-15
Angular distributions for the inelastic scattering of 13.0 MeV deuterons on {sup 104,106,108,110}Pd were measured with the Sao Paulo Pelletron-Enge-Spectrograph facility in the range of 12{sup 0} {<=}{theta}{sub lab} {<=}64{sup 0}. A Coulomb-Nuclear Interference analysis, employing the Distorted Wave Born Approximation with the Deformed Optical Model as transition potential, under well established global optical parameters, was applied to the first quadrupolar excitations. The values of C = {delta}{sub LC}/{delta}{sub LN}, the ratio of charge to isoscalar deformation lengths, and of ({delta}{sub LN}){sup 2} were extracted through the comparison of experimental and predicted cross section angular distributions. The ratios of reduced charge to isoscalar transition probabilities, B(EL) to B(ISL) respectively, are related to the square of the parameter C and were thus obtained with the advantage of scale uncertainties cancellation. For {sup 104}Pd, and preliminary for {sup 108}Pd, the respective values of C = 1.18(3) and C = 1.13(4) reveal an enhanced contribution of the protons relative to the neutrons to the excitation, while a smaller effect is found for {sup 106}Pd, C = 1.06(3) and for {sup 110}Pd, C 1.07(3), in comparison with the value C 1.00 expected for homogenous collective excitations. (author)
Shape determination in Coulomb excitation of $^{72}$Kr
Reiter, P; Kruecken, R; Paul, E S; Wadsworth, R; Heenen, P
Nuclei with oblate shapes at low spins are very special in nature because of their rarity. Both theoretical and experimental shape co-existence studies in the mass 70 region for near proton drip-line nuclei suggest $^{72}$Kr to be the unique case with oblate low-lying and prolate high-lying levels. However, there is no direct experimental evidence in the literature to date for the oblate nature predicted for the first 2$^+$ state in $^{72}$Kr. We propose to determine the sign of the spectroscopic quadrupole moment of this state via the re-orientation effect in a low-energy Coulomb excitation measurement. In the inelastic excitation of the 2$^+$ state in $^{72}$Kr beam of 3.1 MeV/u with an intensity of 800 pps at REX-ISOLDE impinging on $^{104}$Pd target, the re-orientation effect plays a significant role. The cross section measurement for the 2$^+$ state should thus allow the model-independent determination of the sign of the quadrupole moment unambiguously and will shed light on the co-existing prolate and o...
Resonant Auger decay driving intermolecular Coulombic decay in molecular dimers.
Trinter, F; Schöffler, M S; Kim, H-K; Sturm, F P; Cole, K; Neumann, N; Vredenborg, A; Williams, J; Bocharova, I; Guillemin, R; Simon, M; Belkacem, A; Landers, A L; Weber, Th; Schmidt-Böcking, H; Dörner, R; Jahnke, T
2014-01-30
In 1997, it was predicted that an electronically excited atom or molecule placed in a loosely bound chemical system (such as a hydrogen-bonded or van-der-Waals-bonded cluster) could efficiently decay by transferring its excess energy to a neighbouring species that would then emit a low-energy electron. This intermolecular Coulombic decay (ICD) process has since been shown to be a common phenomenon, raising questions about its role in DNA damage induced by ionizing radiation, in which low-energy electrons are known to play an important part. It was recently suggested that ICD can be triggered efficiently and site-selectively by resonantly core-exciting a target atom, which then transforms through Auger decay into an ionic species with sufficiently high excitation energy to permit ICD to occur. Here we show experimentally that resonant Auger decay can indeed trigger ICD in dimers of both molecular nitrogen and carbon monoxide. By using ion and electron momentum spectroscopy to measure simultaneously the charged species created in the resonant-Auger-driven ICD cascade, we find that ICD occurs in less time than the 20 femtoseconds it would take for individual molecules to undergo dissociation. Our experimental confirmation of this process and its efficiency may trigger renewed efforts to develop resonant X-ray excitation schemes for more localized and targeted cancer radiation therapy.
Precise Lifetime Measurements in ^98Ru using Inverse Coulomb Excitation
Radeck, D.; Werner, V.; Ilie, G.; Ahn, T.; Casperson, R.; Heinz, A.; Wiliiams, E.; Smith, M.; Bettermann, L.; Chevrier, R.; McCarthy, D.; Anagnostatou, V.
2010-11-01
The mass region A 90-100 is of great interest in the study of the evolution of proton-neutron collectivity from spherical to deformed nuclei. Controversial publications concerning the vibrational character of 98Ru can be found in literature [1.2]. To get a comprehensive understanding of the structure, absolute transition strengths are important. With large uncertainties in essential quantities like the B4/2 value, theoretical interpretations remain difficult. In order to reduce uncertainties, the RDDS method using inverse Coulomb excitation was used to measure lifetimes. This technique, combined with the selective reaction, yields high precision lifetimes but several corrections are required due to relativistic and deorientation effects. Analysis techniques and results will be presented. New results on the absolute transition strengths are compared to known data on other nuclei in the mass region. [1] B. Cakirli et al., PRC 70, 044312 (2004). [2] E. Williams et al., PRC 74, 024302 (2006). This work was supported by the US DOE grant no. DE-FG02-91ER-40609 and D.R. thanks for financial support by the German Academic Exchange Service (DAAD).
Shape coexistence in neutron-rich Sr isotopes : Coulomb excitation of $^{96}$Sr
Clement, E; Siem, S; Czosnyka, T
2007-01-01
The nuclei in the mass region A $\\cong$ 100 around Sr and Zr show a dramatic change of the nuclear ground-state shape from near spherical for N $\\leq$ 58 to strongly deformed for N $\\geq$ 60. Theoretical calculations predict the coexistence of slightly oblate and strongly prolate deformed configurations in the transitional region. However, excited rotational structures based on the highly deformed configuration, which becomes the ground state at N = 60, are not firmly established in the lighter isotopes, and the earlier interpretation of a very abrupt change of shape has been challenged by recent experimental results in favor of a rather gradual change. We propose to study the electromagnetic properties of the neutron-rich nucleus $_{38}^{96}$Sr$_{58}$ by low-energy Coulomb excitation using the REX-ISOLDE facility and the MINIBALL detector array. Both transitional and diagonal matrix elements will be extracted, resulting in a complete description of the transition strengths and quadrupole moments of the low-l...
SRD 166 MEMS Calculator (Web, free access) This MEMS Calculator determines the following thin film properties from data taken with an optical interferometer or comparable instrument: a) residual strain from fixed-fixed beams, b) strain gradient from cantilevers, c) step heights or thicknesses from step-height test structures, and d) in-plane lengths or deflections. Then, residual stress and stress gradient calculations can be made after an optical vibrometer or comparable instrument is used to obtain Young's modulus from resonating cantilevers or fixed-fixed beams. In addition, wafer bond strength is determined from micro-chevron test structures using a material test machine.
Energy Technology Data Exchange (ETDEWEB)
García-Ravelo, J., E-mail: g.ravelo@hotmail.com [Departamento de Física, Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Edificio 9, Unidad Profesional Adolfo López Mateos, México D.F., 07738 (Mexico); Menéndez, A.; García-Martínez, J. [Departamento de Física, Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Edificio 9, Unidad Profesional Adolfo López Mateos, México D.F., 07738 (Mexico); Schulze-Halberg, A. [Department of Mathematics and Actuarial Science and Department of Physics, Indiana University Northwest, 3400 Broadway, Gary, IN 46408 (United States)
2014-06-13
We show that the effective Kratzer and Coulomb potentials can be obtained by taking particular limits of a multiparameter exponential potential that was studied recently. Moreover, we demonstrate that the bound state solutions of the exponential potential reduce correctly to their well-known counterparts associated with the Kratzer and Coulomb potentials. As a byproduct, we obtain a new limit relation for the hypergeometric function. - Highlights: • Kratzer and Coulomb potentials are limit cases of an exponential-type potential. • From exact s-waves, approximate solutions for l-waves are obtained. • l-waves of the potential tend to the solutions of the Kratzer and Coulomb potentials. • A non-evident identity between hypergeometric functions is demonstrated.
Light bending by a Coulomb field and the Aichelburg-Sexl ultraboost
Energy Technology Data Exchange (ETDEWEB)
Kozyulin, M V; Silagadze, Z K, E-mail: silagadze@inp.nsk.su [Novosibirsk State University, 630 090, Novosibirsk (Russian Federation)
2011-09-15
We use light deflection by a Coulomb field, due to nonlinear quantum electrodynamics effects, as an opportunity for a pedagogical discussion of the electrodynamical analogue of the Aichelburg-Sexl ultraboost.
Coulomb dissociation of {sup 8}B at 254 A MeV
Energy Technology Data Exchange (ETDEWEB)
Suemmerer, K.; Boue, F.; Baumann, T.; Geissel, H.; Hellstroem, M.; Koczon, P.; Schwab, E.; Schwab, W.; Senger, P.; Surowiecz, A. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany); Iwasa, N.; Ozawa, A. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany)]|[RIKEN Institute of Physical and Chemical Research, Saitama (Japan); Surowka, G. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany)]|[Jagiellonian Univ., Krakow (Poland). Inst. of Physics; Blank, B.; Czajkowski, S.; Marchand, C.; Pravikoff, M.S. [Centre d`Etudes Nucleaires de Bordeaux-Gradignan, 33 (France); Foerster, A.; Lauer, F.; Oeschler, H.; Speer, J.; Sturm, C.; Uhlig, F.; Wagner, A. [Technische Univ. Darmstadt (Germany); Gai, M. [Connecticut Univ., Storrs, CT (United States). Dept. of Physics; Grosse, E. [Inst. fuer Kern- und Hadronenphysik, Forschungszentrum Rossendorf, Dresden (Germany); Kohlmeyer, B. [Philipps Univ., Marburg (Germany). Fachbereich Physik; Kulessa, R.; Walus, W. [Jagiellonian Univ., Krakow (Poland). Inst. of Physics; Motobayashi, T. [Rikkyo Univ., Tokyo (Japan). Dept. of Physics; Teranishi, T. [RIKEN Institute of Physical and Chemical Research, Saitama (Japan)
1998-06-01
As an alternative method for determining the astrophysical S-factor for the {sup 7}Be(p,{gamma}){sup 8}B reaction we have measured the Coulomb dissociation of {sup 8}B at 254 A MeV. From our preliminary results, we obtain good agreement with both the accepted direct-reaction measurements and the low-energy Coulomb dissociation study of Iwasa et al. performed at about 50 A MeV. (orig.)
Coulomb gauge studies of SU(3) Yang-Mills theory on the lattice
Voigt, Aiko; Müller-Preussker, Michael; Sternbeck, Andre
2007-01-01
We study the infrared behaviour of lattice SU(3) Yang-Mills theory in Coulomb gauge in terms of the ghost propagator, the Coulomb potential and the transversal and the time-time component of the equal-time gluon propagator. In particular, we focus on the Gribov problem and its impact on the observables. We observe that the simulated annealing method is advantageous for fixing the Coulomb gauge in large volumes. We study finite size and discretization effects. While finite size effects can be controlled by the cone cut, and the ghost propagator and the Coulomb potential become scaling functions with the cylinder cut, the equal-time gluon propagator does not show scaling in the considered range of the inverse coupling constant. The ghost propagator is infrared enhanced. The Coulomb potential is now extended to considerably lower momenta and shows a more complicated infrared regime. The Coulomb string tension satisfies Zwanziger's inequality, but its estimate can be considered only preliminary because of the sys...
Variational calculation of the ground state of closed-shell nuclei up to A =40
Lonardoni, D.; Lovato, A.; Pieper, Steven C.; Wiringa, R. B.
2017-08-01
Variational calculations of ground-state properties of 4He,16O, and 40Ca are carried out employing realistic phenomenological two- and three-nucleon potentials. The trial wave function includes two- and three-body correlations acting on a product of single-particle determinants. Expectation values are evaluated with a cluster expansion for the spin-isospin dependent correlations considering up to five-body cluster terms. The optimal wave function is obtained by minimizing the energy expectation value over a set of up to 20 parameters by means of a nonlinear optimization library. We present results for the binding energy, charge radius, one- and two-body densities, single-nucleon momentum distribution, charge form factor, and Coulomb sum rule. We find that the employed three-nucleon interaction becomes repulsive for A ≥16 . In 16O the inclusion of such a force provides a better description of the properties of the nucleus. In 40Ca instead, the repulsive behavior of the three-body interaction fails to reproduce experimental data for the charge radius and the charge form factor. We find that the high-momentum region of the momentum distributions, determined by the short-range terms of nuclear correlations, exhibits a universal behavior independent of the particular nucleus. The comparison of the Coulomb sum rules for 4He,16O, and 40Ca reported in this work will help elucidate in-medium modifications of the nucleon form factors.
Woessner, J.
2012-07-14
Static stress transfer is one physical mechanism to explain triggered seismicity. Coseismic stress-change calculations strongly depend on the parameterization of the causative finite-fault source model. These models are uncertain due to uncertainties in input data, model assumptions, and modeling procedures. However, fault model uncertainties have usually been ignored in stress-triggering studies and have not been propagated to assess the reliability of Coulomb failure stress change (ΔCFS) calculations. We show how these uncertainties can be used to provide confidence intervals for co-seismic ΔCFS-values. We demonstrate this for the MW = 5.9 June 2000 Kleifarvatn earthquake in southwest Iceland and systematically map these uncertainties. A set of 2500 candidate source models from the full posterior fault-parameter distribution was used to compute 2500 ΔCFS maps. We assess the reliability of the ΔCFS-values from the coefficient of variation (CV) and deem ΔCFS-values to be reliable where they are at least twice as large as the standard deviation (CV ≤ 0.5). Unreliable ΔCFS-values are found near the causative fault and between lobes of positive and negative stress change, where a small change in fault strike causes ΔCFS-values to change sign. The most reliable ΔCFS-values are found away from the source fault in the middle of positive and negative ΔCFS-lobes, a likely general pattern. Using the reliability criterion, our results support the static stress-triggering hypothesis. Nevertheless, our analysis also suggests that results from previous stress-triggering studies not considering source model uncertainties may have lead to a biased interpretation of the importance of static stress-triggering.
Dynamic stresses, coulomb failure, and remote triggering: corrected
Hill, David P.
2012-01-01
Dynamic stresses associated with crustal surface waves with 15–30 s periods and peak amplitudes frictional strength threshold offer one explanation for instances of rapid‐onset triggered seismicity that develop during the surface‐wave peak dynamic stressing. Evaluation of the triggering potential of surface‐wave dynamic stresses acting on critically stressed faults using a Mohr’s circle representation together with the Coulomb failure criteria indicates that Love waves should have a higher triggering potential than Rayleigh waves for most fault orientations and wave incidence angles. That (1) the onset of triggered seismicity often appears to begin during the Rayleigh wave rather than the earlier arriving Love wave, and (2) Love‐wave amplitudes typically exceed those for Rayleigh waves suggests that the explanation for rapid‐onset dynamic triggering may not reside solely with a simple static‐threshold friction mode. The results also indicate that normal faults should be more susceptible to dynamic triggering by 20‐s Rayleigh‐wave stresses than thrust faults in the shallow seismogenic crust (<10 km) while the advantage tips in favor of reverse faults greater depths. This transition depth scales with wavelength and coincides roughly with the transition from retrograde‐to‐prograde particle motion. Locally elevated pore pressures may have a role in the observed prevalence of dynamic triggering in extensional regimes and geothermal/volcanic systems. The result is consistent with the apparent elevated susceptibility of extensional or transtensional tectonic regimes to remote triggering by Rayleigh‐wave dynamic stresses than compressional or transpressional regimes.
Extremes of 2d Coulomb gas: universal intermediate deviation regime
Lacroix-A-Chez-Toine, Bertrand; Grabsch, Aurélien; Majumdar, Satya N.; Schehr, Grégory
2018-01-01
In this paper, we study the extreme statistics in the complex Ginibre ensemble of N × N random matrices with complex Gaussian entries, but with no other symmetries. All the N eigenvalues are complex random variables and their joint distribution can be interpreted as a 2d Coulomb gas with a logarithmic repulsion between any pair of particles and in presence of a confining harmonic potential v(r) \\propto r2 . We study the statistics of the eigenvalue with the largest modulus r\\max in the complex plane. The typical and large fluctuations of r\\max around its mean had been studied before, and they match smoothly to the right of the mean. However, it remained a puzzle to understand why the large and typical fluctuations to the left of the mean did not match. In this paper, we show that there is indeed an intermediate fluctuation regime that interpolates smoothly between the large and the typical fluctuations to the left of the mean. Moreover, we compute explicitly this ‘intermediate deviation function’ (IDF) and show that it is universal, i.e. independent of the confining potential v(r) as long as it is spherically symmetric and increases faster than \\ln r2 for large r with an unbounded support. If the confining potential v(r) has a finite support, i.e. becomes infinite beyond a finite radius, we show via explicit computation that the corresponding IDF is different. Interestingly, in the borderline case where the confining potential grows very slowly as v(r) ∼ \\ln r2 for r \\gg 1 with an unbounded support, the intermediate regime disappears and there is a smooth matching between the central part and the left large deviation regime.
Interatomic Coulombic Decay as a New Source of Low Energy Electrons in slow Ion-Dimer Collisions
Iskandar, W; Leredde, A; Flechard, X; Gervais, B; Guillous, S; Hennecart, D; Mery, A; Rangama, J; Zhou, C L; Shiromaru, H; Cassimi, A
2014-01-01
We provide the experimental evidence that the single electron capture process in slow collisions between O$^{3+}$ ions and neon dimer targets leads to an unexpected production of low-energy electrons. This production results from the interatomic Coulombic decay process, subsequent to inner shell single electron capture from one site of the neon dimer. Although pure one-electron capture from inner shell is expected to be negligible in the low collision energy regime investigated here, the electron production due to this process overtakes by one order of magnitude the emission of Auger electrons by the scattered projectiles after double-electron capture. This feature is specific to low charge states of the projectile: similar studies with Xe$^{20+}$ and Ar$^{9+}$ projectiles show no evidence of inner shell single-electron capture. The dependence of the process on the projectile charge state is interpreted using simple calculations based on the classical over the barrier model.
Directory of Open Access Journals (Sweden)
M. Soltanolkotabi
1998-04-01
Full Text Available Single-valence electron atoms are an important class of atoms. Their oscillator strengths are their important properties. Knowing the oscillator strengths one can easity calculate the transition probabilities of the spectral lines and hence the lifetimes of energy levels of most atoms. The oscillator strengths of the spectral lines of most atoms are not knoen with sufficient accuracy due to the experimental difficulties. The results of most measurements are subject to large inaccuracies due to uncertainties in vapor pressure data. A quick and simple theoretical method for calculation of atomic oscillator strength seems to be the Coulomb approximation of Bates and Damagaard. This method reveals some interesting properties that are generally confirmed by experimental results. In this paper, we have studied oscillator strengths and line strengths of the different allowed transitions in AgI and AuI using the Coulomb approximation. The log (λfg curves(λ, f and g are the wavelength of transition, oscillator strength and statistical weight of upper level, respectively versus the reciprocal of the principal quantum number of upper level, 1/n, show a linear behavior only for large values of the principal quantum number of lower level. The effect of change of total angular momentum,Δ J, in the curvature and slope of the plotted curves has been also investigated. The deviation of the curves from straight lines, which indicates failure of the Coulomb approximation is due to the exchange forces. In addition, the n3fg curves (n , the effective total quantum number of upper level have been plotted versus n for different allowed transitions in AgL and AuI. It has been found that f is proportional to 1/n and this proportionality is linear for large values of n . For some transitions, however, there is a significant deviation from the linear dependence for large values of n , which can be attributed to the signature of total angular momentum quantum
A tool for standardized collector performance calculations including PVT
DEFF Research Database (Denmark)
Perers, Bengt; Kovacs, Peter; Olsson, Marcus
2012-01-01
in Europe. The collector parameters used as input in the tool are compiled from tests according to EN12975, without any intermediate conversions. The main target group for this tool is test institutes and certification bodies that are intended to use it for conversion of collector model parameters (derived...
Directly calculating electrical conductivities of dense hydrogen from molecular dynamics
Ma, Qian; Kang, Dongdong; Dai, Jiayu
2017-10-01
The transport properties are important in warm and hot dense matter in which the Coulomb interaction is dominated in the scattering process. Density functional theory (DFT) is considered as an effective method to investigate the transport properties, but the dynamical collisions between particles are missed. Here we use an electron force field (eFF) method based molecular dynamics (MD) to include the electronic quantum effects to investigate the transport properties of warm dense hydrogen. The eFF method can be regarded as the development of wave packets molecular dynamics and it has been successfully used to describe the thermodynamics of hydrogen, Auger process in diamondoids, the equation of states for dense lithium. The most important point of eFF method is assuming that each electron is considered as a Gaussian wave packet controlled by position and size while ions are still charged points. The electrical conductivity is calculated via the correlation of electrical current. The results show that electronic quantum effects are important for the transport properties in warm dense hydrogen such as diffusion coefficient and electrical conductivity, which are much smaller than the results from DFT calculations.
Tricriticality for dimeric Coulomb molecular crystals in ground state
Travěnec, Igor; Šamaj, Ladislav
2017-12-01
We study the ground-state properties of a system of dimers. Each dimer consists in a pair of equivalent charges at a fixed distance, immersed in a neutralizing homogeneous background. All charges interact pairwisely by Coulomb potential. The dimer centers form a two-dimensional rectangular lattice with the aspect ratio α\\in [0, 1] and each dimer is allowed to rotate around its center. The previous numerical simulations, made for the more general Yukawa interaction, indicate that only two basic dimer configurations can appear: either all dimers are parallel or they have two different angle orientations within alternating (checkerboard) sublattices. As the dimer size increases, two second-order phase transitions, related to two kinds of the symmetry breaking in dimer’s orientations, were reported. In this paper, we use a recent analytic method based on an expansion of the interaction energy in Misra functions which converges quickly and provides an analytic derivation of the critical behaviour. Our main result is that there exists a specific aspect ratio of the rectangular lattice α^*=0.714 106 840 000 71\\ldots which divides the space of model’s phases onto two distinct regions. If the lattice aspect ratio α>α* , we recover both types of the second-order phase transitions and find that they are of mean-field type with the critical exponent β = 1/2 . If 0.711 535≤slantα<α* , the phase transition associated with the discontinuity of dimer’s angles on alternating sublattices becomes of first order. For α=α* , the first- and second-order phase transitions meet at the tricritical point, characterized by the different critical index β = 1/4 . Such phenomenon is known from literature about the Landau theory of one-component fields, but in our two-component version the scenario is more complicated: the component which is already in the symmetry-broken state at the tricritical point also interferes and exhibits unexpectedly the mean-field singular
1994-01-01
MathSoft Plus 5.0 is a calculation software package for electrical engineers and computer scientists who need advanced math functionality. It incorporates SmartMath, an expert system that determines a strategy for solving difficult mathematical problems. SmartMath was the result of the integration into Mathcad of CLIPS, a NASA-developed shell for creating expert systems. By using CLIPS, MathSoft, Inc. was able to save the time and money involved in writing the original program.
Energy Technology Data Exchange (ETDEWEB)
Escrig, D. [Instituto de Estructura de la Materia, CSIC, E-28006 Madrid (Spain); Sanchez-Benitez, A.M. [Departamento de Fisica Aplicada, Universidad de Huelva, E-21071 Huelva (Spain); Institut de Physique Nucleaire and Centre de Recherches du Cyclotron, Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Moro, A.M. [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, Apdo. 1065, E-41080 Sevilla (Spain)]. E-mail: moro@us.es (and others)
2007-08-01
New experimental data from the scattering of {sup 6}He + {sup 208}Pb at energies around and below the Coulomb barrier are presented. The yield of breakup products coming from projectile fragmentation is dominated by a strong group of {alpha} particles. The energy and angular distribution of this group have been analyzed and compared with theoretical calculations. This analysis indicates that the {alpha} particles emitted at backward angles in this reaction are mainly due to two-neutron transfer to weakly bound states of the final nucleus.
Directory of Open Access Journals (Sweden)
Andrés Nieto Leal
2009-07-01
Full Text Available Este artículo presenta un programa de investigación desarrollado para la evaluación y determinación de los parámetros para los modelos constitutivos Mohr-Coulomb y Hardening Soil en suelos arcillosos. La metodología incluye el análisis de algunas correlaciones, ensayos básicos de caracterización y pruebas de compresión triaxial no drenada sobre muestras de suelo reconstituidas en laboratorio. A partir de los parámetros obtenidos se simuló el comportamiento esfuerzo-deformación en el programa de elementos finitos PLAXIS, evaluando a partir de un análisis comparativo, el desempeño de los modelos en relación con el comportamiento experimental del suelo. Del análisis realizado se aprecia que para el conjunto de parámetros considerados, los resultados computacionales muestran una correspondencia razonable y satisfactoria con los resultados experimentales, donde se observa una mejor aproximación al comportamiento descrito por las pruebas, en las simulaciones realizadas con el modelo Hardening Soil, cuyos resultados evidencian un mayor ajuste a la relación hiperbólica creciente, típica del tipo de suelo ensayado. De igual forma, los resultados obtenidos constituyen una validación importante de la metodología desarrollada.This article presents a research program developed for the evaluation and determination of the Morh-Coulomb model parameters and the Hardening Soil model parameters in clay soils. The metodology includes the analysis of some correlations, basic characterization soil tests and undrained compression triaxial tests carried out on reconstituted soil samples in laboratory (kaolin. From the obtained parameters the behavior stress-strain was simulated in the element finite software PLAXIS, examiningthe performance of the models by comparing the numeric calculation results with the experimental soil behavior. For the sets of considered model parameters, the analysis shows that the computational results have a reasonable
DEFF Research Database (Denmark)
Jensen, Bjarne Christian; Hansen, Svend Ole
Textbook on design of large panel building including rules on robustness and a method for producing the Statical documentattion......Textbook on design of large panel building including rules on robustness and a method for producing the Statical documentattion...
Coulomb spin liquid in anion-disordered pyrochlore Tb2Hf2O7.
Sibille, Romain; Lhotel, Elsa; Ciomaga Hatnean, Monica; Nilsen, Gøran J; Ehlers, Georg; Cervellino, Antonio; Ressouche, Eric; Frontzek, Matthias; Zaharko, Oksana; Pomjakushin, Vladimir; Stuhr, Uwe; Walker, Helen C; Adroja, Devashibhai T; Luetkens, Hubertus; Baines, Chris; Amato, Alex; Balakrishnan, Geetha; Fennell, Tom; Kenzelmann, Michel
2017-10-12
The charge ordered structure of ions and vacancies characterizing rare-earth pyrochlore oxides serves as a model for the study of geometrically frustrated magnetism. The organization of magnetic ions into networks of corner-sharing tetrahedra gives rise to highly correlated magnetic phases with strong fluctuations, including spin liquids and spin ices. It is an open question how these ground states governed by local rules are affected by disorder. Here we demonstrate in the pyrochlore Tb2Hf2O7, that the vicinity of the disordering transition towards a defective fluorite structure translates into a tunable density of anion Frenkel disorder while cations remain ordered. Quenched random crystal fields and disordered exchange interactions can therefore be introduced into otherwise perfect pyrochlore lattices of magnetic ions. We show that disorder can play a crucial role in preventing long-range magnetic order at low temperatures, and instead induces a strongly fluctuating Coulomb spin liquid with defect-induced frozen magnetic degrees of freedom.Experimental studies of frustrated spin systems such as pyrochlore magnetic oxides test our understanding of quantum many-body physics. Here the authors show experimentally that Tb2Hf2O7 may be a model material for investigating how structural disorder can stabilize a quantum spin liquid phase.
Configuration space Faddeev calculations. Progress report, 1 November 1992--31 October 1993
Energy Technology Data Exchange (ETDEWEB)
Payne, G.L.; Klink, W.H.; Polyzou, W.N.
1994-01-01
The detailed study of few-body systems provides one of the most precise tools for studying the dynamics of nuclei and nucleons. This research program consists of a careful theoretical study of few-body systems and methods for modeling these systems. Brief summaries are given on several aspects of this program including the following: the use of configuration-space Faddeev equations to solve the proton-deuteron scattering problem with long-range Coulomb interactions; calculations of the triton binding energy; inclusion of dynamical vacuum structures in Hamiltonian light-front dynamics; constraints in Bethe-Salpeter models; signature of quantum chaos; applications of point form relativistic quantum mechanics collective nuclear models and the symplectic group Sp (6,R); and anharmonic oscillators and quantum mechanics systems in nonconstant magnetic fields.
Multiphase flow calculation software
Fincke, James R.
2003-04-15
Multiphase flow calculation software and computer-readable media carrying computer executable instructions for calculating liquid and gas phase mass flow rates of high void fraction multiphase flows. The multiphase flow calculation software employs various given, or experimentally determined, parameters in conjunction with a plurality of pressure differentials of a multiphase flow, preferably supplied by a differential pressure flowmeter or the like, to determine liquid and gas phase mass flow rates of the high void fraction multiphase flows. Embodiments of the multiphase flow calculation software are suitable for use in a variety of applications, including real-time management and control of an object system.
Waste Package Lifting Calculation
Energy Technology Data Exchange (ETDEWEB)
H. Marr
2000-05-11
The objective of this calculation is to evaluate the structural response of the waste package during the horizontal and vertical lifting operations in order to support the waste package lifting feature design. The scope of this calculation includes the evaluation of the 21 PWR UCF (pressurized water reactor uncanistered fuel) waste package, naval waste package, 5 DHLW/DOE SNF (defense high-level waste/Department of Energy spent nuclear fuel)--short waste package, and 44 BWR (boiling water reactor) UCF waste package. Procedure AP-3.12Q, Revision 0, ICN 0, calculations, is used to develop and document this calculation.
The three-point function in split dimensional regularization in the Coulomb gauge
Leibbrandt, G
1998-01-01
We use a gauge-invariant regularization procedure, called ``split dimensional regularization'', to evaluate the quark self-energy $\\Sigma (p)$ and quark-quark-gluon vertex function $\\Lambda_\\mu (p^\\prime,p)$ in the Coulomb gauge, $\\vec{\\bigtriangledown}\\cdot\\vec{A}^a = 0$. The technique of split dimensional regularization was designed to regulate Coulomb-gauge Feynman integrals in non-Abelian theories. The technique which is based on two complex regulating parameters, $\\omega$ and $\\sigma$, is shown to generate a well-defined set of Coulomb-gauge integrals. A major component of this project deals with the evaluation of four-propagator and five-propagator Coulomb integrals, some of which are nonlocal. It is further argued that the standard one-loop BRST identity relating $\\Sigma$ and $\\Lambda_\\mu$, should by rights be replaced by a more general BRST identity which contains two additional contributions from ghost vertex diagrams. Despite the appearance of nonlocal Coulomb integrals, both $\\Sigma$ and $\\Lambda_\\...
Interplay between short-range correlated disorder and Coulomb interaction in nodal-line semimetals
Wang, Yuxuan; Nandkishore, Rahul M.
2017-09-01
In nodal-line semimetals, Coulomb interactions and short-range correlated disorder are both marginal perturbations to the clean noninteracting Hamiltonian. We analyze their interplay using a weak-coupling renormalization group approach. In the clean case, the Coulomb interaction has been found to be marginally irrelevant, leading to Fermi liquid behavior. We extend the analysis to incorporate the effects of disorder. The nodal line structure gives rise to kinematical constraints similar to that for a two-dimensional Fermi surface, which plays a crucial role in the one-loop renormalization of the disorder couplings. For a twofold degenerate nodal loop (Weyl loop), we show that disorder flows to strong coupling along a unique fixed trajectory in the space of symmetry inequivalent disorder couplings. Along this fixed trajectory, all symmetry inequivalent disorder strengths become equal. For a fourfold degenerate nodal loop (Dirac loop), disorder also flows to strong coupling, however, the strengths of symmetry inequivalent disorder couplings remain different. We show that feedback from disorder reverses the sign of the beta function for the Coulomb interaction, causing the Coulomb interaction to flow to strong coupling as well. However, the Coulomb interaction flows to strong coupling asymptotically more slowly than disorder. Extrapolating our results to strong coupling, we conjecture that at low energies nodal line semimetals should be described by a noninteracting nonlinear sigma model. We discuss the relation of our results with possible many-body localization at zero temperatures in such materials.
Room temperature Coulomb blockade mediated field emission via self-assembled gold nanoparticles
Energy Technology Data Exchange (ETDEWEB)
Wang, Fei [College of Physics and Electronics, Central South University, Changsha, Hunan 410073 (China); College of Science, National University of Defense Technology, Changsha, Hunan 410073 (China); Fang, Jingyue, E-mail: fjynudt@aliyun.com [College of Science, National University of Defense Technology, Changsha, Hunan 410073 (China); Chang, Shengli; Qin, Shiqiao; Zhang, Xueao [College of Science, National University of Defense Technology, Changsha, Hunan 410073 (China); Xu, Hui, E-mail: cmpxhg@csu.edu.cn [College of Physics and Electronics, Central South University, Changsha, Hunan 410073 (China)
2017-02-05
Coulomb blockade mediated field-emission current was observed in single-electron tunneling devices based on self-assembled gold nanoparticles at 300 K. According to Raichev's theoretical model, by fixing a proper geometric distribution of source, island and drain, the transfer characteristics can be well explained through a combination of Coulomb blockade and field emission. Coulomb blockade and field emission alternately happen in our self-assembled devices. The Coulomb island size derived from the experimental data is in good agreement with the average size of the gold nanoparticles used in the device. The integrated tunneling can be adjusted via a gate electrode. - Highlights: • The phenomenon of single-electron field emission in a transistor setting using self-assembled gold nanoparticles was investigated. • The transfer characteristics can be well explained by the model that is a combination of Coulomb blockage and field emission. • This transport mechanism is novel and may be used in many applications in field emission devices.
150 Years of Coulomb Stress History Along the California-Nevada Border, USA.
Carena, S.; Verdecchia, A.
2014-12-01
The temporal and spatial correlation among earthquakes in diffuse plate boundary zones is not well understood yet. The region north of the Garlock fault between the Sierra Nevada and Death Valley is part of a diffuse plate boundary zone, which absorbs a significant fraction of the plate motion between Pacific and North America. This area has experienced at least eight Mw ≥ 6 earthquakes in historical times, beginning with the 1872 Mw 7.5 Owens Valley earthquake. Furthermore, since 1978 Long Valley caldera has been undergoing periods of unrest, with earthquake swarms and resurgence. Our goal is to determine whether the 1872 Owens Valley earthquake has influenced the seismicity and volcanic activity in the area. We model the evolution of coseismic, interseismic and postseismic Coulomb stress (ΔCFS) in the region due to both earthquakes and caldera activity in the last 150 years. Our results show that the 1872 Owens Valley earthquake strongly encourages faulting in northern Owens Valley. In addition, there is a correlation among smaller events, in the form of a west-to-east migration of earthquakes from Long Valley caldera toward the White Mountains immediately following the 1978 caldera inflation event. The last event in this sequence, the 1986 Mw 6.3 Chalfant Valley earthquake, controls the location of over 80% of its own aftershocks, which occur in areas of positive ΔCFS and reach Mw 5.7. We also calculate the cumulative ΔCFS on several major active faults in the region. Stresses up to 30 bars and 10 bars respectively have accumulated on the White Mountains (Central section) and Deep Springs faults, comparable to the expected stress drop in an average earthquake. Because no surface ruptures more recent than 1.8 ka have been identified on these faults [dePolo, 1989; Lee et al., 2001], we consider them as likely candidates for the next major earthquake in the region.
Alvarez-Gómez, José A.; García-Mayordomo, Julián
2017-04-01
We present an automated free software-based toolchain to obtain Coulomb Failure Stress change maps on fault planes of interest following the occurrence of a relevant earthquake. The system uses as input the focal mechanism data of the event occurred and an active fault database for the region. From the focal mechanism the orientations of the possible rupture planes, the location of the event and the size of the earthquake are obtained. From the size of the earthquake, the dimensions of the rupture plane are obtained by means of an algorithm based on empirical relations. Using the active fault database in the area, the stress-receiving planes are obtained and a verisimilitude index is assigned to the source plane from the two nodal planes of the focal mechanism. The obtained product is a series of layers in a format compatible with any type of GIS (or map completely edited in PDF format) showing the possible stress change maps on the different families of fault planes present in the epicentral zone. These type of products are presented generally in technical reports developed in the weeks following the occurrence of the event, or in scientific publications; however they have been proven useful for emergency management in the hours and days after a major event being these stress changes responsible of aftershocks, in addition to the mid-term earthquake forecasting. The automation of the calculation allows its incorporation within the products generated by the alert and surveillance agencies shortly after the earthquake occurred. It is now being implemented in the Spanish Geological Survey as one of the products that this agency would provides after the occurrence of relevant seismic series in Spain.
Ground-state configuration of neutron-rich 35Al via Coulomb breakup
Chakraborty, S.; Datta, Ushasi; Aumann, T.; Beceiro-Novo, S.; Boretzky, K.; Caesar, C.; Carlson, B. V.; Catford, W. N.; Chartier, M.; Cortina-Gil, D.; De Angelis, G.; Fernandez, P. Diaz; Emling, H.; Ershova, O.; Fraile, L. M.; Geissel, H.; Gonzalez-Diaz, D.; Johansson, H.; Jonson, B.; Kalantar-Nayestanaki, N.; Kröll, T.; Krücken, R.; Langer, C.; Le Bleis, T.; Leifels, Y.; Marganiec, J.; Münzenberg, G.; Najafi, M. A.; Nilsson, T.; Nociforo, C.; Panin, V.; Plag, R.; Rahaman, A.; Reifarth, R.; Ricciardi, M. V.; Rigollet, C.; Rossi, D.; Scheidenberger, C.; Scheit, H.; Simon, H.; Taylor, J. T.; Togano, Y.; Typel, S.; Utsuno, Y.; Wagner, A.; Wamers, F.; Weick, H.; Winfield, J. S.
2017-09-01
The ground-state configuration of 35Al has been studied via Coulomb dissociation (CD) using the LAND-FRS setup (GSI, Darmstadt) at a relativistic energy of ˜403 MeV/nucleon. The measured inclusive differential CD cross section for 35Al, integrated up to 5.0 MeV relative energy between the 34Al core and the neutron using a Pb target, is 78(13) mb. The exclusive measured CD cross section that populates various excited states of 34Al is 29(7) mb. The differential CD cross section of 35Al→34Al+n has been interpreted in the light of a direct breakup model, and it suggests that the possible ground-state spin and parity of 35Al could be, tentatively, 1 /2+ or 3 /2+ or 5 /2+ . The valence neutrons, in the ground state of 35Al, may occupy a combination of either l =3 ,0 or l =1 ,2 orbitals coupled with the 34Al core in the ground and isomeric state(s), respectively. This hints of a particle-hole configuration of the neutron across the magic shell gaps at N =20 ,28 which suggests narrowing the magic shell gap. If the 5 /2+ is the ground-state spin-parity of 35Al as suggested in the literature, then the major ground-state configuration of 35Al is a combination of 34Al(g.s.;4-) ⊗νp3/2 and 34Al(isomer;1+) ⊗νd3/2 states. The result from this experiment has been compared with that from a previous knockout measurement and a calculation using the SDPF-M interaction.
Dynamic Analyses Including Joints Of Truss Structures
Belvin, W. Keith
1991-01-01
Method for mathematically modeling joints to assess influences of joints on dynamic response of truss structures developed in study. Only structures with low-frequency oscillations considered; only Coulomb friction and viscous damping included in analysis. Focus of effort to obtain finite-element mathematical models of joints exhibiting load-vs.-deflection behavior similar to measured load-vs.-deflection behavior of real joints. Experiments performed to determine stiffness and damping nonlinearities typical of joint hardware. Algorithm for computing coefficients of analytical joint models based on test data developed to enable study of linear and nonlinear effects of joints on global structural response. Besides intended application to large space structures, applications in nonaerospace community include ground-based antennas and earthquake-resistant steel-framed buildings.
National Stormwater Calculator
EPA’s National Stormwater Calculator (SWC) is a desktop application that estimates the annual amount of rainwater and frequency of runoff from a specific site anywhere in the United States (including Puerto Rico).
McCarty, George
1982-01-01
How THIS BOOK DIFFERS This book is about the calculus. What distinguishes it, however, from other books is that it uses the pocket calculator to illustrate the theory. A computation that requires hours of labor when done by hand with tables is quite inappropriate as an example or exercise in a beginning calculus course. But that same computation can become a delicate illustration of the theory when the student does it in seconds on his calculator. t Furthermore, the student's own personal involvement and easy accomplishment give hi~ reassurance and en couragement. The machine is like a microscope, and its magnification is a hundred millionfold. We shall be interested in limits, and no stage of numerical approximation proves anything about the limit. However, the derivative of fex) = 67.SgX, for instance, acquires real meaning when a student first appreciates its values as numbers, as limits of 10 100 1000 t A quick example is 1.1 , 1.01 , 1.001 , •••• Another example is t = 0.1, 0.01, in the functio...
Bauman, R. P.; Ferland, G. J.; MacAdam, K. B.
2002-12-01
The primordial abundance of helium and its subsequent production in stars are primarily determined from recombination lines in HII Regions. Accuracies better than a percent must be obtained to make definitive tests in cosmology. We report the results of a recalculation of the helium recombination process. Our work builds on previous calculations by improving the physical treatment of radiative recombination and subsequent cascades by explicitly including fine structure in the helium transition rates and energies. Transitions which are the result of singlet-triplet mixing are included in this work for the first time. We base our transition rates and energies on the results of Drake which include magnetic and relativistic interactions. Previous methodologies were largely based on variational, hydrogenic or Coulomb approximation calculations that did not include these interactions, thus entailing an unknown degree of inaccuracy. Comparisons with previous calculations are presented along with an assessment of the remaining major uncertainties. This project is supported by the NSF and NASA through grants AST 0071180 and NAG5-8212. G.W.F Drake, Atomic, Molecular, & Optical Physics Handbook, AIP Press, Woodbury New York, 1996.
Coulomb excitation of neutron-deficient polonium isotopes studied at ISOLDE
Neven, Michiel
The polonium isotopes represent an interesting region of the nuclear chart having only two protons outside the Z = 82 closed shell. These isotopes have already been extensively studied theoretically and experimentally. The heavier isotopes (A > 200) seem to follow a "regular seniority-type regime" while for the lighter isotopes (A < 200) a more collective behavior is observed. Many questions remain regarding the transition between these two regimes and the configuration mixing between quantum states. Experiments in the lighter polonium isotopes point to the presence of shape coexistence, however the phenomenon is not fully understood. A Coulomb excitation study of the polonium isotopes whereby the dynamic properties are investigated can provide helpful insights in understanding the shape coexistence phenomena. In this thesis $^{202}$Po was studied via Coulomb excitation. The $^{202}$Po isotope was part of an experimental campaign in which the $^{196,198,200,206}$Po isotopes were studied as well via Coulomb...
Hamiltonian approach to QCD in Coulomb gauge: Gribov’s confinement scenario at work*
Directory of Open Access Journals (Sweden)
Reinhardt H.
2017-01-01
Full Text Available I will review essential features of the Hamiltonian approach to QCD in Coulomb gauge showing that Gribov's confinement scenario is realized in this gauge. For this purpose I will discuss in detail the emergence of the horizon condition and the Coulomb string tension. I will show that both are induced by center vortex gauge field configurations, which establish the connection between Gribov’s confinement scenario and the center vortex picture of confinement. I will then extend the Hamiltonian approach to QCD in Coulomb gauge to finite temperatures, first by the usual grand canonical ensemble and second by the compactification of a spatial dimension. I will present results for the pressure, energy density and interaction measure as well as for the Polyakov loop.
Optimal Tuning of Amplitude Proportional Coulomb Friction Damper for Maximum Cable Damping
DEFF Research Database (Denmark)
Weber, Felix; Høgsberg, Jan Becker; Krenk, Steen
2010-01-01
This paper investigates numerically the optimal tuning of Coulomb friction dampers on cables, where the optimality criterion is maximum additional damping in the first vibration mode. The expression for the optimal friction force level of Coulomb friction dampers follows from the linear viscous...... damper via harmonic averaging. It turns out that the friction force level has to be adjusted in proportion to cable amplitude at damper position which is realized by amplitude feedback in real time. The performance of this adaptive damper is assessed by simulated free decay curves from which the damping...... to higher modes evoked by the amplitude proportional Coulomb friction damper which clamps the cable at its upper and lower positions. The resulting nonsinusoidal cable motion clearly violates the assumption of pure harmonic motion and explains why such dampers have to be tuned differently from optimal...
Val'kov, V. V.; Zlotnikov, A. O.
2017-11-01
We investigate the effect of the intersite Coulomb interaction in a planar system with the triangular lattice on the structure of chiral order parameter Δ( p) in the phase of coexisting superconductivity and noncollinear 120° magnetic ordering. It has been established that the Coulomb correlations in this phase initiate the state where the quasi-momentum dependence Δ( p) can be presented as a superposition of the chiral invariants corresponding to the {d_{{x^2} - {y^2}}} + i{d_{xy}} and p x + ip y symmetry types. It is demonstrated that the inclusion of the Coulomb interaction shifts the Δ( p) nodal point positions and, thereby, changes the conditions for a quantum topological transition.
DEFF Research Database (Denmark)
Petersen, Kurt Erling
1986-01-01
Risk and reliability analysis is increasingly being used in evaluations of plant safety and plant reliability. The analysis can be performed either during the design process or during the operation time, with the purpose to improve the safety or the reliability. Due to plant complexity and safety...... and availability requirements, sophisticated tools, which are flexible and efficient, are needed. Such tools have been developed in the last 20 years and they have to be continuously refined to meet the growing requirements. Two different areas of application were analysed. In structural reliability probabilistic...... approaches have been introduced in some cases for the calculation of the reliability of structures or components. A new computer program has been developed based upon numerical integration in several variables. In systems reliability Monte Carlo simulation programs are used especially in analysis of very...
Shan, Bin; Xiong, Xiong; Zheng, Yong; Wei, Shengji; Wen, Yangmao; Jin, Bikai; Ge, Can
2011-10-01
A moderate and widely felt earthquake of Ms7.1 (Mw6.9) occurred on April 14, 2010 in Yushu district of Qinghai province (China) which destroyed a large number of buildings and killed more than two thousand people. The distribution of the aftershock sequence is sparse, but with relatively large magnitudes (Ms6.3 and Ms5.7 aftershocks were recorded), strong aftershocks are still highly potential to occur in the near future. Therefore, it is critical to delineate areas where potential aftershocks could occur. Based on static stress triggering theory, we calculated the coseismic stress changes induced by the mainshock in Yushu County and its surrounding regions by adopting elastic dislocation theory and a multilayered crustal model. According to the rate- and state-variable friction law, we calculated the expected seismicity rate and probability of occurrences of M ≥ 5.0 earthquake in the next ten years. It is observed that the Coulomb stress changes increase apparently on the segment of the Wudaoliang-Qumalai Fault, the Batang-Luoxu and Dangjiang-Longbao segments of the Ganzi-Yushu Fault and the whole Wulanwula Lake-Yushu Fault. Based on the theory of Coulomb stress triggering, the probability of earthquake occurrence on these faults would increase in the near future. Considering the historical seismicity, the strain accumulation and the Coulomb stress changes, the probability of M ≥ 5 earthquake and M ≥ 6 earthquake occurrence in the entire study area in the next 10 years are 79-87% and 26.7-33.6%, respectively. Actually, a moderate earthquake of Ms5.3 occurred to the northwest of the Nangqian County on June 26, 2011.
Observation of a structural transition for coulomb crystals in a linear Paul trap
DEFF Research Database (Denmark)
Kjærgaard, N.; Drewsen, M.
2003-01-01
A structural transition for laser cooled ion Coulomb crystals in a linear Paul trap just above the stability limit of parametrically resonant excitation of bulk plasma modes has been observed. In contrast to the usual spheroidal shell structures present below the stability limit, the ions arrange...... in a "string-of-disks" configuration. The spheroidal envelopes of the string-of-disks structures are in agreement with results from cold fluid theory usually valid for ion Coulomb crystals if the ion systems are assumed to be rotating collectively....
An Alternative Simple Solution of the Sextic Anharmonic Oscillator and Perturbed Coulomb Problems
Ikhdair, Sameer M.; Sever, Ramazan
Utilizing an appropriate ansatz to the wave function, we reproduce the exact bound-state solutions of the radial Schrödinger equation to various exactly solvable sextic anharmonic oscillator and confining perturbed Coulomb models in D-dimensions. We show that the perturbed Coulomb problem with eigenvalue E can be transformed to a sextic anharmonic oscillator problem with eigenvalue hat E. We also check the explicit relevance of these two related problems in higher-space dimensions. It is shown that exact solutions of these potentials exist when their coupling parameters with k = D +2ℓ appearing in the wave equation satisfy certain constraints.
A rate-dependent Hosford-Coulomb model for predicting ductile fracture at high strain rates
Directory of Open Access Journals (Sweden)
Marcadet Stephane J.
2015-01-01
Full Text Available The Hosford-Coulomb model incorporates the important effect of the Lode angle parameter in addition to the stress triaxiality to predict the initiation of ductile fracture. A strain-rate dependent extension of the Hosford-Coulomb model is presented to describe the results from low, intermediate and high strain rate fracture experiments on advanced high strength steels (DP590 and TRIP780. The model predictions agree well with the experimental observation of an increase in ductility as function of strain rate for stress states ranging from uniaxial to equi-biaxial tension.
Anomalous Coulomb drag between bilayer graphene and a GaAs electron gas
Simonet, Pauline; Hennel, Szymon; Overweg, Hiske; Steinacher, Richard; Eich, Marius; Pisoni, Riccardo; Lee, Yongjin; Märki, Peter; Ihn, Thomas; Ensslin, Klaus; Beck, Mattias; Faist, Jérôme
2017-10-01
We report on Coulomb drag experiments between a bilayer graphene flake and a GaAs two-dimensional electron gas, where the charge-carrier densities of both systems can be tuned independently. For both p- and n-type graphene charge carriers, we observe that the Coulomb drag unexpectedly changes direction when the temperature is lowered. We find this phenomenon to be dominant when the Fermi wave vector in graphene is larger than in GaAs. At temperatures above ≈ 70 {{K}}, the drag signal is consistent with momentum exchange. In all discussed regimes, the Onsager relation is respected.
Energy Technology Data Exchange (ETDEWEB)
Kolenda, Stefan; Wolf, Michael J.; Beckmann, Detlef [Institut fuer Nanotechnologie, KIT, 76021 Karlsruhe (Germany)
2013-07-01
In normalmetal/superconductor hybrid structures nonlocal conductance is determined by crossed Andreev reflection (CAR) and elastic cotunneling (EC). This was investigated recently both experimentally and theoretically. Dynamical Coulomb blockade of EC and CAR was predicted theoretically. Here we report on experimental investigations of these effects. We found signatures of dynamical Coulomb blockade in local and nonlocal conductance in the normal state. In the superconducting state, we find s-shaped nonlocal differential conductance curves as a function of bias applied on both contacts. These curves were observed for bias voltages both below and above the gap. We compare our results to theory.
Hamiltonian approach to QCD in Coulomb gauge at zero and finite temperature
Directory of Open Access Journals (Sweden)
Reinhardt H.
2017-01-01
Full Text Available I report on recent results obtained within the Hamiltonian approach to QCD in Coulomb gauge. By relating the Gribov confinement scenario to the center vortex picture of confinement it is shown that the Coulomb string tension is tied to the spatial string tension. For the quark sector a vacuum wave functional is used which results in variational equations which are free of ultraviolet divergences. The variational approach is extended to finite temperatures by compactifying a spatial dimension. For the chiral and deconfinement phase transition pseudo-critical temperatures of 170MeV and 198 MeV, respectively, are obtained.
Stochastic Coulomb interactions in space charge limited electron emission
Nijkerk, M.D.; Kruit, P.
2004-01-01
A Monte Carlo simulation tool, which was used to evaluate the influence of discrete space charge effects on self-consistent calculations of cathode-ray tube optics, was discussed. It was found that interactions in the space charge cloud affect the electron trajectories such that the velocity
Slope Safety Factor Calculations With Non-Linear Yield Criterion Using Finite Elements
DEFF Research Database (Denmark)
Clausen, Johan; Damkilde, Lars
2006-01-01
The factor of safety for a slope is calculated with the finite element method using a non-linear yield criterion of the Hoek-Brown type. The parameters of the Hoek-Brown criterion are found from triaxial test data. Parameters of the linear Mohr-Coulomb criterion are calibrated to the same triaxial...
Studies of the nucler equation of state using numerical calculations of nuclear drop collisions
Alonso, C. T.; Leblanc, J. M.; Wilson, J. R.
1982-01-01
A numerical calculation for the full thermal dynamics of colliding nuclei was developed. Preliminary results are reported for the thermal fluid dynamics in such processes as Coulomb scattering, fusion, fusion-fission, bulk oscillations, compression with heating, and collisions of heated nuclei.
Dirac-Fock atomic electronic structure calculations using different nuclear charge distributions
Visscher, L; Dyall, KG
1997-01-01
Numerical Hartree-Fock calculations based on the Dirac-Coulomb Hamiltonian for the first 109 elements of the periodic table are presented. The results give the total electronic energy, as a function of the nuclear model that is used, for four different models of the nuclear charge distribution. The
A priori calculations for the rotational stabilisation
Directory of Open Access Journals (Sweden)
Iwata Yoritaka
2013-12-01
Full Text Available The synthesis of chemical elements are mostly realised by low-energy heavy-ion reactions. Synthesis of exotic and heavy nuclei as well as that of superheavy nuclei is essential not only to find out the origin and the limit of the chemical elements but also to clarify the historical/chemical evolution of our universe. Despite the life time of exotic nuclei is not so long, those indispensable roles in chemical evolution has been pointed out. Here we are interested in examining the rotational stabilisation. In this paper a priori calculation (before microscopic density functional calculations is carried out for the rotational stabilisation effect in which the balance between the nuclear force, the Coulomb force and the centrifugal force is taken into account.
Veltman, M.J.G.
1963-01-01
The wave function for a vector boson in a Coulomb field is obtained in a high energy approximation. The Furry wave function for a lepton in a Coulomb field is reconsidered and extended by taking into account a term hitherto neglected. Both wave functions are then applied to the coherent production
^{11}Li Breakup on ^{208}Pb at Energies Around the Coulomb Barrier
DEFF Research Database (Denmark)
Fernández-García, J.P.; Cubero, M.; Rodríguez-Gallardo, M.
2013-01-01
The inclusive breakup for the 11Li+208Pb reaction at energies around the Coulomb barrier has been measured for the first time. A sizable yield of 9Li following the 11Li dissociation has been observed, even at energies well below the Coulomb barrier. Using the first-order semiclassical perturbatio...
B-13,B-14(n,gamma) via Coulomb Dissociation for Nucleosynthesis towards the r-Process
Altstadt, S. G.; Adachi, T.; Aksyutina, Y.; Alcantara, J.; Alvarez-Pol, H.; Ashwood, N.; Atar, L.; Aumann, T.; Avdeichikov, V.; Barr, M.; Beceiro, S.; Bemmerer, D.; Benlliure, J.; Bertulani, C. A.; Boretzky, K.; Borge, M. J. G.; Burgunder, G.; Caamano, M.; Caesar, C.; Casarejos, E.; Catford, W.; Cederkall, J.; Chakraborty, S.; Chartier, M.; Chulkov, L.; Cortina-Gil, D.; Pramanik, U. Datta; Fernandez, P. Diaz; Dillmann, I.; Elekes, Z.; Enders, J.; Ershova, O.; Estrade, A.; Farinon, F.; Fraile, L. M.; Freer, M.; Freudenberger, M.; Fynbo, H. O. U.; Galaviz, D.; Geissel, H.; Gernhaeuser, R.; Goebel, K.; Golubev, P.; Gonzalez Diaz, D.; Hagdahl, J.; Heftrich, T.; Heil, M.; Heine, M.; Heinz, A.; Henriques, A.; Holl, M.; Holt, J. D.; Ickert, G.; Ignatov, A.; Jakobsson, B.; Johansson, H. T.; Jonson, B.; Kalantar-Nayestanaki, N.; Kanungo, R.; Kelic-Heil, A.; Knoebel, R.; Kroell, T.; Kruecken, R.; Kurcewicz, J.; Kurz, N.; Labiche, M.; Langer, C.; Le Bleis, T.; Lemmon, R.; Lepyoshkina, O.; Machado, J.; Marganiec, J.; Maroussov, V.; Menendez, J.; Mostazo, M.; Movsesyan, A.; Najafi, M. A.; Nilsson, T.; Nociforo, C.; Panin, V.; Perea, A.; Pietri, S.; Plag, R.; Prochazka, A.; Rahaman, A.; Rastrepina, G.; Reifarth, R.; Ribeiro, G.; Ricciardi, M. V.; Rigollet, C.; Riisager, K.; Roeder, M.; Rossi, D.; Sanchez del Rio, J.; Savran, D.; Scheit, H.; Schwenk, A.; Simon, H.; Simonis, J.; Sonnabend, K.; Sorlin, O.; Stoica, V.; Streicher, B.; Taylor, J.; Tengblad, O.; Terashima, S.; Thies, R.; Togano, Y.; Uberseder, E.; Van de Walle, J.; Velho, P.; Volkov, V.; Wagner, A.; Wamers, F.; Weick, H.; Weigand, M.; Wheldon, C.; Wilson, G.; Wimmer, C.; Winfield, J. S.; Woods, P.; Yakorev, D.; Zhukov, M. V.; Zilges, A.; Zoric, M.; Zuber, K.
Radioactive beams of B-14,B-15 produced by fragmentation of a primary Ar-40 beam were directed onto a Pb target to investigate the neutron breakup within the Coulomb field. The experiment was performed at the LAND/(RB)-B-3 setup. Preliminary results for the Coulomb dissociation cross sections as
Coulomb correlation effects in YBaCuO system
Energy Technology Data Exchange (ETDEWEB)
Costa-Quintana, J.; Lopez-Aguilar, F.; Munoz, J.S.; Sanchez, A. (Dept. de Fisica, Grupo de Electromagnetismo, Univ. Autonoma de Barcelona (Spain)); Balle, S. (Dept. de Fisica, Univ. de les Illes Balears, Palma de Mallorca (Spain))
1989-12-01
In this work, we apply a mean field potential deduced from the multiband Hubbard hamiltonian in order to obtain the lower and upper strongly correlated bands. We have obtained the total and partial density of states for U{sub d} = 0 and U{sub d} = 4 eV. The results show that the density of states calculated with U{sub d} = 4 eV at E{sub F} is lesser than that obtained with U{sub d} = 0. A small peak above E{sub F} arising from the strong correlated bands appears in the dDOS calculated with U{sub d} = 4 eV and this is in agreement with the experimental data. (orig.).
Coulomb excitation of $^{116}$Te and $^{118}$Te: a study of collectivity above the Z = 50 shell gap
Cederkall, J A; Smith, J F; Voulot, D; Rahkila, P J; Darby, I G; Hadinia, B; Grahn, T; Paul, E S; Wadsworth, R; Bree, N C F; Baeck, T M; Julin, R J; Diriken, J V J; Jenkins, D G; Kroell, T; Leske, J; Huyse, M L
We propose to study the nature and collectivity of low-energy excitations in $^{116}$Te and $^{118}$Te. We aim to measure the transition probability of the 0$^{+}$ $\\rightarrow$ 2$^{+}$ transition by means of Coulomb excitation, employing REX-ISOLDE and MINIBALL. The proposed study probes the systematics of B(E2) values in light Te nuclei, which lie in a region of the nuclear chart where unusual phenomena and evolution of collectivity have been observed. The proposed study will shed light on the role of the residual proton-neutron interactions in the development of collectivity when approaching the N = Z line. This is a resubmission of the P-277 proposal. The suggestions of INTC have been taken into account and the data from the Yale $^{120}$Te study has been included.
Cocco, M.; Hainzl, S.; Catalli, F.; Enescu, B.; Lombardi, A. M.; Woessner, J.
2010-05-01
We use the Dieterich (1994) physics-based approach to simulate the spatiotemporal evolution of seismicity caused by stress changes applied to an infinite population of nucleating patches modeled through a rate- and state-dependent friction law. According to this model, seismicity rate changes depend on the amplitude of stress perturbation, the physical constitutive properties of faults (represented by the parameter Aσ), the stressing rate, and the background seismicity rate of the study area. In order to apply this model in a predictive manner, we need to understand the impact of physical model parameters and the correlations between them. First, we discuss different definitions of the reference seismicity rate and show their impact on the computed rate of earthquake production for the 1992 Landers earthquake sequence as a case study. Furthermore, we demonstrate that all model parameters are strongly correlated for physical and statistical reasons. We discuss this correlation, emphasizing that the estimations of the background seismicity rate, stressing rate, and Aσ are strongly correlated to reproduce the observed aftershock productivity. Our analytically derived relation demonstrates the impact of these model parameters on the Omori-like aftershock decay: the c value and the productivity of the Omori law, implying a p value smaller than or equal to 1. Finally, we discuss an optimal strategy to constrain model parameters for near-real-time forecasts.
Li, Bin; Sørensen, Mathilde Bøttger; Atakan, Kuvvet
2015-12-01
The Shanxi rift system is one of the most active intraplate tectonic zones in the North China Block, resulting in devastating seismicity. Since 1303, the rift has experienced fifteen Ms ≥ 6.5 earthquakes. Aiming at a better understanding of Coulomb stress evolution and its relationship with the seismicity in the rift system, we investigated the Coulomb stress changes due to coseismic slip and post-seismic relaxation processes following strong earthquakes as well as the interseismic tectonic loading since the 1303 Hongdong Ms = 8.0 earthquake. Our calculation applies a specified regional medium model, takes the gravity effect into account and uses the fault geometry of the next event as the receiver fault in a given calculation. Our results show that nine out of 12 Ms ≥ 6.5 earthquakes since the 1303 Hongdong earthquake and more than 82 per cent of small-medium instrumental events after the 1989 Datong-Yanggao Ms = 6.1 earthquake fall into the total stress increased areas. Our results also reveal the different roles of the coseismic, post-seismic and interseismic Coulomb stress changes in the earthquake triggering process in the Shanxi rift system. In a short period after a strong event, the stress field changes are dominated by coseismic Coulomb stress due to sudden slip of the ruptured fault, while in the long term, the stress field is mainly dominated by the accumulation of interseismic tectonic loading. Post-seismic stress changes play an important role by further modifying the distribution of stress and therefore cannot be ignored. Based on the current stress status in the Shanxi rift system, the Linfen basin, southern and northern Taiyuan basin, Xinding basin and the north part of the rift system are identified as the most likely locations of large events in the future. The results of this study can provide important clues for the further understanding of seismic hazard in the Shanxi rift system and thus help guiding earthquake risk mitigation efforts in
Shan, B.; Xiong, X.; Zheng, Y.; Jin, B.
2011-12-01
A moderate and widely felt earthquake of Ms7.1 (Mw6.9) occurred on April 14, 2010 in Yushu district of Qinghai province (China) which destroyed a large number of buildings and killed more than two thousand people. The distribution of the aftershock sequence is sparse, but with relatively large magnitudes (Ms6.3 and Ms5.7 aftershocks were recorded), strong aftershocks are still highly potential to occur in the near future. Therefore, it is critical to delineate areas where potential aftershocks could occur. The slip model of Ms7.1 Yushu earthquake is derived by inverting the InSAR data. Based on static stress triggering theory, we calculated the coseismic stress changes induced by the mainshock in Yushu County and its surrounding regions by adopting elastic dislocation theory and a multilayered crustal model. According to the rate- and state-variable friction law, we calculated the expected seismicity rate and probability of occurrences of M≥5.0 earthquake in the next ten years. It is observed that the Coulomb stress changes increase apparently on the segment of the Wudaoliang-Qumalai Fault, the Batang-Luoxu and Dangjiang-Longbao segments of the Ganzi-Yushu Fault and the whole Wulanwula Lake-Yushu Fault. Based on the theory of Coulomb stress triggering, the probability of earthquake occurrence on these faults would increase in the near future. Considering the historical seismicity, the strain accumulation and the Coulomb stress changes, the expected seismicity in the region which located to the southwest of the rupture surface of Ms7.1 Yushu earthquake with increased Coulomb failure stress is stronger than the expected seismicity in region northeast to the rupture surface in the next 10 years. For the entire area, the probability of M≥5 earthquake and M≥6 earthquake occurrence in the next 10 years are 79~87% and 26.7~33.6%, respectively. Actually, a moderate earthquake of Ms5.3 occurred to the northwest of the Nangqian county on June 26, 2011.
Energy Technology Data Exchange (ETDEWEB)
Fujimoto, Kazuhiro J., E-mail: fujimoto@ruby.kobe-u.ac.jp [Department of Computational Science, Graduate School of System Informatics, Kobe University, 1-1, Rokkodai, Nada, Kobe 657-8501 (Japan)
2014-12-07
A transition charge, dipole, and quadrupole from electrostatic potential (TrESP-CDQ) method for electronic coupling calculations is proposed. The TrESP method is based on the classical description of electronic Coulomb interaction between transition densities for individual molecules. In the original TrESP method, only the transition charge interactions were considered as the electronic coupling. In the present study, the TrESP method is extended to include the contributions from the transition dipoles and quadrupoles as well as the transition charges. Hence, the self-consistent transition density is employed in the ESP fitting procedure. To check the accuracy of the present approach, several test calculations are performed to a helium dimer, a methane dimer, and an ethylene dimer. As a result, the TrESP-CDQ method gives a much improved description of the electronic coupling, compared with the original TrESP method. The calculated results also show that the self-consistent treatment to the transition densities contributes significantly to the accuracy of the electronic coupling calculations. Based on the successful description of the electronic coupling, the contributions to the electronic coupling are also analyzed. This analysis clearly shows a negligible contribution of the transition charge interaction to the electronic coupling. Hence, the distribution of the transition density is found to strongly influence the magnitudes of the transition charges, dipoles, and quadrupoles. The present approach is useful for analyzing and understanding the mechanism of excitation-energy transfer.
Calculation of photoionization differential cross sections using complex Gauss-type orbitals.
Matsuzaki, Rei; Yabushita, Satoshi
2017-09-05
Accurate theoretical calculation of photoelectron angular distributions for general molecules is becoming an important tool to image various chemical reactions in real time. We show in this article that not only photoionization total cross sections but also photoelectron angular distributions can be accurately calculated using complex Gauss-type orbital (cGTO) basis functions. Our method can be easily combined with existing quantum chemistry techniques including electron correlation effects, and applied to various molecules. The so-called two-potential formula is applied to represent the transition dipole moment from an initial bound state to a final continuum state in the molecular coordinate frame. The two required continuum functions, the zeroth-order final continuum state and the first-order wave function induced by the photon field, have been variationally obtained using the complex basis function method with a mixture of appropriate cGTOs and conventional real Gauss-type orbitals (GTOs) to represent the continuum orbitals as well as the remaining bound orbitals. The complex orbital exponents of the cGTOs are optimized by fitting to the outgoing Coulomb functions. The efficiency of the current method is demonstrated through the calculations of the asymmetry parameters and molecular-frame photoelectron angular distributions of H2+ and H2 . In the calculations of H2 , the static exchange and random phase approximations are employed, and the dependence of the results on the basis functions is discussed. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.
Richter, Martin; Schöffler, Markus; Jahnke, Till; Schmidt, Lothar Ph H; Dörner, Reinhard
2016-01-01
We report on electron momentum distributions from single ionization of Ar in strong orthogonally polarized two-color (OTC) laser fields measured with the COLTRIMS technique. We study the effect of Coulomb focusing whose signature is a cusp like feature in the center of the electron momentum spectrum. While the direct electrons show the expected strong dependence on the phase between the two colors, surprisingly the Coulomb focused structure is almost not influenced by the weak second harmonic streaking field. This effect is explained by the use of a CTMC simulation which describes the tunneled electron wave packet in terms of classical trajectories under the influence of the combined Coulomb- and OTC laser field. We find a subtle interplay between the initial momentum of the electron upon tunneling, the ionization phase and the action of the Coulomb field that makes the Coulomb focused part of the momentum spectrum apparently insensitive to the weaker streaking field.
Effective mass calculations for shallow acceptors in nitrides
Emmert-Aronson, Jacob; Lambrecht, W. R. L.
2012-02-01
In the effective mass approximation for shallow acceptors in semiconductors, the defect eigenstates are written as a product of a slowly varying envelope function and the band extrema Bloch functions. The Kohn-Luttinger Hamiltonian describing the valence band manifold in zincblende, or its generalization for other crystals structures, then becomes a set of coupled differential equations for the envelope function. These can be solved by a variational approach with hydrogenic type basis functions. We have implemented this approach for the appropriate Hamiltonians for zincblende, wurtzite and an orthorhombic crystal structure occurring for II-IV-N2 semiconductors. The Hamiltonian parameters used were extracted from first-principles GW calculations. The central cell correction to the Coulomb potential was added based on pseudopotential differences as proposed by Mireles and Ulloa (Phys. Rev. B 58, 3879 (1998)). Results are presented for various acceptors in GaN, AlN, InN, ZnGeN2 and ZnSnS2. The effects of varying the crystal field splitting parameter, and the type of pseudopotentials (including or not semicore d-states) were investigated.
The pushing gate in a planar Coulomb crystal using a flat-top laser beam
Energy Technology Data Exchange (ETDEWEB)
Kitaoka, M., E-mail: kitaoka@lyman.q.t.u-tokyo.ac.j [Department of Systems Innovation, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Buluta, I.M. [Department of Quantum Engineering and Systems Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Hasegawa, S., E-mail: hasegawa@sys.t.u-tokyo.ac.j [Department of Systems Innovation, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Department of Quantum Engineering and Systems Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)
2009-08-10
We propose a pushing gate for entangling two ions in a planar Coulomb crystal in the view of realizing large-scale quantum simulations. A tightly focused laser is irradiated from the direction perpendicular to the crystal plane and its spatial intensity profile generates a state-dependent force. We analyze the error sources in this scheme and obtain low infidelity.
The pushing gate in a planar Coulomb crystal using a flat-top laser beam
Kitaoka, M.; Buluta, I. M.; Hasegawa, S.
2009-08-01
We propose a pushing gate for entangling two ions in a planar Coulomb crystal in the view of realizing large-scale quantum simulations. A tightly focused laser is irradiated from the direction perpendicular to the crystal plane and its spatial intensity profile generates a state-dependent force. We analyze the error sources in this scheme and obtain low infidelity.
Jerky-type phenomena at nanocomposite surfaces : The breakdown of the coulomb friction law
Hosson, Jeff T.M. De; Pei, Yutao; Chen, Changqiang
This article concentrates on the jerky-type phenomenon of surfaces in relative motion (i.e., a breakdown of the Coulomb friction law) in nanocomposite materials. Physical arguments are provided to understand the dependence of friction on sliding velocity in the sense of self-lubrication. Also
On the integral representations of the Jost function and Coulomb off ...
Indian Academy of Sciences (India)
Abstract. The integral representations of the Jost function (on- and off-shell) are red- erived by the judicious use of the transposed operator relation on the particular integrals for Jost solution and using one of these particular integrals an analytical expression for the Coulomb off-shell Jost solution is presented in the maximal ...
Nonlocal Coulomb interaction in the two-dimensional spin-1/2 ...
Indian Academy of Sciences (India)
Abstract. The two-dimensional (2D) extended Falicov–Kimball model has been studied to ob- serve the role of nonlocal Coulomb interaction (Unc) using an exact diagonalization technique. The f-state occupation (n f ), the f–d intersite correlation function (cfd), the specific heat (C), entropy (S) and the specific heat coefficient ...
Equation satisfied by electron-electron mutual Coulomb repulsion energy density functional
Joubert, Daniel P.
2011-01-01
The electron-electron mutual Coulomb repulsion energy density functional satisfies an equation that links functionals and functional derivatives at N-electron and (N-1)-electron densities for densities determined from the same adiabatic scaled external potential for the N-electron system.
Ground-state configuration of neutron-rich Aluminum isotopes through Coulomb Breakup
Chakraborty, S.; Pramanik, U. Datta; Aumann, T.; Beceiro, S.; Boretzky, K.; Caesar, C.; Carlson, B.V.; Catford, W.N.; Chatterjee, S.; Chartier, M.; Cortina-Gil, D.; Angelis, G.De; Gonzalez - Dias, D.; Emling, H.; Diaz Fernandes, P.; Fraile, L.M.; Ershova, O.; Geissel, H.; Heil, M.; Jonson, B.; Kelic, A.; Johansson, H.; Kruecken, R.; Kroll, T.; Kurcewicz, J.; Langer, C.; Le Bleis, T.; Leifels, Y.; Munzenberg, G.; Marganiec, J.; Nociforo, C.; Najafi, A.; Panin, V.; Paschalis, S.; Pietri, S.; Plag, R.; Rahaman, A.; Reifarth, R.; Ricciardi, V.; Rossi, D.; Ray, J.; Simon, H.; Scheidenberger, C.; Typel, S.; Taylor, J.; Togano, Y.; Volkov, V.; Weick, H.; Wagner, A.; Wamers, F.; Weigand, M.; Winfield, J.S.; Yakorev, D.; Zoric, M.
2014-01-01
Neutron-rich 34,35Al isotopes have been studied through Coulomb excitation using LAND-FRS setup at GSI, Darmstadt. The method of invariant mass analysis has been used to reconstruct the excitation energy of the nucleus prior to decay. Comparison of experimental CD cross-section with direct breakup
Comment on an application of the asymptotic iteration method to a perturbed Coulomb model
Energy Technology Data Exchange (ETDEWEB)
Amore, Paolo [Facultad de Ciencias, Universidad de Colima, Bernal DIaz del Castillo 340, Colima (Mexico); Fernandez, Francisco M [INIFTA (Conicet, UNLP), Blvd. 113 y 64 S/N, Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina)
2006-08-18
We discuss a recent application of the asymptotic iteration method (AIM) to a perturbed Coulomb model. Contrary to what was argued before we show that the AIM converges and yields accurate energies for that model. We also consider alternative perturbation approaches and show that one of them is equivalent to that recently proposed by another author.
Non conventional screening of the Coulomb interaction in C-60 and in carbon nanotubes
van den Brink, J; Sawatzky, GA; Kuzmany, H; Fink, J; Mehring, M; Roth, S
1998-01-01
We study the screening of the Coulomb interaction in C-60 and carbon nanotubes. It is shown that for these systems the screening deviates strongly from the Clausius-Mossotti behavior. The short range interaction is strongly screened and the long range interaction is anti-screened, thereby strongly
COULOMB DISSOCIATION REACTION AND CORRELATIONS OF 2 HALO NEUTRONS IN LI-11
SHIMOURA, S; NAKAMURA, T; ISHIHARA, M; INABE, N; KOBAYASHI, T; KUBO, T; SIEMSSEN, RH; TANIHATA, [No Value; WATANABE, Y
1995-01-01
We have performed an exclusive measurement for the Coulomb dissociation reaction, Pb(Li-11,Li-9+2n)X at an incident energy of 43 A MeV. The deduced excitation energy spectrum of the Li-11 nucleus shows a prominent peak at 1 MeV with a large tail towards higher excitation energies. The relative
On-shell and half-shell effects of the coulomb potential in quantum mechanics
Maag, Jan Willem de
1984-01-01
In dit proefschrift wordt de Coulomb potentiaal in de nietrelativistische quantummechanica bestudeerd. Met gebruik van een streng wiskundige beschrijving onderzoeken we, in het bijzonder, on-shell en off-shell eigenschappen. De overeenkomsten en de verschillen met het geval van een glad afgeschermde
An Efficient Return Algorithm for Non-Associated Mohr-Coulomb Plasticity
DEFF Research Database (Denmark)
Clausen, Johan Christian; Damkilde, Lars; Andersen, Lars
2005-01-01
An efficient return algorithm for stress update in numerical plasticity computations is presented. The yield criterion must be linear in principal stress space, and can be composed of any number of yield planes. Each of these yield planes can have an associated or non-associated flow rule...... considerations. The method is exemplified on non-associated Mohr-Coulomb plasticity throughout the paper....
An efficient Return Algorithm for Non-Associated Mohr-Coulomb Plasticity
DEFF Research Database (Denmark)
Clausen, Johan; Damkilde, Lars; Andersen, Lars
2005-01-01
An efficient return algorithm for stress update in numerical plasticity computations is presented. The yield criterion must be linear in principal stress space, and can be composed of any number of yield planes. Each of these yield planes can have an associated or non-associated flow rule...... considerations. The method is exemplified on non-associated Mohr-Coulomb plasticity throughout the paper....
Dynamics of Braking Vehicles: From Coulomb Friction to Anti-Lock Braking Systems
Tavares, J. M.
2009-01-01
The dynamics of braking of wheeled vehicles is studied using the Coulomb approximation for the friction between road and wheels. The dependence of the stopping distance on the mass of the vehicle, on the number of its wheels and on the intensity of the braking torque is established. It is shown that there are two regimes of braking, with and…
Coulomb-Modified Fano Resonance in a One-Lead Quantum Dot
DEFF Research Database (Denmark)
Johnson, Anna Ansaba; M. Marcus, C.; Hanson, Mats
2003-01-01
We investigate a tunable Fano interferometer consisting of a quantum dot coupled via tunneling to a one-dimensional channel. In addition to Fano resonance, the channel shows strong Coulomb response to the dot, with a single electron modulating channel conductance by factors of up to 100. Where...
Nonlocal Coulomb interaction in the two-dimensional spin-1/2 ...
Indian Academy of Sciences (India)
Nonlocal Coulomb interaction-induced discontinuous insulator-to-metal transition occurs at a critical f-level energy. More ordered state is obtained with the increase of nc. In the speciﬁc heat curves, two-peak structure as well as a singlepeak structure appears. At low-temperature region, a sharp rise in the speciﬁc heat ...
Predicting transport regime and local electrostatic environment from Coulomb blockade diamond sizes
DEFF Research Database (Denmark)
Olsen, Stine Tetzschner; Hansen, Thorsten; Mikkelsen, Kurt Valentin
2017-01-01
Electron transport through a molecule is often described in one of the two regimes: the coherent tunnelling regime or the Coulomb blockade regime. The twilight zone of the two regimes still possesses many unsolved questions. A theoretical analysis of the oligophenylenevinylene OPV3 experiments by...
Dissociation of deuteron, 6He and 11Be from Coulomb dissociation ...
Indian Academy of Sciences (India)
The fragmentation of deuteron, 6He and 11Be have been studied during interaction with the 208Pb nucleus at various projectile energies. The Coulomb dissociation cross-sections and the momentum distribution of the break-up fragments have been analysed within the framework of the direct fragmentation model.
The problem of true macroscopic charge quantization in the Coulomb blockade
Burmistrov, I.S.; Pruisken, A.M.M.; Bonča, J.; Kruchinin, S.
2008-01-01
Based on the Ambegaokar-Eckern-Schön approach to the Coulomb blockade we develop a complete quantum theory of the single electron transistor. We identify a previously unrecognized physical observable in the problem that, unlike the usual average charge on the island, is robustly quantized for any
Bao, Junwei Lucas; Sripa, Pattrawan; Truhlar, Donald G
2016-01-14
Multi-path variational transition state theory (MP-VTST) provides a conformationally complete framework for calculating gas-phase rate constants. For reactions in which the transition state has distinguishable torsional minima (which include most reactions), there are multiple possible reaction paths. In principle MP-VTST includes the contributions from all the reaction paths, and it should explicitly treat the variational and tunneling effects of each path, but in practice one may need to truncate the number of paths included in MP-VTST calculations in order to achieve a balance between computational cost and accuracy. In this work, we present calculations including all paths for two prototype combustion reactions, namely the two hydrogen abstraction reactions from tert-butanol by HO2 radical. For both reactions we included all the reaction paths. Since abstraction at C has 46 paths, it provided a good opportunity to carry out a case study in which we investigated the errors introduced by truncating the number of paths. For the reaction studied, we found that the variational and multidimensional tunneling transmission coefficients are very different for different reaction paths, which provides new evidence that MP-VTST is necessary for treating path-dependent variational effects and multidimensional tunneling. We found that tunneling transmission coefficients can be much larger for higher-energy paths than for lower-energy ones. Interestingly, the simple hypothesis that higher barriers are narrower does not explain this finding in the present case; we found instead that the effect is due to higher-energy barriers having the possibility of tunneling at energies farther below the barrier top. We also show that a previously applied criterion for judging convergence with respect to the number of paths may not be reliable at low temperature.
Ideal Coulomb Plasma Approximation in Line Shape Models: Problematic Issues
Directory of Open Access Journals (Sweden)
Joel Rosato
2014-06-01
Full Text Available In weakly coupled plasmas, it is common to describe the microfield using a Debye model. We examine here an “artificial” ideal one-component plasma with an infinite Debye length, which has been used for the test of line shape codes. We show that the infinite Debye length assumption can lead to a misinterpretation of numerical simulations results, in particular regarding the convergence of calculations. Our discussion is done within an analytical collision operator model developed for hydrogen line shapes in near-impact regimes. When properly employed, this model can serve as a reference for testing the convergence of simulations.
Atomistic calculation of electronic and optical properties of a single InAs quantum dots
Zielinski, M.; Korkusinski, M.; Sheng, W.; Hawrylak, P.
2008-03-01
We present an atomistic tight-binding (TB) theory of electronic structure and optical properties of a single self-assembled InAs quantum dot (SAD). In previous work an effective-bond-orbital model (EBOM) was used to calculate electron and hole states of the SAD. The strain distribution was calculated using the continuum elasticity theory and EBOM was coupled to the strain via the Bir-Pikus Hamiltonian. However, the properties of these multimillion-atom systems are influenced by the presence of crystal facets and the symmetry of underlying zinc-blende lattice. In current work we present a fully atomistic TB model, accounting for the atomistic symmetry, and extended to include d-orbitals for proper treatment of interband/intervalley couplings. Strain is included in the Hamiltonian via Slater-Koster rules and a generalized Harrison law, with the equilibrium positions of atoms calculated using the valence force field method. Coulomb matrix elements are found using the TB functions, and electronic properties of N confined excitons (N=1-6) are determined in the CI approach. Emission spectra of multiexcitons are also obtained. Comparison with the previous approach and the experimental results is presented.
Dynamics of fission and Coulomb explosion of multicharged large finite systems
Levy, Y.; Last, I.; Jortner, J.
This paper reports on studies of the fragmentation dynamics of multicharged (A+)55 Morse clusters, where the variation of the range of the Morse potential parameters induces cluster fission for a long-range potential and Coulomb explosion for a short-range potential. The multidimensional energy landscapes for these fragmentation processes were explored by constructing reduced coordinates utilizing the principal component analysis (PCA), which was previously applied for the energy landscapes and folding dynamics of biomolecules. The distance-matrix based PCA was applied to study the effects of the potential on the fragmentation dynamics and to explore the structural diversity of the fragmentation processes. The first principal coordinate (which captures 95% of the dynamic information content for each trajectory) constitutes an appropriate reaction coordinate for both fission and Coulomb explosion and was used to determine the temperature-dependent fragmentation rates. These obey the Arrhenius law, with the barrier for fission (0.36 eV) being higher than for Coulomb explosion (0.22 eV). Structural and energetic information on the radius of gyration and on the potential energy for small values of the reaction coordinate manifest considerably larger fluctuations for fission than for Coulomb explosion, indicating that in the former case the cluster shrinks and swells prior to dissociation. The joint projection of multiple trajectories for each fragmentation process allows for the description of the energy landscapes and fragmentation pathways in terms of two principal coordinates, which manifest a form of 'ski slopes'. Different collective coordinates describe the spatially isotropic Coulomb explosion and the spatially unisotropic fission.
Levallois, J.; Tran, M. K.; Pouliot, D.; Presura, C. N.; Greene, L. H.; Eckstein, J. N.; Uccelli, J.; Giannini, E.; Gu, G. D.; Leggett, A. J.; van der Marel, D.
2016-07-01
We performed an experimental study of the temperature and doping dependence of the energy-loss function of the bilayer and trilayer bismuth cuprates family. The primary aim is to obtain information on the energy stored in the Coulomb interaction between the conduction electrons, on the temperature dependence thereof, and on the change of Coulomb interaction when Cooper pairs are formed. We performed temperature-dependent ellipsometry measurements on several Bi2 Sr2 CaCu2 O8 -x single crystals: underdoped with Tc=60 , 70, and 83 K; optimally doped with Tc=91 K ; overdoped with Tc=84 , 81, 70, and 58 K; as well as optimally doped Bi2 Sr2 Ca2 Cu3 O10 +x with Tc=110 K . Our first observation is that, as the temperature drops through Tc, the loss function in the range up to 2 eV displays a change of temperature dependence as compared to the temperature dependence in the normal state. This effect at—or close to—Tc depends strongly on doping, with a sign change for weak overdoping. The size of the observed change in Coulomb energy, using an extrapolation with reasonable assumptions about its q dependence, is about the same size as the condensation energy that has been measured in these compounds. Our results therefore lend support to the notion that the Coulomb energy is an important factor for stabilizing the superconducting phase. Because of the restriction to small momentum, our observations do not exclude a possible significant contribution to the condensation energy of the Coulomb energy associated with the region of q around (π ,π ).
Directory of Open Access Journals (Sweden)
J. Levallois
2016-08-01
Full Text Available We performed an experimental study of the temperature and doping dependence of the energy-loss function of the bilayer and trilayer bismuth cuprates family. The primary aim is to obtain information on the energy stored in the Coulomb interaction between the conduction electrons, on the temperature dependence thereof, and on the change of Coulomb interaction when Cooper pairs are formed. We performed temperature-dependent ellipsometry measurements on several Bi_{2}Sr_{2}CaCu_{2}O_{8-x} single crystals: underdoped with T_{c}=60, 70, and 83 K; optimally doped with T_{c}=91 K; overdoped with T_{c}=84, 81, 70, and 58 K; as well as optimally doped Bi_{2}Sr_{2}Ca_{2}Cu_{3}O_{10+x} with T_{c}=110 K. Our first observation is that, as the temperature drops through T_{c}, the loss function in the range up to 2 eV displays a change of temperature dependence as compared to the temperature dependence in the normal state. This effect at—or close to—T_{c} depends strongly on doping, with a sign change for weak overdoping. The size of the observed change in Coulomb energy, using an extrapolation with reasonable assumptions about its q dependence, is about the same size as the condensation energy that has been measured in these compounds. Our results therefore lend support to the notion that the Coulomb energy is an important factor for stabilizing the superconducting phase. Because of the restriction to small momentum, our observations do not exclude a possible significant contribution to the condensation energy of the Coulomb energy associated with the region of q around (π,π.
34 CFR 303.15 - Include; including.
2010-07-01
... 34 Education 2 2010-07-01 2010-07-01 false Include; including. 303.15 Section 303.15 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION EARLY INTERVENTION PROGRAM FOR INFANTS AND TODDLERS WITH...
Energy Technology Data Exchange (ETDEWEB)
Guichard, R
2007-12-15
We present a theoretical approach using Coulomb-Volkov states that appears useful for the study of atomic multi-photonic processes induced by intense XUV femtosecond laser pulses. It predicts hydrogen ionization spectra when it is irradiated by laser pulses in perturbations conditions. Three ways have been investigated. Extension to strong fields when {Dirac_h}{omega} > I{sub p}: it requires to include the hydrogen ground state population, introducing it in standard Coulomb-Volkov amplitude leads to saturated multi-photonic ionization. Extension to multi-photonic transitions with {Dirac_h}{omega} < I{sub p}: new quantum paths are open by the possibility to excite the lower hydrogen bound states. Multiphoton excitation of these states is investigated using a Coulomb-Volkov approach. Extension to helium: two-photon double ionization study shows the influence of electronic correlations in both ground and final state. Huge quantity of information such as angular and energetic distributions as well as total cross sections is available. (author)
Directory of Open Access Journals (Sweden)
M. Utkucu
2013-07-01
Full Text Available Coulomb stress changes before and after the 23 October 2011 Van, eastern Turkey, earthquake have been analysed using available data related to the background and the aftershock seismicity and the source faults. The coseismic stress changes of the background seismicity had slightly promoted stress over the rupture plane of the 2011 Van earthquake, while it yielded a stress shadow over the Gürpı nar Fault which has been argued to have produced the 7 April 1646 Van earthquake. The stress shadow over the Gürpi nar fault has become more pronounced following the occurrence of the 2011 Van earthquake, meaning that the repetition of the 1646 Van earthquake has been further suppressed. Spatial distribution and source mechanisms of the 2011 Van earthquake's aftershocks have been utilised to define four clusters with regard to their relative location to the mainshock rupture. In addition, the aftershock sequence covers a much broader area toward the northeast. Correlations between the observed spatial patterns of the aftershocks and the coseismic Coulomb stress changes caused by the mainshock are determined by calculating the stress changes over both optimally oriented and specified fault planes. It is shown here that there is an apparent correlation between the mainshock stress changes and the observed spatial pattern of the aftershock occurrence, demonstrating the usefulness of the stress maps in constraining the likely locations of the upcoming aftershocks and mitigating earthquake hazard.
Utkucu, M.; Durmuş, H.; Yalçın, H.; Budakoğlu, E.; Işık, E.
2013-07-01
Coulomb stress changes before and after the 23 October 2011 Van, eastern Turkey, earthquake have been analysed using available data related to the background and the aftershock seismicity and the source faults. The coseismic stress changes of the background seismicity had slightly promoted stress over the rupture plane of the 2011 Van earthquake, while it yielded a stress shadow over the Gürpı nar Fault which has been argued to have produced the 7 April 1646 Van earthquake. The stress shadow over the Gürpi nar fault has become more pronounced following the occurrence of the 2011 Van earthquake, meaning that the repetition of the 1646 Van earthquake has been further suppressed. Spatial distribution and source mechanisms of the 2011 Van earthquake's aftershocks have been utilised to define four clusters with regard to their relative location to the mainshock rupture. In addition, the aftershock sequence covers a much broader area toward the northeast. Correlations between the observed spatial patterns of the aftershocks and the coseismic Coulomb stress changes caused by the mainshock are determined by calculating the stress changes over both optimally oriented and specified fault planes. It is shown here that there is an apparent correlation between the mainshock stress changes and the observed spatial pattern of the aftershock occurrence, demonstrating the usefulness of the stress maps in constraining the likely locations of the upcoming aftershocks and mitigating earthquake hazard.
Numerical Exact Ab Initio Four-Nucleon Scattering Calculations: from Dream to Reality
Fonseca, A. C.; Deltuva, A.
2017-03-01
In the present manuscript we review the work of the last ten years on the pursuit to obtain numerical exact solutions of the four-nucleon scattering problem using the most advanced force models that fit two nucleon data up to pion production threshold with a χ ^2 per data point approximately one, together with the Coulomb interaction between protons; three- and four-nucleon forces are also included in the framework of a meson exchange potential model where NN couples to NΔ. Failure to describe the world data on four-nucleon scattering observables in the framework of a non relativistic scattering approach falls necessarily on the force models one uses. Four-nucleon observables pose very clear challenges, particular in the low energy region where there are a number of resonances whose position and width needs to be dynamically generated by the nucleon-nucleon (NN) interactions one uses. In addition, our calculations constitute the most advance piece of work where observables for all four-nucleon reactions involving isospin I=0, I=0 coupled to I=1 and isospin I=1 initial states are calculated at energies both below and above breakup threshold. We also present a very extensive comparison between calculated results and data for cross sections and spin observables. Therefore the present work reveals both the shortcomings and successes of some of the present NN force models in describing four-nucleon data and serve as a benchmark for future developments.
Chemical calculations and chemicals that might calculate
Barnett, Michael P.
I summarize some applications of symbolic calculation to the evaluation of molecular integrals over Slater orbitals, and discuss some spin-offs of this work that have wider potential. These include the exploration of the mechanized use of analogy. I explain the methods that I use to do this, in relation to mathematical proofs and to modeling step by step processes such as organic syntheses and NMR pulse sequences. Another spin-off relates to biological information processing. Some challenges and opportunities in the information infrastructure of interdisciplinary research are discussed.
Ren, Xueguang; Miteva, Tsveta; Kolorenč, Přemysl; Gokhberg, Kirill; Kuleff, Alexander I.; Cederbaum, Lorenz S.; Dorn, Alexander
2017-09-01
We investigate the interatomic Coulombic decay (ICD) in argon dimers induced by electron-impact ionization (E0=90 eV ) using a multiparticle coincidence experiment in which the momentum vectors and, consequently, the kinetic energies for electrons and fragment ions are determined. The signature of the ICD process is obtained from a correlation map between ejected electron energy and kinetic energy release (KER) for Ar++Ar+ fragment ions where low-energy ICD electrons can be identified. Furthermore, two types of ICD processes, termed fast and slow interatomic decay, are separated by the ICD initial-state energies and projectile energy losses. The dependence of the energies of emitted low-energy ICD electrons on the initial-state energy is studied. ICD electron energy spectra and KER spectra are obtained separately for fast and slow decay processes where the KER spectra for the slow decay channel are strongly influenced by nuclear motion. The KER and ICD electron energy spectra are well reproduced by ab initio calculations.
Dutta, Rishabh
2017-12-20
Several researchers have studied the source parameters of the 2005 Fukuoka (northwestern Kyushu Island, Japan) earthquake (MW 6.6) using teleseismic, strong motion and geodetic data. However, in all previous studies, errors of the estimated fault solutions have been neglected, making it impossible to assess the reliability of the reported solutions. We use Bayesian inference to estimate the location, geometry and slip parameters of the fault and their uncertainties using Interferometric Synthetic Aperture Radar (InSAR) and Global Positioning System (GPS) data. The offshore location of the earthquake makes the fault parameter estimation challenging, with geodetic data coverage mostly to the southeast of the earthquake. To constrain the fault parameters, we use a priori constraints on the magnitude of the earthquake and the location of the fault with respect to the aftershock distribution and find that the estimated fault slip ranges from 1.5 m to 2.5 m with decreasing probability. The marginal distributions of the source parameters show that the location of the western end of the fault is poorly constrained by the data whereas that of the eastern end, located closer to the shore, is better resolved. We propagate the uncertainties of the fault model and calculate the variability of Coulomb failure stress changes for the nearby Kego fault, located directly below Fukuoka city, showing that the mainshock increased stress on the fault and brought it closer to failure.
Rösch, Daniel; Willitsch, Stefan; Chang, Yuan-Pin; Küpper, Jochen
2014-03-01
Many molecules exhibit multiple conformers that often easily interconvert under thermal conditions. Therefore, single conformations are difficult to isolate which renders the study of their distinct chemical reactivities challenging. We have recently reported a new experimental method for the characterization of conformer-specific effects in chemical reactions [Y.-P. Chang, K. Długołęcki, J. Küpper, D. Rösch, D. Wild, and S. Willitsch, "Specific chemical reactivities of spatially separated 3-aminophenol conformers with cold Ca+ ions," Science 342, 98-101 (2013)]. Different conformers are spatially separated using inhomogeneous electric fields and reacted with a Coulomb crystal of cold, spatially localized ions in a trap. As a first application, we studied reactions between the two conformers of 3-aminophenol and Ca+. We observed a twofold larger rate constant for the cis compared to the trans conformer which was rationalized in terms of the differences in the long-range ion-molecule interactions. The present article provides a detailed description of the new method and a full account of the experimental results as well as the accompanying theoretical calculations.
Elastic scattering and reaction mechanisms of the halo nucleus $^{11}$Be around the Coulomb barrier
Di Pietro, A; Fisichella, M; Borge, M J G; Randisi, G; Milin, M; Figuera, P; Gomez-Camacho, J; Raabe, R; Amorini, F; Fraile, L M; Rizzo, F; Zadro, M; Torresi, D; Wenander, F; Pellegriti, M G; Papa, M; Jeppesen, H; Santonocito, D; Scuderi, V; Acosta, L; Perez-Bernal, F; Tengblad, O; Lattuada, M; Musumarra, A; Scalia, G; Maira Vidal, A; Voulot, D
2010-01-01
Collisions induced by $^{9}$Be, $^{10}$Be, $^{11}$Be on a $^{64}$Zn target at the same c. m. energy were studied. For the first time, strong effects of the $^{11}$Be halo structure on elastic-scattering and reaction mechanisms at energies near the Coulomb barrier are evidenced experimentally. The elastic-scattering cross section of the $^{11}$Be halo nucleus shows unusual behavior in the Coulomb-nuclear interference peak angular region. The extracted total-reaction cross section for the $^{11}$Be collision is more than double the ones measured in the collisions induced by $^{9}$Be, $^{10}$Be. It is shown that such a strong enhancement of the total-reaction cross section with $^{11}$Be is due to transfer and breakup processes.
Classical spectrum generating algebra of the Kepler–Coulomb system and action-angle variables
Energy Technology Data Exchange (ETDEWEB)
Kuru, Ş., E-mail: kuru@science.ankara.edu.tr [Department of Physics, Faculty of Science, Ankara University, 06100 Ankara (Turkey); Negro, J., E-mail: jnegro@fta.uva.es [Departamento de Física Teórica, Atómica y Óptica, Universidad de Valladolid, 47071 Valladolid (Spain)
2012-01-09
The classical spectrum generating algebra for the one-dimensional Kepler–Coulomb system is computed and a set of two corresponding constants of motion depending explicitly on time is obtained. Such constants supply the solution to the motion in an algebraic way. The connection of the spectrum generating algebra and the action-angle variables of the system is also shown. -- Highlights: ► The spectrum generating algebra for classical (and quantum) 1D Kepler–Coulomb problem is constructed. ► It allows to find constants of motion depending explicitly on time. ► It leads to an algebraic solution of the motion. ► This algebra is related to the action-angle variables of the classical system.
Anomalous low-temperature Coulomb drag in graphene-GaAs heterostructures.
Gamucci, A; Spirito, D; Carrega, M; Karmakar, B; Lombardo, A; Bruna, M; Pfeiffer, L N; West, K W; Ferrari, A C; Polini, M; Pellegrini, V
2014-12-19
Vertical heterostructures combining different layered materials offer novel opportunities for applications and fundamental studies. Here we report a new class of heterostructures comprising a single-layer (or bilayer) graphene in close proximity to a quantum well created in GaAs and supporting a high-mobility two-dimensional electron gas. In our devices, graphene is naturally hole-doped, thereby allowing for the investigation of electron-hole interactions. We focus on the Coulomb drag transport measurements, which are sensitive to many-body effects, and find that the Coulomb drag resistivity significantly increases for temperatures law, therefore displaying a notable departure from the ordinary quadratic temperature dependence expected in a weakly correlated Fermi-liquid. This anomalous behaviour is consistent with the onset of strong interlayer correlations. Our heterostructures represent a new platform for the creation of coherent circuits and topologically protected quantum bits.
Effect of Coulomb correlation on charge transport in disordered organic semiconductors
Liu, Feilong; van Eersel, Harm; Xu, Bojian; Wilbers, Janine G. E.; de Jong, Michel P.; van der Wiel, Wilfred G.; Bobbert, Peter A.; Coehoorn, Reinder
2017-11-01
Charge transport in disordered organic semiconductors, which is governed by incoherent hopping between localized molecular states, is frequently studied using a mean-field approach. However, such an approach only considers the time-averaged occupation of sites and neglects the correlation effect resulting from the Coulomb interaction between charge carriers. Here, we study the charge transport in unipolar organic devices using kinetic Monte Carlo simulations and show that the effect of Coulomb correlation is already important when the charge-carrier concentration is above 10-3 per molecular site and the electric field is smaller than 108 V/m. The mean-field approach is then no longer valid, and neglecting the effect can result in significant errors in device modeling. This finding is supported by experimental current density-voltage characteristics of ultrathin sandwich-type unipolar poly(3-hexylthiophene) (P3HT) devices, where high carrier concentrations are reached.
Directory of Open Access Journals (Sweden)
Nikola Jakšić
2014-01-01
Full Text Available The paper presents phase portraits of the autonomous Duffing single-degree-of-freedom system with Coulomb dry friction in its δ-γ-ε parameter space. The considered nonlinearities of the cubic stiffness (ε and Coulomb dry friction (γ are widely used throughout the literature. It has been shown that there can be more than one sticking region in the phase plane. It has also been shown that an equilibrium point occurs at the critical combinations of values of the parameters γ and ε which gives rise to zero eigenvalue of the linearised system. The unstable limit cycle may appear in the case of negative viscous damping (δ; δ<0.
Coulomb Excitation of Neutron Deficient Sn-Isotopes using REX-ISOLDE
Di julio, D D; Kownacki, J M; Marechal, F; Andreoiu, C; Siem, S; Perrot, F; Van duppen, P L E; Napiorkowski, P J; Iwanicki, J S
2002-01-01
It is proposed to study the evolution of the reduced transition probabilities, B(E2; 0$^{+} \\rightarrow$ 2$^{+}$), for neutron deficient Sn isotopes by Coulomb excitation in inverse kinematics using REX-ISOLDE and the MINIBALL detector array. Measurements of the reduced transition matrix element for the transition between the ground state and the first excited 2$^{+}$ state in light even-even Sn isotopes provide a means to study e.g. core polarization effects in the $^{100}$Sn core. Previous attempts to measure this quantity have been carried out using the decay of isomeric states populated in fusion evaporation reactions. We thus propose to utilize the unique opportunity provided by REX-ISOLDE, after the energy upgrade to 3.1 MeV/u, to use the more model-independent approach of Coulomb excitation to measure this quantity in a number of isotopes in this region.
First measurement with a new setup for low-energy Coulomb excitation studies at INFN LNL
Rocchini, M.; Hadyńska-Klȩk, K.; Nannini, A.; Valiente-Dobón, J. J.; Goasduff, A.; Testov, D.; John, P. R.; Mengoni, D.; Zielińska, M.; Bazzacco, D.; Benzoni, G.; Boso, A.; Cocconi, P.; Chiari, M.; Doherty, D. T.; Galtarossa, F.; Jaworski, G.; Komorowska, M.; Matejska-Minda, M.; Melon, B.; Menegazzo, R.; Napiorkowski, P.; Napoli, D. R.; Ottanelli, M.; Perego, A.; Ramina, L.; Rampazzo, M.; Recchia, F.; Riccetto, S.; Rosso, D.; Siciliano, M.; Sona, P.
2017-07-01
A new segmented particle detector, SPIDER, has been designed to be used as an ancillary device with the GALILEO γ-ray spectrometer, as well as with other multi-detector γ-ray arrays that will be available at LNL in the future (e.g. AGATA). To commission the SPIDER-GALILEO experimental setup, a multi-step Coulomb excitation experiment was carried out with a 240 MeV beam of 66Zn produced by the Tandem-XTU accelerator at INFN Laboratori Nazionali di Legnaro. The measured particle and γ-ray spectra are compared with the results of detailed GEANT4 simulations which used the Coulomb excitation cross sections, estimated with the computer code GOSIA, as an input. The preliminary results indicate that precise transition probabilities will be obtained which are essential for solving discrepancies reported in the literature for this nucleus.
Voltage fluctuation to current converter with Coulomb-coupled quantum dots.
Hartmann, F; Pfeffer, P; Höfling, S; Kamp, M; Worschech, L
2015-04-10
We study the rectification of voltage fluctuations in a system consisting of two Coulomb-coupled quantum dots. The first quantum dot is connected to a reservoir where voltage fluctuations are supplied and the second one is attached to two separate leads via asymmetric and energy-dependent transport barriers. We observe a rectified output current through the second quantum dot depending quadratically on the noise amplitude supplied to the other Coulomb-coupled quantum dot. The current magnitude and direction can be switched by external gates, and maximum output currents are found in the nA region. The rectification delivers output powers in the pW region. Future devices derived from our sample may be applied for energy harvesting on the nanoscale beneficial for autonomous and energy-efficient electronic applications.
Coulomb interactions-induced perfect spin-filtering effect in a quadruple quantum-dot cell
Kagan, M. Yu.; Val'kov, V. V.; Aksenov, S. V.
2017-10-01
A quadruple quantum-dot (QQD) cell is proposed as a spin filter. The transport properties of the QQD cell were studied in linear response regime on the basis of the equations of motion for retarded Green's functions. The developed approach allowed us to take into account the influence of both intra- and interdot Coulomb interactions on charge carriers' spin polarization. It was shown that the presence of the insulating bands in the conductance due to the Coulomb correlations results in the emergence of spin-polarized windows (SPWs) in magnetic field leading to the high spin polarization. We demonstrated that the SPWs can be effectively manipulated by gate fields and considering the hopping between central dots in both isotropic and anisotropic regimes.
Song, Xiaohong; Lin, Cheng; Sheng, Zhihao; Yu, Xianhuan; Yang, Weifeng; Hu, Shilin; Chen, Jing; Xu, SongPo; Chen, YongJu; Quan, Wei; Liu, XiaoJun
2016-01-01
A novel and universal interference structure is found in the photoelectron momentum distribution of atoms in intense infrared laser field. Theoretical analysis shows that this structure can be attributed to a new form of Coulomb-field-driven backward-scattering of photoelectrons in the direction perpendicular to the laser field, in contrast to the conventional rescattering along the laser polarization direction. This transverse backward-scattering process is closely related to a family of photoelectrons initially ionized within a time interval of less than 200 attosecond around the crest of the laser electric field. Those electrons, acquiring near-zero return energy in the laser field, will be pulled back solely by the ionic Coulomb field and backscattered in the transverse direction. Moreover, this rescattering process mainly occurs at the first or the second return times, giving rise to different phases of the photoelectrons. The interference between these photoelectrons leads to unique curved interference ...
Song, Xiaohong; Sheng, Zhihao; Liu, Peng; Chen, Zhangjin; Yang, Weifeng; Hu, Shilin; Lin, C D; Chen, Jing
2016-01-01
Strong field photoelectron holography has been proposed as a means for interrogating the spatial and temporal information of electrons and ions in a dynamic system. After ionization, part of the electron wave packet may directly go to the detector (the reference wave), while another part may be driven back to the ion where it scatters off (the signal wave). The interference hologram of the two waves may be used to retrieve the target information. However, unlike conventional optical holography, the propagations of electron wave packets are affected by the Coulomb potential as well as by the laser field. In addition, electrons are emitted over the whole laser pulse duration, thus multiple interferences may occur. In this work, we used a generalized quantum-trajectory Monte Carlo method to investigate the effect of Coulomb potential and the nonadiabatic subcycle ionization on the photoelectron hologram. We showed that photoelectron hologram can be well described only when the nonadiabatic effect in ionization i...
Deep Foundation Modeling with Morh-Coulomb Model in Dense Sands with Dilatancy
Directory of Open Access Journals (Sweden)
Darius Macijauskas
2011-04-01
Full Text Available The analysis of load distribution in deep foundations found in dense and indiscrete sand between base and shaft is considered in this paper. The availability of designing deep foundations in sand with dilatancy was studied with changing dilatancy angle. For design, Plaxis 3D Foundation v2 Morh-Coulomb model was used. Various load distributions between shaft and base were obtained when dilatancy angle varied from 0° to 5°. Skin friction increases significantly increasing dilatancy angle. However, in Mohr-Coulomb model, (drained conditions soil will continue to dilate as long as shear deformations occurs. This error decreases in case relative foundation length L/D and dilatancy angle ψ decrease. Article in Lithuanian
Energy Technology Data Exchange (ETDEWEB)
Hellgartner, Stefanie Christine
2015-11-13
In this work, the N=40 subshell closure is investigated with two complementary methods using a radioactive {sup 72}Zn ISOLDE beam: One- and two-neutron transfer reactions and multiple Coulomb excitation. In the one-neutron transfer reaction, two new levels of {sup 73}Zn were discovered. The two-neutron transfer channel allowed to study the differential cross section of the ground state and the 2{sup +}{sub 1} state of {sup 74}Zn. In the Coulomb excitation experiment, the measured B(E2) values and quadrupole moments of {sup 72}Zn showed that the yrast states 0{sup +}{sub 1}, 2{sup +}{sub 1} and 4{sup +}{sub 1} are moderately collective. Contrary, the 0{sup +}{sub 2} state has a different structure, since it features a stronger closed N=40 configuration compared to the ground state.
Coulomb-explosion imaging of concurrent CH2BrI photodissociation dynamics
Burt, Michael; Boll, Rebecca; Lee, Jason W. L.; Amini, Kasra; Köckert, Hansjochen; Vallance, Claire; Gentleman, Alexander S.; Mackenzie, Stuart R.; Bari, Sadia; Bomme, Cédric; Düsterer, Stefan; Erk, Benjamin; Manschwetus, Bastian; Müller, Erland; Rompotis, Dimitrios; Savelyev, Evgeny; Schirmel, Nora; Techert, Simone; Treusch, Rolf; Küpper, Jochen; Trippel, Sebastian; Wiese, Joss; Stapelfeldt, Henrik; de Miranda, Barbara Cunha; Guillemin, Renaud; Ismail, Iyas; Journel, Loïc; Marchenko, Tatiana; Palaudoux, Jérôme; Penent, Francis; Piancastelli, Maria Novella; Simon, Marc; Travnikova, Oksana; Brausse, Felix; Goldsztejn, Gildas; Rouzée, Arnaud; Géléoc, Marie; Geneaux, Romain; Ruchon, Thierry; Underwood, Jonathan; Holland, David M. P.; Mereshchenko, Andrey S.; Olshin, Pavel K.; Johnsson, Per; Maclot, Sylvain; Lahl, Jan; Rudenko, Artem; Ziaee, Farzaneh; Brouard, Mark; Rolles, Daniel
2017-10-01
The dynamics following laser-induced molecular photodissociation of gas-phase CH2BrI at 271.6 nm were investigated by time-resolved Coulomb-explosion imaging using intense near-IR femtosecond laser pulses. The observed delay-dependent photofragment momenta reveal that CH2BrI undergoes C-I cleavage, depositing 65.6% of the available energy into internal product states, and that absorption of a second UV photon breaks the C-Br bond of CH2Br . Simulations confirm that this mechanism is consistent with previous data recorded at 248 nm, demonstrating the sensitivity of Coulomb-explosion imaging as a real-time probe of chemical dynamics.
Spectra for the A = 6 reactions calculated from a three-body resonance model
Paris, Mark W.; Hale, Gerald M.
2016-06-01
We develop a resonance model of the transition matrix for three-body breakup reactions of the A = 6 system and present calculations for the nucleon observed spectra, which are important for inertial confinement fusion and Big Bang nucleosynthesis (BBN). The model is motivated by the Faddeev approach where the form of the T matrix is written as a sum of the distinct Jacobi coordinate systems corresponding to particle configurations (α, n-n) and (n; n-α) to describe the final state. The structure in the spectra comes from the resonances of the two-body subsystems of the three-body final state, namely the singlet (T = 1) nucleon-nucleon (NN) anti-bound resonance, and the Nα resonances designated the ground state (Jπ = {{{3^ - }} over 2}) and first excited state (Jπ = {{{1^ - }} over 2}) of the A = 5 systems 5He and 5Li. These resonances are described in terms of single-level, single-channel R-matrix parameters that are taken from analyses of NN and Nα scattering data. While the resonance parameters are approximately charge symmetric, external charge-dependent effects are included in the penetrabilities, shifts, and hard-sphere phases, and in the level energies to account for internal Coulomb differences. The shapes of the resonance contributions to the spectrum are fixed by other, two-body data and the only adjustable parameters in the model are the combinatorial amplitudes for the compound system. These are adjusted to reproduce the observed nucleon spectra from measurements at the Omega and NIF facilities. We perform a simultaneous, least-squares fit of the tt neutron spectra and the 3He3He proton spectra. Using these amplitudes we make a prediction of the α spectra for both reactions at low energies. Significant differences in the tt and 3He3He spectra are due to Coulomb effects.
Spectra for the A = 6 reactions calculated from a three-body resonance model
Directory of Open Access Journals (Sweden)
Paris Mark W.
2016-01-01
Full Text Available We develop a resonance model of the transition matrix for three-body breakup reactions of the A = 6 system and present calculations for the nucleon observed spectra, which are important for inertial confinement fusion and Big Bang nucleosynthesis (BBN. The model is motivated by the Faddeev approach where the form of the T matrix is written as a sum of the distinct Jacobi coordinate systems corresponding to particle configurations (α, n-n and (n; n-α to describe the final state. The structure in the spectra comes from the resonances of the two-body subsystems of the three-body final state, namely the singlet (T = 1 nucleon-nucleon (NN anti-bound resonance, and the Nα resonances designated the ground state (Jπ = 3−2${{{3^ - }} \\over 2}$ and first excited state (Jπ = 1−2${{{1^ - }} \\over 2}$ of the A = 5 systems 5He and 5Li. These resonances are described in terms of single-level, single-channel R-matrix parameters that are taken from analyses of NN and Nα scattering data. While the resonance parameters are approximately charge symmetric, external charge-dependent effects are included in the penetrabilities, shifts, and hard-sphere phases, and in the level energies to account for internal Coulomb differences. The shapes of the resonance contributions to the spectrum are fixed by other, two-body data and the only adjustable parameters in the model are the combinatorial amplitudes for the compound system. These are adjusted to reproduce the observed nucleon spectra from measurements at the Omega and NIF facilities. We perform a simultaneous, least-squares fit of the tt neutron spectra and the 3He3He proton spectra. Using these amplitudes we make a prediction of the α spectra for both reactions at low energies. Significant differences in the tt and 3He3He spectra are due to Coulomb effects.
Considerations on elliptical failure envelope associated to Mohr-Coulomb criterion
Comanici, A. M.; Barsanescu, P. D.
2016-08-01
Mohr-Coulomb theory is mostly used in civil engineering as it is suitable for soils, rock, concretes, etc., meaning that the theory is generally used for brittle facture of the materials, but there are cases when it matches ductile behaviour also. The failure envelope described by the Mohr-Coulomb criterion is not completely accurate to the real yield envelope. The ductile or brittle behaviour of materials could not be incorporated in a linear envelope suggested by classic stress state theories and so, there have been a number of authors who have refined the notion of yield envelope so that it would fit better to the actual behaviour of materials. The need of a realistic yield envelope comes from the demand that the failure state should be able to be predicted in a fair manner and with as little errors as possible. Of course, certain criteria will be closer to the actual situation, but there is a constant need to unify and refine the limit stress theories in order to avoid problems as defining boundaries of application areas on numerical programs. Mohr-Coulomb's yield envelope is the most used one on programs, can be reduced to Tresca theory when the materials are conducting a ductile behaviour and has a linear simplified form. The paper presents some considerations with respect to the elliptical failure envelope correlated to the Mohr-Coulomb theory. The equations have been rewritten for triaxial situation to describe a more accurate state of stress that is encountered under real conditions in materials. Using the Mohr's circles to define the yield envelope, the calculus has been made in in order to determine the yield stress at tensile tests
Use of Lambert's Theorem for the n-Dimensional Coulomb Problem
Kanellopoulos, Vassiliki; Kleber, Manfred; Kramer, Tobias
2009-01-01
We present the analytical solution in closed form for the semiclassical limit of the quantum mechanical Coulomb Green function in position space in n dimensions. We utilize a projection method which has its roots in Lambert's theorem and which allows us to treat the system as an essentially one dimensional problem. The semiclassical result assumes a simple analytical form and is well suited for a numerical evaluation. The method can also be extended to classically forbidden space regions. Alr...
Paulsen, C.; Giblin, S. R.; Lhotel, E.; Prabhakaran, D.; Balakrishnan, Geetha; Matsuhira, K.; Bramwell, S. T.
2016-01-01
A non-Ohmic current that grows exponentially with the square root of applied electric field is well known from thermionic field emission (the Schottky effect)1, electrolytes (the second Wien effect)2 and semiconductors (the Poole–Frenkel effect)3. It is a universal signature of the attractive Coulomb force between positive and negative electrical charges, which is revealed as the charges are driven in opposite directions by the force of an applied electric field. Here we apply thermal quenche...
Chabot, Marin; Béroff, Karine; Dartois, Emmanuel; Pino, Thomas; Godard, Marie
2017-01-01
Cosmic Rays (CR) process the matter of the Interstellar Medium. Such energetic processing not only modifies the interstellar matter but also injects chemical species in the gas phase. In this work, we study the effect of the CR on the astrophysical polycyclic aromatic hydrocarbons (PAH). For events in which many electrons are stripped out from the PAH by interaction with a heavy cosmic ray particle, coulomb explosion takes place and carbon chains are produced. The fragments production rates o...
Derivation of the nonlinear Schrödinger equation with a Coulomb potential
Erdos, L
2001-01-01
We consider the time evolution of $N$ bosonic particles interacting via a mean field Coulomb potential. Suppose the initial state is a product wavefunction. We show that at any finite time the correlation functions factorize in the limit $N \\to \\infty$. Furthermore, the limiting one particle density matrix satisfies the nonlinear Hartree equation. The key ingredients are the uniqueness of the BBGKY hierarchy for the correlation functions and a new apriori estimate for the many-body Schrödinger equations.
Fusion of sup 64 Ni+ sup 92,96 Zr near and below the Coulomb barrier
Energy Technology Data Exchange (ETDEWEB)
Stefanini, A.M.; Corradi, L.; Moreno, H.; Mueller, L.; Napoli, D.R.; Spolaore, P.; Adamides, E. (Istituto Nazionale di Fisica Nucleare, Padua (Italy). Lab. di Legnaro); Beghini, S.; Segato, G.F.; Soramel, F. (Padua Univ. (Italy). Dipt. di Fisica Istituto Nazionale di Fisica Nucleare, Padua (Italy)); Signorini, C. (Salerno Univ. (Italy). Dipt. di Fisica Istituto Nazionale di Fisica Nucleare, Padua (Italy))
1990-12-06
Evaporation residue cross sections have been measured for the two systems {sup 64}Ni + {sup 92,96}Zr around and below the Coulomb barrier. The data for {sup 96}Zr near the barrier agree within the errors with previously published results, whereas a large discrepancy is found for {sup 92}Zr over all the energy range. Important consequences follow in the interpretation of recently measured compound nucleus spin distributions at energies slightly higher than the barrier. (orig.).
Fluctuation of average position of electrons in Coulomb island in Si single-electron transistor
Energy Technology Data Exchange (ETDEWEB)
Horiguchi, Seiji, E-mail: seijih@ipc.akita-u.ac.jp [Graduate School of Engineering and Resource Sciense, Akita University, 1-1 Tegata-gakuen-machi, Akita-shi, Akita, 010-8502 Japan (Japan); Fujiwara, Akira [NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa, 243-0198 Japan (Japan)
2012-02-01
Average position of electrons along thickness direction in a Coulomb island in an n-channel Si single-electron transistor is estimated by analyzing the back-gate voltage dependence of peak voltage (defined as the gate voltage giving a drain current peak) as a function of peak number. It is found that the accuracy of estimated average position is better than 0.5 nm and that the average position fluctuates as the peak number increases.
Structure Theory for Extended Kepler-Coulomb 3D Classical Superintegrable Systems
Directory of Open Access Journals (Sweden)
Ernie G. Kalnins
2012-06-01
Full Text Available The classical Kepler-Coulomb system in 3 dimensions is well known to be 2nd order superintegrable, with a symmetry algebra that closes polynomially under Poisson brackets. This polynomial closure is typical for 2nd order superintegrable systems in 2D and for 2nd order systems in 3D with nondegenerate (4-parameter potentials. However the degenerate 3-parameter potential for the 3D extended Kepler-Coulomb system (also 2nd order superintegrable is an exception, as its quadratic symmetry algebra doesn't close polynomially. The 3D 4-parameter potential for the extended Kepler-Coulomb system is not even 2nd order superintegrable. However, Verrier and Evans (2008 showed it was 4th order superintegrable, and Tanoudis and Daskaloyannis (2011 showed that in the quantum case, if a second 4th order symmetry is added to the generators, the double commutators in the symmetry algebra close polynomially. Here, based on the Tremblay, Turbiner and Winternitz construction, we consider an infinite class of classical extended Kepler-Coulomb 3- and 4-parameter systems indexed by a pair of rational numbers (k_1,k_2 and reducing to the usual systems when k_1=k_2=1. We show these systems to be superintegrable of arbitrarily high order and work out explicitly the structure of the symmetry algebras determined by the 5 basis generators we have constructed. We demonstrate that the symmetry algebras close rationally; only for systems admitting extra discrete symmetries is polynomial closure achieved. Underlying the structure theory is the existence of raising and lowering constants of the motion, not themselves polynomials in the momenta, that can be employed to construct the polynomial symmetries and their structure relations.
Coulomb interaction and phonons in doped semiconducting and metallic two-dimensional materials
Schönhoff, Gunnar
2017-01-01
Two-dimensional (2D) materials present a rapidly developing field of research with sometimes highly unusual and uniquely two-dimensional physics. Starting with graphene, many recent studies have investigated 2D materials, with results for properties encompassing such different topics as Dirac electrons, charge ordering, and superconductivity. To get closer to a predictive theory of the phases of 2D materials, this thesis systematically tackles the previously unclear problem of the Coulomb int...
Electron Dynamics of Interatomic Coulombic Decay in Quantum Dots: Singlet Initial State
Directory of Open Access Journals (Sweden)
Cederbaum Lorenz S.
2013-03-01
Full Text Available In this paper we investigated the interatomic Coulombic decay (ICD of a resonance singlet state in a model potential for two few-electron semiconductor quantum dots (QDs by means of electron dynamics. We demonstrate that ICD is the major decay process of the resonance for the singlet wave function and compare the total and partial decay widths as a function of the QD separation with that from our previous study on the corresponding triplet states [1].
Quasi-Exact Coulomb Dynamics of n Charges n-1 of Which Are Equal
Directory of Open Access Journals (Sweden)
Wolodymyr Skrypnik
2017-01-01
Full Text Available For n≥3 point charges n-1 of which are negative and equal quasi-exact periodic solutions of their Coulomb equation of motion are found. These solutions describe a motion of the negative charges around a coordinate axis in such a way that their coordinates coincide with vertices of a regular polygon in planes perpendicular to the axis along which the positive charge moves. The Weinstein and center Lyapunov theorems are utilized.
Quasi-Exact Coulomb Dynamics of n + 1 Charges n - 1 of which are Equal
Skrypnik, W. I.
2017-08-01
For n + 1 ≥ 4 point charges n - 1 of which are negative and equal quasi-exact periodic solutions of their Coulomb equation of motion are found. These solutions describe a motion of the negative charges around the vertical axis in such a way that their coordinates coincide with vertices of a regular polygon in planes perpendicular to the axis along which two equal positive charges move.
Directory of Open Access Journals (Sweden)
Vitaly P. Kim
2015-06-01
Full Text Available In this paper we study the transmission of the electrostatic field due to coulomb charges of an individual thundercloud into the midlatitude ionosphere, taking into account the total geomagnetic field integrated Pedersen conductivity of the ionosphere. It is shown that at ionospheric altitudes, a typical thundercloud produces an insignificant electrostatic field whereas a giant thundercloud can drive the horizontal electrostatic field with a magnitude of ~270 μV/m for nighttime conditions.
Stability of Coulomb crystals in a linear Paul trap with storage-ring-like confinement
DEFF Research Database (Denmark)
Kjærgaard, Niels; Mølhave, Kristian; Drewsen, Michael
2002-01-01
We report experiments on the stability of ion Coulomb crystals in a linear Paul trap with storage-ring-like confinement. The transverse dynamics of charged particles in a trap of this type is analogous to that of a fast beam traveling through a channel with periodic, magnetic alternating gradient...... confinement. The experimentally observed stability conditions for stationary crystals comply remarkably well with current theory of crystalline plasmas and beams....
Probing shape coexistence in neutron-deficient $^{72}$Se via low-energy Coulomb excitation
We propose to study the evolution of nuclear structure in neutron-deficient $^{72}$Se by performing a low-energy Coulomb excitation measurement. Matrix elements will be determined for low-lying excited states allowing for a full comparison with theoretical predictions. Furthermore, the intrinsic shape of the ground state, and the second 0$^{+}$ state, will be investigated using the quadrupole sum rules method.
Current conservation and ratio rules in magnetic metals with Coulomb repulsion
Odagiri, Kosuke
2011-01-01
From general considerations of spin-symmetry breaking associated with (anti-)ferromagnetism in metallic systems with Coulomb repulsion, we obtain interesting and simple all-order rules involving the ratios of the densities of states. These are exact for ferromagnetism under reasonable conditions, and nearly exact for anti-ferromagnetism. In the case of ferromagnetism, the comparison with the available experimental and theoretical numbers yields favourable results.
Coulomb-distorted plane wave: Partial wave expansion and asymptotic forms
Hornyak, I.; Kruppa, A. T.
2013-05-01
Partial wave expansion of the Coulomb-distorted plane wave is determined and studied. Dominant and sub-dominant asymptotic expansion terms are given and leading order three-dimensional asymptotic form is derived. The generalized hypergeometric function 2F2(a, a; a + l + 1, a - l; z) is expressed with the help of confluent hypergeometric functions and the asymptotic expansion of 2F2(a, a; a + l + 1, a - l; z) is simplified.
Effect of Coulomb collision on the negative ion extraction mechanism in negative ion sources
Energy Technology Data Exchange (ETDEWEB)
Goto, I., E-mail: goto@ppl.appi.keio.ac.jp; Nishioka, S.; Abe, S.; Hatayama, A. [Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Miyamoto, K. [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan); Mattei, S.; Lettry, J. [CERN, 1211 Geneva 23 (Switzerland)
2016-02-15
To improve the H{sup −} ion beam optics, it is necessary to understand the energy relaxation process of surface produced H{sup −} ions in the extraction region of Cs seeded H{sup −} ion sources. Coulomb collisions of charged particles have been introduced to the 2D3V-PIC (two dimension in real space and three dimension in velocity space particle-in-cell) model for the H{sup −} extraction by using the binary collision model. Due to Coulomb collision, the lower energy part of the ion energy distribution function of H{sup −} ions has been greatly increased. The mean kinetic energy of the surface produced H{sup −} ions has been reduced to 0.65 eV from 1.5 eV. It has been suggested that the beam optics of the extracted H{sup −} ion beam is strongly affected by the energy relaxation process due to Coulomb collision.
Directory of Open Access Journals (Sweden)
Fu Ying-Jhe
2010-01-01
Full Text Available Abstract We report on the diamagnetic responses of different exciton complexes in single InAs/GaAs self-assembled quantum dots (QDs and quantum rings (QRs. For QDs, the imbalanced magnetic responses of inter-particle Coulomb interactions play a crucial role in the diamagnetic shifts of excitons (X, biexcitons (XX, and positive trions (X−. For negative trions (X− in QDs, anomalous magnetic responses are observed, which cannot be described by the conventional quadratic energy shift with the magnetic field. The anomalous behavior is attributed to the apparent change in the electron wave function extent after photon emission due to the strong Coulomb attraction by the hole in its initial state. In QRs, the diamagnetic responses of X and XX also show different behaviors. Unlike QDs, the diamagnetic shift of XX in QRs is considerably larger than that of X. The inherent structural asymmetry combined with the inter-particle Coulomb interactions makes the wave function distribution of XX very different from that of X in QRs. Our results suggest that the phase coherence of XX in QRs may survive from the wave function localization due to the structural asymmetry or imperfections.
Thermal and chaotic distributions of plasma in laser driven Coulomb explosions of deuterium clusters
Barbarino, M; Bonasera, A; Lattuada, D; Bang, W; Quevedo, H J; Consoli, F; De Angelis, R; Andreoli, P; Kimura, S; Dyer, G; Bernstein, A C; Hagel, K; Barbui, M; Schmidt, K; Gaul, E; Donovan, M E; Natowitz, J B; Ditmire, T
2015-01-01
In this work we explore the possibility that the motion of the deuterium ions emitted from Coulomb cluster explosions is chaotic enough to resemble thermalization. We analyze the process of nuclear fusion reactions driven by laser-cluster interactions in experiments conducted at the Texas Petawatt laser facility using a mixture of D2+3He and CD4+3He cluster targets. When clusters explode by Coulomb repulsion, the emission of the energetic ions is nearly isotropic. In the framework of cluster Coulomb explosions, we analyze the energy distributions of the ions using a Maxwell- Boltzmann (MB) distribution, a shifted MB distribution (sMB) and the energy distribution derived from a log-normal (LN) size distribution of clusters. We show that the first two distributions reproduce well the experimentally measured ion energy distributions and the number of fusions from d-d and d-3He reactions. The LN distribution is a good representation of the ion kinetic energy distribution well up to high momenta where the noise be...
Coulomb breakup of the neutron-rich isotopes {sup 15}C and {sup 17}C
Energy Technology Data Exchange (ETDEWEB)
Datta Pramanik, U.; Aumann, T.; Boretzky, K.; Carlson, B.V.; Cortina, D.; Elze, Th.W.; Emling, H.; Geissel, H.; Gruenschloss, A.; Hellstroem, M.; Ilievski, S.; Kratz, J.V.; Kulessa, R.; Leifels, Y.; Leistenschneider, A.; Lubkiewicz, E.; Muenzenberg, G.; Reiter, P.; Simon, H.; Suemmerer, K.; Wajda, E.; Walus, W
2003-01-02
Coulomb breakup of unstable neutron-rich carbon isotopes {sup 15,17}C has been studied at energies around {approx}500-600 MeV/nucleon. Non-resonant low-lying dipole strength is observed in these isotopes which can be explained by a direct breakup mechanism. In addition to the decay neutron from excited projectile, {gamma}-rays emitted from excited fragments after Coulomb breakup are measured in coincidence, giving access to quantitative spectroscopic information. The spectroscopic factor deduced for a valence neutron occupying the s{sub 1/2} level in the {sup 15}C ground state is consistent with that obtained earlier from (d,p) transfer reactions. The analysis for Coulomb breakup of {sup 17}C shows that most of the cross section yields the {sup 16}C core in excited states. The predominant ground-state configuration of {sup 17}C is found to be {sup 16}C(2{sup +}) x {nu}{sub sd}.
Energy Technology Data Exchange (ETDEWEB)
Clement, E. [CEA Saclay, DSM/DAPNIA/SPhN, F-91191 Gif-sur-Yvette (France); GANIL, BP-5027, F-14076 Caen Cedex (France); Goergen, A. [CEA Saclay, DSM/DAPNIA/SPhN, F-91191 Gif-sur-Yvette (France)], E-mail: andreas.goergen@cea.fr; Korten, W. [CEA Saclay, DSM/DAPNIA/SPhN, F-91191 Gif-sur-Yvette (France); Buerger, A. [CEA Saclay, DSM/DAPNIA/SPhN, F-91191 Gif-sur-Yvette (France); Helmholtz-Institut fuer Strahlen- und Kernphysik, Universitaet Bonn, D-53115 Bonn (Germany); Chatillon, A.; Le Coz, Y.; Theisen, Ch. [CEA Saclay, DSM/DAPNIA/SPhN, F-91191 Gif-sur-Yvette (France); Zielinska, M. [CEA Saclay, DSM/DAPNIA/SPhN, F-91191 Gif-sur-Yvette (France); Heavy Ion Laboratory, Warsaw University, Warsaw PL-02097 (Poland); Blank, B. [CEN Bordeaux-Gradignan, Universite Bordeaux I-CNRS/IN2P3, F-33175 Gradignan Cedex (France); Davies, P.J.; Fox, S.P. [Department of Physics, University of York, York YO10 5DD (United Kingdom); Gerl, J. [Gesellschaft fuer Schwerionenforschung, D-64291 Darmstadt (Germany); Georgiev, G.; Grevy, S. [GANIL, BP-5027, F-14076 Caen Cedex (France); Iwanicki, J. [Heavy Ion Laboratory, Warsaw University, Warsaw PL-02097 (Poland); Jenkins, D.G.; Johnston-Theasby, F.; Joshi, P. [Department of Physics, University of York, York YO10 5DD (United Kingdom); Matea, I. [CEN Bordeaux-Gradignan, Universite Bordeaux I-CNRS/IN2P3, F-33175 Gradignan Cedex (France); Napiorkowski, P.J. [Heavy Ion Laboratory, Warsaw University, Warsaw PL-02097 (Poland)] (and others)
2008-03-21
A new setup has been designed to perform Coulomb excitation experiments with fragmentation beams at intermediate energy and to measure at the same time conversion electrons from isomeric states populated in the fragmentation reaction. The newly designed setup is described and experimental results from a first experiment are shown. Radioactive even-even nuclei in the mass region A{approx_equal}70 close to the N=Z line were Coulomb excited after fragmentation of an intense primary {sup 78}Kr beam and selection in flight with the LISE3 spectrometer at GANIL. The {gamma} rays emitted after Coulomb excitation were detected in an array of four large segmented HPGe clover detectors in a very close geometry. The scattered ions were identified in a stack of highly segmented annular silicon detectors combined with a time-of-flight measurement using beam tracking detectors. Conversion electrons from isomeric 0{sub 2}{sup +} states decaying via electric monopole transitions were detected in an array of segmented cooled silicon detectors surrounding a telescope of plastic scintillators. Reduced transitions probabilities B(E2;0{sub 1}{sup +}{yields}2{sub 1}{sup +}) were deduced for several stable and radioactive nuclei.
Letting students discover the power, and the limits, of simple models: Coulomb's law
Bohacek, Peter; Vonk, Matthew; Dill, Joseph; Boehm, Emma
2017-09-01
The inverse-square law pops up all over. It's a simplified model of reality that describes light, sound, gravity, and static electricity. But when it's brought up in class, students are often just handed the equations. They rarely have an opportunity to discover Coulomb's law or Newton's law of gravitation for themselves. It's not hard to understand why. A quantitative demonstration of Coulomb's law can be difficult. The forces are smaller than many force sensors can measure and static electricity tends to be finicky. In addition, off-the-shelf units are expensive or difficult to use. As a result, many instructors skip this lab in favor of qualitative demonstrations or simulations. Adolf Cortel sought to remedy this by designing a straightforward experiment for measuring Coulomb's law using charged metalized-glass spheres (Christmas ornaments) and an electronic balance. Building on Cortel's design, we've made a series of video-based experiments that students can use to discover the relationships that underlie electric force.
Finite size and Coulomb corrections: from nuclei to nuclear liquid vapor phase diagram
Energy Technology Data Exchange (ETDEWEB)
Moretto, L.G.; Elliott, J.B.; Phair, L. [Lawrence Berkeley National Laboratory, Nuclear Science Division (United States)
2003-07-01
In this paper we consider the problem of obtaining the infinite symmetric uncharged nuclear matter phase diagram from a thermal nuclear reaction. In the first part we shall consider the Coulomb interaction which, because of its long range makes the definition of phases problematic. This Coulomb effect seems truly devastating since it does not allow one to define nuclear phase transitions much above A {approx} 30. However there may be a solution to this difficulty. If we consider the emission of particles with a sizable charge, we notice that a large Coulomb barrier Bc is present. For T << Bc these channels may be considered effectively closed. Consequently the unbound channels may not play a role on a suitably short time scale. Then a phase transition may still be definable in an approximate way. In the second part of the article we shall deal with the finite size problem by means of a new method, the complement method, which shall permit a straightforward extrapolation to the infinite system. The complement approach consists of evaluating the change in free energy occurring when a particle or cluster is moved from one (finite) phase to another. In the case of a liquid drop in equilibrium with its vapor, this is done by extracting a vapor particle of any given size from the drop and evaluating the energy and entropy changes associated with both the vapor particle and the residual liquid drop (complement)
On the Coulomb and Higgs branch formulae for multi-centered black holes and quiver invariants
Manschot, Jan; Sen, Ashoke
2013-01-01
In previous work we have shown that the equivariant index of multi-centered N=2 black holes localizes on collinear configurations along a fixed axis. Here we provide a general algorithm for enumerating such collinear configurations and computing their contribution to the index. We apply this machinery to the case of black holes described by quiver quantum mechanics, and give a systematic prescription -- the Coulomb branch formula -- for computing the cohomology of the moduli space of quiver representations. For quivers without oriented loops, the Coulomb branch formula is shown to agree with the Higgs branch formula based on Reineke's result for stack invariants, even when the dimension vector is not primitive. For quivers with oriented loops, the Coulomb branch formula parametrizes the Poincar\\'e polynomial of the quiver moduli space in terms of single-centered (or pure-Higgs) BPS invariants, which are conjecturally independent of the stability condition (i.e. the choice of Fayet-Iliopoulos parameters) and a...
Shape coexistence in the neutron-deficient mercury isotopes studied through Coulomb excitation
Bree, Nick
This thesis describes the analysis and results of a series of Coulomb-excitation experiments on even-even neutron-deficient mercury isotopes aimed at obtaining a more detailed description of shape coexistence. Two experimental campaigns have been undertaken in the Summer of 2007 and 2008. Pure beams of 182,184,186,188Hg were produced and accelerated at the REX-ISOLDE radioactive-beam facility, located at CERN (Geneva, Switzerland). The beams were guided to collide with a stable target to induce Coulomb excitation. The scattered particles were registered by a double-sided silicon strip detector, and the emitted gamma rays by the MINIBALL gamma-ray spectrometer. The motivation to study these mercury isotopes, focused around shape coexistence in atomic nuclei, is addressed in chapter 1, as well as an overview of the knowledge in this region of the nuclear chart. A theoretical description of Coulomb excitation is presented in the second chapter, while the third chapter describes the setup employed for the experim...
No evidence of reduced collectivity in Coulomb-excited Sn isotopes
Kumar, R.; Saxena, M.; Doornenbal, P.; Jhingan, A.; Banerjee, A.; Bhowmik, R. K.; Dutt, S.; Garg, R.; Joshi, C.; Mishra, V.; Napiorkowski, P. J.; Prajapati, S.; Söderström, P.-A.; Kumar, N.; Wollersheim, H.-J.
2017-11-01
In a series of Coulomb excitation experiments the first excited 2+ states in semimagic Sn 112 ,116 ,118 ,120 ,122 ,124 isotopes were excited using a 58Ni beam at safe Coulomb energy. The B (E 2 ; 0+→2+) values were determined with high precision (˜3 %) relative to 58Ni projectile excitation. These results disagree with previously reported B (E 2 ↑) values [A. Jungclaus et al., Phys. Lett. B 695, 110 (2011)., 10.1016/j.physletb.2010.11.012] extracted from Doppler-shift attenuation lifetime measurements, whereas the reported mass dependence of B (E 2 ↑) values is very similar to a recent Coulomb excitation study [J. M. Allmond et al., Phys. Rev. C 92, 041303(R) (2015), 10.1103/PhysRevC.92.041303]. The stable Sn isotopes, key nuclei in nuclear structure, show no evidence of reduced collectivity and we, thus, reconfirm the nonsymmetric behavior of reduced transition probabilities with respect to the midshell A =116 .
Higgs transition from a magnetic Coulomb liquid to a ferromagnet in Yb₂Ti₂O₇.
Chang, Lieh-Jeng; Onoda, Shigeki; Su, Yixi; Kao, Ying-Jer; Tsuei, Ku-Ding; Yasui, Yukio; Kakurai, Kazuhisa; Lees, Martin Richard
2012-01-01
In a class of frustrated magnets known as spin ice, magnetic monopoles emerge as classical defects and interact via the magnetic Coulomb law. With quantum-mechanical interactions, these magnetic charges are carried by fractionalized bosonic quasi-particles, spinons, which can undergo Bose-Einstein condensation through a first-order transition via the Higgs mechanism. Here, we report evidence of a Higgs transition from a magnetic Coulomb liquid to a ferromagnet in single-crystal Yb(2)Ti(2)O(7). Polarized neutron scattering experiments show that the diffuse [111]-rod scattering and pinch-point features, which develop on cooling are suddenly suppressed below T(C)~0.21 K, where magnetic Bragg peaks and a full depolarization of the neutron spins are observed with thermal hysteresis, indicating a first-order ferromagnetic transition. Our results are explained on the basis of a quantum spin-ice model, whose high-temperature phase is effectively described as a magnetic Coulomb liquid, whereas the ground state shows a nearly collinear ferromagnetism with gapped spin excitations.
Song, Xiaohong; Lin, Cheng; Sheng, Zhihao; Liu, Peng; Chen, Zhangjin; Yang, Weifeng; Hu, Shilin; Lin, C D; Chen, Jing
2016-06-22
Strong field photoelectron holography has been proposed as a means for interrogating the spatial and temporal information of electrons and ions in a dynamic system. After ionization, part of the electron wave packet may directly go to the detector (the reference wave), while another part may be driven back and scatters off the ion(the signal wave). The interference hologram of the two waves may be used to extract target information embedded in the collision process. Unlike conventional optical holography, however, propagation of the electron wave packet is affected by the Coulomb potential as well as by the laser field. In addition, electrons are emitted over the whole laser pulse duration, thus multiple interferences may occur. In this work, we used a generalized quantum-trajectory Monte Carlo method to investigate the effect of Coulomb potential and the nonadiabatic subcycle ionization on the photoelectron hologram. We showed that photoelectron hologram can be well described only when the effect of nonadiabatic ionization is accounted for, and Coulomb potential can be neglected only in the tunnel ionization regime. Our results help paving the way for establishing photoelectron holography for probing spatial and dynamic properties of atoms and molecules.
Self-Consistent Monte Carlo Study of the Coulomb Interaction under Nano-Scale Device Structures
Sano, Nobuyuki
2011-03-01
It has been pointed that the Coulomb interaction between the electrons is expected to be of crucial importance to predict reliable device characteristics. In particular, the device performance is greatly degraded due to the plasmon excitation represented by dynamical potential fluctuations in high-doped source and drain regions by the channel electrons. We employ the self-consistent 3D Monte Carlo (MC) simulations, which could reproduce both the correct mobility under various electron concentrations and the collective plasma waves, to study the physical impact of dynamical potential fluctuations on device performance under the Double-gate MOSFETs. The average force experienced by an electron due to the Coulomb interaction inside the device is evaluated by performing the self-consistent MC simulations and the fixed-potential MC simulations without the Coulomb interaction. Also, the band-tailing associated with the local potential fluctuations in high-doped source region is quantitatively evaluated and it is found that the band-tailing becomes strongly dependent of position in real space even inside the uniform source region. This work was partially supported by Grants-in-Aid for Scientific Research B (No. 2160160) from the Ministry of Education, Culture, Sports, Science and Technology in Japan.
Pandit, Rishi; Sentoku, Yasuhiko; Sawada, Hiroshi; Ramunno, Lora; Ackad, Edward
2017-10-01
An intense, short laser pulse incident on rare-gas clusters can produce nano-plasmas containing energetic electrons. As these electrons undergo scattering, both from phonons and ions, they emit bremsstrahlung radiation. Here we compare a theory of Bremsstrahlung emission appropriate for the interaction of intense lasers with matter using soft-core potentials and coulombic potential. A new scaling for the radiation cross-section and Emissivity via bremsstrahlung are derived for soft-core potential which depends on the potential depth, used to avoid coulomb singularity and for coulombic potential and implemented in a particle in cell code (PICLS). The radiation cross-section and emissivity via bremsstrahlung is found to increase rapidly with increases in potential depth up to 100 eV and then becomes mostly saturated for larger depths of a soft-core potential. For both cases, the radiation cross-section and emissivity of Bremsstrahlung increases with increases in laser wavelength. The bremsstrahlung emission may provide a broadband light source for diagnostics. This work was supported by Air Force Office of Scientific Research under AFOSR Award No. FA9550-14-1-0247.
National Research Council Canada - National Science Library
Bohigas, Xavier; Periago, Maria Cristina
2010-01-01
El presente estudio tiene como objetivo identificar los modelos mentales que aplican los estudiantes al iniciar el segundo curso de ingenieria cuando utilizan la Ley de Coulomb y el concepto de campo...
INVAP's Nuclear Calculation System
Directory of Open Access Journals (Sweden)
Ignacio Mochi
2011-01-01
Full Text Available Since its origins in 1976, INVAP has been on continuous development of the calculation system used for design and optimization of nuclear reactors. The calculation codes have been polished and enhanced with new capabilities as they were needed or useful for the new challenges that the market imposed. The actual state of the code packages enables INVAP to design nuclear installations with complex geometries using a set of easy-to-use input files that minimize user errors due to confusion or misinterpretation. A set of intuitive graphic postprocessors have also been developed providing a fast and complete visualization tool for the parameters obtained in the calculations. The capabilities and general characteristics of this deterministic software package are presented throughout the paper including several examples of its recent application.
Salgado, C A; Salgado, Carlos A.; Wiedemann, Urs Achim
2003-01-01
We calculate the probability (``quenching weight'') that a hard parton radiates an additional energy fraction due to scattering in spatially extended QCD matter. This study is based on an exact treatment of finite in-medium path length, it includes the case of a dynamically expanding medium, and it extends to the angular dependence of the medium-induced gluon radiation pattern. All calculations are done in the multiple soft scattering approximation (Baier-Dokshitzer-Mueller-Peign\\'e-Schiff--Zakharov ``BDMPS-Z''-formalism) and in the single hard scattering approximation (N=1 opacity approximation). By comparison, we establish a simple relation between transport coefficient, Debye screening mass and opacity, for which both approximations lead to comparable results. Together with this paper, a CPU-inexpensive numerical subroutine for calculating quenching weights is provided electronically. To illustrate its applications, we discuss the suppression of hadronic transverse momentum spectra in nucleus-nucleus colli...
13,14B(n, γ) via Coulomb Dissociation for Nucleosynthesis towards the r-Process
Altstadt, S. G.; Adachi, T.; Aksyutina, Y.; Alcantara, J.; Alvarez-Pol, H.; Ashwood, N.; Atar, L.; Aumann, T.; Avdeichikov, V.; Barr, M.; Beceiro, S.; Bemmerer, D.; Benlliure, J.; Bertulani, C. A.; Boretzky, K.; Borge, M. J. G.; Burgunder, G.; Caamano, M.; Caesar, C.; Casarejos, E.; Catford, W.; Cederkäll, J.; Chakraborty, S.; Chartier, M.; Chulkov, L.; Cortina-Gil, D.; Datta Pramanik, U.; Diaz Fernandez, P.; Dillmann, I.; Elekes, Z.; Enders, J.; Ershova, O.; Estrade, A.; Farinon, F.; Fraile, L. M.; Freer, M.; Freudenberger, M.; Fynbo, H. O. U.; Galaviz, D.; Geissel, H.; Gernhäuser, R.; Göbel, K.; Golubev, P.; Gonzalez Diaz, D.; Hagdahl, J.; Heftrich, T.; Heil, M.; Heine, M.; Heinz, A.; Henriques, A.; Holl, M.; Holt, J. D.; Ickert, G.; Ignatov, A.; Jakobsson, B.; Johansson, H. T.; Jonson, B.; Kalantar-Nayestanaki, N.; Kanungo, R.; Kelic-Heil, A.; Knöbel, R.; Kröll, T.; Krücken, R.; Kurcewicz, J.; Kurz, N.; Labiche, M.; Langer, C.; Le Bleis, T.; Lemmon, R.; Lepyoshkina, O.; Machado, J.; Marganiec, J.; Maroussov, V.; Menéndez, J.; Mostazo, M.; Movsesyan, A.; Najafi, M. A.; Nilsson, T.; Nociforo, C.; Panin, V.; Perea, A.; Pietri, S.; Plag, R.; Prochazka, A.; Rahaman, A.; Rastrepina, G.; Reifarth, R.; Ribeiro, G.; Ricciardi, M. V.; Rigollet, C.; Riisager, K.; Röder, M.; Rossi, D.; Sanchez del Rio, J.; Savran, D.; Scheit, H.; Schwenk, A.; Simon, H.; Simonis, J.; Sonnabend, K.; Sorlin, O.; Stoica, V.; Streicher, B.; Taylor, J.; Tengblad, O.; Terashima, S.; Thies, R.; Togano, Y.; Uberseder, E.; Van de Walle, J.; Velho, P.; Volkov, V.; Wagner, A.; Wamers, F.; Weick, H.; Weigand, M.; Wheldon, C.; Wilson, G.; Wimmer, C.; Winfield, J. S.; Woods, P.; Yakorev, D.; Zhukov, M. V.; Zilges, A.; Zoric, M.; Zuber, K.
2014-06-01
Radioactive beams of 14,15B produced by fragmentation of a primary 40Ar beam were directed onto a Pb target to investigate the neutron breakup within the Coulomb field. The experiment was performed at the LAND/R3B setup. Preliminary results for the Coulomb dissociation cross sections as well as for the astrophysically interesting inverse reactions, 13,14B(n,γ), are presented.
Interband coulomb interaction and horizontal line nodes in triplet superconductor Sr sub 2 RuO sub 4
Hasegawa, Y
2003-01-01
A possible mechanism for appearance of the horizontal line nodes in triplet superconductor, Sr sub 2 RuO sub 4 , is proposed. We consider the interlayer Coulomb interaction, as well as the on-site Coulomb repulsion, between electrons in different bands. In the second order perturbation of the interband interaction, the effective interaction becomes dependent on cos q sub z /2, resulting in horizontal line nodes. (author)
Wisniewski, H.; Gourdain, P.-A.
2017-10-01
APOLLO is an online, Linux based plasma calculator. Users can input variables that correspond to their specific plasma, such as ion and electron densities, temperatures, and external magnetic fields. The system is based on a webserver where a FastCGI protocol computes key plasma parameters including frequencies, lengths, velocities, and dimensionless numbers. FastCGI was chosen to overcome security problems caused by JAVA-based plugins. The FastCGI also speeds up calculations over PHP based systems. APOLLO is built upon the WT library, which turns any web browser into a versatile, fast graphic user interface. All values with units are expressed in SI units except temperature, which is in electron-volts. SI units were chosen over cgs units because of the gradual shift to using SI units within the plasma community. APOLLO is intended to be a fast calculator that also provides the user with the proper equations used to calculate the plasma parameters. This system is intended to be used by undergraduates taking plasma courses as well as graduate students and researchers who need a quick reference calculation.
First principles calculations of niobium substitution in strontium titanate
Energy Technology Data Exchange (ETDEWEB)
Astala, R.; Bristowe, P.D. [Department of Materials Science and Metallurgy, University of Cambridge, Cambridge (United Kingdom)
2002-02-18
We have studied the effects of Nb incorporation in strontium titanate using DFT plane-wave pseudopotential calculations. Substitution of the impurity on a Ti site in the bulk crystal causes outward relaxations of the neighbouring Ti ions but does not affect the oxygen ions. A conduction band state localized on the Ti ions becomes occupied confirming the donor behaviour of the defect. The formation energy of the impurity is studied under different oxidation conditions. We have also studied the incorporation of Nb near to a {sigma}=3(111) grain boundary. The results indicate that Nb segregation is unfavourable due to Coulomb repulsion effects. (author). Letter-to-the-editor.
Coulomb stress change on surrounding faults by the January 12, 2010, Haiti earthquake
Symithe, S. J.; Calais, E.; Freed, A. M.; Haase, J. S.
2011-12-01
The M7 January 12, 2010, Haiti earthquake occurred on the previously unmapped Léogâne Fault, a transpressional fault located very close to the Enriquillo Plantain Garden Fault (EPGF), the major fault system and primary seismic hazard in southern Haiti. How the rupture of the Léogâne fault influenced stresses on the Enriquillo Fault - especially toward Port-au-Prince - as well as on other regional faults is critical to understanding how seismic hazard in this heavily populated region has been altered as a result of the devastating 2010 earthquake. We calculated Coulomb Failure Stress (CFS) changes in the region surrounding the M7 January 12, 2010, Haiti earthquake using dislocation theory, assuming elastic properties for the region. We considered two possible slip models, the simple single-fault slip model proposed by Calais et al. (2010) and the more complex model by Hayes et al. (2010), which involves three subfaults. We resolve CFS changes on the Léogâne rupture plane itself, as well as on regional faults such as the Enriquillo, Neiba-Matheux, and Trois Baies faults. We find that the aftershock distribution is well explained by CFS changes caused by the coseismic rupture, in particular the cluster of reverse faulting events to the west of the rupture, offshore, coincident with the Trois Baies fault. This fault therefore appears to have been triggered by the January 2010 event. The aftershock distribution in the rupture area clearly outlines the Léogâne fault (see Douilly et al., this meeting) but shows no clear evidence of activity on the other subfaults suggested by Hayes et al. (2010). Both slip models imply a ~1 bar increase of CFS bar on the Enriquillo fault to the west and east of the January 2010 rupture. For the Calais et al. (2010) model, CFS changes are higher to the east if the Enriquillo Fault is modeled with a dip of 65° and a rake 20°, as suggested by some geological observations, compared to a purely strike-slip vertical fault, as often
Directory of Open Access Journals (Sweden)
Morales-Rivera J.C.
2017-01-01
Full Text Available Calculations of breakup and direct proton transfer for the 8B+58Ni system at energies around the Coulomb barrier (EB,lab=22.95 MeV were performed by the continuum-discretized coupled channels (CDCC method and the coupled-reaction-channels (CRC method, respectively. For the 7Be+58Ni interaction, we used a semimicroscopic optical model potential (OMP that combines microscopic calculations of the mean-field double folding potential and a phenomenological construction of the dynamical polarization potential (DPP. The 7Be angular distribution at Elab=25.75 MeV from the 8B breakup on 58Ni was calculated and the spectroscopic factor for 8B → 7Be+p vertex, Sexpt = 1.10 ± 0.05, was deduced. The astrophysical S17(0 factor was calculated equal to 20.7 ±1.1 eV•b, being in good agreement with the previously reported values.
Atomic structure calculations and identification of EUV and SXR spectral lines in Sr XXX
Goyal, Arun; Khatri, Indu; Aggarwal, Sunny; Singh, A. K.; Mohan, Man
2015-08-01
We report an extensive theoretical study of atomic data for Sr XXX in a wide range with L-shell electron excitations to the M-shell. We have calculated energy levels, wave-function compositions and lifetimes for lowest 113 fine structure levels and wavelengths of an extreme Ultraviolet (EUV) and soft X-ray (SXR) transitions. We have employed multi-configuration Dirac Fock method (MCDF) approach within the framework of Dirac-Coulomb Hamiltonian including quantum electrodynamics (QED) and Breit corrections. We have also presented the radiative data for electric and magnetic dipole (E1, M1) and quadrupole (E2, M2) transitions from the ground state. We have made comparisons with available energy levels compiled by NIST and achieve good agreement. But due to inadequate data in the literature, analogous relativistic distorted wave calculations have also been performed using flexible atomic code (FAC) to assess the reliability and accuracy of our results. Additionally, we have provided new atomic data for Sr XXX which is not published elsewhere in the literature and we believe that our results may be beneficial in fusion plasma research and astrophysical investigations and applications.
Energy Technology Data Exchange (ETDEWEB)
Centelles, M.; Vinas, X.; Barranco, M. (Departament d' Estructura i Constituents de la Materia, Facultat de Fisica, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona (Spain)); Ohtsuka, N.; Faessler, A.; Khoa, D.T.; Muether, H. (Institut fuer Theoretische Physik, Universitaet Tuebingen, Auf der Morgenstelle 14, D-7400 Tuebingen (Germany))
1993-03-01
A relativistic energy density functional is constructed to investigate the Dirac effects on different properties of the structure and scattering of finite nuclei. The kinetic energy density has been derived within a relativistic extended Thomas-Fermi model and includes gradient corrections to second order in [h bar]. The effective mass and the volume term of the potential energy density have been obtained from a local density approximation to Dirac-Brueckner calculations of nuclear matter carried out with a realistic nucleon-nucleon interaction. This volume term is supplemented by the Coulomb energy and by conventional phenomenological surface and symmetry terms, and the few free parameters of the functional are suitably adjusted. Attention is then focused on the calculation of fission barriers of rotating nuclei and of the complex optical potential for heavy ion collisions at intermediate energies. It turns out that the effects of the density-dependent Dirac spinor which have been incorporated in this approach allow for a reasonable description of the investigated properties.
Hergenhahn, Uwe
2012-12-01
The paper gives an introduction into Interatomic and Intermolecular Coulombic Decay (ICD). ICD is an autoionization process, which contrary to Auger decay involves neighbouring sites of the initial vacancy as an integral part of the decay transition. As a result of ICD, slow electrons are produced which generally are known to be active in radiation damage. The author summarizes the properties of ICD and reviews a number of important experiments performed in recent years. Intermolecular Coulombic Decay can generally take place in weakly bonded aggregates in the presence of ionizing particles or ionizing radiation. Examples collected here mostly use soft X-rays produced by synchrotron radiation to ionize, and use rare-gas clusters, water clusters or solutes in a liquid jet to observe ICD after irradiation. Intermolecular Coulombic Decay is initiated by single ionization into an excited state. The subsequent relaxation proceeds via an ultra-fast energy transfer to a neighbouring site, where a second ionization occurs. Secondary electrons from ICD have clearly been identified in numerous systems. ICD can take place after primary ionization, as the second step of a decay cascade which also involves Auger decay, or after resonant excitation with an energy which exceeds the ionization potential of the system. ICD is expected to play a role whenever particles or radiation with photon energies above the ionization energies for inner valence electrons are present in weakly bonded matter, e.g., biological tissue. The process produces at the same time a slow electron and two charged atomic or molecular fragments, which will lead to structural changes around the ionized site.
Effect of increasing disorder on domains of the 2d Coulomb glass
Bhandari, Preeti; Malik, Vikas
2017-12-01
We have studied a two dimensional lattice model of Coulomb glass for a wide range of disorders at T∼ 0 . The system was first annealed using Monte Carlo simulation. Further minimization of the total energy of the system was done using an algorithm developed by Baranovskii et al, followed by cluster flipping to obtain the pseudo-ground states. We have shown that the energy required to create a domain of linear size L in d dimensions is proportional to Ld-1 . Using Imry–Ma arguments given for random field Ising model, one gets critical dimension d_c≥slant 2 for Coulomb glass. The investigation of domains in the transition region shows a discontinuity in staggered magnetization which is an indication of a first-order type transition from charge-ordered phase to disordered phase. The structure and nature of random field fluctuations of the second largest domain in Coulomb glass are inconsistent with the assumptions of Imry and Ma, as was also reported for random field Ising model. The study of domains showed that in the transition region there were mostly two large domains, and that as disorder was increased the two large domains remained, but a large number of small domains also opened up. We have also studied the properties of the second largest domain as a function of disorder. We furthermore analysed the effect of disorder on the density of states, and showed a transition from hard gap at low disorders to a soft gap at higher disorders. At W=2 , we have analysed the soft gap in detail, and found that the density of states deviates slightly (δ≈ 1.293 +/- 0.027 ) from the linear behaviour in two dimensions. Analysis of local minima show that the pseudo-ground states have similar structure.
Lee, Wonjoo; Lee, Seung Yong; Zhang, Xin; Rabin, Oded; Briber, R. M.
2013-02-01
We present a novel and simple method for forming hexagonal gold nanoparticle arrays that uses Coulombic interactions between negatively charged gold nanoparticles on positively charged vertically oriented poly(4-vinylpyridine) cylinders formed in a spin cast polystyrene-b-poly(4-vinylpyridine) block copolymer film. Exposure of the block copolymer film to dibromobutane vapor quaternizes and crosslinks the poly(4-vinylpyridine) domains which allows for the templated deposition of gold nanoparticles into a self-assembled hexagonal array through electrostatic interactions. These systems can form the basis for sensors or next generation nanoparticle based electronics.
Aspects of Coulomb dissociation and interference in peripheral nucleus-nucleus collisions
Energy Technology Data Exchange (ETDEWEB)
Nystrand, Joakim; Baltz, Anthony; Klein, Spencer R.
2001-10-21
Coherent vector meson production in peripheral nucleus-nucleus collisions is discussed. These interactions may occur for impact parameters much larger than the sum of the nuclear radii. Since the vector meson production is always localized to one of the nuclei, the system acts as a two-source interferometer in the transverse plane. By tagging the outgoing nuclei for Coulomb dissociation it is possible to obtain a measure of the impact parameter and thus the source separation in the interferometer. This is of particular interest since the life-time of the vector mesons are generally much shorter than the impact parameters of the collisions.
Gómez Pueyo, Adrián; Budagosky M., Jorge A.; Castro, Alberto
2016-12-01
We present an implementation of optimal control theory for the first-principles nonadiabatic Ehrenfest molecular dynamics model, which describes a condensed matter system by considering classical point-particle nuclei, and quantum electrons, handled in our case with time-dependent density-functional theory. The scheme is demonstrated by optimizing the Coulomb explosion of small sodium clusters: the algorithm is set to find the optimal femtosecond laser pulses that disintegrate the clusters, for a given total duration, fluence, and cutoff frequency. We describe the numerical details and difficulties of the method.
Dynamics of braking vehicles: from Coulomb friction to anti-lock braking systems
Energy Technology Data Exchange (ETDEWEB)
Tavares, J M [Instituto Superior de Engenharia de Lisboa, Avenida Conselheiro EmIdio Navarro 1, 1959-007 Lisboa (Portugal)], E-mail: jtavares@dem.isel.ipl.pt
2009-07-15
The dynamics of braking of wheeled vehicles is studied using the Coulomb approximation for the friction between road and wheels. The dependence of the stopping distance on the mass of the vehicle, on the number of its wheels and on the intensity of the braking torque is established. It is shown that there are two regimes of braking, with and without sliding. The advantage of using an anti-lock braking system (ABS) is put in evidence, and a quantitative estimate of its efficiency is proposed and discussed.
Coulomb blockade in a Si channel gated by an Al single-electron transistor
Sun, L.; Brown, K. R.; Kane, B. E.
2007-01-01
We incorporate an Al-AlO_x-Al single-electron transistor as the gate of a narrow (~100 nm) metal-oxide-semiconductor field-effect transistor (MOSFET). Near the MOSFET channel conductance threshold, we observe oscillations in the conductance associated with Coulomb blockade in the channel, revealing the formation of a Si single-electron transistor. Abrupt steps present in sweeps of the Al transistor conductance versus gate voltage are correlated with single-electron charging events in the Si t...
Green's function for motion in Coulomb-modified separable nonlocal potentials
Energy Technology Data Exchange (ETDEWEB)
Talukdar, B.; Laha, U.; Sasakawa, T.
1986-08-01
A closed form expression is derived for the outgoing wave radial Green's function G-script/sup (+)//sub l-italic/ (r-italic,r-italic') for motion in the Coulomb plus rank one separable nonlocal potential with form factor v-italic/sub l-italic/(r-italic) = 2/sup -//sup l-italic/ x (l-italicexclamation)/sup -1/ r-italic/sup l-italic/e-italic/sup -//sup ..beta..//sup >//sup l-italic/r-italic$. Some possible applications of the result are discussed.