1,869 research outputs found

    Description of two-electron atoms with correct cusp conditions

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    New sets of functions with arbitrary large finite cardinality are constructed for two-electron atoms. Functions from these sets exactly satisfy the Kato's cusp conditions. The new functions are special linear combinations of Hylleraas- and/or Kinoshita-type terms. Standard variational calculation, leading to matrix eigenvalue problem, can be carried out to calculate the energies of the system. There is no need for optimization with constraints to satisfy the cusp conditions. In the numerical examples the ground state energy of the He atom is considered

    Precise Coulomb wave functions for a wide range of complex l, eta and z

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    A new algorithm to calculate Coulomb wave functions with all of its arguments complex is proposed. For that purpose, standard methods such as continued fractions and power/asymptotic series are combined with direct integrations of the Schrodinger equation in order to provide very stable calculations, even for large values of |eta| or |Im(l)|. Moreover, a simple analytic continuation for Re(z) < 0 is introduced, so that this zone of the complex z-plane does not pose any problem. This code is particularly well suited for low-energy calculations and the calculation of resonances with extremely small widths. Numerical instabilities appear, however, when both |eta| and |Im(l)| are large and |Re(l)| comparable or smaller than |Im(l)|

    Neutron Removal from the Deformed Halo 31Ne Nucleus

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    Experimental data on Coulomb breakup and neutron removal indicate that 31Ne is one of the heaviest halo nuclei discovered so far. The possible ground state of 31Ne is either 3/2- coming from p-wave halo or 1/2+ from s-wave halo. In this work, we develop a treatable model to include deformed wave functions and a dynamical knockout formalism which includes the dependence on the nuclear orientation to study the neutron removal from 31Ne projectiles at energies around E=200 MeV/nucleon. A detailed account of the effects of deformation on cross sections and longitudinal momentum distributions is made. Our numerical analysis indicates a preference for the 31Ne ground state with spin parity 3/2-.Comment: 22 pages, 13 figures, accepted for publication in the Physical Review

    Shadow poles in a coupled-channel problem calculated with Berggren basis

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    In coupled-channel models the poles of the scattering S-matrix are located on different Riemann sheets. Physical observables are affected mainly by poles closest to the physical region but sometimes shadow poles have considerable effect, too. The purpose of this paper is to show that in coupled-channel problem all poles of the S-matrix can be calculated with properly constructed complex-energy basis. The Berggren basis is used for expanding the coupled-channel solutions. The location of the poles of the S-matrix were calculated and compared with an exactly solvable coupled-channel problem: the one with the Cox potential. We show that with appropriately chosen Berggren basis poles of the S-matrix including the shadow ones can be determined.Comment: 11 pages, 4 figures, 59 reference

    Az élelmiszergazdaság külkereskedelme 2013. január-október

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    2013. január-október időszakában a mezőgazdasági és élelmiszeripari termékek kivitelének értéke 6694 millió eurót, behozatalának értéke 3764 millió eurót ért el. Az export értéke 55 millió euróval (-1 százalék) kevesebb, az import értéke 119 millió euróval (+3 százalék) magasabb volt, mint 2012. január-októberi időszakában. Az agár-külkereskedelem 2931 millió eurós aktívuma 173 millióval (-6 százalék) kevesebb, mint a bázisidőszakban
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