1,257 research outputs found

    Calculation of Hydrogenic Bethe Logarithms for Rydberg States

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    We describe the calculation of hydrogenic (one-loop) Bethe logarithms for all states with principal quantum numbers n <= 200. While, in principle, the calculation of the Bethe logarithm is a rather easy computational problem involving only the nonrelativistic (Schroedinger) theory of the hydrogen atom, certain calculational difficulties affect highly excited states, and in particular states for which the principal quantum number is much larger than the orbital angular momentum quantum number. Two evaluation methods are contrasted. One of these is based on the calculation of the principal value of a specific integral over a virtual photon energy. The other method relies directly on the spectral representation of the Schroedinger-Coulomb propagator. Selected numerical results are presented. The full set of values is available at quant-ph/0504002.Comment: 10 pages, RevTe

    Total reaction cross sections from 141^{141}141Pr(α\alpha,α\alpha)141^{141}Pr elastic scattering and α\alpha-induced reaction cross sections at low energies

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    Elastic scattering data for 141^{141}Pr(α\alpha,α\alpha)141^{141}Pr have been analyzed to derive a new energy-dependent local potential for the 141^{141}Pr-α\alpha system. This potential is used successfully to predict the cross section of the 141^{141}Pr(α\alpha,n)144^{144}Pm reaction at low energies where new experimental data have become available very recently. Contrary to various global potentials, this new potential is able to reproduce simultaneously elastic scattering data around and above the Coulomb barrier and reaction data below the Coulomb barrier for the 141^{141}Pr-α\alpha system. Reasons for the partial failure of the global potentials are explained by intrinsic properties of the scattering matrix and their variation with energy. The new local potential may become the basis for the construction of a new global α\alpha-nucleus potential.Comment: 12 pages, 8 figures, Phys. Rev. C, accepte

    Self-energy values for P states in hydrogen and low-Z hydrogenlike ions

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    We describe a nonperturbative (in Zalpha) numerical evaluation of the one-photon electron self energy for 3P_{1/2}, 3P_{3/2}, 4P_{1/2} and 4P_{3/2} states in hydrogenlike atomic systems with charge numbers Z=1 to 5. The numerical results are found to be in agreement with known terms in the expansion of the self energy in powers of Zalpha and lead to improved theoretical predictions for the self-energy shift of these states.Comment: 3 pages, RevTe
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