1,264 research outputs found
Calculation of Hydrogenic Bethe Logarithms for Rydberg States
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 141Pr(,)Pr elastic scattering and -induced reaction cross sections at low energies
Elastic scattering data for Pr(,)Pr have been
analyzed to derive a new energy-dependent local potential for the
Pr- system. This potential is used successfully to predict the
cross section of the Pr(,n)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 Pr- 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 -nucleus potential.Comment: 12 pages, 8 figures, Phys. Rev. C, accepte
Self-energy values for P states in hydrogen and low-Z hydrogenlike ions
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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